About me: My name is Solène Rapenne, pronouns she/her. I like learning and sharing knowledge. Hobbies: '(BSD OpenBSD Qubes OS Lisp cmdline gaming security QubesOS internet-stuff). I love percent and lambda characters. OpenBSD developer solene@. No AI is involved in this blog.

Contact me: solene at dataswamp dot org or @solene@bsd.network (mastodon).

You can sponsor my work financially if you want to help me writing this blog and contributing to Free Software as my daily job.

Cloud gaming review using Playstation Plus

Written by Solène, on 13 March 2024.
Tags: #gaming #network

Comments on Fediverse/Mastodon

1. Introduction §

While testing the cloud gaming service GeForce Now, I've learned that PlayStation also had an offer.

Basically, if you use a PlayStation 4 or 5, you can subscribe to the first two tiers to benefit some services and games library, but the last tier (premium) adds more content AND allows you to play video games on a computer with their client, no PlayStation required. I already had the second tier subscription, so I paid the small extra to switch to premium in order to experiment with the service.

PlayStation Plus official website

2. Game library §

Compared to GeForce Now, while you are subscribed you have a huge game library at hand. This makes the service a lot cheaper if you are happy with the content. The service costs 160$€ / year if you take for 12 months, this is roughly the price of 2 AAA games nowadays...

3. Streaming service §

The service is only available using the PlayStation Plus Windows program. It's possible to install it on Linux, but it will use more CPU because hardware decoding doesn't seem to work on Wine (even wine-staging with vaapi compatibility checked).

There are no clients for Android, and you can't use it in a web browser. The Xbox Game Pass streaming and GeForce now services have all of that.

Sadness will start here. The service is super promising, but the application is currently a joke.

If you don't plug a PS4 controller (named a dualshock 4), you can't use the "touchpad" button, which is mandatory to start a game in Tales of Arise, or very important in many games. If you have a different controller, on Windows you can use the program "DualShock 4 emulator" to emulate it, on Linux it's impossible to use, even with a genuine controller.

A PS5 controller (dualsense) is NOT compatible with the program, the touchpad won't work.

DualShock4 emulator GitHub project page

Obviously, you can't play without a controller, except if you use a program to map your keyboard/mouse to a fake controller.

4. Gaming quality §

There are absolutely no settings in the application, you can run a game just by clicking on it, did I mention there are no way to search for a game?

I guess games are started in 720p, but I'm not sure, putting the application full screen didn't degrade the quality, so maybe it's 1080p but doesn't go full screen when you run it...

Frame rate... this sucks. Games seem to run on a PS4 fat, not a PS4 pro that would allow 60 fps. On most games you are stuck with 30 fps and an insane input lag. I've not been able to cope with AAA games like God of War or Watch Dogs Legion as it was horrible.

Independent games like Alex Kidd remaster, Monster Boy or Rain World did feel very smooth though (60fps!), so it's really an issue with the hardware used to run the games.

Don't expect any PS5 games in streaming from Windows, there are none.

The service allows PlayStation users to play all games from the library (including PS5 games) in streaming up to 2160p@120fps, but not the application users. This feature is only useful if you want to try a game before installing it, or if your PlayStation storage is full.

5. Cloud saving §

This is fun here too. There are game saves in the PlayStation Plus program cloud, but if you also play on a PlayStation, their saves are sent to a different storage than the PlayStation cloud saves.

There is a horrible menu to copy saves from one pool to the other.

This is not an issue if you only use the stream application or the PlayStation, but it gets very hard to figure where is your save if you play on both.

6. Conclusion §

I have been highly disappointed by the streaming service (outside PlayStation use). The Windows programs required to sign in twice before working (I tried on 5 devices!), most interesting games run poorly due to a PS4 hardware, there is no way to enable the performance mode that was added to many games to support the PS4 Pro. This is pretty curious as the streaming from a PlayStation device is a stellar experience, it's super smooth, high quality, no input lag, no waiting, crystal clear picture.

No Android application? Curious... No support for a genuine PS5 controller, WTF?

The service is still young, I really hope they will work at improving the streaming ecosystem.

At least, it works reliably and pretty well for simpler games.

It could be a fantastic service if the following requirements were met:

  • proper hardware to run games at 60fps
  • greater controller support
  • allow playing in a web browser, or at least allow people to run it on smartphones with a native application
  • an open source client while there
  • merged cloud saves

Cloud gaming review using Geforce Now

Written by Solène, on 07 March 2024.
Tags: #gaming #network #unix

Comments on Fediverse/Mastodon

1. Introduction §

I'm finally done with ADSL now as I got access to optical fiber last week! It was time for me to try cloud gaming again and see how it improved since my last use in 2016.

If you are not familiar with cloud gaming, please do not run away, here is a brief description. Cloud gaming refers to a service allowing one to play locally a game running on a remote machine (either locally or over the Internet).

There are a few commercial services available, mainly: GeForce Now, PlayStation Plus Premium (other tiers don't have streaming), Xbox game pass Ultimate and Amazon Luna. Two major services died in the long run: Google Stadia and Shadow (which is back now with a different formula).

A note on Shadow, they are now offering access to an entire computer running Windows, and you do what you want with it, which is a bit different from other "gaming" services listed above. It's expensive, but not more than renting an AWS system with equivalent specs (I know some people doing that for gaming).

This article is about the service Nvidia GeForce Now (not sponsored, just to be clear).

I tried the free tier, premium tier and ultimate tier (thanks to people supporting me on Patreon, I could afford the price for this review).

Geforce Now official page

Geforce Now page where you play (not easy to figure after a login)

2. The service §

This is the first service I tried in 2016 when I received an Nvidia Shield HTPC, the experience was quite solid back in the days. But is it good in 2024?

The answer is clear, yes, it's good, but it has limitations you need to be aware of. The free tier allows playing for a maximum of 1 hour in a single session, and with a waiting queue that can be fast (< 1 minute) or long (> 15 minutes), but the average waiting time I had was like 9 minutes. The waiting queue also displays ads now.

The premium tier at 11€$/month removes the queue system by giving you priority over free users, always assigns an RTX card and allows playing up to 6 hours in a single session (you just need to start a new session if you want to continue).

Finally, the ultimate tier costs 22€$/month and allows you to play in 4K@120fps on a RTX 4080, up to 8h.

The tiers are quite good in my opinion, you can try and use the service for free to check if it works for you, then the premium tier is affordable to be used regularly. The ultimate tier will only be useful to advanced gamers who need 4K, or higher frame rates.

Nvidia just released a new offer early March 2024, a premium daily pass for $3.99 or ultimate daily pass for 8€. This is useful if you want to evaluate a tier before deciding if you pay for 6 months. You will understand later why this daily pass can be useful compared to buying a full month.

3. Operating system support §

I tried the service using a Steam Deck, a Linux computer over Wi-Fi and Ethernet, a Windows computer over Ethernet and in a VM on Qubes OS. The latency and quality were very different.

If you play in a web browser (Chrome based, Edge, Safari), make sure it supports hardware acceleration video decoding, this is the default for Windows but a huge struggle on Linux, Chrome/Chromium support is recent and can be enabled using chromium --enable-features=VaapiVideoDecodeLinuxGL --use-gl=angle. There is a Linux Electron App, but it does nothing more than bundling the web page in chromium, without acceleration.

On a web browser, the codec used is limited to h264 which does not work great with dark areas, it is less effective than advanced codecs like av1 or hevc (commonly known as h265). If you web browser can't handle the stream, it will lose packets and then Geforce service will instantly reduce the quality until you do not lose packets, which will make things very ugly until it recover, until it drops again. Using hardware acceleration solves the problem almost entirely!

Web browser clients are also limited to 60 fps (so ultimate tier is useless), and Windows web browsers can support 1440p but no more.

On Windows and Android you can install a native Geforce Now application, and it has a LOT more features than in-browser. You can enable Nvidia reflex to remove any input lag, HDR for compatible screens, 4K resolution, 120 fps frame rate etc... There is also a feature to add color filters for whatever reason... The native program used AV1 (I only tried with the ultimate tier), games were smooth with stellar quality and not using more bandwidth than in h264 at 60 fps.

I took a screenshot while playing Baldur's Gate 3 on different systems, you can compare the quality:

Playing on Steam native program, game set to maximum quality
Playing on Steam native program, game set to maximum quality
Playing on Geforce Now on Windows native app, game set to maximum quality
Playing on Geforce Now on Windows native app, game set to maximum quality
Playing on Geforce Now on Linux with hardware acceleration, game set to maximum quality
Playing on Geforce Now on Linux with hardware acceleration, game set to maximum quality

In my opinion, the best looking one is surprisingly the Geforce Now on Windows, then the native run on Steam and finally on Linux where it's still acceptable. You can see a huge difference in terms of quality in the icons in the bottom bar.

4. Tier system §

When I upgraded from free to premium tier, I paid for 1 month and was instantly able to use the service as a premium user.

Premium gives you priority in the queues, I saw the queue display a few times for a few seconds, so there is virtually no queue, and you can play for 6 hours in a row.

When I upgraded from premium to ultimate tier, I was expecting to pay the price difference between my current subscription and the new one, but it was totally different. I had to pay for a whole month of ultimate tier, and my current remaining tier was converted as an ultimate tier, but as ultimate costs a bit more than twice premium, a pro rata was applied to the premium time, resulting in something like 12 extra days of ultimate for the premium month.

Ultimate tier allows reaching a 4K resolution and 120 fps refresh rate, allow saving video settings in games, so you don't have to tweak them every time you play, and provide an Nvidia 4080 for every session, so you can always set the graphics settings to maximum. You can also play up to 8 hours in a row. Additionaly, you can record gaming sessions or the past n minutes, there is a dedicated panel using Ctrl+G. It's possible to achieve 240 fps for compatible monitors, but only for 1080p resolution.

Due to the tier upgrade method, the ultimate pass can be interesting, if you had 6 months of premium, you certainly don't want to convert it into 2 months of ultimate + paying 1 month of ultimate just to try.

5. Gaming quality §

As a gamer, I'm highly sensitive to latency, and local streaming has always felt poor with regard to latency, and I've been very surprised to see I can play an FPS game with a mouse on cloud gaming. I had a ping of 8-75 ms with the streaming servers, which was really OK. Games featuring "Nvidia reflex" have no sensitive input lag, this is almost magic.

When using a proper client (native Windows client or a web browser with hardware acceleration), the quality was good, input lag barely noticeable (none in the app), it made me very happy :-)

Using the free tier, I always had a rig good enough to put the graphics quality on High or Ultra, which surprised me for a free service. On premium and later, I had an Nvidia 2080 minimum which is still relevant nowadays.

The service can handle multiple controllers! You can use any kind of controller, and even mix Xbox / PlayStation / Nintendo controllers, no specific hardware required here. This is pretty cool as I can visit my siblings, bring controllers and play together on their computer <3.

Another interesting benefit is that you can switch your gaming session from a device to another by connecting with the other device while already playing, Geforce Now will switch to the new connecting device without interruption.

6. Games library §

This is where GeForce now is pretty cool, you don't need to buy games to them. You can import your own libraries like Steam, Ubisoft, Epic store, GOG (only CD Projekt Red games) or Xbox Game Pass games. Not all games from your libraries will be playable though! And for some reasons, some games are only available when run from Windows (native app or web browser), like Genshin Impact which won't appear in the games list if connected from non-Windows client?!

If you already own games (don't forget to claim weekly free Epic store games), you can play most of them on GeForce Now, and thanks to cloud saves, you can sync progression between sessions or with a local computer.

There are a bunch of free-to-play games that are good (like Warframe, Genshin Impact, some MMOs), so you could enjoy playing video games without having to buy one (until you get bored?).

7. Cost efficiency §

If you don't currently own a modern gaming computer, and you subscribe to the premium tier (9.17 $€/month when signing for 6 months), this costs you 110 $€ / year.

Given an equivalent GPU costs at least 400€$ and could cope with games in High quality for 3 years (I'm optimistic), the GPU alone costs more than subscribing to the service. Of course, a local GPU can be used for data processing nowadays, or could be sold second hand, or be used for many years on old games.

If you add the whole computer around the GPU, renewed every 5 or 6 years (we are targeting to play modern games in high quality here!), you can add 1200 $€ / 5 years (or 240 $€ / year).

When using the ultimate tier, you instantly get access to the best GPU available (currently a Geforce 4080, retail value of 1300€$). Cost wise, this is impossible to beat with owned hardware.

I did some math to figure how much money you can save from electricity saving: the average gaming rig draws approximately 350 Watts when playing, a Geforce now thin client and a monitor would use 100 Watts in the worst case scenario (a laptop alone would be more around 35 Watts). So, you save 0.25 kWh per hour of gaming, if one plays 100 hours per month (that's 20 days playing 5h, or 3.33 hours / day) they would save 25 kWh. The official rate in France is 0.25 € / kWh, that would result in a 6.25€ saving in electricity. The monthly subscription is immediately less expensive when taking this into account. Obviously, if you are playing less, the savings are less important.

8. Bandwidth usage and ecology §

Most of the time, the streaming was using between 3 and 4 MB/s for a 1080p@60fps (full-hd resolution, 1920x1080, at 60 frames per second) in automatic quality mode. Playing at 30 fps or on smaller resolutions will use drastically less bandwidth. I've been able to play in 1080p@30 on my old ADSL line! (quality was degraded, but good enough). Playing at 120 fps slightly increased the bandwidth usage by 1 MB/s.

I remember a long tech article about ecology and cloud gaming which concluded cloud gaming is more "eco-friendly" than running locally if you play it less than a dozen hours. However, it always assumed you had a capable gaming computer locally that was already there, whether you use the cloud gaming or not, which is a huge bias in my opinion. It also didn't account that one may install a video games multiple times and that a single game now weights 100 GB (which is equivalent to 20h of cloud gaming bandwidth wise!). The biggest cons was the bandwidth requirements and the whole worldwide maintenance to keep high speed lines for everyone. I do think Cloud gaming is way more effective as it allows pooling gaming devices instead of having everyone with their own hardware.

As a comparison, 4K streaming at Netflix uses 25 Mbps of network (~ 3.1 MB/s).

9. Playing on Android §

Geforce Now allows you to play any compatible game on Android, is it worth? I tried it with a Bluetooth controller on my BQ Aquaris X running LineageOS (it's a 7 years old phone, average specs with a 720p screen).

I was able to play in Wi-Fi using the 5 GHz network, it felt perfect except that I had to put the smartphone screen in a comfortable way. This was drawing the battery at a rate of 0.7% / minute, but this is an old phone, I expect newer hardware to do better.

On 4G, the battery usage was less than Wi-Fi with 0.5% / minute. The service at 720p@60fps used an average of 1.2 MB/s of data for a gaming session of Monster Hunter world. At this rate, you can expect a data usage of 4.3 GB / hour of gameplay, which could be a lot or cheap depending on your usage and mobile subscription.

Globally, playing on Android was very good, but only if you have a controller. There are interesting folding controllers that sandwich the smartphone between two parts, turning it into something looking like a Nintendo Switch, this can be a very interesting device for players.

10. Tips §

You can use "Ctrl+G" to change settings while in game or also display information about the streaming.

In GeForce Now settings (not in-game), you can choose the servers location if you want to try a different datacenter. I set to choose the nearest otherwise I could land on a remote one with a bad ping.

GeForce Now even works on OpenBSD or Qubes OS qubes (more on that later on Qubes OS forum!).

Qubes OS forum discussion

11. Conclusion §

GeForce Now is a pretty neat service, the free tier is good enough for occasional gamers who would play once in a while for a short session, but also provide a cheaper alternative than having to keep a gaming rig up-to-date. I really like that they allow me to use my own library instead of having to buy games on their own store.

I'm preparing another blog post about local and self hosted cloud gaming, and I have to admit I haven't been able to do better than Geforce Now even on local network... Engineers at Geforce Now certainly know their stuff!

The experience was solid even on a 10 years old laptop, and enjoyable. A "cool" feature when playing is the surrounding silence, as no CPU/GPU are crunching for rendering! My GPU is still capable to handle modern games at an average quality at 60 FPS, I may consider using the premium tier in the future instead of replacing my GPU.

Script NAT on Qubes OS

Written by Solène, on 06 March 2024.
Tags: #qubesos #unix #network

Comments on Fediverse/Mastodon

1. Introduction §

As a daily Qubes OS user, I often feel the need to expose a port of a given qube to my local network. However, the process is quite painful because it requires doing the NAT rules on each layer (usually net-vm => sys-firewall => qube), it's a lost of wasted time.

I wrote a simple script that should be used from dom0 that does all the job: opening the ports on the qube, and for each NetVM, open and redirect the ports.

Qubes OS Nat git repository

2. Usage §

It's quite simple to use, the hardest part will be to remember how to copy it to dom0 (download it in a qube and use qvm-run --pass-io from dom0 to retrieve it).

Make the script executable with chmod +x nat.sh, now if you want to redirect the port 443 of a qube, you can run ./nat.sh qube 443 tcp. That's all.

Be careful, the changes ARE NOT persistent. This is on purpose, if you want to always expose ports of a qube to your network, you should script its netvm accordingly.

3. Limitations §

The script is not altering the firewall rules handled by qvm-firewall, it only opens the ports and redirect them (this happens at a different level). This can be cumbersome for some users, but I decided to not touch rules that are hard-coded by users in order to not break any expectations.

Running the script should not break anything. It works for me, but it was only slightly tested though.

4. Some useful ports §

4.1. Avahi daemon port §

The avahi daemon uses the UDP port 5353. You need this port to discover devices on a network. This can be particularly useful to find network printers or scanners and use them in a dedicated qube.

5. Evolutions §

It could be possible to use this script in qubes-rpc, this would allow any qube to ask for a port forwarding. I was going to write it this way at first, but then I thought it may be a bad idea to allow a qube to run a dom0 script as root that requires reading some untrusted inputs, but your mileage may vary.

Some OpenBSD features that aren't widely known

Written by Solène, on 20 February 2024.
Tags: #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

In this blog post, you will learn about some OpenBSD features that can be useful, but not widespread.

They often have a niche usage, but it's important to know they exist to prevent you from reinventing the wheel :)

OpenBSD official project website

2. Features §

The following list of features are not all OpenBSD specific as some can be found on other BSD systems. Most of the knowledge will not be useful to Linux users.

2.1. Secure level §

The secure level is a sysctl named kern.securelevel, it has 4 different values from level -1 to level 2, and it's only possible to increase the level. By default, the system enters the secure level 1 when in multi-user (the default when booting a regular installation).

It's then possible to escalate to the last secure level (2), which will enable the following extra security:

  • all raw disks are read-only, so it's not possible to try to make a change to the storage devices
  • the time is almost lock, it's only possible to modify the clock slowly by small steps (maybe 1 second max every so often)
  • the PF firewall rules can't be modified, flushed or altered

This feature is mostly useful for dedicated firewall with rules that rarely change. Preventing the time to change is really useful for remote logging as it allows being sure of "when" things happened, and you can be assured the past logs weren't modified.

The default security level 1 already enable some extra security like "immutable" and "append-only" file flags can't be removed, these overlooked flags (that can be applied with chflags) can lock down files to prevent anyone from modifying them. The append-only flag is really useful for logs because you can't modify the content, but this doesn't prevent adding new content, history can't be modified this way.

OpenBSD manual pages: securelevel

OpenBSD manual pages: chflags

This feature exists in other BSD systems.

2.2. Memory allocator extra checks §

OpenBSD's memory allocator can be tweaked, system-wide or per command, to add extra checks. This could be either used for security reasons or to look for memory allocation related bugs in a program (this is VERY common...).

There are two methods to apply the changes:

  • system-wide by using the sysctl vm.malloc_conf, either immediately with the sysctl command, or at boot in /etc/sysctl.conf (make sure you quote its value there, some characters such as > will create troubles otherwise, been there...)
  • on the command line by prepending env MALLOC_OPTIONS="flags" program_to_run

The man page gives a list of flags to use as option, the easiest to use is S (for security checks). It is stated in the man page that a program misbehaving with any flag other than X is buggy, so it's not YOUR fault if you use malloc options and the program is crashing.

OpenBSD manual pages: malloc (search for MALLOC OPTIONS)

2.3. File flags §

You are certainly used to files attributes like permissions or ownership, but on many file systems (including OpenBSD ffs), there are flags as well!

The file flags can be altered with the command chflags, there are a couple of flags available:

  • nodump: prevent the files from being saved by the command dump (except if you use a flag in dump to bypass this)
  • sappnd: the file can only be used in writing append mode, only root can set / remove this flag
  • schg: the file can not be change, it becomes immutable, only root can alter this flag
  • uappnd: same as sappnd mode but the user can alter the flag
  • uchg: same as schg mode but the user can alter the flag

As explained in the secure level section above, in the secure level 1 (default !), the flags sappnd and schg can't be removed, you would need to boot in single user mode to remove these flags.

Tip: remove the flags on a file with chflags 0 file [...]

You can check the flags on files using ls -ol, this would look like this:

terra$ chflags uchg get_extra_users.sh
terra$ ls -lo get_extra_users.sh        
-rwxr-xr-x  1 solene  solene  uchg 749 Apr  3  2023 get_extra_users.sh

terra$ chflags 0 get_extra_users.sh     
terra$ ls -lo get_extra_users.sh     
-rwxr-xr-x  1 solene  solene  - 749 Apr  3  2023 get_extra_users.sh

OpenBSD manual pages: chflags

2.4. Crontab extra parameters §

OpenBSD crontab format received a few neat additions over the last years.

  • random number for time field: you can use ~ in a field instead of a number or * to generate a random value that will remain stable until the crontab is reloaded. Things like ~/5 work. You can force the random value within a range with 20~40 to get values between 20 and 40.
  • only send an email if the return code isn't 0 for the cron job: add -n between the time and the command, like in 0 * * * * -n /bin/something.
  • only run one instance of a job at a time: add -s between the time and the command, like in * * * * * -s /bin/something. This is incredibly useful for cron job that shouldn't be running twice in parallel, if the job duration is longer than usual, you are ensured it will never start a new instance until the previous one is done.
  • no logging: add -q between the time and the command, like in * * * * -q /bin/something, the effect will be that this cron job will not be logged in /var/cron/log.

It's possible to use a combination of flags like -ns. The random time is useful when you have multiple systems, and you don't want them to all run a command at the same time, like in a case they would trigger a huge I/O on a remote server. This was created to prevent the usual 0 * * * * sleep $(( $RANDOM % 3600 )) && something that would run a sleep command for a random time up to an hour before running a command.

OpenBSD manual pages: crontab

2.5. Auto installing media §

One cool feature on OpenBSD is the ability to easily create an installation media with pre-configured answers. This is done by injecting a specific file in the bsd.rd install kernel.

There is a simple tool named upobsd that was created by semarie@ to easily modify such bsd.rd file to include the autoinstall file, I forked the project to continue its maintenance.

In addition to automatically installing OpenBSD with users, ssh configuration, sets to install etc... it's also possible to add a site.tgz archive along with the usual sets archives that includes files you want to add to the system, this can include a script to run at first boot to trigger some automation!

These features are a must-have if you run OpenBSD in production, and you have many of them to manage, enrolling a new device to the fleet should be automated as possible.

GitHub project page: upobsd

OpenBSD manual pages: autoinstall

2.6. apmd daemon hooks §

Apmd is certainly running on most OpenBSD laptop and desktop around, but it has features that aren't related to its command line flags, so you may have missed them.

There are different file names that can contain a script to be run upon some event such as suspend, resume, hibernate etc...

A classic usage is to run xlock in one's X session on suspend, so the system will require a password on resume.

Older blog post: xlock from apmd suspend script

The man page explains all, but basically this works like this for running a backup program when you connect your laptop to the power plug:

# mkdir -p /etc/apm
# vi /etc/apm/powerup

You need to write a regular script:

#!/bin/sh

/usr/local/bin/my_backup_script

Then, make it executable

# chmod +x /etc/apm/powerup

The daemon apmd will automatically run this script when you connect a system back to AC power.

The method is the same for:

  • hibernate
  • resume
  • suspend
  • standby
  • hibernate
  • powerup
  • powerdown

This makes it very easy to schedule tasks on such events.

OpenBSD manual page: apmd (section FILES)

2.7. Using hotplugd for hooks on devices events §

A bit similar to what apmd by running a script upon events, hotplugd is a service that allow running a script when a device is added / removed.

A typical use is to automatically mount an USB memory stick when plugged in the system, or start cups daemon when powering on your USB printer.

The script receives two parameters that represents the device class and device name, so you can use them in your script to know what was connected. The example provided in the man page is a good starting point.

The scripts aren't really straightforward to write, you need to make a precise list of hardware you expect and what to run for each, and don't forget to skip unknown hardware. Don't forget to make the scripts executable, otherwise it won't work.

OpenBSD manual page: hotplugd

2.8. Altroot §

Finally, there is a feature that looks pretty cool. In the daily script, if an OpenBSD partition /altroot/ exists in /etc/fstab and the daily script environment has a variable ROOTBACKUP=1, the root partition will be duplicated to it. This permit keeping an extra root partition in sync with the main root partition. Obviously, it's more useful if the altroot partition is on another drive. The duplication is done with dd. You can look at the exact code by checking the script /etc/daily.

However, it's not clear how to boot from this partition if you didn't install a bootloader or created an EFI partition on the disk...

OpenBSD manual pages: hier (hier stands for file system hierarchy)

OpenBSD manual pages: daily

OpenBSD FAQ: Root partition backup

2.9. talk: local chat in the terminal §

OpenBSD comes with a program named "talk", this creates a 1 to 1 chat with another user, either on the local system or a remote one (setup is more complicated). This is not asynchronous, the two users must be logged in the system to use talk.

This program isn't OpenBSD specific and can be used on Linux as well, but it's so fun, effective and easy to setup I wanted to write about it.

The setup is easy:

# echo "ntalk		dgram	udp	wait	root	/usr/libexec/ntalkd	ntalkd" >> /etc/inetd.conf
# rcctl enable inetd
# rcctl start inetd

The communication happens on localhost on UDP ports 517 and 518, don't open them to the Internet! If you want to allow a remote system, use a VPN to encrypt the traffic and allow ports 517/518 only for the VPN.

The usage is simple, if you want alice and bob to talk to each other:

  • alice type talk bob, and bob must be logged in as well
  • bob receives a message in their terminal that alice wants to talk
  • bob type talk alice
  • a terminal UI appears for both users, what they write will appear on the top half of the UI, and the messages from recipient will appear on the half bottom

This is a bit archaic, but it works fine and comes with the base system. It does the job when you just want to speak to someone.

3. Conclusion §

There are interesting features on OpenBSD that I wanted to highlight a bit, maybe you will find them useful. If you know cool features that could be added to this list, please reach me!

Mounting video ram on Linux

Written by Solène, on 10 February 2024.
Tags: #linux

Comments on Fediverse/Mastodon

1. Introduction §

Hi, did you ever wonder if you could use your GPU memory as a mount point, like one does with tmpfs and RAM?

Well, there is a project named vramfs that allows you to do exactly this on FUSE compatible operating system.

In this test, I used an NVIDIA GTX 1060 6GB in an external GPU case connected with a thunderbolt cable to a Lenovo T470 laptop running Gentoo.

vramfs official GitHub project page

2. Setup §

Install the dependencies, you need a C++ compiler and OpenCL headers for C++ (the package name usually contains "clhpp").

Download the sources, either with git or using an archive.

Run make and you should obtain a binary in bin/vramfs.

3. Usage §

It's pretty straightforward to use, as root, run vramfs /mountpoint 3G to mount a 3 GB storage on /mountpoint.

The program will stay in foreground, use Ctrl+C to unmount and stop the mount point.

4. Speed test §

I've been doing a simple speed test using dd to measure the write speed compare to a tmpfs.

The vramfs mount point was able to achieve 971 MB/s, it was CPU bound by the FUSE program because FUSE isn't very efficient compared to a kernel module handling a file system.

t470 /mnt/vram # env LC_ALL=C dd if=/dev/zero of=here.disk bs=64k count=30000
30000+0 records in
30000+0 records out
1966080000 bytes (2.0 GB, 1.8 GiB) copied, 2.02388 s, 971 MB/s

Meanwhile, the good old tmpfs reached 3.2 GB/s without using much CPU, this is a clear winner.

t470 /mnt/tmpfs # env LC_ALL=C dd if=/dev/zero of=here.disk bs=64k count=30000
30000+0 records in
30000+0 records out
1966080000 bytes (2.0 GB, 1.8 GiB) copied, 0.611312 s, 3.2 GB/s

5. Limitations §

I tried to use the vram mount point as a temporary directory for portage (the Gentoo tool building packages), but it didn't work due to an error. After this error, I had to umount and recreate the mount point otherwise I was left with an irremovable directory. There are bugs in vramfs, no doubts here :-)

Arch Linux wiki has a guide explaining how to use vramfs to store a swap file, but it seems to be risky for the system stability.

ArchWiki: Swap on video

6. Conclusion §

It's pretty cool to know that on Linux you can do almost what you want, even store data in your GPU memory.

However, I'm still trying to figure a real use case for vramfs except that it's pretty cool and impressive. If you figure a useful situation, please let me know.

Hosting Shaarli on OpenBSD

Written by Solène, on 19 January 2024.
Tags: #php #openbsd #rss

Comments on Fediverse/Mastodon

1. Introduction §

This guide explains how to install the PHP web service Shaarli on OpenBSD.

Shaarli is a bookmarking service and RSS feed reader, you can easily add new links and associate a text / tag and share it with other or keep each entry private if you prefer.

Shaarli GitHub Project page

2. Setup §

The software is pretty easy to install using base system httpd and PHP (included latest version available as of time of writing).

2.1. Deploy Shaarli §

Download the latest version of Shaarli available on their GitHub project.

Shaarli releases on GitHub

Extract the archive and move the directory Shaarli in /var/www/.

Change the owner of the following directories to the user www. It's required for Shaarli to work properly. For security’s sake, don't chown all the files to Shaarli, it's safer when a program can't modify itself.

chown www /var/www/Shaarli/{cache,data,pagecache,tmp}

2.2. Install the packages §

We need a few packages to make it work, I'm using php 8.3 in the example, but you can replace with the current version you want:

pkg_add php--%8.3 php-curl--%8.3 php-gd--%8.3 php-intl--%8.3

By default, on OpenBSD the PHP modules aren't enabled, you can do it with:

for i in gd curl intl opcache; do ln -s "/etc/php-8.3.sample/${i}.ini" /etc/php-8.3/ ; done

Now, enable and start PHP service:

rcctl enable php83_fpm
rcctl start php83_fpm

If you want Shaarli to be able to do outgoing connections to fetch remote content, you need to make some changes in the chroot directory to make it work, everything is explained in the file /usr/local/share/doc/pkg-readmes/php-INSTALLED.VERSION.

2.3. Configure httpd §

This guide won't cover the setup for TLS as it's always the same procedure, and it may depend on how you prefer to generate the TLS certificates.

Create the file /etc/httpd.conf and add the following content, make sure to replace all the caps text with real values:

server "YOUR_HOSTNAME_HERE" {
    listen on * port 80

    # don't rewrite for assets (fonts, images)
    location "/tpl/*" {
        root "/Shaarli/"
    }

    location "/doc/*" {
        root "/Shaarli/"
    }

    location "/cache/*" {
        root "/Shaarli/"
    }

    location "*.php" {
        fastcgi socket "/run/php-fpm.sock"
        root "/Shaarli"
    } 

    location "*index.php*" {
        root "/Shaarli"
        fastcgi socket "/run/php-fpm.sock"
    } 

    location match "/(.*)" {
        request rewrite "/index.php%1"
    }

    location "/*" {
        root "/Shaarli"
    }
}

Enable and start httpd

rcctl enable httpd
rcctl start httpd

2.4. Configure your firewall §

If you configured PF to block by default, you have to open the ports 80 and also 443 if you enable HTTPS.

3. Installing Shaarli §

Now you should have a working Shaarli upon opening http://YOUR_HOSTNAME_HERE/index.php/, all lights should be green, and you are now able to configure the instance as you wish.

4. Conclusion §

Shaarli is a really handy piece of software, especially for active RSS readers who may have a huge stream of news to read. What's cool is the share service, and you may allow some people to subscribe to your own feed.

This blog is AI free

Written by Solène, on 18 January 2024.
Tags: #ai #blog #life

Comments on Fediverse/Mastodon

1. Introduction §

Hi! This is a short informative blog post about Artificial Intelligence.

I just got approached by a company who wants to help me to add some generative AI in my blog workflow to "boost the quality" of my content.

I like generative AI and I think it's an interesting tool, but I have just no interest using it for my blog.

2. This blog content is made by a human §

We need some kind of label "not AI powered" :D I'll add something like that on my template

There is one exception as I wrote one blog post about machine learning, and obviously the pictures in it were generated/colored by a program to demonstrate the tools.

3. Why no AI? §

I have no incentive adding an AI in the process of writing, I do mistakes, I may make poor sentences and I have my own style for the best of the worst. I think throwing an AI into this would just make the result bland.

For a pretty similar reason, I keep my custom website generator and template instead of using a program like Hugo with an awesome template because I need to have this "authentic" feeling for my blog.

This blog is my own space, it represents who I am.

Overcoming imposter syndrome in IT

Written by Solène, on 10 January 2024.
Tags: #life

Comments on Fediverse/Mastodon

1. Introduction §

You certainly know about the Imposter Syndrome (I'll refer to it as IS), unfortunately it's a very common problem in IT.

Wikipedia: Imposter Syndrome

Imposter Syndrome explained in picture
Imposter Syndrome explained in picture

The picture above was downloaded from https://mrscliffnotes.com/2021/03/02/on-the-imposter-syndrome/

As I finally (almost) got rid of my own Imposter Syndrome, I wanted to share my experience and tips that helped me overcome it.

2. Keeping track of your work and knowledge §

It's hard to stay confident in your own skills when you feel you accomplished nothing in your life or career. I would recommend everyone to always keep a very detailed CV/Résumé up-to-date, with all the projects you worked on. When you feel in doubt about your own skills, just check this list, and you will certainly be surprised about what you achieve in the past.

If you are a developer, looking at your projects histories in git/mg/svn/whatever is also a nice way to review your own past work. There are dedicated git tools to write such nice reports, even across multiple repositories.

When I look back at my blog index, I realize how many things I learned. I forgot about most of the previous content and topics I wrote about! This is my own list, it's really helpful to me.

3. Meet other professionals §

It seems IS exists because it's hard to differentiate "low value general knowledge" and what we know and should know as a technician, knowledge that makes us a professional in our job. In IT it's really hard to evaluate a work/product/service, compared to let's say, a sculpted piece of wood. I'm not saying sculpting wood is easy, but at least it doesn't require an audit by a dedicated team to know if it was nicely done in the state of the art.

My confidence got better when I started spending time with the new colleagues when joining a new company. Being able to know how the other worked helped me to evaluate my own work, it was also the opportunity to ask them to review my work and methods. Honest feedback from a competent person is invaluable.

By spending more time with my colleagues, I was finally able to establish some kind of reference to auto-evaluate my work more accurately.

Moving to a new job is also the opportunity to meet real slackers with poor skills, and in most cases you will notice they don't even care. After all, if they got a job and their boss is happy, your work will just be better, so there is no reason to not stay confident in yourself.

4. Stay confident §

This seems boring and obvious, but you need to stay confident in yourself to start building some confidence. If you succeeded in a project in the past, there is no reason for you to fail in another project later.

Being able to overcome failures is an important part of the process. It's common for anyone to fail at something, but instead of lamenting about it, see it as the opportunity to improve yourself for the next time. There is a lot more to learn from failures than from successes.

5. Tip of the Iceberg §

When you see someone's work/article/video, you may be impressed by it and feel bad that you would never be able to achieve something similar because it's "too hard". But did you ever think that you only saw the tip of the iceberg, and that you dismissed all the hard work and researches done in order to succeed?

For instance, maybe that person spent hundreds of hours making a two minutes video: the result looks incredible to you, and it's only two minutes, so you immediately think "I would never be able to do this myself", but what if you had hundreds hours and the skills to do it? Could you?

6. Do they know? §

If you ever feel bad listening to someone's story that makes you feel incompetent and useless, you could think: "do they know how to do [this], and [this]?". ([this] being someone you know)

Yes, they are a programming compiler expert, but do they know like me how to cook? Do they know how to change a car wheel? Do they know how to grow vegetables?

7. Conclusion §

I'm not a psychologist, a personal coach or an imposter syndrome specialist. But I've been able to work around it, and I'm now gradually getting rid of it for good. It's really refreshing!

It's important to not feel over-confident in the process, there is a balance to keep, but don't think about it too early ;)

Have fun, you are awesome in your own way, like everyone else!

2024 plans and 2023 retrospective

Written by Solène, on 09 January 2024.
Tags: #life #blog

Comments on Fediverse/Mastodon

1. Hello! §

It happens that I occasionally write a blog post to give some news about my own projects and life(style), this is such a blog post!

2. 2023's projects §

2023 was a special year for me, I've been terribly sick early January, and this motivated me to change a lot of things in my life. I stuck to this idea the whole year and I still continue to lurk for changing things in my life.

2.1. Work §

I left the company I was working for, and started to work as a freelance DevSecOps/DevOps. The word "Sysadmin" would be the best job title for me, but people like buzzwords and nobody talk about system administrators anymore.

Since the end of the year, I also work as a technical writer for a VPN provider (that I consider ethical), and it makes me think that in the future, I may have a career shift to being a technical writer "only".

2.2. The blog §

Since 2023, I have a page on Patreon allowing my readers to support me financially, in exchange for a few days of early access for most blog posts. This is an advantage to reward my supporters without being a loss for all other readers. Patreon helps me a lot as it allows me to plan on a monthly income and spend more time on my blog or contributing to open source projects. I also added other payments option as some wanted to support me using more free (as in freedom) methods like liberapay, BTC or XMR.

The blog also received a few technical changes, mostly in the HTML rendering like captions on pictures or headers numbering. I'm quite pleased with the result right now, and the use of GemText (from Gemini) markup was a right choice a few years ago as it gives a simple structure enforcing clarity (of course it's bad if you need a complex layout).

The content finally got a proper license: CC-BY-4.0, I'm an open source person, but my own content was under no license, what a shame for all this time...

2.3. Open Source §

Last year, I started using Qubes OS as it's the best operating system for my needs (a blog post will cover this "soon") and I got involved into the community and in testing the 4.2 release that got out a few weeks ago by now.

I'm still contributing to OpenBSD, but not as much as I want, simply because of lack of hardware (and a bit of time), but this is now solved after my deal with NovaCustom. I still maintain the packages updates build cluster.

In 2023, I entirely dropped NixOS, but I preferred to not write a blog post about it to avoid a flame war, but maybe I'll write one. In a few words, I didn't like the governance issues of the project, it seems company driven to me and from my point of view it's harmful for the open source project. The technology is awesome, but the "core team" struggles to get somewhere. I'll investigate more Guix as I always enjoyed this project, and they proved they are a reliable and solid project able to maintain their pace over time.

2.4. The OpenBSD Webzine §

It's my favorite pet project, even though it's a lot of work to publish a single issue.

Working with Prahou for the special Halloween issue was really fun as instead of writing the content, I had to give some direction to keep the issue on rails for being a Webzine issue, while being able to enjoy it like any other reader as I didn't make the content itself.

3. 2024's project §

3.1. Lifestyle §

For no reasons, I decided to experiment vegetarian diet up to end of February (I still eat eggs, milk, butter, cheese or rarely fish). I'm bad at cooking, I don't enjoy it much but mostly because I have no idea what to cook. This forces me to learn about new food and recipes I was not aware of. Buying a recipes book is definitely a must for this :-). I never really enjoyed meat, and it's possible that I may keep the vegetarian diet for a longer time.

3.2. Open source §

This is the year of the comeback on OpenBSD, I really enjoy contributing to it, helping the community and reviewing some ports I care of.

I'll also continue contributing to Qubes OS, this niche operating system deserves some more contributors.

3.3. The blog §

I'll try to stick to a weekly blog post schedule. Of course, I also need to work in parallel, and sometimes I'm just out of ideas :-)

3.4. Work §

Let's see what 2024 will bring for me!

4. Best wishes! §

I'd like to thank all my readers. I regularly receive emails about your enjoyments, or typos reports, or suggestions to improve the content, this really drives me continuing writing.

NovaCustom NV41 laptop review

Written by Solène, on 03 January 2024.
Tags: #openbsd #linux #qubesos #hardware

Comments on Fediverse/Mastodon

1. Disclaimer §

Hello! Today, I present you a quite special blog post, resulting from a partnership with the PC Manufacturer NovaCustom. I offered them to write an honest review for their product and also share my feedback as a user, in exchange for a NV41 laptop. This is an exceptional situation, I insist that it's not a sponsorship, I actually needed a laptop for my freelance work, and it turns they agreed. In our agreements, I added that I would return the laptop in the case I wouldn't like it, I don't want to generate electronic wastes and company's money for nothing.

I have no plans to turn my blog into an advertisement platform and do this on a regular basis. Stars aligned well here, NovaCustom is making the only modern laptop Qubes OS certified, and the CEO is a very open source friendly person.

2. Introduction §

The real introduction now :-)

In this blog post, I'll share my experience using a NV41 laptop from NovaCustom, I tried many operating systems on it for a while, run some benchmarks, and ultimately used Qubes OS on it for a month and half for my freelance work.

NovaCustom official website

NV41 Laptop store webpage

3. The machine itself §

The laptop on a stand, running Ubuntu 23.10
The laptop on a stand, running Ubuntu 23.10

This is a 14-inch laptop, the best form factor in my opinion for being comfortable when used for a long time while being easy to carry.

It looks great with its metal look with blueish reflection and the engraved logo "NV" on the cover (logo can be customized).

The frame feels solid and high-end, I'm not afraid to carry it or manipulate it. Compared to my ThinkPad T470, that's a change, I always fear to press its plastic frame too much when carrying with a single hand.

The power button is on the right side, this is quite unusual, but it looks great, there are LED around the power plug near the power button that tells the state of the system (running, off, sleeping) and if the battery is running low or charging.

It's running the open-source Firmware Dasharo coreboot, and optionally the security oriented firmware Heads can be installed.

Dasharo coreboot official website

Heads open source firmware official website

3.1. Packaging and unboxing §

The machine came in a box containing a box containing the actual box with the laptop inside, it was greatly packaged.

Laptop still wrapped in the protections, all the boxes are in the background
Laptop still wrapped in the protections, all the boxes are in the background

The laptop screen had a removable sleeve that can be reused, I appreciated this as it's smart because it's possible to put it back in case you don't use the laptop for a long time or want to sell it later.

The box contained the laptop, the power supply and the power plug, the full length of the power supply is 2 meters which is great, I hate laptops chargers that only have 1 meter of cable.

The laptop, power supply, power plug and other (manual, screen cleaner…)
The laptop, power supply, power plug and other (manual, screen cleaner…)

3.2. Hardware §

The specifications of the hardware I received are the following:

  • CPU: i7-1260P (4 Performance cores with hyper-threading, 8 Efficient cores)
  • Memory: 2x32 GB of 3200 MHz
  • Storage: NVME Samsung 980 Pro 2 TB
  • Wireless: blob-free Atheros QCNFA222 Wi-Fi a/b/g/n + bluetooth 4.0
  • Screen: 14" 1080p (1920x1080), 98% sRGB 60 Hz, anti-glare treatment
  • Weight: 1.4 kg

The default wireless card is an Intel AX-200/201 compatible with Wi-Fi 6 and Bluetooth 5.2, but I received the blob-free card which was convenient for most operating systems as it doesn't need a firmware (works out of the box on Guix for instance).

There are options to remove the webcam or add a slider to it, a screen privacy filter or secure screws+tape for the packaging to be sure the laptop hasn't been intercepted during transit.

You can also choose the keyboard layout from a large list, or even have your own layout.

Kudos to NovaCustom for guaranteeing the sell of replacement parts for at least 7 years after you buy them a laptop! They also provide a PDF will full details about the internals.

3.2.1. Hybrid CPU §

This is my very first Hybrid CPU, it has 4 Performance cores capable of hyperthreading, and 8 Efficient cores that should draw less power at the expense of being slower.

I made a benchmark, only on Qubes OS, to compare the different cores to a Ryzen 5 5600X and my T470 i5-7300U.

Phoronix benchmark link

Qubes OS forum: Hybrid CPU benchmarking performance when pinning to specific cores

If your operating system doesn't know (Linux does) how to make use of E/P cores (like OpenBSD or FreeBSD), it will use them like if they were similar, so no worry here. However, the performance and battery saving aren't optimized because the system won't balance the load at the right place.

TL;DR: the P cores compete with my desktop Ryzen 5 5600X! And the E cores are faster than the i5-7300U! Linux and Xen (in Qubes OS) does a great job at balancing the workload at the right place, so you don't have to worry about pinning a specific task to a P or E core pool.

3.2.2. Coil whine noise §

I think this deserves an entry because it's a plague on many modern computers. If you don't know about it, it's an electric noise that happens under certain conditions. On my T470, it's when charging the battery.

I've been able to get some coil whine noise, only if I forced the CPU frequency to the maximum in the operating system, instead of letting the computer scaling the frequency. This resulted in no performance improvement and some coil whine noise.

In my daily "normal" use with Linux or Qubes OS, I never heard a coil whine. But on OpenBSD for which the frequency management is still not good with these modern CPUs (intel p-state support isn't great) there is a constant noise. However, using obsdfreqd reduced the noise to almost nothing, but still appeared a bit on CPU load.

There is a specific topic where coil whine on this laptop was discussed, a fix was provided by NovaCustom using heat pads (sent for free for their customers) placed at a specific place. I don't think this should be required except if your operating system has a poor support for frequency scaling.

Qubes OS forum: NV41 coil whine topic

3.2.3. Screen §

The screen coloring is excellent, which is expected as it covers 98% of sRGB palette, it's really bright, and I rarely turn the brightness more than 50%. I didn't try to use it outdoor, but the brightness at full level should allow reading the screen.

However, it has a noticeable ghosting which make it annoying for playing video games (that's not really the purpose of this model though), or if you are really sensitive to it. I'm used to a 144 Hz display on my desktop and I became really sensitive to refresh rate. However, I have to admit the ghosting isn't really annoying for productivity work, development or browsing the web. Watching a video is fine too.

One slightly annoying limitation is that it's not possible to open the screen more than a 140° angle, this sounds reasonable, but I got used to my T470 screen able to open at ~180°. This is not a real issue, but if you have a weird setup in which you store your laptop vertically against your desktop AND with the screen opened, you won't be able to use the screen.

3.2.4. Sound system §

I've been surprised by the speakers, the audio quality is good up to ~80% of the max volume, but then the quality drops when you set it too high.

I have no way to measure it, but the speakers appear to be quite loud compared to my other laptops when set to 100%, I don't recommend doing it though due to quality drop, but it can be handy sometimes.

The headphones port works fine, there are no noises, and it's able to drive my DT 770 Pro 80 ohm.

I’ve been able to figure an equalizer setting improving the audio to be pretty good (that's subjective). I’m absolutely not an audio expert, but it sounded a lot better for pop, rock, metal or piano.

  • 31 Hz: 0 db
  • 63 Hz: 0 db
  • 125 Hz: 0 db
  • 250 Hz: 0 db
  • 500 Hz: -4 db
  • 1 kHz: -5 db
  • 2 kHz: -8 db
  • 4 kHz: -3 db
  • 8 kHz: -3 db
  • 16 kHz: +2 db

The idea is to lower the trebles instead of pushing the bass which quickly saturate. Depending on what you listen to and your tastes, you could try +1 or +2 db for the four first settings, but it may produce saturated sounds.

3.2.5. Cooling §

I think the cooling system is one of the best part of the laptop, it's always running at 10% of its speed and is inaudible.

Laptop view from below
Laptop view from below

Under a huge load, the fan can be heard, but it's still less loud than my idling silent desktop...

There is a special key combination (Fn+1) that triggers the turbo fan mode, forcing them to run at 100%, it is recommended if the laptop is used to run at full CPU 24/7 or for a very long period of time, however, this is as loud as a 1U rack server! For a more comprehensive comparison, let's say it is as annoying as a microwave device.

I was surprised that the laptop never burned my knees, although under heavy load for 30 minutes it felt a bit too hot to keep it on my bare skin without fabric between, that's a genuine lap-top laptop, compatible with short skirts :D.

3.2.6. Keyboard §

The keyboard isn't bad, but not good either. Typing on it is pleasant, but it's no match against my mechanical keyboards. The touch is harder than on my Lenovo T470 laptop, I think it feels like most modern laptop keyboards.

Check the layout for the keys like "home", "end", "page up/down", on mine they are tiny keys near the arrows, this may not be to your taste.

The type is quite silent, and there are 5 levels of back-light, I don't really like this feature, so I turned it off, but it's there if you like it.

There are NO indicators for the status of caps lock or num lock (neither for scroll lock, but do people really use it?), this can be annoying for some users.

3.2.7. Touchpad §

The touchpad may be a no-go for many, there are no extra physical buttons but you can physically click on the bottom area to make/hold a click. It also features no trackpoint (the little joystick in the middle of the keyboard).

However, it has a large surface and can make use of multitouch clicks. While I was annoyed at first because I was used to ThinkPad's extra physical buttons, over time I got used to multitouch click (click is different depending on the number of fingers used), or the "split-area" click, where a click in a bottom left does a left click, in the middle it does a middle click, and in the bottom right it does a right click.

It reacts well to movements and clicks and does the job, it's not the greatest touchpad I ever used, but it's good enough.

Unfortunately, it's not possible for NovaCustom to propose a variant touchpad featuring extra physical buttons.

3.2.8. Suspend and Resume §

The suspend/resume feature works as expected on Linux and Qubes OS.

Closing the lid correctly triggers the suspend function, opening it resumes the system.

3.2.9. Webcam §

Nothing special to say about it, it's like most laptop webcams, it has a narrow angle and the image quality is good enough to show your face during VoIP meetings.

3.2.10. Battery life (short version) §

I tested the battery using different operating systems (OpenBSD, Qubes OS, Fedora, Ubuntu) and different methods, there are more details later in the text, but long story short, you can expect the following:

  • battery life when idling: 6h00
  • battery life with normal usage: 3h00-5h00 for viewing videos, browsing the web, playing emulated games, code development and some compilation
  • battery life in continuous heavy use: 2h00 (I accidentally played a long video with no hardware-acceleration, it was using 500% CPU)

3.2.11. I/O ports §

On the I/O, the laptop is well-equipped. I appreciated seeing an Ethernet port on a modern laptop.

On the left side:

  • 1x Thunderbolt 4 / USB-c (supports external screen and charging)
  • 1x USB
  • anti-thief system
  • Ethernet port
  • Multi-card reader (a SD card plugged in doesn't go completely inside, so it's not practical for a persistent extra storage)
Left side of the laptop
Left side of the laptop

On the right side:

  • 1x USB-c (supports external screen)
  • 1x headphone
  • Charge port
  • Power button and two discrete states LEDs
  • 1x HDMI
  • 1x USB
Right side of the laptop
Right side of the laptop

The rear of the laptop is fully used for the cooling system, and there are nothing on the front (Hopefully! I hate connecting headphones on the front side).

Back of the laptop
Back of the laptop
Front of the laptop
Front of the laptop

3.3. Dasharo coreboot firmware §

The laptop ships by Dasharo coreboot firmware (that's the correct name for nowadays devices when we speak of the BIOS), it's an open-source firmware that allows to manage your own secure boot keys, disable some Intel features like "ME"

I guess their website will be a better place to understand what it's doing compared to a proprietary firmware.

Dasharo official website

3.4. NovaCustom §

NovaCustom is building laptops based on Clevo (a manufacturer doing high-end laptop frames, but they rarely sell directly) while ensuring compatibility with Linux systems, especially Qubes OS for this specific model as it's certified (it guarantees the laptop and all its features will work correctly).

They contribute to dasharo development for their own laptops.

They ship their product worldwide, and as I heard from some users, the custom support is quite reactive.

NovaCustom official website

4. Operating system support §

Now I shared about the hardware part, let's see how it behaves with many operating systems!

4.1. Linux distributions §

I guess most users will use a Linux system on this laptop, so let's start by testing some popular distributions:

4.1.1. Fedora §

Fedora project official website

Screenshot of Fedora 39 running GNOME
Screenshot of Fedora 39 running GNOME

Fedora Linux support (tested with Fedora 39) was excellent, GNOME worked fine. The Wi-Fi network worked immediately even during the installer, Bluetooth was working as well with my few devices. Changing the screen brightness from the GNOME panel was working. However, after a Dasharo update, the keyboard slider in GNOME stopped working, it's a known bug that also affects System76 laptops if I've read correctly, this may be an issue with the Linux driver itself.

The touchpad was working on multitouch out of the box, suspending and resuming the laptop never produced any issue.

Enabling Secure Boot worked out of the box with Fedora, which is quite enjoyable.

4.1.2. Ubuntu §

Ubuntu company official website

Ubuntu 23.10 support was excellent as well, it's absolutely identical to the Fedora report above.

Note: if you use VLC from the Snap store, it won't have hardware decoded acceleration and will use a lot of CPU (and draw battery, and waste watts for nothing), I guess it's an Ubuntu issue here. VLC from Flatpak worked fine, as always.

4.1.3. Alpine Linux §

Alpine Linux project official website

Alpine Linux support (tested with Alpine 3.18.4) was excellent, I installed GNOME and everything worked out of the box. The Atheros card worked without firmware (this is expected for a blob free device), CPU scheduling was correctly handled for Efficient/Performance cores as the provided kernel is quite recent.

The touchpad default behavior was to click left/right/middle depending on the number of fingers used to click, suspend and resume worked fine, playing video games was also easy thanks to flatpak and Steam.

It's possible to enable Secure Boot by generating your own keys.

Alpine Linux wiki: UEFI Secure Boot

4.1.4. Guix §

Guix project official website

Screenshot of Guix running GNOME
Screenshot of Guix running GNOME

Guix support is mixed. I've been able to install it with no issue, thanks to the blob-free atheros network interface, it worked without having to use guix-nonfree repository (that contains firmware).

However, I was surprised to notice that the graphical acceleration wasn't working, it seems that Intel Xe GPU aren't blob free. This only mean you can't plan video games or that any kind of GPU related encoding/decoding won't work, but this didn't prevent GNOME to work fine.

Suspend and resume was OK, and the touchpad worked out-of-the-box in multi-tap mode.

Secure Boot didn't work, and I have no idea how a Secure Boot setup with your own keys would look like on Guix, but it's certainly achievable with enough Grub-foo.

4.1.5. Trisquel §

Trisquel GNU/Linux official project website

Trisquel is a 100% libre GNU/Linux distribution, this mean it doesn't provide proprietary software or drivers, and no device firmware.

I've been able to install Trisquel and use it, the Wi-Fi was working out of the box because of the blob-free Atheros card.

The main components of the system: CPU / Memory / Storage were correctly detected, the default kernel isn't too old, and it was able to make use of the Efficient/Performance core of the CPU.

When not using the laptop, I was able to suspend it to reduce the battery usage, and then resume instantly the session when I needed, this worked flawlessly.

The touchpad was working great using the "3 zones" mode in which you tap on the touchpad in the left/center/right bottom of it to make a left/middle/right click, this is actually as convenient as using 1, 2 or 3 fingers depending on the click you want to make, this is something that could be configured though.

Sound was working out of the box, the audio jack is also working fine when plugging in headphones.

There is one issue with the webcam, when trying to use it, X crashes instantly. This may be an issue in Trisquel software stack because it works fine on other OS.

A major issue right now is the lack of graphical hardware acceleration, I'm not sure if it's due to the i7-1260P integrated GPU needing a proprietary firmware or if the linux-libre kernel didn't catch up with this GPU yet.

4.2. Qubes OS §

Qubes OS project official website

Qubes OS 4.2 desktop screenshot
Qubes OS 4.2 desktop screenshot

Qubes OS support (tested with 4.1, 4.2-RC2 to RC5 and 4.2) is excellent, this is exactly what I expected for a Qubes OS certified laptop (the only modern and powerful certified laptop as of January 2024!).

Qubes OS documentation: Hardware certification requirements

Qubes OS is my main OS as I use it for writing this blog, for work (freelancer with different clients) and general use except gaming, so I needed a reliable system that would be fast, with a pretty good battery life.

So far, I never experienced issues except one related to the Atheros Wi-Fi card (this is not the stock Wi-Fi device): 1 time out of 10 when I suspend and resume, the card is missing, and I need to restart the qube sys-net to have it again. I didn't try with the latest Dasharo update though, it may be solved.

Watching 1080p videos x265 10 bits encoded is smooth and only draw ~40% of a CPU, without any kind of GPU accelerated decoding.

The battery life when using the system to write emails, browse the Internet and look at some videos was of 3 hours, if I only do stuff in LibreOffice offline it lasts 5h30.

I'm able to have smooth videoconferences with the integrated webcam and a USB headset, this kind of task may be the most CPU consuming popular job that Qubes OS need, and it worked well.

The 64 GB are very appreciated, I "only" have 32 GB on my desktop computer, but sometimes it lacks memory... 64 GB allows to not ever think about memory anymore.

The touchpad is working fine, by default on the split-area behavior (left/middle/right click depending on the touchpad area you click on).

There is a single USB controller that drives the webcam and card reader + the USB ports, including a USB-c docked that would be connected on either the thunderbolt or USB-c ports. The thunderbolt device is on a separate controller, but if you attach it to a qube (that is not sys-usb), you lose all USB connectivity from a dock connected to it (there is still the other plain USB-c port). The qube sys-usb isn't even required to run if you don't use any USB devices (this saves many headaches and annoying times).

Connecting a usb-c dock on the thunderbolt port allows to have USB passthrough with sys-usb, an additional ethernet port and external screen working with sound, it's also capable of charging the computer. Whereas the simple usb-c port can only carry USB devices or the integrated ethernet port of my dock, it should be able to support a screen but I guess it's not working on Qubes OS. I didn't try adding more than one screen on either ports, I guess it should work on the thunderbolt port.

4.3. BSD systems §

I tried OpenBSD and FreeBSD with the laptop. I always have bad luck with NetBSD, so I preferred to not try it, and DragonFly BSD support should be pretty close to FreeBSD for which it didn't work well.

4.3.1. OpenBSD §

OpenBSD project official website

Screenshot of the OpenBSD 7.4 desktop using GNOME
Screenshot of the OpenBSD 7.4 desktop using GNOME

I tried OpenBSD 7.4 and -current, everything went really well except the Atheros WiFi card that isn't supported, but this was to be expected. If you want the NV41 with OpenBSD, you need to take the Intel AX-200/201 which is supported by the iwx driver.

OpenBSD manual page: iwx(4)

Suspend and resume works fine, the touchpad is using the "3 zones" behavior by default where you need to tap left/center/right bottom to make a left/middle/right click. The webcam and sound card were working fine too.

The GPU is fully supported, you can use it for 3D rendering: I've been able to play a PSP game using PPSSPP emulator. OpenBSD doesn't support hardware accelerated video encoding/decoding at all, so I didn't test it.

WipeOut Pulse emulated in the PSP emulator PPSSPP
WipeOut Pulse emulated in the PSP emulator PPSSPP

4.3.2. FreeBSD §

FreeBSD project official website

I installed FreeBSD 14.0 RC4 with ZFS on root and full disk encryption, the process went fine, I had Wi-Fi at the installer step (thanks to the blob free Atheros card).

However, once I booted into the system, I didn't succeed to get X to run, the GPU isn't supported yet and using VESA display didn't work for me. Suspend and resume didn't work either.

I gave another try with GhostBSD 23.10.1 in hope I did something wrong on FreeBSD 14 RC4 like a misconfiguration as I never had any good experience with FreeBSD on desktop with regard to the setup. But GhostBSD failed to start X and was continuously displaying its logo on screen, only booting in safe mode allowed me to figure what was wrong.

I was really surprised that the hardware is still "too new" for FreeBSD while OpenBSD support is almost excellent.

4.4. Other §

Some less known operating systems were tested as well.

4.4.1. Haiku §

Haiku project official website

Photography of the laptop running Haiku (live USB)
Photography of the laptop running Haiku (live USB)

I booted Haiku revision 57370 live USB, I was actually surprised to have the desktop displayed, and the network interfaces recognized.

Unfortunately, the Atheros card was recognized, but I haven't been able to connect to a scanned network.

The display was using the correct resolution, but it was using software rendering.

The webcam and the touchpad didn't work, I had to connect my USB trackball.

I didn't go as far as installing it.

4.4.2. OpenIndiana §

I tried the freshly released OpenIndiana Hipster 2023.10 liveUSB.

After letting the bootloader display and start the boot process, the init process seemed stuck and was printing errors about CPU every minute. I haven't been able to get past this step.

5. Measurements §

I had fun measuring a lot of things like power usage at the outlet, battery duration with many workloads and gaming FPS (Frames per Second, 30 is okayish depending on people, 40 is acceptable, 60 is perfect as it's the refresh rate of the screen).

5.1. Power §

I measured the power usage in watts using a watt-o-meter in different situations:

  • power supply connected, but not to the laptop: 0 watt (some power supplies draw a few watts doing nothing... hello Nintendo Switch with its 2.1 watts!)
  • charging, sleeping: 30 watts
  • charging, idling: 37 watts
  • charging and heavy use: 79 watts
  • connected to AC (not charging), sleeping: 1 watt
  • connected to AC (not charging), idling, screen at full brightness: 17 watts
  • connected to AC (not charging), downloading a file over Wi-Fi, screen at full brightness: 22 watts

This is actually good in my opinion, to have a comparison point, a standard 24-inch screen usually draw around 40 watts alone.

The power consumption of the laptop itself is within the range of other laptop. I was happy to see it use no power when the AC is connected but not to the computer, and on idling it's only 1 watt, I have another laptop idling at 7 watts!

5.2. Battery life §

I measured the battery life using different methods and sometimes multiple times to verify if it was reliable.

5.2.1. Linux §

One method was to play a 2160p x265 10 bits encoded video using VLC, 1h39 long, with full brightness and no network.

  • With hardware accelerated decoding support: 33% of the battery was used, so the battery life would theoretically be almost 6 hours (299 minutes) while playing a video at full brightness
  • Without hardware acceleration: 90% of the battery was used (VLC was using 480% of the CPU, but I didn't notice it as the fans were too silent!), this would mean a battery life of 1h49 (110 minutes) using the computer under heavy load

The other method was to play the video game "Risk of Rain Returns" with a USB PS5 controller, and at full brightness, for a given duration (measured at 20 25 minutes).

  • Risk of Rain Returns: 15% of battery used in 20 minutes, this mean I should have been able to play 2h13 (133 minutes) before having to charge.

5.2.2. OpenBSD §

I played a PSP game for 25 minutes using PPSSPP in full screen at full brightness.

  • WipeOut Pulse: 14% of battery was used in 25 minutes, this mean I could have played for almost 3 hours straight (178 minutes)

5.3. Gaming performance §

I did play a bit on the laptop on Linux using Steam on Flatpak. I tested it on Fedora 39, Ubuntu 23.10 and Alpine Linux 3.18.3, results were identical.

A big surprise while playing was that the fans remained almost silent, they were spinning faster than usual of course, but that didn't require me to increase the moderate volume I used in my gaming session.

  • Baldur's Gate 3: Playable at stable 30 FPS with all settings to low and FSR2.2 enabled in ultra performance mode
Baldur
Baldur's Gate 3 (2023)
  • Counter Strike 2: Stable 60 FPS in 1600x900 with all settings set to minimum
Counter Strike 2
Counter Strike 2
  • Spin Rhythm XD: Stable at 60 FPS
  • Rain world: Stable at 60 FPS
  • HELLDIVERS: Stable at 60 FPS with native resolution and graphical settings set to maximum
  • Beam NG;Drive: Playable with a mix of low/normal settings at 30 FPS
  • Resident Evil: Solid 45 FPS with the few settings set to maximum, better lock the game at 30 FPS though
  • Risk of Rain Returns: Stable 60 FPS
Risk of Rain returns
Risk of Rain returns
  • Risk of Rain 2: Stable 60 FPS using 1600x900 with almost all settings to lowest
Risk of Rain 2
Risk of Rain 2
  • Endless Dungeon: with the lowest settings and resolution lowered to 1600x900, it was able to maintain stable 30 FPS, it was kinda playable

I didn't try using an external GPU on the thunderbolt port, but you can expect way better performance as the games were never CPU bound.

6. Conclusion §

I'm glad I dared asking NovaCustom about this partnership about the NV41, this is exactly the laptop I needed. It's reliable, no weird features, it's almost full open source (at least for the software stack?), very powerful, and I can buy replacement parts for at least 7 years if I break something. It's also SILENT, I despise laptop having a high pitch fan noise.

I still have to play with Dasharo coreboot, I'm really new to this open-source firmware world, so I have to learn before trying weird and dangerous things (I would like to try Heads for its anti-evil maid features, it should be possible to install it on Dasharo systems "soon").

Writing this blog post was extremely hard, I had to stay mindful that this must be an HONEST and NEUTRAL review: writing about a product you are happy with leads to some excitement moments and one may forget to share some little annoyance because it's "not _that_ bad", but I did my best to stay neutral when writing. And this is the agreement I had with NovaCustom.

Honesty is an important value to me. You, dear readers, certainly trust me to some point, I don't want to lose your trust.

OpenBSD workstation hardening

Written by Solène, on 31 December 2023.
Tags: #security #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to share a list of hardening you can do on your OpenBSD workstation, and explaining the threat model of each change.

OpenBSD official project website

Feel free to pick any tweak you find useful for your use-case, many are certainly overkill for most people, but depending on the context, these changes could make sense for others.

2. User configuration §

There are some tweaks that could be done in the configuration of a user to improve the security.

2.1. The Least privileges §

In order to prevent a program to escalate privileges, remove yourself from the wheel group, and don't set any doas or sudo permission.

If you need root privileges, switch to a TTY using the root user.

2.2. Multiple-factor authentication §

In some cases, it may be desirable to have a multiple factor authentication, this mean that in order to log in your system, you would need a TOTP generator (phone app typically, or a password manager such as KeePassXC) in addition to your regular password.

This would protect against people nearby who may be able to guess your system password.

I already wrote a guide explaining how to add TOTP to an OpenBSD login.

Blog post: Multi-factor authentication on OpenBSD

2.3. Home directory permission §

The permissions of the user directory should be 700, so only the owner and root could browse it.

Ideally, you should add umask 077 to your user environment, so every new directory or file permissions will be restricted to your user only.

3. Firewall §

There are some interesting policies to configure with the help of OpenBSD firewall Packet Filter.

3.1. Block inbound §

By default, it's good practice to disable all incoming traffic except the responses to established sessions (so servers can reply to your requests). This protects against someone on your local network / VPN to access network services that would be listening on the network interfaces.

In /etc/pf.conf you would have to replace the default:

block return
pass

By the following:

block all
pass out inet
# allow ICMP because it's useful
pass in proto icmp

Then, reload with pfctl -f /etc/pf.conf, if you ever need to allow a port on the network, add the according rule in the file.

3.2. Filter outbound §

It may be useful and effective to block outbound traffic, but this only work effectively if you know exactly what you need because you will have to allow hosts and remote ports manually.

It would protect against a program trying to exfiltrate data using a non-allowed port/host.

4. Disabling network for the desktop user §

Disabling network by default is an important mitigation in my opinion. This will protect against any program your run and try to act rogue, if they can't figure there is a proxy, they won't be able to connect to the Internet.

This could also save you from mistaken commands that would pull stuff from the network like pip, npm and co. I think it's always great to have a tight control on which program should do networking and which shouldn't. On Linux this is actually easy to do, but on OpenBSD we can't restrict a single program so a proxy is the only solution.

This can be done by creating a new user named _proxy (or whatever the name you prefer) using useradd -s /sbin/nologin -m _proxy and adding your SSH key to its authorized_keys file.

Add this rule at the end of your file /etc/pf.conf and then reload with pfctl -f /etc/pf.conf:

block return out proto {tcp udp} user solene

Now, if you want to allow a program to use the network, you need to:

  • toggle the proxy ON with the command: ssh -N -D 10000 _proxy@localhost which is only possible if your SSH private key is unlocked
  • configure a SOCKS5 proxy in the program

4.0.1. Some network fixes §

Most programs will react to a proxy configured in a variable named http_proxy or https_proxy or all_proxy, however it's not a good idea to globally define these variables for your user as it would be a lot easier to a program to use the proxy automatically, which is against the essence of this proxy.

4.0.1.1. SSH §

By default, you won't be able to ssh to anything except on a local user, we need to proxy every remote ssh connection through the local _proxy user.

In ~/.ssh/config:

Host localhost
User _proxy
ControlMaster auto
ControlPath ~/.ssh/%h%p%r.sock
ControlPersist 60

Host *.*
ProxyJump localhost

4.0.1.2. Chromium §

If you didn't configure GNOME proxy settings, Chromium / Ungoogled Chromium won't use a proxy, except if you add a command line parameter --proxy-server=socks5://localhost:10000.

I tried to manually modified the dconf database where the "GNOME" settings are to configure the proxy, but I didn't get it to work (it used to work for me, but I can't succeed anymore).

4.0.1.3. Syncthing §

If you use syncthing, you need to proxy all its traffic through the SSH tunnel. This is done by setting the environment variable all_proxy=socks5://localhost:10000 in the program environment.

5. Live in a temporary file-system §

It's possible to have most of your home directory be a temporary file system living in memory, with a few directories with persistency.

This change would prevent anyone from using temporary files or cache left-over from previous session.

The most efficient method to achieve this is to use the program home-impermanence that I wrote for this use case, it handles a list of files/directories that should be persistent.

Blog post: Reproducible clean $HOME on OpenBSD using impermanence

If you only want to start fresh using a template (that doesn't evolve on use), you can check the flag -P of mount_mfs which allows populating the fresh memory based file system using an existing directory.

OpenBSD man page: mount_mfs(8)

6. Disable webcam and microphone §

Good news! I take the opportunity here to remember OpenBSD disables by default the video and audio recording of the various capable devices, instead, they will appear to work but record empty stream of data.

They can be manually enabled by changing the sysctls kern.audio.record or kern.video.record to 1 when you need to use them.

Some laptop manufacturer offer the option to have a physical switch to disable microphone and webcam, so you can be confident about their state (Framework). Some other manufacturer also allow to not put any webcam and microphone (NovaCustom, Nitropad). Finally, open source firmwares like Coreboot can offer a bios setting to disable these peripherals, it should be trustable in my opinion.

7. Disabling USB ports §

If you need to protect your system from malicious USB devices (usually in an office environment), you should disable them in the BIOS/Firmware if possible.

If it's not possible, then you could still disable the kernel drivers at boot time using this method.

Create the file /etc/bsd.re-config and add the content to it:

disable usb
disable xhci

This will disable the support for USB 3 and 2 controllers. On a desktop computer, you may want to use PS/2 peripherals in these conditions.

8. System-wide services §

8.1. Clamav antivirus §

While this one may make you smile, if there is a chance it saves you once, I think it's still a valuable addition to any kind of hardening. A downloaded attachment from an email, or rogue JPG file could still harm your system.

OpenBSD ships a fully working clamav service, don't forget to enable freshclam, the viral database updater.

8.2. Auto-update §

I already covered it in a previous article about anacron, but in my opinion, auto-updating the packages and base system daily on a computer is the minimum that should be done everywhere.

Anacron: useful OpenBSD examples

9. System configuration §

9.1. Memory allocation hardening §

The OpenBSD malloc system allows you to enable some extra checks, like use after free, heap overflow or guard pages, they can be all enabled at once. This is really efficient for security as most security exploits relies on memory management issues, BUT it may break software that have memory management issues (there are many of them). Using this mode will also impact the performance negatively, as the system needs to do more checks for each piece of allocated memory.

In order to enable it, add this to /etc/sysctl.conf:

vm.malloc_conf=S

It can be immediately enabled with sysctl vm.malloc_conf=S, and disabled by setting no value sysctl vm.malloc_conf="".

The program ssh and sshd always run with this flag enabled, even if it's disabled system-wide.

10. Some ideas to go further §

10.1. Specialized proxies §

It could be possible to have different proxy users, with each restriction to the remote ports allowed, we could imagine proxies like:

  • http / https / ftp
  • ssh only
  • imap / smtp
  • etc....

Of course, this is even more tedious than the multipurpose proxy, but at least, it's harder for a program to guess what proxy to use, especially if you don't connect them all at once.

10.2. Run process using dedicated users §

I wrote a bit about this in the past, for command line programs, running them in dedicated local users over SSH make sense, as long as it's still practical.

Dedicated users to run processes

But if you need to run graphical programs, this becomes tricky. Using ssh -Y gives the remote program a full access to your display server, which has access to everything else running, not great... You could still rely on ssh -X which enables X11 Security extensions, but you have to trust the implementation, and it comes with issues like no shared clipboard, poor performance and programs crashing when attempting to access a legit resource that is blocked by the security protocol...

In my opinion, the best way to achieve isolation for graphical programs would be to run a dedicated VNC server in the local user, and connect from your own user. This should be better than running on your own X locally.

10.3. Encrypted home with USB unlocking §

In a setup where the computer is used by multiple person, the system encryption may be tedious because everyone have to remember the main passphrase, you have no guarantee one won't write it down on a post-it... In that case, it may be better to have a personal volume, encrypted, for each user.

I don't have an implementation yet, but I got a nice idea. Adding a volume for a user would look like the following:

  • take a dedicated USB memory stick for this user, this will be used as a "key" to unlock their data directory
  • overwrite the memory stick with random data
  • create an empty disk file on the system, it will contain the encrypted virtual disk, use a random part of the USB disk for the passphrase (you will have to write down the length + offset)
  • write a rc file that looks for the USB disk volume if present, if so, tries to unlock and mount the partition upon boot

This way, you only need to have your USB memory stick plugged in when the system is booting, and it should automatically unlock and mount your personal encrypted volume. Note that if you want to switch user, you would have to reboot to unlock their drive if you don't want to mess with the command line.

11. Conclusion §

It's always possible to harden a system more and more, but the balance between real world security and actual usability should always be studied.

No one will use a too-much hardened system if they can't work on it efficiently, on the other hand, users expect their system to protect them against most common threats.

Depending on one's environment and threat model, it's important to configure their system accordingly.

Qubes OS backup transfer from old to new computer

Written by Solène, on 24 December 2023.
Tags: #security #qubesos #networking

Comments on Fediverse/Mastodon

1. Introduction §

With the recent release of Qubes OS 4.2, I took the opportunity to migrate to a newer laptop (from a Thinkpad T470 to a NovaCustom NV41) so I had to backup all the qubes from the T470 and restore them on the NV41.

The fastest way to proceed is to create the backups on the new laptop directly from the old one, which is quite complicated to achieve due to Qubes OS compartmentalization.

In this guide, I'll share how I created a qube with a network file server to allow one laptop to send the backups to the new laptop.

Qubes OS official project website

Of course, this whole process could be avoided by using a NAS or external storage, but they are in my opinion slower than directly transferring the files on the new machine, and you may not want to leave any trace of your backups.

2. Explanation about the setup §

As the new laptop has a very fast NVME disk, I thought it would be nice to use it for saving the backups as it will offload a bit of disk activity for the one doing backups, and it shouldn't be slowed down during the restore process even if it has to write and read the backups at the same time.

The setup consists in creating a dedicated qube on the new laptop offering an NFS v4 share, make the routing at the different levels, and mount this disk in a qube on the old laptop, so the backup could be saved there.

I used a direct Ethernet connection between the two computers as it allows to not think much about NFS security

3. Preparing the backup receiver §

3.1. Storage qube configuration §

On the new laptop, create a standalone qube with the name of your choice (I'll refer to it as nfs), the following commands have been tested with the fedora-38-xfce template. Make sure to give it enough storage space for the backup.

First we need to configure the NFS server, we need to install the related package first:

$ sudo dnf install nfs-utils

After this, edit the file /etc/exports to export the path /home/user/backup to other computers, using the following content:

/home/user/backup *(rw,sync)

Create the directory we want to export, and make user the owner of it:

install -d -o user /home/user/backup

Now, run the NFS server now and at boot time:

systemctl enable --now nfs-server

You can verify the service started successfully by using the command systemctl status nfs-server

You can check the different components of the NFS server are running correctly, if the two following commands have an output this mean it's working:

  • ss -lapteun | grep 2049
  • ss -lapteun | grep 111

Allow the NFS server at the firewall level, run the following commands AND add them at the end of /rw/config/rc.local:

nft add rule qubes custom-input tcp dport 2049 accept
nft add rule qubes custom-input udp dport 111 accept

3.2. Route the service from the physical LAN §

Now the service is running within the qube, we need to allow the remote computer to reach it, by default the network should look like this:

We will make sys-net to nat the UDP port 111 and TCP port 2049 to sys-firewall, which will nat them to the nfs qube, which will already accept connections on those ports.

                         +------------------------------------------------+
  +--------+             |               DESTINATION SYSTEM               |
  | SOURCE |  ethernet   |  +---------+     +--------------+     +-----+  |
  | SYSTEM | <-------->  |  | sys-net | --> | sys-firewall | --> | nfs |  |
  +--------+             |  +---------+     +--------------+     +-----+  |
                         +------------------------------------------------+

3.2.1. sys-net routing §

Write the following script inside the sys-net qube of the destination system, make sure to update the value of the variable DESTINATION with sys-firewall's IP address, it can be found by looking at the qube settings.

#!/bin/sh

PORT=111
DESTINATION=10.138.31.246

if ! nft -nn list table ip qubes | grep "chain nat {" ; then
	nft add chain qubes nat { type nat hook prerouting priority dstnat\; }
fi

nft add rule qubes custom-input udp dport "${PORT}" accept
nft add rule qubes custom-forward udp dport "${PORT}" accept
nft add rule qubes nat iifname != "vif*" udp dport "${PORT}" dnat "${DESTINATION}"

PORT=2049
nft add rule qubes custom-input tcp dport "${PORT}" accept
nft add rule qubes custom-forward tcp dport "${PORT}" accept
nft add rule qubes nat iifname != "vif*" tcp dport "${PORT}" dnat "${DESTINATION}"

Make the script executable by running the command chmod +x on the script file. You will execute them later once the network is safe.

3.2.2. sys-firewall routing §

Write the following script inside the sys-firewall qube of the destination system, make sure to update the value of the variable DESTINATION with nfs's IP address, it can be found by looking at the qube settings.

#!/bin/sh

PORT=111
DESTINATION=10.137.0.10

if ! nft -nn list table ip qubes | grep "chain nat {" ; then
	nft add chain qubes nat { type nat hook prerouting priority dstnat\; }
fi

nft add rule qubes custom-input udp dport "${PORT}" accept
nft add rule qubes custom-forward udp dport "${PORT}" accept
nft add rule qubes nat iifname != "vif*" udp dport "${PORT}" dnat "${DESTINATION}"

PORT=2049
nft add rule qubes custom-input tcp dport "${PORT}" accept
nft add rule qubes custom-forward tcp dport "${PORT}" accept
nft add rule qubes nat iifname != "vif*" tcp dport "${PORT}" dnat "${DESTINATION}"

Make the script executable by running the command chmod +x on the script file. You will execute them later once the network is safe.

4. Backup process §

On the source system, we need to have a running qube that will mount the remote NFS server, this can be a disposable qube, an AppVM qube with temporary changes, a standalone etc...

4.1. Mounting qube §

On the mounting qube, run the following command to install the NFS tools we need:

dnf install nfs-utils

4.2. Configure both systems network §

In this step, you need to configure the network with the direct Ethernet cable, so the two systems can speak to each other, please disconnect from any Wi-Fi connections as you didn't set any security for the file transfer (it's encrypted but still).

You can choose any address as long as the two hosts are in the same subnet, an easy pick could be 192.168.0.2 for the source system, and 192.168.0.3 for the new system.

Now, both systems should be able to ping each other, it's time to execute the scripts in sys-firewall and sys-net to enable the routing.

On the "mounting" qube, run the following command as root to mount the remote file system:

mount.nvfs4 192.168.0.3:/home/user/backup /mnt

You can verify it worked if the output of df shows a line starting by 192.168.0.3:/home/user/backup, and you can ensure your user can actually write in this remote directory by running touch /mnt/test with the regular user user.

Now, we can start the backup tool to send the backup to the remote storage.

4.3. Run the backup §

In the source system dom0, run the Qubes OS backup tool, choose the qubes you want to transfer, uncheck "Compress backups" (except if you are tight on storage for the new system) and click on "Next".

In the field "Target qube", select the "mounting qube" and set the path to /mnt/, choose an encryption passphrase and run the backup.

If everything goes well, you should see a new file named qubes-backup-YYYY-MM-DDThhmmss in the directory /home/user/backups/ of the nfs qube.

4.4. Restore the backups §

In the destination system dom0, you can run the Restore backup tool to restore all the qubes, if the old sys-net and sys-firewall have any value, you may want to delete yours first otherwise the restored one will be renamed.

4.5. how to restore dom0 $home §

When you backup and restore dom0, only the directory /home/ is part of the backup, so it's only about the desktop settings themselves and not the Qubes OS system configuration. I actually use versioned files in the salt directories to have reproducible Qubes OS machines because the backups aren't enough.

Blog post: Using git bundle to synchronize a repository between Qubes OS dom0 and an AppVM

Blog post: Qubes OS dom0 files workflow using fossil

When you restore dom0, it creates a directory /home/solene/home-restore-YYYY-MM-DDThhmmss on the new dom0 that contains the previous /home/ directory.

Restoring this directory verbatim requires some clever trick as you should not be logged in for the operation!

  • reboot qubes OS
  • don't log in, instead press ctrl+alt+F2 to run commands as the root user in a console (tty)
  • move the backup outside /home/solene with mv /home/solene/home-restore* /home/
  • delete your home directory /home/solene with rm -fr /home/solene
  • put the old backup at the right place with mv /home/home-restore*/dom0-home/solene /home/
  • press ctrl+alt+F1
  • log-in as user

Your desktop environment should be like you left if during the backup. If you used some specific packages or desktop environment, make sure you also installed the according packages in the new dom0

5. Cleaning up §

After you restored your backups, you can remove the scripts in sys-firewall and sys-net and even delete the nfs qube.

6. Conclusion §

Moving my backup from the old system to the new one was pretty straightforward once the NFS server was established, I was able to quickly have a new working computer that looked identical to the previous one, ready to be used.

OpenBSD in a CI environment with sourcehut

Written by Solène, on 03 December 2023.
Tags: #openbsd #devops #git

Comments on Fediverse/Mastodon

1. Introduction §

If you ever required continuous integration pipelines to do some actions in an OpenBSD environment, you certainly figured that most Git "forge" didn't provide OpenBSD as a host environment for the CI.

It turns out that sourcehut is offering many environments, and OpenBSD is one among them, but you can also find Guix, NixOS, NetBSD, FreeBSD or even 9front!

Let's see how this works.

sourcehut official website

sourcehut: Documentation about host systems offering in CI

Note that the CI is only available to paid accounts, the minimal fee is "$2/month or $20/year". There are no tiers, so as long as you pay something you have a paid account. sourcehut is offering a clutter-free web interface, and developing an open source product that is also capable of running OpenBSD in a CI environment, I decided to support them (I really rarely subscribe to any kind of services).

PS: sourcehut supports Mercurial projects too.

2. The CI §

Upon each CI trigger, a new VM is created, it's possible to define the operating system and version you want for the environment, and then what to do in it.

The CI works when you have a "manifest" file in your project with the path .build.yml at the root of your project, it contains all the information about what to do.

sourcehut: Documentation about manifests and builds

3. Secret management §

When you run code in a CI, you often need secrets, and most often you require SSH keys if you want to push artefacts.

The SSH key secret is simplified, if sourcehut recognizes a secret to be a private SSH key, it will automatically save it at the right place.

sourcehut: Documentation about secrets in CI

4. Example §

Here is a simple example of a manifest file I use to build a website using the static generator hugo, and then push the result on a remote server.

image: openbsd/latest
packages:
  - hugo--
  - rsync--
secrets:
  - f20c67ec-64c2-46a2-a308-6ad929c5d2e7
sources:
  - git@git.sr.ht:~solene/my-project
tasks:
  - init: |
      cd my-project
      git clone https://github.com/adityatelange/hugo-PaperMod themes/PaperMod --depth=1
  - build: |
      cd my-project
      echo 'web.perso.pw ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKRj0NK7ZPMQgkgqw8V4JUcoT4GP6CIS2kjutB6xdR1P' | tee -a ~/.ssh/known_hosts
      make

On the example above, we can notice different parts:

  • image: this tells the manifest which OS to use, openbsd/latest means latest release.
  • packages: this tells which packages to install, it's OS-agnostic. I use extra dashes because some alternate versions of these packages exists, I just want the simple flavour for each.
  • secrets: this tells which secret I want among the secrets stored in sourcehut. This is a dedicated private SSH key in this case.
  • sources: this tells which sources to clone in the CI. Be careful though, if a repository is private, the CI needs to have the SSH key to access the repository. I spent some time figuring this the hard way.
  • tasks: this defines which commands to run, they are grouped in jobs.

If you use SSH, don't forget to either use ssh-keyscan to generate the content for ~/.ssh/known_hosts, or add the known fingerprint like me that would require an update if the SSH host key changes.

A cool thing is when your CI job failed, the environment will continue to live for at least 10 minutes while offering an SSH access for debug purpose.

sourcehut: Documentation about SSH into build environments

5. Conclusion §

I finally found a Git forge that is ethic and supportive of niche operating system. Its interface may be rude with fewer features, but it loads faster and is cleaner to understand. The price ($20/year) is higher than the competition (GitHub or GitLab) which can be used freely (up to some point) but they don't offer the CI choice and the elegant workflow sourcehut has.

6. Going further §

You can self-host a sourcehut instance if you prefer, it's open source and packaged for some Linux distributions.

sourcehut: Documentation about the deployment process

Run your own Syncthing relay server on OpenBSD

Written by Solène, on 03 November 2023.
Tags: #syncthing #openbsd #privacy #security #networking

Comments on Fediverse/Mastodon

1. Introduction §

In earlier blog posts, I covered the program Syncthing and its features, then how to self-host a discovery server. I'll finish the series with the syncthing relay server.

The Syncthing relay is the component that receives file from a peer to transmit it to the other when two peers can't establish a direct connection, by default Syncthing uses its huge worldwide community pool of relays. However, while data are encrypted, this leaks some information and some relays may be malicious and store files until it could be possible to make use of the content (weakness in encryption algorithm, better computers etc…).

Running your own Syncthing relay server will allow you to secure the whole synchronization between peers.

Syncthing official documentation: relay server

Related blog posts

Presenting Syncthing features

Blog post about the complementary discovery server

A simple use case for a relay: you have Syncthing configured between a smartphone on its WAN network and a computer behind a NAT, it's unlikely they will be able to communicate to each other directly, they will need a relay to synchronize.

2. Setup §

On OpenBSD, you will need the binary strelaysrv provided by the package syncthing.

# pkg_add syncthing

There is no rc file to start the relay as a service on OpenBSD 7.3, I added it to -current and will be available from OpenBSD 7.5, create an rc file /etc/rc.d/syncthing_relay with the following content:

#!/bin/ksh

daemon="/usr/local/bin/strelaysrv"
daemon_flags="-pools=''"
daemon_user="_syncthing"

. /etc/rc.d/rc.subr

rc_bg=YES
rc_reload=NO

rc_cmd $1

The special flag -pools='' is there to NOT join the community pool. If you want to contribute to the pool, remove this flag.

There is nothing else to configure, except enabling the service at boot, and running it, at the exception the need to retrieve an information from its runtime output:

rcctl enable syncthing_relay
rcctl -d start syncthing_relay

In the output, you will have a line looking like this:

2023/11/02 11:07:25 main.go:259: URI: relay://0.0.0.0:22067/?id=SCRGZW4-AAGJH36-M71EAPW-6XK7NXA-5CC1C4R-R2TKL2F-FNFF2OW-ZWA6WK5&networkTimeout=2m0s&pingInterval=1m0s&statusAddr=%3A22070

You need to note down the displayed URI, this is your relay address, just replace 0.0.0.0 by the actual server IP.

3. Firewall setup §

You need to open the port TCP/22067 for the relay to work, in addition, you can open the port 22070 which can be used to display a JSON with statistics.

To reach the status page, you need to visit the page http://$SERVER_IP:22070/status

4. Client configuration §

On the client Web GUI, click on "Actions" and "Settings" to open the settings panel.

In the "Connections tab", you need to enter the relay URI in the first field "Sync Protocol Listen Addresses", you can add it after default by separating the two values with a comma, that would add your own relay in addition to the community pool. You could entirely replace the value with the relay URI, in such situation, all peers must use the same relay, if they need a relay.

Don't forget to check the option "Enable relaying", otherwise the relay won't be used.

5. Conclusion §

Syncthing is greatly modular, it's pretty cool to be able to self-host all of its components separately. In addition, it's also easy to contribute to the community pool if one decides to.

My relay is set up within a VPN where all my networks are connected, so my data are never leaving the VPN.

6. Going further §

It's possible to use a shared passphrase to authenticate with the remote relay, this can be useful in the situation where the relay is on a public IP, but you only want the nodes holding the shared secret to be able to use it.

Syncthing relay server documentation: Access control for private relays

Read quoted-printable emails with qprint

Written by Solène, on 27 October 2023.
Tags: #openbsd #linux #unix

Comments on Fediverse/Mastodon

1. Introduction §

You may already have encountered emails in raw text that contained weird characters sequences like =E3 or =09, especially if you work with patch files embedded as text in emails.

There is nothing wrong with the text itself, or the sender email client. In fact, this shows the email client is doing the right thing by applying the RFC 1521. Non-ASCII character should be escaped in some way in emails.

RFC 1521: MIME part one

This is where qprint enters in action, it can be used to encode using the quoted-printable, or decode such content. The software can be installed on OpenBSD with the package named qprint.

qprint official website

I already introduced qprint in a blog post in a guide about OpenBSD pledge.

2. What does quoted-printable look like? §

If you search for an email from the OpenBSD mailing list, and display it in raw format, you may encounter this encoding. There isn't much you can do with the file, it's hard to read and can't be used with the program patch.

Email example featuring quoted-printable characters

A sample of the email looks like that:

	From italiano-=E6=97=A5=E6=9C=AC=E8=AA=9E (=E3=81=AB=E3=81=BB=E3=82=93=
=E3=81=94) FreeDict+WikDict dictionary ver.
	2022.11.18 [itajpn]:
=09
	  ciao //'=CA=A7ao// <interjection>
	  =E3=81=93=E3=82=93=E3=81=AB=E3=81=A1=E3=81=AF
=09

If you pipe this content through the command qprint -d, you will obtain a much more interesting text:

	From italiano-日本語 (にほんご) FreeDict+WikDict dictionary ver.
	2022.11.18 [itajpn]:
	
	  ciao //'ʧao// <interjection>
	  こんにちは
	

There is little use in encoding content with qprint, but it could do it as well.

3. Conclusion §

If you ever encounter this kind of encoding, now you should be able to figure what it is, and how to read it.

Qprint may not be available on all systems, but compiling it is quite easy, as long as you have a C compiler and make installed.

Run your own Syncthing discovery server on OpenBSD

Written by Solène, on 18 October 2023.
Tags: #syncthing #openbsd #privacy #security #networking

Comments on Fediverse/Mastodon

1. Introduction §

In a previous article, I covered the software Syncthing and mentioned a specific feature named "discovery server".

The discovery server is used to allow clients to connect each other through NATs to help connect each other, this is NOT a relay server (which is a different service) that serves as a proxy between clients.

A motivation to run your own discovery server(s) would be for security, privacy or performance reasons.

  • security: using global servers with the software synchronizing your data can be dangerous if a remote exploit is found in the protocol, running your own server will reduce the risks
  • privacy: the global servers know a lot about your client if you sync online: time of activity, IP address, number of remote nodes, the ID of everyone involved etc...
  • my specific use case where I have two Qubes OS computer with multiple syncthing inside, they can't see each other as they are in separate networks, and I don't want the data to go through my slow ADSL to sync locally...

Let's see how to install your own Syncthing discovery daemon on OpenBSD.

Syncthing discovery daemon documentation

Related blog posts

Presenting Syncthing features

Blog post about the complementary Relay server

2. Setup §

On OpenBSD, the binary we need is provided by syncthing package.

# pkg_add syncthing

The relay service is done by the binary stdiscosrv, you need to create a service file to enable it at boot. We can use the syncthing service file as a template for the new one. In OpenBSD-current and from OpenBSD 7.5 the rc file will be installed with the package.

# sed '/^daemon=/ s/syncthing/stdiscosrv/ ; /flags/ s/".*"/""/' /etc/rc.d/syncthing > /etc/rc.d/syncthing_discovery
# chmod a+x /etc/rc.d/syncthing_discovery

You created a service named syncthing_discovery, it's time to enable and start it.

# rcctl enable syncthing_discovery

You need to retrieve the line "Server device IS is XXXX-XXXX......" from the output, keep the ID (which is the XXXX-XXXX-XXXX-XXXX part) because we will need to reuse it later. We will start the service in debug mode to display the binary output in the terminal.

# rcctl -d start syncthing_discovery

Make sure your firewall is correctly configured to let pass incoming connections on port TCP/8443 used by the discovery daemon.

3. Client configuration §

On the client Web GUI, click on "Actions" and "Settings" to open the settings panel.

In the "Connections tab", you need to change the value of "Global Discovery servers" from "Default" to https://IP:8443/?id=ID where IP is the IP address where the discovery daemon is running, and ID is the value retrieved at the previous step when running the daemon.

Depending on your use case, you may want to have the global discovery server plus yours, it's possible to use multiple servers, in which case you would use the value default,https://IP:8443/?id=ID.

4. Conclusion §

If you change the default discovery server by your own, make sure all the peers can reach it, otherwise your syncthing clients may not be able to connect to each other.

5. Going further §

By default, the discovery daemon will generate self-signed certificate, you could use a Let's Encrypt certificate if you prefer.

There are some other options like prometheus export for getting metrics or changing the connection port, you will find all the extra options in the documentation / man page.

Port of the Week: Presenting Syncthing

Written by Solène, on 04 October 2023.
Tags: #syncthing #privacy #security #networking

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1. Introduction §

Today's "port of the week" article is featuring Syncthing, a file synchronization software.

Syncthing official project website

Related blog posts:

Blog post about the complementary Relay server

Blog post about the complementary discovery server

2. Quick intro §

As stated earlier, Syncthing is a network daemon that synchronize files between computers/phones. Each Syncthing instance must know the other instance ID to trust them and find them over the network. The transfer are encrypted and efficient, the storage itself can be encrypted.

Some Syncthing vocabulary:

  • a folder: a local directory that is shared with a remote device,
  • a remote device: a remote computer running Syncthing, each of them have a unique ID and a user-defined name, you can choose which shared folders you want to synchronize with them
  • an item: this word appears when syncing two remotes, an item can be either a directory or a file that isn't synchronized yet
  • a discovery server: a server which helps remotes finding known remotes over the Internet, or in the worst case scenario, relays data from a remote to another if they can't communicate directly

3. Interesting features §

I gathered a list of interesting features that you may find interesting in Syncthing.

3.1. Security: authentication and encryption §

When you need to add a new remote, you need to add the remote's ID on a Syncthing and trust that one on the remote one. The ID is a human representation of the Syncthing instance certificate fingerprint. When you exchange ID, you are basically asked to review each certificate and allow each instance to trust the other.

All network transfers occurring between two Syncthing are encrypted using TLS, as the remote certificate can be checked, the incoming data integrity can be verified and authenticated.

Syncthing official documentation about security principles in the software

3.2. Relaying §

I guess this is Syncthing killer feature. Connecting two remotes is very easy and file transfer between them can bypass firewalls and NATs.

This works because the Syncthing offers a default discovery server which has two purposes:

  • if the two servers could potentially communicate to each other but are behind NATs, it does what we call "hole punching" to establish a connection between the two remotes and allow them to transfer directly from one to the other
  • if the two servers can't communicate to each other, the discovery server acts as a relay for the data

The file transfer is still encrypted, but having a third party server involved may rise privacy issues, and security risks if a vulnerability can be exploited.

My next blog post will show how to self-host your own Syncthing relay, for better privacy and even more complicated setups!

Note that the discovery server or the relaying can be disabled! You could also build a mesh VPN and run Syncthing on each node without using any relay or discovery server.

3.3. Built-in file versioning §

This may be my preferred feature in Syncthing!

On a given Syncthing instance, you can enable per shared folder a retention policy, aka file versioning in the interface.

Basically, if a file is modified / removed in the share by a remote, the local instance can keep a hidden copy for a while.

There are different versioning modes, from a simple "trash bin" style keeping the files for n days, or more elaborated policies like you could have in backup tools.

Syncthing official documentation about file versioning

3.4. Partial share synchronization §

For each share, it's possible to write an exclusion filter, this allows you to either discard sync changes for some pattern (like excluding vim swap files) or entire directories if you don't want to retrieve all the shared folder.

The filter works in both way, if you accept a remote, you could write a filter before starting the synchronization and remove some huge directories you may not want locally. But this could also allow preventing a directory to be sent to the remotes, like a temporary directory for instance.

This is a topic I covered with a very specific use case, only sync a single file in a directory.

Earlier blog post: Configure Syncthing to sync a single file

3.5. Encrypted remotes §

A pretty cool feature I found recently was the support for encrypted shared folders per remote. I'm using syncthing to keep my KeepassXC databases synchronized between my computers.

As I don't always have at least two of my computers turned ON at the same time, they can't always synchronize directly with each other, so I use a remote dedicated server as a buffer to hold the files, Syncthing encryption is activated for this remote, both my computers can exchange data with it, but on the server itself you can't get my KeepassXC databases.

This is also pretty cool as it doesn't leave any readable data on the storage drive if you use 3rd party systems.

Taking the opportunity here, KeepassXC has a cool feature that allows you to add a binary file as a key in addition to a password / FIDO key. If this binary file isn't part of the synchronized directory, even someone who could access your KeepassXC database and steal your password shouldn't be able to use it.

3.6. Data chunk based §

When Syncthing scans a directory, it will hash all the file into chunks and synchronize all these chunks to other remotes, this is basically how BitTorrent work too.

This may sound boring, but basically, this allows Syncthing to move or rename files on a remote instead of transferring the data again when you rename / move files in a local shared directory. Indeed, only the changed paths list is sent, and the chunks used in the files, as the files already exist on the remote, the data chunks don't have to be retrieved.

Note that this doesn't work for encrypted remotes as the chunks contain some path information, once encrypted, the same file with different paths will look as two different encrypted chunks.

3.7. Bandwidth control §

Syncthing GUI allows you to define inbound or outbound bandwidth limitation, either globally or per remote. If like me, you have a slow ADSL line with slow upload, you may want to limit the bandwidth used to send data to set the non-local remotes.

3.8. Support for all attributes synchronization §

This may sound more niche, but it's important for some users: Syncthing can synchronize file permissions, ownership or even extended attributes. This is not enabled by default as Syncthing requires elevated privileges (typically running as root) to make it work.

3.9. Runs everywhere §

Syncthing is a Go program, it's a small binary with no dependencies, it's quite portable and runs on Linux, all the BSD, Android, Windows, macOS etc... There is nothing worse than a synchronization utility that can't be installed on a specific computer...

4. Conclusion §

I really love this software, especially since I figured the file versioning and the encrypted remotes, now I don't fear conflicts or lost files anymore when syncing my files between computers.

My computers also use a local discovery server that allows my Qubes OS to be kept in sync together over the LAN.

5. Note for SystemD users §

When you install Syncthing on your system, you can enable the service as your user, this will make Syncthing start properly when you log in with your user:

systemctl enable --user syncthing.service

6. Note for OpenBSD users §

Syncthing has to listen for each file change, you will need to increase the maximum opened files limit for your user, and maybe the limit in the kernel using the according sysctl.

You can find more detailed information about using Syncthing on OpenBSD in the file /usr/local/share/doc/pkg-readmes/syncthing.

Introduction to the OpenBSD operating system

Written by Solène, on 01 October 2023.
Tags: #openbsd #bsd #octopenbsd

Comments on Fediverse/Mastodon

1. Introduction §

I often see a lot of confusion with regard to OpenBSD, either assimilate as a Linux distribution or mixed up with FreeBSD.

Let's be clear, OpenBSD is a stand alone operating system. It came as a fork of NetBSD in 1994, there isn't much things in common between the two nowadays.

While OpenBSD and the other BSDs are independant projects, they share some very old roots in their core, and regularly see source code changes in one being imported to another, but this is really a very small amount of the daily code changes though.

2. OpenBSD features in 60 seconds §

Let's do it quick, what can you find in OpenBSD?

  • a complete operating system with X, network services, compilers, all out of the box
  • 100% community driven
  • more than 11000 packages with stuff like GNOME, Xfce, LibreOffice, Chromium, Firefox, KDE applications, GHC etc... (and KDE Plasma SOON!)
  • a release every 6 months
  • sandboxed web browsers
  • stack smash memory protection
  • where OpenSSH is developped
  • accurate manual pages for everything

It's used with success on workstations, either for personal or professional use. It's also widely used as a server, being for network services or just routing/filtering network!

All the innovations that happened in OpenBSD

3. Give it a try? §

3.1. On a Live-CD §

If you never used OpenBSD, you can easily give it a try using the community made LiveCD/LiveUSB FuguIta!

FuguIta project page

Older blog page about FuguIta

3.2. In a virtual machine §

Another way to easily try OpenBSD is to run it in a virtual machine.

Complete installation guide of OpenBSD

Please note that the VirtualBox additions are not available as their drivers never got written for OpenBSD.

3.3. On a real system §

You can install OpenBSD on your system, or a spare computers you don't use anymore. You need at least 48 MB of memory for it to work, and many architectures are supported like arm64, amd64, i386, sparc64, powerpc, riscv...

Complete installation guide of OpenBSD

3.4. On a VPS §

You can rent an OpenBSD VM on OpenBSD Amsterdam, a company doing OpenBSD hosting on OpenBSD servers using the OpenBSD hypervisor! And they give money to the OpenBSD project for each VM they host!

OpenBSD Amsterdam hosting

4. Installing GNOME §

I made a tutorial showing how to install GNOME, it's fairly easy!

How to install GNOME on OpenBSD (video tutorial)

5. We play video games on OpenBSD! §

This is actually possible, and always running native code to run video games.

OpenBSD Gaming video channel (peertube)

PlayOnBSD Games compatibility list

OpenBSD_gaming subreddit community

6. Going further §

The OpenBSD project website

OpenBSD on Wikipedia

This is OctOpenBSD month

Written by Solène, on 01 October 2023.
Tags: #openbsd #unix #bsd #octopenbsd

Comments on Fediverse/Mastodon

1. Introduction §

We are in October 2023, let's celebrate the first OctOpenBSD event, the month where OpenBSD users show to the world our favorite operating system is still relevant.

The event will occur from 1st October up to 31st October. A surprise will be revealed on the OpenBSD Webzine for the last day!

The OpenBSD Webzine website

A Puffy telling the hacker girl that sometimes we need to take a break
A Puffy telling the hacker girl that sometimes we need to take a break

Artwork by Prahou, the unix_surrealism artist

2. What to do in OctOpenBSD? §

There is a lot you can do! It's just small things, that accumulated as a community will turn this into a great community event!

To contribute to OctOpenBSD, you can:

  • Write content about OpenBSD (why/when you started using it, tutorials, why you like it)
  • Make artworks!
  • Ask questions about OpenBSD if you need to know something
  • Share screenshots of your system on your favorite social network
  • Take pictures of your computers when feature OpenBSD

Let's celebrate!

3. FAQ §

If you have any question about the event, I'll answer them and gather the QA in this section.

Firefox hardening with Arkenfox

Written by Solène, on 24 September 2023.
Tags: #firefox #security #privacy

Comments on Fediverse/Mastodon

1. Introduction §

Dear Firefox users, what if I told you it's possible to harden Firefox by changing a lot of settings? Something really boring to explain and hard to reproduce on every computer. Fortunately, someone did the job of automating all of that under the name Arkenfox.

Arkenfox design is simple, it's a Firefox configuration file (more precisely a user.js file), that you have to drop in your profile directory to override many Firefox defaults with a lot of curated settings to harden privacy and security. Cherry on cake, it features an updater and a way to override some of its values with a user defined file.

This makes Arkenfox easy to use on any system (including Windows), but also easy to tweak or distribute across multiple computers.

Arkenfox user.js GitHub project page

Arkenfox user.js Documentation

2. Setup §

The official documentation contains more information, but basically the steps are the following:

  1. find your Firefox profile directory: open about:support and search for an entry name profile directory
  2. download latest Arkenfox user.js release archive
  3. if the profile is not new, there is an extra step to clean it using scratchpad-scripts/arkenfox-cleanup.js which contains instructions at the top of the file
  4. save the file user.js in the profile directory
  5. add update.sh to the profile directory, so you can update user.js easily later
  6. create user-overrides.js in the profile directory if you want to override some settings and keep them, the updater is required for the override

3. Configuration §

Basically, Arkenfox disables a lot of persistency such as cache storage, cookies, history. But it also enforces a canvas of fixed size to render the content, reset the preferred languages to English only (that defines which language is used to display a multilingual website) and many more changes.

You may want to override some settings because you don't like them. In the project's Wiki, you can find all Arkenfox overrides, with the explanation of its new value, and which value you may want to use in your own override.

Arkenfox user.js Wiki about common overrides

For instance, if you want to re-enable the cache storage, add the following code to the file user-overrides.js.

user_pref("browser.cache.disk.enable", true);
user_pref("privacy.clearOnShutdown.cache", false);

Now, run the updater script, that will verify that Arkenfox user.js file is the latest version, and will append your override to it.

4. Tips §

By default, cookies aren't saved, so if you don't want to log in every time you restart Firefox, you have to specifically allow cookies for each website.

The easiest method I found is to press Ctrl+I, visit the Permissions tab, and uncheck the "Default permissions" relative to cookies. You could also do it by visiting Firefox settings, and search for an exception button in which you can enter a list of domains where cookies shouldn't be cleared on shutdown.

By default, entering text in the address bar won't trigger a search anymore, so instead of using Ctrl+L to type in the bar, you can use Ctrl+K to type for a search.

5. Extensions §

Arkenfox wiki recommends to use uBlock Origin and Skip redirect extensions only, with some details. I agree they both work well and do the job.

It's possible to harden uBlock Origin by disabling 3rd party scripts / frames by default, and giving you the opportunity to allow per domain / globally some sources, this is called the blocking mode. I found it to be way more usable than NoScript.js.

uBlock Origin blocking mode documentation

6. Conclusion §

I found that Arkenfox was a bit hard to use at first because I didn't fully understand the scope of its changes, but it didn't break any website even if it disables a lot of Firefox features that aren't really needed.

This reduces Firefox attack surface, and it's always a welcome improvement.

7. Going further §

Arkenfox user.js isn't the only set of Firefox settings around, there is also Betterfox (thanks prx!) which provides different profiles, even one for performance. I didn't try any of these profiles yet, Arkenfox and Betterfox are parallel projects and not forks, it's actually complicated to compare which one would be better.

Betterfox Github project page

Flatpak integration in Qubes OS templates

Written by Solène, on 15 September 2023.
Tags: #flatpak #qubesos #linux

Comments on Fediverse/Mastodon

1. Introduction §

I recently wanted to improve Qubes OS accessibility to new users a bit, yesterday I found why GNOME Software wasn't working in the offline templates.

Today, I'll explain how to install programs from Flatpak in a template to provide to other qubes. I really like flatpak as it provides extra security features and a lot of software choice, and all the data created by Flatpak packaged software are compartmentalized into their own tree in ~/.var/app/program.some.fqdn/.

Qubes OS official project website

Flatpak official project website

Flathub: main flatpak repository

2. Setup §

All the commands in this guide are meant to be run in a Fedora or Debian template as root.

In order to add Flathub repository, you need to define the variable https_proxy so flatpak can figure how to reach the repository through the proxy:

export all_proxy=http://127.0.0.1:8082/
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

Make the environment variable persistent for the user user, this will allow GNOME Software to work with flatpak and all flatpak commands line to automatically pick the proxy.

mkdir -p /home/user/.config/environment.d/
cat <<EOF >/home/user/.config/environment.d/proxy.conf
https_proxy=http://127.0.0.1:8082/
EOF

In order to circumvent a GNOME Software bug, if you want to use it to install packages (Flatpak or not), you need to add the following line to /rw/config/rc.local:

ip route add default via 127.0.0.2

GNOME Software gitlab issue #2336 saying a default route is required to make it work

Restart the template, GNOME software is now able to install flatpak programs!

3. Qubes OS integration §

If you install or remove flatpak programs, either from the command line or with the Software application, you certainly want them to be easily available to add in the qubes menus.

Here is a script to automatically keep the applications list in sync every time a change is made to the flatpak applications.

If you don't want to use the automated script, you will need to run /etc/qubes/post-install.d/10-qubes-core-agent-appmenus.sh, or click on "Sync applications" in the template qube settings after each flatpak program installation / deinstallation.

3.1. Inotify-tool (optional) §

For the setup to work, you will have to install the package inotify-tools in the template, this will be used to monitor changes in a flatpak directory.

3.2. Syncing app menu script §

Create /usr/local/sbin/sync-app.sh:

#!/bin/sh

# when a desktop file is created/removed
# - links flatpak .desktop in /usr/share/applications
# - remove outdated entries of programs that were removed
# - sync the menu with dom0

inotifywait -m -r \
-e create,delete,close_write \
/var/lib/flatpak/exports/share/applications/ |
while  IFS=':' read event
do
    find /var/lib/flatpak/exports/share/applications/ -type l -name "*.desktop" | while read line
    do
        ln -s "$line" /usr/share/applications/
    done
    find /usr/share/applications/ -xtype l -delete
    /etc/qubes/post-install.d/10-qubes-core-agent-appmenus.sh
done

You have to mark this file as executable with chmod +x /usr/local/sbin/sync-app.sh.

3.2.1. Start the file monitoring script at boot §

Finally, you need to activate the script created above when the templates boots, this can be done by adding this snippet to /rw/config/rc.local:

# start monitoring flatpak changes to reload icons
/usr/local/sbin/sync-app.sh &

3.3. Updating §

You can automatically run flatpak upgrade after a template update. After a dnf change, all the scripts in /etc/qubes/post-install.d/ are executed.

Create /etc/qubes/post-install.d/05-flatpak-update.sh with the following content, and make the script executable:

#!/bin/sh
export all_proxy=http://127.0.0.1:8082/
flatpak upgrade -y --noninteractive

Every time you update your template, flatpak will upgrade after and the application menus will also be updated if required.

4. Conclusion §

With this setup, you can finally install programs from flatpak in a template to provide it to other qubes, with bells and whistles to not have to worry about creating desktop files or keeping them up to date.

Please note that while well-made Flatpak programs like Firefox will add extra security, the repository flathub allows anyone to publish programs. You can browse flathub to see who is publishing which software, they may be the official project team (like Mozilla for Firefox) or some random people.

How to add pledge to a program in OpenBSD

Written by Solène, on 08 September 2023.
Tags: #security #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

This article is meant to be a simple guide explaining how to make use of the OpenBSD specific feature pledge in order to restrict a software capabilities for more security.

While pledge falls in the sandboxing features, it's different than the traditional sandboxing we are used to see because it happens within the source code itself, and can be really tightened. Actually, many programs requires lot of privileges like reading files, doing DNS etc... when initializing, then those privileges could be removed, this is possible with pledge but not for traditional sandboxing wrappers.

In OpenBSD, most of the base userland have support for pledge, and more and more packaged software (including Chromium and Firefox) received some code to add pledge. If a program tries to use a system call that isn't in pledge promises list, it dies and the violation is reported in the system logs.

What makes pledge pretty cool is how it's easy to implement it in your software, it has a simple mechanism of system call families so you don't have to worry about listing every system calls, but only their categories (named promises), like reading a file, writing a file, executing binaries etc...

OpenBSD manual page for pledge(2)

2. Let's pledge a program §

I found a small utility that I will use to illustrate how to add pledge to a program. The program is qprint, a C quoted printable encoder/decoder. This kind of converter is quite easy to pledge because most of the time, they only take an input, do some computation and make an output, they don't run forever and don't do network.

qprint official project page

2.1. Digging in the sources §

When extracting the sources, we can find a bunch of files, we will focus at reading the *.c files, the first thing we want to find is the function main().

It happens the main function is in the file qprint.c. It's important to call pledge as soon as possible in the program, most of the time after variable initialization.

2.2. Modifying the code §

Adding pledge to a program requires to understand how it works, because some feature that aren't often used may be broken by pledge, and some programs having live reloading or being able to change behavior during runtime are complicated to pledge.

Within the function main below variables declaration, We will add a call to pledge for stdio because the program can display the result on the output, rpath because it can read files and wpath as it can also write files.

#include <unistd.h>
[...]

pledge("stdio rpath wpath", NULL);

It's ok, we imported the library providing pledge, and called it from within. But what if the pledge call fails for some reasons? We need to ensure it worked or abort the program. Let's add some checks.

#include <unistd.h>
#include <err.h>

[...]

if (pledge("stdio rpath wpath", NULL) == -1) {
    err(1, "pledge call didn't work");
}

This is a lot better now, if pledge call failed, the program will stop and we will be warned about it. I don't know exactly under which circumstance it could fail, but maybe if promise name changes or doesn't exist anymore in a program, that would be bad if pledge silently failed.

2.3. Testing §

Now we made some changes to the program, we need to verify it's still working as expected.

Fortunately, qprint comes with a test suite which can be used with make wringer, if the test suite pass and the tests have a good coverage, this mean we may have not break anything. If the test suite fails, we should have an error in the output of dmesg telling us why it failed.

And, it failed!

qprint[98802]: pledge "cpath", syscall 5

This error (which killed the PID instantly) indicates that the pledge list is missing cpath, this makes sense because it has to create new files if you specify an output file.

Adding cpath to the list, and running the test suite again, all tests pass! Now, we exactly know that the software can't do anything except using the system calls we whitelisted.

We could tighten pledge more by dropping rpath if the file is read from stdin, and cpath wpath if the output is sent to stdout. I left this exercise to the reader :-)

2.4. The diff §

Here is my diff to add pledge support to qprint.

Index: qprint.c
--- qprint.c.orig
+++ qprint.c
@@ -2,6 +2,8 @@
 #line 70 "./qprint.w"
 
 #include "config.h"                   
+#include <unistd.h>
+#include <err.h>
 
 #define REVDATE "16th December 2014" \
 
@@ -747,6 +749,9 @@ char*cp;
 
 
 
+if (pledge("stdio cpath rpath wpath", NULL) == -1) {
+  err(1, "pledge error");
+}
 
 fi= stdin;
 fo= stdout;

3. Using pledge in non-C programs §

It's actually possible to call pledge() in other programming languages, Perl has a library provided in OpenBSD base system that will work out of the box. For some other, such library may be packaged already (for python and Golang at least). If you use something less common, you can define an interface to call the library.

OpenBSD manual page for the Perl pledge library

Here is an example in Common LISP to create a new function c-kiosk-pledge.

#+ecl
(progn
  (ffi:clines "
    #include <unistd.h>

    void kioskPledge() {
       pledge(\"dns inet stdio tty rpath\",NULL);
    }
    #endif")

  #+openbsd
  (ffi:def-function
     ("kioskPledge" c-kiosk-pledge)
     () :returning :void))

4. Extra §

It's possible to find which running programs are currently using pledge() by using ps auxww | awk '$8 ~ "p" { print }', any PID with a state containing p indicates it's pledged.

If you want to add pledge to a packaged program on OpenBSD, make sure it still fully work.

Adding pledge to a program that contain most promises won't be doing much...

5. Exercise reader §

Now, if you want to practice, you can tighten the pledge calls to only allow qprint to use the pledge stdio only in the case it's used in a pipe for input and output like this: ./qprint < input.txt > output.txt.

Ideally, it should add the pledge cpath wpath only when it writes into a file, and rpath only when it has to read a file, so in the case of using stdin and stdout, only stdio would have been added at the beginning.

Good luck, Have fun! Thanks to Brynet@ for the suggestion!

6. Conclusion §

The system call pledge() is a wonderful security feature that is reliable, and as it must be done in the source code, the program isn't run from within a sandboxed environment that may be possible to escape. I can't say pledge can't be escaped, but I think it's a lot less likely to be escaped than any other sandbox mechanism (especially since the program immediately dies if it tries to escape).

Next time, I'll present its companion system called unveil which is used to restrict access to the filesystem, except some developer defined files.

My top 20 video games

Written by Solène, on 31 August 2023.
Tags: #life #gaming

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to share my favorite games list of all time. Making the list wasn't easy though, but I've set some rules to help deciding myself.

Here are the criteria:

  • if you show me the game, I'd be happy to play it again
  • if it's a multiplayer game, let's assume we could still play it
  • the nostalgia factor should be discarded
  • let's try to avoid selecting multiple similar games
  • I'd love being able to forget the story to play it again from a fresh point of view

Trivia, I'm not a huge gamer, I still play many games nowaday, but I only play each of them for a couple of hours to see what they have to offer in term of gameplay, mechanics, and see if they are innovative in some way. If a game is able to surprise me or give me something new, I may spend a bit more time on it.

2. My top 20 §

Here is the list of my top 20 games I enjoyed, and with which I'd be fine to enjoy play them again anytime.

I tried to elect some games to be a bit better than the other, so there is my top 3, top 10, and the top 20. I haven't been able to rank them from 1 to 20, so I just made tiers.

2.1. Top 20 to 11 §

2.1.1. Heroes of Might and Magic III §

Product page on GOG

I spent so many hours playing with my brother or friends, sharing the mouse each turn so everyone could play with a single computer.

And not only the social factor was nice, the game was cool, there are many different factions to play, the game is cool and there is strategy at play to win. A must have.

2.1.2. Saturn Bomberman §

Game review

The Sega Saturn hasn't been very popular, but it had some good games, and one is Saturn Bomberman. From all the games from the Bomberman franchise, this looks really the best, it featured some dinosaurs with unique abilities, and they could grow up, some weird items, many maps.

And it had an excellent campaign that was long to play, and could be played in coop! The campaign was really really top notch for this kind of game, with unique items you couldn't find in multiplayer.

2.1.3. Tony Hawk's Pro Skater 1 and 2 §

Product page on Epic Game Store

I guess this is a classic, I played a lot the Nintendo 64 version, and now we have the 1+2 games into one, with high refresh rate, HD textures and still the same good music.

A chill game that is always fun to play.

2.1.4. Risk of rain 2 §

Product page on Steam

A pure rogue-like that shines in multiplayer, lot of classes, lot of weapons, lot of items, lot of enemies, lot of fun.

While it's not the kind of game I'd play all day, I'm always up for a run or two.

2.1.5. Warhammer 40K: Dawn of War §

Product page on Steam (Dark Crusade)

This may sound like heresy, but I never played the campaign of this game. I just played skirmish or in multiplayer with friends, and with the huge factions choice with different gameplay, it's always cool even if the graphics aged a bit.

Being able to send dreadnought from space directly into the ork base, or send legions of necrons to that Tau player is always source of joy.

2.1.6. Street Fighter 2 Special Champion Edition §

Video review on YouTube

A classic on the megadrive/genesis, it's smooth, music is good. So many characters and stages, incredible soundtracks. The combos were easy to remember, just enough to give each character their own identity and allow players to quickly onboard.

Maybe the super NES version is superior, but I always played it on megadrive.

2.1.7. Slay the Spire §

Product page on GOG

Maybe the game which demonstrated we can do great deck based video games.

Playing a character with a set of skills as cards, gathering items while climbing a tower, it can get a bit repetitive over time though, but the game itself is good and doing a run occasionally is always tempting.

The community made a lot of mods, even adding new characters with very specific mechanics, I highly recommend it for anyone looking for a card based game.

2.1.8. Monster Hunter 4 Ultimate §

Game review on IGN

My first Monster Hunter game, on 3DS. I absolutely loved it, insane fights against beloved monsters (we need to study them carefully, so we need to hunt a lot of them :P).

While Monster Hunter World shown better graphics and smoother gameplay, I still prefer the more rigid MH like MH4U or MH Generations Ultimate.

The 3D effect on the console was working quite well too!

2.1.9. Peggle Nights §

Product page on Steam

A simple arcade game with some extra powers depending on the character you picked. It's really addictive despite the gameplay being simplistic.

2.1.10. Monster Train §

Product page on GOG

A very good card game with multiple factions, but not like Slay the Spire.

There are lot of combos to create as cards are persistent within the train, and runs are not that much depending on RNG (random number generator), which make it a great game.

2.2. Top 10 to 4 §

Not ranked, let's enter the top 10 up to just before the top 3.

2.2.1. Call of Cthulhu: Prisoner of Ice §

Product page on GOG

One of the first PC game I played, when I was 6. I'm not into point & click usually, but this one features Lovecraft horrors, so it's good :)

2.2.2. The Elder Scrolls IV: Oblivion §

Product page on GOG

A classic among the RPG, I wanted to put an Elder Scrolls game into the list and I went with Oblivion. In my opinion, this was the coolest one compared to Morrowind or Skyrim. I have to say, I just hesitated with Morrowind, but because of all Morrowind flaws and issues, Oblivion built a better game. Skyrim was just bad for me, really boring and not interesting.

Oblivion gave the opportunity to discover many cities with day/night cycle, NPC that had homes and were at work during day, the game was incredible when it was released, and I think it's still really good.

Trivia, I never did the story of Morrowind or Oblivion, but yet I spent a lot of time playing them!

2.2.3. Shining the Holy Ark §

Video review on YouTube

Another Sega Saturn game, almost unknown to the public I guess. While not a Shining Force game, it's part of the franchise.

It's an RPG / dungeon crawler in first person view, in which you move from tiles to tiles and sometimes fight monster with your team.

2.2.4. Into the Breach §

Product page on GOG

The greatest puzzle game I ever played. It's like chess, but actually fun. Moving some mechas on a small tiled board when it's your turn, you must think about everything that will happen and in which order.

The number of mechas and equipment you find in the game make it really replayable, and game sessions can be short so it's always tempting to start yet another run.

2.2.5. Like a Dragon §

Product page on GOG

My first Yakuza / Like a dragon game, I didn't really know what to expect, and I was happy to discover it!

A Japanese RPG / turn based game featuring the most stupid skills or quests I've ever seen. The story was really engaging, unlocking new jobs / characters leads to more stupidity around.

2.2.6. Secret of Mana §

Game review on IGN

A super NES classic, and it was possible to play in coop with a friend!

The game had so much content, lot of weapons, of magic, of monsters, the soundtrack is just incredible all along. And even more, at some point in the game you have the opportunity to move from your current location by riding a dragon in a 3D view over the planet!

I start and finish this game every few years!

2.2.7. Baldur's Gate 3 §

Product page on GOG

At the moment, it's the best RPG I played, and it's turn based like how I like them.

I'd have added Neverwinter Night, but BG3 does better than it in every way, so I retained BG3 instead.

Every new game could be played a lot differently than the previous one, there are so many possibilities out there, it's quite the next level of RPG compared to what we had before.

2.3. Top 3 §

And finally, not ranked but my top 3 of my favorite games!

2.3.1. Factorio §

Product page on GOG

After hesitating between Factorio and Dyson Sphere Program in the list, I chose to retain Factorio, because DSP is really good, but I can't see myself starting it again and again like Factorio. DSP has a very very slow beginning, while Factorio provides fun much faster.

Factorio invented a new genre of game: automation. I get crazy with automation, optimization. It's like doing computer stuff in a game, everything is clean, can be calculated, I could stare at conveyor belts transporting stuff like I could stare at Gentoo compilation logs for hours. The game is so deep, you can do crazy things, even more when you get into the logic circuits.

While I finished the game, I'm always up for a new world with some goals, and modding community added a lot of high quality content.

The only issue with this game is that it's hard to stop playing.

2.3.2. Street of rage 4 §

Product page on GOG

While I played Street of Rage 2 a lot more than the 4Th, I think this modern version is just better.

You can play with a friend almost immediately, fun is there, brawling bad guys is pretty cool. The music are good, the character roster is complete, it's just 100% fun to play it again and again.

2.3.3. Outer Wilds §

Product page on Steam

That's one game I wish I could forget to play it again...

It gave me a truly unique experience as a gamer.

It's an adventure game featuring a time loop of 15 minutes, the only things you acquire in the game is knowledge in your own mind. With that knowledge, you can complete the game in different ways, but first, you need to find clues leading to other clues, leading to some pieces of the whole puzzle.

3. Games that I couldn't put in the list §

There are some games I really enjoyed, but for some reasons I haven't been able to put them in the list, could be replayability issues or the nostalgia factor that was too high maybe?

  • Rimworld
  • Left 4 Dead
  • any Mario Kart game
  • Warcraft III: Frozen Throne
  • Death Stranding
  • Tetris
  • The Story of Thor
  • Neverwinter Nights
  • Morrowind
  • Dyson Sphere Program
  • Diablo 2

OpenBSD vmm and qcow2 derived disks

Written by Solène, on 27 August 2023.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Let me show you a very practical feature of qcow2 virtual disk format, that is available in OpenBSD vmm, allowing you to easily create derived disks from an original image (also called delta disks).

A derived disk image is a new storage file that will inherit all the data from the original file, without modifying the original ever, it's like stacking a new fresh disk on top of the previous one, but all the changes are now written on the new one.

This allows interesting use cases such as using a golden image to provide a base template, like a fresh OpenBSD install, or create a temporary disks to try changes without harming to original file (and without having to backup a potentially huge file).

This is NOT OpenBSD specific, it's a feature of the qcow2 format, so while this guide is using OpenBSD as an example, this will work wherever qcow2 can be used.

OpenBSD vmctl man page: -b flag

2. Setup §

First, you need to have a qcow2 file with something installed in it, let's say you already have a virtual machine with its storage file /var/lib/vmm/alpine.qcow2.

We will create a derived file /var/lib/vmm/derived.qcow2 using the vmctl command:

# vmctl create -b /var/lib/vmm/alpine.qcow2 /var/lib/vmm/derived.qcow2

That's it! Now you have the new disk that already inherits all the other file data without modifying it ever.

3. Limitations §

The derived disk will stop working if the original file is modified, so once you make derived disks from a base image, you shouldn't modify the base image.

However, it's possible to merge changes from a derived disk to the base image using the qemu-img command:

Red Hat documentation: Rebasing a Backing File of an Image

4. Conclusion §

The derived images can be useful in some scenarios, if you have an image and want to make some experimentation without making a full backup, just use a derived disk. If you want to provide a golden image as a start like an installed OS, this will work too.

One use case I had was with OpenKuBSD, I had a single OpenBSD install as a base image, each VM had a derived disk as their root but removed and recreated at every boot, but they also had a dedicated disk for /home, this allows me to keep all the VMs clean, and I just have a single system to manage.

Manipulate PDF files easily with pdftk

Written by Solène, on 19 August 2023.
Tags: #productivity

Comments on Fediverse/Mastodon

1. Introduction §

I often need to work with PDF, sometimes I need to extract a single page, or add a page, too often I need to rotate pages.

Fortunately, there is a pretty awesome tool to do all of these tasks, it's called PDFtk.

pdftkofficial project website

2. Operations §

Pdftk command line isn't the most obvious out there, but it's not that hard.

2.1. Extracting a page §

Extracting a page requires the cat sub command, and we need to give a page number or a range of pages.

For instance, extracting the pages 11, and from 16 to 18 from the file my_pdf.pdf to a new file export.pdf can be done with the following command:

pdftk my_pdf.pdf cat 11 16-18 output export.pdf

2.2. Merging PDF into a single PDF §

Merging multiple PDFs into a single PDF also uses the sub command cat. In the following example, you will concatenate the PDF first.pdf and second.pdf into a merged.pdf result:

pdftk first.pdf second.pdf cat output merged.pdf

Note that they are concatenated in their order in the command line.

2.3. Rotating PDF §

Pdftk comes with a very powerful way to rotate PDFs pages. You can specify pages or ranges of pages to rotate, the whole document, or only odd/even pages etc...

If you want to rotate all the pages of a PDF clockwise (east), we need to specify a range 1-end, which means first to last page:

pdftk input.pdf rotate 1-endeast output rotated.pdf

If you want to select even or odd pages, you can add the keyword even or odd between the range and the rotation direction: 1-10oddwest or 2-8eveneast are valid rotations.

2.4. Reversing the page ordering §

If you want to reverse how pages are in your PDF, we can use the special range end-1 which will go through pages from the last to the first one, with the sub command cat this will only recreate a new PDF:

pdftk input.pdf cat end-1 output reversed.pdf

3. Conclusion §

Pdftk have some other commands, most people will need to extract / merge / rotate pages, but take a look at the documentation to learn about all pdftk features.

PDF are usually a pain to work with, but pdftk make it very fast and easy to apply transformation on them. What a great tool :-)

Migrating prosody internal storage to SQLite on OpenBSD

Written by Solène, on 18 August 2023.
Tags: #prosody #xmpp #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

As some may know, I'm an XMPP user, an instant messaging protocol which used to be known as Jabber. My server is running Prosody XMPP server on OpenBSD. Recently, I got more users on my server, and I wanted to improve performance a bit by switching from the internal storage to SQLite.

Actually, prosody comes with a tool to switch from a storage to another, but I found the documentation lacking and on OpenBSD the migration tool isn't packaged (yet?).

The switch to SQLite drastically reduced prosody CPU usage on my small server, and went pain free.

Prosody documentation: Prosody migrator

2. Setup §

For the migration to be done, you will need a few prerequisites:

  • know your current storage, which is "internal" by default
  • know the future storage you want to use
  • know where prosody stores its files
  • the migration tool

On OpenBSD, the migration tool can be retrieved by downloading the sources of prosody. If you have the ports tree available, just run make extract in net/prosody and cd into the newly extracted directory. The directory path can be retrieved using make show=WRKSRC.

The migration tool can be found in the subdirectory tools/migration of the sources, the program gmake is required to build the program (it's only replacing a few variables in it, so no worry about a complex setup).

In the migration directory, run gmake, you will obtain the migration tool prosody-migrator.install which is the program you will run for the migration to happen.

3. Prepare the configuration file §

In the migration directory, you will find a file migrator.cfg.lua.install, this is a configuration file describing your current prosody deployment and what you want with the migration, it defaults to a conversion from "internal" to "sqlite" which is what most users will want in my opinion.

Make sure the variable data_path in the file refers to /var/prosody which is the default directory on OpenBSD, and check the hosts in the "input" part which describe the current storage. By default, the new storage will be in /var/prosody/prosody.sqlite.

4. Run the tool §

Once you have the migrator and its configuration file, it's super easy to proceed:

  • Stop the prosody server with rcctl stop prosody
  • Modify /etc/prosody/prosody.cfg.lua to use the sql driver instead of internal
storage = "sql"
sql = {
    driver = "SQLite3";
    database = "prosody.sqlite";
}
  • Backup /var/prosody in case something is going bad
  • Run the migration with lua53 prosody-migrator.install --config ./migrator.cfg.lua.install
  • Verify the file /var/prosody/prosody.sqlite exists and isn't empty
  • Chown /var/prosody/prosody.sqlite to _prosody:_prosody
  • Start the prosody server with rcctl start prosody, check everything is working fine

If you had an error at the migration step, check the logs carefully to check if you missed something, a bad path, maybe.

5. Conclusion §

Prosody comes with a migration tool to switch from a storage backend to another, that's very handy when you didn't think about scaling the system correctly at first.

The migrator can also be used to migrate from the server ejabberd to prosody.

Thanks prx for your report about some missing steps!

Some explanations about OpenBSD memory usage

Written by Solène, on 11 August 2023.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

I regularly see people reporting high memory usage on OpenBSD when looking at some monitoring program output.

Those programs may be not reporting what you think. The memory usage can be accounted in different ways.

Most of the time, the file system cache stored in-memory is added to memory usage, which lead to think about a high memory consumption.

2. How to figure the real memory usage? §

Here are a few methods to gather the used memory.

2.1. Using ps §

You can actually use ps and sum the RSS column and display it as megabytes:

ps auwxx | awk '{ sum+=$6 } END { print sum/1024 }'

You could use the 5th column if you want to sum the virtual memory, which can be way higher than your system memory (hence why it's called virtual).

2.2. Using top §

When running top in interactive mode, you can find a memory line at the top of the output, like this:

Memory: Real: 244M/733M act/tot Free: 234M Cache: 193M Swap: 158M/752M

This means there are 244 MB of memory currently in use, and 158 MB in the swap file.

The cache column displays how much file system data you have cached in memory, this is extremely useful because every time you open a program, this would avoid seeking it on the storage media if it's already in the memory cache, which is way faster. This memory is freed when needed if there are not enough free memory available.

The "free" column only tell you that this ram is completely unused.

The number 733M indicates the total real memory, which includes memory in use that could be freed if required, however if someone find a clearer explanation, I'd be happy to read it.

2.3. Using systat §

The command systat is OpenBSD specific, often overlooked but very powerful, it has many displays you can switch to using left/right arrows, each aspect of the system has its own display.

The default display has a "memory totals in (KB)" area about your real, free or virtual memory.

3. Going further §

Inside the kernel, the memory naming is different, and there are extra categories. You can find them in the kernel file sys/uvm/uvmexp.h:

GitHub page for sys/uvm/uvmexp.h lines 56 to 62

4. Conclusion §

When one looks at OpenBSD memory usage, it's better to understand the various field before reporting a wrong amount, or that OpenBSD uses too much memory. But we have to admit the documentation explaining each field is quite lacking.

Authenticate the SSH servers you are connecting to

Written by Solène, on 05 August 2023.
Tags: #ssh #security

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1. Introduction §

It's common knowledge that SSH connections are secure; however, they always had a flaw: when you connect to a remote host for the first time, how can you be sure it's the right one and not a tampered system?

SSH uses what we call TOFU (Trust On First Use), when you connect to a remote server for the first time, you have a key fingerprint displayed, and you are asked if you want to trust it or not. Without any other information, you can either blindly trust it or deny it and not connect. If you trust it, the key's fingerprint is stored locally in the file known_hosts, and if the remote server offers you a different key later, you will be warned and the connection will be forbidden because the server may have been replaced by a malicious one.

Let's try an analogy. It's a bit like if you only had a post-it with, supposedly, your bank phone number on it, but you had no way to verify if it was really your bank on that number. This would be pretty bad. However, using an up-to-date trustable public reverse lookup directory, you could check that the phone number is genuine before calling.

What we can do to improve the TOFU situation is to publish the server's SSH fingerprint over DNS, so when you connect, SSH will try to fetch the fingerprint if it exists and compare it with what the server is offering. This only works if the DNS server uses DNSSEC, which guarantees the DNS answer hasn't been tampered with in the process. It's unlikely that someone would be able to simultaneously hijack your SSH connection to a different server and also craft valid DNSSEC replies.

2. Setup §

The setup is really simple, we need to gather the fingerprints of each key (they exist in multiple different crypto) on a server, securely, and publish them as SSHFP DNS entries.

If the server has new keys, you need to update its SSHFP entries.

We will use the tool ssh-keygen which contains a feature to automatically generate the DNS records for the server on which the command is running.

For example, on my server interbus.perso.pw, I will run ssh-keygen -r interbus.perso.pw. to get the records

$ ssh-keygen -r interbus.perso.pw.
interbus.perso.pw. IN SSHFP 1 1 d93504fdcb5a67f09d263d6cbf1fcf59b55c5a03
interbus.perso.pw. IN SSHFP 1 2 1d677b3094170511297579836f5ef8d750dae8c481f464a0d2fb0943ad9f0430
interbus.perso.pw. IN SSHFP 3 1 98350f8a3c4a6d94c8974df82144913fd478efd8
interbus.perso.pw. IN SSHFP 3 2 ec67c81dd11f24f51da9560c53d7e3f21bf37b5436c3fd396ee7611cedf263c0
interbus.perso.pw. IN SSHFP 4 1 cb5039e2d4ece538ebb7517cc4a9bba3c253ef3b
interbus.perso.pw. IN SSHFP 4 2 adbcdfea2aee40345d1f28bc851158ed5a4b009f165ee6aa31cf6b6f62255612

You certainly noted I used an extra dot, this is because they will be used as DNS records, so either:

  • Use the full domain name with an extra dot to indicate you are not giving a subdomain
  • Use only the subdomain part, this would be interbus in the example

If you use interbus.perso.pw without the dot, this would be for the domain interbus.perso.pw.perso.pw because it would be treated as a subdomain.

Note that -r arg isn't used for anything but the raw text in the output, this doesn't make ssh-keygen fetch the keys of a remote URL.

Now, just add each of the generated entries in your DNS.

3. How to use SSHFP on your OpenSSH client §

By default, if you connect to my server, you should see this output:

> ssh interbus.perso.pw
The authenticity of host 'interbus.perso.pw (46.23.92.114)' can't be established.
ED25519 key fingerprint is SHA256:rbzf6iruQDRdHyi8hRFY7VpLAJ8WXuaqMc9rb2IlVhI.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? 

It's telling you the server isn't known in known_hosts yet, and you have to trust it (or not, but you wouldn't connect).

However, with the option VerifyHostKeyDNS set to yes, the fingerprint will automatically be accepted if the one offered is found in an SSHFP entry.

As I explained earlier, this only works if the DNS answer is valid with regard to DNSSEC, otherwise, the setting "VerifyHostKeyDNS" automatically falls back to "ask", asking you to manually check the DNS SSHFP found and if you want to accept or not.

For example, without a working DNSSEC, the output would look like this:

$ ssh -o VerifyHostKeyDNS=yes interbus.perso.pw
The authenticity of host 'interbus.perso.pw (46.23.92.114)' can't be established.
ED25519 key fingerprint is SHA256:rbzf6iruQDRdHyi8hRFY7VpLAJ8WXuaqMc9rb2IlVhI.
Matching host key fingerprint found in DNS.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])?

With a working DNSSEC, you should immediately connect without any TOFU prompt, and the host fingerprint won't be stored in known_hosts.

4. Conclusion §

SSHFP is a simple mechanism to build a chain of trust using an external service to authenticate the server you are connecting to. Another method to authenticate a remote server would be to use an SSH certificate, but I'll keep that one for later.

5. Going further §

We saw that VerifyHostKeyDNS is reliable, but doesn't save the fingerprint in the file ~/.ssh/known_hosts, which can be an issue if you need to connect later to the same server if you don't have a working DNSSEC resolver, you would have to trust blindly the server.

However, you could generate the required output from the server to be used by the known_hosts when you have DNSSEC working, so next time, you won't only rely on DNSSEC.

Note that if the server is replaced by another one and its SSHFP records updated accordingly, this will ask you what to do if you have the old keys in known_hosts.

To gather the fingerpints, connect on the remote server, which will be remote-server.local in the example and add the command output to your known_hosts file:

ssh-keyscan localhost 2>/dev/null | sed 's/^localhost/remote-server/'

We omit the .local in the remote-server.local hostname because it's a subdomain of the DNS zone. (thanks Francisco Gaitán for spotting it).

Basically, ssh-keyscan can remotely gather keys, but we want the local keys of the server, then we need to modify its output to replace localhost by the actual server name used to ssh into it.

Turning a 15 years old laptop into a children proof retrogaming station

Written by Solène, on 24 July 2023.
Tags: #gaming #life #linux

Comments on Fediverse/Mastodon

1. Introduction §

This article explains a setup I made for our family vacation place, I wanted to turn an old laptop (a Dell Vostro 1500 from 2008) into a retrogaming station. That's actually easy to do, but I wanted to make it "childproof" so it will always work even if we let children alone with the laptop for a moment, that part was way harder.

This is not a tutorial explaining everything from A to Z, but mostly what worked / didn't work from my experimentation.

2. Choosing an OS §

First step is to pick an operating system. I wanted to use Alpine, with the persistent mode I described last week, this would allow having nothing persistent except the ROMs files. Unfortunately, the packages for Retroarch on Alpine were missing the cores I wanted, so I dropped Alpine. A retroarch core is the library required to emulate a given platform/console.

Then, I wanted to give FreeBSD a try before switching to a more standard Linux system (Alpine uses the libc musl which makes it "non-standard" for my use case). The setup was complicated as FreeBSD barely do anything by itself at install time, but after I got a working desktop, Retroarch had an issue, I couldn't launch any game even though the cores were loaded. I can't explain why this wasn't working, everything seemed fine. On top of this issue, game pad support have been really random, so I gave up.

Finally, I installed Debian 12 using the netinstall ISO, and without installing any desktop and graphical server like X or Wayland, just a bare Debian.

3. Retroarch on a TTY §

To achieve a more children-proof environment, I decided to run Retroarch directly from a TTY, without a graphical server.

This removes a lot of issues:

  • no desktop you could lock
  • no desktop you could log out from
  • no icons / no menus to move / delete
  • nothing fancy, just retroarch in full screen

In addition to all the benefits listed above, this also reduces the emulation latency, and makes the system lighter by not having to render through X/Wayland. I had to install the retroarch package and some GL / vulkan / mesa / sdl2 related packages to have it working.

One major painful issue I had was to figure a way to start retroarch in tty1 at boot. Actually, this is really hard, especially since it must start under a dbus session to have all features enabled.

My solution is a hack, but good enough for the use case. I overrode the getty@tty1 service to automatically log in the user, and modified the user ~/.bashrc file to exec retroarch. If retroarch quits, the tty1 would be reset and retroarch started again, and you can't escape it.

4. Retroarch configuration §

I can't describe all the tweaks I did in retroarch, some were for pure enhancement, some for "hardening". Here is a list of things I changed:

  • pre-configure all the controllers you want to use with the system
  • disable all menus except the playlists, they automatically group games by support which is fine
  • set the default core for each playlist, this removes an extra weird step for non-technical users
  • set a special shortcut to access the quick menu from the controller, something like select+start should be good, this allows to drop/pause a game from the controller

In addition to all of that, there is a lovely kiosk mode. This basically just allow you to password protect all the settings in Retroarch, once you are done with the configuration, enable the kiosk mode, nothing can be changed (except putting a ROM in favorite).

5. Extra settings §

I configured a few more extra things to make the experience more children proof.

5.1. Grub config §

Grub can be a major issue if a children boots up the laptop but press a key at grub time. Just set GRUB_TIMEOUT=0 to disable the menu prompt, it will directly start into Debian.

5.2. Disabled networking §

The computer doesn't need to connect to any network, so I disabled all the services related to network, this reduced the boot time by a few seconds, and will prevent anything weird from happening.

5.3. Bios lock §

It may be wise to lock the bios, so in case you have children who know how to boot something on a computer, they wouldn't even be able to do that. This also prevent mistakes in the bios, better be careful. Don't lose that password.

5.4. Plymouth splash screen §

If you want your gaming console to have this extra thing that will turn the boring and scary boot process text into something cool, you can use Plymouth.

I found a nice splash screen featuring Optimus head from Transformers while the system is booting, this looks pretty cool! And surely, this will give the system some charm and persona compared to systemd boot process. This delays the boot by a few seconds though.

6. Conclusion §

Retroarch is a fantastic software for emulation, and you can even run it from a TTY for lower latency. Its controller mapping is really smart, you have to configure each controller against some kind of "reference" controller, and then each core will have a map from the reference controller to convert into the console controller you are emulating. This mean you don't have to map your controller for each console, just once.

Doing a children proof kiosk computer wasn't easy, I'm sure there is room for improvement, but I'm happy that I turned a 15 years old laptop into something useful that will bring joy for kids, and memories for adults, without them fearing that the system will be damaged by kids (except physical damage but hey, I won't put the thing in a box).

Now, I have to do some paint job for the laptop behind-the-screen part to look bright and shiny :)

Old Computer Challenge v3: postmortem

Written by Solène, on 17 July 2023.
Tags: #occ #occ23 #oldcomputerchallenge

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1. Challenge report §

Hi! I've not been very communicative about my week during the Old Computer Challenge v3, the reason is that I failed it. Time for a postmortem (analysis of what happened) to understand the failure!

For the context, the last time I was using a restricted hardware was for the first edition of the challenge two years ago. Last year challenge was about reducing Internet connectivity.

2. Wasn't prepared §

I have to admit, I didn't prepare anything. I thought I could simply limit the requirements on my laptop, either on OpenBSD or openSUSE and enjoy the challenge. It turned out it was more complicated than that.

  • OpenBSD memory limitation code wasn't working on my system for some reason (I should report this issue)
  • openSUSE refused to boot with 512 MB of memory under 30 minutes, even by adding swap, and I couldn't log in through GDM once there

I had to figure a backup plan, which turned to be using Alpine Linux installed on a USB memory stick, memory and core number restriction worked out of the box, figuring how to effectively reduce the frequency was hard, but I did it finally.

From this point, I had a non-encrypted Alpine Linux on a poor storage medium. What would I do with this? Nothing much.

3. Memory limitation §

It turns out that in 2 years, my requirements evolved a bit. 512 MB wasn't enough to use a web browser with JavaScript, and while I thought it wouldn't be such a big deal, it WAS.

I regularly need to go on some websites, doing it on my non-trusted smartphone is a no-go, so I need a computer, and Firefox on 512 MB just doesn't work. Chromium almost work, but it depends on the page, and WebKit browser often didn't work well enough.

Here is a sample of websites I needed to visit:

  • OVH web console
  • Patreon web page
  • Bank service
  • Some online store
  • Mastodon (I have such a huge flow that CLI tools doesn't work well for me)
  • Kanban tool
  • Deepl for translation
  • Replying to people on some open source project Discourse forums
  • Managing stuff in GitHub (gh tool isn't always on-par with the web interface)

For this reason, I often had to use my "work" computer to do the tasks, and ended up inadvertently continuing on this computer :(

In addition to web browsing, some programs like LanguageTool (a java GUI spellcheck program) required too much memory to be started, so I couldn't even spell check my blog posts (Aspell is not as complete as LanguageTool).

4. CPU limitation §

At first when I thought about the rules for the 3rd edition, the CPU frequency seemed to be the worst part. In practice, the system was almost swapping continuously but wasn't CPU bound. Hardware acceleration was fast enough to play videos smoothly.

If you can make good use of the 512 MB of memory, you certainly won't have CPU problems.

5. Security issues §

This is not related to the challenge itself, but I felt a bit stuck with my untrusted Alpine Linux, I have some ssh / GPG keys that are secured on two systems and my passwords, I almost can't do anything without them, and I didn't want to take the risk of compromising my security chain for the challenge.

In fact, since I started using Qubes OS, I started being reluctant to mix all my data on a single system, even the other one I'm used to being working with (which has all the credentials too), but Qubes OS is the anti-oldcomputerchallenge as you need to throw the more hardware you can to make it useful.

6. Not a complete failure §

However, the challenge wasn't such a complete failure for me. While I can't say I played by the rules, it definitely helped me to realize the changes in my computer use over the last years. This was the point when I started the "offline laptop" project three years ago, which transformed into the old computer challenge the year after.

I tried to use less the computer as I wasn't able to fulfill the challenge requirements, and did some stuff IRL at home and outside, the week went SUPER FAST, I was astonished to realize it's already over. This also forced me to look for solutions, so I spent *a LOT* of time trying to make Firefox fit in 512 MB, TLDR it didn't work.

The LEAST memory I'd need nowadays is 1 GB of memory, it's still not much compared to what we have nowadays (my main system has 32 GB), but it's twice the first requirements I've set.

7. Conclusion §

It seems everyone had a nice week with the challenge, I'm very happy to see the community enjoying this every year. I may not be the challenge paragon for this year, but it was useful to me, and since then I couldn't stop thinking about how to improve my computer usage.

Next challenge should be two weeks long :)

How-to install Alpine Linux in full ram with persistency

Written by Solène, on 14 July 2023.
Tags: #immutability #linux #alpine

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1. Introduction §

In this guide, I'd like to share with you how to install Alpine Linux, so it runs entirely from RAM, but using its built-in tool to handle persistency. Perfect setup for a NAS or router, so you don't waste a disk for the system, and this can even be used for a workstation.

Alpine Linux official project website

Alpine Linux wiki: Alpine local backup

2. The plan §

Basically, we want to get the Alpine installer on a writable disk formatted in FAT instead of a read only image like official installers, then we will use the command lbu to handle persistency, and we will see what need to be configured to have a working system.

This is only a list of steps, they will be detailed later:

  1. boot from an Alpine Installer (if you are using Alpine, you don't need too)
  2. format an usb memory drive with an ESP partition and make it bootable
  3. run setup-bootloader to copy the bootloader from the installer to the freshly formatted drive
  4. reboot on the usb drive
  5. run setup-alpine
  6. you are on your new Alpine system
  7. run lbu commit to make changes persistent across reboot
  8. make changes, run lbu commit again
A mad scientist Girl with a t-shirt labeled "rare t-shirt" is looking at a penguin strapped on a Frankenstein like machine, with his head connected to a huge box with LBU written on it.
A mad scientist Girl with a t-shirt labeled "rare t-shirt" is looking at a penguin strapped on a Frankenstein like machine, with his head connected to a huge box with LBU written on it.

Artwork above by Prahou

3. The setup §

3.1. Booting Alpine §

For this step you have to download an Alpine Linux installer, take the one that suits your needs, if unsure, take the "Extended" one. Don't forget to verify the file checksum.

Once you have the ISO file, create the installation media:

Alpine Linux documentation: Using the image

Now, boot your system using your brand-new installer.

3.2. Writable boot media creation §

In this step, we will need to boot on the Alpine installer to create a new Alpine installer, but writable.

You need another USB media for this step, the one that will keep your system and data.

On Alpine Linux, you can use setup-alpine to configure your network, key map and a few things for the current system. You only have to say "none" when you are asked what you want to install, where, and if you want to store the configuration somewhere.

Run the following commands on the destination USB drive (networking is required to install a package), this will format it and use all the space as a FAT32 partition. In the example below, the drive is /dev/sdc.

apk add parted
parted /dev/sdc -- mklabel gpt
parted /dev/sdc -- mkpart ESP fat32 1MB 100%
parted /dev/sdc -- set 1 esp on

This creates a GPT table on /dev/sdc, then creates a first partition as FAT32 from the first megabyte up to the full disk size, and finally marks it bootable. This guide is only for UEFI compatible systems.

We actually have to format the drive as FAT32, otherwise it's just a partition type without a way to mount it as FAT32:

mkfs.vfat /dev/sdc1
modprobe vfat

Final step, we use an Alpine tool to copy the bootloader from the installer to our new disk. In the example below, your installer may be /media/usb and the destination /dev/sdc1, you could figure the first one using mount.

setup-bootable /media/usb /dev/sdc1

At this step, you made a USB disk in FAT32 containing the Alpine Linux installer you were using live. Reboot on the new one.

3.3. System installation §

On your new installation media, run setup-alpine as if you were installing Alpine Linux, but answer "none" when you are asked which disk you want to use. When asked "Enter where to store configs", you should be prompted your new device by default, accept. Immediately, after, you will be prompted for an APK cache, accept.

At this point, we can say Alpine is installed! Don't reboot yet, you are already on your new system!

Just use it, and run lbu commit when you need to save changes done to packages or /etc/. lbu commit creates a new tarball in your USB disk containing a list of files configured in /etc/apk/protected_paths.d/, and this tarball is loaded at boot time, and will install your package list quickly from the local cache.

Alpine Linux wiki: Alpine local backup (lbu command documentation)

Please take extra care that if you include more files, everything you commit the changes, they have to be stored on your USB media. You could modify the fstab to add an extra disk/partition for persistent data on a performant drive.

4. Updating the kernel §

The kernel can't be upgraded using apk, you have to use the script update-kernel that will create a "modloop" file in the boot partition which contains the boot image. You can't rollback this file.

You will need a few gigabytes in your in-memory filesystem, or use a temporary build directory by affecting TMPDIR variable to a persistent storage.

By default, tmpfs on root is set to 1 GB, this can be increased given you have enough memory using the command: mount -o remount,size=6G /.

The script should have the boot directory as a parameter, so it should look like update-kernel /media/usb/boot in a default setup, if you use an external partition, this would look like env TMPDIR=/mnt/something/ update-kernel /media/usb/boot.

4.1. Extra configuration §

Here is a list of tweaks to improve your experience!

4.1.1. keep last n configuration §

By default, lbu will only keep the last version you save, by settingBACKUP_LIMIT to a number n, you will always have the last n versions of your system stored in the boot media, this is practical if you want to roll back a change.

4.1.2. apk repositories §

Edit /etc/apk/repositories to uncomment the community repository.

4.1.3. fstab check §

Edit /etc/fstab to make sure the disk you are using is explicitly configured using a UUID entry, if you only have this:

/dev/cdrom	/media/cdrom	iso9660	noauto,ro 0 0
/dev/usbdisk	/media/usb	vfat noauto,ro 0 0

This mean your system may have troubles if you use it on a different computer or that you plug another USB disk in it. Fix by using the UUID of your partition, you can find it using the program blkid from the eponym package, and fix the fstab like this:

UUID=61B2-04FA	/media/persist	vfat	noauto,ro 0 0
/dev/cdrom	/media/cdrom	iso9660	noauto,ro 0 0
/dev/usbdisk	/media/usb	vfat noauto,ro 0 0

This will ALWAYS mount your drive as /media/persist.

If you had to make the change, you need to make some extra changes to keep things coherent:

  • set LBU_MEDIA=persist into /etc/lbu/lbu.conf
  • umount the drive in /media and run mkdir -p /media/persist && mount -a, you should have /media/persist with data in it
  • run lbu commit to save the changes

4.1.4. desktop setup §

You can install a graphical desktop, this can easily be done with these commands:

setup-desktop xfce
setup-xorg-base

Due to a bug, we have to re-enable some important services, otherwise you would not have networking at the next boot:

rc-update add hwdrivers sysinit

Alpine bug report #9653

You may want to enable the display manager at boot, which may be lightdm, gdm or sddm depending on your desktop:

rc-update add lightdm

4.1.5. user persistency §

If you added a user during setup-alpine, its home directory has been automatically added to /etc/apk/protected_paths.d/lbu.list, when you run lbu commit, its whole home is stored. This may not be desired.

If you don't want to save the whole home directory, but only a selection of files/directories, here is how to proceed:

  1. edit /etc/apk/protected_paths.d/lbu.list to remove the line adding your user directory
  2. you need to create the user directory at boot with the correct permissions: echo "install -d -o solene -g solene -m 700 /home/solene" | doas tee /etc/local.d/00-user.start
  3. in case you have some persistency set at least one user sub directories, it's important to fix the permissions of all the user data after the boot: echo "chown -R solene:solene /home/solene | doas tee -a /etc/local.d/00-user.start
  4. you need to mark this script as executable: doas chmod +x /etc/local.d/00-user.start
  5. you need to run the local scripts at boot time: doas rc-update add local
  6. save the changes: doas lbu commit

I'd recommend the use of a directory named Persist and adding it to the lbu list. Doing so, you have a place to store some important data without having to save all your home directory (including garbage such as cache). This is even nicer if you use ecryptfs as explained below.

4.1.6. extra convenience §

Because Alpine Linux is packaged in a minimalistic manner, you may have to install a lot of extra packages to have all the fonts, icons, emojis, cursors etc... working correctly as you would expect for a standard Linux desktop.

Fortunately, there is a community guide explaining each section you may want to configure.

Alpine Linux wiki: Post installation

4.1.7. Set X default keyboard layout §

Alpine insists of you using a qwerty desktop for X until you log into your session, this can be complicated to type passwords.

You can create a file /etc/X11/xorg.conf.d/00-keyboard.conf like in the linked example and choose your default keyboard layout. You will have to create the directories /etc/X11/xorg.conf.d first.

Arch Linux wiki: Keyboard configuration

4.1.8. encrypted personal directory §

You could use ecryptfs to either encrypt the home partition of your user, or just give it a Private directory that could be unlocked on demand AND made persistent without pulling all the user files at every configuration commit.

$ doas apk add ecryptfs-utils
$ doas modprobe ecryptfs
$ ecryptfs-setup-private
Enter your login passphrase [solene]:
Enter your mount passphrase [leave blank to generate one]:
[...]
$ doas lbu add $HOME/.Private
$ doas lbu add $HOME/.ecryptfs
$ echo "install -d -o solene -g solene -m 700 /home/solene/Private" | doas tee /etc/local.d/50-ecryptfs.start
$ doas chmod +x /etc/local.d/50-ecryptfs.start
$ doas rc-update add local
$ doas lbu commit

Now, when you need to access your private directory, run ecryptfs-mount-private and you have your $HOME/Private directory which is encrypted.

You could use ecryptfs to encrypt the whole user directory, this requires extra steps and changes into /etc/pam.d/base-auth, don't forget to add /home/.ecryptfs to the lbu include list.

Using ecryptfs guide

5. Security §

Let's be clear, this setup isn't secure! The weak part is the boot media, which doesn't use secure boot, could easily be modified, and has nothing encrypted (except the local backups, but NOT BY DEFAULT).

However, once the system has booted, if you remove the boot media, nothing can be damaged as everything lives in memory, but you should still use passwords for your users.

6. Conclusion §

Alpine is a very good platform for this kind of setup, and they provide all the tools out of the box! It's a very fun setup to play with.

Don't forget that by default everything runs from memory without persistency, so be careful if you generate data you don't want to lose (passwords, downloads, etc...).

7. Going further §

The lbu configuration can be encrypted, this is recommended if you plan to carry your disk around, especially if it contains sensitive data.

You can use the fat32 partition only for the bootloader and the local backup files, but you could have an extra partition that could be mounted for /home or something, and why not a layer of LUKS for encryption.

You may want to use zram if you are tight on memory, this creates a compressed block device that could be used for swap, it's basically compressed RAM, it's very efficient but less useful if you have a slow CPU.

Introduction to immutable Linux systems

Written by Solène, on 12 July 2023.
Tags: #immutability #linux

Comments on Fediverse/Mastodon

1. Introduction §

If you reach this page, you may be interested into this new category of Linux distributions labeled "immutable".

In this category, one can find by age (oldest → youngest) NixOS, Guix, Endless OS, Fedora Silverblue, OpenSUSE MicroOS, Vanilla OS and many new to come.

I will give examples of immutability implementation, then detail my thoughts about immutability, and why I think this naming can be misleading. I spent a few months running all of those distributions on my main computers (NAS, Gaming, laptop, workstation) to be able to write this text.

2. What's immutability? §

The word immutability itself refers to an object that can't change.

However, when it comes to an immutable operating system, the definition immediately become vague. What would be an operating system that can't change? What would you be supposed to do with it?

We could say that a Linux LIVE-CD is immutable, because every time you boot it, you get the exact same programs running, and you can't change anything as the disk media is read only. But while the LIVE-CD is running, you can make changes to it, you can create files and directories, install packages, it's not stuck in an immutable state.

Unfortunately, this example was nice but the immutability approach by those Linux distribution is totally different, so we need to think a bit further.

There are three common principles in these systems:

  • system upgrades aren't done on the live system
  • packages changes are applied on the next boot
  • you can roll back a change

Depending on the implementation, a system may offer more features. But this list is what a Linux distribution should have to be labelled "immutable" at the moment.

3. Immutable systems comparison §

Now we found what are the minimum requirements to be called immutable, let's go through each implementation, by their order of appearance.

3.1. NixOS / Guix §

In this section, I'm mixing NixOS and Guix as they both rely on the same implementation. NixOS is based on Nix (first appearance in 2003), which has been forked into early 2010s into the Guix package manager to be 100% libre, which gave birth to an eponym operating system also 100% free.

NixOS official project website

Guix official project website

Jonathan Lorimer's blog post explaining Eelco Dolstra's thesis about Nix

These two systems are really different than a traditional Unix like system we are used to, and immutability is a main principle. To make it quick, they are based on their package manager (being Nix or Guix) that contains every package or built file into a special read-only directory (where only the package manager can write) where each package has its own unique entry, and the operating system itself is a byproduct of the package manager.

What does that imply? If the operating system is built, this is because it's made of source code, you literally describe what you want your system to be in a declarative way. You have to list users, their shells, installed packages, running services and their configurations, partitions to mount with which options etc... Fortunately, it's made a lot easier by the use of modules which provide sane defaults, so if you create a user, you don't have to specify its UID, GID, shell, home etc...

So, as the system is built and stored in the special read-only directory, all your system is derived from that (using symbolic links), so all the files handled by the package manager are read-only. A concrete example is that /etc/fstab or /bin/sh ARE read-only, if you want to make a change in those, you have to do it through the package manager.

I'm not going into details, because this store based package manager is really different than everything else but:

  • you can switch between two configurations on the fly as it's just a symlink dance to go from a configuration to another
  • you can select your configuration at boot time, so you can roll back to a previous version if something is wrong
  • you can't make change to a package file or system file as they are read only
  • the mount points except the special store directory are all mutable, so you can write changes in /home or /etc or /var etc... You can remove the system symlinks by a modified version, but you can't modify the symlink source itself.

This is the immutability as seen through the Nix lens.

I've spent a few years running NixOS systems, this is really a blast for me, and the best "immutable" implementation around, but unfortunately it's too different, so its adoption rate is very low, despite all the benefits.

NixOS forum: My issues when pushing NixOS to companies

3.2. Endless OS §

While this one is not the oldest immutable OS around, it's the first one to be released for the average user, while NixOS and Guix are older but for a niche user category. The company behind Endless OS is trying to offer a solid and reliable system, free and open source, that can works without Internet, to be used in countries with a low Internet / powergrid coverage. They even provide a version with "offline internet included" containing Wikipedia dumps, class lessons and many things to make a computer useful while offline (I love their work).

Endless OS official project website

Endless OS is based on Debian, but uses the OSTree tool to make it immutable. OSTree allows you to manage a core system image, and add layers on top of it, think of packages as layers. But it can also prepare a new system image for the next boot.

With OSTree, you can apply package changes in a new version of the system that will be available at next boot, and revert to a previous version at boot time.

The partitions are mounted writable, except for /usr, the land of packages handled by OSTree, which is mounted read-only. There are no rollbacks possible for /etc.

Programs meant to be for the user (not the packages to be used by the system like grub, X display or drivers) are installed from Flatpak (which also uses OSTree, but unrelated to the system), this avoids the need to reboot each time you install a new package.

My experience with Endless OS is mixed, it is an excellent and solid operating system, it's working well, never failed, but I'm just not the target audience. They provide a modified GNOME desktop that looks like a smartphone menu, because this is what most non-tech users are comfortable with (but I hate it). And installing DevOps tools isn't practical but not impossible, so I keep Endless OS for my multimedia netbook and I really enjoy it.

3.3. Fedora Silverblue §

This linux distribution is the long descendant of Project Atomic, an old initiative to make Fedora / CentOS/ RHEL immutable. It's now part of the Fedora releases along with Fedora Workstation.

Project Atomic website

Fedora Silverblue project website

Fedora Silverblue is also using OSTree, but with a twist. It's using rpm-OSTree, a tool built on top of OSTree to let your RPM packages apply the changes through OSTree.

The system consists of a single core image for the release, let's say fedora-38, and for each package installed, a new layer is added on top of the core. At anytime, you can list all the layers to know what packages have been installed on top of the core, if you remove a package, the whole stack is generated again (which is terribly SLOW) without the package, there is absolutely no leftover after a package removal.

On boot, you can choose an older version of the system, in case something broke after an upgrade. If you install a package, you need to reboot to have it available as the change isn't applied on the current booted system, however rpm-OSTree received a nice upgrade, you can temporarily merge the changes of the next boot into the live system (using a tmpfs overlay) to use the changes.

The mountpount management is a bit different, everything is read-only except /etc/, /root and /var, but your home directory is by default in /var/home which sometimes breaks expectations. There are no rollbacks possible for /etc.

As installing a new package is slow due to rpm-OSTree and requires a reboot to be fully usable (the live change back port store the extra changes in memory), they recommend to use Flatpak for programs, or toolbox, some kind of wrapper that create a rootless fedora container where you can install packages and use it in your terminal. toolbox is meant to provide development libraries or tool you wouldn't have in Flatpak, but that you wouldn't want to install in your base Fedora system.

toolbox website

My experience with Fedora Silverblue has been quite good, it's stable, the updates are smooth even if they are slow. toolbox was working fine despite I don't find this practical.

3.4. OpenSUSE MicroOS §

This spin of OpenSUSE Tumbleweed (rolling-release OpenSUSE) features immutability, but with its own implementation. The idea of MicroOS is really simple, the whole system except a few directories like /home or /var lives on a btrfs snapshot, if you want to make a change to the system, the current snapshot is forked into a new snapshot, and the changes are applied there, ready for the next boot.

OpenSUSE MicroOS official project website

What's interesting here is that /etc IS part of the snapshots, and can be roll backed, which wasn't possible in the OSTree based systems. It's also possible to make changes to any file of the file system (in a new snapshot, not the live one) using a shell, which can be very practical for injecting files to solve a driver issue. The downside it's not guaranteed that your system is "pure" if you start making changes, because they won't be tracked, the snapshots are just numbered, and you don't know what changes were made in each of them.

Changes must be done through the command transactional-update which do all the snapshot work for you, and you could either manipulate package by adding/removing a package, or just start a shell in the new snapshot to make all the changes you want. I said /etc is part of the snapshots, it's true, but it's never read-only, so you could make a change live in /etc, then create a new snapshot, the change would be immediately inherited. This can create troubles if you roll back to a previous state after an upgrade if you also made changes to /etc just before.

The default approach of MicroOS is disturbing at first, a reboot is planned every day after a system update, this is because it's a rolling-release system and there are updates every day, and you won't benefit from them until you reboot. While you can disable this automatic reboot, it makes sense to use the newest packages anyway, so it's something to consider if you plan to use MicroOS.

There is currently no way to apply the changes into the live system (like Silverblue is offering), it's still experimental, but I'm confident this will be doable soon. As such, it's recommended to use distrobox to use rootless containers of various distributions to install your favorite tools for your users, instead of using the base system packages. I don't really like this because this adds maintenance, and I often had issues of distrobox refusing to start a container after a reboot, I had to destroy and recreate it entirely to solve.

distrobox GitHub project page

My experience with OpenSUSE MicroOS has been wonderful, it's in dual-boot with OpenBSD on my main laptop, it's my Linux Gaming OS, and it's also my NAS operating system, so I don't have to care about updates. I like that the snapshots system doesn't restrict me, while OSTree systems just doesn't allow you to make changes without installing a package.

3.5. Vanilla OS §

Finally, the really new (but mature enough to be usable) system in the immutable family is Vanilla OS based on Ubuntu (but soon on Debian), using ABroot for immutability. With Vanilla OS, we have another implementation that really differs from what we saw above.

Vanilla OS project website

ABroot named is well thought, the idea is to have a root partition A, another root partition B, and a partition for persistent data like /home or /var.

Here is the boot dance done by ABroot:

  • first boot is done on A, it's mounted in read-only
  • changes to the system like new packages or file changes in /etc are done on B (and can be applied live using a tmpfs overlay)
  • upon reboot, if previous boot was A, you boot on B, then if the boot is successful, ABroot scan for all the changes between A and B, and apply all the changes from B to A
  • when you are using your system, until you make a change, A and B are always identical

This implementation has downsides, you can only roll back a change until you boot on the new version, then the changes are also applied on the previous boot, and you can't roll back. This implementation mostly protects you from a failing upgrade, or if you made changes and tried them live, but you prefer to rollback.

Vanilla OS features the package manager apx, written by distrobox author. That's for sure an interesting piece of software, allowing your non-root user to install packages from many distributions (arch linux, fedora, ubuntu, nix, etc...) and integrates them into the system as if they were installed locally. I suppose it's some kind of layer on top of distrobox.

apx package manager GitHub project page

My experience wasn't very good, I didn't find ABroot to be really useful, and the version 22.10 I tried was using an old Ubuntu LTS release which didn't make my gaming computer really happy. The overall state of Vanilla OS, ABroot and apx is that they are young, I think it can become a great distribution, but it still has some rough edges.

3.6. Alpine Linux (with LBU) §

I've been told that it was possible to achieve immutability on Alpine Linux using the "lbu" command.

Alpine Linux wiki: Local backup

I don't want to go much into details, but here is the short version: you can use Alpine Linux installer as a base system to boot from, and create tarballs of "saved configurations" that are automatically applied upon boot (it's just tarred directories and some automation to install packages). At every boot, everything is untarred again, and packages are installed again (you should use an apk cache directory), everything in live memory, fully writable.

What does this achieve? You always start from a clean state, changes are applied on top of it at every boot, you can roll back the changes and start fresh again. Immutability as we defined above here isn't achieved because changes are applied on the base system, but it's quite close to fulfill (my own) requirements.

I've been using it a few days only, not as my main system, and it requires a very good understanding of what you are doing because the system is fully in memory, and you need to take care about what you want to save/restore, which can create big archives.

On top of that, it's poorly documented.

4. Pros, Cons and Facts §

Now I gave some details about all the major immutable systems (Linux based) around, I think it's time to list the real pros and cons I found from my experimentation.

4.1. Pros §

  • you can roll back changes if something went wrong.
  • transactional-updates allows you to keep the system running correctly during packages changes.

4.2. Cons §

  • configuration management tool (ansible, salt, puppet etc..) integrate VERY badly, they received updates to know how to apply package changes, but you will mostly hit walls if you want to manage those like regular systems.
  • having to reboot after a change is annoying (except for NixOS and Guix which don't require rebooting for each change).
  • OSTree based systems aren't flexible, my netbook requires some extra files in alsa directories to get sound (fortunately Endless OS have them!), you just can't add the files without making a package deploying them.
  • blind rollbacks, it's hard to figure what was done in each version of the system, so when you roll back it's hard to figure what you are doing exactly.
  • it can be hard to install programs like Nix/Guix which require a directory at the root of the file system, or install non-packaged software system-wide (this is often bad practice, but sometimes a necessary evil).

4.3. Facts §

  • immutability is a lie, many parts of the systems are mutable, although I don't know how to describe this family with a different word (transactional something?).
  • immutable doesn't imply stateless.
  • NixOS / Guix are doing it right in my opinion, you can track your whole system through a reliable package manager, and you can use a version control system on the sources, it has the right philosophy from the ground up.
  • immutability is often associated with security benefits, I don't understand why. If someone obtains root access on your system, they can still manipulate the live system and have fun with the /boot partition, nothing prevent them to install a backdoor for the next boot.
  • immutability requires discipline and maintenance, because you have to care about the versioning, you have extra programs like apx / distrobox / devbox that must be updated in parallel of the system (while this is all integrated into NixOS/Guix).

5. Conclusion §

Immutable operating systems are making the news in our small community of open source systems, but behind this word lies many implementations with different use cases. The word immutable certainly creates expectations from users, but it's really nothing more than transactional updates for your operating system, and I'm happy we can have this feature now.

But transactional updates aren't new, I think it started a while ago with Solaris and ZFS allowing you to select a system snapshot at boot time, then I'm quite sure FreeBSD implemented this a decade ago, and it turns out that on any linux distribution with regular btrfs snapshots you could select a snapshot at boot time.

Previous blog post about booting on a BTRFS snapshot without any special setup

In the end, what's REALLY new is the ability to apply a transactional change on a non-live environment, integrates this into the bootloader, and give the user the tooling to handle this easily.

6. Going further §

I recommend reading the blog post "“Immutable” → reprovisionable, anti-hysteresis" by Colin Walters.

“Immutable” → reprovisionable, anti-hysteresis

Easily use your remote scanner on Linux (Qubes OS guide)

Written by Solène, on 11 July 2023.
Tags: #qubesos #scanner #networking

Comments on Fediverse/Mastodon

1. Introduction §

Hi, this is a quick guide explaining how to use a network scanner on Qubes OS (or Linux/BSD in general).

I'll be using a network printer / scanner Brother MFC-1910W in the example.

2. Setup §

2.1. Specific Qubes OS §

For Qubes OS, the simplest way to proceed is to use the qube sys-net (which is UNTRUSTED) to proceed with the scanner operations. Scanning in it isn't less secure than having a dedicated qube as the network traffic isn't encrypted toward the scanner, this also ease a lot the network setup.

All the instructions below will be done in sys-net, with the root user.

Note that sys-net should be either an AppVM with persistent /home or a fully disposable system, so you will have to do all the commands every time you need your scanner. If you need it really often (I use mine once in a while), you may want to automate this in the template used by sys-net.

2.2. Instructions §

We need to install the program sane-airscan used to discover network scanners, and also all the backends/drivers for devices. On Fedora, this can be done using the following command, the package list may differ for other systems.

# dnf install sane-airscan sane-backends sane-backends-drivers-cameras sane-backends-drivers-scanners

Make sure the service avahi-daemon is installed and running, the default Qubes OS templates have it, but not running. It is required for network devices discovery.

# systemctl start avahi-daemon

An extra step is required, avahi requires the port UDP/5353 to be opened on the system to receive discovery replies, if you don't do that, you won't find your network scanner (this is also required for printers).

You need to figure the network interface name of your network, open a console and type ip -4 -br a | grep UP, the first column is the interface name, the lines starting by vif can be discarded. Run the following command, and make sure to replace INTERFACE_NAME by the real name you just found.

For Qubes OS 4.1:

# iptables -I INPUT 1 -i INTERFACE_NAME -p udp --dport 5353 -j ACCEPT

For Qubes OS 4.2:

# nft add rule qubes custom-input udp dport 5353 accept

Now, we should be able to discover the scanner, the following command should output a line with a device name and network address:

# airscan-discover

For me, the output looks like this:

[devices]
  Brother MFC-1910W series = http://10.42.42.133:80/WebServices/ScannerService, WSD

If you have a similar output, this mean it's working, then you can use airscan-discover output to configure the detected scanner:

# airscan-discover | tee /etc/sane.d/home.conf

Now, your scanner should be usable!

3. Using the scanner §

You can run the command scanimage as a regular user to use your remote scanner, by default, it selects the first device available, so if you have a single scanner, you don't need to specify its long and complicated name/address.

You can scan and save as a PDF file using this command:

$ scanimage --format pdf > my_document.pdf

On Qubes OS, you can open a file manager in sys-net and right-click on the file to move it to the qube where you want to keep the document.

4. Disabling avahi §

If you are done with your scanner, you can remove the firewall rule allowing device discovery.

iptables -D INPUT -i INTERFACE_NAME -p udp --dport 5353 -j ACCEPT

5. Conclusion §

Using a network scanner is quite easy when it's supported by SANE, but you need direct access to the network because of the avahi discovery requirement, which is not practical when you have a firewall or use virtual machines in sub networks.

Old Computer Challenge v3: day 1

Written by Solène, on 10 July 2023.
Tags: #occ #oldcomputerchallenge

Comments on Fediverse/Mastodon

1. Day 1 §

Hi! Today, I started the 3rd edition of the Old Computer Challenge. And it's not going well, I didn't prepare a computer before, because I wanted to see how easy it would be.

Old Computer Challenge v3

  • main computer (Ryzen 5 5600X with 32 GB of memory) running Qubes OS: well, Qubes OS may be the worse OS for that challenge because it needs so much memory as everything is done in virtual machines, just handling USB devices requires 400 MB of memory
  • main laptop (a t470) running OpenBSD 7.3: for some reasons, the memory limitation isn't working, maybe it's due to the hardware or the 7.3 kernel
  • main laptop running OpenSUSE MicroOS (in dual boot): reducing the memory to 512MB prevent the system to unlock the LUKS drive!

The thing is that I have some other laptops around, but I'd have to prepare them with full disk encryption and file synchronization to have my passwords, GPG and SSH keys around.

With this challenge, in its first hour, I realized my current workflows don't allow me to use computers with 512 MB of memory, this is quite sad. A solution would be to use the iBook G4 laptop that I've been using since the beginning of the challenges, or my T400 running OpenBSD -current, but they have really old hardware, and the challenge is allowing some more fancy systems.

I'd really like to try Alpine Linux for this challenge, let's wrap something around this idea.

2. Extra / Tips §

If you joined the challenge, here is a previous guide to limit the memory of your system:

occ.deadnet.se: Tips & Tricks

For this challenge, you also need to use a single core at lowest frequency.

On OpenBSD, limiting the CPU frequency is easy:

  • stop obsdfreqd if you use it: rcctl stop obsdfreqd && rcctl disable obsdfreqd
  • rcctl enable apmd
  • rcctl set apmd flags -L
  • rcctl restart apmd

Still on OpenBSD, limiting your system to a single core can be done by booting on the bsd.sp kernel, which doesn't support multithreading.

How to install Kanboard on OpenBSD

Written by Solène, on 07 July 2023.
Tags: #openbsd #selfhosting #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

Let me share an installation guide on OpenBSD for a product I like: kanboard. It's a Kanban board written in PHP, it's easy of use, light, effective, the kind of software I like.

While there is a docker image for easy deployment on Linux, there is no guide to install it on OpenBSD. I did it successfuly, including httpd for the web server.

Kanboard official project website

2. Setup §

We will need a fairly simple stack:

  • httpd for the web server (I won't explain how to do TLS here)
  • php 8.2
  • database backed by sqlite, if you need postgresql or mysql, adapt

2.1. Kanboard files §

Prepare a directory where kanboard will be extracted, it must be owned by root:

install -d -o root -g wheel -m 755 /var/www/htdocs/kanboard

Download the latest version of kanboard, prefer the .tar.gz file because it won't require an extra program.

Kanboard GitHub releases

Extract the archive, and move the extracted content into /var/www/htdocs/kanboard; the file /var/www/htdocs/kanboard/cli should exists if you did it correctly.

Now, you need to fix the permissions for a single directory inside the project to allow the web server to write persistent data.

install -d -o www -g www -m 755 /var/www/htdocs/kanboard/data

2.2. PHP configuration §

For kanboard, we will need PHP and a few extensions. They can be installed and enabled using the following command: (for the future, 8.2 will be obsolete, adapt to the current PHP version)

pkg_add php-zip--%8.2 php-curl--%8.2 php-zip--%8.2 php-pdo_sqlite--%8.2
for mod in pdo_sqlite opcache gd zip curl
do
  ln -s /etc/php-8.2.sample/${mod}.ini /etc/php-8.2/
done
rcctl enable php82_fpm
rcctl start php82_fpm

Now you have the service php82_fpm (chrooted in /var/www/) ready to be used by httpd.

2.3. HTTPD configuration §

Configure the web server httpd, you can use nginx or apache if you prefer, with the following piece of configuration:

server "kanboard.my.domain" {
    listen on * port 80

    location "*.php" {
        fastcgi socket "/run/php-fpm.sock"
    } 

    # don't rewrite for assets (fonts, images)
    location "/assets/*" {
        root "/htdocs/kanboard/"
        pass
    }

    location match "/(.*)" {
        request rewrite "/index.php%1"
    }

    location "/*" {
        root "/htdocs/kanboard"
    }
}

Now, enable httpd if not already done, and (re)start httpd:

rcctl enable httpd
rcctl restart httpd

From now, Kanboard should be reachable and usable. The default credentials are admin/admin.

2.4. Sending emails §

If you want to send emails, you have three choices:

  • use php mail() which just use the local relay
  • use sendmail command, which will also use the local relay
  • configure an smtp server with authentication, can be a remote server

2.4.1. Local email §

If you want to use one of the first two methods, you will have to add a few files to the chroot like /bin/sh; you can find accurate and up to date information about the specific changes in the file /usr/local/share/doc/pkg-readms/php-8.2.

2.4.2. Using a remote smtp server §

If you want to use a remote server with authentication (I made a dedicated account for kanboard on my mail server):

Copy /var/www/htdocs/kanboard/config.default.php as /var/www/htdocs/kanboard/config.php, and changes the variables below accordingly:

define('MAIL_TRANSPORT', 'smtp');

define('MAIL_SMTP_HOSTNAME',   'my-server.local');
define('MAIL_SMTP_PORT',       587);
define('MAIL_SMTP_USERNAME',   'YOUR_SMTP_USER');
define('MAIL_SMTP_PASSWORD',   'XXXXXXXXXXXXXXXXXXXx');
define('MAIL_SMTP_HELO_NAME',  null);
define('MAIL_SMTP_ENCRYPTION', "tls");

Your kanboard should be able to send emails now. You can check by creating a new task, and click on "Send by email".

NOTE: Your user also NEED to enable email notifications.

2.5. Cronjob configuration §

For some tasks like reminding emails or stats computation, Kanboard requires to run a daily job by running a the CLI version.

You can do it as the www user in root crontab:

0 1 * * * -ns su -m www -c 'cd /var/www/htdocs/kanboard && /usr/local/bin/php-8.2 cli cronjob'

3. Conclusion §

Kanboard is a fine piece of software, I really like the kanban workflow to organize. I hope you'll enjoy it as well.

I'd also add that installing software without docker is still a thing, this requires you to know exactly what you need to make it run, and how to configure it, but I'd consider this a security bonus point. Think that it will also have all its dependencies updated along with your system upgrades over time.

Using anacron to run periodic tasks

Written by Solène, on 28 June 2023.
Tags: #openbsd #anacron

Comments on Fediverse/Mastodon

1. Introduction §

When you need to regularly run a program on your workstation that isn't powered 24/7 or even not every day, you can't rely on cronjob for that task.

Fortunately, there is a good old tool for this job (first release June 2000), it's called anacron and it will track when was the last time each configured tasks have been running.

I'll use OpenBSD as an example for the setup, but it's easily adaptable to any other Unix-like system.

Anacron official website

2. Installation §

The first step is to install the package anacron, this will provide the program /usr/local/sbin/anacron we will use later. You can also read OpenBSD specific setup instructions in /usr/local/share/doc/pkg-readmes/anacron.

Configure root's crontab to run anacron at system boot, we will use the flag -d to not run anacron as a daemon, and -s to run each task in a sequence instead of in parallel.

The crontab entry would look like this:

@reboot /usr/local/sbin/anacron -ds

If your computer is occasionally on for a few days, anacron won't run at all after the boot, so it would make sense to run it daily too just in case:

# at each boot
@reboot /usr/local/sbin/anacron -ds

# at 01h00 if the system is up
0 1 * * * /usr/local/sbin/anacron -ds

3. Anacron file format §

Now, you will configure the tasks you want to run, and at which frequency. This is configured in the file /etc/anacrontab using a specific format, different from crontab.

There is a man page named anacrontab for official reference.

The format consists of the following ordered fields:

  • the frequency in days at which the task should be started
  • the delay in minutes after which the task should be started
  • a readable name (used as an internal identifier)
  • the command to run

I said it before but it's really important to understand, the purpose of anacron is to run daily/weekly/monthly scripts on a system that isn't always on, where cron wouldn't be reliable.

Usually, anacron is started at the system boot and run each task from its anacrontab file, this is why a delay field is useful, you may not want your backup to start immediately upon reboot, while the system is still waiting to have a working network connection.

Some variables can be used like in crontab, the most important are PATH and MAILTO.

Anacron keeps the last run date of each task in the directory /var/spool/anacron/ using the identifier field as a filename, it will contain the last run date in the format YYYYMMDD.

4. Example for OpenBSD periodic maintenance §

I really like the example provided in the OpenBSD package. By default, OpenBSD has some periodic tasks to run every day, week and month at night, we can use anacron to run those maintenance scripts on our workstations.

Edit /etc/anacrontab with the following content:

SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
MAILTO=""

1  5 daily_maintenance    /bin/sh /etc/daily
7  5 weekly_maintenance   /bin/sh /etc/weekly
30 5 monthly_maintenance  /bin/sh /etc/monthly

You can manually run anacron if you want to check it's working instead of waiting for a reboot, just type doas anacron -ds.

What does the example mean?

  • every day, after 5 minutes (after anacron invokation) run /bin/sh /etc/daily
  • every 7 days, after 5 minutes, run /bin/sh /etc/weekly
  • every 30 days, after 5 minutes, run /bin/sh /etc/monthly

5. Useful examples §

Here is a list of tasks I think useful to run regularly on a workstation, that couldn't be handled by a cron job.

  • Backups: you may want to have a backup every day, or every few days
  • OpenBSD snapshot upgrade: use sysupgrade -ns every n days to download the sets, they will be installed at the next boot
  • OpenBSD packages update: use pkg_add -u every day
  • OpenBSD system update: use syspatch every day
  • Repositories update: keep your cloned git / fossil / cvs / svn repository up to date without doing it aggressively

6. Conclusion §

Anacron is a simple and effective way to keep your periodic tasks done even if you don't use your computer very often.

Ban scanners IPs from OpenSMTP logs

Written by Solène, on 22 June 2023.
Tags: #security #opensmtpd #openbsd #pf

Comments on Fediverse/Mastodon

1. Introduction §

If you are an OpenBSD running an OpenSMTP email server, you may want to ban IPs used by bots trying to bruteforce logins. OpenBSD doesn't have fail2ban available in packages, and sshguard isn't extensible enough to support the multiline log format used by OpenSMTP.

Here is a short script that looks for authentication failures in /var/mail/maillog and will add the IPs into the PF table bot after too many failed login.

2. Setup §

2.1. PF §

Add this rule to your PF configuration:

block in quick on egress from <bot> to any

This will block any connection from banned IPs, on all ports, not only smtp. I see no reason to allow them to try other doors.

2.2. Script §

Write the following content in an executable file, this could be /usr/local/bin/ban_smtpd but this doesn't really matter.

#!/bin/sh

TRIES=10
EXPIRE_DAYS=5

awk -v tries="$TRIES" '
	/ smtp connected / {
    		ips[$6]=substr($9, 9)
	}

	/ smtp authentication / && /result=permfail/ {
    		seen[ips[$6]]++
	}

	END {
    		for(ip in seen) {
        		if(seen[ip] > tries) {
            			print ip
    			}
		}
	}' /var/log/maillog | xargs pfctl -T add -t bot

# if the file exists, remove IPs listed there
if [ -f /etc/mail/ignore.txt ]
then
    cat /etc/mail/ignore.txt | xargs pfctl -T delete -t bot
fi

# remove IPs from the table after $EXPIRE_DAYS days
pfctl -t bot -T expire "$(( 60 * 60 * 24 * $EXPIRE_DAYS ))"

This parses the maillog file, so by default it has a rotation every day, you could adapt the script to your log rotation policy to match what you want, users failing with permfail are banned after some tries, configurable with $TRIES.

I added support for an ignore list, to avoid blocking yourself out, just add IP addresses in /etc/mail/ignore.txt.

Finally, banned IPs are unbanned after 5 days, you can change it using the variable EXPIRE_DAYS.

2.3. Cronjob §

Now, edit root's crontab, you want to run this script at least every hour, and get a log if it fails.

~ * * * * -sn /usr/local/bin/ban_smtpd

This cron job will run every hour at a random minute (defined each time crond restarts, so it stays consistent for a while). The periodicity may depend on the number of scan your email server receives and also the log size vs the CPU power.

3. Conclusion §

This would be better to have an integrated banning system supporting multiple logfiles / daemons, such as fail2ban, but in the current state it's not possible. This script is simple, fast, extensible and does the job.

Why one would use Qubes OS?

Written by Solène, on 17 June 2023.
Tags: #security #qubesos #feedback

Comments on Fediverse/Mastodon

1. Intro §

Hello, I've been talking a lot about Qubes OS lately but I never explained why I got hooked to its offer. It's time to tell why I like it.

Qubes OS official project website

Puffy asks Solene to babysit the girl. Solene presents her latest creation. (artwork by Prahou)
Puffy asks Solene to babysit the girl. Solene presents her latest creation. (artwork by Prahou)

Artwork by Prahou

2. Presentation §

Qubes OS is like a meta system emphasizing on security and privacy. You start on an almost empty XFCE interface on a system called dom0 (Xen hypervisor) with no network access: this is your desktop from which you will start virtual machines integrating into dom0 display in order to do what you need to do with your computer.

Virtual Machines in Qubes OS are called qubes, most of the time, you want them to be using a template (Debian or Fedora for the official ones). If you install a program in the template, it will be available in a Qube using that template. When a Qube is set to only have a persistent /home directory, it's called an AppVM. In that case, any change done outside /home will be discarded upon reboot.

By default, the system network devices are assigned to a special Qube named sys-net which is special in that it gets the physical network devices attached to the VM. sys-net purpose is to be disposable and provide network access to the outside to the VM named sys-firewall which will be doing some filtering.

All your qubes using Internet will have to use sys-firewall as their network provider. A practical use case if you want to use a VPN but not globally is to create a sys-vpn Qube (pick the name you want), connect it to the Internet using sys-firewall, and now you can use sys-vpn as the network source for qubes that should use your VPN, it's really effective.

If you need to use an USB device like a microphone and webcam in a Qube, you have a systray app to handle USB pass-through, from the special Qube sys-usb managing the physical USB controllers, to attach the USB device into a Qube. This allows you to plug anything USB into the computer, and if you need to analyze it, you can start a disposable VM and check what's in there.

Qubes OS trust level architecture diagram
Qubes OS trust level architecture diagram

2.1. Pros §

  • Efficient VM management due to the use of templates.
  • Efficient resource usage due to Xen (memory ballooning, para-virtualization).
  • Built for being secure.
  • Disposables VMs.
  • Builtin integration with Tor (using whonix).
  • Secure copy/paste between VMs.
  • Security (network is handled by a VM which gets the physical devices attached, hypervisor is not connected).
  • Practical approach: if you need to run a program you can't trust because you have too (this happens sometimes), you can do that in a disposable VM and not worry.
  • Easy update management + rollback ability in VMs.
  • Easy USB pass-through to VMs.
  • Easy file transfer between VMs.
  • Incredible VM windows integration into the host.
  • Qubes-rpc to setup things like split-ssh where the ssh key is stored in an offline VM, with user approval for each use.
  • Modular networking, I can make a VPN in a VPN and assign it to other VM but not all.
  • Easily extensible as all templates and VMs are managed by Salt Stack.

2.2. Cons §

  • No GPU acceleration for rendering (no 3D programs, high CPU usage for video/conferencing).
  • Limited hardware support due to Xen.
  • Requires a powerful system (high CPU requirement + the more RAM the better).
  • Qubes OS could be a choice by default because there is no competitor (yet).
  • The project seems a bit understaffed.
  • Hard learning curve.
  • Limited templates offer: Fedora, Debian and whonix are officials. The community provides extra templates based on Gentoo, Kali or Cent OS 8.
  • It's meant for a single person use only for a workstation.

3. My use case §

I tried Qubes OS early 2022, it felt very complicated and not efficient so I abandoned it only after a few hours. This year, I did want to try again for a longer time, reading documentation, trying to understand everything.

The more I used it, the more I got hooked by the idea, and how clean it was. I basically don't really want to use a different workflow anymore, that's why I'm currently implementing OpenKuBSD to have a similar experience on OpenBSD (even if I don't plan to have as many features as Qubes OS).

My workflow is the following, this doesn't mean it's the best one, but it fits my mindset and the way I want to separate things:

  • a Qube for web browsing with privacy plugins and Arkenfox user.js, this is what I use to browse websites in general
  • a Qube for communication: emails, XMPP and Matrix
  • a Qube for development which contains my projects source code
  • a Qube for each work client which contains their projects source code
  • an OpenBSD VM to do ports work (it's not as integrated as the other though)
  • a Qube without network for the KeePassXC databases (personal and per-client), SSH and GPG keys
  • a Qube using a VPN for some specific network tasks, it can be connected 24/7 without having all the programs going through the VPN (or without having to write complicated ip rules to use this route only in some case)
  • disposable VMs at hand to try things

I've configured my system to use split-SSH and split-GPG, so some qubes can request the use of my SSH key in the dom0 GUI, and I have to manually accept that one-time authorization on each use. It may appear annoying, but at least it gives me a visual indicator that the key is requested, from which VM, and it's not automatically approved (I only have to press Enter though).

I'm not afraid of mixing up client work with my personal projects due to different VM use. If I need to make experimentation, I can create a new Qube or use a disposable one, this won't affect my working systems. I always feel dirty and unsafe when I need to run a package manager like npm to build a program in a regular workstation...

Sometimes I want to experiment a new program, but I have no idea if it's safe when installing it manually or with "curl | sudo bash". In a dispoable, I just don't care, everything is destroyed when I close its terminal, and it doesn't contain any information.

What I really like is that when I say I'm using Qubes OS, for real I'm using Fedora, OpenBSD and NixOS in VMs, not "just" Qubes OS.

However, Qubes OS is super bad for multimedia in general. I have a dual boot with a regular Linux if I want to watch videos or use 3D programs (like Stellarium or Blender).

Qubes OS blog: how to organize your qubes: different users share their workflows

4. Why would you use Qubes OS? §

This is a question that seems to pop quite often on the project forum. It's hard to reply because Qubes OS has an important learning curve, it's picky with regard to hardware compatibility and requirements, and the pros/cons weight can differ greatly depending on your usage.

When you want important data to be kept almost physically separated from running programs, it's useful.

When you need to run programs you don't trust, it's useful.

When you prefer to separate contexts to avoid mixing up files / clipboard, like sharing some personal data in your workplace Slack, this can be useful.

When you want to use your computer without having to think about security and privacy, it's really not for you.

When you want to play video games, use 3D programs, benefit from GPU hardware acceleration (for machine learning, video encoding/decoding), this won't work, although with a second GPU you could attach it to a VM, but it requires some time and dedication to get it working fine.

5. Security §

Qubes OS security model relies on a virtualization software (currently XEN), however they are known to regularly have security issues. It can be debated whether virtualization is secure or not.

Qubes OS security advisory tracker

6. Conclusion §

I think Qubes OS has an unique offer with its compartmentalization paradigm. However, the required mindset and discipline to use it efficiently makes me warn that it's not for everyone, but more for a niche user base.

The security achieved here is relatively higher than in other systems if used correctly, but it really hinders the system usability for many common tasks. What I like most is that Qubes OS gives you the tools to easily solve practical problems like having to run proprietary and untrusted software.

Using git bundle to synchronize a repository between Qubes OS dom0 and an AppVM

Written by Solène, on 17 June 2023.
Tags: #security #qubesos #git

Comments on Fediverse/Mastodon

1. Introduction §

In a previous article, I explained how to use Fossil version control system to version the files you may write in dom0 and sync them against a remote repository.

I figured how to synchronize a git repository between an AppVM and dom0, then from the AppVM it can be synchronized remotely if you want. This can be done using the git feature named bundle, which bundle git artifacts into a single file.

Qubes OS project official website

Git bundle documentation

Using fossil to synchronize data from dom0 with a remote fossil repository

2. What you will learn §

In this setup, you will create a git repository (this could be a clone of a remote repository) in an AppVM called Dev, and you will clone it from there into dom0.

Then, you will learn how to send and receive changes between the AppVM repo and the one in dom0, using git bundle.

3. Setup §

The first step is to have git installed in your AppVM and in dom0.

For the sake of simplicity for the guide, the path /tmp/repo/ refers to the git repository location in both dom0 and the AppVM, don't forget to adapt to your setup.

In the AppVM Dev, create a git repository using cd /tmp/ && git init repo. We need a first commit for the setup to work because we can't bundle commits if there is nothing. So, commit at least one file in that repo, if you have no idea, you can write a short README.md file explaining what this repository is for.

In dom0, use the following command:

qvm-run -u user --pass-io Dev "cd /tmp/repo/ && git bundle create - master" > /tmp/git.bundle
cd /tmp/ && git clone -b master /tmp/git.bundle repo

Congratulations, you cloned the repository into dom0 using the bundle file, the path /tmp/git.bundle is important because it's automatically set as URL for the remote named "origin". If you want to manage multiple git repositories this way, you should use a different name for this exchange file for each repo.

[solene@dom0 repo]$ git remote -v
origin	/tmp/git.bundle (fetch)
origin	/tmp/git.bundle (push)

Back to the AppVM Dev, run the following command in the git repository, this will configure the bundle file to use for the remote dom0. Like previously, you can pick the name you prefer.

git remote add dom0 /tmp/dom0.bundle

4. Workflow §

Now, let's explain the workflow to exchange data between the AppVM and dom0. From here, we will only use dom0.

Create a file push.sh in your git repository with the content:

#!/bin/sh

REPO="/tmp/repo/"
BRANCH=master

# setup on the AppVM
# git remote add dom0 /tmp/dom0.bundle

git bundle create - origin/master..master | \
  qvm-run -u user --pass-io Dev "cat > /tmp/dom0.bundle"

qvm-run -u user --pass-io Dev "cd ${REPO} && git pull -r dom0 ${BRANCH}"

Create a file pull.sh in your git repository with the content:

#!/bin/sh

REPO="/tmp/repo/"
BRANCH=master

# init the repo on dom0
# git clone -b ${BRANCH} /tmp/git.bundle

qvm-run -u user --pass-io Dev "cd ${REPO} && git bundle create - dom0/master..${BRANCH}" > /tmp/git.bundle
git pull -r

Make the files push.sh and pull.sh executable.

If you don't want to have the files committed in your repository, add their names to the file .gitignore.

Now, you are able to send changes to the AppVM repo using ./push.sh, and receive changes using ./pull.sh.

If needed, those scripts could be made more generic and moved in a directory in your PATH instead of being used from within the git repository.

4.1. Explanations §

Here are some explanations about those two scripts.

4.1.1. Push.sh §

In the script push.sh, git bundle is used to send a bundle file over stdout containing artifacts from the remote AppVM last known commit up to the latest commit in the current repository, hence origin/master..master range. This data is piped into the file /tmp/dom0.bundle in the AppVm, and was configured earlier as a remote for the repository.

Then, the command git pull -r dom0 master is used to fetch the changes from the bundle, and rebase the current repository, exactly like you would do with a "real" remote over the network.

4.1.2. Pull.sh §

In the script pull.sh, we run the git bundle from within the AppVM Dev to generate on stdout the bundle from the last known state of dom0 up to the latest commit in the branch master, and pipe into the dom0 file /tmp/git.bundle, remember that this file is the remote origin in dom0's clone.

After the bundle creation, a regular git pull -r is used to fetch the changes, and rebase the repository.

4.1.3. Using branches §

If you use different branches, this could require adding an extra parameter to the script to make the variable BRANCH configurable.

5. Conclusion §

I find this setup really elegant, the safe qvm-run is used to exchange static data between dom0 and the AppVM, no network is involved in the process. Now there is no reason to have dom0 configuration file not properly tracked within a version control system :)

OpenKuBSD progress report

Written by Solène, on 16 June 2023.
Tags: #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

Here is a summary of my progress for writing OpenKuBSD. So far, I've had a few blockers but I've been able to find solutions, more or less simple and nice, but overall I'm really excited about how the project is turning out.

OpenKuBSD source code on tildegit.org (current branch == PoC)

As a quick introduction to OpenKuBSD in its current state, it's a program to install on top of OpenBSD, using mostly base system tools.

  • OpenBSD templates can be created and configured
  • Kubes (VMs) inherit an OpenBSD template for the disk, except for a dedicated persistent /home, any changes outside of /home will be reset on each boot
  • Kubes have a nice name like "www.kube" to connect to
  • NFS storage per Kube in /shared/ , this allows data to be shared with the host, which can then move files between Kubes via the shared directories
  • Xephyr based compartimentalization for GUI display. Each program run has its own Xephyr server.
  • Clipboard manipulation tool: a utility for copying the clipboard from one Xephyr to another one. This is a secure way to share the clipboard between Kubes without leakage.
  • On-demand start and polling for ssh connection, so you don't have to pre-start a Kube before running a program.
  • Executable /home/openkubsd/rc.local script at boot time to customize an environment at kube level rather than template level
  • Desktop entry integration: a script is available to create desktop entries to run program X on Kube Y, directly from the menu

The Xephyr trick was hard to figure and implement correctly. Originally, I used ssh -Y which worked fine, and integrated very well with the desktop however:

  • ssh -Y allows any window to access the X server, meaning any hacked VM could access all other running programs
  • ssh -X is secure, but super bad: slow, can't have a custom layout, crashes when trying to do access X in some cases. (fun fact, on Fedora, ForwardX11Trusted seems to be set to Yes by default, so ssh -X does ssh -Y!)
  • Xephyr worked, but running a program in it didn't use the full display, so a window manager was required. But all the tiling window managers I used (to automatically use all the screen) couldn't resize when Xephyr was resized.... except stumpwm!
  • Stumpwm custom configuration to quit when it has no more window displayed. If you exit your programs then stumpwm quits then Xephyr stops.

2. Demo videos §

OpenKuBSD: easily running programs from VMs

OpenKuBSD: NFS shares and desktop entries

OpenKuBSD: Xephyr implementation and clipboard helper

3. Roadmap §

I'm really getting satisfied with the current result. It's still far from being ready to ship or feature complete, but I think the foundations are quite cool.

Next steps:

  • tighten the network access for each Kube using PF (only NAT + host access + prevent spoofing)
  • allow a Kube to not have NAT (communication would be restricted to the host only for ssh access), this is the most "no network" implementation I can achieve.
  • allow a Kube to have a NAT from another Kube (to handle a Kube VPN for a specific list of Kubes)
  • figure how to make a Tor VPN Kube
  • allow to make disposable Kubes using the Tor VPN Kube network

Mid term steps:

  • support Alpine Linux (with features matching what OpenBSD Kubes have)

Long term steps:

  • rewrite all OpenKuBSD shell implementation into a daemon/client model, easier to install, more robust
  • define a configuration file format to declare all the infrastructure
  • release to wider audience
  • open a bug tracker

4. Conclusion §

The project is still in its beginning, but I made important progress over the last two weeks, I may reduce the pace here a bit to get everything stabilized. I started using OpenKuBSD on my own computer, this helps a lot to refine the workflow and see what feature matter, and which design is wrong or correct.

I hope you like that project as much as I do.

OpenKuBSD design document

Written by Solène, on 06 June 2023.
Tags: #openbsd #qubesos #security

Comments on Fediverse/Mastodon

1. Introduction §

I got an idea today (while taking a shower...) about _partially_ reusing Qubes OS design of using VMs to separate contexts and programs, but doing so on OpenBSD.

To make explanations CLEAR, I won't reimplement Qubes OS entirely on OpenBSD. Qubes OS is an interesting operating system with a very strong focus on security (from a very practical point of view ), but it's in my opinion overkill for most users, and hence not always practical or usable.

In the meantime, I think the core design could be reused and made it easy for users, like we are used to do in OpenBSD.

2. Why this project? §

I like the way Qubes OS allows to separate things and to easily run a program using a VPN without affecting the rest of the system. Using it requires a different mindset, one has to think about data silos, what do I need for which context?

However, I don't really like that Qubes OS has so many opened issues, governance isn't clear, and Xen seems to be creating a lot of troubles with regard to hardware compatibility.

I'm sure I can provide a similar but lighter experience, at the cost of "less" security. My threat model is more preventing data leak in case of a compromised system/software, than protecting my computer from a government secret agency.

After spending two months using "immutables" distributions (openSUSE MicroOS, Vanilla OS, Silverblue), where they all want to you use root-less containers (with podman) through distrobox, I hate that idea, it integrates poorly with the host, it's a nightmare to maintain, can create issues due to different versions of programs altering your user data directory, and that just doesn't bring anything much to the table except allowing users to install software without being root (and without having to reboot on those systems).

3. Key features §

Here is a list of features that I think good to implement.

  • vmd based OpenBSD and Alpine template (installation automated), with the help of qcow2 format for VMs, it's possible to create a disk based on another, a must for using templates
  • disposable VMs, they are started from the template but using a derived disk of the template, destroyed after use
  • AppVM, a VM created with a persistent /home, and the rest of the system is inherited from the template using a derived qcow2 from template
  • VPN VMs that could be used by other VMs as their network source (Tor VPN template should be provided)
  • Simple configuration file describing your templates, your VMS, packages installed (in templates), and which network source to use for which VM
  • Installing software in templates will create .desktop files in menus to easily start programs (over ssh -Y)
  • OpenBSD host should be USABLE (hardware acceleration, network handling, no perf issues)
  • OpenBSD host should be able to transfer files between VMs using ssh
  • Audio disabled by default on VMs, sndio could be allowed (by the user in a configuration file) to send the sound to the host
  • Should work with at least 4 GB of memory (I would like to make just 2 as a requirement if possible)

Some kind of quick diagram explaining relationship of various components. This doesn't show the whole picture because it wouldn't be easy to represent (and I didn't had time to try doing so yet):

OpenKuBSD design diagram
OpenKuBSD design diagram

4. What I don't plan to do §

  • HVM support and passthrough, this could be done one day if vmd supports passthrough, but this creates too much problems, and only help security for niche use case I don't want to focus on
  • USB passthrough, too complex to implement, too niche use case
  • VM RPC, except for the host being able to copy files from one vm to the other using ssh
  • An OpenBSD distribution, OpenKuBSD must be installable on top of OpenBSD with the least friction possible, not as a separate system
  • Support Windows guests

5. Roadmap §

The first step is to make a proof of concept:

  • generate the OpenBSD template automatically
  • being able to start a disposable VM using the OpenBSD template
  • generate an OpenBSD Tor template
  • being able to use it in the disposable VM

6. Trivia §

I announced it as OpenKuBISD, but I prefer to name it OpenKuBSD :)

The Old Computer Challenge V3

Written by Solène, on 04 June 2023.
Tags: #life #oldcomputerchallenge #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

Hi! It's that time of the year when I announce a new Old Computer Challenge :)

If you don't know about it, it's a weird challenge I've did twice in the past 3 years that consists into limiting my computer performance using old hardware, or by limiting Internet access to 60 minutes a day.

Blog posts tagged "oldcomputerchallenge"

2. 2023's challenge §

I want this challenge to be accessible. The first one wasn't easy for many because it required to use an old machine, but many readers didn't have a spare old computer (weird right? :P). The second one with Internet time limitation was hard to setup.

This one is a bit back to the roots: let's use a SLOW computer for 7 days. This will be achieved by various means with any hardware:

  • Limit your computer's CPU to use only 1 core. This can be set in the BIOS most of the time, and on Linux you can use maxcores=1 in the boot command line, on OpenBSD you can use bsd.sp kernel for the duration of the challenge.
  • Limit your computer's memory to 512 MB of memory (no swap limit). This can be set on Linux using the boot command line mem=512MB. On OpenBSD, this can be achieved a bit similarly by using datasize-max=512M in login.conf for your user's login class.
  • Set your CPU frequency to the lowest minimum (which is pretty low on modern hardware!). On Linux, use the "powersave" frequency governor, in modern desktop environments the battery widget should offer an easy way to set the governor. On OpenBSD, run apm -L (while apmd service is running). On Windows, in the power settings, set the frequency to minimum.

I got the idea when I remembered a few people reporting these tricks to do the first challenge, like in this report:

Carcosa's report of the first challenge (link via gemini http bridge)

You are encouraged to join the IRC channel #oldcomputerchallenge on libera.chat server to share about your experience.

Feel free to write reports, it's always fun to read about other going through the challenge.

3. When §

The challenge will start the 10th July 2023, and end the 16th July 2023 at the end of the day.

4. Frequently asked questions §

  • If you use a computer to work, it isn't affected by the challenge, keep your job please. But don't use it to circumvent your regular slow computer.
  • If you use a computer with lower specs, this is compliant with the challenge rules.
  • Feel free to ask me questions, I want this to be easy to everyone to have fun together. I can update this blog post to make things clearer if needed.
  • Gnome desktop doesn't start with 512 MB of memory :D

Qubes OS dom0 files workflow using fossil

Written by Solène, on 04 June 2023.
Tags: #qubesos #fossil

Comments on Fediverse/Mastodon

1. Introduction §

Since I'm using Qubes OS, I always faced an issue; I need a proper tracking of the configuration files for my systemthis can be done using Salt as I explained in a previous blog post. But what I really want is a version control system allowing me to synchronize changes to a remote repository (it's absurd to backup dom0 for every change I make to a salt file). So far, git is too complicated to achieve that.

I gave a try with fossil, a tool I like (I wrote about this one too ;) ), and it was surprisingly easy to setup remote access leveraging Qubes'qvm-run.

In this blog post, you will learn how to setup a remote fossil repository, and how to use it from your dom0.

Previous article about Fossil cheatsheet

2. Repository creation §

On the remote system where you want to store the fossil repository (it's a single file), run fossil init my-repo.fossil.

The only requirement for this remote system is to be reachable over SSH by an AppVM in your Qubes OS.

3. dom0 clone §

Now, we will clone this remote repository in our dom0, I'm personnally fine with storing such files in /root/ directory.

In the following example, the file my-repo.fossil was created on the machine 10.42.42.200 with the path /home/solene/devel/my-repo.fossil. I'm using the AppVM qubes-devel to connect to the remote host using SSH.

[root@dom0 ~#] fossil clone --ssh-command "qvm-run --pass-io --no-gui -u user qubes-devel 'ssh'" ssh://10.42.42.200://home/solene/devel/my-repo.fossil /root/my-repo.fossil

This command clone a remote fossil repository by piping the SSH command through qubes-devel AppVM, allowing fossil to reach the remote host.

Cool fact with fossil's clone command, it keeps the proxy settings, so no further changes are required.

With a Split SSH setup, I'm asked everytime fossil is synchronizing; by default fossil has "autosync" mode enabled, for every commit done the database is synced with the remote repository.

4. Open the repository (reminder about fossil usage) §

As I said, fossil works with repository files. Now you cloned the repository in /root/my-repo.fossil, you could for instance open it in /srv/ to manage all your custom changes to the dom0 salt.

This can be achieved with the following command:

[root@dom0 ~#] cd /srv/
[root@dom0 ~#] fossil open --force /root/my-repo.fossil

The --force flag is needed because we need to open the repository in a non-empty directory.

5. Conclusion §

Finally, I figured a proper way to manage my dom0 files, and my whole host. I'm very happy of this easy and reliable setup, especially since I'm already a fossil user. I don't really enjoy git, so demonstrating alternatives working fine always feel great.

If you want to use Git, I have a hunch that something could be done using git bundle, but this requires some investigation.

Install OpenBSD in Qubes OS

Written by Solène, on 03 June 2023.
Tags: #qubesos #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Here is a short guide explaining how to install OpenBSD in Qubes OS, as an HVM VM (fully virtualized, not integrated).

2. Get OpenBSD §

Download an ISO file to install OpenBSD, do it from an AppVM. You can use the command cksum -a sha256 install73.iso in the AppVM to generate a checksum to compare with the file SHA256 to be found in the OpenBSD mirror.

3. Create a Qube §

In the XFCE menu > Qubes Tools > Create Qubes VM GUI, choose a name, use the type "StandaloneVM (fully persistent)", use "none" as a template and check "Launch settings after creation".

4. Configuration §

In the "Basic" tab, configure the "system storage max size", that's the storage size OpenBSD will see at installation time. OpenBSD storage management is pretty limited, if you add more space later it will be complicated to grow partitions, so pick something large enough for your task.

Still in the "Basic" tab, you have all the network information, keep them later (you can open the Qube settings after the VM booted) to configure your OpenBSD.

In "Firewall rules" tab, you can set ... firewall rules that happens at Qubes OS level (in the sys-firewall VM).

In the "Devices" tab, you can expose some internal devices to the VM (this is useful for networking VMs).

In the "Advanced" tab, choose the memory to use and the number of CPU. In the "Virtualization" square, choose the mode "HVM" (it should already be selected). Finally, click on "Boot qube from CD-ROM" and pick the downloaded file by choosing the AppVM where it is stored and its path. The VM will directly boot when you validate.

5. Installation §

The installation process is straightforward, here is the list (in order of appearance) of questions that require a specific answer:

  • choose network device xnf0 to configure
  • set the IPv4 address given in the Qube network information
  • set the netmask to 255.0.0.0
  • there is no IPv6 (well, it's possible in Qube but I let you have fun)
  • Default IPv4 route is given in the Qube network information
  • DNS nameservers are the two addresses in the Qube network information
  • Use the disk sd0
  • Format the disk using MBR (Xen doesn't support UEFI it seems)
  • Sets are located in cd0

Whether you reboot or halt the VM, it will be halted, so start it again.

6. Enjoy §

You should get into your working OpenBSD VM with functional network.

Be careful, it doesn't have any specific integration with Qubes OS like the clipboard, USB passthrough etc... However, it's a HVM system, so you could give it an USB controller or a dedicated GPU.

7. Conclusion §

It's perfectly possible to run OpenBSD in Qube OS with very decent performance, the setup is straightforward when you know where to look for the network information (and that the netmask is /8 and not /32 like on Linux).

Declaratively manage your Qubes OS

Written by Solène, on 02 June 2023.
Tags: #qubesos #salt #qubes

Comments on Fediverse/Mastodon

1. Introduction §

As a recent Qubes OS user, but also a NixOS user, I want to be able to reproduce my system configuration instead of fiddling with files everywhere by hand and being clueless about what I changed since the installation time.

Fortunately, Qubes OS is managed internally with Salt Stack (it's similar to Ansible if you didn't know about Salt), so we can leverage salt to modify dom0 or Qubes templates/VMs.

Qubes OS official project website

Salt Stack project website

Qubes OS documentation: Salt

2. Simple setup §

In this example, I'll show how to write a simple Salt state files, allowing you to create/modify system files, install packages, add repositories etc...

Everything will happen in dom0, you may want to install your favorite text editor in it. Note that I'm still trying to figure a nice way to have a git repository to handle this configuration, and being able to synchronize it somewhere, but I still can't find a solution I like.

The dom0 salt configuration can be found in /srv/salt/, this is where we will write:

  • a .top file that is used to associate state files to apply to which hosts
  • a state file that contain actual instructions to run

Quick extra explanation: there is a directory /srv/pillar/, where you store things named "pillars", see them as metadata you can associate to remote hosts (AppVM / Templates in the Qubes OS case). We won't use pillars in this guide, but if you want to write more advanced configurations, you will surely need them.

3. dom0 management §

Let's use dom0 to manage itself 🙃.

Create a text file /srv/salt/custom.top with the content (YAML format):

base:
  'dom0':
    - dom0

This tells that hosts matching dom0 (2nd line) will use the state named dom0.

We need to enable that .top file so it will be included when salt is applying the configuration.

qubesctl top.enable custom

Now, create the file /srv/salt/dom0.sls with the content (YAML format):

my packages:
  pkg.installed:
    - pkgs:
      - kakoune
      - git

This uses the salt module named pkg, and pass it options in order to install the packages "git" and "kakoune".

Salt Stack documentation about the pkg module

On my computer, I added the following piece of configuration to /srv/salt/dom0.sls to automatically assign the USB mouse to dom0 instead of being asked every time, this implements the instructions explained in the documentation link below:

Qubes OS documentation: USB mice

/etc/qubes-rpc/policy/qubes.InputMouse:
  file.line:
    - mode: ensure
    - content: "sys-usb dom0 allow"
    - before: "^sys-usb dom0 ask"

Salt Stack documentation: file line

This snippet makes sure that the line sys-usb dom0 allow in the file /etc/qubes-rpc/policy/qubes.InputMouse is present above the line matching ^sys-usb dom0 ask. This is a more reproducible way of adding lines to configuration file than editing by hand.

Now, we need to apply the changes by running salt on dom0:

qubesctl --target dom0 state.apply

You will obtain a list of operations done by salt, with a diff for each task, it will be easy to know if something changed.

Note: state.apply used to be named state.highstate (for people who used salt a while ago, don't be confused, it's the same thing).

4. Template management §

Using the same method as above, we will add a match for the fedora templates in the custom top file:

In /srv/salt/custom.top add:

  'fedora-*':
    - globbing: true
    - fedora

This example is slightly different than the one for dom0 where we matched the host named "dom0". As I want my salt files to require the least maintenance possible, I won't write the template name verbatim, but I'd rather use a globbing (this is the name for simpler wildcard like foo*) matching everything starting by fedora-, I currently have fedora-37 and fedora-38 on my computer, so they are both matching.

Create /srv/salt/fedora.sls:

custom packages:
  pkg.installed:
    - pkgs:
      - borgbackup
      - dino
      - evolution
      - fossil
      - git
      - pavucontrol
      - rsync
      - sbcl
      - tig

In order to apply, we can type qubesctl --all state.apply, this will work but it's slow as salt will look for changes in each VM / template (but we only added changes for fedora templates here, so nothing would change except for the fedora templates).

For a faster feedback loop, we can specify one or multiple targets, for me it would be qubesctl --targets fedora-37,fedora-38 state.apply, but it's really a matter of me being impatient.

5. Auto configure Split SSH §

An interesting setup with Qubes OS is to have your SSH key in a separate VM, and use Qubes OS internal RPC to use the SSH from another VM, with a manual confirmation on each use. However, this setup requires modifying files at multiple places, let's see how to manage everything with salt.

Qubes OS community documentation: Split SSH

Reusing the file /srv/salt/custom.top created earlier, we add split_ssh_client.sls for some AppVMs that will use the split SSH setup. Note that you should not deploy this state to your Vault, it would self reference for SSH and would prevent the agent to start (been there :P):

base:
  'dom0':
    - dom0
  'fedora-*':
    - globbing: true
    - fedora
  'MyDevAppVm or MyWebBrowserAppVM':
    - split_ssh_client

Create /srv/salt/split_ssh_client.sls: this will add two files to load the environment variables from /rw/config/rc.local and ~/.bashrc. It's actually easier to separate the bash snippets in separate files and use source, rather than using salt to insert the snippets directly in place where needed.

/rw/config/bashrc_ssh_agent:
  file.managed:
    - user: root
    - group: wheel
    - mode: 444
    - contents: |
        SSH_VAULT_VM="vault"
        if [ "$SSH_VAULT_VM" != "" ]; then
          export SSH_AUTH_SOCK="/home/user/.SSH_AGENT_$SSH_VAULT_VM"
        fi

/rw/config/rclocal_ssh_agent:
  file.managed:
    - user: root
    - group: wheel
    - mode: 444
    - contents: |
        SSH_VAULT_VM="vault"
        if [ "$SSH_VAULT_VM" != "" ]; then
          export SSH_SOCK="/home/user/.SSH_AGENT_$SSH_VAULT_VM"
          rm -f "$SSH_SOCK"
          sudo -u user /bin/sh -c "umask 177 && exec socat 'UNIX-LISTEN:$SSH_SOCK,fork' 'EXEC:qrexec-client-vm $SSH_VAULT_VM qubes.SshAgent'" &
        fi

/rw/config/rc.local:
  file.append:
    - text: source /rw/config/rclocal_ssh_agent

/rw/home/user/.bashrc:
  file.append:
    - text: source /rw/config/bashrc_ssh_agent

Edit /srv/salt/dom0.sls to add the SshAgent RPC policy:

/etc/qubes-rpc/policy/qubes.SshAgent:
  file.managed:
    - user: root
    - group: wheel
    - mode: 444
    - contents: |
        MyClientSSH vault ask,default_target=vault

Now, run qubesctl --all state.apply to configure all your VMs, which are the template, dom0 and the matching AppVMs. If everything went well, you shouldn't have errors when running the command.

6. Use a dedicated AppVM for web browsing §

Another real world example, using Salt to configure your AppVMs to open links in a dedicated AppVM (named WWW for me):

Qubes OS Community Documentation: Opening URLs in VMs

In your custom top file /srv/salt/custom.top, you need something similar to this (please adapt if you already have top files or state files):

  'dom0':
    - dom0
  'fedora-*':
     - globbing: true
     - fedora
  'vault or qubes-communication or qubes-devel':
    - default_www

Add the following text to /srv/salt/dom0.sls, this is used to configure the RPC:

/etc/qubes-rpc/policy/qubes.OpenURL:
  file.managed:
    - user: root
    - group: wheel
    - mode: 444
    - contents: |
        @anyvm @anyvm ask,default_target=WWW

Add this to /srv/salt/fedora.sls to create the desktop file in the template:

/usr/share/applications/browser_vm.desktop:
  file.managed:
    - user: root
    - group: wheel
    - mode: 444
    - contents: |
        [Desktop Entry]
        Encoding=UTF-8
        Name=BrowserVM
        Exec=qvm-open-in-vm browser %u
        Terminal=false
        X-MultipleArgs=false
        Type=Application
        Categories=Network;WebBrowser;
        MimeType=x-scheme-handler/unknown;x-scheme-handler/about;text/html;text/xml;application/xhtml+xml;application/xml;application/rss+xml;x-scheme-handler/http;x-scheme-handler/https;

Create /srv/salt/default_www.sls with the following content, this will run xdg-settings to set the default browser:

xdg-settings set default-web-browser browser_vm.desktop:
  cmd.run:
    - runas: user

Now, run qubesctl --target fedora-38,dom0 state.apply.

From there, you MUST reboot the VMs that will be configured to use the WWW AppVm as the default browser, they need to have the new file browser_vm.desktop available for xdg-settings to succeed. Run qubesctl --target vault,qubes-communication,qubes-devel state.apply.

Congratulations, now you will have a RPC prompt when an AppVM wants to open a file to ask you if you want to open it in your browsing AppVM.

7. Conclusion §

This method is a powerful way to handle your hosts, and it's ready to use on Qubes OS. Unfortunately, I still need to figure a nicer way to export the custom files written in /srv/salt/ and track the changes properly in a version control system.

Erratum: I found a solution to manage the files :-) stay tuned for the next article.

Backport OpenBSD 7.3 pkg_add enhancement

Written by Solène, on 30 May 2023.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Recently, OpenBSD package manager received a huge speed boost when updating packages, but it's currently only working in -current due to an issue.

Fortunately, espie@ fixed it for the next release, I tried it and it's safe to fix yourself. It will be available in the 7.4 release, but for 7.3 users, here is how to apply the change.

Link to the commit (GitHub)

2. Fix §

There is a single file modified, just download the patch and apply it on /usr/libdata/perl5/OpenBSD/PackageRepository/Installed.pm with the command patch.

cd /usr/libdata/perl5/OpenBSD/PackageRepository/
ftp -o /tmp/pkg_add.patch https://github.com/openbsd/src/commit/fa222ab7fc13c118c838e0a7aaafd11e2e4fe53b.patch
patch -C < /tmp/pkg_add.patch && patch < /tmp/pkg_add.patch && rm /tmp/pkg_add.patch

After that, running pkg_add -u should be at least 5 or 10 times faster, and will use a lot less bandwidth.

3. Some explanations §

On -current, there is a single directory to look for packages, but on release for architectures amd64, aarch64, sparc64 and i386, there are two directories: the packages generated for the release, and the packages-stable directory receiving updates during the release lifetime.

The code wasn't working with the two paths case, preventing pkg_add to build a local packages signature to compare the remote signature database in the "quirks" package in order to look for updates. The old behavior was still used, making pkg_add fetching the first dozen kilobytes of each installed packages to compare their signature package by package, while now everything is stored in quirks.

4. Disclaimer §

If you have any issue, just revert the patch by adding -R to the patch command, and report the problem TO ME only.

This change is not officially supported for 7.3, so you are on your own if there is an issue, but it's not harmful to do. If you were to have an issue, reporting it to me would help solving it for 7.4 for everyone, but really, it just work without being harmful in the worse case scenario.

5. Conclusion §

I hope you will enjoy this change so you don't have to wait for 7.4. This makes OpenBSD pkg_add feeling a bit more modern, compared to some packages manager that are now almost instant to install/update packages.

Send XMPP messages from the command line

Written by Solène, on 25 May 2023.
Tags: #xmpp #monitoring #selfhosting #reed-alert

Comments on Fediverse/Mastodon

1. Introduction §

As a reed-alert user for monitoring my servers, while using emails works efficiently, I wanted to have more instant notifications for critical issues. I'm also an happy XMPP user, so I looked for a solution to send XMPP messages from a command line.

More about reed-alert on the blog

Reed-alert project git repository

I will explain how to use the program go-sendxmpp to send messages from a command line, this is a newer drop-in replacement for the old perl sendxmpp that doesn't seem to work anymore.

go-sendxmpp project git repository

2. Installation §

Following go-sendxmpp documentation, you need go to be installed, and then run go install salsa.debian.org/mdosch/go-sendxmpp@latest to compile the binary in ~/go/bin/go-sendxmpp. Because it's a static binary, you can move it to a directory in $PATH.

If I'm satisfied of it, I'll import go-sendxmpp into the OpenBSD ports tree to make it available as a package for everyone.

3. Configuration §

Open a shell with the user that is going to run go-sendxmpp, prepare the configuration file in its default location:

mkdir -p ~/.config/go-sendxmpp
touch ~/.config/go-sendxmpp/config
chmod 400 ~/.config/go-sendxmpp/config

Edit the file ~/.config/go-sendxmpp/config to add the two lines:

username: myuser@myserver
password: hunter2_oryourpassword

Now, your user should be ready to use go-sendxmpp, I recommend always enabling the flag -t to use TLS to connect to the server, but you should really choose an XMPP server providing TLS-only.

The program usage is simple: echo "this is a message for you" | go-sendxmpp dest@remote, and you are done. It's easy to integrate it in shell tasks.

Note that go-sendxmpp allows you to get the password for a command instead of storing it in plain text, this may be more convenient and secure in some scenarios.

4. Reed-alert configuration §

Back to reed-alert, using go-sendxmpp is as easy as declaring a new alert type, especially using the email template:

(alert xmpp "echo -n '[%state%] Problem with %function% %date% %params%' | go-sendxmpp user@remote")

;; example of use
(=> xmpp ping :host "dataswamp.org" :desc "Ping to dataswamp.org")

5. Conclusion §

XMPP is a very reliable communication protocol, I'm happy that I found go-sendxmpp, a modern, working and simple way to programmatically send me alerts using XMPP.

How to install Nix in a Qubes OS AppVM

Written by Solène, on 15 May 2023.
Tags: #qubes #qubesos #nix #nixos

Comments on Fediverse/Mastodon

1. Intro §

I'm still playing with Qubes OS, today I had to figure how to install Nix because I rely on it for some tasks. It turned out to be a rather difficult task for a Qubes beginner like me when not using a fully persistent VM.

Here is how to install Nix in an AppVm (only /home/ is persistent) and some links to the documentation about bind-dirs, an important component of Qubes OS that I didn't know about.

Qubes OS documentation: How to make any file persistent (bind-dirs)

Nix project website

2. bind-dirs §

Behind this unfriendly name is a smart framework to customize templates or AppVM. It allows running commands upon VM start, but also make directories explicitly persistent.

The configuration can be done at the local or template level, in our case, we want to create /nix and make it persistent in a single VM, so that when we install nix packages, they will be stay after a reboot.

The implementation is rather simple, the persistent directory is under the /rw partition in ext4, which allows mounting subdirectories. So, if the script finds /rw/bind-dirs/nix it will mount this directory on /nix on the root filesystem, making it persistent and without having to copy at start and sync on stop.

3. Setup §

A limitation for this setup is that we need to install nix in single user mode, without the daemon. I suppose it should be possible to install Nix with the daemon, but it should be done at the template level as it requires adding users, groups and systemd units (service and socket).

In your AppVM, run the following commands as root:

mkdir -p /rw/config/qubes-bind-dirs.d/
echo "binds+=( '/nix' )" > /rw/config/qubes-bind-dirs.d/50_user.conf
install -d -o user -g user /rw/bind-dirs/nix

This creates an empty directory nix owned by the regular Qubes user named user, and we tell bind-dirs that this directory is persistent.

/!\ It's not clear if it's a bug or a documentation issue, but the creation of /rw/bind-dirs/nix wasn't obvious. Someone already filled a bug about this, and funny enough, they reported it using Nix installation as an example.

GitHub issue: clarify bind-dirs documentation

Now, reboot your VM, you should have a /nix directory that is owned by your user. This mean it's persistent, and you can confirm that by looking at mount | grep /nix output which should have a line.

Finally, install nix in single user mode, using the official method:

sh <(curl -L https://nixos.org/nix/install) --no-daemon

Now, we need to fix the bash code to load Nix into your environment. The installer modified ~/.bash_profile, but it isn't used when you start a terminal from dom0, it's only used when using a full shell login with bash -l, which doesn't happen on Qubes OS.

Copy the last line of ~/.bash_profile in ~/.bashrc, this should look like that:

if [ -e /home/user/.nix-profile/etc/profile.d/nix.sh ]; then . /home/user/.nix-profile/etc/profile.d/nix.sh; fi # added by Nix installer

Now, open a new shell, you have a working Nix in your environment \o/

You can try it using nix-shell -p hello and run hello. If you reboot, the same command should work immediately without need to download packages again.

4. Configuration §

In your Qube settings, you should increase the disk space for the "Private storage" which is 2 GB by default.

5. Conclusion §

Installing Nix in a Qubes OS AppVM is really easy, but you need to know about some advanced features like bind-dirs. This is a powerful feature that will allow me to make lot of fun stuff with Qubes now, and using nix is one of them!

6. Going further §

If you plan to use Nix like this in multiple AppVM, you may want to set up a local substituter cache in a dedicated VM, this will make your bandwidth usage a lot more efficient.

How to make a local NixOS cache server

Create a custom application entry in Qubes OS

Written by Solène, on 14 May 2023.
Tags: #qubes #qubesos #freedesktop

Comments on Fediverse/Mastodon

1. Introduction §

If you use Qubes OS, you already know that installed software in templates are available in your XFCE menu for each VM, and can be customized from the Qubes Settings panel.

Qubes OS documentation about How to install software

However, if you want to locally install a software, either by compiling it, or using a tarball, you won't have a application entry in the Qubes Settings, and running this program from dom0 will require using an extra terminal in the VM. But we can actually add the icon/shortcut by creating a file at the right place.

In this example, I'll explain how I made a menu entry for the program DeltaChat, "installed" by downloading an archive containing the binary.

2. Desktop files §

In the VM (with a non-volatile /home) create the file /home/user/.local/share/applications/deltachat.desktop, or in a TemplateVM (if you need to provide this to multiple VMs) in the path /usr/share/applications/deltachat.desktop:

[Desktop Entry]
Encoding=UTF-8
Version=1.0
Type=Application
Terminal=False
Exec=/home/user/Downloads/deltachat-desktop-1.36.4/deltachat-desktop
Name=DeltaChat

This will create a desktop entry for the program named DeltaChat, with the path to the executable and a few other information. You can add an Icon= attribute with a link toward an image file, I didn't have one for DeltaChat.

3. Qubes OS integration §

With the .desktop file created, open the Qubes settings and refresh the applications list, you should find an entry with the Name you used. Voilà!

4. Conclusion §

Knowing how to create desktop entries is useful, not even on Qubes OS but for general Linux/BSD use. Being able to install custom programs with a launcher in Qubes dom0 is better than starting yet another terminal to run a GUI program from there.

5. Going further §

If you want to read more about the .desktop files specifications, you can read the links below:

Desktop entry specifications

Arch Linux wiki about Desktop entries

Making Qubes OS backups more efficient

Written by Solène, on 12 May 2023.
Tags: #qubes #qubesos #backup

Comments on Fediverse/Mastodon

1. Introduction §

These days, I've been playing a lot with Qubes OS, it has an interesting concept of deploying VMs (using Xen) in a well integrated and transparent manner in order to hardly separate every tasks you need.

By default, you get default environments such as Personal, Work and an offline Vault, plus specials VMs to handle USB proxy, network and firewall. What is cool here is that when you run a program from a VM, only the window is displayed in your window manager (xfce), and not the whole VM desktop.

The cool factor with this project is their take on the real world privacy and security need, allowing users to run what they need to run (proprietary software, random binaries), but still protect them. Its goal is totally different from OpenBSD and Tails. Did I say you can also route a VM network through Tor out of the box? =D

If you want to learn more, you can visit Qubes OS website (or ask if you want me to write about it):

Qubes OS official website

New user guide: How to organize your cubes (nice reading to understand Qubes OS)

2. Backups §

If you know me, you should know I'm really serious about backups. This is incredibly important to have backups.

Qubes OS has a backup tool that can be used out of the box, it just dump the VMs storage into an encrypted file, it's easy but not efficient or practical enough for me.

If you want to learn more about the format used by Qubes OS (and how to open them outside of Qubes OS), they wrote some documentation:

Qubes OS: backup emergency restore

Now, let's see how to store the backups in Restic or Borg in order to have proper backups.

/!\ While both software support deduplication, this doesn't work well in this case because the stored data are compressed + encrypted already, which has a very high entropy (it's hard to find duplicated patterns).

3. Backup tool §

Qubes OS backup tool offers compression and encryption out of the box, but when it comes to the storage location, we can actually use a command to send the backups to the command's stdin, and guess what, both restic and borg support receiving data on their standard input!

I'll demonstrate how to proceed both with restic and borg with a simple example, I recommend to build your own solution on top of it the way you need.

Screenshot of Qubes backup tool
Screenshot of Qubes backup tool

4. Create a backup VM §

As we are running Qubes OS, I prefer to create a dedicated backup VM using the Fedora template, it will contain the passphrase to the repository and an SSH key for remote backup.

You need to install restic/borg in the template to make it available in that VM.

If you don't know how to install software in a template, it's well documented:

Qubes OS: how to install software

Generate an SSH key if you want to store your data on a remote server using SSH, and deploy it on the remote server.

5. Write a backup script §

In order to simplify the backup command configuration in the backup tool (it's a single input line), but don't sacrifice on features like pruning, we will write a script on the backup VM doing everything we need.

While I'm using a remote repository in the example, nothing prevents you from using a local/external drive for your backups!

The script usage will be simple enough for most tasks:

  • ./script init to create the repository
  • ./script backup to create the backup
  • ./script list to display snapshots
  • ./script restore $snapshotID to restore a backup, the output file will always be named stdin

5.1. Restic §

Write a script in /home/user/restic.sh in the backup VM, it will allow simple customization of the backup process.

#!/bin/sh

export RESTIC_PASSWORD=mysecretpass

# double // is important to make the path absolute
export RESTIC_REPOSITORY=sftp://solene@10.42.42.150://var/backups/restic_qubes

KEEP_HOURLY=1
KEEP_DAYS=5
KEEP_WEEKS=1
KEEP_MONTHS=1
KEEP_YEARS=0


case "$1" in
    init)
        restic init
        ;;
    list)
    	restic snapshots
    	;;
    restore)
    	restic restore --target . $2
    	;;
    backup)
        cat | restic backup --stdin
        restic forget \
        	--keep-hourly $KEEP_HOURLY \
        	--keep-daily $KEEP_DAYS \
        	--keep-weekly $KEEP_WEEKS \
        	--keep-monthly $KEEP_MONTHS \
        	--keep-yearly $KEEP_YEARS \
        	--prune
        ;;
esac

Obviously, you have to change the password, you can even store it in another file and use the according restic option to load the passphrase from a file (or from a command). Although, Qubes OS backup tool enforces you to encrypt the backup (which will be store in restic), so encrypting the restic repository won't add any more security, but it can add privacy by hiding what's in the repo.

/!\ You need to run the script with the parameter "init" the first time, in order to create the repository:

$ chmod +x restic.sh
$ ./restic.sh init

5.2. Borg §

Write a script in /home/user/borg.sh in the backup VM, it will allow simple customisation of the backup process.

#!/bin/sh

export BORG_PASSPHRASE=mysecretpass
export BORG_REPO=ssh://solene@10.42.42.150/var/solene/borg_qubes

KEEP_HOURLY=1
KEEP_DAYS=5
KEEP_WEEKS=1
KEEP_MONTHS=1
KEEP_YEARS=0

case "$1" in
    init)
        borg init --encryption=repokey
        ;;
    list)
    	borg list
    	;;
    restore)
    	borg extract ::$2
    	;;
    backup)
        cat | borg create ::{now} -
	borg prune \
        	--keep-hourly $KEEP_HOURLY \
        	--keep-daily $KEEP_DAYS \
        	--keep-weekly $KEEP_WEEKS \
        	--keep-monthly $KEEP_MONTHS \
        	--keep-yearly $KEEP_YEARS
        ;;
esac

Same explanation as with restic, you can save the password elsewhere or get it from a command, but Qubes backup already encrypt the data, so the repo encryption will mostly only add privacy.

/!\ You need to run the script with the parameter "init" the first time, in order to create the repository:

$ chmod +x borg.sh
$ ./borg.sh init

5.3. Configure Qubes backup §

Now, configure the Qubes backup tool:

  • Choose the VMs to backup
  • Check "Compress backups", because it's done before encryption it yields a better efficiency than compression done by restic on the encrypted data
  • Click Next
  • Choose the backup VM in the "Target qube" list
  • In the field "backup directory or command" type /home/user/restic.sh backup or /home/user/borg.sh backup depending on your choice
  • Pick a passphrase
  • Run the backup

6. Restoring a backup §

While it's nice to have backups, it's important to know how to use them. The setup doesn't add much complexity, and the helper script will ease your life.

On the backup VM, run ./borg.sh list (or the restic version) to display available snapshots in the repository, then use ./borg.sh restore $snap with the second parameter being a snapshot identifier listed in the earlier command.

You will obtain a file named stdin, this is the file to use in Qubes OS restore tool.

7. Warning §

If you don't always backup all the VMs, if you keep the retention policy like in the example above, you may lose data.

For example, if you have a KEEP_HOURLY=1, create a backup of all your VMs, and just after, you specifically want to backup a single VM, you will lose the previous full backup due to the retention policy.

In some cases, it may be better to not have any retention policy, or simply time based (keep snapshots which date < n days).

8. Conclusion §

Using this configuration, you get all the features of a industry standard backup solution such as integrity check, retention policy or remote encrypted storage.

9. Troubleshoot §

In case of an issue with the backup command, Qubes backup will display a popup message with the command output, this helps a lot debugging problems.

An easy way to check if the script works by hand is to run it from the backup VM:

echo test | ./restic.sh backup

This will create a new backup with the data "test" (and prune older backups, so take care!), if it doesn't work this is a simple way to trigger a new backup to solve your issue.

Stream your OpenBSD desktop audio to other devices

Written by Solène, on 05 May 2023.
Tags: #openbsd #streaming #icecast #hacking

Comments on Fediverse/Mastodon

1. Introduction §

Hi, back on OpenBSD desktop, I miss being able to use my bluetooth headphones (especially the Shokz ones that allow me to listen to music without anything on my ears).

Unfortunately, OpenBSD doesn't have a bluetooth stack, but I have a smartphone (and a few other computers), so why not stream my desktop sound to another device with bluetooh? Let's see what we can do!

I'll often refer to the "monitor" input source, which is the name of an input that provides "what you hear" from your computer.

While it would be easy to just allow a remote device to play music files, I want to stream the computer's monitor input, so it could be litteraly anything, and not just music files.

This method can be used on any Linux distribution, and certainly on other BSDs, but I will only cover OpenBSD.

2. The different solutions §

2.1. Icecast §

One simple setup is to use icecast, the program used by most web radios, and ices, a companion program to icecast, in order to stream your monitor input to the network.

The pros:

  • it works with anything that can read OGG from the network (any serious audio client or web browser can do this)
  • it's easy to set up
  • you can have multiple clients at once
  • secure (icecast is in a chroot, and other components are sending data or playing music)

The cons:

  • there is a ~10s delay, which prevents you from watching a video on your computer and listening the audio from another device (you could still set 10s offset, but it's not constant)
  • reencoding happens, which can slightly reduce the sound quality (if you are able to tell the difference)

2.2. Sndiod §

The default sound server in OpenBSD, namely sndiod, supports network streaming!

Too bad, if you want to use Bluetooth as an output, you would have to run sndiod on Linux (which is perfectly fine), but you can't use Bluetooth with sndiod, even on Linux.

So, no sndiod. Between two OpenBSD, or OpenBSD and Linux, it works perfectly well without latency, and it's a super simple setup, but as Bluetooth can't be used, I won't cover this setup.

The pros:

  • easy to setup
  • works fine

The cons:

  • no android support

2.3. Pulseaudio §

This sound server is available as a port on OpenBSD, and has two streaming modes: native-protocol-tcp and RTP, the former is exchanging pulseaudio internal protocol from one server to another which isn't ideal and prone to problems over a bad network, the latter being more efficient and resilient.

However, the RTP sender doesn't work on OpenBSD, and I have no interest in finding out why (the bug doesn't seem to be straightforward), but the native protocol works just fine.

The pros:

  • almost no latency (may depend of the network and remote hardware)
  • easy to setup

2.4. Snapcast §

Snapcast is an amazing piece of software that you can use to broadcast your audio toward multiple other client (using snapcast or a web page) with the twist that the audio will be synchronized on each client, allowing a multi room setup at no cost.

Unfortunately, I've not been able to build it on OpenBSD :(

The pros:

  • multi room setup with synchronized clients
  • compatible with almost any client able to display an HTML5 page

The cons:

  • playback latency
  • not so easy to setup

3. Setup §

Here are the instructions to setup different solutions.

3.1. Pulseaudio §

3.1.1. Client setup (OpenBSD) §

On the local OpenBSD, you need to install pulseaudio and ffmpeg packages.

You also need to set sndiod flags, using rcctl set sndiod flags -s default -m play,mon -s mon, this will allow you to use the monitor input through the device snd/0.mon.

Now, when you want to stream your monitor to a remote pulseaudio, run this command in your terminal:

ffmpeg -f sndio -i snd/0.mon -ar 44100 -f s16le - | pacat -s 10.42.42.199 --raw --process-time-msec=30 --latency-msec=30

The command is composed of two parts:

  • ffmpeg reading the monitor input and sending it to the pipe
  • pacat (pulseaudio cat) relaying the pipe input to the pulseaudio server 10.42.42.199, with some tweaks to reduce the latency

3.2. Server setup (the device with bluetooth) §

The setup is easy, but note that this doesn't involve any authentication or encryption, so please use this on trusted network, or through a VPN.

On a system with pulseaudio, type:

pacmd load-module module-native-protocol-tcp auth-anonymous=1 auth-ip-acl=192.168.1.0/24

This will load the module accepting network connections, the auth-anonymous option is there to simplify connection to the server, otherwise you would have to share the pulseaudio cookie between computers, which I recommend doing but on a smartphone this can be really cumbersome to do, and out of scope here.

The other option is pretty obvious, just give a list of IPs you want to allow to connect to the server.

If you want the changes to be persistent, edit /etc/pulse/default.pa to add the line load-module module-native-protocol-tcp auth-anonymous=1 auth-ip-acl=192.168.1.0/24.

On Android, you can install pulseaudio using Termux (available on f-droid), using the commands:

pkg install pulseaudio
pulseaudio --start --exit-idle-time=3600
pacmd load-module module-native-protocol-tcp auth-anonymous=1 auth-ip-acl=192.168.1.0/24

There is a project named PulseDroid, the original project has been unmaintained for 13 years, but someone took it back quite recently, unfortunately no APK are provided, and I'm still trying to build it to try, it should provide an easier user experience to run pulseaudio on Android.

PulseDroid gitlab repository

3.3. Icecast §

Using icecast, you will have to setup an icecast server, and locally use ices2 client to broadcast your monitor input. Then, any client can play the stream URL.

Install the component using:

pkg_add icecast ices--%ices2

3.3.1. Server part §

As suggested by the file /usr/local/share/doc/pkg-readmes/icecast, run the following commands to populate icecast's chroot:

cp -p /etc/{hosts,localtime,resolv.conf} /var/icecast/etc
cp -p /usr/share/misc/mime.types /var/icecast/etc

Edit /var/icecast/icecast.xml:

  • in the <authentication> node, change all the passwords. The only one you will need is the source password used to send the audio to icecast, but set all other passwords to something random.
  • in the <hostname> node, set the IP or hostname of the computer with icecast.
  • add a <bind-address> node to <listen-socket> using the example for 127.0.0.1, but use the IP of the icecast server, this will allow other to connect.

Keep in mind this is the bare minimum for a working setup, if you want to open it to the wide Internet, I'd strongly recommend reading icecast documentation before. Using a VPN may be wiser if it's only for private use.

We can start icecast and set it to start at boot:

rcctl enable icecast
rcctl start icecast

3.3.2. Broadcast part §

Then, to configure ices2, copy the file /usr/local/share/examples/ices2/ices-sndio.xml somewhere you feel comfortable for storing user configuration files. The example file is an almost working template to send sndio sources to icecast.

Edit the file, under the <instance> node:

  • modify <hostname> with the hostname used in icecast.
  • modify <password> with the source password defined earlier.
  • modify <mount> to something ending in .ogg of your liking, this will be the filename in the URL (can be /stream.ogg if you are out of ideas).
  • set <yp> to 0, otherwise the stream will appear on the icecast status page (you may want to have it displayed though).

Now, search for <channels> and set it to 2 because we want to broadcast stereo sound, and set <downmix> to 0 because we don't need to merge both channels into a mono output. (If those values aren't in sync, you will have funny results =D)

When you want to broadcast, run the command:

env AUDIORECDEVICE=snd/0.mon ices2 ices-sndio.xml

With any device, open the url http://<hostname>:8000/file.ogg with file.ogg being what you've put in <mount> earlier. And voilà, you have a working local audio streaming!

4. Limitations §

Of course, the setup isn't ideal, you can't use your headset microphone or buttons (using MPRIS protocol).

5. Conclusion §

With these two setup, you have a choice for occasionnaly streaming your audio to another device, which may have bluetooth support or something making it interesting enough to go through the setup.

I'm personally happy to be able to use bluetooth headphones through my smartphone to listen to my OpenBSD desktop sound.

6. Going further §

If you want to directly attach bluetooth headphones to your OpenBSD, you can buy an USB dongle that will pair to the headphones and appear as a sound card to OpenBSD.

jcs@ article about Bluetooth audio on OpenBSD

Installing Alpine as a Desktop

Written by Solène, on 30 April 2023.
Tags: #linux #alpine

Comments on Fediverse/Mastodon

1. Introduction §

While I like Alpine because it's lean and minimal, I have always struggled to install it for a desktop computer because of the lack of "meta" packages that install everything.

However, there now is a nice command that just picks your desktop environment of choice and sets everything up for you.

This article is mostly a cheat sheet to help me remember how to install Alpine using a desktop environment, NetworkManager, man pages etc... Because Alpine is still a minimalist distribution and you need to install everything you think is useful.

Alpine Linux official project page

UPDATE 2023-05-03: I've been told that such a guide already existed in Alpine wiki 😅.

Alpine Wiki about Post installation

2. Setup §

During the installation process started by setup, just type syscrypt for full disk encryption installation.

2.1. Installing a desktop environment §

The most missing part when using Alpine for me was figuring out which packages to install and which services to run to get a working GNOME or Plasma.

But now, just run setup-desktop and enjoy.

2.2. Installing man pages §

A few packages are required to be able to read man pages.

# apk add docs less

If a man page is missing, search for the package name with the -doc suffix, using apk search $package | grep doc.

2.3. Internationalization §

If you want your software in a language other than English, just use apk add lang, this will install the -lang packages for each installed package.

2.4. NetworkManager §

By default, the installer will ask you to set up networking, but if you want NetworkManager, you need to install it, enable it and disable the other services.

As I prefer to avoid duplication of documentation, please refer to the relevant Wiki page.

Alpine Wiki about NetworkManager

You may want to add a few more packages:

apk add networkmanager-tui
apk add networkmanager-openvpn-lang
apk add networkmanager-openvpn
apk add networkmanager-wifi

2.5. Bluetooth §

Nothing special for Bluetooth, except NetworkManager will make it easier to use. The wiki has setup instructions.

Alpine Wiki about Bluetooth

2.6. Use a recent kernel §

By default, Alpine Linux sticks to Long Term Support (LTS) kernels, which is fine, but for newer hardware, you may want to run the latest kernel available.

Fortunately, the Alpine community repository provides the linux-edge package for the latest version.

2.7. Fonts §

You may want to install some extra fonts, because by default there is only the bare minimum, and your programs will look ugly.

Alpine Wiki about Fonts

2.8. Emojis §

Having working emojis is important for me now, and Alpine only provide a default emoji font with black-and-white pictures, without the complete set.

It's a single package to add in order to get your emojis working. The revelant Wiki page is linked below.

Alpine Wiki about Emojis

2.9. Keep binary packages in cache §

If you want to keep all the installed packages in cache (so you could keep them for reinstalling, or share on your network), it's super easy.

Run setup-apkcache and choose a location (or even pass it as a parameter), you're done. It's very handy for me because when I need to use Alpine in a VM, i just hook it to my LAN cache and I don't have to download packages again and again.

3. Conclusion §

Alpine Linux is becoming a serious, viable desktop Linux distribution, not just for containers or servers. It's still very minimalist and doesn't hold your hand, so while it's not for everyone, it's becoming accessible to enthusiasts and not just hardcore users.

I suppose it's a nice choice for people who enjoy minimalism and don't like SystemD.

4. Credits §

Thanks to raspbeguy for the various hints about Alpine, and for making me trying it once again.

Set up your own CalDAV and CardDAV servers on OpenBSD

Written by Solène, on 23 April 2023.
Tags: #caldav #carddav #openbsd #selfhosting

Comments on Fediverse/Mastodon

1. Introduction §

Calendar and contacts syncing, it's something I pushed away for too long, but when I've lost data on my phone and my contacts with it, setting up a local CalDAV/CardDAV server is the first thing I did.

Today, I'll like to show you how to set up the server radicale to have your own server.

Radicale official project page

Basically, CalDAV (for calendars and to-do lists) and CardDAV (for contacts) are exchange protocols to sync contacs and calendars between devices.

2. Setup §

On OpenBSD 7.3, the latest version of radicale is radicale 2, available as a package with all the service files required for a quick and efficient setup.

You can install radicale with the following command:

# pkg_add radicale

After installation, you will have to edit the file /etc/radicale/config in order to make a few changes. The syntax looks like INI files with sections between brakets and then key/values on separate lines.

For my setup, I made my radicale server to listen on the IP 10.42.42.42 and port 5232, and I chose to use htpasswd files encrypted in bcrypt to manage users. This was accomplished with the following piece of configuration:

[server]
hosts = 10.42.42.42:5232

[auth] 
type = htpasswd 
htpasswd_filename = /etc/radicale/users
htpasswd_encryption = bcrypt

After saving the changes, you need to generate the file /etc/radicale/users to add credentials and password in it, this is done using the command htpasswd.

In order to add the user solene to the file, use the following command:

# cd /etc/radicale
# htpaswd users solene
# chown _radicale /etc/radicale/users

Now everything is ready, you can enable radicale to run at boot, and start it now, using rcctl to manage the service like in:

# rcctl enable radicale
# rcctl start radicale

3. Managing calendars and contacts §

Now you should be able to reach radicale on the address it's listening, in my example it's http://10.42.42.42:5232/ and use your credentials to log in.

Then, just click on the link "Create new addressbook or calendar", and complete the form.

Back on the index, you will see each item managed by radicale and the URL to access it. When you will configure your devices to use CalDAV and CardDAV, you will need the crendentials and the URL.

4. Conclusion §

Radicale is very lightweight and super easy to configure, and I finally have a proper calendar synchronization on my computers and smartphone, which turned to be very practical.

5. Going further §

If you want to setup HTTPS for radicale, you can either use a certificate file and configure radicale to use it, or use a reverse http proxy such as nginx and handle the certificate there.

Trying some Linux distributions to free my Steam Deck

Written by Solène, on 16 April 2023.
Tags: #gaming #linux

Comments on Fediverse/Mastodon

1. Introduction §

As the owner of a Steam Deck (a handeld PC gaming device), I wanted to explore alternatives to the pre-installed SteamOS you can find on it. Fortunately, this machine is a plain PC with UEFI Firmware allowing you to boot whatever you want.

2. What's the deck? §

It's like a Nintendo Switch, but much bigger. The "deck" is a great name because it's really what it looks like, with two touchpads and four extra buttons behind the deck. By default, it's running SteamOS, an ArchLinux based system working in two modes:

  • Steam gamepadUI mode with a program named gamescope as a wayland compositor, everything is well integrated like you would expect from a gaming device. Special buttons trigger menus, integration with monitoring tool to view FPS, watts consumption, TDP limits, screen refresh rate....
  • Desktop mode, using KDE Plasma, and it acts like a regular computer

Unfortunately for me, I don't like ArchLinux and I wanted to understand how the different modes were working, because on Steam, you just have a button menu to switch from Gaming to Desktop, and a desktop icon to switch from desktop to gaming.

Steam Deck official website (with specs)

Here is a picture I took to compare a Nintendo Switch and a Steam Deck, it's really beefy and huge, but while its weight is higher than the Switch, I prefer how it holds and the buttons' placement.

Steam Deck side by side with a Nintendo Switch
Steam Deck side by side with a Nintendo Switch

3. Alternatives §

And after starting my quest to free my Deck, I found there were already serious alternatives. Let's explore them.

3.1. HoloISO §

This project purpose is to reimplement SteamOS the best it can, but only using open source components. They also target alternative devices if you want to have a Steam Deck experience.

Project page

My experience wasn't great with it, once installation was done, I had to log in into Steam, and at every reboot it was asking me to log-in again. As the project was mostly providing the same experience based on ArchLinux, I wasn't really interested to look into it further.

3.2. ChimeraOS §

This project purpose is to give Steam Deck user (or similar device owners) an OS that would fit the device, it's currently offering a similar experience, but I've read plans to offer alternative UI. On top of that, they integrated a web server to manage emulations ROMS, or Epic Games and GOG installer, instead of having to fiddle with Lutris, minigalaxy or Heroic game launcher to install games from these store.

The project also has many side-projects such as gamescope-session, chimera or forks with custom patches.

Project official website

My experience was very good, the web server to handle GOG/Epic is a very cool idea and worked well, the Steam GamepadUI was working as well.

3.3. Jovian-NixOS §

This project is truly amazing, it's currently what I'm running on my own devices. Let's use NixOS with some extra patches to run your Deck, and it's just working fine!

Jovian-NixOS (in reference to Neptune, the Deck codename) is a set of configuration to use with NixOS to adapt to the Steam Deck, or any similar handeld device. The installation isn't as smooth as the two other above because you have to install NixOS from console, write a bit of configuration, but the result is great. It's not for everyone though.

Project page

Obviously, my experience is very good. I'm in full control of the system, thanks to NixOS declarative approach, no extra services running until I want to, it even makes a great Nix remote builder...

3.4. Plain linux installed like a regular computer §

The first attempt was to install openSUSE on the Deck like I would do on any computer. The experience was correct, installation went well, and I got in GNOME without issues.

However, some things you must know about the Deck:

  • patches are required on the Linux kernel to have proper fan control, they work out of the box now but the fan curve isn't ideal, like the fan will never stop even under low temperature
  • in Desktop mode, the controller is seen as a poor mouse with triggers to click, the touchscreen is working, but Linux isn't really ready to be used like a tablet, you need Steam in big picture mode to make the controller useful
  • many patches here and there (Mesa, mangohud, gamescope) are useful to improve the experience

In order to switch between Desktop and Gaming mode, I found a weird setup that was working for me:

  • gaming mode is started by automatically log-in my user on tty1 with the user .bashrc checking if running on tty1 and running steam over gamescope
  • desktop mode is started by setting automatic login in GDM
  • a script started from a .desktop file that would toggle between gaming and desktop mode. Either by killing gamescope and starting GDM, or by stopping gdm and startin tty1. The .desktop was added to Steam, so from Steam or GNOME I was able to switch to the other. It worked surprisingly well.

I turned out Steam GamepadUI with Gamescope button "Switch to desktop mode" is using a dbus signal to switch to desktop, distributions above handle it correctly.

Although it was mostly working, my main issues were:

  • No fan curve control because it's not easy to find the kernel patches, and then run the utility to control the fans, my deck was constantly doing some fan noise, and it was irritating
  • I had no idea how to allow firmware update (OS above support that)
  • Integration with mangohud was bad, and performance control in Gaming mode wasn't working
  • Sometimes, XWayland would crash or stay stuck when starting a game from Gaming mode

But, despite these issues, performance was perfectly fine, as well as battery life. But usability should be priority for such a device, and it didn't work very well here.

4. Conclusion §

If you already enjoy your Steam Deck the way it is, I recommend you to stick to SteamOS. It does the job fine, allows you to install programs from Flatpak, and you can also root it if you really need to install system packages.

If you want to do more on your Deck (use it as a server maybe? Who knows), you may find it interesting to get everything under your control.

5. Pro tip §

I'm using syncthing on my Steam Deck and other devices to synchronize GOG/Epic save games, Steam cloud is neat, but with one minute per game to configure syncthing, you have something similar.

Nintendo Switch emulation works fine on Steam Deck, more about that soon :)

Steam Deck displaying the Switch game Pokémon Arceus Legends
Steam Deck displaying the Switch game Pokémon Arceus Legends

Quelques Haikus pour début 2023

Written by Solène, on 09 April 2023.
Tags: #haiku

Comments on Fediverse/Mastodon

Une petite sélection de haikus qui ont été publiés sur Mastodon, cela dit, il ne sont pas toujours bien fichus mais ce sont mes premiers, espérons que l'expérience m'aide à faire mieux par la suite.

Merle qui chasse
Un ciel bleu teinté de blanc
Le thym en fleurs
Plateaux enneigés
Bien au chaud et à l'abri -
Violente tempête
Antarctique -
Monuments cyclopéens
Hiver ténébreux
Petit étang gris -
Tapissé de feuilles
Tout en silence
Plage au soleil
L'oiseau en laisse dans le ciel -
Son fil, cerf-volant
Idées et pensées -
Comme l'orage d'été
Tombent du ciel
Grâce matinée
Dimanche, changement d'heure -
Le chant des oiseaux
Maladie, douleur
Climat doux, bourgeons en fleurs -
Le temps, guérison
Le vent dans les feuilles -
Le ruissellement de l'eau
Forêt en éveil
Les rues silencieuses
L'aube qui peine à se lever -
Jardin givré
Une nuit de pleine lune
Barbecue par des amis -
Vacances d'été
Des pommes de terre
Plateau de charcuterie -
Copieuse raclette
Ciel bleu printanier
fleurs, abeilles, tout se réveil -
Balade en forêt

How to setup a local network cache for Flatpak

Written by Solène, on 05 April 2023.
Tags: #linux #flatpak #efficiency

Comments on Fediverse/Mastodon

1. Introduction §

As you may have understood by now, I like efficiency on my systems, especially when it comes to network usage due to my poor slow ADSL internet connection.

Flatpak is nice, I like it for many reasons, and what's cool is that it can download only updated files instead of the whole package again.

Unfortunately, when you start using more and more packages that are updated daily, and which require subsystems like NVIDIA drivers, MESA etc... this adds up to quitea lot of daily downloads, and multiply that by a few computers and you gets a lot of network traffic.

But don't worry, you can cache it on your LAN to download updates only once.

2. Setup §

As usual for this kind of job, we will use Nginx on a local server on the network, and configure it to act as a reverse proxy to the flatpak repositories.

This requires modifying the URL of each flatpak repository on the machines, it's a one time operation.

Here is the configuration you need on your Nginx to proxy Flathub:

map $status $cache_header {
    200     "public";
    302     "public";
    default "no-cache";
}

server {
    listen 0.0.0.0:8080; # you may want to listen on port 80, or add TLS
    server_name my-cache.local; # replace this with your hostname, or system IP

    # flathub cache
    set $flathub_cache https://dl.flathub.org;

    location /flathub/ {
        rewrite  ^/flathub/(.*) /$1 break;
        proxy_cache flathub;
        proxy_cache_key     "$request_filename";
        add_header Cache-Control $cache_header always;
        proxy_cache_valid   200 302     300d;
        expires max;
        proxy_pass  $flathub_cache;
    }
}

proxy_cache_path    /var/cache/nginx/flathub/cache levels=1:2
    keys_zone=flathub:5m
    max_size=20g
    inactive=60d
    use_temp_path=off;

This will cause nginx to proxy requests to the flathub server, but keep files in a 20 GB cache.

You will certainly need to create the /var/cache/nginx/flathub directory, and make sure it has the correct ownership for your system configuration.

If you want to support another flatpak repository (like Fedora's), you need to create a new location, and new cache in your nginx config.

3. Client configuration §

On each client, you need to change the URL to reach flathub, in the example above, the URL is http://my-cache.local:8080/flathub/repo/.

You can change the URL with the following command:

flatpak remote-modify flathub --url=http://my-cache.local:8080/flathub/repo/`

Please note that if you add flathub repo, you must use the official URL to have the correct configuration, and then you can change its URL with the above command.

4. Revert the changes §

If you don't want to use the cache anymore , just revert the flathub url to its original value:

flatpak remote-modify flathub --url=https://dl.flathub.org/repo/

5. Conclusion §

Our dear nginx is still super useful as a local caching server, it's super fun to see some updates going at 100 MB/s from my NAS now.

Detect left over users and groups on OpenBSD

Written by Solène, on 03 April 2023.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

If you use OpenBSD and administrate machines, you may be aware that packages can install new dedicated users and groups, and that if you remove a package doing so, the users/groups won't be deleted, instead, pkg_delete displays instructions about deletion.

In order to keep my OpenBSD systems clean, I wrote a script looking for users and groups that have been installed (they start by the character _), and check if the related package is still installed, if not, it outputs instructions that could be run in a shell to cleanup your system.

2. The code §

#!/bin/sh

SYS_USERS=$(mktemp /tmp/system_users.txt.XXXXXXXXXXXXXXX)
PKG_USERS=$(mktemp /tmp/packages_users.txt.XXXXXXXXXXXXXXX)

awk -F ':' '/^_/ && $3 > 500 { print $1 }' /etc/passwd | sort > "$SYS_USERS"
find /var/db/pkg/ -name '+CONTENTS' -exec grep -h ^@newuser {} + | sed 's/^@newuser //' | awk -F ':' '{ print $1 }' | sort > "$PKG_USERS"

BOGUS=$(comm -1 -3 "$SYS_USERS" "$PKG_USERS")
if [ -n "$BOGUS" ]
then
    echo "Bogus users/groups (missing in /etc/passwd, but a package need them)" >/dev/stderr
    echo "$BOGUS" >/dev/stderr
fi

EXTRA=$(comm -2 -3 "$SYS_USERS" "$PKG_USERS")
if [ -n "$EXTRA" ]
then
    echo "Extra users" >/dev/stderr

    for user in $EXTRA
    do
        echo "userdel $user"
        echo "groupdel $user"
    done
fi

rm "$SYS_USERS" "$PKG_USERS"

2.1. How to run §

Write the content of the script above in a file, mark it executable, and run it from the shell, it should display a list of userdel and groupdel commands for all the extra users and groups.

3. Conclusion §

With this script and the package sysclean, it's quite easy to keep your OpenBSD system clean, as if it was just a fresh install.

4. Limitations §

It's not perfect in its current state because if you deleted an user, the according group that is still left won't be reported.

Monitor your remote host network quality using smokeping on OpenBSD

Written by Solène, on 26 March 2023.
Tags: #nocloud #openbsd #networking

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1. Introduction §

If you need to more the network quality of a link, or the network availability of a remote host, I'd recommend you to take a look at Smokeping.

Smokeping official Website

Smokeping is a Perl daemon that will regularly run a command (fping, some dns check, etc…) multiple times to check the availability of the remote host, but also the quality of the link, including the standard deviation of the response time.

It becomes very easy to know if a remote host is flaky, or if the link where Smokeping runs isn't stable any more when you see that all the remote hosts have connectivity issues.

Let me explain how to install and configure it on OpenBSD 7.2 and 7.3.

2. Installation §

Smokeping comes in two parts, but they are in the same package, the daemon components to run it 24/7 to gather metrics, and the fcgi component used to render the website for visualizing data.

First step is to install the smokeping package.

# pkg_add smokeping

The package will also install the file /usr/local/share/doc/pkg-readmes/smokeping giving explanations for the setup. It contains a lot of instructions, from the setup to advanced configuration, but without many explanations if you are new to smokeping.

2.1. The daemon §

Once you installed the package, the first step is to configure smokeping by editing the file /etc/smokeping/config as root.

Under the *** General *** section, you can change the variables owner and contact, this information is displayed on Smokeping HTML interface, so if you are in company and some colleague look at the graphs, they can find out who to reach if there is an issue with smokeping or with the links. This is not useful if you use it for yourself.

Under the *** Alerts *** section, you can configure the emails notifications by configuring to and from to match your email address, and a custom address for smokeping emails origin.

Then, under *** Targets *** section, you can configure each host to monitor. The syntax is unusual though.

  • lines starting with + SomeSingleWord will create a category with attributes and subcategories. Attribute title is used to give a name to it when showing the category, and menu is the name displayed on the sidebar on the website.
  • lines starting with ++ SomeSingleWord will create a subcategory for a host. Attributes title and menu works the same as the first level, and host is used to define the remote host to monitor, it can be a hostname or an IP address.

That's for the simplest configuration file. It's possible to add new probes such as "SSH Ping", DNS, Telnet or LDAP...

Let me show a simple example of targets configuration I'm using:

*** Targets ***

probe = FPing

menu = Top
title = Network Latency Grapher
remark = Welcome to the SmokePing

+ Remote
menu= Remote
title= Remote hosts

++ Persopw

menu = perso.pw
title = My server perso.pw
host = perso.pw

++ openportspl

menu = openports.pl
title = openports.pl VM at openbsd.amsterdam
host = openports.pl

++ grifonfr

menu = grifon.fr
title = grifon.fr VPN endpoint
host = 89.234.186.37

+ LAN
menu = Lan
title = Lan network at home

++ solaredge

menu = solaredge
title = solardedge
host = 10.42.42.246

++ modem

menu = ispmodem
title = ispmodem
host = 192.168.1.254

Now you configured smokeping, you need to enable the service and run it.

# rcctl enable smokeping
# rcctl start smokeping

If everything is alright, rcctl check smokeping shouldn't fail, if so, you can read /var/log/messages to find why it's failing. Usually, it's a + line that isn't valid because of a non-authorized character or a space.

I recommend to always add a public host of a big platform that is known to be working reliably all the time, to have a comparison point against all your other hosts.

2.2. The Web Interface §

Now the daemon is running, you certainly want to view the graphs produced by Smokeping. Reusing the example from the pkg-readme file, you can configure httpd web server with this:

    server "smokeping.example.org" {
	listen on * port 80
	location "/smokeping/smokeping.cgi*" {
	    fastcgi socket "/run/smokeping.sock"
	    root "/"
	}
    }

Your service will be available at the address http://smokeping.example.org/smokeping/smokeping.cgi.

For this to work, we need to run a separate FCGI server, fortunately packaged as an OpenBSD service.

# rcctl enable smokeping_fcgi
# rcctl start smokeping_fcgi

Note that there is a way to pre-render all the HTML interface by a cron job, but I don't recommend it as it will drain a lot of CPU for nothing, except if you have many users viewing the interface and that they don't need interactive zoom on the graphs.

3. Conclusion §

Smokeping is very effective because of the way it renders data, you can easily spot issues in your network that a simple ping or response time wouldn't catch.

Please note it's better to have two smokeping setup at different places in order to monitor each other remote smokeping link quality. Otherwise, if a remote host appear flaky, you can't entirely be sure if the Internet access of the smokeping is flaky, or if it's the remote host, or a peering issue.

Here is the 10 days graph for a device I have on my LAN but connected to the network using power line networking.

Monitoring graph of a device connected on LAN using power line network
Monitoring graph of a device connected on LAN using power line network

Don't forget to read /usr/local/share/doc/pkg-readmes/smokeping and the official documentation if you want a more complicated setup.

L'État m'impose Google (ou Apple)

Written by Solène, on 17 March 2023.
Tags: #life #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

C'est rare, mais ceci est un message de ras-le-bol.

Ayant besoin d'une formation, pour finir les procédures en lignes sur un compte CPF (Compte Formation Professionnelle), j'ai besoin d'avoir une "identité numérique +".

Sur le principe, c'est cool, c'est un moyen de créer un compte en validant l'identité de la personne via une pièce d'identité, jusque là c'est normal et plutot bien pensé.

2. Le problème §

Le gros soucis, c'est qu'une fois les formalités terminées, il faut installer l'application Android / iOS sur son téléphone, et là soucis.

Google Play : L'Identité Numérique La Poste

Ayant libéré mon téléphone Android de Google grâce à LineageOS, j'ai choisi de ne pas installer Google Play pour être 100% dégooglisé, et j'installe mes applications depuis le dépôt F-droid qui couvre tous mes besoins.

Site du projet F-droid

Site du projet LineageOS

Dans ma situation, il existe une solution pour installer des applications (heuresement très rares) nécessaires pour certains services, qui consiste à utiliser "Aurora Store" depuis mon téléphone pour télécharger un APK de Google Play (le fichier d'installation d'application) et l'installer. Pas de soucis, j'ai pu installer le programme de La Poste.

Le problème, c'est que je le lance et j'obtiens ce magnifique message "Erreur, vous devez installer l'application depuis Google Play", et là, je ne peux absolument rien faire d'autre que de quitter l'application.

Message d
Message d'erreur de l'application La Poste sur LineageOS sans services Google

Et voilà, je suis coincée, l'État m'impose d'utiliser Google pour utiliser ses propres services 🙄, mes solutions sont les suivantes :

  • installer les services Google sur mon téléphone, et ça me ferait bien mal au coeur car cela va à l'encontre de mes valeurs
  • installer l'application dans un émulateur Android avec les services Google, c'est absolument pas pratique mais ça résoud le problème
  • m'asseoir sur l'argent de mon compte de formation (500 € / an)
  • remonter le problème publiquement en espérant que cela fasse changer quelque chose, au moins que l'on puisse installer l'application sans services Google

3. Message à La Poste §

S'il vous plait, trouvez une solution pour que l'on puisse utiliser votre service SANS avoir recours à Google.

4. Extras §

Il semblerait que l'on puisse éviter d'utiliser l'application France Connect + via le formulaire suivant (merci Linuxmario)

Je ne remplis pas les conditions pour utiliser france connect +

Launching on Patreon

Written by Solène, on 13 March 2023.
Tags: #blog #life #patreon

Comments on Fediverse/Mastodon

1. Introduction §

Let me share some breaking news, if you enjoy this blog and my open source work, now you can sponsor me through the service Patreon.

Patreon page to sponsor me

Why would you do that in the first place? Well, this would allow me to take time off my job, and spend it either writing on the blog, or by contributing to open source projects, mainly OpenBSD or a bit of nixpkgs.

I've been publishing on the blog for almost 7 years now, for the most recent years, I've been writing a lot here, and I still enjoy doing so! However, I have a less free time now, and I'd prefer to continue writing here instead of working at my job full time. I've been ocasionaly receiving donation for my blog work, but one-shot gifts (I appreciate! :-) ) won't help me much against regular monthly incomes that I can expect, and help me to organize myself with my job.

2. What's the benefit for Patrons? §

I chose Patreon because the platform is reliable and offers managing some extras for the people patronizing me.

Let be clear about the advantages:

  • you will ocasionaly be offered to choose the topic for the blog post I'm writing. I often can't decide what to write about when I look at my pipe of ideas.
  • you will have access to the new blog posts a few days in advance.
  • you give me incentive to write better content in order to make you happy of your expenses.

3. What won't change §

This may sound scary to some I suppose, so let's answer some questions in advance:

  • the blog will stay free for everyone.
  • the blog will stay JS-free, and no design change are to be expected.
  • the blog won't include ads, sponsored ads or any "influencer" style things.
  • publishing on alternate protocols gopher and gemini will continue
  • content will be distributed under a CC-BY-4.0 licence (free to use/reuse).

4. Just a note §

It's hard for me to frame exactly what I'll be working on. I include the OpenBSD webzine as an extension of the blog, and sometimes ports work too because I'm writing about a program, I go down the rabbit-hole of updating it, and then there is a whole story to tell.

To conclude, let me thank you if you plan to support me financially, every bit will help, even small sponsors. I'm really motivated by this, I want to promote community driven open source projects such as OpenBSD, but I also want to cover a topic that matters a lot to me which is old hardware reuse. I highlighted this with the old computer challenge, but this is also the core of all my self-hosting articles and what drives me when using computers.

5. Asked Questions §

I'll collect here asked questions (not yet frequently asked though), and my answers:

  • Do you accept crypto currency? The answer is no.

Linux $HOME encryption with ecryptfs

Written by Solène, on 12 March 2023.
Tags: #linux #encryption #privacy

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1. Introduction §

In this article, I'd like to share with you about the Linux specific feature ecryptfs, which allows users to have encrypted directories.

While disk encryption done with cryptsetup/LUKS is very performant and secure, there are some edge cases in which you may want to use ecryptfs, whether the disk is LUKS encrypted or not.

I've been able to identify a few use cases making ecryptfs relevant:

  • a multi-user system, people want their files to be private (and full disk encryption wouldn't help here)
  • an encrypted disk on which you want to have an encrypted directory that is only available when needed (preventing a hacked live computer to leak important files)
  • a non-encrypted disk on which you want to have an encrypted directory/$HOME instead of reinstalling with full disk encryption

ecryptfs official website

2. Full $HOME Encryption §

In this configuration, you want all the files in the $HOME directory of your user to be encrypted. This works well and especially as it integrates with PAM (the "login manager" in Linux) so it unlocks the files upon login.

I tried the following setup on Gentoo Linux, the setup is quite standard for any Linux distribution packaging ecryptfs-utils.

2.1. Setup §

As I don't want to duplicate documentation effort, let me share two links explaining how to set up the home encryption for a user.

Gentoo Wiki: Encrypt a home directory with ECryptfs

ArchWiki: eCryptfs

Both guides are good, they will explain thoroughly how to set up ecryptfs for a user.

However, here is a TLDR version:

  1. install ecryptfs-utils and make sure ecryptfs module is loaded at boot
  2. modify /etc/pam.d/system-auth to add ecryptfs unlocking at login (3 lines are needed, at specific places)
  3. run ecryptfs-migrate-home -u $YOUR_USER as root to convert the user home directory into an encrypted version
  4. delete the old unencrypted home which should be named after /home/YOUR_USER.xxxxx where xxxxx are random characters (make sure you have backups)

After those steps, you should be able to log in with your user, mount outputs should show a dedicated entry for the home directory.

3. Private directory encryption §

In this configuration, you will have ecryptfs encrypting a single directory named Private in the home directory.

That can be useful if you already have an encrypted disk, but you have very secret files that must be encrypted when you don't need them, this will protect file leak on a compromised running system, except if you unlock the directory while the system is compromised.

This can also be used on a thrashable system (like my netbook) that isn't encrypted, but I may want to save a few files there that are private.

3.1. Setup §

That part is really easy:

  1. install a package named ecryptfs-utils (may depend on your distribution)
  2. run ecryptfs-setup-private --noautomount
  3. Type your login password
  4. Press enter to use an auto generated mount passphrase (you don't use this one to unlock the directory)
  5. Done!

The mount passphrase is used in addition to the login passphrase to encrypt the files, you may need it if you have to unlock backuped encrypted files, so better save it in your password manager if you make backup of the encrypted files.

You can unlock the access to the directory ~/Private by typing ecryptfs-mount-private and type your login password. Congratulations, now you have a local safe for your files!

4. Performance §

Ecryptfs was available in older Ubuntu installer releases as an option to encrypt a user home directory without the full disk, it seems it has been abandoned due to performance reasons.

I didn't make extensive benchmarks here, but I compared the writing speed of random characters into a file on an unencrypted ext4 partition, and the ecryptfs private directory on the same disk. On the unencrypted directory, it was writing at 535 MB/s while on the ecryptfs it was only writing at 358 MB/s, that's almost 33% slower. However, it's still fast enough for a daily workstation. I didn't measure the time to read or browse many files, but it must be slower. A LUKS encrypted disk should only have a performance penalty of a few percent, so ecryptfs is really not efficient in comparison, but it's still fast enough if you don't do database operation on it.

5. Security shortcoming §

There are extra security shortcomings coming with ecryptfs: when using your encrypted files unlocked, they may be copied in swap or in temporary directories, or in cache.

If you use the Private encrypted directories, for instance, you should think that most image reader will create a thumbnail in your HOME directory, so pictures in Private may have a local copy that is available outside the encrypted directory. Some text editors may cache a backup file in another directory.

If your system is running a bit out of memory, data may be written to the swap file, if it's not encrypted then one may be able to recover files that were opened during that time. There is a command ecryptfs-setup-swap from the ecryptfs package which check if the swap files are encrypted, and if not, propose to encrypt them using LUKS.

One major source of leakage is the /tmp/ directory, that may be used by programs to make a temporary copy of an opened file. It may be safe to just use a tmpfs filesystem for it.

Finally, if you only have a Private directory encrypted, don't forget that if you use a file browser to delete a file, it may end up in a trash directory on the unencrypted filesystem.

6. Troubleshooting §

6.1. setreuid: Operation not permitted §

If you get the error setreuid: Operation not permitted when running ecryptfs commands, this mean the ecryptfs binaries aren't using suid bit. On Gentoo, you have to compile ecryptfs-utils with the USE suid.

7. Conclusion §

Ecryptfs is can be useful in some real life scenarios, and doesn't have much alternative. It's especially user-friendly when used to encrypt the whole home because users don't even have to know about it.

Of course, for a private encrypted directory, the most tech-savvy can just create a big raw file and format it in LUKS, and mount it on need, but this mean you will have to manage the disk file as a separate partition with its own size, and scripts to mount/umount the volume, while ecryptfs offers an easy secure alternative with a performance drawback.

Using GitHub Actions to maintain Gentoo packages repository

Written by Solène, on 04 March 2023.
Tags: #gentoo #automation

Comments on Fediverse/Mastodon

1. Introduction §

In this blog post, I'd like to share how I had fun using GitHub actions in order to maintain a repository of generic x86-64 Gentoo packages up to date.

Built packages are available at https://interbus.perso.pw/ and can be used in your binrepos.conf for a generic x86-64 packages provider, it's not building many packages at the moment, but I'm open to add more packages if you want to use the repository.

GitHub Project page: Build Gentoo Packages For Me

2. Why §

I don't really like GitHub, but if we can use their CPU for free for something useful, why not? The whole implementation and setup looked fun enough that I should give it a try.

I was using a similar setup locally to build packages for my Gentoo netbook using a more powerful computer, so it was actually achievable, so I had to try. I don't have much use of it myself, but maybe a reader will enjoy the setup and do something similar (maybe not for Gentoo).

My personal infrastructure is quite light, with only an APU router plus a small box with an Atom CPU as a NAS, I was looking for a cheap way to keep their Gentoo systems running without having to compile locally.

3. Challenges §

Building a generic Gentoo packages repository isn't straighforward for a rew reasons:

  • compilation flags must match all the consumers' architecture
  • default USE flags must be useful for many
  • no support for remote builders
  • the whole repository must be generated on a single machine with all the files (can't be incremental)

Fortunately, there are Gentoo containers images that can be used to start a fresh Gentoo, and from there, build packages from a clean system every time. Packages have to be added into the container before each change, otherwise the file Packages that will be generated as a repository index won't contain all the files.

Using a -march=x86-64 compiler flag allows targeting all the amd64 systems, at the cost of less optimized binaries.

For the USE flags, a big part of Gentoo, I chose to select a default profile and simply stick with it. People using the repository could still change their USE flags, and only pick the binary packages from the repo if they still match expectations.

4. Setup §

We will use GitHub actions (Free plan) to build packages for a given Gentoo profile, and then upload it to a remote server that will share the packages over HTTPS.

The plan is to use a docker image of a stage3 Gentoo provided by the project gentoo-docker-images, pull previously built packages from my server, build new packages or updating existing packages, and push the changes to my server. Meanwhile, my server is serving the packages over https.

GitHub's actions are a feature from GitHub allowing to create Continuous Integration easy by providing "actions" (reusable components made by other) that you organize in steps.

For the job, I used the following steps on an Ubuntu system:

  1. Deploy SSH keys (used to pull/push packages to my server) stored as secrets in the GitHub project
  2. Checkout the sources of the project
  3. Make a local copy of the packages repository
  4. Create a container image based on the Gentoo stage3 + instructions to run
  5. Run the image that will use emerge to build the packages
  6. Copy the new repository on the remote server (using rsync to copy the diff)

GitHub project page: Gentoo Docker Images

5. Problems encountered §

While the idea is simple, I faced a lot of build failures, here is a list of problems I remember.

5.1. Go is failing to build (problem is Docker specific) §

For some reasons, Go was failing to build with a weird error, this is due to some sandboxing done by emerge that wasn't allowed by the Docker environment.

The solution is to loose the sandboxing with FEATURES="-ipc-sandbox -pid-sandbox -sandbox -usersandbox" in /etc/portage/make.conf. That's not great.

5.2. Raw stage3 is missing pieces §

The starter image is a stage3 of Gentoo, it's quite bare, one critical package missing to build other but never pulled as dependency is kernel sources.

You need to install sys-kernel/gentoo-sources if you want builds to succeed for many packages.

5.3. No merged-usr profile §

The gentoo docker images repository isn't provided merged-usr profiles (yet?), I had to install merged-usr and run it, to have a correct environment matching the selected profile.

5.4. Compilation is too long §

The job time is limited to 6h00 on the free plan, I added a timeout for the emerge doing the building job to stop a bit earlier, to let it some time to push the packages to the remote server, this will allow saving time for the next run. Of course, this only works until a single package require more than the timeout time to build (but it's quite unlikely given the CI is fast enough).

6. Security §

One has to trust GitHub actions, GitHub employees may have access to jobs running there, and could potentially compromise built packages using a rogue container image. While it's unlikely, this is a possibility.

Also, please note that the current setup doesn't sign the packages. This is something that could be added later, you can find documentation on the Gentoo Wiki for this part.

Gentoo Wiki: Binary package guide

Another interesting area for security was the rsync access of the GitHub actions to easily synchronize the packages with the builder. It's possible to restrict an SSH key to a single command to run, like a single rsync with no room to change a single parameter. Unfortunately, the setup requires using rsync in two different cases: downloading and pushing files, so I had to write a wrapper looking at the variable SSH_COMMAND and allowing either the "pull" rsync, or the "push" rsync.

Restrict rsync command over SSH

7. Conclusion §

The GitHub free plan allows you to run a builder 24/7 (with no parallel execution), it's really fast enough to keep a non-desktop @world up to date. If you have a pro account, the local cache GitHub cache may not be limited, and you may be able to keep the built packages there, removing the "pull packages" step.

If you really want to use this, I'd recommend using a schedule in the GitHub action to run it every day. It's as simple as adding this in the GitHub workflow.

on:
  schedule:
   - cron: '0 2 * * *'  # every day at 02h00

8. Credits §

I would like to thank Jonathan Tremesaygues who wrote most of the GitHub actions pieces after I shared with him about my idea and how I would implement it.

Jonathan Tremesaygues's website

9. Going further §

Here is a simple script I'm using to use a local Linux machine as a Gentoo builder for the box you run it from. It's using a gentoo stage3 docker image, populated with packages from the local system and its /etc/portage/ directory.

Note that you have to use app-misc/resolve-march-native to generate the compiler command line parameters to replace -march=native because you want the remote host to build with the correct flags and not its own -march=native, you should also make sure those flags are working on the remote system. From my experience, any remote builder newer than your machine should be compatible.

Tildegit: Example of scripts to build packages on a remote machine for the local machine

Lightweight data monitoring using RRDtool

Written by Solène, on 16 February 2023.
Tags: #monitoring #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

I like my servers to run the least code possible, and the least services running in general, this ease maintenance and let room for other thing to run. I recently wrote about monitoring software to gather metrics and render them, but they are all overkill if you just want to keep track of a single value over time, and graph it for visualization.

Fortunately, we have an old and robust tool doing the job fine, it's perfectly documented and called RRDtool.

RRDtool official website

RRDtool stands for "Round Robin Database Tool", it's a set of programs and a specific file format to gather metrics. The trick with RRD files is that they have a fixed size, when you create it, you need to define how many values you want to store in it, at which frequency, for how long. This can't be changed after the file creation.

In addition, RRD files allow you to create derivated time series to keep track of computed values on a longer timespan, but with a lesser resolution. Think of the following use case: you want to monitor your home temperature every 10 minutes for the past 48 hours, but you want to keep track of some information for the past year, you can tell RRD to compute the average temperature for every hour, but for a week, or the average temperature for four hours but for a month, and the average temperature per day for a year. All of this will be fixed size.

2. Anatomy of a RRD file §

RRD files can be dumped as XML, this will give you a glimpse that may ease the understanding of this special file format.

Let's create a file to monitor the battery level of your computer every 20 seconds, with the last 5 values, don't focus at understanding the whole command line now:

rrdtool create test.rrd --step 10 DS:battery:GAUGE:20:0:100 RRA:AVERAGE:0.5:1:5

If we dump the created file using the according command, we get this result (stripped a bit to make it fit better):

<!-- Round Robin Database Dump -->
<rrd>
	<version>0003</version>
	<step>10</step> <!-- Seconds -->
	<lastupdate>1676569107</lastupdate> <!-- 2023-02-16 18:38:27 CET -->

	<ds>
		<name> battery </name>
		<type> GAUGE </type>
		<minimal_heartbeat>20</minimal_heartbeat>
		<min>0.0000000000e+00</min>
		<max>1.0000000000e+02</max>
		<!-- PDP Status -->
		<last_ds>U</last_ds> <value>NaN</value> <unknown_sec> 7 </unknown_sec>
	</ds>

	<!-- Round Robin Archives -->
	<rra>
		<cf>AVERAGE</cf>
		<pdp_per_row>1</pdp_per_row> <!-- 10 seconds -->

		<params> <xff>5.0000000000e-01</xff> </params>
		<cdp_prep>
			<ds>
			<primary_value>0.0000000000e+00</primary_value>
			<secondary_value>0.0000000000e+00</secondary_value>
			<value>NaN</value>
			<unknown_datapoints>0</unknown_datapoints>
			</ds>
		</cdp_prep>
		<database>
			<!-- 2023-02-16 18:37:40 CET / 1676569060 --> <row><v>NaN</v></row>
			<!-- 2023-02-16 18:37:50 CET / 1676569070 --> <row><v>NaN</v></row>
			<!-- 2023-02-16 18:38:00 CET / 1676569080 --> <row><v>NaN</v></row>
			<!-- 2023-02-16 18:38:10 CET / 1676569090 --> <row><v>NaN</v></row>
			<!-- 2023-02-16 18:38:20 CET / 1676569100 --> <row><v>NaN</v></row>
		</database>
	</rra>
</rrd>

The most important thing to understand here, is that we have a "ds" (data serie) named battery of type GAUGE with no last value (I never updated it), but also a "RRA" (Round Robin Archive) for our average value that contain timestamp and no value associated to each. You can see that internally, we already have our 5 slots that exist with a null value associated. If I update the file, the first null value will disappear, and a new record will be added at the end with the actual value.

3. Monitoring a value §

In this guide, I would like to share my experience at using rrdtool to monitor my solar panel power output over the last few hours, which can be easily displayed on my local dashboard. The data are also collected and sent to a graphana server, but it's not local and displaying to know the last values is wasting resources and bandwidth.

First, you need rrdtool to be installed, you don't need anything else to work with RRD files.

3.1. Create the RRD file §

Creating the RRD file is the most tricky part, because you can't change it afterward.

I want to collect a data every 5 minutes (300 seconds), this is an absolute data between 0 and 4000, so we will define a step of 300 seconds to tell the file must receive a value every 300 seconds. The type of the value will be GAUGE, because it's just a value that doesn't depend on the previous one. If we were monitoring power change over time, we would like to use DERIVE, because it computes the delta between each value.

Furthermore, we need to configure the file to give up on a value slot if it's not updated within 600 seconds.

Finally, we want to be able to graph each measurement, this can be done by adding an AVERAGE calculated value in the file, but with a resolution of 1 value, with 240 measurements stored. What this mean, is for each time we add a value in the RRD file, the field for AVERAGE will be calculated with only the last value as input, and we will keep 240 of them, allowing us to graph up to 240 * 5 minutes of data back in time.

rrdtool create solar-power.rrd --step 300 ds:value:gauge:600:0:4000   rra:average:0.5:1:240
                                               ^    ^     ^  ^  ^            ^     ^  ^  ^
                                               |    |     |  |  | max value  |     |  |  | number of values to keep
                                               |    |     |  | min value     |     |  | how many previous values should be used in the function, 1 means just a single value, so averaging itself
                                               |    |     | time before null |     | (xfiles factor) how much percent of unknown values do we agree to use for calculating a value
                                               |    | measurement type       | function to apply, can be AVERAGE, MAX, MIN, LAST, or mathematical operations
                                               | variable name

And then, you have your solar-power.rrd file created. You can inspect it with rrdtool info solar-power.rrd or dump its content with rrdtool dump solar-power.rrd.

RRDtool create documentation

3.2. Add values to the RRD file §

Now that we have prepared the file to receive data, we need to populate it with something useful. This can be done using the command rrdtool update.

CURRENT_POWER=$(some-command-returning-a-value)
rrdtool update solar-power.rrd "N:${CURRENT_POWER}"
                                ^    ^
                                |    | value of the first field of the RRD file (we created a single field)
                                | when the value has been measured, N equals to NOW

RRDtool update documentation

3.3. Graph the content of the RRD file §

The trickiest part, but less problematic, is to generate a usable graph from the data. The operation is not destructive as it's not modifying the file, so we can make a lot of experimentations on it without affecting the content.

We will generate something simple like the picture below. Of course, you can add a lot more information, color, axis, legends etc.. but I need my dashboard to stay simple and clean.

A diagram displaying solar power over time (on a cloudy day)
A diagram displaying solar power over time (on a cloudy day)
rrdtool graph --end now -l 0 --start end-14000s --width 600 --height 300 \
    /var/www/htdocs/dashboard/solar.svg -a SVG \
    DEF:ds0=/var/lib/rrdtool/solar-power.rrd:value:AVERAGE \
    "LINE1:ds0#0000FF:power" \
    "GPRINT:ds0:LAST:current value %2.1lf"

I think most flags are explicit, if not you can look at the documentation, what interests us here are the last three lines.

The DEF line associates the RRA AVERAGE of the variable value in the file /var/lib/rrdtool/solar-power.rrd to the name ds0 that will be used later in the command line.

The LINE1 line associates a legend, and a color to the rendering of this variable.

The GPRINT line adds a text in the legend, here we are using the last value of ds0 and format it in a printf style string current value %2.1lf.

RRDtool graph documentation

RRDtool graph examples

4. Conclusion §

RRDtool is very nice, it's a storage engine for monitoring software such as collectd or munin, but we can also use them on the spot with simple scripts. However, they have drawbacks, when you start to create many files it doesn't scale well, generate a lot of I/O and consume CPU if you need to render hundreds of pictures, that's why a daemon named rrdcached has been created to help mitigate the load issue by delegating updates of a lot of RRD files in a more sequential way.

5. Going further §

I encourage you to look at the official project website, all the other command can be very useful, and rrdtool also exports data as XML or JSON if needed, which is perfect to plug in with other software.

Introduction to nftables on Linux

Written by Solène, on 06 February 2023.
Tags: #linux #firewall #nftables

Comments on Fediverse/Mastodon

1. Introduction §

Linux kernel has an integrated firewall named netfilter, but you manipulate it through command lines such as the good old iptables, or nftables which will eventually superseed iptables.

Today, I'll share my experience in using nftables to manage my Linux home router, and my workstation.

I won't explain much in this blog post because I just want to introduce nftables and show what it looks like, and how to get started.

I added comments in my configuration files, I hope it's enough to get a grasp and make you curious to learn about nftables if you use Linux.

2. Configurations §

nftables works by creating a file running nft -f in the shebang, this allows atomic replacement of the ruleset if it's valid.

Depending on your system, you may need to run the script at boot, but for instance on Gentoo, a systemd service is provided to save rules upon shutdown and restore them at boot.

2.1. Router §

#!/sbin/nft -f
flush ruleset

table inet filter {

    # defines a list of networks for further reference
    set safe_local {
	type ipv4_addr
	flags interval

	elements = { 10.42.42.0/24 }
    }

    chain input {
        # drop by default
        type filter hook input priority 0; policy drop;
        ct state invalid drop comment "early drop of invalid packets"

        # allow connections to work when initiated from this system
        ct state {established, related} accept comment "accept all connections related to connections made by us"

        # allow loopback
        iif lo accept comment "accept loopback"

        # remove weird packets
        iif != lo ip daddr 127.0.0.1/8 drop comment "drop connections to loopback not coming from loopback"
        iif != lo ip6 daddr ::1/128    drop comment "drop connections to loopback not coming from loopback"

        # make ICMP work
        ip protocol icmp accept comment "accept all ICMP types"
        ip6 nexthdr icmpv6 accept comment "accept all ICMP types"

        # only for known local networks
        ip saddr @safe_local tcp dport {22, 53, 80, 2222, 19999, 12344, 12345, 12346} accept
        ip saddr @safe_local udp dport {53} accept

        # allow on WAN
        iif eth0 tcp dport {80} accept
        iif eth0 udp dport {7495} accept
    }

    # allow NAT to get outside
    chain lan_masquerade {
        type nat hook postrouting priority srcnat;
        meta nfproto ipv4 oifname "eth0" masquerade
    }

    # port forwarding
    chain lan_nat {
        type nat hook prerouting priority dstnat;
        iif eth0 tcp dport 80 dnat ip to 10.42.42.102:8080
    }

}

2.2. Workstation §

#!/sbin/nft -f

flush ruleset

table inet filter {

    set safe_local {
	type ipv4_addr
	flags interval

	elements = { 10.42.42.0/24, 10.43.43.1/32 }
    }

    chain input {
        # drop by default
        type filter hook input priority 0; policy drop;
        ct state invalid drop comment "early drop of invalid packets"

        # allow connections to work when initiated from this system
        ct state {established, related} accept comment "accept all connections related to connections made by us"

        # allow loopback
        iif lo accept comment "accept loopback"

        # remove weird packets
        iif != lo ip daddr 127.0.0.1/8 drop comment "drop connections to loopback not coming from loopback"
        iif != lo ip6 daddr ::1/128    drop comment "drop connections to loopback not coming from loopback"

        # make ICMP work
        ip protocol icmp accept comment "accept all ICMP types"
        ip6 nexthdr icmpv6 accept comment "accept all ICMP types"

        # only for known local networks
        ip saddr @safe_local tcp dport 22 accept comment "accept SSH"
        ip saddr @safe_local tcp dport {7905, 7906} accept comment "accept musikcube"
        ip saddr @safe_local tcp dport 8080 accept comment "accept nginx"
        ip saddr @safe_local tcp dport 1714-1764 accept comment "accept kdeconnect TCP"
        ip saddr @safe_local udp dport 1714-1764 accept comment "accept kdeconnect UDP"
        ip saddr @safe_local tcp dport 22000 accept comment "accept syncthing"
        ip saddr @safe_local udp dport 22000 accept comment "accept syncthing"
        ip saddr @safe_local tcp dport {139, 775, 445} accept comment "accept samba"
        ip saddr @safe_local tcp dport {111, 775, 2049} accept comment "accept NFS TCP"
        ip saddr @safe_local udp dport 111 accept comment "accept NFS UDP"

        # for my public IP over VPN
        ip daddr 78.224.46.36 udp dport 57500-57600 accept comment "accept mosh"
        ip6 daddr 2a00:5854:2151::1 udp dport 57500-57600 accept comment "accept mosh"

    }

    # drop anything that looks forwarded
    chain forward {
        type filter hook forward priority 0; policy drop;
    }

}

3. Some commands §

If you need to operate a firewall using nftables, you may use nft to add/remove rules on the go instead of using the script with the ruleset.

However, let me share a small cheatsheet of useful commands:

3.1. List rules §

If you need to display the current rules in use:

nft list ruleset

3.2. Flush rules §

If you want to delete all the rules, just use:

nft flush ruleset

4. Going further §

If you want to learn more about nftables, there is the excellent man page of the command nft.

I used some resources from Arch Linux and Gentoo that you may also enjoy:

Gentoo Wiki: Nftables

Gentoo Wiki: Nftables examples

Arch Linux Wiki: Nftables

[Cheatsheet] Fossil version control software

Written by Solène, on 29 January 2023.
Tags: #fossil #versioning #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

Fossil is a DVCS (decentralized version control software), an alternative to programs such as darcs, mercurial or git. It's developed by the same people doing sqlite and rely on sqlite internally.

Fossil official website

2. Why? §

Why not? I like diversity in software, and I'm unhappy to see Git dominating the field. Fossil is a viable alternative, with simplified workflow that work very well for my use case.

One feature I really like is the autosync, when a remote is configured, fossil will automatically push the changes to the remote, then it looks like a centralizer version control software like SVN, but for my usage it's really practical. Of course, you can disable autosync if you don't want to use this feature. I suppose this could be reproduced in git using a post-commit hook that run git push.

Fossil is opinionated, so you may not like it if that doesn't match your workflow, but when it does, it's a very practical software that won't get in your way.

3. Fossil repository is a file §

A major and disappointing fact at first is that a fossil repository is a single file. In order to checkout the content of the repository, you will need to run fossil open /path/to/repo.fossil in the directory you want to extract the files.

Fossil supports multiple checkout of different branches in different directories, like git worktrees.

4. Cheatsheet §

Because I'm used to other versionning software, I need a simple cheatsheet to learn most operations, they are easy to learn, but I prefer to note it down somewhere.

4.1. View extra files §

You can easily find non-versioned files using the following command:

fossil extras

4.2. View changes §

You can get a list of tracked files that changed:

fossil changes

Note that it only display a list of files, not the diff that you can obtain using fossil diff.

4.3. Commit §

By default, fossil will commit all changes in tracked files, if you want to only commit a change in a file, you must pass it as a parameter.

fossil commit

4.4. Change author name §

fossil user new solene@t470 and fossil user default solene@t470

More possibilities are explained in Fossil documentation

4.5. Add a remote §

Copy the .fossil file to a remote server (I'm using ssh), and in your fossil checkout, type fossil remote add my-remote ssh://hostname//home/solene/my-file.fossil, and then fossil remote my-remote.

Note that the remote server must have the fossil binary available in $PATH.

4.6. Display the Web Interface §

fossil ui will open your web browser and log in as admin user, you can view the timeline, bug trackers, wiki, forum etc... Of course, you can enable/disable everything you want.

4.7. Get changes from a remote §

This is a two-step operation, you must first get changes from the remote fossil, and then update your local checkout:

fossil pull
fossil update

4.8. Commit partial changes in a file §

Fossil doesn't allow staging and committing partial changes in a file like with git add -p, the official way is to stash your changes, generate a diff of the stash, edit the diff, apply it and commit. It's recommended to use a program named patchouli to select hunks in the diff file to ease the process.

Fossil documentation: Git to Fossil translation

The process looks like this:

fossil stash -m "tidying for making atomic commits"
fossil stash diff > diff
$EDITOR diff
patch -p0 < diff
fossil commit

Note that if you added new files, the "add" information is stashed and contained in the diff.

Configure syncthing to sync a single file

Written by Solène, on 28 January 2023.
Tags: #linux #syncthing #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

Quick blog entry to remember about something that wasn't as trivial as I thought. I needed to use syncthing to keep a single file in sync (KeePassXC database) without synchronizing the whole directory.

You have to use mask exclusion feature to make it possible. Put it simple, you need the share to forbid every file, except the one you want to sync.

This configuration happens in the .stignore file in the synchronized directory, but can also be managed from the Web interface.

Syncthing documentation about ignoring files

2. Example §

If I want to only sync KeePassXC files (they have the .kdbx extension), I have this in my .stignore file:

!*.kdbx
*

And that's all!

Note that this must be set on all nodes using this share, otherwise you may have surprises.

How to boot on a BTRFS snapshot

Written by Solène, on 04 January 2023.
Tags: #linux #gentoo #btrfs

Comments on Fediverse/Mastodon

1. Introduction §

I always wanted to have a simple rollback method on Linux systems, NixOS gave me a full featured one, but it wasn't easy to find a solution for other distributions.

Fortunately, with BTRFS, it's really simple thanks to snapshots being mountable volumes.

2. Setup §

You need a Linux system with a BTRFS filesystem, in my examples, the root subvolume (where / is) is named gentoo.

I use btrbk to make snapshots of / directly in /.snapshots, using the following configuration file:

snapshot_preserve_min   30d
volume /
  snapshot_dir .snapshots
    subvolume .

With a systemd service, it's running once a day, so I'll have for 30 days of snapshots to restore my system if needed.

This creates snapshots named like the following:

$ ls /.snapshots/
ROOT.20230102
ROOT.20230103
ROOT.20230104

A snapshot address from BTRFS point of view looks like gentoo/.snapshots/ROOT.20230102.

I like btrbk because it's easy to use and configure, and it creates easy to remember snapshots names.

3. Booting on a snapshot §

When you are in the bootloader (GRUB, systemd-boot, Lilo etc..), edit the command line, and add the new option (replace if already exists) with the following, the example uses the snapshot ROOT.20230102:

rootflags=subvol=gentoo/.snapshots/ROOT.20230103

Boot with the new command line, and you should be on your snapshot as the root filesystem.

4. Be careful §

When you are on a snapshot, this mean any change will be specific to this volume.

If you use a separate partition for /boot, an older snapshot may not have the kernel (or its module) you are trying to boot.

5. Conclusion §

This is a very simple but effective mecanism, more than enough to recover from a bad upgrade, especially when you need the computer right now.

6. Going further §

There is a project grub-btrfs which can help you adding BTRFS snapshots as boot choices in GRUB menus.

grub-btrfs GitHub project page

Booting Gentoo on a BTRFS from multiple LUKS devices

Written by Solène, on 02 January 2023.
Tags: #linux #gentoo #btrfs

Comments on Fediverse/Mastodon

1. Introduction §

This is mostly a reminder for myself. I installed Gentoo on a machine, but I reused the same BTRFS filesystem where NixOS is already installed, the trick is the BTRFS filesystem is composed of two partitions (a bit like raid 0) but they are from two different LUKS partitions.

It wasn't straightforward to unlock that thing at boot.

2. Fix grub error §

Grub was trying to autodetect the root partition to add root=/dev/something, but as my root filesystem requires /dev/mapper/ssd1 and /dev/mapper/ssd2, it was simply adding root=/dev/mapper/ssd1 /dev/mapper/ssd2, which is wrong.

This required a change in the file /etc/grub.d/10_linux where I entirely deleted the root= parameter.

3. Compile systemd with cryptsetup §

A mistake I made was to try to boot without systemd compiled with cryptsetup support, this was just failing because in the initramfs, some systemd services were used to unlock the partitions, but without proper support for cryptsetup it didn't work.

4. Linux command line parameters §

In /etc/default/grub, I added this line, it contains the UUID of both LUKS partitions needed, and a root=/dev/dm-0 which is unexpectedly the first unlocked device path, and rd.luks=1 to enble LUKS support.

GRUB_CMDLINE_LINUX="rd.luks.uuid=24682f88-9115-4a8d-81fb-a03ec61d870b rd.luks.uuid=1815e7a4-532f-4a6d-a5c6-370797ef2450 rootfs=btrfs root=/dev/dm-0 rd.luks=1"

5. Run Dracut and grub §

After the changes, I did run dracut --force --kver 5.15.85-gentoo-dist and grub-mkconfig -o /boot/grub/grub.cfg

6. Conclusion §

It's working fine now, I thought it would require me to write a custom initrd script, but dracut is providing all I needed, but there were many quirks on the path with no really helpful message to understand what's failing.

Now, I can enjoy my dual boot Gentoo / NixOS (they are quite antagonists :D), but they share the same filesystem and I really enjoy this weird setup.

Export Flatpak programs from a computer to another

Written by Solène, on 01 January 2023.
Tags: #linux #flatpak #bandwidth

Comments on Fediverse/Mastodon

1. Introduction §

As a flatpak user, but also someone with a slow internet connection, I was looking for a way to export a flatpak program to install it on another computer. It turns out flatpak supports this, but it's called "create-usb" for some reasons.

So today, I'll show how to export a flatpak program from a computer to another.

Flatpak official website

Flatpak documentation about usb drives

2. Pre-requisites §

For some reasons, the default flathub parameters doesn't associate it a "Collection ID", which is required for the create-usb feature to work, so we need to associate a "Collection ID" to the flathub remote repository on both systems.

We can use the example from the official documentation:

flatpak remote-modify --collection-id=org.flathub.Stable flathub

3. Export §

The export process is simple, create a directory in which you want the flatpak application to be exported, we will use ~/export/ in the examples, with the program org.mozilla.firefox.

flatpak create-usb ~/export/ org.mozilla.firefox

The export process will display a few lines and tell you when it finished.

If you export multiple programs into the same directory, the export process will be smart and skip already existing components.

4. Import §

Take the ~/export/ directory, either on a USB drive, or copy it using rsync, share it over NFS/Samba etc... It's up to you. In the example, ~/export/ refers to the same directory transferred from the previous step onto the new system.

Now, we can run the import command to install the program.

flatpak install --sideload=~/export/.ostree/repo/ flathub org.mozilla.firefox

If it's working correctly, it should be very fast.

5. Limitation §

Because the flatpak components/dependencies of a program can differ depending on the host (for example if you have an NVIDIA card, it will pull some NVIDIA dependencies), so if you export a program from a non-NVIDIA system to the other, it won't be complete to work reliably on the new system, but the missing parts can be downloaded on the Internet, it's still reducing the bandwidth requirement.

6. Conclusion §

I kinda like Flatpak, it's convenient and reliable, and allow handling installed programs without privileges escalation. The programs can be big, it's cool to be able to save/export them for later use.

Authentication gateway with SSH on OpenBSD

Written by Solène, on 01 December 2022.
Tags: #openbsd #security #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

A neat feature in OpenBSD is the program authpf, an authenticating gateway using SSH.

Basically, it allows to dynamically configure the local firewall PF by connecting/disconnecting into a user account over SSH, either to toggle an IP into a table or rules through a PF anchor.

2. Use case §

This program is very useful for the following use case:

  • firewall rules dedicated to authenticated users
  • enabling NAT to authenticated users
  • using a different bandwidth queue for authenticated users
  • logging, or not logging network packets of authenticated users

Of course, you can be creative and imagine other use cases.

This method is actually different from using a VPN, it doesn't have encryption extra cost but is less secure in the sense it only authenticates an IP or username, so if you use it over the Internet, the triggered rule may also benefit to people using the same IP as yours. However, it's much simpler to set up because users only have to share their public SSH key, while setting up a VPN is another level of complexity and troubleshooting.

3. Example setup §

In the following example, you manage a small office OpenBSD router, but you only want Chloe's workstation to reach the Internet with the NAT. We need to create her a dedicated account, set the shell to authpf, deploy her SSH key and configure PF.

# useradd -m -s /usr/sbin/authpf chloe
# echo "$ssh_key" >> ~chloe/.ssh/authorized_keys
# touch /etc/authpf/authpf.conf /etc/authpf/authpf/rules

Now, you can edit /etc/pf.conf and use the default table name authpf_users. With the following PF snippet, we will only allow authenticated users to go through the NAT.

table <authpf_users> persist
match out on egress inet from <authpf_users> to any nat-to (egress)

Reload your firewall, and when Chloe will connect, she will be able to go through the NAT.

4. Conclusion §

The program authpf is an efficient tool for the network administrator's toolbox. And with the use of PF anchors, you can really extend its potential as you want, it's really not limited to tables.

5. Going further §

The man page contains a lot of extra information for customization, you should definitely read it if you plan to use authpf.

OpenBSD man page of authpf(8)

5.1. Blocking users §

It's possible to ban users, for various reasons you may want to block someone with a message asking to reach the help desk. This can be done by creating a file name after the username, like in the following example for user chloe: /etc/authpf/banned/chloe, the file text content will be displayed to the user upon connection.

5.2. Greeeting message §

It's possible to write a custom greeting message displayed upon connection, this can be global or per user, just write a message in /etc/authpf/authpf.message for a global one, or /etc/authpf/users/chloe/authpf.message for user chloe.

Automatic prompt to unlock remote encrypted partitions

Written by Solène, on 20 November 2022.
Tags: #openbsd #security #networking #ssh #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

I have remote systems that only have /home as encrypted partitions, the reason is it ease a lot of remote management without a serial access, it's not ideal if you have critical files but in my use case, it's good enough.

In this blog post, I'll explain how to get the remote system to prompt you the unlocking passphrase automatically when it boots. I'm using OpenBSD in my example, but you can achieve the same with Linux and cryptsetup (LUKS), if you want to push the idea on Linux, you could do this from the initramfs to unlock your root partition.

2. Requirement §

  • OpenBSD
  • a non-root encrypted partition
  • a workstation with ssh that is reachable by the remote server (VPN, NAT etc…)

3. Setup §

  1. install the package zenity on your workstation
  2. on the remote system generate ssh-keys without a passphrase on your root account using ssh-keygen
  3. copy the content of /root/.ssh/id_rsa.pub for the next step (or the public key file if you chose a different key algorithm)
  4. edit ~/.ssh/authorized_keys on your workstation
  5. create a new line with: restrict,command="/usr/local/bin/zenity --forms --text='Unlock t400 /home' --add-password='passphrase' --display=:0" $THE_PUBLIC_KEY_HERE

The new line allows the ssh key to connect to our local user, but it gets restricted to a single command: zenity, which is a GUI dialog program used to generate forms/dialogs in X sessions.

In the example, this creates a simple form in an X window with a label "Unlock t400 /home" and add a field password hiding typed text, and showing it on display :0 (the default one). Upon connection from the remote server, the form is displayed, you can type in and validate, then the content is passed to stdout on the remote server, to the command bioctl which unlocks the disk.

On the server, creates the file /etc/rc.local with the following content (please adapt to your system):

#!/bin/sh

ssh solene@10.42.42.102 | bioctl -s -c C -l 1a52f9ec20246135.k softraid0
if [ $? -eq 0 ]
then
    mount /home
fi

In this script, solene@10.42.42.102 is my user@laptop-address, and 1a52f9ec20246135.k is my encrypted partition. The file /etc/rc.local is run at boot after most of the services, including networking.

You should get a display like this when the system boots:

a GUI window asking for a passphrase to unlock the /home partition of the computer named T400
a GUI window asking for a passphrase to unlock the /home partition of the computer named T400

4. Conclusion §

With this simple setup, I can reboot my remote systems and wait for the passphrase to be asked quite reliably. Because of ssh, I can authenticate which system is asking for a passphrase, and it's sent encrypted over the network.

It's possible to get more in depth in this idea by using a local password database to automatically pick the passphrase, but you lose some kind of manual control, if someone steals a machine you may not want to unlock it after all ;) It would also be possible to prompt a Yes/No dialog before piping the passphrase from your computer, do what feels correct for you.

Pinafore: a light Mastodon web client

Written by Solène, on 18 November 2022.
Tags: #mastodon #selfhosting

Comments on Fediverse/Mastodon

1. Intro §

This blog post is for Mastodon users who may not like the official Mastodon web interface. It has a lot of features, but it's using a lot of CPU and requires a large screen.

Fortunately, there are alternatives front-ends to Mastodon, this is possible through calls between the front-end to then instance API. I would like to introduce you Pinafore.

Pinafore GitHub client

Pinafore.social website

2. What's Pinafore? §

Pinafore is a "web application" consisting of a static website, this implies nothing is actually store on the server hosting Pinafore, think about it like a page loaded in your browser that stores data in your browser and make API calls from your browser.

This design is elegant because it delegates everything to the browser and requires absolutely no processing on the Pinafore hosting server, it's just a web server there serving static files once.

As I said previously, Pinafore is a Mastodon (but also extends to other Fediverse instances whenever possible) front-end with a bunch of features such as:

- accessibility (for content warning content, greyscale mode, contrast, key bindings)

- only one column, it's really compact

- simple design, fast to load and doesn't eat much CPU (especially compared to official Mastodon interface)

- read-only support if you visit your Pinafore host when not connected, I find this very useful (remember that cache is stored in your browser)

- can handle multiple accounts at once

This being said, Pinafore doesn't target minimalism either, it needs javascript and a modern web browser.

3. How to use Pinafore? §

There are two ways to use it, either by using the official hosted service, or by hosting it yourself.

Whether you choose the official or self-hosted, the principle is the following: you enter your account instance address in it the first time, this will trigger an oauth authentication on your instance and will ask if you want pinafore to use your account through the API (this can be revoked later from your Mastodon account). Accept, and that's it!

3.1. Pinafore.social §

The official service is run by the developers and kept up to date. You can use it without installing anything, simply visit the address below and go through the login process.

Pinafore.social website

This is a very convenient way to use pinafore, but it comes with a tradeoff: it involves a third party between your social network account and your client. While pinafore.social is trustable, this doesn't mean it can't be compromised and act as a "Man In The Middle". As I mentionned earlier, no data are stored by Pinafore because everything is in your browser, but nothing prevent a malicious attacker to modify the hosted Pinafore code to redirect data from your browser to a remote server they control in order to steal information.

3.2. Self Hosting §

It's possible to create Pinafore static files from your system and host it on any web server. While it's more secure than pinafore.social (if your host is secure), it still involves extra code that could "potentially" be compromised through a rogue commit, but it's not realistic to encounter this case when using Pinafore releases versions.

For this step, I'll link to the according documentation in the project:

Exporting Pinafore

4. Trivia §

Pinafore is the recommended web front-end for the Mastodon server implementation GoToSocial which only provide a backend.

GoToSocial GitHub project page

Hard user separation with two NixOS as one

Written by Solène, on 17 November 2022.
Tags: #nixos #security

Comments on Fediverse/Mastodon

1. Credits §

This blog post is a republication of the article I published on my employer's blog under CC BY 4.0. I'm grateful to be allowed to publish NixOS related content there, but also to be able to reuse it here!

License CC by 4.0

Original publication place: Hard user separation with NixOS

2. Introduction §

This guide explains how to install NixOS on a computer, with a twist.

If you use the same computer in different contexts, let's say for work and for your private life, you may wish to install two different operating systems to protect your private life data from mistakes or hacks from your work. For instance a cryptolocker you got from a compromised work email won't lock out your family photos.

But then you have two different operating systems to manage, and you may consider that it's not worth the effort and simply use the same operating system for your private life and for work, at the cost of the security you desired.

I offer you a third alternative, a single NixOS managing two securely separated contexts. You choose your context at boot time, and you can configure both context from either of them.

You can safely use the same machine at work with your home directory and confidential documents, and you can get into your personal context with your private data by doing a reboot. Compared to a dual boot system, you have the benefits of a single system to manage and no duplicated package.

For this guide, you need a system either physical or virtual that is supported by NixOS, and some knowledge like using a command line. You don't necessarily need to understand all the commands. The system disk will be erased during the process.

You can find an example of NixOS configuration files to help you understand the structure of the setup on the following GitHub repository:

tweag/nixos-specialisation-dual-boot GitHub repository

3. Disks §

Here is a diagram showing the whole setup and the partitioning.

Picture showing a diagram of disks and partitions
Picture showing a diagram of disks and partitions

3.1. Partitioning §

We will create a 512 MB space for the /boot partition that will contain the kernels, and allocate the space left for an LVM partition we can split later.

parted /dev/sda -- mklabel gpt
parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
parted /dev/sda -- mkpart primary 512MiB 100%
parted /dev/sda -- mkpart set 1 esp on

Note that these instructions are valid for UEFI systems, for older systems you can refer to the NixOS manual to create a MBR partition.

NixOS manual: disks and partitioning.

3.2. Create LVM volumes §

We will use LVM so we need to initialize the partition and create a Volume Group with all the free space.

pvcreate /dev/sda2
vgcreate pool /dev/sda2

We will then create three logical volumes, one for the store and two for our environments:

lvcreate -L 15G -n root-private pool
lvcreate -L 15G -n root-work pool
lvcreate -l 100%FREE -n nix-store pool

NOTE: The sizes to assign to each volume is up to you, the nix store should have at least 30GB for a system with graphical sessions. LVM allows you to keep free space in your volume group so you can increase your volumes size later when needed.

3.3. Encryption §

We will enable encryption for the three volumes, but we want the nix-store partition to be unlockable with either of the keys used for the two root partitions. This way, you don't have to type two passphrases at boot.

cryptsetup luksFormat /dev/pool/root-work
cryptsetup luksFormat /dev/pool/root-private
cryptsetup luksFormat /dev/pool/nix-store # same password as work
cryptsetup luksAddKey /dev/pool/nix-store # same password as private

We unlock our partitions to be able to format and mount them. Which passphrase is used to unlock the nix-store doesn't matter.

cryptsetup luksOpen /dev/pool/root-work crypto-work
cryptsetup luksOpen /dev/pool/root-private crypto-private
cryptsetup luksOpen /dev/pool/nix-store nix-store

Please note we don't encrypt the boot partition, which is the default on most encrypted Linux setup. While this could be achieved, this adds complexity that I don't want to cover in this guide.

Note: the nix-store partition isn't called crypto-nix-store because we want the nix-store partition to be unlocked after the root partition to reuse the password. The code generating the ramdisk takes the unlocked partitions' names in alphabetical order, by removing the prefix crypto the partition will always be after the root partitions.

3.4. Formatting §

We format each partition using ext4, a performant file-system which doesn't require maintenance. You can use other filesystems, like xfs or btrfs, if you need features specific to them.

mkfs.ext4 /dev/mapper/crypto-work
mkfs.ext4 /dev/mapper/crypto-private
mkfs.ext4 /dev/mapper/nix-store

3.5. The boot partition §

The boot partition should be formatted using fat32 when using UEFI with mkfs.fat -F 32 /dev/sda1. It can be formatted in ext4 if you are using legacy boot (MBR).

4. Preparing the system §

Mount the partitions onto /mnt and its subdirectories to prepare for the installer.

mount /dev/mapper/crypto-work /mnt
mkdir -p /mnt/etc/nixos /mnt/boot /mnt/nix
mount /dev/mapper/nix-store /mnt/nix
mkdir /mnt/nix/config
mount --bind /mnt/nix/config /mnt/etc/nixos
mount /dev/sda1 /mnt/boot

We generate a configuration file:

nixos-generate-config --root /mnt

Edit /mnt/etc/nixos/hardware-configuration.nix to change the following parts:

fileSystems."/" =
  { device = "/dev/disk/by-uuid/xxxxxxx-something";
    fsType = "ext4";
  };

boot.initrd.luks.devices."crypto-work" = "/dev/disk/by-uuid/xxxxxx-something";

by

fileSystems."/" =
  { device = "/dev/mapper/crypto-work";
    fsType = "ext4";
  };

boot.initrd.luks.devices."crypto-work" = "/dev/pool/root-work";

We need two configuration files to describe our two environments, we will use hardware-configuration.nix as a template and apply changes to it.

sed '/imports =/,+3d' /mnt/etc/nixos/hardware-configuration.nix > /mnt/etc/nixos/work.nix
sed '/imports =/,+3d ; s/-work/-private/g' /mnt/etc/nixos/hardware-configuration.nix > /mnt/etc/nixos/private.nix
rm /mnt/etc/nixos/hardware-configuration.nix

Edit /mnt/etc/nixos/configuration.nix to make the imports code at the top of the file look like this:

imports =
  [
    ./work.nix
    ./private.nix
  ];

Remember we removed the file /mnt/etc/nixos/hardware-configuration.nix so it shouldn't be imported anymore.

Now we need to hook each configuration to become a different boot entry, using the NixOS feature called specialisation. We will make the environment you want to be the default in the boot entry as a non-specialised environment and non-inherited so it's not picked up by the other, and a specialisation for the other environment.

For the hardware configuration files, we need to wrap them with some code to create a specialisation, and the "non-specialisation" case that won't propagate to the other specialisations.

Starting from a file looking like this, some code must be added at the top and bottom of the files depending on if you want it to be the default context or not.

Content of an example file:

{ config, pkgs, modulesPath, ... }:
{
  boot.initrd.availableKernelModules = ["ata_generic" "uhci_hcd" "ehci_pci" "ahci" "usb_storage" "sd_mod"];
  boot.initrd.kernelModules = ["dm-snapshot"];
  boot.kernelModules = ["kvm-intel"];
  boot.extraModulePackages = [];

  fileSystems."/" = {
    device = "/dev/mapper/crypto-private";
    fsType = "ext4";
  };

  ---8<-----
  [more code here]
  ---8<-----

  swapDevices = [];
  networking.useDHCP = lib.mkDefault true;
  hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
}

Example result of the default context:

GitHub example ifle

({ lib, config, pkgs, ...}: {
  config = lib.mkIf (config.specialisation != {}) {

    boot.initrd.availableKernelModules = ["ata_generic" "uhci_hcd" "ehci_pci" "ahci" "usb_storage" "sd_mod"];
    boot.initrd.kernelModules = ["dm-snapshot"];
    boot.kernelModules = ["kvm-intel"];
    boot.extraModulePackages = [];

    fileSystems."/" = {
      device = "/dev/mapper/crypto-private";
      fsType = "ext4";
    };

    ---8<-----
    [more code here]
    ---8<-----

    swapDevices = [];
    networking.useDHCP = lib.mkDefault true;
    hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;

  };
})

Note the extra leading ( character that must also be added at the very beginning.

Example result for a specialisation named work

GitHub example file

{ config, lib, pkgs, modulesPath, ... }:
{
  specialisation = {
  work.configuration = {
  system.nixos.tags = [ "work" ];

    boot.initrd.availableKernelModules = ["ata_generic" "uhci_hcd" "ehci_pci" "ahci" "usb_storage" "sd_mod"];
    boot.initrd.kernelModules = ["dm-snapshot"];
    boot.kernelModules = ["kvm-intel"];
    boot.extraModulePackages = [];

    fileSystems."/" = {
      device = "/dev/mapper/crypto-work";
      fsType = "ext4";
    };

    ---8<-----
    [more code here]
    ---8<-----

    swapDevices = [];
    networking.useDHCP = lib.mkDefault true;
    hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
  };
  };
}

5. System configuration §

It's now the time to configure your system as you want. The file /mnt/etc/nixos/configuration.nix contains shared configuration, this is the right place to define your user, shared packages, network and services.

The files /mnt/etc/nixos/private.nix and /mnt/etc/nixos/work.nix can be used to define context specific configuration.

5.1. LVM Workaround §

During the numerous installation tests I've made to validate this guide, on some hardware I noticed an issue with LVM detection, add this line to your global configuration file to be sure your disks will be detected at boot.

    boot.initrd.preLVMCommands = "lvm vgchange -ay";

6. Installation §

6.1. First installation §

The partitions are mounted and you configured your system as you want it, we can run the NixOS installer.

nixos-install

Wait for the copy process to complete after which you will be prompted for the root password of the current crypto-work environment (or the one you mounted here), you also need to define the password for your user now by chrooting into your NixOS system.

# nixos-enter --root /mnt -c "passwd your_user"
New password:
Retape new password:
passwd: password updated successfully
# umount -R /mnt

From now, you have a password set for root and your user for the crypto-work environment, but no password are defined in the crypto-private environment.

6.2. Second installation §

We will rerun the installation process with the other environment mounted:

mount /dev/mapper/crypto-private  /mnt
mkdir -p /mnt/etc/nixos /mnt/boot /mnt/nix

mount /dev/mapper/nix-store /mnt/nix
mount --bind /mnt/nix/config /mnt/etc/nixos
mount /dev/sda1 /mnt/boot

As the NixOS configuration is already done and is shared between the two environments, just run nixos-install, wait for the root password to be prompted, apply the same chroot sequence to set a password to your user in this environment.

You can reboot, you will have a default boot entry for the default chosen environment, and the other environment boot entry, both requiring their own passphrase to be used.

Now, you can apply changes to your NixOS system using nixos-rebuild from both work and private environments.

7. Conclusion §

Congratulations for going through this long installation process. You can now log in to your two contexts and use them independently, and you can configure them by applying changes to the corresponding files in /etc/nixos/.

8. Going further §

8.1. Swap and hibernation §

With this setup, I chose to not cover swap space because this would allow to leak secrets between the contexts. If you need some swap, you will have to create a file on the root partition of your current context, and add the according code to the context filesystems.

If you want to use hibernation in which the system stops after dumping its memory into the swap file, your swap size must be larger than the memory available on the system.

It's possible to have a single swap for both contexts by using a random encryption at boot for the swap space, but this breaks hibernation as you can't unlock the swap to resume the system.

8.2. Declare users' passwords §

As you noticed, you had to run passwd in both contexts to define your user password and root's password. It is possible to define their password declaratively in the configuration file, refers to the documentation ofusers.mutableUsers and users.extraUsers.<name>.initialHashedPassword

for more information.

8.3. Rescue the installation §

If something is wrong when you boot the first time, you can reuse the installer to make changes to your installation: you can run again the cryptsetup luksOpen and mount commands to get access to your filesystems, then you can edit your configuration files and run

nixos-install again.

Mirroring sources used in nixpkgs (software preservation)

Written by Solène, on 03 November 2022.
Tags: #nix #life

Comments on Fediverse/Mastodon

1. Introduction §

This may appear like a very niche use case, in my quest of software conservancy for nixpkgs I didn't encounter many people understanding why I was doing this.

I would like to present you a project I made to easily download all the sources files required to build packages from nixpkgs, allowing to keep offline copies.

Why would you like to keep a local copy? If upstream disappear, you can't get access to the sources anymore, except maybe in Hydra, but you rely on a third party to access the sources, so it's still valuable to have local copies of software you care about, just to make copies. It's not that absolutely useful for everyone, but it's always important to have such tools available.

nixpkgs-mirror-tarballs project page

2. How to use it §

You must run it on a system with nix installed.

After cloning and 'cd-ing' into the directory, simply run ./run.sh some package list | ./mirror.pl. The command run.sh will generate a JSON structure containing all the dependencies used by the packages listed as arguments, and the script mirror.pl will iterate over the JSON list and use nix's fetcher to gather the sources in the nix store, verifying the checksum on the go. This will create a directory distfiles containing symlinks to the sources files stored in the store.

The symlinks are very important as they will prevent garbage collection from the store, and it's also used internally to quickly check if a file is already in the store.

To delete a file from the store, remove its symlink and run the garbage collector.

3. Limitation §

I still need to figure how to get a full list of all the packages, I currently have a work in progress relying on nix search --json but it doesn't work on 100% of the packages for some reasons.

It's currently not possible to easily trim distfiles that aren't useful anymore, I plan to maybe add it someday.

4. Trivia §

This task is natively supported in the OpenBSD tool building packages (dpb), it can fetch multiples files in parallel and automatic remove files that aren't used anymore. This was really complicated to figure how to replicate this with nixpkgs.

Nushell: Introduction to a new kind of shell

Written by Solène, on 31 October 2022.
Tags: #openbsd #nixos #nushell #shell

Comments on Fediverse/Mastodon

1. What is nushell §

Let me introduce you to a nice project I found while lurking on the Internet. It's called nushell and is a non-POSIX shell, so most of your regular shells knowledge (zsh, bash, ksh, etc…) can't be applied on it, and using it feels like doing functional programming.

It's a good tool for creating robust data manipulation pipelines, you can think of it like a mix of a shell which would include awk's power, behave like a SQL database, and which knows how to import/export XML/JSON/YAML/TOML natively.

You may want to try nushell only as a tool, and not as your main shell, it's perfectly fine.

With a regular shell, iterating over a command output can be complex when it involves spaces or newlines, for instance, that's why find and xargs have a -print0 parameter to have a special delimited between "items", but it doesn't compose well with other tools. Nushell handles correctly this situation as its manipulates the data using indexed entries, given you correctly parsed the input at the beginning.

Nushell official project page

Nushell documentation website

2. How to get it §

Nushell is a rust program, so it should work on every platform where Rust/Cargo are supported. I packaged it for OpenBSD, so it's available on -current (and will be in releases after 7.3 is out), the port could be used on 7.2 with no effort.

With Nix, it's packaged under the name nushell, the binary name is nu.

For other platforms, it's certainly already packaged, otherwise you can find installation instructions to build it from sources.

Nushell documentation: Building nushell from sources

3. Configuration §

At first run, you are prompted to use default configuration files, I'd recommend accepting, you will have files created in ~/.config/nushell/.

The only change I made from now is to make Tab completion case-sensitive, so D[TAB] completes to Downloads instead of asking between dev and Downloads. Look for case_sensitive_completions in .config/nushell/config.nu and set it to true.

4. Examples §

If you are like me, and you prefer learning by doing instead of reading a lot of documentation, I prepared a bunch of real world use case you can experiment with. The documentation is still required to learn the many commands and syntax, but examples are a nice introduction.

4.1. Getting help §

Help from nushell can be parsed directly with nu commands, it's important to understand where to find information about commands.

Use help a-command to learn from a single command:

> help help
Display help information about commands.

Usage:
  > help {flags} ...(rest) 

Flags:
  -h, --help - Display this help message
  -f, --find <String> - string to find in command names, usage, and search terms

[cut so it's not too long]

Use help commands to list all available commands (I'm limiting to 5 between there are a lot of commands)

help commands | last 5
╭───┬─────────────┬────────────────────────┬───────────┬───────────┬────────────┬───────────────────────────────────────────────────────────────────────────────────────┬──────────────╮
│ # │    name     │        category        │ is_plugin │ is_custom │ is_keyword │                                         usage                                         │ search_terms │
├───┼─────────────┼────────────────────────┼───────────┼───────────┼────────────┼───────────────────────────────────────────────────────────────────────────────────────┼──────────────┤
│ 0 │ window      │ filters                │ false     │ false     │ false      │ Creates a sliding window of `window_size` that slide by n rows/elements across input. │              │
│ 1 │ with-column │ dataframe or lazyframe │ false     │ false     │ false      │ Adds a series to the dataframe                                                        │              │
│ 2 │ with-env    │ env                    │ false     │ false     │ false      │ Runs a block with an environment variable set.                                        │              │
│ 3 │ wrap        │ filters                │ false     │ false     │ false      │ Wrap the value into a column.                                                         │              │
│ 4 │ zip         │ filters                │ false     │ false     │ false      │ Combine a stream with the input                                                       │              │
╰───┴─────────────┴────────────────────────┴───────────┴───────────┴────────────┴───────────────────────────────────────────────────────────────────────────────────────┴──────────────╯

Add sort-by category to list them... sorted by category.

help commands | sort-by category

Use where category == filters to only list commands from the filters category.

help commands | where category == filters

Use find foobar to return lines containing foobar.

help commands | find insert

4.2. General examples §

4.2.1. Converting a data structure into another §

This is just an example from YAML to JSON, but you can convert much more formats into other formats.

open dev/home-impermanence/tests/impermanence.yml | to json
{
  "directories":
  [
    "Documents",
    "Downloads",
    "Datastore/Music",
    "Datastore",
    "Datastore/",
    "Datastore/Music/Band1",
    ".config",
    "foo/bar",
    "foo/bar/hello"
  ],
  "size": "500m",
  "files":
  [
    ".Xdefaults",
    ".profile",
    ".xsession",
  ]
}

4.2.2. Parsing sysctl output §

sysctl -a | parse -r "(?<key>.*?)=(?<value>.*)"

Because the output would be too long, here is how you get 10 random keys from sysctl.

sysctl -a | parse -r "(?<key>.*?)=(?<value>.*)" | shuffle | last 10 | sort-by key
╭───┬─────────────────────────────────────────────────┬──────────╮
│ # │                       key                       │  value   │
├───┼─────────────────────────────────────────────────┼──────────┤
│ 0 │ fs.quota.reads                                  │  0       │
│ 1 │ net.core.high_order_alloc_disable               │  0       │
│ 2 │ net.ipv4.conf.all.drop_gratuitous_arp           │  0       │
│ 3 │ net.ipv4.conf.default.rp_filter                 │  2       │
│ 4 │ net.ipv4.conf.lo.disable_xfrm                   │  1       │
│ 5 │ net.ipv4.conf.lo.forwarding                     │  0       │
│ 6 │ net.ipv4.ipfrag_low_thresh                      │  3145728 │
│ 7 │ net.ipv6.conf.all.ioam6_id                      │  65535   │
│ 8 │ net.ipv6.conf.all.router_solicitation_interval  │  4       │
│ 9 │ net.mptcp.enabled                               │  1       │
╰───┴─────────────────────────────────────────────────┴──────────╯

4.2.3. Recursively convert FLAC files to OPUS §

A complicated task using a regular shell, recursively find files matching a pattern and then run a given command on each of them, in parallel. Which is exactly what you need if you want to convert your music library into another format, let's convert everything from FLAC to OPUS in this example.

In the following command line, we will look for every .flac file in the subdirectories, then run in parallel using par-each the command ffmpeg on it, from its current name to the old name with .flac changed to .opus.

The let convert and | complete commands are used to store the output of each command into a result table, and store it in the variable convert so we can query it after the job is done.

let convert = (ls **/*flac | par-each { |file| do -i { ffmpeg -i $file.name ($file.name | str replace flac opus) } | complete })

Now, we have a structure in convert that contains the columns stdout, stderr and exit_code, so we can look if all the commands did run correctly using the following query.

$convert | where exit_code != 0

4.2.4. Synchronize a music library to a compressed one §

I had a special need for my phone and my huge music library, I wanted to have a lower quality version of it synced with syncthing, but I needed this to be easy to update when adding new files.

It takes all the music files in /home/user/Music/ and creates a 64K opus file in /home/user/Stream/ by keeping the same file tree hierarchy, and if the opus destination file exists it's skipped.

cd /home/user/Music/
let dest = "/home/user/Stream/"
let convert = (ls **/* |
			where name =~ ".(mp3|flac|opus|ogg)$" | 
			where name !~ "(Audiobook|Piano)" | 
			par-each {
				|file| do -i {
					let new_name = ($file.name | str replace -r ".(flac|ogg|mp3)" ".opus")
					if (not ([$dest, $new_name] | str join | path exists)) {
						mkdir ([$dest, ($file.name | path dirname)] | str join)
						ffmpeg -i $file.name -b:a 64K ([$dest, $new_name] | str join)
					} | complete
				}
			})
$convert

4.2.5. Convert PDF/CBR/CBZ pages into webp and CBZ archives §

I have a lot of digitalized books/mangas/comics, this conversion is a handy operation reducing the size of the files by 40% (up to 70%).

def conv [] {
	if (ls | first | get name | str contains ".jpg") {
	  ls *jpg | par-each {|file| do -i { cwebp $file.name -o ($file.name | str replace jpg webp) } | complete }
          rm *jpg
	}
	if (ls | first | get name | str contains ".ppm") {
	  ls *ppm | par-each {|file| do -i { cwebp $file.name -o ($file.name | str replace ppm webp) } | complete }
	  rm *ppm
	}
}
ls * | each {|file| do -i {
	if ($file.name | str contains ".cbz") { unzip $file.name -d ./pages/ } ;
	if ($file.name | str contains ".cbr") { unrar e -op./pages/ $file.name } ;
        if ($file.name | str contains ".pdf") { mkdir pages ; pdfimages $file.name pages/page } ;
	cd pages ; conv ; cd ../ ; ^zip -r $"($file.name).webp.cbz" pages ; rm -fr pages
} }

4.2.6. Parse gnu tar output §

〉tar vtf nushell.tgz  | parse -r "(.*?) (.*?)\/(.*?)\\s+(.*?) (.*?) (.*?) (.*)" | rename mode owner group size date time path
╭───┬────────────┬────────┬───────┬───────┬────────────┬───────┬────────────────────╮
│ # │    mode    │ owner  │ group │ size  │    date    │ time  │        path        │
├───┼────────────┼────────┼───────┼───────┼────────────┼───────┼────────────────────┤
│ 0 │ drwxr-xr-x │ solene │ wheel │ 0     │ 2022-10-30 │ 16:45 │ nushell            │
│ 1 │ -rw-r--r-- │ solene │ wheel │ 519   │ 2022-10-30 │ 13:41 │ nushell/Makefile   │
│ 2 │ -rw-r--r-- │ solene │ wheel │ 29304 │ 2022-10-29 │ 18:49 │ nushell/crates.inc │
│ 3 │ -rw-r--r-- │ solene │ wheel │ 75003 │ 2022-10-29 │ 13:16 │ nushell/distinfo   │
│ 4 │ drwxr-xr-x │ solene │ wheel │ 0     │ 2022-10-30 │ 00:00 │ nushell/pkg        │
│ 5 │ -rw-r--r-- │ solene │ wheel │ 337   │ 2022-10-29 │ 18:52 │ nushell/pkg/DESCR  │
│ 6 │ -rw-r--r-- │ solene │ wheel │ 14    │ 2022-10-29 │ 18:53 │ nushell/pkg/PLIST  │
╰───┴────────────┴────────┴───────┴───────┴────────────┴───────┴────────────────────╯

4.2.7. Opening spreadsheets §

〉open --raw freq.ods | from ods | get Sheet1 | headers
╭───┬─────────────┬──────────────┬───────────┬─────────┬───────────────┬────────────┬───────┬─────────┬─────────┬──────────╮
│ # │   Policy    │ Compile time │ Idle time │ column3 │ Compile power │ Idle power │ Total │ column8 │ column9 │ column10 │
├───┼─────────────┼──────────────┼───────────┼─────────┼───────────────┼────────────┼───────┼─────────┼─────────┼──────────┤
│ 0 │ powersaving │      1123.00 │      0.00 │         │          5.90 │       0.00 │  5.90 │         │         │          │
│ 1 │ auto        │       871.00 │    252.00 │         │          5.60 │       0.74 │  6.34 │         │    0.44 │     6.94 │
╰───┴─────────────┴──────────────┴───────────┴─────────┴───────────────┴────────────┴───────┴─────────┴─────────┴──────────╯

We can format new strings from columns values.

〉open --raw freq.ods | from ods | get Sheet1 | headers | each {|row| do { echo $"($row.Policy) = ($row.'Compile power' + $row.'Idle power') Watts" } }
╭───┬─────────────────────────╮
│ 0 │ powersaving = 5.9 Watts │
│ 1 │ auto = 6.34 Watts       │
╰───┴─────────────────────────╯

4.2.8. Filter and sort a JSON §

There is a website listing packages that can be updated on OpenBSD at https://portroach.openbsd.org, it provides json of data for rendering.

We can use this data to sort which maintainer has the most up to date percentage, but only if they manage more than 30 packages.

fetch https://portroach.openbsd.org/json/totals.json | get results | where total > 30 | sort-by percentage

4.3. NixOS examples §

4.3.1. Query profiles packages §

nix profile list | parse "{index} {flake} {source} {store}"
╭───┬───────────────────────────────────────────────────────┬──────────────────────────────────────────────────────────────────────────────────┬─────────────────────────────────────────────────────────────────╮
│ # │                         flake                         │                                      source                                      │                              store                              │
├───┼───────────────────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────┤
│ 0 │ flake:nixpkgs#legacyPackages.x86_64-linux.libreoffice │ path:/nix/store/iw3xi0bfszikb0dmyywp7pm590jvbqvs-source?lastModified=1663494472& │ /nix/store/1m6wp1pznhf2nrvs7xwmvig5x3nspq0j-libreoffice-7.2.6.2 │
│   │                                                       │ narHash=sha256-fSowlaoXXWcAM8m9wA6u+eTJJtvruYHMA+Lb%2ftFi%2fqM=&rev=f677051b8dc0 │                                                                 │
│   │                                                       │ b5e2a9348941c99eea8c4b0ff28f#legacyPackages.x86_64-linux.libreoffice             │                                                                 │
│ 1 │ flake:nixpkgs#legacyPackages.x86_64-linux.dino        │ path:/nix/store/9cj1830pvd88lrwmmxw65achd3lw2q9n-source?lastModified=1667050928& │ /nix/store/ljhn4n1q5pk7wr337v681m1h39jp5l2y-dino-0.3.0          │
│   │                                                       │ narHash=sha256-xOn0ZgjImIyeecEsrjxuvlW7IW5genTwvvnDQRFncB8=&rev=fdebb81f45a1ba2c │                                                                 │
│   │                                                       │ 4afca5fd9f526e1653ad0949#legacyPackages.x86_64-linux.dino                        │                                                                 │
╰───┴───────────────────────────────────────────────────────┴──────────────────────────────────────────────────────────────────────────────────┴─────────────────────────────────────────────────────────────────╯

4.3.2. Query flakes §

nix flake show --json | from json
╭────────────────┬───────────────────╮
│ defaultPackage │ {record 5 fields} │
│ packages       │ {record 5 fields} │
╰────────────────┴───────────────────╯

nix flake show --json | from json | get packages
╭────────────────┬───────────────────╮
│ aarch64-darwin │ {record 2 fields} │
│ aarch64-linux  │ {record 2 fields} │
│ i686-linux     │ {record 2 fields} │
│ x86_64-darwin  │ {record 2 fields} │
│ x86_64-linux   │ {record 2 fields} │
╰────────────────┴───────────────────╯

nix flake show --json | from json | get packages.x86_64-linux
╭───────────────┬───────────────────╮
│ nix-dev-html  │ {record 2 fields} │
│ nix-dev-pyenv │ {record 3 fields} │
╰───────────────┴───────────────────╯

4.3.3. Parse a flake.lock file §

> open flake.lock | from json | get nodes.nixpkgs.locked
╭──────────────┬─────────────────────────────────────────────────────╮
│ lastModified │ 1663494472                                          │
│ narHash      │ sha256-fSowlaoXXWcAM8m9wA6u+eTJJtvruYHMA+Lb/tFi/qM= │
│ path         │ /nix/store/iw3xi0bfszikb0dmyywp7pm590jvbqvs-source  │
│ rev          │ f677051b8dc0b5e2a9348941c99eea8c4b0ff28f            │
│ type         │ path                                                │
╰──────────────┴─────────────────────────────────────────────────────╯

4.4. OpenBSD examples §

4.4.1. Parse /etc/fstab §

> open /etc/fstab | from ssv -m 1 -n | rename device mountpoint fs options freq passno
_────┬────────────────────┬─────────────────┬──────┬───────────────────────────────────────────┬──────┬────────_
│  # │       device       │   mountpoint    │  fs  │                  options                  │ freq │ passno │
├────┼────────────────────┼─────────────────┼──────┼───────────────────────────────────────────┼──────┼────────┤
│  0 │ 55a6c21017f858cb.b │ none            │ swap │ sw                                        │ __   │ __     │
│  1 │ 55a6c21017f858cb.a │ /               │ ffs  │ rw,noatime,softdep                        │ 1    │ 1      │
│  2 │ 55a6c21017f858cb.l │ /home           │ ffs  │ rw,noatime,wxallowed,softdep,nodev,nosuid │ 1    │ 2      │
│  3 │ 55a6c21017f858cb.d │ /tmp            │ ffs  │ rw,noatime,softdep,nodev,nosuid           │ 1    │ 2      │
│  4 │ 55a6c21017f858cb.f │ /usr            │ ffs  │ rw,noatime,softdep,nodev                  │ 1    │ 2      │
│  5 │ 55a6c21017f858cb.g │ /usr/X11R6      │ ffs  │ rw,noatime,softdep,nodev                  │ 1    │ 2      │
│  6 │ 55a6c21017f858cb.h │ /usr/local      │ ffs  │ rw,noatime,softdep,wxallowed,nodev        │ 1    │ 2      │
│  7 │ 55a6c21017f858cb.k │ /usr/obj        │ ffs  │ rw,noatime,softdep,nodev,nosuid           │ 1    │ 2      │
│  8 │ 55a6c21017f858cb.j │ /usr/src        │ ffs  │ rw,noatime,softdep,nodev,nosuid           │ 1    │ 2      │
│  9 │ 55a6c21017f858cb.e │ /var            │ ffs  │ rw,noatime,softdep,nodev,nosuid           │ 1    │ 2      │
│ 10 │ afebb2a83a449265.b │ /build          │ ffs  │ rw,noatime,softdep,wxallowed,nosuid       │ 1    │ 2      │
│ 11 │ afebb2a83a449265.a │ /build/pobj     │ ffs  │ rw,noatime,softdep,nodev,wxallowed,nosuid │ 1    │ 2      │
│ 12 │ 55a6c21017f858cb.b │ /build/pobj_mfs │ mfs  │ -s1G,wxallowed,noatime,rw                 │ 0    │ 0      │
╰────┴────────────────────┴─────────────────┴──────┴───────────────────────────────────────────┴──────┴────────_

4.4.2. Parse /var/log/messages §

open /var/log/messages | parse -r "(?<date>\\w+ \\d+ \\d+:\\d+:\\d+) (?<hostname>\\w+) (?<program>\\w+)\\[?(?<pid>\\d+)?\\]?: (?<message>.*)"
╭───┬─────────────────┬──────────┬────────────┬───────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ # │      date       │ hostname │  program   │  pid  │                                                             message                                                             │
├───┼─────────────────┼──────────┼────────────┼───────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ 0 │ Oct 31 10:27:32 │ fx6      │ collectd   │ 55258 │ uc_update: Value too old: name = fx6openbsd/swap/swap-free; value time = 1667208452.108; last cache update = 1667208452.108;    │
│ 1 │ Oct 31 10:43:02 │ fx6      │ collectd   │ 55258 │ uc_update: Value too old: name = fx6openbsd/swap/percent-free; value time = 1667209382.102; last cache update = 1667209382.102; │
│ 2 │ Oct 31 11:00:01 │ fx6      │ syslogd    │ 4629  │ restart                                                                                                                         │
│ 3 │ Oct 31 11:05:26 │ fx6      │ pkg_delete │       │ Removed helix-22.08.1                                                                                                           │
│ 4 │ Oct 31 11:05:29 │ fx6      │ pkg_add    │       │ Added helix-22.08.1                                                                                                             │
│ 5 │ Oct 31 11:16:49 │ fx6      │ pkg_add    │       │ Added llvm-13.0.0p3                                                                                                             │
│ 6 │ Oct 31 11:20:18 │ fx6      │ pkg_add    │       │ Added clang-tools-extra-13.0.0p2                                                                                                │
│ 7 │ Oct 31 11:20:32 │ fx6      │ pkg_add    │       │ Added bash-5.2.2                                                                                                                │
│ 8 │ Oct 31 11:20:34 │ fx6      │ pkg_add    │       │ Added fzf-0.34.0                                                                                                                │
│ 9 │ Oct 31 11:21:01 │ fx6      │ pkg_delete │       │ Removed fzf-0.34.0                                                                                                              │
╰───┴─────────────────┴──────────┴────────────┴───────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

4.4.3. Parse pkg_info output §

pkg_info | str trim |  parse -r "(?<package>.*?)-(?<version>[a-zA-Z0-9\\.]*?) (?<description>.*)"  | str trim description
╭────┬───────────────────┬────────────┬────────────────────────────────────────────────────╮
│  # │      package      │  version   │                    description                     │
├────┼───────────────────┼────────────┼────────────────────────────────────────────────────┤
│  0 │ athn-firmware     │ 1.1p4      │ firmware binary images for athn(4) driver          │
│  1 │ collectd          │ 5.12.0     │ system metrics collection engine                   │
│  2 │ curl              │ 7.85.0     │ transfer files with FTP, HTTP, HTTPS, etc.         │
│  3 │ gettext-runtime   │ 0.21p1     │ GNU gettext runtime libraries and programs         │
│  4 │ intel-firmware    │ 20220809v0 │ microcode update binaries for Intel CPUs           │
│  5 │ inteldrm-firmware │ 20220913   │ firmware binary images for inteldrm(4) driver      │
│  6 │ kakoune           │ 2021.11.08 │ modal code editor with a focus on interactivity    │
│  7 │ libgcrypt         │ 1.10.1p0   │ crypto library based on code used in GnuPG         │
│  8 │ libgpg-error      │ 1.46       │ error codes for GnuPG related software             │
│  9 │ libiconv          │ 1.17       │ character set conversion library                   │
│ 10 │ libstatgrab       │ 0.91p5     │ system statistics gathering library                │
│ 11 │ libxml            │ 2.10.3     │ XML parsing library                                │
│ 12 │ libyajl           │ 2.1.0      │ small JSON library written in ANSI C               │
│ 13 │ nghttp2           │ 1.50.0     │ library for HTTP/2                                 │
│ 14 │ nushell           │ 0.70.0     │ a new kind of shell                                │
│ 15 │ obsdfreqd         │ 1.0.3      │ userland daemon to manage CPU frequency            │
│ 16 │ quirks            │ 6.42       │ exceptions to pkg_add rules and cache              │
│ 17 │ rsync             │ 3.2.5pl0   │ mirroring/synchronization over low bandwidth links │
│ 18 │ ttyplot           │ 1.4p0      │ realtime plotting utility for terminals            │
│ 19 │ vmm-firmware      │ 1.14.0p0   │ firmware binary images for vmm(4) driver           │
│ 20 │ xz                │ 5.2.7      │ LZMA compression and decompression tools           │
│ 21 │ yash              │ 2.52       │ POSIX-compliant command line shell                 │
╰────┴───────────────────┴────────────┴────────────────────────────────────────────────────╯

5. Conclusion §

Nushell is very fun, it's terribly different from regular shells, but it comes with a powerful language and tooling. I always liked shells because of pipes commands, allowing to construct a complex transformation/analysis step by step, and easily inspect any step, or be able to replace a step by another.

With nushell, it feels like I finally have a better tool to create more reliable, robust, portable and faster command pipelines. The learning curve didn't feel too hard, but maybe it's because I'm already used to functional programming.

Search in OpenBSD packages with openports.pl

Written by Solène, on 21 October 2022.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Intro §

This blog post aims to be a quick clarification about the website openports.pl: an online database that could be used to search for OpenBSD packages and ports available in -current.

openports.pl website

2. The setup §

The software used by openports.pl is the package ports-readmes-dancer which uses the sqlite database from the sqlports package.

The host is running OpenBSD -current through snapshots, it tries twice a day to upgrade when possible, and regularly try to upgrade all packages, so it's as fresh as it can be through snapshots.

3. What does this mean? §

The data displayed on openports.pl are accurate because it's directly derived from packages by packaged software you can run on your local system.

4. Sponsor §

While I manage this website, the system is hosted at OpenBSD.Amsterdam for free 🙏 and they also pay for the domain name.

OpenBSD Amsterdam official website

The program packaged in ports-readmes-dancer has been created by espie@, it's using a Perl web framework named Dancer. It's open source software and you can contribute to it if you want to enhance openports.pl itself

ports-readmes-dancer GitHub project page

For security reasons, as it's running "too much" unaudited code server side, it's not possible to host it in the OpenBSD infrastructure under the domain .openbsd.org.

5. Reliable alternatives §

The main alternative is OpenBSD.app, a website but also a command line tool, using sqlports package as a data source, and it supports -stable and -current.

OpenBSD.app

I wrote a GUI application named AppManager (the package name is appmanager) that allows to view all packages available for the running OpenBSD version, and install/remove them. It also has surprisingly effective heuristic to tell if search results are GUI/CLI/other programs.

Blog post about AppManager

A kiosk computer running OpenBSD

Written by Solène, on 11 October 2022.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Let's have fun doing OpenBSD kiosks! As explained in a recent article, a kiosk is a computer dedicated to display things or to be used interactively without being able to escape the current program.

I modified the script surf-display which run the web browser surf in full screen and run various commands to sanitize the environment to prevent users to escape surf to make it compatible with OpenBSD.

surf-display-openbsd project page

surf-display project page

2. Installation §

It's rather simple

  1. git clone https://tildegit.org/solene/surf-display-openbsd
  2. install -m 555 surf-display-openbsd/bin/surf-display /usr/local/bin/
  3. edit ~/.xsession to use /usr/local/bin/surf-display as a window manager

You will also need dependencies:

pkg_add surf wmctrl blackbox xdotool unclutter

Now, when you log in your user, surf will be started automatically, and you can't escape it, so you will need to switch to a TTY if you want to disable it, or through ssh.

3. Configuration §

The configuration is relatively simple for a single screen setup. Edit the file /etc/surf-display and put the URL you want to display as the value of DEFAULT_WWW_URI=, this file will be loaded by surf-display when it runs, otherwise OpenBSD website will be displayed.

4. Conclusion §

It's still a bit rough for OpenBSD, I'd like to add xprintidle to automatically restart the session if the user has been inactive, but it's working really well already!

Boredom land with NixOS

Written by Solène, on 10 October 2022.
Tags: #nixos #life

Comments on Fediverse/Mastodon

1. Introduction §

I like to tinker with systems, push their limits, see how to misuse them and have fun doing unusual setups.

However, since I mostly switched all my computers to NixOS, there is a statement that repeats again and again in my head: NixOS is boring

2. Is it good to be boring? §

The open question may want a different answer depending on the context. For an operating system, I think most people want a boring one which work, and doesn't require having to fight it ever.

In that ground, NixOS is extremely boring. It just works, when you don't want something anymore, remove it from its config, and it's gone. Auto upgrades are reliable, in case of a rare issue after an update, you can still easily rollback.

In two years running the unstable version, I may have had one major issue.

NixOS can be bent in many ways, but can still get its shape back once you are done. It's very annoying to me because it's so smooth I can't find anything to repair.

This is disappointing to me, because I used to have fun with my computers by breaking them, and then learning how to repair it, which often involve a various area of knowledge, but this just never happen with NixOS.

Most people will certainly enjoy something super reliable.

3. The Biggest issue encountered in NixOS §

Here is the story of the biggest problem I had when running NixOS. My disk was full, and I had to delete a few files to make some room, that's it. It wasn't very straightforward because it requires to know where to delete profiles to run the garbage collector manually, but nothing more serious ever happened.

4. Conclusion §

This blog post may look like an ode to NixOS, but I'm really disappointed. Actually, now I need to find something to do on my computer which is not in the list ["fix the operating system"].

I suppose someone enjoying mechanics may feel the same when using a top-notch electric bike with high grade components made to be reliable.

Linux BTRFS continuous snapshots

Written by Solène, on 07 October 2022.
Tags: #linux #nixos #btrfs #backup

Comments on Fediverse/Mastodon

1. Introduction §

As shown in my previous article about the NILFS file system, continuous snapshots are great and practical as they can save you losing data accidentally between two backups jobs.

Today, I'll demonstrate how to do something quite similar using BTRFS and regular snapshots.

In the configuration, I'll show the code for NixOS using the tool btrbk to handle snapshots retention correctly.

Snapshots are not backups! It is important to understand this. If your storage is damaged or the file system get corrupted, or the device stolen, you will lose your data. Backups are archives of your data that are on another device, and which can be used when the original device is lost/destroyed/corrupted. However, snapshots are superfast and cheap, and can be used to recover accidentally deleted files.

btrbk official website

2. NixOS configuration §

The program btrbk is simple, it requires a configuration file /etc/btrbk.conf defining which volume you want to snapshot regularly, where to make them accessible and how long you want to keep them.

In the following example, we will keep the snapshots for 2 days, and create them every 10 minutes. A SystemD service will be scheduled using a timer in order run btrbk run which handle snapshot creation and pruning. Snapshots will be made available under /.snapshots/.

  environment.etc = {
    "btrbk.conf".text = ''
      snapshot_preserve_min   2d
      volume /
        snapshot_dir .snapshots
        subvolume home
    '';
  };
  
  systemd.services.btrfs-snapshot = {
    startAt = "*:0/10";
    enable = true;
    path = with pkgs; [btrbk];
    serviceConfig.Type = "oneshot";
    script = ''
      mkdir -p /.snapshots
      btrbk run
    '';
  };

Rebuild your system, you should now have systemd units btrfs-snapshot.service and btrfs-snapshot.timer available.

As the configuration file will be at the standard location, you can use btrbk as root to manually list or prune your snapshots in case you need to, like immediately reclaiming disk space.

3. Using NixOS module §

After publishing this blog post, I realized a NixOS module existed to simplify the setup and provide more features. Here is the code used to replicate the behavior of the code above.

{
  services.btrbk.instances."btrbk" = {
    onCalendar = "*:0/10";
    settings = {
      snapshot_preserve_min = "2d";
      volume."/" = {
        subvolume = "/home";
        snapshot_dir = ".snapshots";
      };
    };
  };
}

You can find more settings for this module in the man page configuration.nix.

Note that with this module, you need to create the directory .snapshots manually before btrbk can work.

4. Going further §

btrbk is a powerful tool, as not only you can create snapshots with it, but it can stream them on a remote system with optional encryption. It can also manage offline backups on a removable media and a few other non-simple cases. It's really worth taking a look.

A NixOS kiosk

Written by Solène, on 06 October 2022.
Tags: #linux #security #nixos

Comments on Fediverse/Mastodon

1. Introduction §

A kiosk, in the sysadmin jargon, is a computer that is restricted to a single program so anyone can use it for the sole provided purpose. You may have seen kiosk computers here and there, often wrapped in some kind of box with just a touch screen available. ATM are kiosks, most screens showing some information are also kiosks.

What if you wanted to build a kiosk yourself? For having done a bunch of kiosk computers a few years ago, it's not an easy task, you need to think about:

  • how to make boot process bullet proof?
  • which desktop environment to use?
  • will the system show notifications you don't want?
  • can the user escape from the kiosk program?

Nowadays, we have more tooling available to ease kiosk making. There is also a distinction that has to be made between kiosks used displaying things, and kiosks used by users. The latter is more complicated and require lot of work, the former is a bit easier, especially with the new tools we will see in this article.

2. Cage §

The tool used in this blog post is named Cage, it's a program running a Wayland display that only allow one single window to be shown at once.

Cage GitHub project page

Using cage, we will be able to start a program in fullscreen, and only it, without having any notification, desktop, title bar etc...

In my case, I want to open firefox to open a local file used to display monitoring information. Firefox can still be used "normally" because hardening it would require a lot of work, but it's fine because I'm at home and it's just to display gauges and diagrams.

3. NixOS configuration §

Here is the piece of code that will start the firefox window at boot automatically. Note that you need to disable any X server related configuration.

  services.cage = {
      enable = true;
      user = "solene";
      program = "${pkgs.firefox}/bin/firefox -kiosk -private-window file:///home/solene/monitoring.html";
  };

Firefox has a few special flags, such as -kiosk to disable a few components, and -private-window to not mix with the current history. This is clearly not enough to prevent someone to use Firefox for whatever they want, but it's fine to handle a display of a single page reliably.

4. Conclusion §

I wish I had something like Cage available back in the time I had to make kiosks. I can enjoy my low power netbook just displayin monitoring graphs at home now.

a netbook displaying graphs
a netbook displaying graphs

Linux NILFS file system: automatic continuous snapshots

Written by Solène, on 05 October 2022.
Tags: #linux #filesystem #nilfs

Comments on Fediverse/Mastodon

1. Introduction §

Today, I'll share about a special Linux file system that I really enjoy. It's called NILFS and has been imported into Linux in 2009, so it's not really a new player, despite being stable and used in production it never got popular.

In this file system, there is a unique system of continuous checkpoint creation. A checkpoint is a snapshot of your system at a given point in time, but it can be deleted automatically if some disk space must be reclaimed. A checkpoint can be transformed into a snapshot that will never be removed.

This mechanism works very well for workstations or file servers on which redundancy is nonexistent, and on which backups are done every day/weeks which give room for unrecoverable mistakes.

NILFS project official website

Wikipedia page about NILFS

2. NILFS concepts §

As NILFS is a Copy-On-Write file system (CoW), which mean when you make a change to a file, the original chunk on the disk isn't modified but a new chunk is created with the new content, this play well with making an history of the files.

From my experience, it performs very well on SSD devices on a desktop system, even during heavy I/O operation.

The continuous checkpoint creation system may be very confusing, so I'll explain how to learn about this mechanism and how to tame it.

3. Garbage collection §

The concept of a garbage collector may appear given for most people, but if it doesn't speak to you, let me give a quick explanation. In computer science, a garbage collector is a task that will look at unused memory and make it available again.

On NILFS, as a checkpoint is created every few seconds, used data is never freed and one would run out of disk pretty quickly. But here is the nilfs_cleanerd program, the garbage collector, that will look at the oldest checkpoint and delete them to reclaim the disk space under certain condition. Its default strategy is trying to keep checkpoints as long as possible, until it needs to make some room to avoid issues, it may not suit a workload creating a lot of files and that's why it can be tuned very precisely. For most desktop users, the defaults should work fine.

The garbage collector is automatically started on a volume upon mount. You can use the command nilfs-clean to control that daemon, reload its configuration, stop it etc...

When you delete a file on a NILFS file system, it doesn't free up any disk space because it's still available in a previous checkpoint, you need to wait for the according checkpoints to be removed to have some space freed.

4. How to find the current size of your data set §

As the output of df for a NILFS filesystem will give you the real data used on the disk for your data AND the snapshots/checkpoints, it can't be used to know how much free disk is available/used.

In order to figure the current disk usage (without accounting older checkpoints/snapshots), we will use the command lscp to look at the number of blocks contained in the most recent checkpoint. On Linux, a block is 4096 bytes, we can then turn the total in bytes into gigabytes by dividing three time by 1024 (bytes -> kilobytes -> megabytes -> gigabytes).

lscp | awk 'END { print $(NF-1)*4096/1024/1024/1024 }'

This number is the current size of what you have on the partition.

5. Create a checkpoint / snapshot §

It's possible to create a snapshot of your current system state using the command mkcp.

mkcp --snapshot

Or you can turn a checkpoint into a snapshot using the command chcp.

chcp ss /dev/sda1 28579

The opposite operation (snapshot to checkpoint) can be done using chcp cp.

6. How to recover files after a big mistake §

Let's say you deleted an important in-progress work, you don't have any backup and no way to retrieve it, fortunately you are using NILFS and a checkpoint was created every few seconds, so the files are still there and at reach!

The first step is to pause the garbage collector to avoid losing the files: nilfs-clean --suspend. After this, we can think slowly about the next steps without having to worry.

The next step is to list the checkpoints using the command lscp and look at the date/time in which the files still existed and preferably in their latest version, so the best is to get just before the deletion.

Then, we can mount the checkpoint (let's say number 12345 for the example) on a different directory using the following command:

mount -t nilfs2 -r -o cp=12345 /dev/sda1 /mnt

If it went fine, you should be able to browse the data in /mnt to recover your files.

Once you finished recovering your files, umount /mnt and resume the garbage collector with nilfs-clean --resume.

7. Going further §

Here is a list of extra pieces you may want to read to learn more about nilfs2:

  • nilfs_cleanerd and nilfs_cleanerd.conf man pages to tune the garbage collector
  • man pages for lscp / mkcp / rmcp / chcp to manage snapshots and checkpoints manually

My open-source machine learning toolbox

Written by Solène, on 04 October 2022.
Tags: #linux #opensource #machinelearning #ml

Comments on Fediverse/Mastodon

1. Introduction §

I recently got interested into what's possible with machine learning programs, and this has been an exciting journey. Let me share about a few programs I added to my toolbox.

They all work well on NixOS, but they might require specific instructions to work except for upscayl and whisper that are in nixpkgs. However, it's not that hard, but may not be accessible to everyone.

2. Whisper §

This program analyzes audio content of an audio or video file, and make a transcript of it. It supports many languages, I tried it with English, French and Japanese, and it worked very reliably.

Not only it creates a transcript text file, but it also generates a subtitles (.srt) file, you can create video subtitles automatically. It has a translation function which pass all the transcript text to Google translate and give you the result in English.

It's quite slow using a CPU, but it definitely works, using a GPU gives an 80 times speed boost.

It requires a weight to work, it exists in different sizes: tiny, small, base, medium, large, and each has an English only variant that is smaller. It will download them automatically on demand in the ~/.cache/whisper/ directory.

whisper GitHub project page

3. Stable-diffusion §

This program can be used to generate pictures from a sentence, it's actually very effective. You need a weight file which is like a database on how to interpret stuff in the sentence.

You need an account on https://huggingface.co/CompVis/stable-diffusion-v-1-4-original to download the free weight file (4 GB).

a man on a horse, black and white
a man on a horse, black and white
Solid Snakes on a unicorn in a cyberpunk style
Solid Snakes on a unicorn in a cyberpunk style

stable-diffusion GitHub project page

stable-diffusion GitHub project page with openvino support for CPU based rendering

4. DeOldify.NET §

This program can be used to colorize a picture. The weights are provided. This works well without a GPU.

I tried to use it on mangas, it works to some extent, it adds some shading and identify things with colors, but the colorization isn't reliable and colors may be weird. However, this improves readability for me 👍🏻.

a man on a horse, black and white but colorized with DeOldify
a man on a horse, black and white but colorized with DeOldify

DeOldify.NET GitHub project page

5. Upscayl §

This program upscales a picture to 4 times its resolution, the result can be very impressive, but in some situation it gives a "plastic" and unnatural feeling.

I've been very impressed by it, I've been able to improve some old pictures taken with a poor phone.

a man on a horse, black and white but colorized with DeOldify and upscaled with Upscayl
a man on a horse, black and white but colorized with DeOldify and upscaled with Upscayl

Upscayl GitHub project page

6. Going further §

If you know some tools in that kind that could interest me, please share! :) Especially if it's something to colorize mangas 😁.

Extending fail2ban on NixOS

Written by Solène, on 02 October 2022.
Tags: #linux #nixos #fail2ban #security

Comments on Fediverse/Mastodon

1. Introduction §

Fail2ban is a wonderful piece of software, it can analyze logs from daemons and ban them in the firewall. It's triggered by certain conditions like a single IP found in too many lines matching a pattern (such as a login failure) under a certain time.

What's even cooler is that writing new filters is super easy! In this text, I'll share how to write new filters for NixOS.

fail2ban GitHub project page

NixOS official website

2. Terminology §

Before continuing, if you are not familiar with fail2ban, here are the few important keywords to understand:

  • action: what to do with an IP (usually banning an IP)
  • filter: set of regular expressions and information used to find bad actors in logs
  • jail: what ties together filters and actions in a logical unit

For instance, a sshd jail will have a filter applied on sshd logs, and it will use a banning action. The jail can have more information like how many times an IP must be found by a filter before using the action.

3. Configuration §

3.1. Enabling fail2ban §

The easiest part is to enable fail2ban. Take the opportunity to declare IPs you don't want to block, and also block IPs on all ports if it's something you want.

  services.fail2ban = {
    enable = true;
    ignoreIP = [
      "192.168.1.0/24"
    ];
  };

  # needed to ban on IPv4 and IPv6 for all ports
  services.fail2ban = {
    extraPackages = [pkgs.ipset];
    banaction = "iptables-ipset-proto6-allports";
  };

3.2. Creating new filters §

A filter is composed of one/many regex, and also a systemd journal unit in case you are pulling information from it instead of a log file.

We will use the module environment.etc to create files in /etc/fail2ban/filter.d/ directory, so they can be used in the jails.

These are examples of filters you may want to use. They target very large, this may not be ideal for your use case, but can serve as a good start.

  environment.etc = {
    "fail2ban/filter.d/molly.conf".text = ''
      [Definition]
      failregex = <HOST>\s+(31|40|51|53).*$
    '';

    "fail2ban/filter.d/nginx-bruteforce.conf".text = ''
      [Definition]
      failregex = ^<HOST>.*GET.*(matrix/server|\.php|admin|wp\-).* HTTP/\d.\d\" 404.*$
    '';

    "fail2ban/filter.d/postfix-bruteforce.conf".text = ''
      [Definition]
      failregex = warning: [\w\.\-]+\[<HOST>\]: SASL LOGIN authentication failed.*$
      journalmatch = _SYSTEMD_UNIT=postfix.service
    '';
  };

3.3. Defining the jails using our new filters §

Now we can declare fail2ban jails with each filter we created. If you use a log file, make sure to have backend = auto, otherwise the systemd journal is used and this won't work.

The most important settings are:

  • filter: choose your filter using its filename minus the .conf part
  • maxretry: how many times an IP should be reported before taking an action
  • findtime: how long should we keep entries to match in maxretry
  services.fail2ban.jails = {

    # max 6 failures in 600 seconds
    "nginx-spam" = ''
      enabled  = true
      filter   = nginx-bruteforce
      logpath = /var/log/nginx/access.log
      backend = auto
      maxretry = 6
      findtime = 600
    '';

    # max 3 failures in 600 seconds
    "postfix-bruteforce" = ''
      enabled = true
      filter = postfix-bruteforce
      findtime = 600
      maxretry = 3
    '';

    # max 10 failures in 600 seconds
    "molly" = ''
      enabled = true
      filter = molly
      findtime = 600
      maxretry = 10
      logpath = /var/log/molly-brown/access.log
      backend = auto
    '';
  };

4. Creating filters §

It's actually easy to create filters, fail2ban provides a good framework like automatic date and host detection, which make creating regex very easy.

You can use the command fail2ban-regex to experiment with regexes on some logs.

Here is an example of a log file that would contain an IP and an error message:

fail2ban-regex /var/log/someservice.log "<HOST> ERROR"

Here is an example of a systemd unit log that would contain an IP, then a space and a 403 error:

fail2ban-regex -m _SYSTEMD_UNIT=someservice.service systemd-journal "<HOST> 403"

You can analyze what lines matched or not with the flags --print-all-matched and --print-all-missed.

I recommend you to read fail2ban man pages and --help output if you want to create filters.

5. Conclusion §

Fail2ban is a fantastic tool to easily create filtering rules to ban the bad actors. It turned out most rules didn't work out of the box, or were too narrow for my use case, so extending fail2ban was quite straightforward.

Automatically ban ports scanner IPs on NixOS

Written by Solène, on 29 September 2022.
Tags: #linux #security #nixos #firewall

Comments on Fediverse/Mastodon

1. Introduction §

Since I switched my server from OpenBSD to NixOS, I was missing a feature. The previous server was using iblock, a program I made to block IPs connecting on a list of ports, I don't like people knocking randomly on ports.

iblock is simple, if you connect to any port on which it's listening, you get banned in the firewall.

iblock project page

I reimplemented it using iptables on NixOS.

2. How it works §

Iptables provides a feature adding an IP to a set if the address connects n times before s seconds. Let's just set it to ONCE so the address is banned on first connection.

For the record, a "set" is an extra iptables feature allowing to add many IP addresses like an OpenBSD PF table. We need separate sets for IPv4 and IPv6, they don't mix well.

3. The implementation §

You can create a new nix file with this content and add it to the imports of your configuration file.

{
  lib,
  pkgs,
  ...
}: let
  wan_interface = "eth0";
  ports-to-block = "21,23,53,111,135,137,138,139,445,1433,25565,5432,3389,3306,27019";

  # block people 10 days
  expire = 60 * 60 * 24 * 10; # in seconds, 0 to disable expiration , max is 2147483

  rules = table: [
    "INPUT -i ${wan_interface} -p tcp -m multiport --dports ${ports-to-block} -m state --state NEW -m recent --set"
    "INPUT -i ${wan_interface} -p tcp -m multiport --dports ${ports-to-block} -m state --state NEW -m recent --update --seconds 10 --hitcount 1 -j SET --add-set ${table} src"
    "INPUT -i ${wan_interface} -p tcp -m set --match-set ${table} src -j nixos-fw-refuse"
    "INPUT -i ${wan_interface} -p udp -m set --match-set ${table} src -j nixos-fw-refuse"
  ];

  create-rules =
    lib.concatStringsSep "\n"
    (
      builtins.map (rule: "iptables -C " + rule + " || iptables -A " + rule) (rules "blocked")
      ++ builtins.map (rule: "ip6tables -C " + rule + " || ip6tables -A " + rule) (rules "blocked6")
    );

  delete-rules =
    lib.concatStringsSep "\n"
    (
      builtins.map (rule: "iptables -C " + rule + " && iptables -D " + rule) (rules "blocked")
      ++ builtins.map (rule: "ip6tables -C " + rule + " && ip6tables -D " + rule) (rules "blocked6")
    );
in {
  networking.firewall = {
    enable = true;
    extraPackages = [pkgs.ipset];

    extraCommands = ''
      if test -f /var/lib/ipset.conf
      then
          ipset restore -! < /var/lib/ipset.conf
      else
          ipset -exist create blocked hash:ip ${
        if expire > 0
        then "timeout ${toString expire}"
        else ""
      }
          ipset -exist create blocked6 hash:ip family inet6 ${
        if expire > 0
        then "timeout ${toString expire}"
        else ""
      }
      fi
      ${create-rules}
    '';

    extraStopCommands = ''
      ipset -exist create blocked hash:ip ${
        if expire > 0
        then "timeout ${toString expire}"
        else ""
      }
      ipset -exist create blocked6 hash:ip family inet6 ${
        if expire > 0
        then "timeout ${toString expire}"
        else ""
      }
      ipset save > /var/lib/ipset.conf
      ${delete-rules}
    '';
  };
}

To explain this implementation without going into details:

  • rules are generated for IPv4 and IPv6
  • rules are generated with a check if they exist before adding or removing them
  • ipset are created if they don't exist, and loaded / saved on disk in /var/lib/ipset.conf on start / stop

4. Caveat §

The configuration isn't stateless, it creates a file /var/lib/ipset.conf , so if you want to make changes like expiration time to the sets while they already exist, you will need to use ipset yourself.

And most importantly, because of the way the firewall service is implemented, if you don't use this file anymore, the firewall won't reload.

I've lost a lot of time figuring why: when NixOS reloads the firewall service, it uses the new reload script which doesn't include the cleanup from stopCommand, and this fails because the NixOS service didn't expect anything in the INPUT chain.

sept. 29 23:24:22 interbus systemd[1]: Reloading Firewall...
sept. 29 23:24:22 interbus firewall-reload[94376]: iptables: Chain already exists.
sept. 29 23:24:22 interbus firewall-reload[94340]: Failed to reload firewall... Stopping
sept. 29 23:24:22 interbus systemd[1]: firewall.service: Control process exited, code=exited, status=1/FAILURE
sept. 29 23:24:22 interbus systemd[1]: Reload failed for Firewall.

In this case, you have to manually delete the rules in the INPUT chain in for IPv4 and IPv6, or reboot your system that will start with a fresh set, or flush all rules in iptables and restart the firewall service.

5. Conclusion §

I'll be able to publish again a list of IPs scanning my server, and this is also fun to see the list growing every minute.

Avoid Linux locking up in low memory situations using earlyoom

Written by Solène, on 28 September 2022.
Tags: #linux #nixos #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

Within operating system kernels, at least for Linux and the BSDs, there is a mechanism called "out of memory killer" which is triggered when the system is running out of memory and some room must be made to make the system responsive again.

However, in practice this OOM mechanism doesn't work well. If the system is running out of memory, it will become totally unresponsive, and sometimes the OOM killer will help, but it may take like 30 minutes, but sometimes it may be stuck forever.

Today, I stumbled upon a nice project called "earlyoom", which is an OOM manager working in the user land instead of inside the kernel, which gives it a lot more flexibility about its actions and the consequences.

earlyoom GitHub project page

2. How it works §

earlyoom is simple in that it's a daemon running as root, using nearly no memory, that will regularly poll for remaining swap memory and RAM memory, if the current level are below the threshold of both, actions will be taken.

What's cool is you can tell it to prefer some processes to terminate first, and some processes to avoid as much as possible. For some people, it may be preferable to terminate a web browser first and instant messaging than their development software.

I use it with the following parameters:

earlyoom -m 2 -s 2 -r 3600 -g --avoid '^(X|plasma.*|konsole|kwin)$' --prefer '^(electron|libreoffice|gimp)$'

The command line above means that if my system has less than 2% of its RAM and less than 2% of its swap available, earlyoom will try to terminate existing program whose binary matches electron/libreoffice/gimp etc.... and avoid programs named X/Plasma.*/konsole/kwin.

For configuring it properly as a service, explanations can be found in the project README file.

3. NixOS setup §

On NixOS, there is a module for earlyoom, to configure it like in the example above:

{
  services.earlyoom = {
      enable = true;
      freeSwapThreshold = 2;
      freeMemThreshold = 2;
      extraArgs = [
          "-g" "--avoid '^(X|plasma.*|konsole|kwin)$'"
          "--prefer '^(electron|libreoffice|gimp)$'"
      ];
  };
}

4. Conclusion §

This program is a pleasant surprise to me, I often run out of memory on my laptop because I'm running some software requiring a lot of memory for good reasons, and while the laptop has barely enough memory to run them, I should have most of the other software close to make it fit in. However, when I forget to close them, the system would just lock up for a while, which most often require a hard reboot. Being able to avoid this situation is a big plus for me. Of course, adding some swap space would help, but I prefer to avoid adding more swap as it's terribly inefficient and only postpone the problem.

How to trigger services restart after OpenBSD update

Written by Solène, on 25 September 2022.
Tags: #openbsd #security #deployment

Comments on Fediverse/Mastodon

1. Introduction §

Keeping an OpenBSD system up-to-date requires two daily operation:

  • updating the base system with the command: /usr/sbin/syspatch
  • updating the packages (if any) with the command: /usr/sbin/pkg_add -u

However, OpenBSD isn't very friendly with regard to what to do after upgrading: modified binaries should be restarted to use the new code, and a new kernel requires an upgrade

It's not useful to update if the newer binaries are never used.

2. Syspatch reboot §

I wrote a small script to automatically reboot if syspatch deployed a new kernel. Instead of running syspatch from a cron job, you can run a script with this content:

#!/bin/sh

OUT=$(/usr/sbin/syspatch)
SUCCESS=$?

if [ "$SUCCESS" -eq 0 ]
then
    if echo "$OUT" | grep reboot >/dev/null
    then
        reboot
    fi
fi

It's not much, it runs syspatch and if the output contains "reboot", then a reboot of the system is done.

3. Binaries restart §

It's getting more complicated when a running program is updated, whether it's a service with a rc.d script, or a program currently in use.

This would be nice to see something to help to restart them appropriately, I currently use the program checkrestart in a script like this:

checkrestart | grep smtpd && rcctl restart smtpd
checkrestart | grep httpd && rcctl restart httpd
checkrestart | grep dovecot && rcctl restart dovecot
checkrestart | grep lua && rcctl restart prosody

This works well for system services, except when the binary is different from the service name like for prosody, in which case you must know the exact name of the binary.

But for long-lived commands like a 24/7 emacs or an IRC client, there isn't any mechanism to handle it. At best, you can email you checkrestart output, or run checkrestart upon SSH login.

My NixOS workflow after migrating from OpenBSD

Written by Solène, on 24 September 2022.
Tags: #openbsd #nixos #life

Comments on Fediverse/Mastodon

1. Introduction §

After successfully switching my small computer fleet to NixOS, I'd like to share about the journey.

I currently have a bunch of computers running NixOS:

  • my personal laptop
  • the work laptop
  • home router
  • home file server
  • some home lab computer
  • e-mail / XMPP / Gemini server hosted at openbsd.amsterdam

That sums up to 6 computers running NixOS, half of them is running the development version, and the other is running the latest release.

2. Migration §

2.1. From OpenBSD to NixOS §

All the computers above used to run OpenBSD, let me explain why I migrated. It was a very complicated choice for me, because I still like OpenBSD despite I uninstalled it.

  • NixOS offers more software choice than OpenBSD, this is especially true for recent software, and porting them to OpenBSD is getting difficult over time.
  • After spending too much time with OpenBSD, I wanted to explore a whole new world, NixOS being super different, it was a good opportunity. As a professional IT worker, it's important for me to stay up to date, Linux ecosystem evolved a lot over that past ten years. What's funny is OpenBSD and NixOS share similar issues such as not being able to use binaries found on the Internet (but for various reasons)
  • NixOS maintenance is drastically reduced compared to OpenBSD
  • NixOS helps me to squeeze more from my hardware (speed, storage capacity, reliability)
  • systemd: I bet this one will be controversial, but since I learned how to use it, I really like it (and NixOS make it even greater for writing units)

Security is hard to measure, but it's the main argument in favor of OpenBSD, however it is possible to enable mitigations on Linux as well such as hardened memory allocator or a hardened Kernel. OpenBSD isn't practical to separate services from running all in the same system, while on Linux you can easily sandbox services. In the end, the security mechanisms are different, but I feel the result is pretty similar for my threat model of protecting against script kiddies.

I give a bonus point for Linux for its ability to account CPU/Memory/Swap/Disk/network per user, group and process. This allows spotting unusual activity. Security is about protection, but also about being aware of intrusion, OpenBSD isn't very good at it at the moment.

2.2. NixOS modules §

One issue I had migrating my mail server and the router was to find what changes were made in /etc. I was able to figure which services were enabled, but not really all the steps done a few years ago to configure them. I had to scrape all the configuration file to see if it looked like verbatim default configuration or something I changed manually.

This is where NixOS shines for maintenance and configuration, everything is declarative, so you never touch anything in /etc. At anytime, even in a few years, I'll be able to exactly tell what I need for each service, without having to dig up /etc/ and compare with default files. This is a saner approach, and also ease migration toward another system (OpenBSD? ;) ) because I'd just have to apply these changes to configuration files.

3. Workflow §

Working with NixOS can be disappointing. Most of the system is read-only, you need to learn a new language (Nix) to configure services, you have to "rebuild" your system to make a change as simple as adding an entry in /etc/hosts, not very "Unix-like".

Your biggest friend is the man page configuration.nix which contains all the possible configurations settings available in NixOS, from Kernel choice and grub parameters, to Docker containers started at boot or your desktop environment.

The workflow is pretty easy, take your configuration.nix file, apply changes to it, and run "nixos-rebuild test" (or switch if you prefer) to try the changes. Then, you may want something more elaborated like tracking your changes in a git or darcs repository, and start sharing pieces of configuration between machines.

But in the end, you just declare some configuration. I prefer to keep my configurations very easy to read, I still don't have any modules or much variable, the common pieces are just .nix files imported for the systems needing it. It's super easy to track and debug.

4. Bento §

Bento GitHub project page

After a while, I found it very tedious to have to run nixos-rebuild on each machine to keep them up to date, so I started using the autoUpgrade module which basically do it for you in a scheduled task.

But then, I needed to centralize each configuration file somewhere, and have fun with ssh keys because I don't like publishing my configuration files publicly. Which isn't optimal either as if you make a change locally, you need to push the changes and connect to the remote host to pull the changes and rebuild immediately instead of waiting for the auto upgrade process.

So, I wrote bento, which allows me to manage all the configuration files in a single place, but better than that, I can build the configuration locally to ensure they will work once shipped. I quickly added a way to track the status of each remote system to be sure they picked up and applied the changes (every 10 minutes). Later, I improved the network efficiency by central management computer as a local binary cache, so other systems are now downloading packages from it locally, instead of downloading them again from the Internet.

The coolest thing ever is that I can manage offline systems such as my work laptop, I can update its configuration file in the weekend for an update or to improve the environment (it mostly shares the same configuration as my main laptop), and it will automatically pick it up when I boot it.

5. Conclusion §

Moving to NixOS was a very good and pleasant experience, but I had some knowledge about it before starting. It might be confusing a lot of people, and you certainly need to get into NixOS mindset to appreciate it.

Sharing some statistics about BTRFS compression

Written by Solène, on 21 September 2022.
Tags: #btrfs #filesystem

Comments on Fediverse/Mastodon

1. Introduction §

As I'm moving to Linux more and more, I took the opportunity to explore the BTRFS file system which was mostly unknown to me.

Let me share some data about compression ratio with BTRFS (ZFS should give similar results).

2. Work laptop §

2.1. First data §

This is my work computer with a big Nix store, and some build programs involving a lot of cache files and many git repositories.

Processed 3570629 files, 894690 regular extents (1836135 refs), 2366783 inline.
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       61%       55G          90G         155G
none       100%       35G          35G          52G
zlib        37%       20G          54G         102G
prealloc   100%      138M         138M          67M

The output reads that the real disk usage is 61%, so 39% of the disk compressed data. We have more details per compression algorithm about the content, none represents uncompressed data and zlib the files compressed using this algorithm.

Files compressed with zlib are down to 37% of their real size, this is not bad. I made a mistake when creating the BTRFS mount point: I used zlib compression algorithm which is quite obsolete nowadays. For history record, zlib is the library used to provide the "deflate compression algorithm" found in zip or gzip.

Let's change the compression to use zstd algorithm instead. This can be changed with the command btrfs filesystem defrag -czstd -r /. Basically, all files are scanned, if they can be compressed with zstd, they are rewritten on the disk with the new algorithm.

2.2. Data after switching to zstd §

After 37 minutes of recompressing everything, the results are surprising. It didn't change much!

Processed 3570427 files, 928646 regular extents (1869080 refs), 2364661 inline.
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       60%       54G          90G         155G
none       100%       33G          33G          51G
zstd        37%       21G          56G         104G
prealloc   100%      138M         138M          67M

Real data usage on the disk is now 60% instead of 61% with zlib, not much of an improvement, I'd have expected zstd to perform a lot better.

However, I didn't measure compression and decompression times. zstd should perform a lot better in this area, so I'll stick with zstd.

LinuxReviews: comparison of compression algorithms

3. Personal computer §

My own laptop has a huge Nix store, a lot of binaries files (music, pictures), a few hundreads of gigabytes of video games. I suppose it's quite a realistic and balanced environment.

Processed 1804099 files, 755845 regular extents (1295281 refs), 980697 inline.
Type       Perc     Disk Usage   Uncompressed Referenced
TOTAL       93%      429G         459G         392G
none       100%      414G         414G         332G
zstd        34%       15G          45G          59G
prealloc   100%       92M          92M          91M

The saving due to compression is 30 GB, but this only count as 7% of the global file system. That's not impressive compared to the other computer, but having an extra 30 GB for free is clearly something I enjoy.

Using Arion to use NixOS modules in containers

Written by Solène, on 21 September 2022.
Tags: #nixos #containers #docker #podman

Comments on Fediverse/Mastodon

1. Introduction §

NixOS is cool, but it's super cool because it has modules for many services, so you don't have to learn how to manage them (except if you want them in production), and you don't need to update them like a container image.

But it's specific to NixOS, while the modules are defined in the nix nixpkgs repository, you can't use them if you are not using NixOS.

But there is a trick, it's called arion and is able to generate containers to leverage NixOS modules power in them, without being on NixOS. You just need to have Nix installed locally.

arion GitHub project page

Nix project page

2. Docker vs Podman §

Long story short, docker is a tool to manage containers but requires going through a local socket and root daemon to handle this. Podman is a docker drop-in alternative that is almost 100% compatible (including docker-compose), and can run containers in userland or through a local daemon for more privileges.

Arion works best with podman, this is so because it relies on some systemd features to handle capabilities, and docker is diverting from this while podman isn't.

Explanations about why Arion should be used with podman

3. Prerequisites §

In order to use arion, I found these prerequisites:

  • nix must be in path
  • podman daemon running
  • docker command in path (arion is calling docker, but to use podman)
  • export DOCKER_HOST=unix:///run/podman/podman.sock

4. Different modes §

Arion can create different kind of container, using more or less parts of NixOS. You can run systemd services from NixOS, or a full blown NixOS and its modules, this is what I want to use here.

There are examples of the various modes that are provided in arion sources, but also in the documentation.

Arion documentation

Arion GitHub project page: examples

5. Let's try! §

We are now going to create a container to run a Netdata instance:

Create a file arion-compose.nix

{
  project.name = "netdata";
  services.netdata = { pkgs, lib, ... }: {
    nixos.useSystemd = true;
    nixos.configuration.boot.tmpOnTmpfs = true;

    nixos.configuration = {
      services.netdata.enable = true;
    };

    # required for the service, arion tells you what is required
    service.capabilities.SYS_ADMIN = true;

    # required for network
    nixos.configuration.systemd.services.netdata.serviceConfig.AmbientCapabilities =
      lib.mkForce [ "CAP_NET_BIND_SERVICE" ];

    # bind container local port to host port
    service.ports = [
      "8080:19999" # host:container
    ];
  };
}

And a file arion-pkgs.nix

import <nixpkgs> {
  system = "x86_64-linux";
}

And then, run arion up -d, you should have Netdata reachable over http://localhost:8080/ , it's managed like any docker / podman container, so usual commands work to stop / start / export the container.

Of course, this example is very simple (I choose it for this reason), but you can reuse any NixOS module this way.

6. Making changes to the network §

If you change the network parts, you may need to delete the previous network creating in docker. Just use docker network ls to find the id, and docker network rm to delete it, then run arion up -d again.

7. Conclusion §

Arion is a fantastic tool allowing to reuse NixOS modules anywhere. These modules are a huge weight in NixOS appeal, and being able to use them outside is a good step toward a ubiquitous Nix, not only to build programs but also to run services.

Using Netdata on NixOS and connecting to Netdata cloud

Written by Solène, on 16 September 2022.
Tags: #nixos #monitoring #netdata #cloud

Comments on Fediverse/Mastodon

1. Introduction §

I'm still playing with monitoring programs, and I've been remembered about Netdata. What an improvement over the last 8 years!

This tutorial explains how to get Netdata installed on NixOS, and how to register your node in Netdata cloud.

Netdata GitHub project page

Netdata live demo

2. What's Netdata? §

This program is a simple service to run on a computer, it will automatically gather a ton of metrics and make them easily available over the local TCP port 19999. You just need to run Netdata and nothing else, and you will have every metrics you can imagine from your computer, and some explanations for each of them!

That's pretty cool because Netdata is very efficient, it draws nearly no CPU while gathering a few thousands metrics every few seconds, and is memory efficient and can be constrained to a dozen of megabytes.

While you can export its metrics to something like graphite or Prometheus, you lose the nice display which is absolutely a blast compare to Grafana (in my opinion).

Update: as pointed out by a reader (thanks!), it's possible to connect Netdata instances to only one used for viewing metrics. I'll investigate this soon.

Netdata documentation about streaming.

Netdata also added some machine learning anomaly detection, it's simple and doesn't use many resources or require a GPU, it only builds statistical models to be able to report if some metrics have an unusual trend. It takes some time to gather enough data, and after a few days it's starting to work.

3. Installing Netdata on NixOS §

As usual, it's simple, add this to your NixOS configuration and reconfigure the system.

  services.netdata = {
    enable = true;

    config = {
      global = {
        # uncomment to reduce memory to 32 MB
        #"page cache size" = 32;

        # update interval
        "update every" = 15;
      };
      ml = {
        # enable machine learning
        "enabled" = "yes";
      };
    };
  };

You should have Netdata dashboard available on http://localhost:19999 .

3.1. Streaming mode §

Here is a simple configuration on NixOS to connect a headless node without persistency to send all on a main Netdata server storing data but also displaying them.

You need to generate an UUID with uuidgen, replace UUID in the text with the result. It can be per system or shared by multiple Netdata instances.

My networks are 10.42.42.0/24 and 10.43.43.0/24, I'll allow everything matching 10.* on the receiver, I don't open port 19999 on a public interface.

3.1.1. Senders §

  services.netdata.enable = true;
  services.netdata.config = {
      global = {
          "default memory mode" = "none"; # can be used to disable local data storage
      };
  };
  services.netdata.configDir = {
    "stream.conf" = pkgs.writeText "stream.conf" ''
      [stream]
        enabled = yes
        destination = 10.42.42.42:19999
        api key = UUID
      [UUID]
        enabled = yes
    '';
  };

3.1.2. Receiver §

  networking.firewall.allowedTCPPorts = [19999];
  services.netdata.enable = true;
  services.netdata.configDir = {
    "stream.conf" = pkgs.writeText "stream.conf" ''
      [UUID]
        enabled = yes
        default history = 3600
        default memory mode = dbengine
        health enabled by default = auto
        allow from = 10.*
    '';
  };

4. Netdata cloud §

Netdata company started a "cloud" offer that is free, but they plan to keep it free but also propose more services for paying subscribers. The free plan is just a convenience to see metrics from multiple nodes at the same place, they don't store any metrics apart metadata (server name, OS version, kernel, etc..), when you look at your metrics, they just relay from your server to your web browser without storing the data.

The free cloud plan offers a correlating feature, but I still didn't have the opportunity to try it, and also email alerting when an alarm is triggered.

Netdata cloud website

Netdata cloud data privacy information

4.1. Adding a node §

The official way to connect a Netdata agent to the Netdata cloud is to use a script downloaded on the internet and run it with some parameter.

Connecting a Linux agent

I strongly dislike this method as I'm not a huge fan of downloading script to run as root that are not provided by my system.

When you want to add a new node, you will be given a long command line and a token, keep that token somewhere. NixOS Netdata package offers a script named netdata-claim.sh (which seems to be part of Netdata source code) that will generate a pair of RSA keys, and look for the token in a file.

Netdata data page: Add a node

Once you got the token, we will claim it to associate it to a node:

  1. create /var/lib/netdata/cloud.d/token and write the token in it
  2. run nix-shell -p netdata --run "netdata-claim.sh" as root
  3. your node should be registered in Netdata cloud

5. Conclusion §

Netdata is really a wonderful tool, ideally I'd like it to replace all the Grafana + storage + agent stack, but it doesn't provide persistent centralized storage compatible with its dashboard. I'm going to experiment with their Netdata cloud service, I'm not sure if it would add value for me, and while they have a very correct data privacy policy, I prefer to self-host everything.

Explaining modern server monitoring stacks for self-hosting

Written by Solène, on 11 September 2022.
Tags: #nixos #monitoring #efficiency #nocloud

Comments on Fediverse/Mastodon

1.!/bin/introduction §

Hello 👋🏻, it's been a long time I didn't have to take a look at monitoring servers. I've set up a Grafana server six years ago, and I was using Munin for my personal servers.

However, I recently moved my server to a small virtual machine which has CPU and memory constraints (1 core / 1 GB of memory), and Munin didn't work very well. I was curious to learn if the Grafana stack changed since the last time I used it, and YES.

There is that project named Prometheus which is used absolutely everywhere, it was time for me to learn about it. And as I like to go against the flow, I tried various changes to the industry standard stack by using VictoriaMetrics.

In this article, I'm using NixOS configuration for the examples, however it should be obvious enough that you can still understand the parts if you don't know anything about NixOS.

2. The components §

VictoriaMetrics is a Prometheus drop-in replacement that is a lot more efficient (faster and use less resources), which also provides various API such as Graphite or InfluxDB. It's the component storing data. It comes with various programs like VictoriaMetrics agent to replace various parts of Prometheus.

Update: a dear reader shown me VictoriaMetrics can be used to scrape remote agents without the VictoriaMetrics agent, this reduce the memory usage and configuration required.

VictoriaMetrics official website

VictoriaMetrics documentation "how to scrape prometheus exporters such as node exporter"

Prometheus is a time series database, which also provide a collecting agent named Node Exporter. It's also able to pull (scrape) data from remote services offering a Prometheus API.

Prometheus official website

Node Exporter GitHub page

NixOS is an operating system built with the Nix package manager, it has a declarative approach that requires to reconfigure the system when you need to make a change.

NixOS official website

Collectd is a agent gathering metrics from the system and sending it to a remote compatible database.

Collectd official website

Grafana is a powerful Web interface pulling data from time series databases to render them under useful charts for analysis.

Grafana official website

Node exporter full Grafana dashboard

3. Setup 1: Prometheus server scraping remote node_exporter §

In this setup, a Prometheus server is running on a server along with Grafana, and connects to remote servers running node_exporter to gather data.

Running it on my server, Grafana takes 67 MB, the local node_exporter 12.5 MB and Prometheus 63 MB.

USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
grafana   837975  0.1  6.7 1384152 67836 ?       Ssl  01:19   1:07 grafana-server
node-ex+  953784  0.0  1.2 941292 12512 ?        Ssl  16:24   0:01 node_exporter
prometh+  983975  0.3  6.3 1226012 63284 ?       Ssl  17:07   0:00 prometheus
Setup 1 diagram
Setup 1 diagram
  • model: pull, Prometheus is connecting to all servers

3.1. Pros §

  • it's the industry standard
  • can use the "node exporter full" Grafana dashboard

3.2. Cons §

  • uses memory
  • you need to be able to reach all the remote nodes

3.3. Server §

{
  services.grafana.enable = true;
  services.prometheus.exporters.node.enable = true;

  services.prometheus = {
    enable = true;
    scrapeConfigs = [
      {
        job_name = "kikimora";
        static_configs = [
          {targets = ["10.43.43.2:9100"];}
        ];
      }
      {
        job_name = "interbus";
        static_configs = [
          {targets = ["127.0.0.1:9100"];}
        ];
      }
    ];
  };
}

3.4. Client §

{
  networking.firewall.allowedTCPPorts = [9100];
  services.prometheus.exporters.node.enable = true;
}

4. Setup 2: VictoriaMetrics + node-exporter in pull model §

In this setup, a VictoriaMetrics server is running on a server along with Grafana. A VictoriaMetrics agent is running locally to gather data from remote servers running node_exporter.

Running it on my server, Grafana takes 67 MB, the local node_exporter 12.5 MB, VictoriaMetrics 30 MB and its agent 13.8 MB.

USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
grafana   837975  0.1  6.7 1384152 67836 ?       Ssl  01:19   1:07 grafana-server
node-ex+  953784  0.0  1.2 941292 12512 ?        Ssl  16:24   0:01 node_exporter
victori+  986126  0.1  3.0 1287016 30052 ?       Ssl  18:00   0:03 victoria-metric
root      987944  0.0  1.3 1086276 13856 ?       Sl   18:30   0:00 vmagent
Setup 2 diagram
Setup 2 diagram
  • model: pull, VictoriaMetrics agent is connecting to all servers

4.1. Pros §

  • can use the "node exporter full" Grafana dashboard
  • lightweight and more performant than Prometheus

4.2. Cons §

  • you need to be able to reach all the remote nodes

4.3. Server §

let
  configure_prom = builtins.toFile "prometheus.yml" ''
    scrape_configs:
    - job_name: 'kikimora'
      stream_parse: true
      static_configs:
      - targets:
        - 10.43.43.1:9100
    - job_name: 'interbus'
      stream_parse: true
      static_configs:
      - targets:
        - 127.0.0.1:9100
  '';
in {
  services.victoriametrics.enable = true;
  services.grafana.enable = true;

  systemd.services.export-to-prometheus = {
    path = with pkgs; [victoriametrics];
    enable = true;
    after = ["network-online.target"];
    wantedBy = ["multi-user.target"];
    script = "vmagent -promscrape.config=${configure_prom} -remoteWrite.url=http://127.0.0.1:8428/api/v1/write";
  };
}

4.4. Client §

{
  networking.firewall.allowedTCPPorts = [9100];
  services.prometheus.exporters.node.enable = true;
}

5. Setup 3: VictoriaMetrics + node-exporter in push model §

In this setup, a VictoriaMetrics server is running on a server along with Grafana, on each server node_exporter and VictoriaMetrics agent are running to export data to the central VictoriaMetrics server.

Running it on my server, Grafana takes 67 MB, the local node_exporter 12.5 MB, VictoriaMetrics 30 MB and its agent 13.8 MB, which is exactly the same as the setup 2, except the VictoriaMetrics agent is running on all remote servers.

USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
grafana   837975  0.1  6.7 1384152 67836 ?       Ssl  01:19   1:07 grafana-server
node-ex+  953784  0.0  1.2 941292 12512 ?        Ssl  16:24   0:01 node_exporter
victori+  986126  0.1  3.0 1287016 30052 ?       Ssl  18:00   0:03 victoria-metric
root      987944  0.0  1.3 1086276 13856 ?       Sl   18:30   0:00 vmagent
Setup 3 diagram
Setup 3 diagram
  • model: push, each agent is connecting to the VictoriaMetrics server

5.1. Pros §

  • can use the "node exporter full" Grafana dashboard
  • memory efficient
  • can bypass firewalls easily

5.2. Cons §

  • you need to be able to reach all the remote nodes
  • more maintenance as you have one extra agent on each remote
  • may be bad for security, you need to allow remote servers to write to your VictoriaMetrics server

5.3. Server §

{
  networking.firewall.allowedTCPPorts = [8428];
  services.victoriametrics.enable = true;
  services.grafana.enable = true;
  services.prometheus.exporters.node.enable = true;
}

5.4. Client §

let
  configure_prom = builtins.toFile "prometheus.yml" ''
    scrape_configs:
    - job_name: '${config.networking.hostName}'
      stream_parse: true
      static_configs:
      - targets:
        - 127.0.0.1:9100
  '';
in {
  services.prometheus.exporters.node.enable = true;
  
  systemd.services.export-to-prometheus = {
    path = with pkgs; [victoriametrics];
    enable = true;
    after = ["network-online.target"];
    wantedBy = ["multi-user.target"];
    script = "vmagent -promscrape.config=${configure_prom} -remoteWrite.url=http://victoria-server.domain:8428/api/v1/write";
  };
}

6. Setup 4: VictoriaMetrics + Collectd §

In this setup, a VictoriaMetrics server is running on a server along with Grafana, servers are running Collectd sending data to VictoriaMetrics graphite API.

Running it on my server, Grafana takes 67 MB, VictoriaMetrics 30 MB and Collectd 172 kB (yes).

USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
grafana   837975  0.1  6.7 1384152 67836 ?       Ssl  01:19   1:07 grafana-server
victori+  986126  0.1  3.0 1287016 30052 ?       Ssl  18:00   0:03 victoria-metric
collectd  844275  0.0  0.0 610432   172 ?        Ssl  02:07   0:00 collectd
Setup 4 diagram
Setup 4 diagram
  • model: push, VictoriaMetrics receives data from the Collectd servers

6.1. Pros §

  • super memory efficient
  • can bypass firewalls easily

6.2. Cons §

  • you can't use the "node exporter full" Grafana dashboard
  • may be bad for security, you need to allow remote servers to write to your VictoriaMetrics server
  • you need to configure Collectd for each host

6.3. Server §

The server requires VictoriaMetrics to run exposing its graphite API on ports 2003.

Note that in Grafana, you will have to escape "-" characters using "\-" in the queries. I also didn't find a way to automatically discover hosts in the data to use variables in the dashboard.

UPDATE: Using write_tsdb exporter in collectd, and exposing a TSDB API with VictoriaMetrics, you can set a label to each host, and then use the query "label_values(status)" in Grafana to automatic discover hosts.

{
  networking.firewall.allowedTCPPorts = [2003];
  services.victoriametrics = {
    enable = true;
    extraOptions = [
      "-graphiteListenAddr=:2003"
    ];
  };
  services.grafana.enable = true;
  
}

6.4. Client §

We only need to enable Collectd on the client:

{
  services.collectd = {
    enable = true;
    autoLoadPlugin = true;
    extraConfig = ''
      Interval 30
    '';
    plugins = {
      "write_graphite" = ''
        <Node "${config.networking.hostName}">
          Host "victoria-server.fqdn"
          Port "2003"
          Protocol "tcp"
          LogSendErrors true
          Prefix "collectd_"
        </Node>
      '';
      cpu = ''
        ReportByCpu false
      '';
      memory = "";
      df = ''
        Mountpoint "/"
        Mountpoint "/nix/store"
        Mountpoint "/home"
        ValuesPercentage True
        ValuesAbsolute False
      '';
      load = "";
      uptime = "";
      swap = ''
        ReportBytes false
        ReportIO false
        ValuesPercentage true
      '';
      interface = ''
        ReportInactive false
      '';
    };
  };
}

7. Trivia §

The first section named #!/bin/introduction" is on purpose and not a mistake. It felt super fun when I started writing the article, and wanted to keep it that way.

The Collectd setup is the most minimalistic while still powerful, but it requires lot of work to make the dashboards and configure the plugins correctly.

The setup I like best is the setup 2.

Bento 1.0.0 released

Written by Solène, on 09 September 2022.
Tags: #nixos #deployment #bento

Comments on Fediverse/Mastodon

1. Introduction §

Bento 1.0.0 is alive!

GitHub Bento project

Tildegit mirror

Compared to the previous news, it received

  • bento is now a single script, easy to package and add to $PATH. Before that it was a set of scripts with a shared shell files with functions in it, not very practical…
  • the hosts directory can contain directories with flakes in it, that may contain multiple hosts, it’s now handled. If there is no flake in it, then the machine is named after the directory name
  • bento supports rollbacks, if something is wrong during the deployment then the previous system is roll backed
  • enhancement to the status output when you don't have a flaked system, as build are not reproducible (without efforts) we can't really compare local and remote builds
   machine   local version   remote version              state                                     time
   -------       ---------      -----------      -------------                                     ----
  interbus      non-flakes      1dyc4lgr 📌      up to date 💚                              (build 11s)
  kikimora        996vw3r6      996vw3r6 💚    sync pending 🚩       (build 5m 53s) (new config 2m 48s)
       nas        r7ips2c6      lvbajpc5 🛑 rebuild pending 🚩       (build 5m 49s) (new config 1m 45s)
      t470        b2ovrtjy      ih7vxijm 🛑      rollbacked 🔃                           (build 2m 24s)
        x1        fcz1s2yp      fcz1s2yp 💚      up to date 💚                           (build 2m 37s)
  • network measurements shown that polling for configuration changes costs 5.1 kB IN and OUT
  • many checks has been added when something is going wrong

2. On step §

It's a huge milestone for me, I thought it would be too much work to get there, but in one week and 441 lines of shell, bento is a real thing.

Video - talk about NixOS deployments tools

Written by Solène, on 09 September 2022.
Tags: #nixos #deployment

Comments on Fediverse/Mastodon

1. Intro §

At work, we have a weekly "knowledge sharing" meeting, yesterday I talked about the state of NixOS deployments tools.

I had to look at all the tools we currently have at hand before starting my own, so it made sense to share all what I found.

This is a real topic, it doesn't make much sense to use regular sysadmins tools like ansible / puppet / salt etc... on NixOS, we need specific tools, and there is currently a bunch of them, and it can be hard to decide which one to use.

YouTube video: A journey into the world of NixOS deployment tools

Text file used for the presentation

Git - How to prevent a branch to be pushed

Written by Solène, on 08 September 2022.
Tags: #git #versioning #unix

Comments on Fediverse/Mastodon

1. Introduction §

I was looking for a simple way to prevent pushing a specific git branch. A few searches on the Internet didn't give me good results, so let me share a solution.

2. Hooks §

Hooks are scripts run by git at a specific time, you have the "pre-" hooks before an action, and "post-" hooks after an action.

We need to edit the hook "pre-push" that happens at push time, before the real push action taking place.

Edit or create the file .git/hooks/pre-push:

#!/bin/sh

branch="$(git branch --show-current)"

if [ "${branch}" = "private" ]
then
    echo "Pushing to the branch ${branch} is forbidden"
    exit 1
fi

Mark the file as executable, otherwise it won't work.

In this example, if you run "git push" while on the branch "private", the process will be aborted.

NixOS Bento: now able to compare local and remote NixOS version

Written by Solène, on 06 September 2022.
Tags: #bento #nixos #nix

Comments on Fediverse/Mastodon

1. Bento §

Project update: the report is now able to compare if the remote server is using the NixOS version we built locally. This is possible as NixOS builds are reproducible, I get the same result on the server and the remote system.

The tool is getting in a better shape, the code received extra checks in a lot of place.

A bit later (blog post update), I added the possibility to trigger the update from the user.

Bento git project repository

2. Listening to socket §

With systemd it's possible to trigger a command upon connecting on a socket, I made bento systemd service to listen on port TCP/51337, a connection would start the service "bento-update.service", and display the output to the TCP client.

This totally works in the web browser, it's now possible to create a bookmark that just starts the update and give instant feedback about the update process. This will be particularly useful in case of a debug phone session to ask the remote person to trigger an update on their side instead of waiting for a timer.

3. Status display demo §

It is now possible to differenciate the "not up to date" state into two categories:

  • the bento scripts were updated but not NixOS version change, this is called "sync pending". Changes could be distributing the updating file to give a new address for the remote server, so we can ensure they all received it.
  • the local NixOS version differs from the remote version, a rebuild is required, thus it's called "rebuild pending"

The "sync pending" is very fast, it only need to copy the files, but won't rebuild anything.

   machine   local version   remote version              state                                     time
   -------       ---------      -----------      -------------                                     ----
  kikimora        996vw3r6      996vw3r6 💚    sync pending 🚩       (build 5m 53s) (new config 2m 48s)
       nas        r7ips2c6      lvbajpc5 🛑 rebuild pending 🚩       (build 5m 49s) (new config 1m 45s)
      t470        ih7vxijm      ih7vxijm 💚      up to date 💚                           (build 2m 24s)
        x1        fcz1s2yp      fcz1s2yp 💚      up to date 💚                           (build 2m 37s)

NixOS Bento: new reporting feature

Written by Solène, on 05 September 2022.
Tags: #bento #nixos #nix

Comments on Fediverse/Mastodon

1. Bento §

Bento received a new feature, it is now able to report if the remote hosts are up-to-date, how much time passed since their last update, and if they are not up-to-date, how long passed since the configuration change.

Bento git project repository

As Bento is using SFTP, it's possible to deposit information on the central server, I'm currently using log files from the builds, and compare this date to the date of the configuration.

This will be very useful to track deployments across the fleet. I plan to also check the version expected for a host and make them report their version after an update, this should possible for flakes system at least.

Asciinema demonstration (was done during development, doesn't contain report features)

2. Demonstration §

I pushed a new version affecting all hosts on the SFTP server, and run the status report regularly.

This is the output 15 seconds after making the changes available.

status of kikimora  not up to date 🚩 (last_update 15m 6s ago) (since config change 15s ago)
status of      nas  not up to date 🚩 (last_update 12m  ago) (since config change 15s ago)
status of     t470  not up to date 🚩 (last_update 16m 9s ago) (since config change 15s ago)
status of       x1  not up to date 🚩 (last_update 16m 24s ago) (since config change 14s ago)

This is the output after two systems picked up the changes and reported a success.

status of kikimora  not up to date 🚩 (last_rebuild 16m 46s ago) (since config change 1m 55s ago)
status of      nas      up to date 💚 (last_rebuild 8s ago)
status of     t470  not up to date 🚩 (last_rebuild 17m 49s ago) (since config change 1m 55s ago)
status of       x1      up to date 💚 (last_rebuild 4s ago)

This is the output after all systems reported a success.

status of kikimora  up to date 💚 (last_rebuild 0s ago)
status of      nas  up to date 💚 (last_rebuild 1m 24s ago)
status of     t470  up to date 💚 (last_rebuild 1m 2s ago)
status of       x1  up to date 💚 (last_rebuild 1m 20s ago)

Managing a fleet of NixOS Part 3 - Welcome to Bento

Written by Solène, on 04 September 2022.
Tags: #bento #nixos #nix

Comments on Fediverse/Mastodon

1. Introducing Bento 🥳 §

I finally wrote an implementation for the NixOS fleet management, it's called Bento.

Bento git project repository

2. Features §

  • secure 🛡️: each client can only access its own configuration files (ssh authentication + sftp chroot)
  • efficient 🏂🏾: configurations can be built on the central management server to serve binary packages if it is used as a substituters by the clients
  • organized 💼: system administrators have all configurations files in one repository to easy management
  • peace of mind 🧘🏿: configurations validity can be verified locally by system administrators
  • smart 💡: secrets (arbitrary files) can (soon) be deployed without storing them in the nix store
  • robustness in mind 🦾: clients just need to connect to a remote ssh, there are many ways to bypass firewalls (corkscrew, VPN, Tor hidden service, I2P, ...)
  • extensible 🧰 🪡: you can change every component, if you prefer using GitHub repositories to fetch configuration files instead of a remote sftp server, you can change it
  • for all NixOS 💻🏭📱: it can be used for remote workstations, smartphones running NixoS, servers in a datacenter

3. Evolutions §

The project is still bare right now, I started it yesterday and I have many ideas to improve it:

  • package it to provide commands in $PATH instead of adding scripts to your config repository
  • add a rollback features in case an upgrade is losing connectivity
  • upgrades can depose a log file in the remote sftp server
  • upgrades could be triggered by the user by accessing a local socket, like opening a web page in a web browser to trigger it, if it returns output that'd be better
  • provide more useful modules in the utility nix file (automatically use the host as a binary cache for instance)
  • have a local information how to ssh to the client to ease the rebuild trigger (like a SSH file containing ssh command line)
  • a way to tell a client (when using flakes) to try to update flakes every time even if no configuration changed, to keep them up to date

Managing a fleet of NixOS Part 2 - A KISS design

Written by Solène, on 03 September 2022.
Tags: #bento #nixos #nix

Comments on Fediverse/Mastodon

1. Introduction §

Let's continue my series trying to design a NixOS fleet management.

Yesterday, I figured out 3 solutions:

  1. periodic data checkout
  2. pub/sub - event driven
  3. push from central management to workstations

I retained solutions 2 and 3 only because they were the only providing instantaneous updates. However, I realize we could have a hybrid setup because I didn't want to let the KISS solution 1 away.

In my opinion, the best we can create is a hybrid setup of 1 and 3.

2. A new solution §

In this setup, all workstations will connect periodically to the central server to look for changes, and then trigger a rebuild. This simple mechanism can be greatly extended per-host to fit all our needs:

  • periodicity can be configured per-host
  • the rebuild service can be triggered on purpose manually by the user clicking on a button on their computer
  • the rebuild service can be triggered on purpose manually by a remote sysadmin having access to the system (using a VPN), this partially implements solution 3
  • the central server can act as a binary cache if configured per-host, it can be used to rebuild each configuration beforehand to avoid rebuilding on the workstations, this is one of Cachix Deploy arguments
  • using ssh multiplexing, remote checks for the repository can have a reduced bandwidth usage for maximum efficiency
  • a log of the update can be sent to the sftp server
  • the sftp server can be used to check connectivity and activate a rollback to previous state if you can't reach it anymore (like "magic rollback" with deploy-rs)
  • the sftp server is a de-facto available target for potential backups of the workstation using restic or duplicity

The mechanism is so simple, it could be adapted to many cases, like using GitHub or any data source instead of a central server. I will personally use this with my laptop as a central system to manage remote servers, which is funny as my goal is to use a server to manage workstations :-)

3. File access design §

One important issue I didn't approach in the previous article is how to distribute the configuration files:

  • each workstation should be restricted to its own configuration only
  • how to send secrets, we don't want them in the nix-store
  • should we use flakes or not? Better to have the choice
  • the sysadmin on the central server should manage everything in a single git repository and be able to use common configuration files across the hosts

Addressing each of these requirements is hard, but in the end I've been able to design a solution that is simple and flexible:

Design pattern for managing users
Design pattern for managing users

The workflow is the following:

  • the sysadmin writes configuration files for each workstation in a dedicated directory
  • the sysadmin creates a symlink to a directory of common modules in each workstation directories
  • after a change, the sysadmin runs a program that will copy each workstation configuration into a directory in a chroot, symlinks have to be resolved
  • OPTIONAL: we can dry-build each host configuration to check if they work
  • OPTIONAL: we can build each host configuration to provide them as a binary cache

The directory holding configuration is likely to have a flake.nix file (can be a symlink to something generic), a configuration file, a directory with a hierarchy of files to copy as-this in the system to copy things like secrets or configuration files not managed by NixOS, and a symlink to a directory of nix files factorized for all hosts.

The NixOS clients will connect to their dedicated users with ssh using their private key, this allows to separate each client on the host system and restrict what they can access using the SFTP chroot feature.

A diagram of a real world case with 3 users would look like this:

Real world example with 3 users
Real world example with 3 users

4. Work required for the implementation §

The setup is very easy and requires only a few components:

  • a program to translates the configuration repository into separate directories in the chroot
  • some NixOS configuration to create the SFTP chroots, we just need to create a nix file with a list of pair of values containing "hostname" "ssh-public-key" for each remote host, this will automate the creation of the ssh configuration file
  • a script on the user side that connects and look for changes and run nixos-rebuild if something changes, maybe rclone could be used to "sync" over SFTP efficiently
  • a systemd timer for the user script
  • a systemd socket triggering the user script, so people can just open http://localhost:9999 to trigger the socket and forcing the update, create a bookmark named "UPDATE MY MACHINE" on the user system

5. Conclusion §

I absolutely love this design, it's simple, and each piece can easily be replaced to fit one's need. Now, I need to start writing all the bits to make it real, and offer it to the world 🎉.

There is a NixOS module named autoUpgrade, I'm aware of its existence, but while it's absolutely perfect for the average user workstation or server, it's not practical for managing a fleet of NixOS efficiently.

How to host a local front-end for Reddit / YouTube / Twitter on NixOS

Written by Solène, on 02 September 2022.
Tags: #nixos #privacy

Comments on Fediverse/Mastodon

1. Introduction §

I'm not a consumer of proprietary social networks, but sometimes I have to access content hosted there, and in that case I prefer to use a front-end reimplementation of the service.

These front-ends are network services that acts as a proxy to the proprietary service, and offer a different interface (usually cleaner) and also remove tracking / ads.

In your web browser, you can use the extension Privacy Redirect to automatically be redirected to such front-ends. But even better, you can host them locally instead of using public instances that may be unresponsive, on NixOS it's super easy.

We are going to see how to deploy them on NixOS.

Privacy Redirect GitHub project page

libreddit GitHub project page: Reddit front-end

Invidious project website: YouTube front-end

nitter GitHub project page: Twitter front-end

2. Deployment §

As September 2022, libreddit, invidious and nitter have NixOS modules to manage them.

The following pieces of code can be used in your NixOS configuration file (/etc/nixos/configuration.nix as the default location) before running "nixos-rebuild" to use the newer configuration.

I focus on running the services locally and not expose them on the network, thus you will need a bit more configuration to add HTTPS and tune the performance if you need more users.

2.1. Libreddit §

We will use the container and run it with podman, a docker alternative. The service takes only a few megabytes to run.

The service is exposed on http://127.0.0.1:12344

  services.libreddit = {
      address = "127.0.0.1";
      port = 12344;
  };

2.2. Invidious §

This is using the NixOS module.

The service is exposed on http://127.0.0.1:12345

  services.invidious = {
      enable = true;
      nginx.enable = false;
      port = 12345;

      # if you want to disable recommended videos
      settings = {
        default_user_preferences = {
          "related_videos" = false;
        };
      };
  };

2.3. Nitter §

This is using the NixOS module.

The service is exposed on http://127.0.0.1:12346

  services.nitter = {
      enable = true;
      server.port = 12346;
      server.address = "127.0.0.1";
  };

3. Privacy redirect §

By default, the extension will pick a random public instance, you can configure it per service to use your local instance.

4. Conclusion §

I very enjoy these front-ends, they draw a lot less resources when browsing these websites. I prefer to run them locally for performance reasons.

If you run such instances on your local computer, this doesn't help with regard to privacy. If you care about privacy, you should use public instances, or host your own public instances so many different users are behind the same service and this makes profiling harder. But if you want to host such instance, you may need to tweak the performance, and add a reverse proxy and a valid TLS certificate.

Managing a fleet of NixOS Part 1 - Design choices

Written by Solène, on 02 September 2022.
Tags: #bento #nixos #nix

Comments on Fediverse/Mastodon

1. Introduction §

I have a grand project in my mind, and I need to think about it before starting any implementation. The blog is a right place for me to explain what I want to do and the different solutions.

It's related to NixOS. I would like to ease the management of a fleet of NixOS workstations that could be anywhere.

This could be useful for companies using NixOS for their employees, to manage all the workstations remotely, but also for people who may manage NixOS systems in various places (cloud, datacenter, house, family computers).

In this central management, it makes sense to not have your users with root access, they would have to call their technical support to ask for a change, and their system could be updated quickly to reflect the request. This can be super useful for remote family computers when they need an extra program not currently installed, and that you took the responsibility of handling your system...

With NixOS, this setup totally makes sense, you can potentially reproduce users bugs as you have their configuration, stage new changes for testing, and users can roll back to a previous working state in case of big regression.

Cachix company made it possible before I figure a solution. It's still not late to propose an open source alternative.

Cachix Deploy

2. Defining the project §

The purpose of this project is to have a central management system on which you keep the configuration files for all the NixOS around, and allow the administrator to make the remote NixOS to pick up the new configuration as soon as possible when required.

We can imagine three different implementations at the highest level:

  • a scheduled job on each machine looking for changes in the source. The source could be a git repository, a tarball or anything that could be used to carry the configuration.
  • NixOS systems could connect to something like a pub/sub and wait for an event from the central management to trigger a rebuild, the event may or not contain information / sources.
  • the central management system could connect to the remote NixOS to trigger the build / push the build

These designs have all pros and cons. Let's see them more in details.

2.1. Solution 1 - Scheduled job §

In this scenario, The NixOS system would use a cron or systemd timer to periodically check for changes and trigger the update.

2.1.1. Pros §

  • low maintenance
  • could interactively ask the user when they want to upgrade if not now

2.1.2. Cons §

  • may not run at all if the system is not up at the correct time, or could be run at a delayed time depending on situation
  • can't force an update as soon as possible
  • not really bandwidth effective if you often poll
  • no feedback from the central management about who made/receive the update (except by adding a call to the server?)

2.2. Solution 2 - Remote systems are listening for changes (publisher / subscriber) §

In this scenario, the NixOS system would always be connected to the central management, using some kind of protocol like MQTT, BOCH or similar.

2.2.1. Pros §

  • you know which systems are up
  • events from central management are instantaneous and should wait for an acknowledgment
  • updates should propagate very quickly
  • could interactively ask the user when they want to upgrade if not now

2.2.2. Cons §

  • this can lead to privacy issue as you know when each host is connected
  • this adds complexity to the server
  • this adds complexity on each client
  • firewalls usually don't like long-lived connections, HTTPS based solution would help bypass firewalls

2.3. Solution 3 - The central management pushes the updates to the remote systems §

In this scenario, the NixOS system would be reachable over a protocol allowing to run commands like SSH. The central management system would run a remote upgrade on it, or push the changes using tools like deploy-rs, colmena, morph or similar...

Awesome-nix list: deployment-tools

2.3.1. Pros §

  • update is immediate
  • SSH could be exposed over TOR or I2P for maximum firewall bypassing capability

2.3.2. Cons §

  • offline systems may be complicated to update, you would need to try to connect to them often until they are reachable
  • you can connect to the remote machine and potentially spy the user. In the alternatives above, you can potentially achieve the same by reconfiguring the computer to allow this, but it would have to be done on purpose

3. Making a choice §

I tried to state the pros and cons of each setup, but I can't see a clear winner. However, I'm not convinced by the Solution 1 as you don't have any feedback or direct control on the systems, I prefer to abandon it.

The Solutions 2 and 3 are still in the competition, we basically ended with a choice between a PUSH and a PULL workflow.

4. Conclusion §

In order to choose between 2 and 3, I will need to experiment with the Solution 2 technologies as I never used them (MQTT, RabbitMQ, BOCH etc…).

NixOS specific feature: specialisations

Written by Solène, on 29 August 2022.
Tags: #nixos #nix #tweag

Comments on Fediverse/Mastodon

1. Credits §

This blog post is a republication of the article I published on my employer's blog under CC BY 4.0. I'm grateful to be allowed to publish NixOS related content there, but also to be able to reuse it here!

License CC by 4.0

Original publication place: Tweag I/O - NixOS Specialisations

After the publication of the original post, the NixOS wiki got updated to contain most of this content, I added some extra bits for the specific use case of "options for the non-specialisation that shouldn't be inherited by specialisations" that wasn't convered in this text.

NixOS wiki: Specialisation

2. Introduction §

I often wished to be able to define different boot entries for different uses of my computer, be it for separating professional and personal use, testing kernels or using special hardware. NixOS has a unique feature that solves this problem in a clever way — NixOS specialisations.

A NixOS specialisation is a mechanism to describe additional boot entries when building your system, with specific changes applied on top of your non-specialised configuration.

3. When do you need specialisations §

You may have hardware occasionally connected to your computer, and some of these devices may require incompatible changes to your day-to-day configuration. Specialisations can create a new boot entry you can use when starting your computer with your specific hardware connected. This is common for people with external GPUs (Graphical Processing Unit), and the reason why I first used specialisations.

With NixOS, when I need my external GPU, I connect it to my computer and simply reboot my system. I choose the eGPU specialisation in my boot menu, and it just works. My boot menu looks like the following:

NixOS specialisation shown in Grub
NixOS specialisation shown in Grub

You can also define a specialisation which will boot into a different kernel, giving you a safe opportunity to try a new version while keeping a fallback environment with the regular kernel.

We can push the idea further by using a single computer for professional and personal use. Specialisations can have their own users, services, packages and requirements. This would create a hard separation without using multiple operating systems. However, by default, such a setup would be more practical than secure. While your users would only exist in one specialisation at a time, both users’ data are stored on the same partition, so one user could be exploited by an attacker to reach the other user’s data.

In a follow-up blog post, I will describe a secure setup using multiple encrypted partitions with different passphrases, all managed using specialisations with a single NixOS configuration. This will be quite awesome :)

4. How to use specialisations §

As an example, we will create two specialisations, one having the user Chani using the desktop environment Plasma, and the other with the user Paul using the desktop environment Gnome. Auto login at boot will be set for both users in their own specialisations. Our user Paul will need an extra system-wide package, for example dune-release. Specialisations can use any argument that would work in the top-level configuration, so we are not limited in terms of what can be changed.

NixOS manual: Configuration options

If you want to try, add the following code to your configuration.nix file.

specialisation = {
  chani.configuration = {
    system.nixos.tags = [ "chani" ];
    services.xserver.desktopManager.plasma5.enable = true;
    users.users.chani = {
      isNormalUser = true;
      uid = 1001;
      extraGroups = [ "networkmanager" "video" ];
    };
    services.xserver.displayManager.autoLogin = {
      enable = true;
      user = "chani";
    };
  };

  paul.configuration = {
    system.nixos.tags = [ "paul" ];
    services.xserver.desktopManager.gnome.enable = true;
    users.users.paul = {
      isNormalUser = true;
      uid = 1002;
      extraGroups = [ "networkmanager" "video" ];
    };
    services.xserver.displayManager.autoLogin = {
      enable = true;
      user = "paul";
    };
    environment.systemPackages = with pkgs; [
      dune-release
    ];
  };
};

After applying the changes, run "nix-rebuild boot" as root. Upon reboot, in the GRUB menu, you will notice a two extra boot entries named “chani” and “paul” just above the last boot entry for your non-specialised system.

Rebuilding the system will also create scripts to switch from a configuration to another, specialisations are no exception.

Run "/nix/var/nix/profiles/system/specialisation/chani/bin/switch-to-configuration switch" to switch to the chani specialisation.

When using the switch scripts, keep in mind that you may not have exactly the same environment as if you rebooted into the specialisation as some changes may be only applied on boot.

5. Conclusion §

Specialisations are a perfect solution to easily manage multiple boot entries with different configurations. It is the way to go when experimenting with your system, or when you occasionally need specific changes to your regular system.

My BTRFS cheatsheet

Written by Solène, on 29 August 2022.
Tags: #btrfs #linux

Comments on Fediverse/Mastodon

1. Introduction §

I recently switched my home "NAS" (single disk!) to BTRFS, it's a different ecosystem with many features and commands, so I had to write a bit about it to remember the various possibilities...

BTRFS is an advanced file-system supported in Linux, it's somehow comparable to ZFS.

2. Layout §

A BTRFS file-system can be made of multiple disks and aggregated in mirror or "concatenated", it can be split into subvolumes which may have specific settings.

Snapshots and quotas are applying on subvolumes, so it's important to think beforehand when creating BTRFS subvolumes, one may want to use a subvolume for /home and for /var for most cases.

3. Snapshots / Clones §

It's possible to take an instant snapshot of a subvolume, this can be used as a backup. Snapshots can be browsed like any other directory. They exist in two flavors: read-only and writable. ZFS users will recognize writable snapshots as "clones" and read-only as regular ZFS snapshots.

Snapshots are an effective way to make a backup and rolling back changes in a second.

4. Send / Receive §

Raw filesystem can be sent / receive over network (or anything supporting a pipe) to allow incremental differences backup. This is a very effective way to do incremental backups without having to scan the entire file-system each time you run your backup.

5. Deduplication §

I covered deduplication with bees, but one can also use the program "duperemove" (works on XFS too!). They work a bit differently, but in the end they have the same purpose. Bees operates on the whole BTRFS file-system, duperemove operates on files, it's different use cases.

duperemove GitHub project page

Bees GitHub project page

6. Compression §

BTRFS supports on-the-fly compression per subvolume, meaning the content of each file is stored compressed, and decompressed on demand. Depending on the files, this can result in better performance because you would store less content on the disk, and it's less likely to be I/O bound, but also improve storage efficiency. This is really content dependent, you can't compress binary files like pictures/videos/music, but if you have a lot of text and sources files, you can achieve great ratios.

From my experience, compression is always helpful for a regular user workload, and newer algorithm are smart enough to not compress binary data that wouldn't yield any benefit.

There is a program named compsize that reports compression statistics for a file/directory. It's very handy to know if the compression is beneficial and to which extent.

compsize GitHub project page

7. Defragmentation §

Fragmentation is a real thing and not specific to Windows, it matters a lot for mechanical hard drive but not really for SSDs.

Fragmentation happens when you create files on your file-system, and delete them: this happens very often due to cache directories, updates and regular operations on a live file-system.

When you delete a file, this creates a "hole" of free space, after some time, you may want to gather all these small parts of free space to have big chunks of free space, this matters for mechanical disks has the physical location of data is tied to the raw performance. The defragmentation process is just physically reorganizing data to order files chunks and free space into continuous blocks.

Defragmentation can be used to force compression in a subvolume, like if you want to change the compression algorithm or enabled compression after saving the files.

The command line is: btrfs filesystem defragment

8. Scrubbing §

The scrubbing feature is one of the most valuable feature provided by BTRFS and ZFS. Each file in these file-system is associated with its checksum in some metadata index, this mean you can actually check each file integrity by comparing its current content with the checksum known in the index.

Scrubbing costs a lot of I/O and CPU because you need to compute the checksum of each file, but it's a guarantee for validating the stored data. In case of a corrupted file, if the file-system is composed of multiple disks (raid1 / raid5), it can be repaired from mirrored copies, it should work most of the time because such file corruption is often related to the drive itself, thus other drives shouldn't be affected.

Scrubbing can be started / paused / resumed, this is handy if you need to operate heavy I/O and you don't want the scrubbing process to increase time. While the scrub commands can take a device or a path, the path parameter is only used to find the related file-system, it won't just scrub the files in that directory.

The command line is: btrfs scrub

9. Rebalancing §

When you are aggregating multiple disks into one BTRFS file-system, files are written on a disk and some other files are written to the other, after a while, a disk may contain more data than the other.

The rebalancing purpose is to redistribute data across the disks more evenly.

10. Swap file §

You can't create a swap file on a BTRFS disk without a tweak. You must create the file in a directory with the special attribute "no COW" using "chattr +C /tmp/some_directory", then you can move it anywhere as it will inherit the "no COW" flag.

If you try to use a swap file with COW enabled on it, swapon will report a weird error, but you get more details in the dmesg output.

11. Converting §

It's possible to convert a ext2/3/4 file-system into BTRFS, obviously it must not be currently in use. The process can be rolled back until a certain point like defragmenting or rebalancing.

My blog workflow

Written by Solène, on 28 August 2022.
Tags: #blog #life

Comments on Fediverse/Mastodon

1. Introduction §

I occasionally get feedback about my blog, most of the time people are impressed with the rate of publication when they see the index page. I'm surprised it appears to be huge efforts, so I'll explain how I work on my blog.

2. Make it simple §

I rarely spend more than 40 minutes for a blog post, the average blog post takes 20 minutes. Most of them are sharing something I fiddled with in the day or week, so the topic is still fresh for me. The content of the short articles often consists of dumping a few commands / configuration I used, and write a bit of text around so the reader knows what to expect from the article, how to use the content and what's the point of the topic.

It's important to keep track of commands/configuration beforehand, so when I'm trying something new, and I think I could write about it, I keep a simple text file somewhere with the few commands I typed or traps I encountered.

3. Write ideas down §

My fear with regard to the blog is to be out of ideas, this would mean I would have boring days and I would have nothing to write about. Sometimes I look at packages repository updates in different Linux distribution, and look at the projects homepages for which the name is unknown to me. This is a fun way to discover new programs / tools and ideas. When something looks interesting, I write its name down somewhere and may come later to it. I also write down any idea that I could get in my mind about some unusual setup I would like to try, if I come to try it, it will certainly end up as a new blog entry to share my experience.

4. Don't think too much §

There are two rules for the blog: having fun and not lie/be accurate. Having fun? Yes, writing can be fun, organizing ideas and sharing them is a cool exercise. Watching the result is fun. Thinking too much about perfection is not fun.

I prefer to write most of the blog posts in one shot, quickly proofread and publish, and be done with it. If I save a blog post as a draft, I may not pick it up quickly, and it's not fun to get into the context to continue it. I occasionally abandon some posts because of that, or simply delete the file and start over.

Sometimes it happens I'm wrong when writing, in the case I prefer to remove the blog post than keeping it online at all cost. When I know a text is terribly outdated, I either remove it from the index or update it.

I don't use any analytics services and I do the blog for free, the only incentive is to have fun and to know it will certainly help someone to look for information.

5. The blog software §

This website is generated with a custom blog generator I wrote a few years ago (cl-yag), the workflow to use it is very simple it never fails to me:

  • write the blog file in the format I want, I currently use GemText but in the past some blog posts were written in org-mode, man page or markdown
  • add an entry in the list of articles, this contains all the metadata such as the title, date, tags and description for the open graph protocol (optional)
  • run "make"
  • wait 30s, it's online on HTTP / gopher / Gemini

The program is really fast despite it's generating all the files every time, the "raw text to HTML" content is cached and reused when wrapping the HTML in the blog layout, the Gemini version is published as-this, and the gopher files are processed by a Perl script rewriting all the links and wrapping the text (takes a while).

6. Quick proofreading §

Before publishing, I read my text and run a spellcheck program on it, my favorite is LanguageTool because it finds so many mistake versus aspell which only finds obvious typos.

7. More advanced blog posts §

It happens for some blog posts to be more elaborated, they often describe a complex setup and I need to ensure readers can reproduce all the steps and get the same results as me. This kind of blog post takes a day to write, they often require using a spare computer for experimentation, formatting, installing, downloading things, adjusting the text, starting over because I changed the text...

8. Conclusion §

If you want to publish a blog, my advices would be to have fun, to use a blog/website generator that doesn't get in your way, and to not be afraid to get started. It could be scary at first to publish texts on the wild Internet, and fear to be wrong, but it happens, accept it, learn from your mistakes and improve for the next time.

Local peer to peer binary cache with NixOS and Peerix

Written by Solène, on 25 August 2022.
Tags: #nixos #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

There is a cool project related to NixOS, called Peerix. It's a local daemon exposed as a local substituter (a server providing binary packages) that will discover other Peerix daemon on the local network, and use them as a source of binary packages.

Peerix is a simple way to reuse package already installed somewhere on the network instead of downloading it again. Packages delivered by Peerix substituters are signed with a private key, so you need to import each computer public key before being able to download/use their packages. While this can be cumbersome, this also mandatory to prevent someone on the network to spoof packages.

Perrix should be used wisely, because secrets in your store could be leaked to others.

Peerix GitHub page

2. Generating the keys §

First step is to generate a pair of keys for each computer using Peerix.

In the directory in which you have your configurations files, use the command:

nix-store --generate-binary-cache-key "peerix-$(hostname -s)" peerix-private peerix-public

3. Setup §

I will only cover the flakes installation on NixOS. Add the files peerix-private and peerix-public to git as this is a requirement to flakes.

NOTE: if you find a way to not add the private key to the store, I'll be glad to hear about your solution!

Add this input in your flake.nix file:

  peerix = {
    url = "github:cid-chan/peerix";
    inputs.nixpkgs.follows = "nixpkgs";
  };

Add "peerix" in the outputs parameters lile:

outputs = { eslf, nixpkgs, peerix}: {

And in the modules list of your configuration, add this:

  peerix.nixosModules.peerix
  {
    services.peerix = {
      enable = true;
      package = peerix.packages.x86_64-linux.peerix;
      openFirewall = true; # UDP/12304
      privateKeyFile = ./peerix-private;
      publicKeyFile =  ./peerix-public;
      publicKey = "THE CONTENT OF peerix-public FROM THE OTHER COMPUTER";
      # example # publicKey = "peerix-laptop:1ZjzxYFhzeRMni4CyK2uKHjgo6xy0=";
    };
  }

If you have multiple public keys to use, just add them with a space between each value.

Run "nix flake lock --update-input peerix" and you can now reconfigure your system.

4. How to use §

There is nothing special to do, when you update your system, or use nix-shell, the nix-daemon will use the local Peerix substituter first which will discover other Peerix instances if any, and will use them when possible.

You can check the logs of the peerix daemons using "journalctl -f -u peerix.service" on both systems.

5. Conclusion §

While Peerix isn't a big project, it has a lot of potential to help NixOS users with multiple computers to have a more efficient bandwidth usage, but also build time. If you build the same project (with same inputs) on your computers, you can pull the result from the other.

My RSS feed with HTML content is back

Written by Solène, on 23 August 2022.
Tags: #blog #cl-yag #nocloud

Comments on Fediverse/Mastodon

Dear readers, given the popular demand for a RSS feed with HTML in it (which used to be the default), I modified the code to generate a new RSS file using HTML for its content.

Here is a list of RSS feeds available on my blog:

RSS feed using the same raw content I'm using to write, available over HTTP

RSS feed using HTML, available over HTTP

RSS feed with gopher links and raw content, available over HTTP

RSS feed with gemini links and raw content, available over Gemini

RSS feed with gopher links and raw content, available over Gopher

I hope you find the one that fits the best for you. If you don't know, pick the first or second item in the list.

Using nix download bandwidth limit feature

Written by Solène, on 23 August 2022.
Tags: #bandwidth #nix #linux

Comments on Fediverse/Mastodon

1. Introduction §

I submitted a change to the nix package manager last week, and it got merged! It's now possible to define a bandwidth speed limit in the nix.conf configuration file.

Link to the GitHub pull request

This kind of limit setting is very important for users who don't have a fast Internet access, this allows the service to download packages while keep the network usable meanwhile.

Unfortunately, we need to wait for the next Nix version to be available to use it, fortunately it's easy to override a package settings to use the merge commit as a new version for nix.

Let's see how to configure NixOS to use a newer Nix version from git.

2. Setup §

On NixOS, we will override the nix package attributes to change its version and the according checksum.

We want the new option "download-speed" that takes a value for the kilobytes per second speed limit.

  nix.extraOptions = ''
    download-speed = 800
  '';
  nixpkgs.overlays = [
      (self: super:
      {
          nix = super.nix.overrideDerivation (oldAttrs: {
              name = "nix-unstable";
              src = super.fetchFromGitHub {
                  owner = "NixOS";
                  repo = "nix";
                  rev = "8d84634e26d6a09f9ca3fe71fcf9cba6e4a95107";
                  sha256 = "sha256-Z6weLCmdPZR044PIAA4GRlkQRoyAc0s5ASeLr+eK1N0=";
              };
          });
      })
  ];

Run "nixos-rebuild switch" as root, and voilà!

For non-NixOS, you can clone the git repository, checkout the according commit, build nix and install it on your system.

3. Going further §

Don't forget to remove that override setting once a new nix release will be published, or you will keep an older version of nix.

Minecraft performance improvement using the Sodium mod

Written by Solène, on 21 August 2022.
Tags: #minecraft #gaming #performance

Comments on Fediverse/Mastodon

1. Introduction §

This text is some kind of personal notes I save here, but it may be useful for some people. Don't expect high quality writing here 😀.

2. Modding §

Minecraft is quite slow and unoptimized, fortunately using the mod "Sodium", you get access to more advanced video settings that allow to reduce the computer power usage, or just make the game playable for older computers.

Sodium GitHub page

This requires PolyMC, a launcher for Minecraft which takes care of mods and other things. PolyMC is available on Linux and Windows.

PolyMC wiki

3. Setup §

In PolyMC:

  • create a new instance
  • pick your the minecraft version you want
  • below the minecraft versions, in "mod loader", choose "Fabric" and choose the version you want (the one with the star is recommended)
  • Press Ok
  • Modify the instance and choose Mods tab / right click on it to see the mods
  • Click on "Download mods"
  • Search "Sodium" in the list and click on it
  • Click on "Add mod for download"
  • Press OK
  • Close

Now, your Minecraft is using the Sodium mod, this allows greater choice within the "Video settings" like the Performance tab with more options.

Using systemd to make a Minecraft server to start on-demand and stop when it has no player

Written by Solène, on 20 August 2022.
Tags: #minecraft #nixos #systemd #automation

Comments on Fediverse/Mastodon

1. Introduction §

Sometimes it feels I have specific use cases I need to solve alone. Today, I wanted to have a local Minecraft server running on my own workstation, but only when someone needs it. The point was that instead of having a big java server running all the system, Minecraft server would start upon connection from a player, and would stop when no player remains.

However, after looking a bit more into this topic, it seems I'm not the only one who need this.

on-demand-minecraft: a project to automatically start a remote cloud server for whitelisted players

minecraft-server-hibernation: a wrapper that starts and stop a Minecraft server upon condition

As often, I prefer not to rely on third party tools when I can, so I found a solution to implement this using only systemd.

Even better, note that this method can work with any daemon given you can programmatically get the information whether to let it running or stop. In this example, I'm using Minecraft and the server stop is decided based on the player connecting fetch through rcon (a remote administration protocol).

2. The setup §

I made a simple graph to show the dependencies, there are many systemd components used to build this.

systemd dependency graph
systemd dependency graph

The important part is the use of the systemd proxifier, it's a command to accept a connection over TCP and relay it to another socket, meanwhile you can do things such as starting a server and wait for it to be ready. This is the key of this setup, without it, this couldn't be possible.

Basically, listen-minecraft.socket listens on the public TCP port and runs listen-minecraft.service upon connection. This service needs hook-minecraft.service which is responsible for stopping or starting minecraft, but will also make listen-minecraft.service wait for the TCP port to be open so the proxifier will relay the connection to the daemon.

Then, minecraft-server.service is started alongside with stop-minecraft.timer which will regularly run stop-minecraft.service to try to stop the server if possible.

3. Configuration §

I used NixOS to configure my on-demand Minecraft server. This is something you can do on any systemd capable system, but I will provide a NixOS example, it shouldn't be hard to translate to a regular systemd configuration files.

{ config, lib, pkgs, modulesPath, ... }:
let

  # check every 20 seconds if the server
  # need to be stopped
  frequency-check-players = "*-*-* *:*:0/20";

  # time in second before we could stop the server
  # this should let it time to spawn
  minimum-server-lifetime = 300;

  # minecraft port
  # used in a few places in the code
  # this is not the port that should be used publicly
  # don't need to open it on the firewall
  minecraft-port = 25564;

  # this is the port that will trigger the server start
  # and the one that should be used by players
  # you need to open it in the firewall
  public-port = 25565;

  # a rcon password used by the local systemd commands
  # to get information about the server such as the
  # player list
  # this will be stored plaintext in the store
  rcon-password = "260a368f55f4fb4fa";

  # a script used by hook-minecraft.service
  # to start minecraft and the timer regularly
  # polling for stopping it
  start-mc = pkgs.writeShellScriptBin "start-mc" ''
    systemctl start minecraft-server.service
    systemctl start stop-minecraft.timer
  '';

  # wait 60s for a TCP socket to be available
  # to wait in the proxifier
  # idea found in https://blog.developer.atlassian.com/docker-systemd-socket-activation/
  wait-tcp = pkgs.writeShellScriptBin "wait-tcp" ''
    for i in `seq 60`; do
      if ${pkgs.libressl.nc}/bin/nc -z 127.0.0.1 ${toString minecraft-port} > /dev/null ; then
        exit 0
      fi
      ${pkgs.busybox.out}/bin/sleep 1
    done
    exit 1
  '';

  # script returning true if the server has to be shutdown
  # for minecraft, uses rcon to get the player list
  # skips the checks if the service started less than minimum-server-lifetime
  no-player-connected = pkgs.writeShellScriptBin "no-player-connected" ''
    servicestartsec=$(date -d "$(systemctl show --property=ActiveEnterTimestamp minecraft-server.service | cut -d= -f2)" +%s)
    serviceelapsedsec=$(( $(date +%s) - servicestartsec))

    # exit if the server started less than 5 minutes ago
    if [ $serviceelapsedsec -lt ${toString minimum-server-lifetime} ]
    then
      echo "server is too young to be stopped"
      exit 1
    fi

    PLAYERS=`printf "list\n" | ${pkgs.rcon.out}/bin/rcon -m -H 127.0.0.1 -p 25575 -P ${rcon-password}`
    if echo "$PLAYERS" | grep "are 0 of a"
    then
      exit 0
    else
      exit 1
    fi
  '';

in
{

  # use NixOS module to declare your Minecraft
  # rcon is mandatory for no-player-connected
  services.minecraft-server = {
    enable = true;
    eula = true;
    openFirewall = false;
    declarative = true;
    serverProperties = {
      server-port = minecraft-port;
      difficulty = 3;
      gamemode = "survival";
      force-gamemode = true;
      max-players = 10;
      level-seed = 238902389203;
      motd = "NixOS Minecraft server!";
      white-list = false;
      enable-rcon = true;
      "rcon.password" = rcon-password;
    };
  };

  # don't start Minecraft on startup
  systemd.services.minecraft-server = {
      wantedBy = pkgs.lib.mkForce [];
  };

  # this waits for incoming connection on public-port
  # and triggers listen-minecraft.service upon connection
  systemd.sockets.listen-minecraft = {
    enable = true;
    wantedBy = [ "sockets.target" ];
    requires = [ "network.target" ];
    listenStreams = [ "${toString public-port}" ];
  };

  # this is triggered by a connection on TCP port public-port
  # start hook-minecraft if not running yet and wait for it to return
  # then, proxify the TCP connection to the real Minecraft port on localhost
  systemd.services.listen-minecraft = {
    path = with pkgs; [ systemd ];
    enable = true;
    requires = [ "hook-minecraft.service" "listen-minecraft.socket" ];
    after =    [ "hook-minecraft.service" "listen-minecraft.socket"];
    serviceConfig.ExecStart = "${pkgs.systemd.out}/lib/systemd/systemd-socket-proxyd 127.0.0.1:${toString minecraft-port}";
  };

  # this starts Minecraft is required
  # and wait for it to be available over TCP
  # to unlock listen-minecraft.service proxy
  systemd.services.hook-minecraft = {
    path = with pkgs; [ systemd libressl busybox ];
    enable = true;
    serviceConfig = {
        ExecStartPost = "${wait-tcp.out}/bin/wait-tcp";
        ExecStart     = "${start-mc.out}/bin/start-mc";
    };
  };

  # create a timer running every frequency-check-players
  # that runs stop-minecraft.service script on a regular
  # basis to check if the server needs to be stopped
  systemd.timers.stop-minecraft = {
    enable = true;
    timerConfig = {
      OnCalendar = "${frequency-check-players}";
      Unit = "stop-minecraft.service";
    };
    wantedBy = [ "timers.target" ];
  };

  # run the script no-player-connected
  # and if it returns true, stop the minecraft-server
  # but also the timer and the hook-minecraft service
  # to prepare a working state ready to resume the
  # server again
  systemd.services.stop-minecraft = {
    enable = true;
    serviceConfig.Type = "oneshot";
    script = ''
      if ${no-player-connected}/bin/no-player-connected
      then
        echo "stopping server"
        systemctl stop minecraft-server.service
        systemctl stop hook-minecraft.service
        systemctl stop stop-minecraft.timer
      fi
    '';
  };

}

4. Conclusion §

I'm really happy to have figured out this smart way to create an on-demand Minecraft, and the design can be reused with many other kinds of daemons.

How to hack on Nix and try your changes

Written by Solène, on 19 August 2022.
Tags: #nix #development #nixos

Comments on Fediverse/Mastodon

1. Introduction §

Not obvious development process is hard to document. I wanted to make changes to the nix program, but I didn't know how to try them.

Fortunately, a coworker explained to me the process, and here it is!

The nix project GitHub page

2. Get the sources and compile §

First, you need to get the sources of the project, and compile it in some way to run it from the project directory:

git clone https://github.com/NixOS/nix/
cd nix
nix-shell
./bootstrap.sh
./configure --prefix=$PWD
make

3. Run the nix daemon §

In order to try nix, we need to stop nix-daemon.service, but also stop nix-daemon.socket to prevent it to restart the nix-daemon.

systemctl stop nix-daemon.socket
systemctl stop nix-daemon.service

Now, when you want your nix-daemon to work, just run this command from the project directory:

sudo bin/nix --extra-experimental-features nix-command daemon

Note this command doesn't fork on background.

If you need some settings in the nix.conf file, you have to create etc/nix/nix.conf relative to the project directory.

4. Restart the nix-daemon §

Once you are done with the development, exit your running daemon and restart the service and socket.

systemctl start nix-daemon.socket
systemctl start nix-daemon.service

Why is the OpenBSD documentation so good?

Written by Solène, on 18 August 2022.
Tags: #openbsd #documentation

Comments on Fediverse/Mastodon

1. Introduction §

The OpenBSD operating system is known to be secure, but also for having an accurate and excellent documentation. In this text, I'll try to figure out what makes the OpenBSD documentation so great.

The OpenBSD project website

2. A multi medias documentation §

Here is a list of supports used to distribute information:

  • first email upon installation
  • man pages
  • website
  • Frequently Asked Questions on the website
  • Examples
  • Commit history
  • Newsletters for announcement

Let's study them one by one.

2.1. The first email §

After you installed OpenBSD, when you log in as root for the first time, you are greeted by a message saying you received an email. In fact, there is an email from Theo De Raadt crafted at install time which welcomes you to OpenBSD. It gives you a few hints about how to get started, but most notably it leads you to the afterboot(8) man page.

The afterboot(8) man page is described as "things to check after the first complete boot", it will introduce you to the most common changes you may want to do on your system. But most importantly, it explains how to use the man page like looking at the SEE ALSO section leading to other man pages related to the current one.

The afterboot(8) man page

2.2. Man pages §

The man pages are a way to ship documentation with a software, usually you find a man page with the same name as the command or configuration file you want to document. It seems man pages appeared in 1971, the "man" stands for manual.

Wikipedia page about the man page

The manual pages are literally the core of the OpenBSD documentation, they follow some standard and contains much metadata in it. When you write a man page, you not only write text, but you describe your text. For instance, when we need to refer to another man page, we will use the tag "cross-reference", this rich format allows accurate rendering but also accurate searches.

When we refer at a page in a text discussion, we often write their name including the section, like man(1). If you see man(1), you understand it's a man page for "man" within the first section. There are 9 sections of man pages, this is an old way to sort them into categories, so if two things have the same name, you use the section to distinguishes them. Here is an example, "man passwd" will display passwd(1), which is a program to change the password of a user, however you could want to read passwd(5) which describes the format of the file /etc/passwd, in this case you would use "man 5 passwd". I always found this way of referring to man pages very practical.

On OpenBSD, there are man pages for all the base systems programs, and all the configuration files. We always try to be very consistent in the way information is shown, and the wording is carefully chosen to be as clear as possible. They are a common effort involving multiple reviewers, changes must be approved by at least one member of the team. When an OpenBSD program is modified, the man page must be updated accordingly. The pages are also occasionally updated to include more history explaining the origins of the commands, it's always very instructive.

When it comes to packages, there is no guarantee as we just bundle upstream software, they may not provide a man page. However, packages maintainers offers a "pkg-readme" file for packages requiring very specific tuning, theses files can be found in /usr/local/share/doc/pkg-readmes/.

Online OpenBSD man pages reader: the rich format shines here

2.3. Website §

One way to distribute information related to OpenBSD is the website, it explains what the project is about, on which hardware you can install it, why it exists and what it provides. It has a lot of information which are interesting before you install OpenBSD, so they can't be in a man pages.

The OpenBSD website

2.4. FAQ §

I chose the treat the Frequently Asked Questions part of the website as a different support for documentation. It's a special place that contains real world use cases, while the man pages are the reference for programs or configuration, they lack the big picture overview like "how to achieve XY on OpenBSD". The FAQ is particularly well crafted, it has different categories such as multimedia, virtualization and VPNs...

The OpenBSD FAQ

2.5. Examples §

The OpenBSD installation comes with a directory /etc/examples/ providing configuration file samples and comments. They are a good way to get started with a configuration file and understand the file format described in the according man page.

2.6. Commits history §

This part is not for end users, but for contributors. When a change is done in the sources, there is often a great commit message explaining the logic of the code and the reasons for the changes. I say often because some trivial changes doesn't require such explanations every time. The commit messages are a valuable source of information when you need to know more about a component.

2.7. Announcements by email §

Documentation is also keeping the users informed about important news. OpenBSD is using an opt-in method with the mailing lists. One list that is important for information is announce@openbsd.org, news releases and erratas are published here. This is a simple and reliable method working for everyone having an email.

2.8. No wiki §

This is an important point in my opinion, all the OpenBSD documentation is stored in the sources trees, they must be committed by someone with a commit access. Wiki often have orphan pages, outdated information, duplicates pages with contrary content. While they can be rich and useful, their content often tend to rot if the community doesn't spend a huge time to maintain them.

2.9. One system as a whole §

Finally, most of the above is possible because OpenBSD is developed by the same team. The team can enforce their documentation requirements from top to bottom, which lead to accurate and consistent documentation all across the system. This is more complicated on a Linux system where all components come from various teams with different methods.

When you get your hands on OpenBSD, you should be able to understand how to use all the components from the base system (= not the packages) with just the man pages, being offline doesn't prevent you to configure your system.

3. Conclusion §

What makes a good documentation? It's hard to tell. In my opinion, having a trustful source of knowledge is the most important, whatever the format or support. If you can't trust what you read because it may be outdated, or not applying on your current version, it's hard to rely on it. Man pages are a good format, very practical, but only when they are well written, but this is a difficult task requiring a lot of time.

BTRFS deduplication using bees

Written by Solène, on 16 August 2022.
Tags: #nixos #btrfs #linux

Comments on Fediverse/Mastodon

1. Introduction §

BTRFS is a Linux file system that uses a Copy On Write (COW) model. It is providing many features like on the fly compression, volumes management, snapshots and clones etc...

Wikipedia page about Copy on write

However, BTRFS doesn't natively support deduplication, which is a feature that looks for chunks in files to see if another file share that block, if so, only one chunk of data can be used for both files. In some scenarios, this can drastically reduce the disk space usage.

This is where we can use "bees", a program that can do offline deduplication for BTRFS file systems. In this context, offline means it's done when you run a command, while it could be live/on the fly where deduplication is instantly applied. HAMMER file system from DragonFly BSD is doing offline deduplication, while ZFS is doing it live. There are pros and cons for both models, ZFS documentation recommends 1 GB of memory per Terabyte of disk when deduplication is enabled, because it requires to have all chunks hashes in memory.

Bees GitHub page project

2. Usage §

Bees is a service you need to install and start on your system, it has some limitations and caveats documented, but it should work for most users.

You can define a BTRFS file system on which you want deduplication and a load target. Bees will work silently when your system is below the load threshold, and will stop when the load exceeds the limit, this is a simple mechanism to prevent bees to eat all your system resources after some freshly modified/created files need to be scanned.

First time you run bees on a file system that is not empty, it may take a while to scan everything, but then it's really quiet except if you do heavy I/O operation like downloading big files, but it's doing a good job at staying behind the scene.

3. Installation on NixOS §

Add this code to /etc/nixos/configuration.nix and run "nixos-rebuild switch" to apply the changes.

services.beesd.filesystems = {
  root = {
    spec = "LABEL=nixos";
    hashTableSizeMB = 256;
    verbosity = "crit";
    extraOptions = [ "--loadavg-target" "2.0" ];
  };
};

The code suppose your root partition is labelled "nixos", you want a hash table of 256 MB (this will be used by bees) and you don't want bees to run when the system load is more than 2.0.

You may want to tune the values, mostly the hash size, depending on your file system size. Bees is for terabytes file systems, but this doesn't mean you can use it for the average user disks.

4. Results §

I tried on my workstation with a lot of build artifacts and git repositories, bees reduced the disk usage from 160 GB to 124 GB, so it's a huge win here.

Later, I tried again on some Steam games with a few proton versions, it didn't save much on the games but saved a lot on the proton installations.

On my local cache server, it did save nothing, but is to be expected.

5. Conclusion §

BTRFS is a solid alternative to ZFS, it requires less memory while providing volumes, snapshots and compression. The only thing it needed for me was deduplication, and I'm glad it's offline, so it doesn't use too much memory.

How to get NixOS hosted at OpenBSD Amsterdam

Written by Solène, on 07 August 2022.
Tags: #nixos #openbsd #hosting

Comments on Fediverse/Mastodon

1. Introduction §

In this guide, I'll explain how to create a NixOS VM in the hosting company OpenBSD Amsterdam which only provides OpenBSD VMs hosted on OpenBSD.

I'd like to thank the team at OpenBSD Amsterdam who offered me a VM for this experiment. While they don't support NixOS officially, they are open to have customers running non-OpenBSD systems on their VMs.

OpenBSD Amsterdam hosting service website

2. The steps from OpenBSD to NixOS §

Here is a short description of the steps required to get NixOS installed on OpenBSD Amsterdam.

  1. Generate a NixOS VM disk file or use the one I provide
  2. Rent a VM at OpenBSD Amsterdam (5€ / month for 1 vCPU, 1GB of memory and 50 GB of hdd, with a dedicated IPv4, working IPv6 and reverse DNS)
  3. Connect to the hypervisor in order to get the serial console access to your VM
  4. Connect with ssh to your VM to reboot it
  5. In the serial console, upon reboot, boot on bsd.rd (the OpenBSD installer ramdisk)
  6. Overwrite the local disk by fetching your NixOS VM disk file through http/ftp and writing it on the disk file
  7. Reboot on NixOS
  8. Configure the network from the serial console, rebuild the system
  9. Enjoy

3. How to proceed §

You need to order a VM at OpenBSD Amsterdam first. You will receive an email with your VM name, its network configuration (IPv4 and IPv6), and explanations to connect to the hypervisor. We will need to connect to the hypervisor to have a serial console access to the virtual machine. A serial console is a text interface to a machine, you get the machine output displayed in your serial console client, and what you type is sent to the machine as if you had a keyboard connected to it.

It can be useful to read the onboarding guide before starting.

OpenBSD Amsterdam onboarding guide

3.1. Get into the OpenBSD installer §

Our first step is to get into the OpenBSD installer, so we can use it to overwrite the disk with our VM.

Connect to the hypervisor, attach to your virtual machine serial console by using the following command, we admit your VM name is "vm40" in the example:

vmctl console vm40

You can leave the console anytime by typing "~~." to get back into your ssh shell. The keys sequence "~." is used to drop ssh or a local serial console, but when you need to leave a serial console from a ssh shell, you need to use "~~.".

You shouldn't see anything because you won't get anything displayed until something is showed in the machine virtual first tty, you can press "enter" and you should see a login prompt. We don't need it, but it confirms the serial console is working.

In parallel, connect to your VM using ssh, find the root password at the end of ~/.ssh/authorized_keys, use "su -" to become root and run "reboot".

You should see the shutdown sequence scrolling in the hypervisor ssh session displaying the serial console, wait for the machine to reboot to spot for the login prompt, in which you will type bsd.rd:

Using drive 0, partition 3.
Loading......
probing: pc0 com0 mem[638K 3838M 4352M a20=on]
disk: hd0+
>> OpenBSD/amd64 BOOT 3.53
com0: 115200 baud
switching console to com0
>> OpenBSD/amd64 BOOT 3.53
boot> bsd.rd [ENTER] # you need to type bsd.rd

3.2. Copy the NixOS VM from the installer §

In this step, we will use the installer to fetch the NixOS VM disk and overwrite the local disk with it.

  • in the installer, type "S" to get a shell:
[...]
Welcome to the OpenBSD/amd64 7.2 installation program.
(I)nstall, (U)pgrade, (A)utoinstall or (S)hell?
  • enable the network using DHCP with the command:
ifconfig vio0 up autoconf
  • create the disk device in /dev because it's missing by default:
cd /dev
sh MAKEDEV sd0
  • fetch the NixOS disk and overwrite the local drive with it:
  • (remove the gunzip part if you didn't compress your VM disk file)
ftp -o - https://perso.pw/nixos/vm.disk.gz | gunzip -f -c | dd of=/dev/rsd0c bs=10M
  • reboot using the command "reboot"

3.3. NixOS grub menu §

At this step, in the serial console you should see a GRUB boot menu, it will boot the first entry after a few seconds. Then NixOS will start booting. In this menu you can access older versions of your system.

After the text stopped scrolling press enter. You should see a login prompt, you can log in with the username "root" and the default password "nixos" if you used my disk image.

3.4. Configuring NixOS §

If you used my template, your VM still doesn't have network connectivity, you need to edit the file /etc/nixos/configuration.nix in which I've put the most important variables you want to customize at the top of the file. You need to configure your IPv4 and IPv6 addresses and their gateways, and also your username with an ssh key to connect to it, and the system name.

Once you are done, run "nixos-rebuild switch", you should have network if you configured it correctly.

After the rebuild, run "passwd your_user" if you want to assign a password to your newly declared user.

You should be able to connect to your VM using its public IP and your ssh key with your username.

EXTRA: You may want to remove the profile minimal.nix which is imported: it disables documentation and the use of X libraries, but this may trigger packages compilation as they are not always built without X support.

3.5. Resizing the partition (last step) §

Because we started with a small 2 GB raw disk to create the virtual machine, the partition still has 2 GB only. We will have to resize the partition /dev/vda1 to take all the disk space, and then resize the ext4 file system.

First step is to extend the partition to 50 GB, the size of the virtual disk offered at openbsd.amsterdam.

# nix-shell -p parted
# parted /dev/vda
(parted) resizepart 1
Warning: The partition /dev/vda1 is currently in use. Are you sure to continue?
Yes/No? yes
End? [2147MB]? 50GB
(parted) quit

Second step is to resize the file system to fill up the partition:

# resize2fs /dev/vda1
The file system /dev/vda1 is mounted on / ; Resizing done on the fly
old_desc_blocks = 1, new_desc_blocks = 6
The file system /dev/vda1 now has a size of 12206775 blocks (4k).

Done! "df -h /" should report the new size.

3.6. Congratulations §

You have a fully functional NixOS VM!

4. Creating the VM §

While I provide a bootable NixOS disk image at https://perso.pw/nixos/vm.disk.gz , you can generate yours with this guide.

  • create a raw disk of 2 GB to install the VM in it
qemu-img create -f raw vm.disk 2G
  • run qemu in a serial console to ensure it works, in the grub boot menu you will need to select the 4th choice enabling serial console in the installer. In this no graphics qemu mode, you can stop qemu by pressing "ctrl+a" and then "c" to drop into qemu's own console, and type "quit" to stop the process.
qemu-system-x86_64 \
  -smp 2 -m 4G \
  -enable-kvm \
  -display curses -nographic \
  -cdrom nixos-minimal*.iso \
  -drive file=vm.disk,if=virtio,format=raw
  • we create the partitions and prepare the chroot
sudo -i
parted /dev/vda -- mklabel msdos
parted /dev/vda -- mkpart primary 1MiB 100%
mkfs.ext4 -L nixos /dev/vda1
mount /dev/disk/by-label/nixos /mnt
mkdir -p /mnt/etc/nixos/
  • edit the file /mnt/etc/nixos/configuration.nix , the NixOS install has nano available by default, but you can have your favorite editor by using "nix-shell -p vim" if you prefer vim. Here is a configuration file that will work:

NixOS configuration.nix file for OpenBSD Amsterdam

  • edit the file /mnt/etc/nixos/hardware-configuration.nix

NixOS hardware-configuration.nix file for OpenBSD Amsterdam

  • we can run the installer, it will ask for the root password, and then we can shut down the VM
nixos-install
systemctl poweroff

Now, you have to host the disk file somewhere to make it available through http or ftp protocol in order to retrieve it from the openbsd.amsterdam VM. I'd recommend compressing the file by running gzip on it, that will drastically reduce its size from 2GB to ~500MB.

5. Full disk encryption §

The ext4 file system offers a way to encrypt specific directories, it can be enough for most users.

However, if you want to enable full disk encryption, you need to use the guide above to generate your VM, but you need to create a separate /boot partition and create a LUKS volume for the root partition. This is explained in the NixOS manual, in the installer section. You should adapt the according bits in the configuration file to match your new setup.

Don't forget you will need to connect to the hypervisor to type your password through the serial access every time you will reboot.

6. Known issue and workaround §

There is an issue with the OpenBSD hypervisor and Linux kernels at the moment, when you reboot your Linux VM, the VM process on the OpenBSD host crashes. Fortunately, it crashes after all the shutdown process is done, so it doesn't let the file system in a weird state.

This problem is fixed in OpenBSD -current as of August 2022, and won't happen in OpenBSD 7.2 hypervisors that will be available by the end of the year.

A simple workaround is to open a tmux session in the hypervisor to run an infinite loop regularly checking if your VM is running, and starting it when it's stopped:

while true ; do vmctl status vm40 | grep stopped && vmctl start vm40 ; sleep 30 ; done

Mailing list archives: vmx_fault_page: uvm_fault returns 14, GPA=0xfe001818, rip=0xffffffffc0d6bb96

Mailing list archives: vmm page fault with VM upgraded from Ubuntu 18LTS to 20LTS

7. Conclusion §

It's great to have more choice when you need a VM. The OpenBSD Amsterdam team is very kind, professional and regularly give money to the OpenBSD project.

8. Going further §

This method should work for other hosting providers, given you can access the VM disk from an live environment (installer, rescue system etc..). You may need to pay attention to the disk device, and if you can't obtain a serial console access to your system, you need to get the network done right in the VM before copying it to the disk.

In the same vein, you can use this method to install any operating system supported by the hypervisor. I chose NixOS because I love this system, and it's easy to reproduce a result with its declarative paradigm.

Solving a bad ARP behavior on a Linux router

Written by Solène, on 05 August 2022.
Tags: #linux #networking

Comments on Fediverse/Mastodon

1. Introduction §

So, I recently switched my home router to Linux but had a network issues for devices that would get/renew their IP with DHCP. They were obtaining an IP, but they couldn't reach the router before a while (between 5 seconds to a few minutes), which was very annoying and unreliable.

After spending some time with tcpdump on multiple devices, I found the issue, it was related to ARP (the protocol to discover MAC addresses associate them with IPs).

Wikipedia page about the ARP protocol

The arp flux problem explained

2. My setup §

I have an unusual network setup at home as I use my ISP router for Wi-Fi, switch and as a modem, the issue here is that there are two subnets on its switch.


      +------------------+                                +-----------------+
      | ISP MODEM        | ethernet #1         ethernet #1|                 |
      |                  |<------------------------------>|                 |
      |                  | 192.168.1.254     192.168.1.111|                 |
      |                  |                                |  linux router   |
      |                  |                                |                 |
      |                  | ethernet #2         ethernet #2|                 |
      |                  |<------------------------------>|                 |
      |                  |                    10.42.42.42 |                 |
      |                  |                                |                 |
      |                  |                                |                 |
      +------------------+                                +-----------------+
       ^ethernet #4     ^ ethernet #3
       |                |
       |                |
       |                +----> some switch with many devices
       |
       v 10.42.42.150
       NAS

Because the modem is reachable over 192.168.1.0/24 and is used by the router on that switch, but that the LAN network uses the same switch with 10.42.42.0/24, ARP packets arrives on two network interfaces of the router, for addresses that are non routables (ARP packets for 10.42.42.0 would arrive at the interface 192.168.1.0 or the opposite).

3. Solution §

There is simple solution, but it was very complicated to find as it's not obvious. We can configure the Linux kernel to discard ARP packets that are related to non routable addresses, so the interface with a 192.168.1.0/24 address will discard packets for the 10.42.42.0/24 network and vice-versa.

You need to define the sysctl net.ipv4.conf.all.arp_filter to 1.

sysctl net.ipv4.conf.all.arp_filter=1

This can be set per interface if you have specific need.

Documentation of the sysctl available on Linux

4. Conclusion §

This was a very annoying issue, incredibly hard to troubleshoot. I suppose OpenBSD has this strict behavior by default because I didn't have this problem when the router was running OpenBSD.

Fair Internet bandwidth management on a network using Linux

Written by Solène, on 05 August 2022.
Tags: #linux #bandwidth #qos

Comments on Fediverse/Mastodon

1. Introduction §

A while ago I wrote an OpenBSD guide to fairly share the Internet bandwidth to the LAN network, it was more or less working. Now I switched my router to Linux, I wanted to achieve the same. Unfortunately, it's not really documented as well as on OpenBSD.

The command needed for this job is "tc", acronym for Traffic Control, the Jack of all trades when it comes to manipulate your network traffic. It can add delays or packets lost (this is fun when you want to simulate poor conditions), but also traffic shaping and Quality of Service (QoS).

Wikipedia page about tc

Fortunately, tc is not that complicated for what we will achieve in this how-to (fair share) and will give results way better than what I achieved with OpenBSD!

2. How it works §

I don't want to explain how the whole stack involved works, but with tc we will define a queue on the interface we want to apply the QoS, it will create a number of flows assigned to each active network streams, each active flow will receive 1/total_active_flows shares of bandwidth. It mean if you have three connections downloading data (from the same computer or three different computers), they should in theory receive 1/3 of bandwidth each. In practice, you don't get exactly that, but it's quite close.

3. Setup §

I made a script with variables to make it easy to reuse, it deletes any traffic control set on the interfaces and then creates the configuration. You are supposed to run it at boot.

It contains two variables, DOWNLOAD_LIMIT and UPLOAD_LIMIT that should be approximately 95% of each maximum speed, it can be defined in bits with kbits/mbits or in bytes with kbps/mbps, the reason to use 95% is to let the router some room for organizing the packets. It's like a "15 puzzle", you need one empty square to use it.

#!/bin/sh

TC=$(which tc)

# LAN interface on which you have NAT
LAN_IF=br0

# WAN interface which connects to the Internet
WAN_IF=eth0

# 95% of maximum download
DOWNLOAD_LIMIT=13110kbit

# 95% of maximum upload
UPLOAD_LIMIT=840kbit

$TC qdisc del dev $LAN_IF root
$TC qdisc del dev $WAN_IF root

$TC qdisc add dev $WAN_IF root handle 1: htb default 1
$TC class add dev $WAN_IF parent 1: classid 1:1 htb rate $UPLOAD_LIMIT
$TC qdisc add dev $WAN_IF parent 1:1 fq_codel noecn

$TC qdisc add dev $LAN_IF root handle 1: htb default 1
$TC class add dev $LAN_IF parent 1: classid 1:1 htb rate $DOWNLOAD_LIMIT
$TC qdisc add dev $LAN_IF parent 1:1 fq_codel

4. Conclusion §

tc is very effective but not really straightfoward to understand. What's cool is you can apply it on the fly without incidence.

It has been really effective for me, now if some device is downloading on the network, it doesn't affect much the other devices when they need to reach the Internet.

5. Credits §

After lurking on the Internet looking for documentation about tc, I finally found someone who made a clear explanation about this tool. tc is documented, but it's too abstract for me.

linux home router traffic shaping with fq_codel

Creating a NixOS live USB for a full featured APU router

Written by Solène, on 03 August 2022.
Tags: #networking #security #nixos #apu

Comments on Fediverse/Mastodon

1. Introduction §

At home, I'm running my own router to manage Internet, run DHCP, do filter and caching etc... I'm using an APU2 running OpenBSD, it works great so far, but I was curious to know if I could manage to run NixOS on it without having to deal with serial console and installation.

It turned out it's possible! By configuring and creating a live NixOS USB image, one can plug the USB memory stick into the router and have an immutable NixOS.

NixOS wiki about creating a NixOS live CD/USB

2. Network diagram §

Here is a diagram of my network. It's really simple except the bridge part that require an explanation. The APU router has 3 network interfaces and I only need 2 of them (one for WAN and one for LAN), but my switch doesn't have enough ports for all the devices, just missing one, so I use the extra port of the APU to connect that device to the whole LAN by bridging the two network interfaces.

                +----------------+
                |  INTERNET      |
                +----------------+
                       |
                       |
                       |
                +----------------+
                | ISP ROUTER     |
                +----------------+
                       | 192.168.1.254
                       |
                       |
                       | 192.168.1.111
                +----------------+
                |   APU ROUTER   |
                +----------------+
                |bridge #2 and #3|
                | 10.42.42.42    |
                +----------------+
                  |port #3    |
                  |           | port #2
       +----------+           |
       |                      |
       |                   +--------+     +----------+
       | 10.42.42.150      | switch |-----| Devices  |
  +--------+               +--------+     +----------+
  | NAS    |
  +--------+

3. Feature list §

Here is a list of services I need on my router, this doesn't include all my filtering rules and specific tweaks.

- DHCP server

- DNS resolving caching using unbound

- NAT

- SSH

- UPnP

- Munin

- Bridge ethernets ports #2 and #3 to use #3 as an extra port like a switch

4. The whole configuration §

For the curious, here is the whole configuration of the setup. In the sections after, I'll explain each parts of the code.

{ config, pkgs, ... }:
{

  isoImage.squashfsCompression = "zstd -Xcompression-level 5";

  powerManagement.cpuFreqGovernor = "ondemand";

  boot.kernelPackages = pkgs.linuxPackages_xanmod_latest;
  boot.kernelParams = [ "copytoram" ];
  boot.supportedFilesystems = pkgs.lib.mkForce [ "btrfs" "vfat" "xfs" "ntfs" "cifs" ];

  services.irqbalance.enable = true;

  networking.hostName = "kikimora";
  networking.dhcpcd.enable = false;
  networking.usePredictableInterfaceNames = true;
  networking.firewall.interfaces.eth0.allowedTCPPorts = [ 4949 ];
  networking.firewall.interfaces.br0.allowedTCPPorts = [ 53 ];
  networking.firewall.interfaces.br0.allowedUDPPorts = [ 53 ];

  security.sudo.wheelNeedsPassword = false;

  services.acpid.enable = true;
  services.openssh.enable = true;

  services.unbound = {
    enable = true;
    settings = {
      server = {
        interface = [ "127.0.0.1" "10.42.42.42" ];
        access-control =  [
          "0.0.0.0/0 refuse"
          "127.0.0.0/8 allow"
          "10.42.42.0/24 allow"
        ];
      };
    };
  };

  services.miniupnpd = {
      enable = true;
      externalInterface = "eth0";
      internalIPs = [ "br0" ];
  };

  services.munin-node = {
      enable = true;
      extraConfig = ''
      allow ^63\.12\.23\.38$
      '';
  };

  networking = {
    defaultGateway = { address = "192.168.1.254"; interface = "eth0"; };
    interfaces.eth0 = {
        ipv4.addresses = [
            { address = "192.168.1.111"; prefixLength = 24; }
        ];
    };

    interfaces.br0 = {
        ipv4.addresses = [
            { address = "10.42.42.42"; prefixLength = 24; }
        ];
    };

    bridges.br0 = {
        interfaces = [ "eth1" "eth2" ];
    };

    nat.enable = true;
    nat.externalInterface = "eth0";
    nat.internalInterfaces = [ "br0" ];
  };

  services.dhcpd4 = {
      enable = true;
      extraConfig = ''
      option subnet-mask 255.255.255.0;
      option routers 10.42.42.42;
      option domain-name-servers 10.42.42.42, 9.9.9.9;
      subnet 10.42.42.0 netmask 255.255.255.0 {
          range 10.42.42.100 10.42.42.199;
      }
      '';
      interfaces = [ "br0" ];
  };

  time.timeZone = "Europe/Paris";

  users.mutableUsers = false;
  users.users.solene.initialHashedPassword = "$6$ffffffffffffffff$TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
  users.users.solene = {
    isNormalUser = true;
    extraGroups = [ "sudo" "wheel" ];
  };
}

5. Explanations §

This setup deserves some explanations with regard to each part of it.

5.1. Live USB specific §

I prefer to use zstd instead of xz for compressing the liveUSB image, it's way faster and the compression ratio is nearly identical as xz.

  isoImage.squashfsCompression = "zstd -Xcompression-level 5";

There is currently an issue when trying to use a non default kernel, ZFS support is pulled in and create errors. By redefining the list of supported file systems you can exclude ZFS from the list.

  boot.supportedFilesystems = pkgs.lib.mkForce [ "btrfs" "vfat" "xfs" "ntfs" "cifs" ];

5.2. Kernel and system §

The CPU frequency should stay at the minimum until the router has some load to compute.

  powerManagement.cpuFreqGovernor = "ondemand";
  services.acpid.enable = true;

This makes the system to use the XanMod Linux kernel, it's a set of patches reducing latency and improving performance.

Xanmod XanMod project website

  boot.kernelPackages = pkgs.linuxPackages_xanmod_latest;

In order to reduce usage of the USB memory stick, upon boot all the content of the liveUSB will be loaded in memory, the USB memory stick can be removed because it's not useful anymore.

  boot.kernelParams = [ "copytoram" ];

The service irqbalance is useful as it assigns certain IRQ calls to specific CPUs instead of letting the first CPU core to handle everything. This is supposed to increase performance by hitting CPU cache more often.

  services.irqbalance.enable = true;

5.3. Network interfaces §

As my APU wasn't running Linux, I couldn't know the name if the interfaces without booting some Linux on it, attach to the serial console and check their names. By using this setting, Ethernet interfaces are named "eth0", "eth1" and "eth2".

  networking.usePredictableInterfaceNames = true;

Now, the most important part of the router setup, doing all the following operations:

- assign an IP for eth0 and a default gateway

- create a bridge br0 with eth1 and eth2 and assign an IP to br0

- enable NAT for br0 interface to reach the Internet through eth0

  networking = {
    defaultGateway = { address = "192.168.1.254"; interface = "eth0"; };
    interfaces.eth0 = {
        ipv4.addresses = [
            { address = "192.168.1.111"; prefixLength = 24; }
        ];
    };

    interfaces.br0 = {
        ipv4.addresses = [
            { address = "10.42.42.42"; prefixLength = 24; }
        ];
    };

    bridges.br0 = {
        interfaces = [ "eth1" "eth2" ];
    };

    nat.enable = true;
    nat.externalInterface = "eth0";
    nat.internalInterfaces = [ "br0" ];
  };

This creates a user solene with a predefined password, add it to the wheel and sudo groups in order to use sudo. Another setting allows wheel members to run sudo without password, this is useful for testing purpose but should be avoided on production systems. You could add your SSH public key to ease and secure SSH access.

  users.mutableUsers = false;
  security.sudo.wheelNeedsPassword = false;
  users.users.solene.initialHashedPassword = "$6$bVPyGA3aTEMTIGaX$FYkFnOqwk8GNfeLEfppgGjZ867XxirQ19v1337.GSRdzxw7JrRi6IcpaEdeSuNTHSxIIhunter2Iy6clqB14b0";
  users.users.solene = {
    isNormalUser = true;
    extraGroups = [ "sudo" "wheel" ];
  };

5.4. Networking services §

This will run a DHCP server advertising the local DNS server and the default gateway, as it defines ranges for DHCP clients in our local network.

  services.dhcpd4 = {
      enable = true;
      extraConfig = ''
      option subnet-mask 255.255.255.0;
      option routers 10.42.42.42;
      option domain-name-servers 10.42.42.42, 9.9.9.9;
      subnet 10.42.42.0 netmask 255.255.255.0 {
          range 10.42.42.100 10.42.42.199;
      }
      '';
      interfaces = [ "br0" ];
  };

All systems require a name in order to work, and we don't want to use DHCP to get the IPs addresses. We also have to define a time zone.

  networking.hostName = "kikimora";
  networking.dhcpcd.enable = false;
  time.timeZone = "Europe/Paris";

This enables OpenSSH daemon listening on port 22.

  services.openssh.enable = true;

This enables the service unbound, a DNS resolver that is able to do some caching as well. We need to allow our network 10.42.42.0/24 and listen on the LAN facing interface to make it work, and not forget to open the ports TCP/53 and UDP/53 in the firewall. This caching is very effective on a LAN server.

  services.unbound = {
    enable = true;
    settings = {
      server = {
        interface = [ "127.0.0.1" "10.42.42.42" ];
        access-control =  [
          "0.0.0.0/0 refuse"
          "127.0.0.0/8 allow"
          "10.42.42.0/24 allow"
        ];
      };
    };
  };
  networking.firewall.interfaces.br0.allowedTCPPorts = [ 53 ];
  networking.firewall.interfaces.br0.allowedUDPPorts = [ 53 ];

This enables the service miniupnpd, this can be quite dangerous because its purpose is to allow computer on the network to create NAT forwarding rules on demand. Unfortunately, this is required to play some video games and I don't really enjoy creating all the rules for all the video games requiring it.

  services.miniupnpd = {
      enable = true;
      externalInterface = "eth0";
      internalIPs = [ "br0" ];
  };

This enables the service munin-node and allow a remote server to connect to it. This service is used to gather metrics of various data and make graphs from them. I like it because the agent running on the systems is very simple and easy to extend with plugins, and on the server side, it doesn't need a lot of resources. As munin-node listens on the port TCP/4949 we need to open it.

  services.munin-node = {
      enable = true;
      extraConfig = ''
      allow ^13\.17\.23\.28$
      '';
  };
  networking.firewall.interfaces.eth0.allowedTCPPorts = [ 4949 ];

6. Conclusion §

By building a NixOS live image using Nix, I can easily try a new configuration without modifying my router storage, but I could also use it to ssh into the live system to install NixOS without having to deal with the serial console.

How to use sshfs on OpenBSD

Written by Solène, on 23 July 2022.
Tags: #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

Today we will learn about how to use sshfs, a program to mount a remote directory through ssh into our local file system.

But OpenBSD has a different security model than in other Unixes systems, you can't use FUSE (Filesystem in USErspace) file systems from a non-root user. And because you need to run your fuse mount program as root, the mount point won't be reachable by other users because of permissions.

Fortunately, with the correct combination of flags, this is actually achievable.

sshfs project website

2. Setup §

First, as root we need to install sshfs-fuse from packages.

# pkg_add sshfs-fuse

3. Permissions errors when mounting with sshfs §

If we run sshfs as our user, we will get the error "fuse_mount: permission denied", so root is mandatory for running the command.

But if we run "sshfs server.local:/home /mnt" as root, we can't reach the /mnt directory with our regular user because it's root property:

$ ls /mnt/
ls: /mnt/: Permission denied

This confirms sshfs needs some extra flags to be used for non-root users on OpenBSD.

4. The solution §

As root, we will run sshfs to mount a directory from t470-wifi.local (my laptop Wi-Fi IP address on my LAN) to make it available to our user with uid 1000 and gid 1000 (this is the ids for the first user added), you can find the information about your users with the command "id". We will also use the allow_other mount option.

# sshfs -o idmap=user,allow_other,uid=1000,gid=1000 solene@t470-wifi.local:/home/solene/ /mnt

After this command, when I switch to my user whose id and gid is 1000, I can read and write into /mnt.

5. Credits §

This article exists because many OpenBSD users struggle using sshfs, and it's not easy to find the solution on the Internet.

OpenBSD as NAS FOSDEM talk giving an example of sshfs use

= > https://marc.info/?l=openbsd-misc&m=153390693400573&w=2 misc@openbsd.org email thread explaining why fuse mount behavior changed in 2018

Make nix flakes commands using the same nixpkgs as NixOS does

Written by Solène, on 20 July 2022.
Tags: #nixos #linux #nix

Comments on Fediverse/Mastodon

1. Introduction §

This article will explain how to make the flakes enabled nix commands reusing the nixpkgs repository used as input to build your NixOS system. This will regularly save you time and bandwidth.

2. Flakes and registries §

By default, nix commands using flakes such as nix shell or nix run are pulling a tarball of the development version of nixpkgs. This is the default value set in the nix registry for nixpkgs.

$ nix registry list | grep nixpkgs
global flake:nixpkgs github:NixOS/nixpkgs/nixpkgs-unstable

Because of this, when you run a command, you are likely to download a tarball of the nixpkgs repository including the latest commit every time you use flakes, this is particularly annoying because the tarball is currently around 30 MB. There is a simple way to automatically set your registry to define the nixpkgs repository to the local archive used by your NixOS configuration.

To your flake.nix file describing your system configuration, you should have something similar to this:

inputs.nixpkgs.url = "nixpkgs/nixos-unstable";

[...]
nixosConfiguration = {
  my-computer =lib.nixosSystem {
    specialArgs = { inherit inputs; };
    [...]
  };
};

Edit /etc/nixos/configuration.nix and make sure you have "inputs" listed in the first line, such as:

{ lib, config, pkgs, inputs, ... }:

And add the following line to the file, and then rebuild your system.

nix.registry.nixpkgs.flake = inputs.nixpkgs;

After this change, running a command such as "nix shell nixpkgs#gnumake" will reuse the same nixpkgs from your nix store used by NixOS, otherwise it would have been fetching the latest archive from GitHub.

3. nix-shell vs nix shell §

If you started using flakes, you may wonder why there are commands named "nix-shell" and "nix shell", they work totally differently.

nix-shell and non flakes commands use the nixpkgs offered in the NIX_PATH environment variable, which should be set to a directory managed by nix-channel, but the channels are obsoleted by flakes...

Fortunately, in the same way we synchronized the system flakes with the commands flakes, you can add this code to use the system nixpkgs with your nix-shell:

nix.nixPath = [ "nixpkgs=/etc/channels/nixpkgs" "nixos-config=/etc/nixos/configuration.nix" "/nix/var/nix/profiles/per-user/root/channels" ];
environment.etc."channels/nixpkgs".source = inputs.nixpkgs.outPath;

This requires your user to logout from your current session to be effective. You can then check nix-shell and nix shell use the same nixpkgs source with this snippet. This asks the full path of the test program named "hello" and compares both results, they should match if they use the same nixpkgs.

[ "$(nix-shell -p hello --run "which hello")" = "$(nix shell nixpkgs#hello -c which hello)" ] && echo success

4. Conclusion §

Flakes are awesome, and are in the way of becoming the future of Nix. I hope this article shed some light about nix commands, and saved you some bandwidth.

5. Credits §

I found this information on a blog post of the company Tweag (which is my current employer) in a series of articles about Nix flakes. That's a bit sad I didn't find this information in the official NixOS documentation, but as flakes are still experimental, they are not really covered.

Tweag blog: Nix Flakes, Part 3: Managing NixOS systems

As I found this information on their blog post, and I'm fine giving credits to people, so I have to link their blog post license here.

Creative Commons Attribution 4.0 International license

How to account systemd services bandwidth usage on NixOS

Written by Solène, on 20 July 2022.
Tags: #nixos #bandwidth #monitoring

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1. Introduction §

Did you ever wonder how many bytes a system service is daily receiving from the network? Thanks to systemd, we can easily account this.

This guide targets NixOS, but the idea could be applied on any Linux system using systemd.

NixOS project website

In this article, we will focus on the nix-daemon service.

2. Setup §

We will enable the attribute IPAccounting on the systemd service nix-daemon, this will make systemd to account bytes and packets that received and sent by the service. However, when the service is stopped, the counters are reset to zero and the information logged into the systemd journal.

In order to efficiently gather the network information over time into a database, we will run a script just before the service stops using the preStop service hook.

The script checks the existence of a sqlite database /var/lib/service-accounting/nix-daemon.sqlite, creates it if required, and then inserts the received bytes information of the nix-daemon service about to stop. The script uses the service attribute InvocationID and the current day to ensure that a tuple won't be recorded more than once, because if we restart the service multiple times a day, we need to distinguish all the nix-daemon instances.

Here is the code snippet to add to your /etc/nixos/configuration.nix file before running nixos-rebuild test to apply the changes.

  systemd.services.nix-daemon = {
      serviceConfig.IPAccounting = "true";
      path = with pkgs; [ sqlite busybox systemd ];
      preStop = ''
#!/bin/sh

SERVICE="nix-daemon"
DEST="/var/lib/service-accounting"
DATABASE="$DEST/$SERVICE.sqlite"

mkdir -p "$DEST"

# check if database exists
if ! dd if="$DATABASE" count=15 bs=1 2>/dev/null | grep -Ea "^SQLite format.[0-9]$" >/dev/null
then
cat <<EOF | sqlite3 "$DATABASE"
CREATE TABLE IF NOT EXISTS accounting (
        id TEXT PRIMARY KEY,
        bytes INTEGER NOT NULL,
        day DATE NOT NULL
);
EOF
fi

BYTES="$(systemctl show "$SERVICE.service" -P IPIngressBytes | grep -oE "^[0-9]+$")"
INSTANCE="'$(systemctl show "$SERVICE.service" -P InvocationID | grep -oE "^[a-f0-9]{32}$")'"

cat <<EOF | sqlite3 "$DATABASE"
INSERT OR REPLACE INTO accounting (id, bytes, day) VALUES ($INSTANCE, $BYTES, date('now'));
EOF
     '';
  };

If you want to apply this to another service, the script has a single variable SERVICE that has to be updated.

3. Display the information from the database §

You can use the following command to display the bandwidth usage of the nix-daemon service with a day-by-date report:

$ echo "SELECT day, sum(bytes)/1024/1024 AS Megabytes FROM accounting group by day" | sqlite3 -header -column /var/lib/service-accounting/nix-daemon.sqlite
day         Megabytes
----------  ---------
2022-07-17  173
2022-07-19  3018
2022-07-20  84

Please note this command requires the sqlite package to be installed in your environment.

4. Enhancement §

I have some ideas to improve the setup:

  • The script could be improved to support multiple services within the database by using a new field
  • The command to display data could be improved and turned into a system package to make it easier to use
  • Provide an SQL query for monthly summary

5. Conclusion §

Systemd services are very flexible and powerful thanks to the hooks provided to run script at the right time. While I was interested into network usage accounting, it's also possible to achieve a similar result with CPU usage and I/O accesses.

The Old Computer Challenge V2: done!

Written by Solène, on 19 July 2022.
Tags: #life #offline #oldcomputerchallenge #nocloud

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1. Introduction §

The Old Computer Challenge V2 is over! What a week! It was even more than a week, as it was from 10th to 17th july included, that was 8 days.

2. What I've learned §

To be honest, this challenge was hard and less fun than the previous one as we couldn't communicate about our experiences. It was so hard to schedule my Internet needs over the days than I tried to not use it at all, leaving some time when I had some unexpected need to check something.

Nevertheless, it was still a good experience to go through, it helped me realize many daily small things required Internet without me paying attention anymore. Fortunately, I avoid most streaming services and my multimedia content is all local.

I spend a lot of time every day in instant messaging software, even if they work asynchronously, it often happen to have someone answering within seconds and then we start to chat and time passes. This was a huge time consumer of the daily limited Internet time available in the challenge.

We have a few other people who made the challenge, reading their reports was very interesting and fun.

3. Toward the next challenge §

Now this second challenge is over, our community is still strong and regained some activity. People are already thinking about the next edition and we need to find what do to next. An currently popular idea would be to reduce the Internet speed to RTC (~5 kB/s) instead of limiting time, but we still have some time to debate about the next rules.

We waited one year between the first and second challenge, but this doesn't mean we can't do this more often!

To conclude this article and challenge, I would like to give special thanks to all the people who got involved or interested into the challenge.

How to use Docker from a Linux host system to escalate to root

Written by Solène, on 19 July 2022.
Tags: #security #linux #docker

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1. Introduction §

It's often said Docker is not very good with regard to security, let me illustrate a simple way to get root access to your Linux system through a docker container. This may be useful for people who would have docker available to their user, but whose company doesn't give them root access.

This is not a Docker vulnerability being exploited, just plain Docker by design. It is not a way to become root from *within* the container, you need to be able to run docker on the host system.

If you use this to break against your employer internal rules, this is your problem, not mine. I do write this to raise awareness about why Docker for systems users could be dangerous.

UPDATE: It is possible to run the Docker as a regular user since October 2021.

Run the docker daemon as a user

2. How to proceed §

We will start a simple Alpine docker container, and map the system root file system / on the /mnt container directory.

docker run -v /:/mnt -ti alpine:latest

From there, you can use the command chroot /mnt to obtain a root shell of your system.

You are now free to use "passwd" to change root password, or visudo to edit sudo rules, or you could use the system package manager to install extra software you want.

3. Some analogy §

If you don't understand why this works, here is a funny analogy. Think about being in a room as a human being, but you have a super power that allows you to imagine some environment in a box in front of you.

Now, that box (docker) has a specific feature: it permits you to take a piece of your current environment (the filesystem) to project it in the box itself. This can be useful if you want to imagine a beach environment and still have your desk in it.

Now, project your whole room (the host filesystem) into your box, and now, you are all mighty for what's happening in the box, which turn to be your own room (you are root, the super user).

4. Conclusion §

Users who have access to docker can escalate to root in a few seconds and megabytes.

Storing information on paper using the Pen To Paper protocol

Written by Solène, on 15 July 2022.
Tags: #life #fun #nocloud

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1. Introduction §

Here is a draft for a protocol named PTPDT, an acronym standing for Pen To Paper Data Transfer. It comes with its companion specification Paper To Brain.

The protocol describes how a pen can be used to write data on a sheet of paper. Maybe it would be better named as Brain To Paper Protocol.

2. Terminology §

Some words refer to specific concepts:

  • pen: a pen or pencil
  • paper: material on which pen can be used
  • writer: the author when using the pen
  • reader: the author when reading the paper
  • anoreader: anonymous reader reading the paper

3. Model §

The writer uses a pen on a paper in order to duplicate information from his memories into the paper.

We won't go into technical implementation details about how the pen does transmit information into the paper, we will admit some ink or equivalent is used in the process without altering data.

4. Nomenclature §

When storing data with this protocol, paper should be incrementally numbered for ordered information that wouldn't fit on a single storage paper unit. The reader could then read the papers in the correct order by following the numbering.

It is advised to add markers before and after the data to delimit its boundaries. Such mechanism can increase reliability of extracting data from paper, or help to recover from mixed up papers.

5. Encoding §

It is recommended to use a single encoding, often known as language, for a single piece of paper. Abstract art is considered a blob, and hence doesn't have any encoding.

6. Extracting data §

There are three ways to extract data from paper:

  1. lossless: all the information is extracted and can be used and replicated by the reader
  2. lossy: all the information is extracted and could be used by the reader
  3. partial: some pieces of information are extracted with no guarantee it can be replicated or used

In order to retrieve data from paper, reader and anoreader must use their eyesight to pass the paper data to their brain which will decode the information and store it internally. If reader's brain doesn't know the encoding, the data could be lossy or partially extracted.

It's often required to make multiple read passes to achieve a lossless extraction.

7. Compression §

There are different compression algorithms to increase the pen output bandwidth, the reader and anoreader must be aware of the compression algorithm used.

8. Encryption §

The protocol doesn't enforce encryption. The writer can encrypt data on paper so anoreader won't be able to read this, however this will increase the mental charge for both the writer and the reader.

9. Accessibility §

This protocol requires the writer to be able to use a pen.

This protocol requires the reader and anoreader to be able to see. We need to publish Braille To Paper Data Transfer for an accessible alternative.

The Old Computer Challenge V2: day 5

Written by Solène, on 14 July 2022.
Tags: #life #offline #oldcomputerchallenge #nocloud

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Some quick news for the Old Computer Challenge!

As it's too tedious to monitor the time spent on the Internet, I'm now using a chronometer for the day... and stopped using Internet in small bursts. It's also currently super hot where I live right now, so I don't want to do much stuff with the computer...

I can handle most of my computer needs offline. When I use Internet, it's now for a solid 15 minutes, except when I connect from my phone for checking something quickly without starting my computer, I rarely need to connect it more than a minute.

This is a very different challenge than the previous one because we can't stay online on IRC all day speaking about tricks to improve our experience with the current challenge. On the other hand, it's the opportunity to show our writing skills to tell about what we are going through.

I didn't write the last days because there wasn't much to say. I miss internet 24/7 though, and I'll be happy to get back on the computer without having to track my time and stop after the hour, which always happen too soon!

The Old Computer Challenge V2: day 2

Written by Solène, on 11 July 2022.
Tags: #life #offline #oldcomputerchallenge #nocloud

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1. Intro §

Day 2 of the Old Computer Challenge, 60 minutes of Internet per day. Yesterday I said it was easy. I changed my mind.

2. Internet feels natural §

I think my parents switched their Internet subscription from RTC to DSL around 2005, 17 years ago, it was a revolution for us because not only it was multiple time faster (up to 16 kB/s !) but it was unlimited in time! Since then, I only had unlimited Internet (no time, no quota), and it became natural to me to expect to have Internet all the time.

Because of this, it's really hard for me to just think about tracking my Internet time. There are many devices in my home connected to the Internet and I just don't think about it when I use them, I noticed I was checking emails or XMPP on my phone, I turned its Wi-Fi on in the morning and forgot about it then.

There are high chances I used more than my quota yesterday because of my phone, but I also forgot to stop the time accounting script. (It had a bug preventing it to stop correctly for my defense). And then I noticed I was totally out of time yesterday evening, I had to plan a trip for today which involved looking at some addresses and maps, despite I have a local OpenStreetMap database it's rarely enough to prepare a trip when you go somewhere the first time, and that you know you will be short on time to figure things out on the spot.

3. Internet everywhere §

Ah yes, my car also has an Internet connection with its own LTE access, I can't count it as part as the challenge because it's not really useful (I don't think I used it at all), but it's there.

And it's in my Nintendo Switch too, but it has an airplane mode to disable connectivity.

And Steam (the game library) requires being online when streaming video games locally (to play on the couch)...

So, there are many devices and software silently (not always) relying on the Internet to work that we don't always know exactly why they need it.

4. Open source work §

While I said I wasn't really restrained with only one hour of Internet, this was yesterday. I didn't have a feeling to work on open source project in the day, but today I would like to help to review packages updates/changes, but I couldn't. Packaging requires a lot of bandwidth and time, it requires searching for errors if they are known or new, it just can't be done offline because it relies on many external packages that has to be downloaded, and with a DSL line it takes a lot of time to keep a system up to date with its development branch.

Of course, with some base materials like the project main repository, it's possible to contribute, but not really at reviewing packages.

5. Second day review §

I will add my counter a 30 minutes penalty for not tracking my phone Internet usage today. I still have 750 seconds of Internet when writing this blog post (including the penalty).

Yesterday I improved my blog deployment to reduce the time taken by the file synchronization process, from 18s to 4s. I'm using rsync, but I have four remote servers to synchronize: 1 for http, 1 for gemini, 1 for gopher and 1 for a gopher backup. As the output files of my blog are always generated and brand new, rsync was recopying all the files to update the modification time, now I'm using -c for checksum and -I to ignore times, and it's significantly faster and ensure the changes are copied. I insist about the changes being copied, because if you rely on size only, it will work 99% of the time, except when you fix a single letter type that won't change the file size... been there.

Links to the challenge reports from others

The Old Computer Challenge V2: day 1

Written by Solène, on 10 July 2022.
Tags: #life #offline #oldcomputerchallenge #nocloud

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1. Introduction §

Today is the beginning of the 2022 Old Computer Challenge, for a week I am now restricted to one hour of Internet access per day.

Old Computer Challenge V2 announcement

2. How do I account time? §

For now, I turned off my smartphone Wi-Fi because it would be hard to account its time.

My main laptop is using the very nice script from our community member prahou.

The script design is smart, it's accounting time and displaying time consumed, it can be described as a machine state like this:


   +------------+                    +----------------------------+
   | wait for   |                    | Accounting time for today  |
   | input      |  Type Enter        | Internet is enabled        |
   |            |------------------->|                            |
   | Internet   |                    | display time used          |
   | offline    |                    | today                      |
   +------------+                    +----------------------------+
          ^                                         v
          |                       press ctrl+C      |
          |       (which is trapped to run a func)  |
          +-----------------------------------------+

As the way to disable / enable internet is specific to every one, the script has two empty fuctions: NETON and NETOFF, they enable or disable Internet access. On my Linux computer I found an easy way to achieve this by adding a bogus default route with a metric 1, bypassing my default route. Because the default route doesn't work my system can't reach the Internet, but it let my LAN in a working state.

My own version of prahou's script (I made some little changes)

3. How's life? §

So far, it's easy to remember I don't have Internet all the time, but with my Internet usage it works fine. I use the script to "start" Internet, check my emails, read IRC channels and reply, and then I disconnect. By using small amount of time, I can achieve most of my needs in less than a minute. However, that wouldn't be practical if I had to download anything big, and people with a fast Internet access (= not me) would have an advantage.

My guess about this first day being easy is that as I don't use any streaming service, I don't need to be connected all the time. All my data are saved locally, and most of my communication needs can be done asynchronously. Even publishing this blog post shouldn't consume more than 20 seconds.

4. Let's go for a week §

I suppose it will be easy to forget about limited Internet time, so it will be best for me to run the accounting script in a terminal (disabling Internet until I manually accept to enable it), and think a bit ahead if I will need more time later so I can be more conservative about time usage.

So far, it's a great experience I enjoy a lot. I hope other participant will enjoy it as much as I do. We will start gathering and aggregating reports soon, so you could enjoy all the reports from our community.

5. It's not late to join §

Despite the challenge officially started today (10th July), it's not late to start it yourself. The important is to have fun, if you want to try, you could just use a chronometer and see if you could hold with only 60 minutes a day.

The Old Computer Challenge V2: back to RTC

Written by Solène, on 01 July 2022.
Tags: #life #offline #oldcomputerchallenge #nocloud

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1. Introduction §

Hello! Let me start straight into the topic: The Old Computer Challenge, second edition!

Some readings if you don't know about the first Old Computer Challenge

The first edition of the challenge consisted into spending a week (during your non-work time) using an old computer, the recommended machine specifications were 1 core and 512 MB of memory at best, however some people enjoyed doing this challenge with other specifications and requirements, and it's fine, the purpose of the challenge is to have fun.

While experimenting the challenge last year, a small but solid community gathered on IRC, we shared tips and our feelings about the challenge, it was very fun and a good opportunity to meet new people. One year later, the community is still there and over the last months we had regular ideas exchange for renewing the challenge.

I didn't want to do the same challenge again, the fun would be spoiled, and it would have a feeling of déjà vu. I recently shared a new idea and many adopted it, and it was clear this would be the main topic of the new challenge.

2. The Old Computer Challenge v2 §

This new challenge will embrace the old time of RTC modems with a monthly time budget. Back in these days, in France at least, people had to subscribe to an ISP for a given price, but you would be able to connect only for 10, 20, 30, 40... hours a month depending on your subscription. Any extra hour was very expensive. We used the Internet the most efficiently possible because it was time limited (and very slow, 4 kB/s at best). Little story, phone lines were not available while a modem was connected, and we had to be careful not to forget to manually disconnect the modem after use, otherwise it would stay connected and wasting the precious Internet time! (and making expensive bills)

The new challenge rules are easy: you are allowed to _connect_ your computer to the Internet for a maximum cumulated time of 1h per day, from 10th to 17th July included. This mean you can connect six times for ten minutes, twice for thirty minutes, or once for one hour in the day.

Remember, the challenge is about having fun and helping you to step back on your computer habits, it's also recommended to share your thoughts and feeling a few times over the challenge week on your usual medias. There is nothing to prove to anyone, if you want to cheat or do the challenge with two or six hours a day, please do as you prefer.

The old computer challenge v2 cover
The old computer challenge v2 cover

This artwork was created by our community member prahou (thanks!), and is under the license CC BY-NC-ND 4.0, you can reuse it as-this. It features a CD because back in the RTC time, ISP were offering CDs to connect to the Internet and subscribe from home, I remember using those as flying discs.

A page gathering the reports from all the participants

3. Time accounting §

While I don't have any implementation yet, here is an ideas list to help you to accounting your Internet time:

  • simple but effective, use airplane mode for Wi-Fi or unplug Ethernet, and use a chronometer when you connect
  • adding/removing the default route can be easier than playing with the firewall and still allow you to use the local network
  • a script that would try a ping every minute and account success in a file with a timestamp, it becomes easy to get information from this
  • some firewall rules you would trigger after a sleep 3600 command
  • define a time slot in your day for the challenge and use a cron job to manipulate the firewall to allow/block network depending on the current time

prahou's shell script counting time and enabling/disabling Internet, you need to modify NETOFF and NETON to adapt to your operating system

4. Frequently asked questions §

4.1. Does it apply on work time? §

No.

4.2. Can I have an exemption? §

If you really need to use the Internet for something, it's up to you. Don't make your life unbearable for a week because of the challenge.

4.3. Does it apply to 1h/day per device? §

No, it's 1h cumulated for all your devices, including smartphones.

4.4. Where is the community? §

We are reachable on #oldcomputerchallenge IRC channel on the Libera.chat network

Website of the libera.chat network and instructions how to connect

However, during the challenge I expect the channel to be quiet because people will be limited to 1h a day.

How I would sell OpenBSD as a salesperson

Written by Solène, on 22 June 2022.
Tags: #openbsd #opensource #business

Comments on Fediverse/Mastodon

1. Introduction §

Let's have fun today. I always wondered how I would sell OpenBSD licences to customers if I was a salesperson.

This text is pure fiction and fun. The OpenBSD project is free of charge and under a libre software licence.

Website of The OpenBSD Project

2. Killer features §

When selling a product, it's always important to talk about the killer features, what makes a product a good one and why it would solve the customer problems.

2.1. Learn once §

If you were to use OpenBSD, you certainly would have a slight learning curve, but then the system is so stable over time that the acquired knowledge would be reused from release to release. Most base tools in OpenBSD are evolving while keeping compatibility with regard to how you administrate them.

Can we say so for the Linux ecosystem which changes its sound and init system every 5 years? Can we say so for Windows which revisites most of its interface at every new release?

Learning OpenBSD is a good investment that will save you time later, so you can use your computer without frustration.

3. Secure by default §

OpenBSD comes with strong security defaults, you don't have to tweak anything, the development did it for you! You can confidently use your OpenBSD computer, and you will be safe from all the bad actors targetting mainstream systems.

Even more, OpenBSD takes care of your privacy and doesn't run any telemetry, doesn't record what you type, doesn't upload any data. The team took care of disabling microphone and webcam by faking their input stream with empty data until you explicitely allow one or the other to record audio/video.

3.1. Community driven §

Because you certainly don't want to suffer from big IT actors decisions affecting your favorite OS, OpenBSD is community driven and take care of not being infecting by big tech agendas. The system is made for the developers, by the developers, and you can use it as a customer! Doesn't this feel great to know the authors use their own software?

3.2. No obsolescence / eco-friendly §

Rest assured that your brand-new computer will still be able to run OpenBSD in 20 years. The team is taking a special care of keeping compatibility for older hardware until it's too hard to find spare components. It's almost a lifetime of system upgrades for your hardware! Are the competitors still supporting Sparc64 and 32-bit PowerPC for a modern computer experience? I don't think so! The installer is still available for floppy disk, I think this says it all!

3.3. Very low maintenance §

As OpenBSD is designed to be highly resilient and so simple that it can't break, be sure you won't waste time fixing problems on your system. With a FREE major update every six months and regular security updates, your system keeps being bulletproof with no more maintenance from you than running the update; more experienced users can even automate this using the built-in and free of charge task scheduler.

3.4. Licencing §

OpenBSD is perfect for people who want to become rich! Think about this, you love your OpenBSD system, and you want to make a product out of it? Perfect! The licencing allows you to make changes to OpenBSD, redistribute it, charge people for it, and you don't even have to show a single line of your product source code to your customers. This is a perfect licencing for people who would like to build proprietary devices based on OpenBSD, a rock solid system.

Against all industry standards, in case you would improve your OpenBSD, you are allowed to make changes to it without losing the warrantly coming with the licensing.

3.5. Technical support §

If you ever need help, you will have direct access for free to the mailing lists of the project, allowing you to exchange directly with the people developping OpenBSD.

3.6. Documentation §

Don't be afraid to jump into OpenBSD from another operating system, we took care of documenting everything you will need. We are very proud of our documentation, and you can even use your OpenBSD system without Internet connectivity and still being able to read the top-notch documentation to configure your system to your needs. No more need to use a search engine to find old blog posts with outdated and inaccurate advice.

3.7. Fast to install §

You can install OpenBSD very fast by just answering to a few questions about the setup. However, you should never need to install OpenBSD more than once so most people will never notice about it. Experimented users can even automate installation to spread OpenBSD to their family without effort.

4. Behind the scenes §

Of course, as a good salesperson, I would have to avoid some topics because this would make the customer lose interest into OpenBSD. However, they could be turned as a positive fact:

  • OpenBSD doesn't support Bluetooth, but you can see this as a security feature. The code was entirely removed from the kernel because Bluetooth is full of traps and could easily leak data over the air. You certainly don't want that?
  • You may think OpenBSD slow performance could hit your productivity, but on the contrary it's a feature that will prevent you from losing focus on what you are currently working on. Think about the Tortoise and the Hare!
  • Maybe your favorite software is proprietary and will not be provided for OpenBSD, then your provider is entirely at fault because they don't want to make their software compliant with OpenBSD strong quality requirements to provide a working binary
  • You may have heard some hardware won't run on OpenBSD, this can happen for very niche hardware. The OpenBSD team is working hard to give you the best experience on a selection of affordable hardware with premium support.

5. Conclusion §

I hope you understood this was a fiction; OpenBSD is free and anyone can use it. It has strength and weaknesses, as always it's important to use the right tool for the right job. The team would be happy to receive contributions from you if you want to improve OpenBSD, by doing so you could help me improve my speech as a saleperson.

"Take my money" meme
"Take my money" meme

Use a gamepad to control mpv video playback

Written by Solène, on 21 June 2022.
Tags: #opensource #unix

Comments on Fediverse/Mastodon

1. Introduction §

This is certainly not a common setup, but I have a laptop plugged on my TV through an external GPU, and it always has a gamepad connected to it. I was curious to see if I could use the gamepad to control mpv when watching videos; it turns out it's possible.

In this text, you will learn how to control mpv using a gamepad / game controller by configuring mpv.

2. Configuration §

All the work will happen in the file ~/.config/mpv/inputs.conf. As mpv uses the SDL framework this gives easy names to the gamepad buttons and axis. For example, forget about brand specific buttons names (A, B, Y, square, triangle etc...), and welcome generic names such as action UP, action DOWN etc...

Here is my own configuration file, comments included:

# left and right (dpad or left stick axis) will move time by 30 seconds increment
GAMEPAD_DPAD_RIGHT seek +30
GAMEPAD_DPAD_LEFT seek -30

# using up/down will move to next/previous chapter if the video supports it
GAMEPAD_DPAD_UP add chapter 1
GAMEPAD_DPAD_DOWN add chapter -1

# button down will pause or resume playback, the "cycle" keyword means there are different states (pause/resume)
GAMEPAD_ACTION_DOWN cycle pause

# button up will switch between windowed or fullscreen
GAMEPAD_ACTION_UP cycle fullscreen

# right trigger will increase playback speed every time it's pressed by 20%
# left trigger resets playback speed
GAMEPAD_RIGHT_TRIGGER multiply speed 1.2
GAMEPAD_LEFT_TRIGGER set speed 1.0

You can find the actions list in mpv man page, or by looking at the sample inputs.conf that should be provided with mpv package.

3. Run mpv §

By default, mpv won't look for gamepad inputs, you need to add --input-gamepad=yes parameter when you run mpv, or add "input-gamepad=yes" as a newline in ~/.config/mpv/mpv.conf mpv configuration file.

If you use a button on the gamepad while mpv is running from a terminal, you will have some debug output showing you which button was pressed, including its name, this is helpful to find the inputs names.

4. Conclusion §

Using the gamepad instead of a dedicated remote is very convenient for me, no extra expense, and it's very fun to use.

How to make a local NixOS cache server

Written by Solène, on 02 June 2022.
Tags: #nixos #unix #bandwidth #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

If like me, you have multiple NixOS system behind the same router, you may want to have a local shared cache to avoid downloading packages multiple time.

This can be done simply by using nginx as a reverse proxy toward the official repository and by enabling caching the result.

nix-binary-cache-proxy project I used as a base

2. Server side configuration §

We will declare a nginx service on the server, using http protocol only to make setup easier. The packages are signed, so their authenticity can't be faked. In this setup, using https would add anonymity which is not much of a concern in a local network, for my use case.

In the following setup, the LAN cache server will be reachable at the address 10.42.42.150, and will be using the DNS resolver 10.42.42.42 every time it needs to reach the upstream server.

  services.nginx = {
    enable = true;
    appendHttpConfig = ''
      proxy_cache_path /tmp/pkgcache levels=1:2 keys_zone=cachecache:100m max_size=20g inactive=365d use_temp_path=off;
      
      # Cache only success status codes; in particular we don't want to cache 404s.
      # See https://serverfault.com/a/690258/128321
      map $status $cache_header {
        200     "public";
        302     "public";
        default "no-cache";
      }
      access_log /var/log/nginx/access.log;
    '';
    
    virtualHosts."10.42.42.150" = {
      locations."/" = {
        root = "/var/public-nix-cache";
        extraConfig = ''
          expires max;
          add_header Cache-Control $cache_header always;
          # Ask the upstream server if a file isn't available locally
          error_page 404 = @fallback;
        '';
      };
      
      extraConfig = ''
        # Using a variable for the upstream endpoint to ensure that it is
        # resolved at runtime as opposed to once when the config file is loaded
        # and then cached forever (we don't want that):
        # see https://tenzer.dk/nginx-with-dynamic-upstreams/
        # This fixes errors like
        #   nginx: [emerg] host not found in upstream "upstream.example.com"
        # when the upstream host is not reachable for a short time when
        # nginx is started.
        resolver 10.42.42.42;
        set $upstream_endpoint http://cache.nixos.org;
      '';
      
      locations."@fallback" = {
        proxyPass = "$upstream_endpoint";
        extraConfig = ''
          proxy_cache cachecache;
          proxy_cache_valid  200 302  60d;
          expires max;
          add_header Cache-Control $cache_header always;
        '';
      };
      
      # We always want to copy cache.nixos.org's nix-cache-info file,
      # and ignore our own, because `nix-push` by default generates one
      # without `Priority` field, and thus that file by default has priority
      # 50 (compared to cache.nixos.org's `Priority: 40`), which will make
      # download clients prefer `cache.nixos.org` over our binary cache.
      locations."= /nix-cache-info" = {
        # Note: This is duplicated with the `@fallback` above,
        # would be nicer if we could redirect to the @fallback instead.
        proxyPass = "$upstream_endpoint";
        extraConfig = ''
          proxy_cache cachecache;
          proxy_cache_valid  200 302  60d;
          expires max;
          add_header Cache-Control $cache_header always;
        '';
      };
    };
  };

Be careful, the default cache is located under /tmp/ but the nginx systemd service is hardened and its /tmp/ is faked in a temporary directory, meaning if you restart nginx you lose the cache. I'd advise using a directory like /var/cache/nginx/ if you want your cache to persist across restarts.

3. Client side configuration §

Using the cache server on a system is really easy. We will define the binary cache to our new local server, the official cache is silently added so we don't have to list it.

  nix.binaryCaches = [ "http://10.42.42.150/" ];

Note that you have to use this on the cache server itself if you want the system to use the cache for its own needs.

4. Conclusion §

Using a local cache can save a lot of bandwidth when you have more than one computer at home (or if you extensively use nix-shell and often run the garbage collector). Due to NixOS packages names being unique, we won't have any issues of a newer package version behind hidden by a local copy cached, which make the setup really easy.

Creating a NixOS thin gaming client live USB

Written by Solène, on 20 May 2022.
Tags: #nixos #gaming

Comments on Fediverse/Mastodon

1. Introduction §

This article will cover a use case I suppose very personal, but I love the way I solved it so let me share this story.

I'm a gamer, mostly on computer, but I have a big rig running Windows because many games still don't work well with Linux, but I also play video games on my Linux laptop. Unfortunately, my laptop only has an intel integrated graphic card, so many games won't run well enough to be played, so I'm using an external GPU for some games. But it's not ideal, the eGPU is big (think of it as a big shoes box), doesn't have mouse/keyboard/usb connectors, so I've put it into another room with a screen at a height to play while standing up, controller in hands. This doesn't solve everything, but I can play most games running on it and allowing a controller.

But if I install a game on both the big rig and the laptop, I have to manually sync the saves (I'm buying most of the games on GOG which doesn't have a Linux client to sync saves), it's highly boring and error-prone.

So, thanks to NixOS, I made a recipe to generate a USB live media to play on the big rig, using the data from the laptop, so it's acting as a thin client. The idea of a read only media to boot from is very nice, because USB memory sticks are terrible if you try to install Linux on them (I tried many times, it always ended with I/O errors quickly) and there is exactly what you need, generated from a declarative file.

What does it solve concretely? I can play some games on my laptop anywhere on the small screen, I can also play with my eGPU on the standing desk, but now I can also play all the installed games from the big rig with mouse/keyboard/144hz screen.

2. What's in the live image? §

The generated ISO (USB capable) should come with a desktop environment like Xfce, Nvidia drivers, Steam, Lutris, Minigalaxy and some other programs I like to use, I keep the programs list minimal because I could still use nix-shell to run a program later.

For the system configuration, I declare the user "gaming" with the same uid as the user on my laptop, and use an NFS mount at boot time.

I'm not using Network Manager because I need the system to get an IP before connecting to a user account.

3. The code §

I'll be using flakes for this, it makes pinning so much easier.

I have two files, "flake.nix" and "iso.nix" in the same directory.

flake.nix file:

{
  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";

  };

  outputs = { self, nixpkgs, ... }@inputs:
    let
      system = "x86_64-linux";

      pkgs = import nixpkgs { inherit system; config = { allowUnfree = true; }; };
      lib = nixpkgs.lib;

    in
    {

      nixosConfigurations.isoimage = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          ./iso.nix
          "${nixpkgs}/nixos/modules/installer/cd-dvd/installation-cd-base.nix"
        ];
      };

    };
}

And iso.nix file:

{ config, pkgs, ... }:
{

  # compress 6x faster than default
  # but iso is 15% bigger
  # tradeoff acceptable because we don't want to distribute
  # default is xz which is very slow
  isoImage.squashfsCompression = "zstd -Xcompression-level 6";
  
  # my azerty keyboard
  i18n.defaultLocale = "fr_FR.UTF-8";
  services.xserver.layout = "fr";
  console = {
    keyMap = "fr";
  };
  
  # xanmod kernel for better performance
  # see https://xanmod.org/
  boot.kernelPackages = pkgs.linuxPackages_xanmod;
  
  # prevent GPU to stay at 100% performance
  hardware.nvidia.powerManagement.enable = true;
  
  # sound support
  hardware.pulseaudio.enable = true;
 
  # getting IP from dhcp
  # no network manager
  networking.dhcpcd.enable = true;
  networking.hostName = "biggy"; # Define your hostname.
  networking.wireless.enable = false;

  # many programs I use are under a non-free licence
  nixpkgs.config.allowUnfree = true;

  # enable steam
  programs.steam.enable = true;

  # enable ACPI
  services.acpid.enable = true;

  # thermal CPU management
  services.thermald.enable = true;

  # enable XFCE, nvidia driver and autologin
  services.xserver.desktopManager.xfce.enable = true;
  services.xserver.displayManager.lightdm.autoLogin.timeout = 10;
  services.xserver.displayManager.lightdm.enable = true;
  services.xserver.enable = true;
  services.xserver.libinput.enable = true;
  services.xserver.videoDrivers = [ "nvidia" ];
  services.xserver.xkbOptions = "eurosign:e";

  time.timeZone = "Europe/Paris";

  # declare the gaming user and its fixed password
  users.mutableUsers = false;
  users.users.gaming.initialHashedPassword = "$6$bVayIA6aEVMCIGaX$FYkalbiet783049zEfpugGjZ167XxirQ19vk63t.GSRjzxw74rRi6IcpyEdeSuNTHSxi3q1xsaZkzy6clqBU4b0";
  users.users.gaming = {
    isNormalUser = true;
    shell = pkgs.fish;
    uid = 1001;
    extraGroups = [ "networkmanager" "video" ];
  };
  services.xserver.displayManager.autoLogin = {
    enable = true;
    user = "gaming";
  };

  # mount the NFS before login
  systemd.services.mount-gaming = {
    path = with pkgs; [ nfs-utils ];
    serviceConfig.Type = "oneshot";
    script = ''
      mount.nfs -o fsc,nfsvers=4.2,wsize=1048576,rsize=1048576,async,noatime t470-eth.local:/home/jeux/ /home/jeux/
    '';
    before = [ "display-manager.service" ];
    wantedBy = [ "display-manager.service" ];
    after = [ "network-online.target" ];
  };

  # useful packages
  environment.systemPackages = with pkgs; [
    bwm_ng
    chiaki
    dunst # for notify-send required in Dead Cells
    file
    fzf
    kakoune
    libstrangle
    lutris
    mangohud
    minigalaxy
    ncdu
    nfs-utils
    steam
    steam-run
    tmux
    unzip
    vlc
    xorg.libXcursor
    zip
  ];

}

Then I can update the sources using "nix flake lock --update-input nixpkgs", that will tell you the date of the nixpkgs repository image you are using, and you can compare the dates for updating. I recommend using a program like git to keep track of your files, if you see a failure with a more recent nixpkgs after the lock update, you can have fun pinpointing the issue and reporting it, or restoring the lock to the previous version and be able to continue building ISOs.

You can build the iso with the command "nix build .#nixosConfigurations.isoimage.config.system.build.isoImage", this will create a symlink "result" in the directory, containing the ISO that you can burn on a disk or copy to a memory stick using dd.

4. Server side §

Of course, because I'm using NFS to share the data, I need to configure my laptop to serves the files over NFS, this is easy to achieve, just add the following code to your "configuration.nix" file and rebuild the system:

services.nfs.server.enable = true;
services.nfs.server.exports = ''
  /home/gaming 10.42.42.141(rw,nohide,insecure,no_subtree_check)
'';

If like me you are using the firewall, I'd recommend opening the NFS 4.2 port (TCP/2049) on the Ethernet interface only:

networking.firewall.enable = true;
networking.firewall.allowedTCPPorts = [ ];
networking.firewall.allowedUDPPorts = [ ];
networking.firewall.interfaces.enp0s31f6.allowedTCPPorts = [ 2049 ];

In this case, you can see my NFS client is 10.42.42.141, and previously the NFS server was referred to as laptop-ethernet.local which I declare in my LAN unbound DNS server.

You could make a specialisation for the NFS server part, so it would only be enabled when you choose this option at boot.

5. NFS performance improvement §

If you have a few GB of spare memory on the gaming computer, you can enable cachefilesd, a service that will cache some NFS accesses to make the experience even smoother. You need memory because the cache will have to be stored in the tmpfs and it needs a few gigabytes to be useful.

If you want to enable it, just add the code to the iso.nix file, this will create a 10 MB * 300 cache disk. As tmpfs lacks user_xattr mount option, we need to create a raw disk on the tmpfs root partition and format it with ext4, then mount on the fscache directory used by cachefilesd.

services.cachefilesd.enable = true;
services.cachefilesd.extraConfig = ''
  brun 6%
  bcull 3%
  bstop 1%
  frun 6%
  fcull 3%
  fstop 1%
'';

# hints from http://www.indimon.co.uk/2016/cachefilesd-on-tmpfs/
systemd.services.tmpfs-cache = {
  path = with pkgs; [ e2fsprogs busybox ];
  serviceConfig.Type = "oneshot";
  script = '' 
    if [ ! -f /disk0 ]; then 
      dd if=/dev/zero of=/disk0 bs=10M count=600 
      echo 'y' | mkfs.ext4 /disk0 
    fi 
    mkdir -p /var/cache/fscache 
    mount | grep fscache || mount /disk0 /var/cache/fscache -t ext4 -o loop,user_xattr 
  '';
  before = [ "cachefilesd.service" ];
  wantedBy = [ "cachefilesd.service" ];
};

6. Security consideration §

Opening an NFS server on the network must be done only in a safe LAN, however I don't consider my gaming account to contain any important secret, but it would be bad if someone on the LAN mount it and delete all the files.

However, there are two NFS alternatives that could be used:

  • using sshfs using an SSH key that you transport on another media, but it's tedious for a local LAN, I've been surprised to see sshfs performance were nearly as good as NFS!
  • using sshfs using a password, you could only open ssh to the LAN, which would make security acceptable in my opinion
  • using WireGuard to establish a VPN between the client and the server and use NFS on top of it, but the secret of the tunnel would be in the USB memory stick so better not have it stolen

7. Size optimization §

The generated ISO can be reduced in size by removing some packages.

7.1. Gnome §

for example Gnome comes with orca which will bring many dependencies for text-to-speech. You can easily exclude many Gnome packages.

environment.gnome.excludePackages = with pkgs.gnome; [
  pkgs.orca
  epiphany
  yelp
  totem
  gnome-weather
  gnome-calendar
  gnome-contacts
  gnome-logs
  gnome-maps
  gnome-music
  pkgs.gnome-photos
];

7.2. Wine §

I found that Wine came with the Windows compiler as a dependency, but yet it doesn't seem useful for running games in Lutris.

NixOS discourse: Wine installing mingw32 compiler?

It's possible to rebuild Wine used by Lutris without support for the mingw compiler, replace the lutris line in the "systemPackages" list with the following code:

(lutris-free.override {
  lutris-unwrapped = lutris-unwrapped.override {
    wine = wineWowPackages.staging.override {
      mingwSupport = false;
    };
  };
})

Note that I'm using lutris-free which doesn't support Steam because it makes it a bit lighter and I don't need to manage my Steam games with Lutris.

8. Possible improvements §

It could be possible to try getting a package from the nix-store on the NFS server before trying cache.nixos.org which would improve bandwidth usage, it's easy to achieve but yet I need to try it in this context.

9. Issue §

I found Steam games running with Proton are slow to start. I made a bug report on the Steam Linux client github.

Github: Proton games takes around 5 minutes to start from a network share

This can be solved partially by mounting ~/.local/share/Steam/steamapps/common/SteamLinuxRuntime_soldier/var as tmpfs, it will uses less than 650MB.

10. Conclusion §

I really love this setup, I can backup my games and saves from the laptop, play on the laptop, but now I can extend all this with a bigger and more comfortable setup. The USB live media doesn't take long to be copied to a USB memory stick, so in case one is defective, I can just recopy the image. The live media can be booted all in memory then be unplugged, this gives a crazy fast responsive desktop and can't be altered.

My previous attempts at installing Linux on an USB memory stick all gave bad results, it was extremely slow, i/o errors were common enough that the system became unusable after a few hours. I could add a small partition to one disk of the big rig or add a new disk, but this will increase the maintenance of a system that doesn't do much.

Using a game engine to write a graphical interface to the OpenBSD package manager

Written by Solène, on 05 May 2022.
Tags: #openbsd #godot #opensource

Comments on Fediverse/Mastodon

1. Introduction §

I'm really trying hard to lower the barrier entry to OpenBSD, I realize most of my efforts are toward making OpenBSD easier.

One thing I often mumbled about on OpenBSD was the lack of a user interface to browse packages and install them, there was a console program named pkg_mgr, but I never got it to work. Of course, I'm totally able to install packages using the command line, but I like to stroll looking for packages I wouldn't know about, a GUI is perfect for doing so, and is also useful for people less comfortable with the command line.

So, today, I made a graphical user interface (GUI) using OpenBSD, using a game engine. Don't worry, all the packages operations are delegated to pkg_add and pkg_delete because they are doing they job fine.

OpenBSD AppManager project website

AppManager main menu
AppManager main menu
AppManager giving a summary of changes
AppManager giving a summary of changes

2. What is it doing? §

The purpose of this program is simple, display the list of available packages, highlight in yellow the one you have installed on your system, and let you select new packages to install or installed packages to remove.

It features a search input instead of displaying a blunt list of a dozen of thousands of entries. The development was made on my Thinkpad T400 (core 2 duo), performance are excellent.

One simple feature I'm proud of is the automatic classification of packages into three categories: GUI programs, terminal/console user interface programs and others. While this is not perfect because we don't have this metadata anywhere, I'm reusing the dependencies' information to guess in which category each package belongs, so far it's giving great results.

3. About the engine §

I rarely write GUI application because it's often very tedious and give poor results, so the ratio time/result is very bad. I've been playing with the Godot game engine for a week now, and I was astonished when I've been told the engine editor is done using the engine itself. As it was blazing fast and easy to make small games, I wondered if this would be suitable for a simple program like a package manager interface.

First thing I checked was if it was supporting sqlite or json data natively without much work. This was important as the data used to query the package list is originally found in a sqlite database provided by the sqlports package, however the sqlite support was only available through 3rd party code while JSON was natively supported. When writing then simple script converting data from the sqlite database into a json, I took the opportunity to add the logic to determine if it's a GUI or a TUI (Terminal UI) and make the data format very easy to reuse.

Finally, I got a proof of concept within 2h, it was able to install packages from a list. Then I added support for displaying already installed packages and then to delete packages. The polishing of the interfaces took the most time, but the whole project didn't take more than 8h which is unbelievable for me.

4. Conclusion §

From today, I'll seriously think about using Godot for writing GUI application, did I say it's cross platform? AppManager can be run on Linux or Windows (given you have pkg.json), except it will just fail at installing packages, but the whole UI works.

Thinking about it, it could be easy to reuse it for another package manager.

Managing OpenBSD installed packages declaratively

Written by Solène, on 05 May 2022.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

I wrote a simple utility to manage OpenBSD packages on a system using a declarative way.

pkgset git repository

Instead of running many pkg_add or pkg_delete commands to manage my packages, now I can use a configuration file (allowing includes) to define which package should be installed, and the installed but not listed packages should be removed.

After using NixOS too long, it's a must have for me to manage packages this way.

2. How does it work? §

pkgset works by marking extra packages as "auto installed" (the opposite is manually installed, see pkg_info -m), and by installing missing packages. After those steps, pkgset runs "pkg_delete -a" to remove unused packages (the one marked as auto installed) if they are not a dependency of another required package.

3. How to install? §

The installation is easy, download the sources and run make install as root, it will install pkgset and its man page on your system.

$ git clone https://tildegit.org/solene/pkgset.git
$ cd pkgset
$ doas make install

4. Configuration file example §

Here is the /etc/pkgset.conf file on my laptop.

borgbackup--%1.2
bwm-ng
fish
fzf
git
git-annex
gnupg
godot
kakoune
musikcube
ncdu
rlwrap
sbcl
vim--no_x11
vlc
xclip
xfce
xfce-extras
yacreader

5. Limitations §

The only "issue" with pkgset is that for some packages that "pkg_add" may find ambiguous due to multiples versions or favors available without a default one, you must define the exact package version/flavor you want to install.

6. Risks §

If you use it incorrectly, running pkgset doesn't have more risks than losing some or all installed packages.

7. Why not use pkg_add -l ? §

I know pkg_add as an option to install packages from a list, but it won't remove the extra packages. I may look at adding the "pkgset" feature to pkg_add one day maybe.

How to contribute to the OpenBSD project

Written by Solène, on 03 May 2022.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Intro §

You like OpenBSD? Then, I'm quite sure you can contribute to it! Let me explain the many ways your skills can be used to improve the project and contribute back.

Official FAQ section about how to support the Project

2. Contributing to OpenBSD §

I proposed to update the official FAQ with this content, but it has been dismissed, so I'm posting it here as I'm convinced it's valuable.

2.1. Writing and reviewing code §

Programmers who enjoy writing operating systems are naturally always welcome. The team would appreciate your skills on the base system, kernel, userland.

How create a diff to share a change with other

There is also place for volunteers willing to help at packaging and maintaing software up to date in our ports tree.

The porter guide

2.2. Use the development version §

Switch your systems to the branch -current and report system or packages regressions. With more users testing the development version, the releases are more likely to be bug free. Why not join the

What is -current, how to use it

It's also important to use the packages regularly on the development branch to report any issue.

FAQ guide to testing packages

Try OpenBSD on as many hardware as you can, send a bug report if you find incompatibility or regressions.

How to write an useful bug report

Supported hardware platform

2.3. Documentation §

Help maintain documentation by submitting new FAQ material to the misc@openbsd.org mailing list.

Challenging the documentation accuracy and relevance on a regular basis is a good way to contribute for everyone.

2.4. Community §

Follow the mailing lists, you may be able to help answer questions from other users. This is also a good opportunity to proofread submitted changes proposed by others or to try those and report how it works for you.

The OpenBSD mailing lists

Form or join a local group and get your friends hooked on OpenBSD.

List of OpenBSD user groups

Spread the word on social networks, show the project under a good light, share your experiences and your use cases. OpenBSD is definitely not a niche operating system anymore.

Make a case to your employer for using OpenBSD at work. If you're a student, talk to your professors about using OpenBSD as a learning tool for Computer Science or Engineering courses.

2.5. Donate money or hardware §

The project has a constant need for cash to pay for equipment, network connectivity, etc. Even small donations make a profound difference, donating money or hardware is important.

Donating money

Donate equipment and parts (wishlist)

Blog post: just having fun making games

Written by Solène, on 29 April 2022.
Tags: #gaming #godot #life

Comments on Fediverse/Mastodon

Hi! Just a short blog entry about making games.

I've been enjoying learning how to use a game engine for three days now. I also published my two last days on the itch.io platform for independant video games. I'm experimenting a lot with various ideas, a new game must be different than the other to try new mechanics, new features and new gameplay.

This is absolutely refreshing to have a tool in hand that let me create interactive content, this is really fantastic. I wish I studied this earlier.

Despite my games being very short and simplistic, I'm quite proud of the accomplished work. If someone in the world had fun with them even for 20 seconds, this is a win for me.

My profile on itch.io (for potential future game publications)

Writing my first OpenBSD game using Godot

Written by Solène, on 28 April 2022.
Tags: #gaming #openbsd #godot

Comments on Fediverse/Mastodon

1. Introduction §

I'm a huge fan of video games but never really thought about writing one. Well, this crossed my mind a few times, but I don't know anything about writing a GUI software or using OpenGL, but a few days ago I discovered the open source game engine Godot.

This game engine is a full-featured tool allowing to easily write 2D or 3D games that are portables on Android, Mac, Windows, Linux, HTML5 (using WebASM) and operating systems where the Godot engine is available, like OpenBSD.

Godot engine project website

2. Learning §

Godot offers a GUI to write games, the GUI itself being a Godot game, it's full featured and come with a code editor, documentation, 2D/3D views, animation, tile set management, and much more.

The documentation is well written and gives introduction to the concepts, and then will just teach you how to write a simple 2D game! It only took me a couple of hours to be able to start creating my very own first game and getting the grasps.

Godot documentation

I had no experience into writing games but only programming experience. The documentation is excellent and give simple examples that can be easily reused thanks to the way Godot is designed. The forums are also a good way to find a solution for common problems.

3. Demo §

I wrote a simple game, OpenBSD themed, especially themed against its 6.8 version for which the artwork is dedicated to the movie "Hackers". It took me like 8 hours I think to write it, it's long, but I didn't see time passing at all, and I learned a lot. I have a very interesting game in my mind, but I need to learn a lot more to be able to do it, so starting with simple games is a nice training for me.

It's easy to play and fun (I hope so), give it a try!

Play it on the web browser

Play it on Linux

Play it on Windows

If you wish to play on OpenBSD or any other operating system having Godot, download the Linux binary and run "godot --main-pack puffy-bubble.x86_64" and enjoy.

I chose a neon style to fit to the theme, it's certainly not everyone's taste :)

A screenshot of the game, displaying a simple maze in the neon style, a Puffy mascot, the text "Hack the planet" and a bubble on the top of the maze.
A screenshot of the game, displaying a simple maze in the neon style, a Puffy mascot, the text "Hack the planet" and a bubble on the top of the maze.

Routing a specific user on a specific network interface on Linux

Written by Solène, on 23 April 2022.
Tags: #linux #networking #security

Comments on Fediverse/Mastodon

1. Introduction §

I have a special network need on Linux, I must have a single user going through specific VPN tunnel. This can't be done using a different metric for the VPN or by telling the program to bind on a specific interface.

2. How does it work §

The setup is easy once you find how to proceed on Linux: we define a new routing table named 42 and add a rule assigning user with uid 1002 to this routing table. It's important to declare the VPN default route on the exact same table to make it work.

#!/bin/sh

REMOTEGW=YOUR_VPN_REMOTE_GATEWAY_IP
LOCALIP=YOUR_VPN_LOCAL_IP
INTERFACE=tun0

ip route add table 42 $REMOTEGW dev tun0
ip route add table 42 default via $REMOTEGW dev tun0 src $LOCALIP
ip rule add pref 500 uidrange 1002-1002 lookup 42
ip rule add from $LOCALIP  table 42

3. Conclusion §

It's quite complicated to achieve this on Linux because there are many ways to proceed like netns (network namespace), iptables or vrf but the routing solution is quite elegant, and the documentation are never obvious for this use case.

I'd like to thank @loweel@bbs.keinpfusch.net from the Fediverse for giving me the first bits about ip rules and using a different route table.

Video guide to install OpenBSD 7.1 with the GNOME desktop

Written by Solène, on 23 April 2022.
Tags: #how-to #openbsd #video #gnome

Comments on Fediverse/Mastodon

1. Introduction §

I asked the community recently if they would like to have a video tutorial about installing OpenBSD, many people answered yes so here it is! I hope you will enjoy it, I'm quite happy of the result while I'm not myself fan of watching video tutorials.

2. The links §

The videos are published on Peertube, but you are free to reupload them on YouTube if you want to, the licence permits it. I won't publish on YouTube because I don't want to feed this platform.

The English video has Italian subtitles that have been provided by a fellow reader.

[English] Guide to install OpenBSD 7.1 with the GNOME desktop

[French] Guide vidéo d'installation d'OpenBSD de A à Z avec l'environnement GNOME

3. Why not having used a VM? §

I really wanted to use a real hardware (an IBM ThinkPad T400 with an old Core 2 Duo) instead of a virtual machine because it feels a lot more real (WoW :D) and has real world quirks like firmwares that would be avoided in a VM.

4. Youtube Links §

If you prefer YouTube, someone republished the video on this Google proprietary platform.

[YOUTUBE] [English] Guide to install OpenBSD 7.1 with the GNOME desktop

[YOUTUBE] [French] Guide vidéo d'installation d'OpenBSD de A à Z avec l'environnement GNOME

5. Making-off §

I rarely make videos, and it was a first time for me to create this, so I wanted to share about how I made it because it was very amateurish and weird :D

My first setup trying to record the screen of a laptop using another laptop and an USB camera, it didn't work well

My first setup trying to record the screen of a laptop using another laptop and an USB camera, it didn
My first setup trying to record the screen of a laptop using another laptop and an USB camera, it didn't work well

My second setup, with a GoPro camera more or less correctly aligned with the laptop screen

My second setup, with a GoPro camera more or less correctly aligned with the laptop screen
My second setup, with a GoPro camera more or less correctly aligned with the laptop screen

The first part on Linux was recorded locally with ffmpeg from the T400 computer, the rest is recorded with the GoPro camera, I applied a few filters with the shotcut video editing software to flatten the picture (the lens is crazy on the GoPro).

I spent like 8 hours to create the video, most of the time was editing, blurring my Wi-Fi password, adjusting the speed of the sequences, and once the video was done I recorded my audio comment (using a USB Rode microphone) while watching it, I did it in English and in French, and used shotcut again to sync the audio with the video and merge them together.

Reduce httpd web server bandwidth usage by serving compressed files

Written by Solène, on 22 April 2022.
Tags: #openbsd #selfhosting #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

When reaching a website, most web browsers will send a header (some metadata about the requestion) informing the web server that you supported compressed content. In OpenBSD 7.1, the httpd web server received a new feature allowing it to serves a pre-compressed file of a requested file if the web browser supports compression. The benefits are a bandwidth usage reduced by 2x to 10x depending on the file content, this is particularly interesting for people who self-host and for high traffic websites.

2. Configuration §

In your httpd.conf, in a server block add the "gzip-static" keyword, save the file and reload the httpd service.

A simple server block would look like this:

server "perso.pw" {
        root "/htdocs/solene"
        listen on * port 80
        gzip-static
}

3. Creating the files §

In addition to this change, I added a new flag to the gzip command to easily compress files while keeping the original files. Run "gzip -k" on the files you want to serve compressed when the clients support the feature.

It's best to compress text files, such as HTML, JS or CSS for the most commons. Compressing binary files like archives, pictures, audio or videos files won't provide any benefit.

4. How does it work? §

When the client connects to the httpd server requesting "foobar.html", if gzip-static is used for this location/server, httpd will look for a file named "foobar.html.gz" that is not older than "foobar.html". When found, "foobar.html.gz" is transparently transferred to the client requesting "foobar.html".

Take care to regenerate the gz files when you update the original files, remember that the gz files must be newer to be used.

5. Conclusion §

This is for me a major milestone for using httpd in self-hosting and with static websites. We battle tested this change with the webzine server often hitting big news websites leading to many people visiting the website in a short time span, this drastically reduced the bandwidth usage of the server, allowing it to support more clients per second.

OpenBSD 7.1: fan noise and high temperature solution

Written by Solène, on 21 April 2022.
Tags: #openbsd #obsdfreqd #openbsd71

Comments on Fediverse/Mastodon

1. Introduction §

OpenBSD 7.1 has been released with a change that will set the CPU to max speed when plugged to the wall. This brings better performance and entirely let the CPU and mainboard do the frequency throttling.

However, it may doesn't throttle well for some users, resulting in huge power usage even when idle, heat from the CPU and also fan noise.

As the usual "automatic" frequency scheduling mode is no longer available when connected to powergrid, I wrote a simple utility to manage the frequency when the system is plugged to the wall, I took the opportunity to improve it, giving better performance than the previous automatic mode, but also giving more battery life when using on a laptop on battery.

obsdfreqd project page

2. Installation §

Since OpenBSD 7.2 obsdfreqd is available as a packge. An extra important step is to remove the automatic mode in apmd which would kill obsdfreqd, you can keep apmd for its ability to run commands on resume/suspend etc...

pkg_add obsdfreqd
rcctl ls on | grep ^apmd && rcctl set apmd flags -L && rcctl restart apmd
rcctl enable obsdfreqd
rcctl start obsdfreqd

3. Configuration §

No configuration are required, it works out of the box with a battery saving profile when on battery and a performance profile when connected to power.

If you feel adventurous, obsdfreqd man page will give you information about all the parameters available if you want to tailor yourself a specific profile.

Note that obsdfreqd can target a specific temperature limit using -T parameter, see the man page for explanations.

4. FAQ §

Using hw.perfpolicy="auto" sysctl won't help, the kernel code entirely bypass the frequency management if the system is not running on battery.

sched_bsd.c line shipped in OpenBSD 7.1

Using apmd -A doesn't solve the issue because apmd was simply setting the sysctl hw.perfpolicy to auto, which as explained above set the frequency to full speed when not on battery.

Operating systems battle: OpenBSD vs NixOS

Written by Solène, on 18 April 2022.
Tags: #openbsd #nixos #life #opensource

Comments on Fediverse/Mastodon

1. Introduction §

While I'm an OpenBSD contributor, I also enjoy using Linux especially the NixOS distribution which I consider a system apart from the other Linux distributions because of how different it is. Because I use both, I have two SSDs in my laptop with each system installed and I can jump from one to another depending on the task I'm doing or which I want to use.

My main system, the one with all my data, is OpenBSD, unfortunately the lack of an interoperable and good file system between NixOS and OpenBSD make it difficult to share data between them without using a network storage offering a protocol they have in common.

2. OpenBSD and NixOS §

Let me quickly introduce the two operating systems if you don't know them.

OpenBSD is a 25+ years old fork of NetBSD, it's full of history and a solid system, it's also the place where OpenSSH or tmux are developed. It's a BSD system with its own kernel and own drivers, it's not related to Linux but will share most of well known open source programs you can have on Linux, they are provided as packages (programs such as GIMP, Libreoffice, Firefox, Chromium etc...). The whole OpenBSD system (kernel, drivers, userland and packages) is managed by a team of approximately 150 persons (without counting people sending updates and who don't have a commit access).

The OpenBSD project website

NixOS will be soon a 20 years old Linux distribution based on the nix package manager. It's offering a new approach to system management, based on reproducible builds and declarative configurations, basically you define how your computer should be configured (packages, services, name, users etc..) in a configuration file and "build" the system to configure itself, if you share this configuration file on another computer, you should be able to reproduce the exact same system. Packages are not installed in a standard file hierarchy but each package files are stored into a dedicated directory and the users profiles are made of symbolic links and many environment variables to permit programs to find libraries or dependencies, for example the path to Firefox may look like something like /nix/store/b6gvzjyb2pg0kjfwrjmg1vfhh54ad73z-firefox-33.1/bin/firefox.

The NixOS project website

NixOS wiki: How Nix works

2.1. Performance §

OpenBSD is lacking hardware acceleration for encoding/decoding video, this make it a lot slower when working with videos.

Interactive desktop usage and I/O also feel slower on OpenBSD, on the other hand the Linux kernel used in NixOS benefits from many people working full time at improving its performance, we have to admit the efforts pay off.

Although OpenBSD is slower than Linux, it's actually usable for most tasks one may need to achieve.

2.2. Hardware support §

OpenBSD doesn't support as many devices as NixOS and its Linux kernel. On NixOS I can use an external NVIDIA card using a thunderbolt case, OpenBSD doesn't have support for this case nor has it a driver for NVIDIA cards (which is mostly NVIDIA's fault for not providing documentation).

However, OpenBSD barely requires any configuration to work, if the hardware is supported, it will work.

Finally, OpenBSD can be used on old computers from various architectures, like i386, old Apple powerpc, risc, arm, while NixOS is only focusing on modern hardware such as Amd64 and Arm64.

2.3. Software choice §

Both systems provide a huge packages set, but the one from Nix has more choice. It's not that bad on the OpenBSD side though, most common packages are available and often with a recent version, I also found many times a package available in OpenBSD but not in Nix.

Most notably, I feel the quality of OpenBSD packages is slightly higher than on Nix, they have less issues (Nix packages sometimes have issues that may be related to nix unusual file hierarchy) and are sometimes patched to have better defaults (for instance I'm thinking of disabling network accesses opened by default in some GUI applications).

Both of them make a new release every six months, but while OpenBSD only backport packages security fixes for its latest release, NixOS provides a lot more updates to its packages for the release users.

Updating packages is painless on OpenBSD and NixOS, but it's easier to find which version you are currently using on OpenBSD. This may be because I don't know enough the nix shell but I find it very hard to know if I'm actually using a program that has been updated (after a CVE I often check that) or if it's not.

OpenBSD packages list

NixOS packages list

2.4. Network §

Network is certainly the area where OpenBSD is the most well-known, its firewall Packet Filter is easy to use/configure and efficient. OpenBSD provides mechanisms such as routing tables/domains to assign a network interface to an entire separated network, allowing to expose a program/user to a specific interface reliably, I didn't find how to achieve this on Linux yet. OpenBSD comes with all the required daemons to manage a network (dhcp, slaacd, rpki, email, http, NAT, ftp, tftp etc...) within its base system.

The performance when dealing with network throughput may be sub-par on OpenBSD compared to Linux but for the average user or server it's fine, it will mostly depend on the network card used and its driver support.

I don't really enjoy playing with network on Linux as I find it very complicated, I never found how to aggregate wifi and Ethernet interfaces to transparently switch from one to the other when I (un)plug the rj45 cable on my laptop, doing this is easy to achieve on OpenBSD (I don't enjoy losing all my TCP connections when moving the laptop around).

2.5. Maintenance §

The maintenance topic will be very personal, for a personal workstation/server case and not a farm of hundreds of servers.

OpenBSD doesn't change much, it has a new release every six months but the upgrades are always easy to handle, most corner cases are documented in the upgrade guide and I'm ALWAYS confident when I have to update an OpenBSD system.

NixOS is also easy to update and keep clean, I never had any issue when upgrading yet and it would still be possible to rollback to the previous version in case something is going wrong.

I can say they have both a different approach but they both work well.

2.6. Documentation §

I have to say the NixOS documentation is rather huge but yet not always useful. There is a nice man page named "configuration.nix" giving all the options to parameter a system, but it's generated from the Nix code and is often lacking explanations in addition to describe an API. There are also a few guides and manual available on NixOS website but they are either redundant or not really describing how to solve real world problems.

NixOS documentation

On the OpenBSD side, the website provides a simple "Frequently Asked Questions" section for some use case, and then all the system and its internal are detailed in very well written man pages, it may feel unfriendly or complicated at first but once you taste the OpenBSD man pages you easily get sad when looking at another documentation. If you had to setup an OpenBSD system for some task relying on components from the base system (= not packages), I'm confident to say you could do it offline with only the man pages. OpenBSD is not a system that you find its documentation on various forums or github gists, while I often feel this with NixOS :(

OpenBSD FAQ

OpenBSD man pages

2.7. Contributing §

I would say NixOS have a modern contribution system, it relies on github and a bot automatically do many checks to the contributions, helping contributors to check their work quickly without "wasting" the time of someone who would have to read every submitted code.

OpenBSD is doing exactly that, changes to the code are done on a mailing list, only between humans. It doesn't scale very well but the human contact will give better explanations than a bot, but this is when your work is interesting someone who want to spend time on it, sometimes you will never get any feedback and it's a bit sad we are losing updates and contributors because of this.

3. Conclusion §

I can't say one is better to the other nor that one is doing absolutely better at one task.

My love for OpenBSD may come from its small community, made of humans that like working on something different. I know how OpenBSD works, when something is wrong it's easy to debug because the system has been kept relatively simple. It's painless, when your hardware is supported, it just works fine. The default configuration is good and I don't have to worry about it.

But I also love NixOS, it's adventurous, it offers a new experience (transactional updates, reproducibility) that I feel are the future of computing, but it also make the whole very complicated to understand and debug. It's a huge piece of software that could be bend to many forms given you are a good Nix arcanist.

I'd be happy to hear about your experiences with regards to OpenBSD and NixOS, feel free to write me (mastodon or email) about this!

Keep your OpenBSD system cool with obsdfreqd

Written by Solène, on 21 March 2022.
Tags: #openbsd #power

Comments on Fediverse/Mastodon

1. Introduction §

Last week I wrote a system daemon to manage the CPU frequency from userland, entirely bypassing the kernel automatic mode. While this was more of a toy at first because I only implemented the same automatic mode used in the kernel but with all the variables being easily changed, I found it valuable for many use case to improve battery life or even temperature.

The coolest feature I added today is to support a maximum temperature and let the program do its best to keep the CPU temperature below the limit.

obsdfreqd project page

2. Installation §

- pkg_add obsdfreqd since OpenBSD 7.2

3. Results §

A nice benchmark to run was to start the compilation of the rust package with all the four cores of my T470 laptop and run obsdfreqd with various temperature limits and see how it goes. The program did a good job at reducing the CPU frequency to keep the temperature around the threshold.

Diagram of benchmark results of various temperature limitation
Diagram of benchmark results of various temperature limitation

4. Conclusion §

While this is ultimately not a replacement for the in-kernel frequency scheduler, it can be used to keep a computer a lot cooler or make a system comply with some specific requirements (performance for given battery life or maximum temperature).

The customization is so that you can have various settings depending if the system is running on battery or not, which can be tailored to suit every kind of user. The defaults are made to provide good performance when on AC, and provide a balanced performance/battery life mode when on battery.

Reproducible clean $HOME in OpenBSD using impermanence

Written by Solène, on 15 March 2022.
Tags: #openbsd #reproducible #nixos #unix

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1. Introduction §

Let me present you my latest project: home-impermanence, under this name is a reference to the NixOS community project impermanence. The name may not be obvious about what it is doing, let me explain.

NixOS wiki about Impermanence, a community module

home-impermanence for OpenBSD

The original goal of impermanence in NixOS is to have a fully reproducible system mounted on tmpfs where only user-defined files and directories are hooked into the temporary file system to be persistent (such as /home, /var/lib and some /etc files for instance). Why this is something achievable on NixOS, on OpenBSD side we are far from having the tooling to go that deep so I wrote home-impermanence that allows an user to just do that at their $HOME level.

What does it mean exactly? When you start your system, your $HOME directory will be mounted with an empty memory based file system (using mfs) and symbolic links to files and directories listed in the configuration file will be done in your $HOME. Every time you reboot, you will have the exact same set of files, extra files created meanwhile will be lost. When you hold a $HOME directory for long, you know you get many directories and files created in various ~/.config or ~/.local or directly as dotfiles in the top level of the home directory, with impermanence you can get ride of all the noise.

A benefit is that you can run software as if it was their first run, in some software upgrade you will avoid old settings that would create troubles, or settings that would disturb a whole class of applications (like a gtk setting affecting all gtk programs), with impermanence the user can decide exactly what should remain across reboots or disappear.

2. Implementation §

My implementation is a Perl script relying on some libraries packaged on OpenBSD, it will run as root from a rc service and the settings done in rc.conf.local. It will read the configuration file from the persistent directory holding the user data and create symlinks in the target directory to the files and directories, doing some sanitizing in the process to prevent listed files to be included in listed directories which would nest symlinks incorrectly.

I chose Perl because it's a stable language, OpenBSD ships with Perl and the very few dependencies required were already available in the ports tree.

The program could easily be ported to Linux, FreeBSD and maybe NetBSD, the mount_mfs calls could be replaced by a mount_tmpfs and the directories symlinks could be done with a mount_bind or mount_nullfs which we don't have on OpenBSD, if someone wants to port my project to another system I could help adding the required logic.

3. How to use §

I wrote a complete README file explaining the installation and configuration process, for full instructions refer to this document and the man page that ships with home-impermanence.

home-impermanence README

3.1. Installation §

Quick method:

git clone https://tildegit.org/solene/home-impermanence/
cd home-impermanence
doas make install
doas rcctl enable impermanence
doas rcctl set impermanence flags -u user -d /home/persist/
doas install -d /home/persist/

From now, you may want to make things quickly, logout from your user and run these commands, this will move your user directory and prepare the mountpoint.

mv /home/user /home/persist/user
install -d -o user -g wheel /home/user

Now, it's time to configure impermanence before running it.

3.2. Configuration §

Reusing the paths from the installation example, the configuration file should be in /home/persist/user/impermanence.yml , the file must be using YAML formatting. Here is my personal configuration file that you can use as a base.

size: 500m
files:
  - .Xdefaults
  - .Xresources
  - .bashrc
  - .gitconfig
  - .kshrc
  - .profile
  - .xsession
  - .tmux.conf
  - .config/kwalletrc
directories:
  - .claws-mail
  - .config/Thunar
  - .config/asciinema
  - .config/gajim
  - .config/kak
  - .config/keepassxc
  - .config/lagrange
  - .config/mpv
  - .config/musikcube
  - .config/openttd
  - .config/xfce4
  - .config/zim
  - .local/share/cozy
  - .local/share/gajim
  - .local/share/ibus-typing-booster
  - .local/share/kwalletd
  - .mozilla
  - .ssh
  - Documents
  - Downloads
  - Music
  - bin
  - dev
  - notes
  - tmp

When you think you are done, start the impermanence rc service with rcctl start impermanence and log-in. You should see all the symlinks you defined in your configuration file.

3.3. Result §

Here is the content of my $HOME directory when I use impermanence.

solene@daru ~> ls -la
total 104
drwxr-xr-x   8 solene  wheel    1024 Mar 15 12:10 .
drwxr-xr-x  17 root    wheel     512 Mar 14 15:36 ..
-rw-------   1 solene  wheel     165 Mar 15 09:08 .ICEauthority
-rw-------   1 solene  solene     53 Mar 15 09:08 .Xauthority
lrwxr-xr-x   1 root    wheel      34 Mar 15 09:08 .Xdefaults -> /home/permanent//solene/.Xdefaults
lrwxr-xr-x   1 root    wheel      35 Mar 15 09:08 .Xresources -> /home/permanent//solene/.Xresources
-rw-r--r--   1 solene  wheel      48 Mar 15 12:07 .aspell.en.prepl
-rw-r--r--   1 solene  wheel      42 Mar 15 12:07 .aspell.en.pws
lrwxr-xr-x   1 root    wheel      31 Mar 15 09:08 .bashrc -> /home/permanent//solene/.bashrc
drwxr-xr-x   9 solene  wheel     512 Mar 15 12:10 .cache
lrwxr-xr-x   1 root    wheel      35 Mar 15 09:08 .claws-mail -> /home/permanent//solene/.claws-mail
drwx------   8 solene  wheel     512 Mar 15 12:27 .config
drwx------   3 solene  wheel     512 Mar 15 09:08 .dbus
lrwxr-xr-x   1 root    wheel      34 Mar 15 09:08 .gitconfig -> /home/permanent//solene/.gitconfig
drwx------   3 solene  wheel     512 Mar 15 12:32 .gnupg
lrwxr-xr-x   1 root    wheel      30 Mar 15 09:08 .kshrc -> /home/permanent//solene/.kshrc
drwx------   3 solene  wheel     512 Mar 15 09:08 .local
lrwxr-xr-x   1 root    wheel      32 Mar 15 09:08 .mozilla -> /home/permanent//solene/.mozilla
lrwxr-xr-x   1 root    wheel      32 Mar 15 09:08 .profile -> /home/permanent//solene/.profile
lrwxr-xr-x   1 solene  wheel      30 Mar 15 12:10 .sbclrc -> /home/permanent/solene/.sbclrc
drwxr-xr-x   2 solene  wheel     512 Mar 15 09:08 .sndio
lrwxr-xr-x   1 root    wheel      28 Mar 15 09:08 .ssh -> /home/permanent//solene/.ssh
lrwxr-xr-x   1 root    wheel      34 Mar 15 09:08 .tmux.conf -> /home/permanent//solene/.tmux.conf
lrwxr-xr-x   1 root    wheel      33 Mar 15 09:08 .xsession -> /home/permanent//solene/.xsession
-rw-------   1 solene  wheel   25273 Mar 15 13:26 .xsession-errors
lrwxr-xr-x   1 root    wheel      33 Mar 15 09:08 Documents -> /home/permanent//solene/Documents
lrwxr-xr-x   1 root    wheel      33 Mar 15 09:08 Downloads -> /home/permanent//solene/Downloads
lrwxr-xr-x   1 root    wheel      30 Mar 15 09:08 HANGAR -> /home/permanent//solene/HANGAR
lrwxr-xr-x   1 root    wheel      27 Mar 15 09:08 dev -> /home/permanent//solene/dev
lrwxr-xr-x   1 root    wheel      29 Mar 15 09:08 notes -> /home/permanent//solene/notes
lrwxr-xr-x   1 root    wheel      33 Mar 15 09:08 quicklisp -> /home/permanent//solene/quicklisp
lrwxr-xr-x   1 root    wheel      27 Mar 15 09:08 tmp -> /home/permanent//solene/tmp

3.4. Rollback §

If you want to rollback it's easy, disable impermanence, move /home/persist/user to /home/user and you are done.

4. Conclusion §

I really don't want to go back to not using impermanence since I tried it on NixOS. I thought implementing it only for $HOME would be good enough as a start and started thinking about it, made a proof of concept to see if the symbolic links method was enough to make it work, and it was!

I hope you will enjoy this as much as I do, feel free to contact me if you need some help understanding the setup.

Reed-alert: five years later

Written by Solène, on 10 February 2022.
Tags: #unix #reed-alert #linux #lisp #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

I wrote the program reed-alert five years ago, I've been using it since its first days, here is some feed back about it.

The software reed-alert is meant to be used by system administrators who want to monitor their infrastructures and get alerts when things go wrong. I got a lot more experience in the monitoring field over time and I wanted to share some thoughts about this project.

reed-alert source code

2. Reed-alert §

2.1. The name §

The software name is a pun I found in a Star Trek Enterprise episode.

Reed alert pun origins

2.2. Project finished §

The code didn't receive many commits over the last years, I consider the program to be complete with regard to features, but new probes could be added, or bug fixes could be done. But the core of the software itself is perfect to me.

The probes are small parts of code allowing to monitor extra states, like http return code, working ping, service started etc... It's already easy to extend reed-alert using a shell command returning 0 or not 0 to define a custom probe.

2.3. Reliability §

I don't remember having a single issue with reed-alert since I've set it up on my server. It's run by a cron job every 10 minutes, this mean a common lisp interpreter is loading the code, evaluating the configuration file, running the check commands and alerts commands if required, and stops. I chose a serviceless paradigm for reed-alert as it make the code and usage a lot simpler. With a running service, it could fail, leak memory, be exploited and certainly many other bugs I can't think of.

Reed-alert is simple as it only need a common lisp interpreter, the most notable sbcl and ecl interpreters are absolutely reliable and change very little over time. Some unix standard commands are required for some checks or default alerts, such as ping, service, mail or curl but this defers all the work to well established binaries.

The source code is minimal with 179 lines for reed-alert core and 159 lines for the probes, a total of 338 lines of code (including empty lines and comments), hacking on reed-alert is super easy and always a lot of fun for me. For whatever reason, my common lisp software often work at first try when I add new features, so it's always pleasant to work on them.

2.4. Awesome features §

One aspect of reed-alert that may disturb users at first is the choice of common lisp code as a configuration file, this may look complicated at first, but a simple configuration doesn't require more common lisp knowledge than what is explained in reed-alert documentation. But it gives all its power when you need to loop over a data entry to run checks, allowing to make reed-alert dynamic instead of handwriting all the configuration.

The use of common lisp as configuration has other advantages, it's possible to chain checks to easily prevent some checks to be done in case a condition is failing. Let me give a few examples for this:

  • if you monitor a web server, you first want to check if it replies on ICMP before trying to check and report errors on HTTP level
  • if you monitor remote servers, you first want to check if you can reach the internet and that your local gateway is online
  • if you check a local web server, it would be a good idea to check if all the required services are running first

All the previous conditions can be done with reed-alert thanks to the code-as-configuration choice.

2.5. Scalability §

I've been asked a few times if reed-alert could be used in a professional context. Depending on what you call a professional environment, I will reply it depends.

Reed-alert is dumb, it needs to be run from a scheduling software (such as cron) and will sequentially run the checks. It won't guarantee a perfect timing between checks.

If you need multiples machines to run a set of checks, reed-alert is not able to share the states to continue to work reliably in a high availability environment.

In regard to resources usage, while reed-alert is small it needs to run the command lisp interpreter every time, if you want to run reed-alert every minute or multiple time per minute, I'd recommend using something else.

3. A real life example §

Here is a chunk of the configuration I've been running for years, it checks the system itself and some remote servers.

(=> mail disk-usage  :path "/"     :limit 60 :desc "partition /")
(=> mail disk-usage  :path "/var"  :limit 70 :desc "partition /var")
(=> mail disk-usage  :path "/home" :limit 95 :desc "partition /home")
(=> mail service :name "dovecot")
(=> mail service :name "spamd")
(=> mail service :name "dkimproxy_out")
(=> mail service :name "smtpd")
(=> mail service :name "ntpd")

(=> mail number-of-processes :limit 140)

;; check dataswamp server is working
(=> mail ping :host "dataswamp.org" :desc "Dataswamp")

;; check webzine related web servers
(and
    (=> mail ping :host "openports.pl"     :desc "Liaison Grifon.fr")
    (=> mail curl-http-status :url "https://webzine.puffy.cafe" :desc "Webzine Puffy.cafe" :timeout 10)
    (=> mail curl-http-status :url "https://puffy.cafe" :desc "Puffy.cafe" :timeout 10)
    (=> mail ssl-expiration :host "webzine.puffy.cafe" :seconds (* 7 24 60 60))
    (=> mail ssl-expiration :host "puffy.cafe" :seconds (* 7 24 60 60)))

;; check openports.pl is working
(and
    (=> mail ping :host "46.23.90.152"  :desc "Openports.pl ping")
    (=> mail curl-http-status :url "http://46.23.90.152" :desc "Packages OpenBSD http" :timeout 10))

;; check www.openbsd.org website is replying under 10 seconds
(=> mail curl-http-status :url "https://www.openbsd.org" :desc "OpenBSD.org" :timeout 10)

;; check if a XML file is created regularly and valid
(=> mail file-updated :path "/var/www/htdocs/solene/openbsd-current.xml" :limit 1440)
(=> mail command :command (format nil "xmllint /var/www/htdocs/solene/openbsd-current.xml") :desc "XML openbsd-current.xml is not valid")


;; monitoring multiple gopher servers
(loop for host in '("grifon.fr" "dataswamp.org" "gopherproject.org")
      do
      (=> mail command
          :try 6
          :command (format nil "echo '/is-alive?done-by-solene-at-libera' | nc -w 3 ~a 70" host)
          :desc (concatenate 'string "Gopher " host)))

(quit)

4. Conclusion §

I wrote a simple software using an old programming language (Common LISP ANSI is from 1994), the result is that it's reliable over time, require no code maintenance and is fun to code on.

Common Lisp on Wikipedia

Harden your NixOS workstation

Written by Solène, on 13 January 2022.
Tags: #nix #nixos #security

Comments on Fediverse/Mastodon

1. Introduction §

Coming from an OpenBSD background, I wanted to harden my NixOS system for better security. As you may know (or not), security mitigations must be thought against a security threat model. My model here is to prevent web browsers to leak data, prevent services to be exploitable remotely and prevent programs from being exploited to run malicious code.

NixOS comes with a few settings to improve in these areas, I'll share a sample of configuration to increase the default security. Unrelated to security defense itself, but you should absolutely encrypt your filesystem, so in case of physical access to your computer no data could be extracted.

2. Use the hardened profile §

There are a few profiles available by default in NixOS which are files with a set of definitions and one of them is named "hardened" because it enables many security measures.

Link to the hardened profile definition

Here is a simplified list of important changes:

  • use the hardened Linux kernel (different defaults and some extra patches from https://github.com/anthraxx/linux-hardened/)
  • use the memory allocator "scudo", protecting against some buffer overflow exploits
  • prevent kernel modules to be loaded after boot
  • protect against rewriting kernel image
  • increase containers/virtualization protection at a performance cost (L1 flush or page table isolation)
  • apparmor is enabled by default
  • many filesystem modules are forbidden because old/rare/not audited enough
  • many other specific tweaks

Of course, using this mode will slightly reduce the system performance and may trigger some runtime problems due to the memory management being less permissive. On one hand, it's good because it allows to catch programming errors, but on the other hand it's not fun to have your programs crashing when you need them.

With the scudo memory allocator, I have troubles running Firefox, it will only start after 2 or 3 crashes and then will work fine. There is a less permissive allocator named graphene-hardened, but I had too much troubles running programs with it.

3. Use firewall §

One simple rule is to block any incoming traffic that would connect to listening services. It's way more secure to block everything and then allow the services you know must be open to the outside than relying on the service's configuration to not listen on public interfaces.

4. Use Clamav §

Clamav is an antivirus, and yes it can be useful on Linux. If it can prevent you at least once to run a hostile binary, then it's worth running it.

5. Firejail §

I featured firejail previously on my blog, I'm convinced of its usefulnes. You can run a program using firejail, and it will restrict its permissions and rights so in case of security breach, the program will be restricted.

This is rather important to run web browsers with it because it will prevent them any access to the filesystem except ~/Downloads/ and a few required directories (local profile, /etc/resolv.conf, font cache etc...).

6. Enable this on NixOS §

Because NixOS is declarative, it's easy to share the configuration. My configuration supports both Firefox and Chromium, you can remove the related lines you don't need.

Be careful about the import declaration, you certainly already have one for the ./hardware-configuration.nix file.

 imports =
   [
      ./hardware-configuration.nix
      <nixpkgs/nixos/modules/profiles/hardened.nix>
   ];

  # enable firewall and block all ports
  networking.firewall.enable = true;
  networking.firewall.allowedTCPPorts = [];
  networking.firewall.allowedUDPPorts = [];

  # disable coredump that could be exploited later
  # and also slow down the system when something crash
  systemd.coredump.enable = false;

  # required to run chromium
  security.chromiumSuidSandbox.enable = true;

  # enable firejail
  programs.firejail.enable = true;

  # create system-wide executables firefox and chromium
  # that will wrap the real binaries so everything
  # work out of the box.
  programs.firejail.wrappedBinaries = {
      firefox = {
          executable = "${pkgs.lib.getBin pkgs.firefox}/bin/firefox";
          profile = "${pkgs.firejail}/etc/firejail/firefox.profile";
      };
      chromium = {
          executable = "${pkgs.lib.getBin pkgs.chromium}/bin/chromium";
          profile = "${pkgs.firejail}/etc/firejail/chromium.profile";
      };
  };

  # enable antivirus clamav and
  # keep the signatures' database updated
  services.clamav.daemon.enable = true;
  services.clamav.updater.enable = true;

Rebuild the system, reboot and enjoy your new secure system.

7. Going further: network filtering §

If you want to absolutely control your network connections, I'd absolutely recommend the service OpenSnitch. This is a daemon that will listen to all the network done on the system and allow you to allow/block connections per executable/source/destination/protocol/many parameters.

OpenSnitch comes with a GUI app called opensnitch-ui which is mandatory, if the ui is not running, no filtering is done. When the ui is running, every time a new connection is not matching an existing rule, you will be prompted with information telling you what executable is trying to do on which protocol with which host, then you can decide how long you allow this (or block).

Just use services.opensnitch.enable = true; in the system configuration and run opensnitch-ui program in your graphical session. To have persistent rules, open opensnitch-ui, go in the Preferences menu and tab Database, choose "Database type: File" and pick a path to save it (it's a sqlite database).

From this point, you will have to allow / block all network done on your system, it can be time-consuming at first, but it's user-friendly enough and rules can be done like "allow this entire executable" so you don't have to allow every website visited by your web browser (but you could!). You may be surprised by the amount of traffic done by non networking programs. After some time, the rule set should be able to cope with most of your needs without needing to add new entries.

OpenSnitch wiki: getting started

How to pin a nix-shell environment using niv

Written by Solène, on 12 January 2022.
Tags: #nix #nixos #shell

Comments on Fediverse/Mastodon

1. Introduction §

In the past I shared a bit about Nix nix-shell tool, allowing to have a "temporary" environment with a specific set of tools available. I'm using it on my blog to get all the dependencies required to rebuild it without having to remember what programs to install.

But while this method was practical, as I'm running NixOS development version (called unstable channel), I have to download the new versions of the dependencies every time I use the nix shell. This is long on my DSL line, and also a waste of bandwidth.

There is a way to pin the version of the packages, so I always use the exact same environment, whatever the version of my nix.

2. Use niv tool §

Let's introduce you to niv, a program to manage nix dependencies, for this how-to I will only use a fraction of its features. We just want it to init a directory with a default configuration pinning the nixpkgs repository to a branch / commit ID, and we will tell the shell to use this version.

niv project GitHub homepage

Let's start by running niv (you can get niv from nix package manager) in your directory:

niv init

It will create a nix/ directory with two files: sources.json and sources.nix, looking at the content is not fascinating here (you can take a look if you are curious though). The default is to use the latest nixpkgs release.

3. Create a shell.nix file §

My previous shell.nix file looked like this:

with (import <nixpkgs> {});
mkShell {
    buildInputs = [
        gnumake sbcl multimarkdown python3Full emacs-nox toot nawk mandoc libxml2
    ];
}

Yes, I need all of this for my blog to work because I have texts in org-mode/markdown/mandoc/gemtext/custom. The blog also requires toot (for mastodon), sbcl (for the generator), make (for building and publishing).

Now, I will make a few changes to use the nix/sources.nix file to tell it where to get the nixpkgs information, instead of which is the system global.

let
  sources = import ./nix/sources.nix;
  pkgs = import sources.nixpkgs {};
in
with pkgs;
pkgs.mkShell {
    buildInputs = [
        gnumake sbcl multimarkdown python3Full emacs-nox
        toot nawk mandoc libxml2
    ];
}

That's all! Now, when I run nix-shell in the directory, I always get the exact same shell and set of packages every day.

4. How to update? §

Because it's important to update from time to time, you can easily manage this using niv, it will bump the latest commit id of the branch of the nixpkgs repository:

niv update nixpkgs -b master

When a new release is out, you can switch to the new branch using:

niv modify nixpkgs -a branch=release-21.11

5. Using niv with configuration.nix §

It's possible to use niv to pin the git revision you want to use to build your system, it's very practical for many reasons like following the development version on multiple machines with the exact same revision. The snippet to use sources.nix for rebuilding the system is a bit different.

Replace "{ pkgs, config, ... }:" with:

{
  sources ? import ./nix/sources.nix,
  pkgs ? import sources.nixpkgs {},
  config, ...
}:

Of course, you need to run "niv init" in /etc/nixos/ before if you want to manage your system with niv.

6. Extra tip: automatically run nix-shell with direnv §

It's particularly comfortable to have your shell to automatically load the environment when you cd into a project requiring a nix-shell, this is doable with the direnv program.

nixos documentation about direnv usage

direnv project homepage

This can be done in 3 steps after you installed direnv in your profile:

  1. create a file .envrc in the directory with the content "use nix" (without double quotes of course)
  2. execute "direnv allow"
  3. create the hook in your shell, so it knows how to do with direnv (do this only once)

How to hook direnv in your shell

Everytime you will cd into the directory, nix-shell will be automatically started.

My plans for 2022

Written by Solène, on 08 January 2022.
Tags: #life #blog

Comments on Fediverse/Mastodon

Greetings dear readers, I wish you a happy new year and all the best. Like I did previously at the new year time, although it's not a yearly exercise, I would like to talk about the blog and my plan for the next twelve months.

1. About me §

Let's talk about me first, it will make sense for the blog part after. I plan to find a new job, maybe switch into the cybersecurity field or work in some position allowing me to contribute to an open source project, it's not that easy to find, but I have hope.

This year, I will work at getting new skills, this should help me find jobs, but I also think I've been a resting a bit about learning over the last two years. My plan is to dedicate 45 minutes every day to learn about a topic. I already started doing so with some security and D language readings.

2. About the blog §

With regular learning time, I'm not sure yet if I will have much desire to write here as often as I did in 2021. I'm absolutely sure the publication rate will drop, but I will try to maintain a minimum, because I'm learning I will want to share some ideas, experiences or knowledge hopefuly.

I'm thanksful to readers community I have, I often get feedback by email or IRC or mastodon about my posts, so I can fix them, extend them or rework them if I was wrong. This is invaluable to me, it helps me to make connections to other people, and it's what make life interesting.

3. Podcast §

In December 2021, I had the chance to be interviewed by the people of the BSDNow podcast, I'm talking about how I got into open source, about my blog but also about the old laptop challenge I made last year.

Access to the podcast link on BSDNow

Thanks everyone! Let's have fun with computers!

My NixOS configuration

Written by Solène, on 21 December 2021.
Tags: #nixos #linux

Comments on Fediverse/Mastodon

1. Introduction §

Let me share my NixOS configuration file, the one in /etc/nixos/configuration.nix that describe what is installed on my Lenovo T470 laptop.

The base of NixOS is that you declare every user, services, network and system settings in a file, and finally it configures itself to match your expectations. You can also install global packages and per-user packages. It makes a system environment reproducible and reliable.

2. The file §

{ config, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  # run garbage collector at 19h00 everyday
  # and remove stuff older than 60 days
  nix.gc.automatic = true;
  nix.gc.dates = "19:00";
  nix.gc.persistent = true;
  nix.gc.options = "--delete-older-than 60d";

  # clean /tmp at boot
  boot.cleanTmpDir = true;

  # latest kernel
  boot.kernelPackages = pkgs.linuxPackages_latest;

  # sync disk when buffer reach 6% of memory
  boot.kernel.sysctl = {
      "vm.dirty_ratio" = 6;
  };

  # allow non free stuff
  nixpkgs.config.allowUnfree = true;

  # Use the systemd-boot EFI boot loader.
  boot.loader.systemd-boot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;

  networking.hostName = "t470";
  time.timeZone = "Europe/Paris";
  networking.networkmanager.enable = true;

  # wireguard VPN
  networking.wireguard.interfaces = {
      wg0 = {
              ips = [ "192.168.5.1/24" ];
              listenPort = 1234;
              privateKeyFile = "/root/wg-private";
              peers = [
              { # server
               publicKey = "MY PUB KEY";
               endpoint = "SERVER:PORT";
               allowedIPs = [ "192.168.5.0/24" ];
              }];
      };
  };

  # firejail firefox by default
  programs.firejail.wrappedBinaries = {
      firefox = {
          executable = "${pkgs.lib.getBin pkgs.firefox}/bin/firefox";
          profile = "${pkgs.firejail}/etc/firejail/firefox.profile";
      };
  };


  # azerty keyboard <3
  i18n.defaultLocale = "fr_FR.UTF-8";
  console = {
  #   font = "Lat2-Terminus16";
    keyMap = "fr";
  };

  # clean logs older than 2d
  services.cron.systemCronJobs = [
      "0 20 * * * root journalctl --vacuum-time=2d"
  ];

  # nvidia prime offload rendering for eGPU
  hardware.nvidia.modesetting.enable = true;
  hardware.nvidia.prime.sync.allowExternalGpu = true;
  hardware.nvidia.prime.offload.enable = true;
  hardware.nvidia.prime.nvidiaBusId = "PCI:10:0:0";
  hardware.nvidia.prime.intelBusId = "PCI:0:2:0";
  services.xserver.videoDrivers = ["nvidia" ];

  # programs
  programs.steam.enable = true;
  programs.firejail.enable = true;
  programs.fish.enable = true;
  programs.gamemode.enable = true;
  programs.ssh.startAgent = true;

  # services
  services.acpid.enable = true;
  services.thermald.enable = true;
  services.fwupd.enable = true;
  services.vnstat.enable = true;

  # Enable the X11 windowing system.
  services.xserver.enable = true;
  services.xserver.displayManager.sddm.enable = true;
  services.xserver.desktopManager.plasma5.enable = true;
  services.xserver.desktopManager.xfce.enable = false;
  services.xserver.desktopManager.gnome.enable = false;

  # Configure keymap in X11
  services.xserver.layout = "fr";
  services.xserver.xkbOptions = "eurosign:e";

  # Enable sound.
  sound.enable = true;
  hardware.pulseaudio.enable = true;

  # Enable touchpad support
  services.xserver.libinput.enable = true;

  users.users.solene = {
     isNormalUser = true;
     shell = pkgs.fish;
     packages = with pkgs; [
        gajim audacity chromium dmd dtools
     	kate kdeltachat pavucontrol rclone rclone-browser
     	zim claws-mail mpv musikcube git-annex
     ];
     extraGroups = [ "wheel" "sudo" "networkmanager" ];
  };

  # my gaming users running steam/lutris/emulators
  users.users.gaming = {
     isNormalUser = true;
     shell = pkgs.fish;
     extraGroups = [ "networkmanager" "video" ];
     packages = with pkgs; [ lutris firefox ];
  };

  users.users.aria = {
     isNormalUser = true;
     shell = pkgs.fish;
     packages = with pkgs; [ aria2 ];
  };

  # global packages
  environment.systemPackages = with pkgs; [
      ncdu kakoune git rsync restic tmux fzf
  ];

  # Enable the OpenSSH daemon.
  services.openssh.enable = true;

  # Open ports in the firewall.
  networking.firewall.enable = true;
  networking.firewall.allowedTCPPorts = [ 22 ];
  networking.firewall.allowedUDPPorts = [ ];

  # user aria can only use tun0
  networking.firewall.extraCommands = "
iptables -A OUTPUT -o lo -m owner --uid-owner 1002 -j ACCEPT
iptables -A OUTPUT -o tun0 -m owner --uid-owner 1002 -j ACCEPT
iptables -A OUTPUT -m owner --uid-owner 1002 -j REJECT
  ";

  # This value determines the NixOS release from which the default
  # settings for stateful data, like file locations and database versions
  # on your system were taken. It‘s perfectly fine and recommended to leave
  # this value at the release version of the first install of this system.
  # Before changing this value read the documentation for this option
  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
  system.stateVersion = "21.11"; # Did you read the comment?

}

Restrict users to a network interface on Linux

Written by Solène, on 20 December 2021.
Tags: #linux #networking #security #privacy

Comments on Fediverse/Mastodon

1. Introduction §

If for some reasons you want to prevent a system user to use network interfaces except one, it's doable with a couple of iptables commands.

The use case would be to force your user to go through a VPN and make sure it can't reach the Internet if the VPN is not available.

iptables man page

2. Iptables §

We can use simple rules using the "owner" module, basically, we will allow traffic through tun0 interface (the VPN) for the user, and reject traffic for any other interface.

Iptables is applying first matching rule, so if traffic is going through tun0, it's allowed and otherwise rejected. This is quite simple and reliable.

We will need the user id (uid) of the user we want to restrict, this can be found as third field of /etc/passwd or by running "id the_user".

iptables -A OUTPUT -o lo -m owner --uid-owner 1002 -j ACCEPT
iptables -A OUTPUT -o tun0 -m owner --uid-owner 1002 -j ACCEPT
iptables -A OUTPUT -m owner --uid-owner 1002 -j REJECT

Note that instead of --uid-owner it's possible to use --gid-owner with a group ID if you want to make this rule for a whole group.

To make the rules persistent across reboots, please check your Linux distribution documentation.

3. Going further §

I trust firewall rules to do what we expect from them. Some userland programs may be able to restrict the traffic, but we can't know for sure if it's truly blocking or not. With iptables, once you made sure the rules are persistent, you have a guarantee that the traffic will be blocked.

There may be better ways to achieve the same restrictions, if you know one that is NOT complex, please share!

Playing video games on Linux

Written by Solène, on 19 December 2021.
Tags: #linux #gaming

Comments on Fediverse/Mastodon

1. Introduction §

While I mostly make posts about playing on OpenBSD, I also do play video games on Linux. There is a lot more choice, but it comes with the price that the choice comes from various sources with pros and cons.

2. Commercial stores §

There are a few websites where you can get games:

2.1. itch.io §

Itch.io is dedicated to indie games, you can find many games running on Linux, most games there are free. Most games could be considered "amateurish" but it's a nice pool from which some gems get out like Celeste, Among Us or Noita.

itch.io website

2.2. Steam §

It is certainly the biggest commercial platform, it requires the steam desktop Client and an account to be useful. You can find many free-to-play video games, (including some open source games like OpenTTD or Wesnoth who are now available on Steam for free) but also paid games. Steam is working hard on their tool to make Windows games running on Linux (based on Wine + many improvements on the graphic stack). The library manager allows Linux games filtering if you want to search native games. Steam is really a big DRM platform, but it also works well.

Steam website

2.3. GOG §

GOG is a webstore selling video games (many old games from people's childhood but not only), they only require you to have an account. When you buy a game in their store, you have to download the installer, so you can keep/save it, without any DRM beyond the account registration on their website to buy games.

GOG website

2.4. Your packager manager / flatpak §

There are many open source video games around, they may be available in your package manager, allowing a painless installation and maintenance.

Flatpak package manager also provides video games, some are recent and complex games that are not found in many package managers because of the huge work required.

flathub flatpak repository, games page

2.5. Developer's website §

Sometimes, when you want to buy a game, you can buy it directly on the developer's website, it usually comes without any DRM and doesn't rely on a third party vendor. I know I did it for Rimworld, but some other developers offer this "service", it's quite rare though.

2.6. Epic game store §

They do not care about Linux.

3. Streaming services §

It's now possible to play remotely through "cloud computing", using a company's computer with a good graphic card. There are solutions like Nvidia with Geforce Now or Stadia from Google, both should work in a web browser like Chromium.

They require a very decent Internet access with at least 15 MB/s of download speed for a 1080p stream but will work almost anywhere.

4. How to manage games §

Let me describe a few programs that can be used to manage games libraries.

4.1. Steam §

As said earlier, Steam has its own mandatory desktop client to buy/install/manage games.

4.2. Lutris §

Lutris is an ambitious open source project, it aims to be a game library manager allowing to mix any kind of game: emulation / Steam / GOG / Itch.io / Epic game Store (through Wine) / Native linux games etc...

Its website is a place where people can send recipes for installing some games that could be complicated, allowing to automate and distribute in the community ways to install some games. But it makes very easy to install games from GOG. There is a recent feature to handle the Epic game store, but it's currently not really enjoyable and the launcher itself running through wine draw for CPU like madness.

It has nice features such as activating a HUD for displaying FPS, automatically run "gamemode" (disabling screen effects, doing some optimization), easy offloading rendering to graphic card, set locale or switch to qwerty per game etc...

It's really a nice project that I follow closely, it's very useful as a Linux gamer.

lutris project website

4.3. Minigalaxy §

Minigalaxy is a GUI to manage GOG games, installing them locally with one click, keeping them updated or installing DLC with one click too. It's really simplistic compared to Lutris, but it's made as a simple client to manage GOG games which is perfectly fine.

Minigalaxy can update games while Lutris can't, both can be used on the same installed video games. I find these two are complementary.

Minigalaxy project website

4.4. play.it §

This tool is a set of script to help you install native Linux video games in your system, depending on their running method (open source engine, installer, emulator etc...).

play.it official website

5. Conclusion §

It has never been so easy to play video games on Linux. Of course, you have to decide if you want to run closed sources programs or not. Even if some games are closed sources, some fans may have developed a compatible open source engine from scratch to play it again natively given you have access to the "assets" (sets of files required for the game which are not part of the engine, like textures, sounds, databases).

List of game engine recreation (Wikipedia EN)

OpenVPN on OpenBSD in its own rdomain to prevent data leak

Written by Solène, on 16 December 2021.
Tags: #openbsd #openvpn #security

Comments on Fediverse/Mastodon

1. Introduction §

Today I will explain how to establish an OpenVPN tunnel through a dedicated rdomain to only expose the VPN tunnel as an available interface, preventing data leak outside the VPN (and may induce privacy issues). I did the same recently for WireGuard tunnels, but it had an integrated mechanism for this.

Let's reuse the network diagram from the WireGuard text to explain:


    +-------------+
    |   server    | tun0 remote peer
    |             |---------------+
    +-------------+               |
           | public IP            |
           | 1.2.3.4              |
           |                      |
           |                      |
    /\/\/\/\/\/\/\                |OpenVPN
    |  internet  |                |VPN
    \/\/\/\/\/\/\/                |
           |                      |
           |                      |
           |rdomain 1             |
    +-------------+               |
    |   computer  |---------------+
    +-------------+ tun0
                    rdomain 0 (default)

We have our computer and have been provided an OpenVPN configuration file, we want to establish the OpenVPN toward the server 1.2.3.4 using rdomain 1. We will set our network interfaces into rdomain 1 so when the VPN is NOT up, we won't be able to connect to the Internet (without the VPN).

2. Network configuration §

Add "rdomain 1" to your network interfaces configuration file like "/etc/hostname.trunk0" if you use a trunk interface to aggregate Ethernet/Wi-Fi interfaces into an automatic fail over trunk, or in each interface you are supposed to use regularly. I suppose this setup is mostly interesting for wireless users.

Create a "/etc/hostname.tun0" file that will be used to prepare the tun0 interface for OpenVPN, add "rdomain 0" to the file, this will be enough to create the tun0 interface at startup. (Note that the keyword "up" would work too, but if you edit your files I find it easier to understand the rdomains of each interface).

Run "sh /etc/netstart" as root to apply changes done to the files, you should have your network interfaces in rdomain 1 now.

3. OpenVPN configuration §

From here, I assume your OpenVPN configuration works. The OpenVPN client/server setup is out of the scope of this text.

We will use rcctl to ensure openvpn service is enabled (if it's already enabled this is not an issue), then we will configure it to use rtable 1 to run, this mean it will connect through the interfaces in the rdomain 1.

If your OpenVPN configuration runs a script to set up the route(s) (through "up /etc/something..." directive in the configuration file), you will have to by add parameter -T0 to the command route in the script. This is important because openvpn will run in rdomain 1 so calls to "route" will apply to routing table 1, so you must change the route command to apply the changes in routing table 0.

rcctl enable openvpn
rcctl set openvpn rtable 1
rcctl restart openvpn

Now, you should have your tun0 interface in rdomain 0, being the default route and the other interfaces in rdomain 1.

If you run any network program it will go through the VPN, if the VPN is down, the programs won't connect to the Internet (which is the wanted behavior here).

4. Conclusion §

The rdomain and routing tables concepts are powerful tools, but they are not always easy to grasp, especially in a context of a VPN mixing both (one for connectivity and one for the tunnel). People using VPN certainly want to prevent their programs to not go through the VPN and this setup is absolutely effective in that task.

Persistency management of memory based filesystem on OpenBSD

Written by Solène, on 15 December 2021.
Tags: #openbsd #performance #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

For saving my SSD and also speeding up my system, I store some cache files into memory using the mfs filesystem on OpenBSD. But that would be nice to save the content upon shutdown and restore it at start, wouldn't it?

I found that storing the web browser cache in a memory filesystem drastically improve its responsiveness, but it's hard to make measurements of it.

Let's do that with a simple rc.d script.

2. Configuration §

First, I use a mfs filesystem for my Firefox cache, here is the line in /etc/fstab

/dev/sd3b	   /home/solene/.cache/mozilla mfs rw,-s400M,noatime,nosuid,nodev 1 0

This mean I have a 400 MB partition using system memory, it's super fast but limited. tmpfs is disabled in the default kernel because it may have issues and is not well enough maintained, so I stick with mfs which is available out of the box. (tmpfs is faster and only use memory when storing file, while mfs reserves the memory chunk at first).

3. The script §

We will write /etc/rc.d/persistency with the following content, this is a simple script that will store as a tgz file under /var/persistency every mfs mountpoint found in /etc/fstab when it receives the "stop" command. It will also restore the files at the right place when receiving the "start" command.

#!/bin/ksh

STORAGE=/var/persistency/

if [[ "$1" == "start" ]]
then
    install -d -m 700 $STORAGE
    for mountpoint in $(awk '/ mfs / { print $2 }' /etc/fstab)
    do
        tar_name="$(echo ${mountpoint#/} | sed 's,/,_,g').tgz"
        tar_path="${STORAGE}/${tar_name}"
        test -f ${tar_path}
        if [ $? -eq 0 ]
        then
            cd $mountpoint
            if [ $? -eq 0 ]
            then
                tar xzfp ${tar_path} && rm ${tar_path}
            fi
        fi
    done
fi

if [[ "$1" == "stop" ]]
then
    install -d -m 700 $STORAGE
    for mountpoint in $(awk '/ mfs / { print $2 }' /etc/fstab)
    do
        tar_name="$(echo ${mountpoint#/} | sed 's,/,_,g').tgz"
        cd $mountpoint
        if [ $? -eq 0 ]
        then
            tar czf ${STORAGE}/${tar_name} .
        fi
    done
fi

All we need to do now is to use "rcctl enable persistency" so it will be run with start/stop at boot/shutdown times.

4. Conclusion §

Now I'll be able to carry my Firefox cache across reboots while keeping it in mfs.

  • Beware! A situation like using a mfs for a cache can lead to getting a full filesystem because it's never emptied, I think I'll run into the mfs filesystem full after a week or two.
  • Beware 2! If the system has a crash, mfs data will be lost. The script remove the archives at boot after using it, you could change the script to remove them before creating the newer archive upon stop, so at least you could recover "latest known version", but it's absolutely not a backup. mfs data are volatile and I just want to save it softly for performance purpose.

What are the VPN available on OpenBSD

Written by Solène, on 11 December 2021.
Tags: #openbsd #vpn #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to write this text for some time, a list of VPN with encryption that can be used on OpenBSD. I really don't plan to write about all of them but I thought it was important to show the choices available when you want to create a VPN between two peers/sites.

2. VPN §

VPN is an acronym for Virtual Private Network, is the concept of creating a network relying on a virtual layer like IP to connect computers, while regular network use physical network layer like Ethernet cable, wifi or light.

There are different VPN implementation existing, some are old, some are new. They have pros and cons because they were done for various purpose. This is a list of VPN protocols supported by OpenBSD (using base or packages).

2.1. OpenVPN §

Certainly the most known, it's free and open source and is widespread.

Pros:

  • works with tun or tap interfaces. tun device is a virtual network interface using IP while tap device is a virtual network interface passing Ethernet and which can be used to interconnect Ethernet networks across internet (allowing remote dhcp or device discovery)
  • secure because it uses SSL, if the SSL lib is trusted then OpenVPN can be trusted
  • can work with TCP or UDP, this allow setups such as using TCP/443 or UDP/53 to try to bypass local restrictions
  • flexible in regards to version difference allowed between client and server, it's rare to have an incompatible client

Cons:

  • certificate management isn't straightforward for the initial setup

2.2. WireGuard §

A recent VPN protocol joined the party with an interesting approach. It's supported by OpenBSD base system using ifconfig.

Pros:

  • connection is stateless, so if your IP change (when switching network for example) or you experience network loss, you don't need to renegotiate the connection every time this happen, making the connection really resilient.
  • setup is easy because it only require exchanging public keys between clients

Cons:

  • the crypto choice is very limited and in case of evolution older clients may have issue to connect (this is a cons as deployment but may be considered a good thing for security)

OpenBSD ifconfig man page anchored to WireGuard section

Examples of wg interfaces setup

2.3. SSH §

SSH is known for being a secure way to access a remote shell but it can also be used to create a VPN with a tun interface. This is not the best VPN solution available but at least it doesn't require much software and could be enough for some users.

Pros:

  • everyone has ssh

Cons:

  • performance are not great
  • documentation about the -w flag used for creating a VPN may be sparse for many

2.4. mlvpn §

mlvpn is a software to aggregate links through VPN technology

Pros:

  • it's a simple way to aggregate links client side and NAT from the server

Cons:

  • it partly obsolete due to MPTCP protocol doing the same but a lot better (but OpenBSD doesn't do MPTCP)
  • it doesn't work very well when using different kind of internet links (DSL/4G/fiber/modem)

2.5. IPsec §

IPSec is handled with iked in base system or using strongswan from ports. This is the most used VPN protocol, it's reliable.

Pros:

  • most network equipment know how to do IPsec
  • it works

Cons:

  • it's often complicated to debug
  • older compatibility often means you have to downgrade security to make the VPN work instead of saying it's not possible and ask the other peer to upgrade

OpenBSD FAQ about VPN

2.6. Tinc §

Meshed VPN that works without a central server, this is meant to be robust and reliable even if some peers are down.

Pros:

  • allow clients to communicate between themselves

Cons:

  • it doesn't use a standardized protocol (it's not THAT bad)

Note that Tailscale is a solution to create something similar using WireGuard.

2.7. Dsvpn §

Pros:

  • works on TCP so it's easier to bypass filtering
  • easy to setup

Cons:

  • small and recent project, one could say it has less "eyes" reading the code so security may be hazardous (the crypto should be fine because it use common crypto)

2.8. Openconnect §

I never heard of it before, I found it in the ports tree while writing this text. There is openconnect package to act as a client and ocserv to act as a server.

Pros:

  • it can use TCP to try to bypass filtering through TCP/443 but can fallback to UDP for best performance

Cons:

  • the open source implementation (server) seems minimalist

2.9. gre §

gre is a special device on OpenBSD to create VPN without encryption, it's recommended to use it over IPSec. I don't cover it more because I was emphasing on VPN with encryption.

gre interface man page

3. Conclusion §

If you never used a VPN, I'd say OpenVPN is a good choice, it's versatile and it can easily bypass restrictions if you run it on port TCP/443.

I personnaly use WireGuard on my phone to reach my emails, because of WireGuard stateless protocol the VPN doesn't draw battery to maintain the connection and doesn't have to renogicate every time the phone gets Internet access.

Port of the week: cozy

Written by Solène, on 09 December 2021.
Tags: #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

The Port of the week of this end of 2021 is Cozy a GTK audio book player. There are currently not much alternative outside of audio players if you want to listen to audio books.

Cozy project website

2. How to install §

On OpenBSD I imported cozy in December 2021 so it will be available from OpenBSD 7.1 or now in -current, a simple "pkg_add cozy" is required to install.

On Linux, there is a flatpak package if your distribution doesn't provide a package.

3. Features §

Cozy provides a few features making it more interesting than a regular music player:

  • keep track of your advancement of each book
  • playback speed can be changed if you want to listen faster (or slower)
  • automatic rewind can be configured when you resume playing, it's useful when you need to pause when disturbed and you want to resume the playback
  • sleep timer if you want playback to stop after some time
  • the UI is easy to use and nice
  • can make local copies of audio books from remote sources
Screenshot of Cozy ready to play an audio book
Screenshot of Cozy ready to play an audio book

Nvidia card in eGPU and NixOS

Written by Solène, on 05 December 2021.
Tags: #linux #games #nixos #egpu

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1. Updates §

  • 2022-01-02: add entry about specialization and how to use the eGPU as a display device

2. Introduction §

I previously wrote about using an eGPU on Gentoo Linux. It was working when using the eGPU display but I never got it to work for accelerating games using the laptop display.

Now, I'm back on NixOS and I got it to work!

3. What is it about? §

My laptop has a thunderbolt connector and I'm using a Razer Core X external GPU case that is connected to the laptop using a thunderbolt cable. This allows to use an external "real" GPU on a laptop but it has performance trade off and on Linux also compatibility issues.

There are three ways to use the nvidia eGPU:

- run the nvidia driver and use it as a normal card with its own display connected to the GPU, not always practical with a laptop

- use optirun / primerun to run programs within a virtual X server on that GPU and then display it on the X server (very clunky, originally created for Nvidia Optimus laptop)

- use Nvidia offloading module (it seems recent and I learned about it very recently)

The first case is easy, just install nvidia driver and use the right card, it should work on any setup. This is the setup giving best performance.

The most complicated setup is to use the eGPU to render what's displayed on the laptop, meaning the video signal has to come back from the thunderbolt cable, reducing the bandwidth.

4. Nvidia offloading §

Nvidia made work in their proprietary driver to allow a program to have its OpenGL/Vulkan calls to be done in a GPU that is not the one used for the display. This allows to throw optirun/primerun for this use case, which is good because they added performance penalty, complicated setup and many problems.

Official documentation about offloading with nvidia driver

5. NixOS §

I really love NixOS and for writing articles it's so awesome, because instead of a set of instructions depending on conditions, I only have to share the piece of config required.

This is the bits to add to your /etc/nixos/configuration.nix file and then rebuild system:

hardware.nvidia.modesetting.enable = true;
hardware.nvidia.prime.sync.allowExternalGpu = true;
hardware.nvidia.prime.offload.enable = true;
hardware.nvidia.prime.nvidiaBusId = "PCI:10:0:0";
hardware.nvidia.prime.intelBusId = "PCI:0:2:0";
services.xserver.videoDrivers = ["nvidia" ];

A few notes about the previous chunk of config:

- only add nvidia to the list of video drivers, at first I was adding modesetting but this was creating troubles

- the PCI bus ID can be found with lspci, it has to be translated in decimal, here my nvidia id is 10:0:0 but in lspci it's 0a:00:00 with 0a being 10 in hexadecimal

NixOS wiki about nvidia offload mode

6. How to use it §

The use of offloading is controlled by environment variables. What's pretty cool is that if you didn't connect the eGPU, it will still work (with integrated GPU).

6.1. Running a command §

We can use glxinfo to be sure it's working, add the environment as a prefix:

__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia glxinfo

6.2. In Steam §

Modify the command line of each game you want to run with the eGPU (it's tedious), by:

__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command%

6.3. In Lutris §

Lutris has a per-game or per-runner setting named "Enable Nvidia offloading", you just have to enable it.

7. Advanced usage / boot specialisation §

Previously I only explained how to use the laptop screen and the eGPU as a discrete GPU (not doing display). For some reasons, I've struggled a LOT to be able to use the eGPU display (which gives more performance because it's hitting less thunderbolt limitations).

I've discovered NixOS "specialisation" feature, allowing to add an alternative boot entry to start the system with slight changes, in this case, this will create a new "external-display" entry for using the eGPU as the primary display device:

  hardware.nvidia.modesetting.enable = true;
  hardware.nvidia.prime.sync.allowExternalGpu = true;
  hardware.nvidia.prime.offload.enable = true;
  hardware.nvidia.prime.nvidiaBusId = "PCI:10:0:0";
  hardware.nvidia.prime.intelBusId = "PCI:0:2:0";
  services.xserver.videoDrivers = ["nvidia" ];

  # external display on the eGPU card
  # otherwise it's discrete mode using laptop screen
  specialisation = {
    external-display.configuration = {
        system.nixos.tags = [ "external-display" ];
        hardware.nvidia.modesetting.enable = pkgs.lib.mkForce false;
        hardware.nvidia.prime.offload.enable = pkgs.lib.mkForce false;
        hardware.nvidia.powerManagement.enable = pkgs.lib.mkForce false;
        services.xserver.config = pkgs.lib.mkOverride 0
  ''
Section "Module"
    Load           "modesetting"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    BusID          "10:0:0"
    Option         "AllowEmptyInitialConfiguration"
    Option         "AllowExternalGpus" "True"
EndSection
'';
    };
  };

With this setup, the default boot is the offloading mode but I can choose "external-display" to use my nvidia card and the screen attached to it, it's very convenient.

I had to force the xserver configuration file because the one built by NixOS was not working for me.

Using awk to pretty-display OpenBSD packages update changes

Written by Solène, on 04 December 2021.
Tags: #openbsd #awk

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1. Introduction §

You use OpenBSD and when you upgrade your packages you often wonder which one is a rebuild and which one is a real version update? The packages updates are logged in /var/log/messages and using awk it's easy to achieve some kind of report.

2. Command line §

The typical update line will display the package name, its version, a "->" and the newer version of the installed package. By verifying if the newer version is different from the original version, we can report updated packages.

awk is already installed in OpenBSD, so you can run this command in your terminal without any other requirement.

awk -F '-' '/Added/ && /->/ { sub(">","",$0) ; if( $(NF-1) != $NF ) { $NF=" => "$NF ; print }}' /var/log/messages

The output should look like this (after a pkg_add -u):

Dec  4 12:27:45 daru pkg_add: Added quirks 4.86  => 4.87
Dec  4 13:01:01 daru pkg_add: Added cataclysm dda 0.F.2v0  => 0.F.3p0v0
Dec  4 13:01:05 daru pkg_add: Added ccache 4.5  => 4.5.1
Dec  4 13:04:47 daru pkg_add: Added nss 3.72  => 3.73
Dec  4 13:07:43 daru pkg_add: Added libexif 0.6.23p0  => 0.6.24
Dec  4 13:40:41 daru pkg_add: Added kakoune 2021.08.28  => 2021.11.08
Dec  4 13:43:27 daru pkg_add: Added kdeconnect kde 1.4.1  => 21.08.3
Dec  4 13:46:16 daru pkg_add: Added libinotify 20180201  => 20211018
Dec  4 13:51:42 daru pkg_add: Added libreoffice 7.2.2.2p0v0  => 7.2.3.2v0
Dec  4 13:52:37 daru pkg_add: Added mousepad 0.5.7  => 0.5.8
Dec  4 13:52:50 daru pkg_add: Added munin node 2.0.68  => 2.0.69
Dec  4 13:53:01 daru pkg_add: Added munin server 2.0.68  => 2.0.69
Dec  4 13:53:14 daru pkg_add: Added neomutt 20211029p0 gpgme sasl 20211029p0 gpgme  => sasl
Dec  4 13:53:20 daru pkg_add: Added nethack 3.6.6p0 no_x11 3.6.6p0  => no_x11
Dec  4 13:58:53 daru pkg_add: Added ristretto 0.12.0  => 0.12.1
Dec  4 14:01:07 daru pkg_add: Added rust 1.56.1  => 1.57.0
Dec  4 14:02:33 daru pkg_add: Added sysclean 2.9  => 3.0
Dec  4 14:03:57 daru pkg_add: Added uget 2.0.11p4  => 2.2.2p0
Dec  4 14:04:35 daru pkg_add: Added w3m 0.5.3pl20210102p0 image 0.5.3pl20210102p0  => image
Dec  4 14:05:49 daru pkg_add: Added yt dlp 2021.11.10.1  => 2021.12.01

3. Limitations §

The command seems to mangle the separators when displaying the result and doesn't work well with flavors packages that will always be shown as updated.

At least it's a good start, it requires a bit more polishing but that's already useful enough for me.

The state of Steam on OpenBSD

Written by Solène, on 01 December 2021.
Tags: #openbsd #gaming #steam

Comments on Fediverse/Mastodon

1. Introduction §

There is a very common question within the OpenBSD community, mostly from newcomers: "How can I install Steam on OpenBSD?".

The answer is: You can't, there is no way, this is impossible, period.

2. Why? §

Steam is a closed source program, while it's now also available on Linux doesn't mean it run on OpenBSD. The Linux Steam version is compiled for linux and without the sources we can't port it on OpenBSD.

Even if Steam was able to be installed and could be launched, games are not made for OpenBSD and wouldn't work either.

On FreeBSD it may be possible to install Windows Steam using Wine, but Wine is not available on OpenBSD because it require some specific Kernel memory management we don't want to implement for security reasons (I don't have the whole story), but FreeBSD also has a Linux compatibility mode to run Linux binaries, allowing to use programs compiled for Linux. This linux emulation layer has been dropped in OpenBSD a few years ago because it was old and unmaintained, bringing more issues than helping.

So, you can't install Steam or use it on OpenBSD. If you need Steam, use a supported operating system.

I wanted to make an article about this in hope my text will be well referenced within search engines, to help people looking for Steam on OpenBSD by giving them a reliable answer.

Nethack: end of Sery the Tourist

Written by Solène, on 27 November 2021.
Tags: #nethack #gaming

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Hello, if you remember my previous publications about Nethack and my character "Sery the tourist", I have bad news. On OpenBSD, nethack saves are stored in /usr/local/lib/nethackdir-3.6.0/logfile and obviously I didn't save this when changing computer a few months ago.

I'm very sad of this data loss because I was enjoying a lot telling the story of the character while playing. Sery reached 7th floor while being a Tourist, which is incredible given all the nethack plays I've done and this one was going really well.

I don't know if you readers enjoyed that kind of content, if so please tell me so I may start a new game and write about it.

As an end, let's say Sery stayed too long in 7th floor and the Langoliers came to eat the Time of her reality.

Langoliers on Stephen King wiki fandom

Simple network dashboard with vnstat

Written by Solène, on 25 November 2021.
Tags: #openbsd #networking #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

Hi! If you run a server or a router, you may want to have a nice view of the bandwidth usage and statistics. This is easy and quick to achieve using vnstat software. It will gather data regularly from network interfaces and store it in rrd files, it's very efficient and easy to use, and its companion program vnstati can generate pictures, perfect for easy visualization.

My simple router network dashboard with vnstat
My simple router network dashboard with vnstat

vnstat project homepage

Take a look at Abhinav's Notes for a similar setup with NixOS

2. Setup (on OpenBSD) §

Simply install vnstat and vnstati packages with pkg_add. All the network interfaces will be added to vnstatd databases to be monitored.

# pkg_add vnstat vnstati
# rcctl enable vnstatd
# rcctl start vnstatd
# install -d -o _vnstat /var/www/htdocs/dashboard

Create a script in /var/www/htdocs/dashboard and make it executable:

#!/bin/sh

cd /var/www/htdocs/dashboard/ || exit 1

# last 60 entries of 5 minutes stats
vnstati --fiveminutes 60 -o 5.png

# vertical summary of last two days
# refresh only after 60 minutes
vnstati -c 60 -vs -o vs.png

# daily stats for 14 last days
# refresh only after 60 minutes
vnstati -c 60 --days 14 -o d.png

# monthly stats for last 5 months
# refresh only after 300 minutes
vnstati -c 300 --months 5 -o m.png

and create a simple index.html file to display pictures:

<html>
    <body>
        <div style="display: inline-block;">
                <img src="vs.png" /><br />
                <img src="d.png" /><br />
                <img src="m.png" /><br />
        </div>
        <img src="5.png" /><br />
    </body>
</html>

Add a cron as root to run the script every 10 minutes using _vnstat user:

# add /usr/local/bin to $PATH to avoid issues finding vnstat
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin

*/10  *  *  *  * -ns su -m _vnstat -c "/var/www/htdocs/dashboard/vnstat.sh"

My personal crontab runs only from 8h to 23h because I will never look at my dashboard while I'm sleeping so I don't need to keep it updated, just replace * by 8-23 for the hour field.

3. Http server §

Obviously you need to serve /var/www/htdocs/dashboard/ from your http server, I won't cover this step in the article.

4. Conclusion §

Vnstat is fast, light and easy to use, but yet it produces nice results.

As an extra, you can run the vnstat commands (without the i) and use the raw text output to build an pure text dashboard if you don't want to use pictures (or http).

OpenBSD and Linux comparison: data transfer benchmark

Written by Solène, on 14 November 2021.
Tags: #openbsd #networking

Comments on Fediverse/Mastodon

1. Introduction §

I had a high suspicion about something but today I made measurements. My feeling is that downloading data from OpenBSD use more "upload data" than on other OS

I originally thought about this issue when I found that using OpenVPN on OpenBSD was limiting my download speed because I was reaching the upload limit of my DSL line, but it was fine on Linux. From there, I've been thinking since then that OpenBSD was using more out data but I never measured anything before.

2. Testing protocol §

Now that I have an OpenBSD router it was easy to make the measures with a match rule and a label. I'll be downloading a specific file from a specific server a few times with each OS, so I'm adding a rule matching this connection.

match proto tcp from 10.42.42.32 to 145.238.169.11 label benchmark

Then, I've been downloading this file three times per OS and resetting counter after each download and saved the results from "pfctl -s labels" command.

OpenBSD comp70.tgz file from an OpenBSD mirror

The variance of each result per OS was very low, I used the average of each columns as the final result per OS.

3. Raw results §

OS        total packets    total bytes    packets OUT    bytes OUT    packets IN    bytes IN
-----     -------------    -----------    -----------    ---------    ----------    --------
OpenBSD   175348           158731602      72068          3824812      10328         154906790
OpenBSD   175770           158789838      72486          3877048      10328         154912790
OpenBSD   176286           158853778      72994          3928988      10329         154924790
Linux     154382           157607418      51118          2724628      10326         154882790
Linux     154192           157596714      50928          2713924      10326         154882790
Linux     153990           157584882      50728          2705092      10326         154879790

4. About the results §

A quick look will show that OpenBSD sent +42% OUT packets compared to Linux and also +42% OUT bytes, meanwhile the OpenBSD/Linux IN bytes ratio is nearly identical (100.02%).

Chart showing the IN and OUT packets of Linux and OpenBSD side by side
Chart showing the IN and OUT packets of Linux and OpenBSD side by side

5. Conclusion §

I'm not sure what to conclude except that now, I'm sure there is something here requiring investigation.

How I ended up liking GNOME

Written by Solène, on 10 November 2021.
Tags: #life #unix #gnome

Comments on Fediverse/Mastodon

1. Introduction §

Hi! This was a while without much activity on my blog, the reason is that I stabbed through my right index with a knife by accident, the injury was so bad I can barely use my right hand because I couldn't move my index at all without pain. So I've been stuck with only my left hand for a month now. Good news, it's finally getting better :)

Which leads me to the topic of this article, why I ended liking GNOME!

2. Why I didn't use GNOME §

I will first start about why I didn't use it before. I like to try everything all the time, I like disruption, I like having an hostile (desktop/shell/computer) environment to stay sharp and not being stuck on ideas.

My current setup was using Fvwm or Stumpwm, mostly keyboard driven, with many virtual desktop to spatially regroup different activities. However, with an injured hand, I've been facing a big issue, most of my key binding were for two hands and it seemed too weird for me to change the bindings to work with one hand.

I tried to adapt using only one hand, but I got poor results and using the cursor was not very efficient because stumpwm is hostile to cursor and fvwm is not really great for this either.

3. The road to GNOME §

With only one hand to use my computer, I found the awesome program ibus-typing-booster to help me typing by auto completing words (a bit like on touchscreen phones), it worked out of the box with GNOME due to the ibus integration working well. I used GNOME to debug the package but ended liking it in my current condition.

How do I like it now, while I was pestling about it a few months ago as I found it very confusing? Because it's easy to use and spared me movements with my hands, absolutely.

  • The activity menu is easy to browse, icons are big, dock is big. I've been using a trackball with my left hand instead of the usual right hand, aiming at a small task bar was super hard so I was happy to have big icons everywhere, only when I wanted them
  • I actually always liked the alt+tab for windows and alt+² (on my keyboard the key up to TAB is ², must be ~ for qwerty keyboards) for switching into same kind of window
  • alt+tab actually display everything available (it's not per virtual desktop)
  • I can easily view windows or move them between virtual desktop when pressing "super" key

This is certainly doing in MATE or Xfce too without much work, but it's out of the box with GNOME. It's perfectly usable without knowing any keyboard shortcut.

4. Mixed feelings §

I'm pretty sure I'll return to my previous environment once my finger/hand because I have a better feeling with it and I find it more usable. But I have to thanks the GNOME project to work on this desktop environment that is easy to use and quite accessible.

It's important to put into perspective when dealing with desktop environment. GNOME may not be the most performing and ergonomic desktop, but it's accessible, easy to use and forgiving people who doesn't want to learn tons of key bindings or can't do them.

5. Conclusion §

There is a very recurrent question I see on IRC or forums: what's the best desktop environment/window manager? What are YOU using? I stopped having a bold opinion about this topic, I simply reply there are many desktop environments because they are many kind of people and the person asking the question need to find the right one to suiting them.

6. Update (2021-11-11) §

Using the xfdashboard program and assigning it to Super key allows to mimic the GNOME "activity" view in your favorite window manager: choosing windows, moving them between desktops, running applications. I think this can easily turn any window manager into something more accessible, or at least "GNOME like".

What if Internet stops? How to rebuild an offline federated infrastructure using OpenBSD

Written by Solène, on 21 October 2021.
Tags: #openbsd #distributed #opensource #nocloud

Comments on Fediverse/Mastodon

1. Introduction §

What if we lose Internet tomorrow and we stop building computers? What would you want on your computer in the eventuality we would still have *some* power available to run it?

I find it to be an interesting exercise in the continuity of my old laptop challenge.

2. Bootstrapping §

My biggest point would be that my computer could be used to replicate itself to other computer owners, give them the data so they can spread it again. Data copied over and over will be a lot more resilient than a single copy with a few local backups (local as in same city at best because there is no Internet).

Because most people's computers relying on the Internet to have data turned into useless bricks, I think everyone would be glad to be part of an useful infrastructure that can replicate and extend.

3. Essentials §

I think I would have to argue this is very useful to have computers and knowledge they can carry if we are short on electricity for running computers. We would want science knowledge (medicine, chemistry, physics, mathematics) but also history and other topics in the long run. We would also require maps of the local region/country to make long term plans and help decisions and planning to build infrastructures (pipes, roads, lines). We would require software to display but also edit these data.

Here is a list of sources I would keep synced on my computer.

  • wikipedia dumps (by topics so it's lighter to distribute)
  • openstreetmap local maps
  • OpenBSD source code
  • OpenBSD ports distfiles
  • kiwix and openstreetmap android APK files

The wikipedia dumps in zim format are very practical to run an offline wikipedia, we would require some OpenBSD programs to make it work but we would like more people to have them, Android tablets and phones are everywhere, small and doesn't draw much battery, I'd distribute the wikipedia dumps along with a kiwix APK file to view them without requiring a computer. Keeping the sources of the Android programs would be a wise decision too.

As for maps, we can download areas on openstreetmap and rework them with Qgis on OpenBSD and redistribute maps and a compatible viewer for Android devices with the OSMand~ free software app.

It would be important to keep the data set rather small, I think under 100 GB because it would be complicated to have a 500GB requirement for setting up a new machine that can re-propagate the data set.

If I would ever need to do that, the first time would be to make serious backups of the data set using multiples copies on hard drives that I would I hand to different people. Once the propagation process is done, it matters less because I could still gather the data somewhere.

Kiwix compatible data sets (including Wikipedia)

Android Kiwix app on F-droid

Android OSMand~ app for OSM maps on F-droid

4. Why OpenBSD? §

I'd choose OpenBSD because it's a system I know well, but also because it's easy to hack on it to make changes on the kernel. If we ever need to connect a computer to an industrial machine, I'd rather try to port if on OpenBSD.

This is also true for the ports library, with all the distfiles it's possible to rebuild packages for multiple architectures, allowing to use older computers that are not amd64, but also easily patching distfiles to fix issues or add new features. Carrying packages without their sources would be a huge mistake, you will have a set of binary blobs that can't evolve.

OpenBSD is also easy to install and it works fine most of the time. I'd imagine automatic installation process from USB or even from PXE, and then share all the data so other people can propagate installation and data again.

This would also work with another system of course, the point is to keep the sources of the system and of its package to be able to rebuild the system for older supported architecture but also be able to enhance and work on the sources for bug fixing and new features.

5. Distributing §

I think a very nice solution would be to use Git, there are plugins to handle binary data so the repository doesn't grow over time. Git is decentralized, you can get updates from someone who receives an update from someone else and git can also report if someone messed with the history.

We could imagine some well known places running a local server with a WiFi hotspot that can receive updates from someone allowed to (using ssh+git) push updates to a git repository. There could be repositories for various topics like: news, system update, culture (music, videos, readings), maybe some kind of social network like twtxt. Anyone could come and sync their local git repository to get the news and updates, and be able to spread it again.

twtxt project github page

6. Conclusion §

This is often a topic I have in mind when I think at why we are using computers and what makes them useful. In this theoretic future which is not "post-apocalyptic" but just something went wrong and we have a LOT of computers that become useless. I just want to prove that computers can still be useful without the Internet but you just need to understand their genuine purpose.

I'd be interested into what others would do, please let me know if you want to write on that topic :)

Use fzf for ksh history search

Written by Solène, on 17 October 2021.
Tags: #openbsd #shell #ksh #fzf

Comments on Fediverse/Mastodon

1. Introduction §

fzf is a powerful tool to interactively select a line among data piped to stdin, a simple example is to pick a line in your shell history and it's my main fzf use.

fzf ships with bindings for bash, zsh or fish but doesn't provide anything for ksh, OpenBSD default shell. I found a way to run it with Ctrl+R but it comes with a limitation!

This setup will run fzf for looking a history line with Ctrl+R and will run it without allowing you to edit the line! /!\

2. Configuration §

In your interactive shell configuration file (should be the one set in $ENV), add the following function and binding, it will rebind Ctrl+R to fzf-histo function that will look into your shell history.

function fzf-histo {
    RES=$(fzf --tac --no-sort -e < $HISTFILE)
    test -n "$RES" || exit 0
    eval "$RES"
}

bind -m ^R=fzf-histo^J

Reload your file or start a new shell, Ctrl+R should now run fzf for a more powerful history search. Don't forget to install fzf package.

Typing faster with assistive technology

Written by Solène, on 16 October 2021.
Tags: #accessibility #a11y

Comments on Fediverse/Mastodon

1. Introduction §

This article is being written only using my left hand with the help of ibus-typing-booster program.

ibus-typing-booster project

The purpose of this tool is to assist the user by proposing words while typing, a bit like smartphones do. It can be trained with a dictionary, a text file but also learn from user inputs over time.

A package for OpenBSD is on the tracks.

2. Installation §

This program requires ibus to work, on Gnome it is already enabled but in other environments some configuration are required. Because this may be subject to change over time and duplicating information is bad, I'll give the links for configuring ibus-typing-booster.

How to enable ibus-typing-booster

3. How to use §

Once you have setup ibus and ibus-typing-booster you should be able to switch from normal input to assisted input using "super"+space.

When you type with ibus-typing-booster enabled, with default settings, the input should be underlined to show a suggestion can be triggered using TAB key. Then, from a popup window you can pick a word by using TAB to cycle between the suggestions and pressing space to validate, or use the F key matching your choice number (F1 for first, F2 for second etc...) and that's all.

4. Configuration §

There are many ways to configure it, suggestions can be done inline while typing which I think is more helpful when you type slowly and you want a quick boost when the suggestion is correct. The suggestions popup can be vertical or horizontal, I personally prefer horizontal which is not the default. Colors and key bindings can changed.

5. Performance §

While I type very fast when I have both my hands, using one hand requires me to look the keyboard and make a lot of moves with my hand. This work fine and I can type reasonably fast but this is extremely exhausting and painful for my hand. With ibus-typing-booster I can type full sentences with less efforts but a bit slower. However this is a lot more comfortable than typing everything using my hand.

6. Conclusion §

This is an assistive technology easy to setup and that can be a life changer for disabled users who can make use of it.

This is not the first time I'm temporarily disabled in regards to using a keyboard, I previously tried a mirrored keyboard layout reverting keys when pressing caps lock, and also Dasher which allow to make words from simple movements such as moving mouse cursor. I find this ibus plugin to be easier to integrate for the brain because I just type with my keyboard in the programs, with Dasher I need to cut and paste content, and with mirrored layout I need to focus on the layout change.

I am very happy of it.

Full WireGuard setup with OpenBSD

Written by Solène, on 09 October 2021.
Tags: #openbsd #wireguard #vpn

Comments on Fediverse/Mastodon

1. Introduction §

We want all our network traffic to go through a WireGuard VPN tunnel automatically, both WireGuard client and server are running OpenBSD, how to do that? While I thought it was simple at first, it soon became clear that the "default" part of the problem was not easy to solve, fortunately there are solutions.

This guide should work from OpenBSD 6.9.

pf.conf man page about NAT

WireGuard interface man page

ifconfig man page, WireGuard section

2. Setup §

For this setup I assume we have a server running OpenBSD with a public IP address (1.2.3.4 for the example) and an OpenBSD computer with Internet connectivity.

Because you want to use the WireGuard tunnel as the default route, you can't define a default route through WireGuard as this, that would prevent our interface to reach the WireGuard endpoint to make the tunnel working. We could play with the routing table by deleting the default route found on the interface, create a new route to reach the WireGuard server and then create a default route through WireGuard, but the whole process is fragile and there is no right place to trigger a script doing this.

Instead, you can assign the network interface used to access the Internet to the rdomain 1, configure WireGuard to reach its remote peer through rdomain 1 and create a default route through WireGuard on the rdomain 0. Quick explanation about rdomain: they are different routing tables, default is rdomain 0 but you can create new routing tables and run commands using a specific routing table with "route -T 1 exec ping perso.pw" to make a ping through rdomain 1.


    +-------------+
    |   server    | wg0: 192.168.10.1
    |             |---------------+
    +-------------+               |
           | public IP            |
           | 1.2.3.4              |
           |                      |
           |                      |
    /\/\/\/\/\/\/\                |WireGuard
    |  internet  |                |VPN
    \/\/\/\/\/\/\/                |
           |                      |
           |                      |
           |rdomain 1             |
    +-------------+               |
    |   computer  |---------------+
    +-------------+ wg0: 192.168.10.2
                    rdomain 0 (default)

3. Configuration §

The configuration process will be done in this order:

  1. create the WireGuard interface on your computer to get its public key
  2. create the WireGuard interface on the server to get its public key
  3. configure PF to enable NAT and enable IP forwarding
  4. reconfigure computer's WireGuard tunnel using server's public key
  5. time to test the tunnel
  6. make it default route

Our WireGuard server will accept connections on address 1.2.3.4 at the UDP port 4433, we will use the network 192.168.10.0/24 for the VPN, the server IP on WireGuard will be 192.168.10.1 and this will be our future default route.

3.1. On your computer §

We will make a simple script to generate the configuration file, you can easily understand what is being done. Replace "1.2.3.4 4433" by your IP and UDP port to match your setup.

PRIVKEY=$(openssl rand -base64 32)
cat <<EOF > /etc/hostname.wg0
wgkey $PRIVKEY
wgpeer wgendpoint 1.2.3.4 4433 wgaip 0.0.0.0/0
inet 192.168.10.2/24
up
EOF

# start interface so you can get the public key
# we should have an error here, this is normal
sh /etc/netstart wg0

PUBKEY=$(ifconfig wg0 | grep 'wgpubkey' | cut -d ' ' -f 2)
echo "You need $PUBKEY to setup the remote peer"

3.2. On the server §

3.2.1. WireGuard §

Like we did on the computer, we will use a script to configure the server. It's important to get the PUBKEY displayed in the previous step.

PUBKEY=PASTE_PUBKEY_HERE
PRIVKEY=$(openssl rand -base64 32)

cat <<EOF > /etc/hostname.wg0
wgkey $PRIVKEY
wgpeer $PUBKEY wgaip 192.168.10.0/24
inet 192.168.10.1/24
wgport 4433
up
EOF

# start interface so you can get the public key
# we should have an error here, this is normal
sh /etc/netstart wg0

PUBKEY=$(ifconfig wg0 | grep 'wgpubkey' | cut -d ' ' -f 2)
echo "You need $PUBKEY to setup the local peer"

Keep the public key for next step.

3.3. Firewall §

You want to enable NAT so you can reach the Internet through the server using WireGuard, edit /etc/pf.conf to add the following line (after the skip lines):

pass out quick on egress from wg0:network to any nat-to (egress)

Reload with "pfctl -f /etc/pf.conf".

NOTE: if you block all incoming traffic by default, you need to open UDP port 4433. You will also need to either skip firewall on wg0 or configure PF to open what you need. This is beyond the scope of this guide.

3.4. IP forwarding §

We need to enable IP forwarding because we will pass packets from an interface to another, this is done with "sysctl net.inet.ip.forwarding=1" as root. To make it persistent across reboot, add "net.inet.ip.forwarding=1" to /etc/sysctl.conf (you may have to create the file).

From now, the server should be ready.

3.5. On your computer §

Edit /etc/hostname.wg0 and paste the public key between "wgpeer" and "wgaip", the public key is wgpeer's parameter. Then run "sh /etc/netstart wg0" to reconfigure your wg0 tunnel.

After this step, you should be able to ping 192.168.10.1 from your computer (and 192.168.10.2 from the server). If not, please double check the WireGuard and PF configurations on both side.

3.6. Default route §

This simple setup for the default route will truly make WireGuard your default route. You have to understand services listening on all interfaces will only attach to WireGuard interface because it's the only address in rdomain 0, if needed you can use a specific routing table for a service as explained in rc.d man page.

Replace the line "up" with the following:

wgrtable 1
up
!route add -net default 192.168.10.1

Your configuration file should look like this:

wgkey YOUR_KEY
wgpeer YOUR_PUBKEY wgendpoint REMOTE_IP 4433 wgaip 0.0.0.0/0
inet 192.168.10.2/24
wgrtable 1
up
!route add -net default 192.168.10.1

Now, add "rdomain 1" to your network interface used to reach the Internet, in my setup it's /etc/hostname.iwn0 and it looks like this.

join network wpakey superprivatekey
join home wpakey notsuperprivatekey
rdomain 1
up
autoconf

Now, you can restart network with "sh /etc/netstart" and all the network should pass through the WireGuard tunnel.

4. Handling DNS §

Because you may use a nameserver in /etc/resolv.conf that was provided by your local network, it's not reachable anymore. I highly recommend to use unwind (in every case anyway) to have a local resolver, or modify /etc/resolv.conf to use a public resolver.

unwind can be enabled with "rcctl enable unwind" and "rcctl start unwind", from OpenBSD 7.0 you should have resolvd running by default that will rewrite /etc/resolv.conf if unwind is started, otherwise you need to write "nameserver 127.0.0.1" in /etc/resolv.conf

5. Bypass VPN §

If you need for some reason to run a program and not route its traffic through the VPN, it is possible. The following command will run firefox using the routing table 1, however depending on the content of your /etc/resolv.conf you may have issues resolving names (because 127.0.0.1 is only reachable on rdomain 0!). So a simple fix would be to use a public resolver if you really need to do so often.

route -T 1 exec firefox

route man page about exec command

6. WireGuard behind a NAT §

If you are behind a NAT you may need to use the KeepAlive option on your WireGuard tunnel to keep it working. Just add "wgpka 20" to enable a KeepAlive packet every 20 seconds in /etc/hostname.wg0 like this:

wgpeer YOUR_PUBKEY wgendpoint REMOTE_IP 4433 wgaip 0.0.0.0/0 wgpka 20
[....]

ifconfig man page explaining wgpka parameter

7. Conclusion §

WireGuard is easy to deploy but making it a default network interface adds some complexity. This is usually simpler for protocols like OpenVPN because the OpenVPN daemon can automatically do the magic to rewrite the routes (and it doesn't do it very well) and won't prevent non-VPN access until the VPN is connected.

Port of the week: foliate

Written by Solène, on 04 October 2021.
Tags: #openbsd #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

Today I wanted to share with you about the program Foliate, a GTK Ebook reader with interesting features. First, there aren't many epub readers available on OpenBSD (and also on Linux).

Foliate project website

2. How to install §

On OpenBSD, a simple "pkg_add foliate" and you are done.

3. Features §

Foliate supports multiple features such as:

  • bookmarks
  • table of content
  • annotations in the document (including import / export to share and save your annotations)
  • font and rendering: you can choose font, margins, spacing
  • color scheme: Foliate comes with a dozen of color scheme and can be customized
  • library management: all your books available in one place with the % of reading of each

4. Port of the week §

Because it's easy to use, its feature and that it works very well compared to alternatives this port is nominated for the port of the week!

Story of making the OpenBSD Webzine

Written by Solène, on 01 October 2021.
Tags: #openbsd #webzine

Comments on Fediverse/Mastodon

1. Introduction §

Hello readers! I just started a Webzine dedicated to the OpenBSD project and community. I'd like to tell you the process of its creation.

The OpenBSD Webzine

2. Idea §

A week ago I joked on an french OpenBSD IRC channel that it would be nice to do a webzine to gather some quotes and links about OpenBSD, I didn't thought it would be real a few days later. OpenBSD has a small community and even if we can get some news from Mastodon, Twitter, watching new commits, writing blog articles about stuff, we had nothing gathering all of that. I can't imagine most OpenBSD users being able or willing to follow everything happening in the project, so I thought a Webzine targeting average OpenBSD users would be fine. The ultimate accomplishment would be that when we release a new Webzine issue, readers would enjoy reading it with a nice cup of their favorite drink, like if it was one's favorite hobby 'zine.

3. Technology doesn't matter §

At first I wanted the Webzine to look like a news paper, so I tried to use Scribus (used to make magazines and serious stuff) and make a mockup to see what it would look like. Then I shared it with a small French community and some people suggested I should use LaTeX for the job, I replied it was not great for handling the layout exactly as I wanted but I challenged that person to show me something done with LaTeX that looks better than my Scribus mockup.

One hour later, that person came with a PDF generated from LaTeX with the same content, and it looked very great! I like LaTeX but I couldn't believe it could be used efficiently for this job. I immediately made changes to my Scribus version to improve it, taking the LaTeX PDF version as a model and I released a new version. At that time, I had two PDF generated from two different tools.

A few people suggested me to make a version using mdoc, I joked because it wasn't serious, but because boredom is a powerful driving force I decided to reuse the content of my mockup to do another mockup with mdoc. I chose to export it to html and had to write a simple CSS style sheet to make it look nice, but ultimately mdoc export had some issues and required to apply changes with sed to the output to fix the HTML rendering to not look like a man page misused for something else.

Anyway, I got three mockups of the same Webzine example and decided to use Scribus to export its version as a SVG file and embed it in a html file for allowing web browsers to display it natively.

I asked the Mastodon community (thank you very much to everyone who participated!) which version they liked the most and I got many replies: the mdoc html version was the most preferred by with 41%, while 32% liked the SVG-in-html version and 27% the PDF. Results were very surprising! The version I liked the least was the most preferred, but there were reasons underneath.

The PDF version was not available in web browsers (or at least didn't display natively) and some readers didn't enjoy that. As for the SVG version it didn't work well on mobile phones and both versions didn't work at all in console web clients (links, lynx, w3m). There was also accessibility concerns with the PDF or SVG for screen readers / text-to-speech users and I wanted the Webzine to be available for everyone so both formats were a no-go.

Ultimately, I decided the best way would be to publish the Webzine as HTML if I wanted it to look nice and being accessible on any device for any users. I'm not a huge fan of web and html, but it was the best choice for the readers. From this point, I started working with a few people (still from the same French OpenBSD community) to decide how to make it as HTML, from this moment I wasn't alone anymore in the project.

In the end, the issue is done by writing html "by hand" because it just works and doesn't require extra complexity layer. Simple html is not harder than markdown or LaTeX or weird format because it doesn't require extra tweaks after conversion.

4. Community §

I created a git repository on tildegit.org where I already host some projects so we could work on this project as a team. Requirements and what we wanted to do was getting refined a bit more every day. I designed a simplistic framework in shell that would suits our needs. It wasn't long before we got the framework to generate html pages, some styles changes happened all along the development and I think this will still happen regularly in the near future. We had a nice base to start writing content.

We had to choose a licensing, contributions processes, who is doing what etc... Fun times, I enjoyed this a lot. Our goal was to make a Webzine that would work everywhere, without JS, with a dark mode and still usable on phone or console clients so we regularly checked all of that and reported issues that were getting fixed really quickly.

5. Simple framework §

Let's talk a bit about the website framework. There is a simple hierarchy of directories, one used to write each issue in a dedicated directory, a Makefile to build everything, parts that are common to each generated pages (containing style, html header and footer). Each issue is made from of lot of file starting with a number, so when a page is generated by the concatenation of all the parts parts we can keep the numbers ordering.

It may not be optimized CPU wise, but concatenating parts allow reusing common parts (mainly header and footer) but also working on smaller files: each file of the issues represents a section of it (Quote, Going further, Headlines etc...).

6. Conclusion §

This is a fantastic journey, we are starting to build a solid team for the webzine. Everyone is allowed to contribute. My idea was to give every reader a small slice of the OpenBSD project life every so often and I think we are on good tracks now. I'd like to thanks all the people from the https://openbsd.fr.eu.org/ community who joined me at the early stages to make this project great.

Git repository of the OpenBSD Webzine (if you want to contribute)

Measuring power efficiency of a CPU frequency scheduler on OpenBSD

Written by Solène, on 26 September 2021.
Tags: #openbsd #power #efficiency

Comments on Fediverse/Mastodon

1. Introduction §

I started to work on the OpenBSD code dealing with the CPU frequency scaling. The current automatic logic is a trade-off between okay performance and okay battery. I'd like the auto policy to be different when on battery and when on current (for laptops) to improve battery life for nomad users and performance for people connected to the grid.

I've been able to make raw changes to produce this effect but before going further, I wanted to see if I got any improvement in regards to battery life and to which extent if it was positive.

In the incoming sections of the article I will refer to Wh unit, meaning Watt-hour. It's a measurement unit for a quantity of energy used, because energy used is absolutely not linear, we can make an average of the usage and scale it to one hour so it's easy to compare. An oven drawing 1 kW when on and being on for an hour will use 1 kWh (one kilowatt-hour), while an electric heater drawing 2 kW when on and turned on for 30 minutes will use 1 kWh too.

Kilowatt Hour explanation from Wikipedia

2. How to understand power usage for nomad users §

While one may think that the faster we do a task, the less time the system stay up and the less battery we use, it's not entirely true for laptops or computers.

There are two kinds of load on a system: interactive and non-interactive. In non-interactive mode, let's imagine the user powers on the computer, run a job and expect it to be finished as soon as possible and then shutdown the computer. This is (I think) highly unusual for people using a laptop on battery. Most of the time, users with a laptop will want their computer to be able to stay up as long as possible without having to charge.

In this scenario I will call interactive, the computer may be up with lot of idle time where the human operator is slowly typing, thinking or reading. Usually one doesn't power off a computer and power it on again while the person is sitting in front of the laptop. So, for a given task among the main task "staying up" may not be more efficient (in regards to battery) if it takes less time, because whatever the time it will take to do X() the system will stay up after.

3. Testing protocol §

Here is the protocol I did for the testing "powersaving" frequency policy and then the regular auto policy.

  1. Clean package of games/gzdoom
  2. Unplug charger
  3. Dump hw.sensors.acpibat1.watthour3 value in a file (it's the remaining battery in Wh)
  4. Run compilation of the port games/gzdoom with dpb set to use all cores
  5. Dump watthour3 value again
  6. Wait until 18 minutes and 43 seconds
  7. Dump watthour3 value again

Why games/gzdoom? It's a port I know can be compiled with parallel build allowing to use all CPU and I know it takes some times but isn't too short too.

Why 18 minutes and 43 seconds? It's the time it takes for the powersaving policy to compile games/gzdoom. I needed to compare the amount of energy used by both policies for the exact same time with the exact same job done (remember the laptop must be up as long as possible, so we don't shutdown it after compiling gzdoom).

I could have extended the duration of the test so the powersaving would have had some idle time but given the idle time is drawing the exact same power with both policies, that would have been meaningless.

4. Results §

I'm planning to add results for the lowest and highest modes (apm -L and apm -H) to see the extremes.

4.1. Compilation time §

As expected, powersaving was slower than the auto mode, 18 minutes and 43 seconds versus 14 minutes and 31 seconds for the auto policy.

Policy		Compile time	Idle time
------		------------	---------
powersaving	1123		0
auto		871		252
Chart showing the difference in time spent for the two policies
Chart showing the difference in time spent for the two policies

4.2. Energy used §

We see that the powersaving used more energy for the duration of the compilation of gzdoom, 5.9 Wh vs 5.6 Wh, but as we don't turn off the computer after the compilation is done, the auto mode also spent a few minutes idling and used 0.74 Wh in that time.

Policy		Compile power	Idle power	Total (Wh)
------		------------	---------	----------
powersaving	5,90		0,00		5,90
auto		5,60		0,74		6,34
Chart showing the difference in energy used for the two policies
Chart showing the difference in energy used for the two policies

5. Conclusion §

For the same job done: compiling games/gzdoom and stay on for 18 minutes and 43 seconds, the powersaving policy used 5.90 Wh while the auto mode used 6.34 Wh. This is a saving of 6.90% of power.

This is a testing policy I made for testing purposes, it may be too conservative for most people, I don't know. I'm currently playing with this and with a reproducible benchmark like this one I'm able to compare results between changes in the scheduler.

Reuse of OpenBSD packages for trying runtime

Written by Solène, on 19 September 2021.
Tags: #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

So, I'm currently playing with OpenBSD trying each end user package (providing binaries) and see if they work when installed alone. I needed a simple way to keep packages downloaded and I didn't want to go the hard way by using rsync on a package mirror because it would waste too much bandwidth and would take too much time.

The most efficient way I found rely on a cache and ordering the source of packages.

2. pkg_add mastery §

pkg_add has a special variable named PKG_CACHE that when it's set, downloaded packages are copied in this directory. This is handy because every time I will install a package, all the packages downloaded by will kept in that directory.

The other variable that interests us for the job is PKG_PATH because we want pkg_add to first look up in $PKG_CACHE and if not found, in the usual mirror.

I've set this in my /root/.profile

export PKG_CACHE=/home/packages/
export PKG_PATH=${PKG_CACHE}:http://ftp.fr.openbsd.org/pub/OpenBSD/snapshots/packages/amd64/

Every time pkg_add will have to get a package, it will first look in the cache, if not there it will download it in the mirror and then store it in the cache.

3. Saving time removing packages §

Because I try packages one by one, installing and removing dependencies takes a lot of time (I'm using old hardware for the job). Instead of installing a package, deleting it and removing its dependencies, it's easier to work with manually installed packages and once done, remove dependencies, this way you will keep already installed dependencies that will be required for the next package.

#!/bin/sh

# prepare the packages passed as parameter as a regex for grep
KEEP=$(echo $* | awk '{ gsub(" ","|",$0); printf("(%s)", $0) }')

# iterate among the manually installed packages
# but skip the packages passed as parameter
for pkg in $(pkg_info -mz | grep -vE "$KEEP")
do
	# instead of deleting the package
	# mark it installed automatically
	pkg_add -aa $pkg
done

# install the packages given as parameter
pkg_add $*

# remove packages not required anymore
pkg_delete -a

This way, I can use this script (named add.sh) "./add.sh gnome" and then reuse it with "./add.sh xfce", the common dependencies between gnome and xfce packages won't be removed and reinstalled, they will be kept in place.

4. Conclusion §

There are always tricks to make bandwidth and storage more efficient, it's not complicated and it's always a good opportunity to understand simple mechanisms available in our daily tools.

How to use cpan or pip packages on Nix and NixOS

Written by Solène, on 18 September 2021.
Tags: #nixos #nix #perl #python

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1. Introduction §

When using Nix/NixOS and requiring some development libraries available in pip (for python) or cpan (for perl) but not available as package, it can be extremely complicated to get those on your system because the usual way won't work.

2. Nix-shell §

The command nix-shell will be our friend here, we will define a new environment in which we will have to create the package for the libraries we need. If you really think this library is useful, it may be time to contribute to nixpkgs so everyone can enjoy it :)

The simple way to invoke nix-shell is to use packages, for example the command nix-shell -p python38Packages.pyyaml will give you access to the python library pyyaml for Python 3.8 as long as you run python from this current shell.

The same way for Perl, we can start a shell with some packages available for databases access, multiples packages can be passed to "nix-shell -p" like this: nix-shell -p perl532Packages.DBI perl532Packages.DBDSQLite.

3. Defining a nix-shell §

Reading the explanations found on a blog and help received on Mastodon, I've been able to understand how to use a simple nix-shell definition file to declare new cpan or pip packages.

Mattia Gheda's blog: Introduction to nix-shell

Mastodon toot from @cryptix@social.coop how to declare a python package on the fly

What we want is to create a file that will define the state of the shell, it will contain new packages needed but also the list of packages.

4. Skeleton §

Create a file with the nix extension (or really, whatever the file name you want), special file name "shell.nix" will be automatically picked up when using "nix-shell" instead of passing the file name as parameter.

with (import <nixpkgs> {});
let
    # we will declare new packages here
in
mkShell {
  buildInputs = [ ]; # we will declare package list here
}

Now we will see how to declare a python or perl library.

4.1. Python §

For python, we need to know the package name on pypi.org and its version. Reusing the previous template, the code would look like this for the package Crossplane

with (import <nixpkgs> {}).pkgs;
let
  crossplane = python37.pkgs.buildPythonPackage rec {
    pname = "crossplane";
    version = "0.5.7";
    src = python37.pkgs.fetchPypi {
      inherit pname version;
      sha256 = "a3d3ee1776bcccebf7a58cefeb365775374ab38bd544408117717ccd9f264f60";
    };
    
    meta = { };
  };


in
mkShell {
  buildInputs = [ crossplane python37 ];
}

If you need another library, replace crossplane variable name but also pname value by the new name, don't forget to update that name in buildInputs at the end of the file. Use the correct version value too.

There are two references to python37 here, this implies we need python 3.7, adapt to the version you want.

The only tricky part is the sha256 value, the only way I found to find it easily is the following.

  1. declare the package with a random sha256 value (like echo hello | sha256)
  2. run nix-shell on the file, see it complaining about the wrong checksum
  3. get the url of the file, download it and run sha256 on it
  4. update the file with the new value

4.2. Perl §

For perl, it is required to use a script available in the official git repository when packages are made. We will only download the latest checkout because it's quite huge.

In this example I will generate a package for Data::Traverse.

$ git clone --depth 1 https://github.com/nixos/nixpkgs
$ cd nixpkgs/maintainers/scripts
$ nix-shell -p perlPackages.{CPANPLUS,perl,GetoptLongDescriptive,LogLog4perl,Readonly}
$ ./nix-generate-from-cpan.pl Data::Traverse
attribute name: DataTraverse
module: Data::Traverse
version: 0.03
package: Data-Traverse-0.03.tar.gz (Data-Traverse-0.03, DataTraverse)
path: authors/id/F/FR/FRIEDO
downloaded to: /home/solene/.cpanplus/authors/id/F/FR/FRIEDO/Data-Traverse-0.03.tar.gz
sha-256: dd992ad968bcf698acf9fd397601ef23d73c59068a6227ba5d3055fd186af16f
unpacked to: /home/solene/.cpanplus/5.34.0/build/EB15LXwI8e/Data-Traverse-0.03
runtime deps: 
build deps: 
description: Unknown
license: unknown
License 'unknown' is ambiguous, please verify
RSS feed: https://metacpan.org/feed/distribution/Data-Traverse
===
  DataTraverse = buildPerlPackage {
    pname = "Data-Traverse";
    version = "0.03";
    src = fetchurl {
      url = "mirror://cpan/authors/id/F/FR/FRIEDO/Data-Traverse-0.03.tar.gz";
      sha256 = "dd992ad968bcf698acf9fd397601ef23d73c59068a6227ba5d3055fd186af16f";
    };
    meta = {
    };
  };

We will only reuse the part after the ===, this is nix code that defines a package named DataTraverse.

The shell definition will look like this:

with (import <nixpkgs> {});
let
  DataTraverse = buildPerlPackage {
    pname = "Data-Traverse";
    version = "0.03";
    src = fetchurl {
      url = "mirror://cpan/authors/id/F/FR/FRIEDO/Data-Traverse-0.03.tar.gz";
      sha256 = "dd992ad968bcf698acf9fd397601ef23d73c59068a6227ba5d3055fd186af16f";
    };
    meta = { };
  };

in
mkShell {
  buildInputs = [ DataTraverse perl ];
  # putting perl here is only required when not using NixOS, this tell you want Nix perl binary
}

Then, run "nix-shell myfile.nix" and run you perl script using Data::Traverse, it should work!

5. Conclusion §

Using not packaged libraries is not that bad once you understand the logic of declaring it properly as a new package that you keep locally and then hook it to your current shell session.

Finding the syntax, the logic and the method when you are not a Nix guru made me despair. I've been struggling a lot with this, trying to install from cpan or pip (even if it wouldn't work after next update of my system and I didn't even got it to work.

Benchmarking compilation time with ccache/mfs on OpenBSD

Written by Solène, on 18 September 2021.
Tags: #openbsd #benchmark

Comments on Fediverse/Mastodon

1. Introduction §

I always wondered how to make packages building faster. There are at least two easy tricks available: storing temporary data into RAM and caching build objects.

Caching build objects can be done with ccache, it will intercept cc and c++ calls (the programs compiling C/C++ files) and depending on the inputs will reuse a previously built object if available or build normally and store the result for potential next reuse. It has nearly no use when you build software only once because it requires objects to be cached before being useful. It obviously doesn't work for non C/C++ programs.

The other trick is using a temporary filesystem stored in memory (RAM), on OpenBSD we will use mfs but on Linux or FreeBSD you could use tmpfs. The difference between those two is mfs will reserve the given memory usage while tmpfs is faster and won't reserve the memory of its filesystem (which has pros and cons).

So, I decided to measure the build time of the Gemini browser Lagrange in three cases: without ccache, with ccache but first build so it doesn't have any cached objects and with ccache with objects in it. I did these three tests multiple time because I also wanted to measure the impact of using memory base filesystem or the old spinning disk drive in my computer, this made a lot of tests because I tried with ccache on mfs and package build objects (later referenced as pobj) on mfs, then one on hdd and the other on mfs and so on.

To proceed, I compiled net/lagrange using dpb after cleaning the lagrange package generated everytime. Using dpb made measurement a lot easier and the setup was reliable. It added some overhead when checking dependencies (that were already installed in the chroot) but the point was to compare the time difference between various tweaks.

2. Results numbers §

Here are the results, raw and with a graphical view. I did run multiples time the same test sometimes to see if the result dispersion was huge, but it was reliable at +/- 1 second.

Type			Duration for second build	Duration with empty cache
ccache mfs + pobj mfs	60				133
ccache mfs + pobj hdd	63				130
ccache hdd + pobj mfs	61				127
ccache hdd + pobj hdd	68				137
 no ccache + pobj mfs					124
 no ccache + pobj hdd					128
Diagram with results
Diagram with results

3. Results analysis §

At first glance, we can see that not using ccache results in builds a bit faster, so ccache definitely has a very small performance impact when there is no cached objects.

Then, we can see results are really tied together, except for the ccache and pobj both on the hdd which is the slowest combination by far compared to the others times differences.

4. Problems encountered §

My building system has 16 GB of memory and 4 cores, I want builds to be as fast as possible so I use the 4 cores, for some programs using Rust for compilation (like Firefox), more than 8 GB of memory (4x 2GB) is required because of Rust and I need to keep a lot of memory available. I tried to build it once with 10GB of mfs filesystem but when packaging it did reach the filesystem limit and fail, it also swapped during the build process.

When using a 8GB mfs for pobj, I've been hitting the limit which induced build failures, building four ports in parallel can take some disk space, especially at package time when it copies the result. It's not always easy to store everything in memory.

I decided to go with a 3 GB ccache over MFS and keep the pobj on the hdd.

I had no spare SSD to add an SSD to the list. :(

5. Conclusion §

Using mfs for at least ccache or pobj but not necessarily both is beneficial. I would recommend using ccache in mfs because the memory required to store it is only 1 or 2 GB for regular builds while storing the pobj in mfs could requires a few dozen gigabytes of memory (I think chromium requires 30 or 40 GB last time I tried).

Experimenting with a new OpenBSD development lab

Written by Solène, on 16 September 2021.
Tags: #openbsd #life

Comments on Fediverse/Mastodon

1. Experimenting §

This article is not an how to or explaining anything, I just wanted to share how I spend my current free time. It's obviously OpenBSD related.

When updating or making new packages, it's important to get the dependencies right, at least for the compilation dependencies it's not hard because you know it's fine once the building process can run entirely, but at run time you may have surprises and discover lacking dependencies.

2. What's a dependency? §

Software are made of written text called source code (or code to make it simpler), but to avoid wasting time (because writing code is hard enough already) some people write libraries which are pieces of code made in the purpose of being used by other programs (through fellow developers) to save everyone's time and efforts.

A library can propose graphics manipulation, time and date functions, sound decoding etc... and the software we are using rely on A LOT of extra code that comes from other piece of code we have to ship separately. Those are dependencies.

There are dependencies required for building a program, they are used to manipulate the source code to transform it into machine readable code, or for organizing the building process to ease the development and so on and there are libraries dependencies which are required for the software to run. The simplest one to understand would be the library to access the audio system of your operating system for an audio player.

And finally, we have run time dependencies which can be found upon loading a software or within its use. They may not be well documented in the project so we can't really know they are required until we try to use some feature of the software and it crashes / errors because of something missing. This could be a program that would call an extra program to delegate the resizing of a picture.

3. What's up? §

In order to spot these run time dependencies, I've started to use an old laptop (a thinkpad T400 that I absolutely love) with a clean OpenBSD installation, lot of local packages on my network (see it later) and a very clean X environment.

The point of this computer is to clean every package, install only one I need to try (pulling the dependencies that come with it) and see if it works under the minimal conditions. They should work with no issue if the packages are correctly done.

Once I'm satisfied with the test process, I will clean every packages on the system and try another one.

Sometimes, as we have many many packages installed, it happens we have a run time dependency installed by that is not declared in the software package we are working on, and we don't see the failure as the requirement is provided by some other package. By using a clean environment to check every single program separately, I remove the "other packages" that could provide a requirement.

4. Building §

When I work on packages I often need to compile many of them, and it takes time, a lot of time, and my laptop usually make a lot of noise and is hot and slow to do something else, it's not very practical. I'm going to setup a dedicated building machine that I will power on when I'll work on ports, and it will be hidden in some isolated corner at home building packages when I need it. That machine is a bit more powerful and will prevent my laptop to be unusable for some time.

This machine in combination with the laptop are a great combination to make quick changes and test how it goes. The laptop will pull packages directly from the building machine, and things could be fixed on the building machine quite fast.

5. The end §

Contributing to packages is an endless work, making good packages is hard work and requires tests. I'm not really good at doing packages but I want to improve myself in that field and also improve the way we can test packages are working. With these new development environments I hope I will be able to contribute a bit more to the quality of the futures OpenBSD releases.

Reviewing some open source distraction free editors

Written by Solène, on 15 September 2021.
Tags: #editors #unix

Comments on Fediverse/Mastodon

1. Introduction §

This article is about comparing "distraction free" editors running on Linux. This category of editors is supposed to be used in full screen and shouldn't display much more than text, allowing to stay focused on the text.

I've found a few programs that run on Linux and are open source, I deliberately omitted web browser based editors

  • Apostrophe
  • Focuswriter
  • Ghostwriter
  • Quilter
  • Vi (the minimal vi from busybox)

I used them on Alpine, three of them installed from Flatpak and Apostrophe installed from the Alpine packages repositories.

I'm writing this on my netbook and wanted to see if a "distraction" free editor could be valuable for me, the laptop screen and resolution are small and using it for writing seems a fun idea, although I'm not really convinced of the use (for me!) of such editors.

2. Resource usage and performance §

Quick tour of the memory usage (reported in top in the SHR column)

  • Apostrophe: 63 MB of memory
  • Focuswriter: 77 MB of memory
  • Ghostwriter: 228 MB of memory
  • Quilter: 72 MB of memory
  • vi: 0.89 MB of memory + 41 MB of memory for xfce4-terminal

As for the perceived performance when typing I've had mixed results.

  • Apostrophe: writing is smooth and pleasant
  • Focuswriter: writing is smooth and pleasant
  • Ghostwriter: writing is smooth and pleasant
  • Quilter: there is a delay when typing, I've been able to type an entire sentence and being so fast I've been able to see the last word being drawn on the screen
  • vi: writing is smooth and pleasant

3. Features §

I didn't know much what to expect from these editors, I've seen some common features and some other that I discovered.

  • focus mode: keep the current sentence/paragraph/line in focus and fade the text around
  • helpers for markdown mode: shortcuts to enable/disable bold/italic, bullet lists etc... Outlining window to see the structure of the document or also real time rendering from the markdown
  • full screen mode
  • changing fonts and display: color, fonts, background, style sheet may be customized to fit what you prefer
  • "Hemingway" mode: you can't undo what you type, I suppose it's to write as much as possible and edit later
  • Export as multiple format: html, ODT, PDF, epub...

4. Personal experience and feelings §

It would be long and not really interesting to list which program has which feature so here is my feelings about those four software.

4.1. Apostrophe §

It's the one I used for writing this article, it feels very nice, it proposes only three themes that you can't customize and the font can't be changed. Although you can't customize that much, it's the one that looks the best out of the box, that is easiest to use and which just works fine. From a distraction free editor, it seems it's the best approach.

This is the one I would recommend to anyone wanting a distraction free editor.

Apostrophe project website

4.2. Quilter §

Because of the input lag when typing text, this was the worse experience for me, maybe it's platform specific? The user interface looks a LOT like apostrophe at the point I'd think one is a fork from another, but in regards to performance it's drastically different. It offers three themes but also allow choosing the fonts from three named "Quilt something" which is disappointing.

Quilter project website

4.3. Focuswriter §

This one has potential, it has a lot of things you can tweak in the preferences menu, from which character should be doubled (like quotes) when typed, daily goals, statistics, configurable shortcuts for everything, writing from right to left.

It also relies a lot on the theming features to choose which background (picture or color) you want, how to space the text, which font, which size, opacity of the typing area. It has too many tweaks required to be usable to me, the default themes looked nice but the text was small and ugly, it was absolutely not enjoying to type and see the text appending. I tried to duplicate a theme (from the user interface) and change the font and size, but I didn't get something that I enjoyed. Maybe with some time spent it could look good, but what the other tools provide is something that just works and looks good out of the box.

Focuswriter project website

4.4. Ghostwriter §

I tried ghostwriter 1.x at first then I saw there was a 2.x version with a lot more features, so I used both for this review, I'll only cover the 2.x version but looking at the repositories information many distributions providing the old version, including flatpak.

Ghostwriter seems to be the king of the arena. It has all the features you would expect from a distraction free editor, it has sane defaults but is customizable and is enjoyable out of the box. For writing long documents, the markdown outlining panel to see the structure of the document is very useful and there are features for writing goal and statistics, this may certainly be useful for some users.

Ghostwriter project website

4.5. vi §

I couldn't review some editors without including a terminal based editor. I chose vi because it seemed the most distraction free to me, emacs has too many features and nano has too much things displayed at the bottom of the screen. I choose vi instead of ed because it's more beginner friendly, but ed would work as fine. Note that I am using vi (from busybox on Alpine linux) and not Vim or nvi.

vi doesn't have much features, it can save text to a file. The display can be customized in the terminal emulator and allow a great choice of font / theme / style / coloring after decades of refinements in this field. It has no focus mode or markdown coloration/integration, which I admit can be confusing for big texts with some markup involved, at least for bullet lists and headers. I always welcome a bit of syntactic coloration and vi lacks this (this can be solved with a more advanced text editor). vi won't allow you to export into any kind of file except plain text, so you need to know how to convert the text file into the output format you are looking for.

busybox project website

5. Conclusion §

It's hard for me to tell if typing this article using Apostrophe editor was better or more efficient than using my regular kakoune terminal text editor. The font looks absolutely better in Apostrophe but I never gave much attention to the look and feel of my terminal emulator.

I'll try using Apostrophe or Ghostwriter for further articles, at least by using my netbook as a typing machine.

Blog update 2021

Written by Solène, on 15 September 2021.
Tags: #blog #life

Comments on Fediverse/Mastodon

Hello,

This is a simple announce to gather some changes I made to my blog recently.

  • The web version of the blog now display the articles list grouped by year when viewing a tag page, previously it was displaying the whole article contents and I think tags were unusable this way, although it was so because initially I had two articles when I wrote the blog generator and it made sense.
  • The RSS file was embedding the whole HTML content of each article, I switched to use the article original plain text format, HTML should only be used in a Web browser and RSS is not meant to be dedicated for web browsers. I know this is a step back for some users but many users also appreciated this move and I'm happy to not contribute at putting HTML everywhere.
  • Most texts are now written using the gemtext format, served raw on gemini and gopher and converted into HTML for the http version using gmi2html python tool slightly modified (I forgot where I got it initially). I use gemtext because I like this format and often forced me to rethink the way I present an idea because I had to separate links and code from the content and I'm convinced it's a good thing. No more links named "here" or inlined code hard to spot.

If you think changes could be done on my blog, on the web / gopher or gemini version please share your ideas with me, it's also the opportunity for me to play with the code of the blog generator cl-yag that I absolutely love.

I have been publishing a lot more this year, I enjoy much more sharing my ideas or knowledge this way than I used to and writing is also the opportunity for me to improve my English and when I compare to the first publications I'm proud to see I improved the quality over time (I hope so at least). I got more feedback for strangers reading this blog, by mail or IRC and I'm thankful to them, they just drop by to tell me they like what I write or that I made a mistake so I can fix it, it's invaluable and allows me to make new connections to people I would never have reached otherwise.

I should try to find some time and motivation to get back at my Podcast publications now but I find it a lot harder to speak than to write some text, maybe it would be an habit to take. We will see soon.

Managing /etc/hosts on NixOS

Written by Solène, on 14 September 2021.
Tags: #nixos

Comments on Fediverse/Mastodon

1. Introduction §

This is a simple article explaining how to manage entries in /etc/hosts in a NixOS system. Modifying this file is quite useful when you need to make tests on a remote server while its domain name is still not updated so you can force a domain name to be resolved by a given IP address, bypassing DNS queries.

NixOS being what is is, you can't modify the /etc/hosts file directly.

NixOS stable documentation about the extraHosts variable

2. Configuration §

In your /etc/nixos/configuration.nix file, you have to declare the variable networking.extraHosts and use "\n" as separator for entries.

networking.extraHosts = "1.2.3.4 foobar.perso.pw\n1.2.3.5 foo.perso.pw";

or as suggested by @tokudan@chaos.social on Mastodon, you can use multiple lines in the string as follow (using two single quotes character):

networking.extraHosts = ''
1.2.3.4 foobar.perso.pw
1.2.3.5 foo.perso.pw
'';

The previous pieces of configuration will associate "foobar.perso.pw" to IP 1.2.3.4 and "foo.perso.pw" to IP 1.2.3.5.

Now, I need to rebuild my system configuration and use it, this can be done with the command nixos-rebuild switch as root.

Workaround for an OpenBSD boot error on APU boards

Written by Solène, on 10 September 2021.
Tags: #openbsd #apu

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If you ever get your hands on an APU board from PCEngines and that you have an issue like this when trying to boot OpenBSD:

Entry point at 0xffffffff8100100

There is a simple solution explained by Mischa on the misc@openbsd.org mailing list in 2020.

Re: Can't install OpenBSD 6.6 on apu4d4

I'll copy the reply here in case the archives get lost. When you get the OpenBSD boot prompt, type the following commands to tell about the serial port.

stty com0 115200
set tty com0
boot

And you are done! During the installation process you will be asked about serial devices to use but the default offered will match what you set at boot.

Dear open source developers

Written by Solène, on 09 September 2021.
Tags: #life

Comments on Fediverse/Mastodon

Dear open source and libre software developers, I would like to share thoughts with you. This could be considered as an open letter but I'm not sure to know what an open letter is, and I don't want to give instructions to anyone. I have feelings I want to share about my beloved hobby: computers and open source.

Computers are amazing, they do stuff, lot of stuff, at hardware and software level. We can use them for anything, they are a great tool and we can program our tools to match our expectations, wishes and needs, it's not easy, it's an art but also a science, we do it together because it's a huge task requiring more than one brain time to achieve.

We are currently facing supply chain issues at many levels in the electronic industry, making modern high end computers is always more complicated, we also face pollution concerns and limited resources that will prevent an infinity of computers.

I would like to see my hobby affordable for anyone. There are many many computers already built and most of their parts can be replaced which is a crazy opportunity when you compare this to the smartphone industry where no parts can be changed.

As people writing software used by others, it is absolutely important to keep old computers useful. They were useful when they were built, they should still be useful in the future to some extent.

Nowadays, a computer without network access would be considered useless but it's not. But if you want to connect a computer to the Internet, facing continuously increase of network attacks, one should only use an up to date operating system and latest software version, unfortunately it's not always easy on old computers.

Some cryptography may require regularly increased minimum requirements, this is acceptable. What is not is that doing the same task on a computer requires more resources over the years as software grows and evolves.

Nowadays, regularly, more operating systems are dropping support for older architectures to only focus on amd64. This is understandable, volunteer work is limited and it's important to focus on the hardware found in most of the users computers. But then, by doing so they are making old hardware obsolete which is not acceptable.

I understand this is a huge dilemma and I have no solution, maybe we should need less operating systems to gather the volunteers to maintain older but still relevant architectures. It is not possible obviously, volunteers work on what they want because they like it, you can't assign contributors to some task against their will.

The issue is at a higher scale and every person working in the IT field is part of the problem.

1. More ? §

Some are dropping old architectures because there are no users. There are no users because they have to replace their hardware with a more powerful new hardware to cope with software becoming more and more hungry of resources. They become so because of people writing software, because companies want to do unoptimized code to release the product with less development time implying a cheaper cost, with the trade-off of asking customers to use a more powerful computer.

The web become unusable on old hardware, you can't use the world wide web anymore on old hardware because of lack of memory, lack of javascript support or too much animations using the CPU that you can't disable.

When you think about open source systems, many think "Linux", and most people think "amd64". A big part of the open source ecosystem is now driven toward Linux/amd64 target, at the cost of all the OS / architectures that are still in use, existing, not dead.

We could argue that technology is evolving and that those should make the work to stay in the race with the holy Linux/amd64 combo, this is a receivable argument as open source can be used / forked by everyone. But it would work so much better if we worked as a whole team.

2. Thoughts §

I just wanted to express my feelings with this blog post. I don't want to tell anyone what to do, we are the open source community, we do what we enjoy.

I own old computers, from 15 years old to 8 years old, I still like to use them. Why would they be "old"? because of their date of manufacture, this is a fact. But because of the software ecosystem, they are becoming more obsolete every year and I definitely don't understand why it must be this way.

If you can give a thought to my old computers when writing code, thinking about them and make a three lines changes to improve your software for them, I would be absolutely grateful for the extra work. We don't really need more computers, we need to dig out the old computers to make them useful again.

Thank you very much dear community <3

Port of the week: pngquant

Written by Solène, on 07 September 2021.
Tags: #graphics #unix #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

Today as a "Port of the Week" article (that isn't published every week now but who cares) I would like to present you pngquant.

pngquant is a simple utility to compress png files in order to reduce them, with the goal of not altering the file in a visible way. pngquant is lossy which mean it modify the content, at the opposite of the optipng program which optimize the png file to try to reduce its size as possible without modifying the visual.

pngquant project website

2. How to use §

The easiest way to use pngquant is simply give the file to compress as an argument, a new file with the original file name with "-fs8" added before the file extension will be created.

$ pngquant file.png
$ test -f file-fs8.png && echo true
true

3. Performance §

I made a simple screenshot of four terminals on my computer, I compared the file size of the original png, the png optimized with optipng and the compressed png using pngquant. I also included a conversion to jpg of the same size as the original file.

I used defaults of each commands.

File		size (in kilobytes)	% of original (lower is better)
========	===============		===============================
original	168			100
optipng		144			85.7
pngquant	50.2			29.9
jpeg 71%	169			100

The file produced by pngquant is less than a third of the original. Here are the files so you can try to check if you see differences with the pngquant version.

4. Conclusion §

Most of the time, compressing a png is suitable for publishing or sharing. For screenshots or digital pictures, jpg format is usually very bad and is only suitable for camera pictures.

For a drawn picture you should keep the original if you ever plan to make changes on it.

Review of ElementaryOS 6 (Odin)

Written by Solène, on 06 September 2021.
Tags: #linux #review

Comments on Fediverse/Mastodon

1. Introduction §

ElementaryOS is a linux distribution based on Ubuntu that also ship with a in-house developed desktop environment Pantheon and ecosystem apps. Since their 6th release named Odin, the development team made a bold choice of proposing software through the Flatpak package manager.

I've been using this linux distribution on my powerful netbook (4 cores atom, 4 GB of memory) for some weeks, trying not to use the terminal and now this is my review.

ElementaryOS project website

ElementaryOS desktop with no window shown
ElementaryOS desktop with no window shown

2. Pantheon §

I've been using ElementaryOS a little in the past so I was already aware of the Pantheon desktop when I installed ElementaryOS Odin on my netbook, I've been pleased to see it didn't change in term of usability. Basically, Pantheon looks like a Gnome3 desktop with a nice and usable dock à la MacOS.

Using the Super key (often referred to as the "Windows key") and you will be disappointed by getting a window with a list of shortcuts that works with Pantheon. Putting the help on this button is quite clever as we are used to press it for sending commands, but after a while it's misleading to have a single button triggering help, fortunately this behaviour can be configured to display the desktop or the applications menu.

Pantheon has a very nice feature I totally love which create a floating miniature of a target window that stay on top of everything, I often need to keep an eye on a window or watch a movie, and this mode allow me to exactly do that. The miniature is easy to move on the screen, easy to resize, and upon a click the window appears and the miniature is then hidden until you switch to another window. It may seems a gadget, but on a small screens I really appreciate. You can create this for a window by pressing Super+f and clicking on a target.

Picture in picture mode, showing the AppCenter while in a terminal
Picture in picture mode, showing the AppCenter while in a terminal

The desktop comes with some programs made specifically for Pantheon: terminal emulator, file browser, text editor, calendar etc... They are simple but effective.

The whole environment is stable, good looking, coherent and usable.

3. The AppCenter and Flatpak §

As I said before, ElementaryOS is based on Ubuntu so it inherits all the packages available on Ubuntu, but they will be only installable from the command line. The Application center GUI shows an entirely different package sets that comes from the ElementaryOS flatpak repository but also the one from flathub. Official repository apps are clearly designated as official while programs from flathub will be displayed as third party and a warning about quality/security will be displayed for each program from this repository when you want to install.

Warning shown when trying to install a program from a different repository than the one from ElementaryOS
Warning shown when trying to install a program from a different repository than the one from ElementaryOS

Flatpak has a pretty bad reputation among the groups I regularly read, however I like flatpak. Crash course to flatpak: it is a Linux agnostic package manager that will not reuse your system library but instead install the whole basics dependencies required (such as X11, KDE, Gnome etc...) and then programs are installed upon this, but still separated from each other. Programs running from flatpak will have different permissions and may be limited in their permissions (no network, can only reach ~/Downloads/ etc..), this is very nice but not always convenient especially for programs that require plugins. The whole idea of flatpak is that you install a program and it shouldn't mess with the current system, and it can be installed in such way that when you use it, the person making the program bundle can restrict the permissions as much as wanted.

While installing flatpak programs take a good amount of data to download because of the big dependencies, you need them only once and updating flatpak programs will use delta changes, so only difference is downloaded, I found updates to be very small in regards to network consumption. While installing a single GUI app from flatpak on a Linux system can be seen as overkill, the small Gemini browser Lagrange involve more than 1GB of dependencies from flatpak, it totally make sense to install everything needed by the user from flatpak.

If you are unhappy with the current permissions of a program, you can use the utility Flatseal to tweak its permissions, which is very cool.

I totally understand and love the move to full flatpak, it has proven me to be solid, easy to use and easy to tweak despite flatpak still being very young. I liked very much that my Firefox on OpenBSD had the unveil feature preventing it from accessing my data in case of security breach, now with Firefox from Flatpak or Firefox run from firejail I can get the same on Linux. There is one thing I regret in the AppCenter though but this is my opinion and I can understand why it is so, some programs have a priced button like "3,00$" while the other are "Free", there is a menu near the price that let you choose the amount you want to pay but you can also put 0,00 and then the program is free. This can be misleading for users because the program is actually free but in "pay what you want" mode.

Picture of a torrent program that is not shown as free but can be set to 0,00$
Picture of a torrent program that is not shown as free but can be set to 0,00$

I have no issues paying for Free software as long as it's 100% free, but suggesting a price for a package while you don't know you can install it for free can be weird. The payment implementation of the AppCenter could be the beginning of paid software integrated into ElementaryOS, I have no strong opinion about this because people need money for a living, but I hope it will be used wisely.

4. No terminal challenge §

While trying ElementaryOS for some time, I gave myself a little challenge that was to avoid using the Terminal as much as possible. I quite succeeded as I only required a terminal to install a regular package (lutris, not available as flatpak). Of course, I couldn't prevent myself to play with a terminal to check for bandwidth or CPU usage but it doesn't count as a normal computer use.

Everything worked fine so far, network access, wireless, installing and playing video games, video players.

I'd feel confident if I recommended a non linux users to install ElementaryOS and use it. On first boot the system provides a nice introduction to explain basics.

5. Parental control §

This is a feature I'm not using but I found it in the configuration panel and I've been surprised to see it. ElementaryOS comes with a feature to restrict time in week days and week-end days, but also prevent an user to reach some URLs (no idea how this is implemented) and also forbid to run some installed Apps.

I don't have kids but I assume this can be very useful to prevent the use of the computer past some time or prevent them to use some programs, to make it work they would obviously need their own account and not able to be root. I can't judge if it works fine, if it's suitable for real world, but I wanted to share about this unique feature.

Screenshot of the parental control
Screenshot of the parental control

6. Global performance §

My netbook proved to be quite okay to use Pantheon. The worse cases I figured out are displaying the applications menu which takes a second, and the AppCenter that is slow to browse and the "searching for update" takes a long time.

As I said in the introduction, my Netbook has a quad core atom and a good amount of memory but the eMMC storage is quite slow. I don't know if the lack of responsiveness comes from my CPU or storage, but I can tell everything works smoothly on an older Core2 Duo!

7. Conclusion §

Using ElementaryOS was delightful, it just works. The team made a very good work for the whole coherence of the desktop. It is certainly not the distribution you need when you want full control or if you want something super light, but it definitely does the job for users that just want things to work, and who like Pantheon. It doesn't seem straightforward to switch to another desktop environment.

Playing with a new shell: fish

Written by Solène, on 05 September 2021.
Tags: #openbsd #shell

Comments on Fediverse/Mastodon

1. Introduction §

Today I'll introduce you to the interactive shell fish. Usually, Linux distributions ships bash (which can be a hidden dash, a limited shell), MacOS is providing zsh and OpenBSD ksh. There are other shells around and fish is one of them.

But fish is not like the others.

fish shell project website

2. What make it special? §

Here is a list of biggest changes:

  • suggested input based on commands available
  • suggested input based on history (even related to the current directory you are in!)
  • not POSIX compatible (the usual shell syntax won't work)
  • command completion works out of the box (no need for extensions like "ohmyzsh")
  • interconnected processes: updating a variable can be done into every opened shells

Asciinema recording showing history features and also fzf integration

3. Making history more powerful with fzf §

fzf is a simple utility for searching data among a file (the history file in that case) in fuzzy mode, meaning in not a strict matching, on OpenBSD I use the following configuration file in ~/.config/fish/config.fish to make fzf active.

When pressing ctrl+r with some history available, you can type any words you can think about an old command like "ssh bar" and it should return "ssh foobar" if it exists.

source /usr/local/share/fish/functions/fzf-key-bindings.fish
fzf_key_bindings

fzf is absolutely not related to fish, it can certainly be used in some other shells.

github: fzf project

4. Tips §

4.1. Disable caret character for redirecting to stderr §

The defaults works pretty well but as I said before, fish is not POSIX compatible, meaning some habits must be changed. By default, ^ character like in "grep ^foobar" is the equivalent of 2> which is very misleading.

# make typing ^ actually inserting a "^" and not stderr redirect
set -U fish_features stderr-nocaret qmark-noglob

4.2. Web GUI for customizing your shell §

If you want to change behaviors or colors of your shell, just type "fish_config" while in a shell fish, it will run a local web server and open your web browser.

4.3. Validating a suggestion §

When you type a command and you see more text suggested as you type the command you can press ctrl+e to validate the suggestion. If you don't care about the suggestion, continue typing your command.

4.4. Get the return value of latest command §

In fish, you want to read $status and not $? , that variable doesn't exist in fish.

4.5. Syntax changes §

Because it's not always easy to find what changed and how, here is a simple reminder that should cover most of your needs:

  • loops (no do keyword, ends with end): for i in 1 2 3 ; echo $i ; end
  • condition (no then, ends with end): if something ; echo true ; end
  • inline command (no dollar sign): (date +%s)
  • export a variable: set -x EDITOR kak
  • return value of last command: $status

5. Conclusion §

I love this shell. I've been using the shell that come with my system since forever, and a few months ago I wanted to try something different, it felt weird at first but over time I found it very convenient, especially for git commands or daily tasks, suggesting me exactly the command I wanted to type in that exact directory.

Obviously, as the usual syntax changes, it may not please everyone and it's totally fine.

External GPU on Linux review

Written by Solène, on 01 September 2021.
Tags: #linux #gentoo #games #egpu

Comments on Fediverse/Mastodon

1. Introduction §

I like playing video games, and most games I play require a GPU that is more powerful than the integrated graphic chipset that can be found in laptop or computers. I recently found that external graphic card were a thing, and fortunately I had a few spare old graphic card for trying.

The hardware is called an eGPU (for external GPU) and are connected to the computer using a thunderbolt link. Because I buy most of my hardware second hand now, I've been able to find a Razer Core X eGPU (the simple core X and not the core X Chroma which provides USB and RJ45 connectivity on the case through thunderbolt), exactly what I was looking for. Basically, it's an external case with a PSU inside and a rack, pull out the rack and insert the graphic card, and you are done. Obviously, it works fine on Windows or Mac but it can be tricky on Linux.

Razer core X product

Attempt to make a picture of my eGPU with an nvidia 1060 in it
Attempt to make a picture of my eGPU with an nvidia 1060 in it

2. My setup §

I'm using a Lenovo T470 with an i5 CPU. When I want to use the eGPU, I connect the thunderbolt wire and keyboard / mouse (which I connect through an USB KVM to switch those from a computer to another). The thunderbolt port also provide power to the laptop which is good to know.

3. How does it work? §

There are two ways to use this device, the display can be connected to the eGPU itself or the rendering could be done on the laptop (let's say we only target laptops here) using the eGPU as a discrete card (only rendering, without display). Both modes have pros and cons.

  • External display Pros: best performance, allow many displays to be used
  • External display Cons: require a screen
  • Discrete mode Pros: no extra wire, no different setup when using the laptop without the eGPU
  • Discrete mode Cons: performance penalty, support doesn't work well on Linux

The performance penalty comes from the fact the thunderbolt bandwidth is limited, and if you want to display on your screen you need to receive the data back which will reduce the bandwidth allowed for rendering. A penalty of at least 20% should be expected in normal mode, and around 40% in discrete mode. This is not really fun but for a nice boost with an old graphic card this is still nice.

eGPU on Linux with a Razer core X Chroma

eGPU benchmarks

4. Configuration (NVIDIA) §

It's quite simple now in 2023 (blog update), the first step is to install nvidia-drivers.

4.1. Discrete mode §

- Add your user to the video group (at least on Gentoo)

- No /etc/X11/xorg.conf file is required

- The graphical card should appear in nvidia-settings under a "PRIME" menu

- Use prime-run as a prefix to run commands, the discrete mode is simply enabled by environment variables. If prime-run isn't a thing in your distribution, create a script nvidia-offload like explained in the NixOS wiki

NixOS wiki: Nvidia - offload mode

If you want to run Flatpak programs with the discrete GPU, you will need to set all the environment variables in the flatpak program environment. You can't just set them in your shell and run flatpak from there because of the sandboxing.

4.2. External display §

- Run nvidia-xconfig to create a /etc/X11/xorg.conf file that uses the Nvidia card as the main display

4.3. Both mode §

I ended figuring a xorg.conf allowing me to keep the same file with and without the eGPU, and to use the discrete and external display at the same time. The funniest part is if you run a program on the nvidia screen and move it back to the laptop screen, the eGPU continues to render it.

It's by far the most convenient configuration as you have nothing to tweak, and you can use laptop + eGPU displays.

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "intel"
    Inactive "nvidia"
    Option "AllowNVIDIAGPUScreens"
EndSection

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID  "PCI:0:2:0"
EndSection

Section "Screen"
    Identifier "intel"
    Device "intel"
EndSection

Section "Device"
    Identifier "nvidia"
    Driver "nvidia"
    BusID  "PCI:10:0:0"
    Option "AllowExternalGpus" "True"
EndSection

Section "Screen"
    Identifier "nvidia"
    Device "nvidia"
EndSection

4.4. Switching between modes §

If you want to switch from one to the other, you need to exit all X servers first. Booting with a xorg.conf for Nvidia while not having a Nvidia card plugged in will prevent X to start, which is annoying.

The program egpu-switch can help in that regard, but it can't choose between discrete or external display mode, you will need to decide which mode you prefer when the card is plugged by providing the according xorg.conf file.

egpu-switcher GitHub project page

5. What to expect of it on Linux? §

I've been using this on Gentoo only so far, but I had a previous experience with a pretty similar setup a few years ago with a laptop with a discrete nvidia card (called Optimus at that time), and the GPU was only usable as a discrete GPU and it was a mess at that time.

As for the eGPU, in external mode it works fine using the nvidia driver, I needed an xorg.conf file to tell to use the nvidia driver, then the display would be fine and 3D would work perfectly as if I was using a "real" card on a computer. I can play high demanding games such as Control, Death Stranding or other games using my Thinkpad Laptop when docked, this is really nice!

The setup is a bit weird though, if I want to undock, I need to prepare the new xorg.conf file and stop X, disconnect the eGPU and restart the display manager to login. Not very easy. I've been able to script it using a simple script at boot that will detect the Nvidia GPU and choose the correct xorg.conf file just before starting the display manager, it works quite fine and makes life easier.

6. Video games? §

I've been playing Steam video games, it works absolutely perfectly due to their work on Proton to make Windows games running. GOG games works fine too, I use Lutris games library manager to handle them and it works so far.

Now, there is the tricky discrete mode. On linux, the bumblebee project allows rendering a program in a virtual display to benefit from the 3D acceleration and then show it on another device, this work was done for Optimus hardware hence the bumblebee name (related to Transfomers lore). Steam doesn't like bumblebee at all and won't start game, this is a known bug, Steam is bad at managing multiple GPUs. I've not been able to display anything using bumblebee.

On the other hand, native Linux GOG games were working fine using bumblebee, however I don't own much high demanding Linux games so I've not been able to see if the performance hit was hard. Windows GOG games wouldn't run, partially because the DXVK (directX to vulkan) Wine rendering can't be used because bumblebee doesn't allow using Vulkan graphical API and error messages were unhelpful. I have literally lost two days of my life trying to achieve something useful with the discrete GPU mode but nothing came out of it, except native Linux games.

Playing Control on Gentoo (windowed for the screen)
Playing Control on Gentoo (windowed for the screen)

7. Why using an eGPU? §

Laptops are very limited in their upgrade capabilities, adding a GPU could avoid someone to own a "gaming" tower PC and a good laptop. The GPU is 100% replaceable because the case offers a pci express port and a standard PSU (which can be replaced too!). The EGPU could be shared among a few users in a home too. This is a nice way to recycling old GPUs for a nice graphic boost to play everything that is more than 5 years old (and that's a bunch of good games!). I think using a top notch GPU in this would be a waste though.

8. Conclusion §

I'm pretty happy with the experience so far, now I can play my favorites games on Linux using the same computer I like to use all the day. While the experience is not as plug and play than it is on Windows, it is solid and stable.

9. Troubleshoot §

Some reminders when something is wrong.

9.1. OpenSUSE setup §

This distribution ships with a tool "prime-select" which is very convenient, you can pick which driver you want to enable first, or if you want to do discrete rendering.

9.2. No sound §

An udev rule is certainly blocking the audio device for some reasons... On a system, I found the file "/lib/udev/rules.d/90-nvidia-udev-pm-G05.rules" with a comment about disabling audio devices, commenting it solves the problem.

Fair Internet bandwidth management on a network using OpenBSD

Written by Solène, on 30 August 2021.
Tags: #openbsd #bandwidth

Comments on Fediverse/Mastodon

1. Introduction §

I have a simple DSL line with a 15 Mb/s download and 900 kb/s upload rates and there are many devices using the Internet and two people in remote work. Some poorly designed software (mostly on windows) will auto update without allowing to reduce the bandwidth or some huge bloated website will require lot of download and will impact workers using the network.

The point of this article is to explain how to use OpenBSD as a router on your network to allow the Internet access to be used fairly by devices on the network to guarantee everyone they will have at least a bit of Internet to continue working flawlessly.

I will use the queuing features from the OpenBSD firewall PF (Packet Filter) which relies on the CoDel network scheduler algorithm, which seems to bring all the features we need to do what we want.

pf.conf manual page: QUEUEING section

Wikipedia page about the CoDel network scheduler algorithm

2. Important §

I'm writing this in a separate section of the article because it is important to understand.

It is not possible to limit the download bandwidth, because once the data are already in the router, this mean they came from the modem and it's too late to try to do anything. But there is still hope, if the router receives data from the Internet it's that some devices on the network asked to receive it, you can act on the uploaded data to throttle what we receive. This is not obvious at first but it makes totally sense once you get the idea.

The biggest point to understand is that you can throttle download speed through the ACK packets. Think of two people on a phone, let's say Alice and Bob, Alice is your network and calls Bob who is very happy to tell his life to Alice. Bob speaking is data you download. In a normal conversation, Bob will talk and will hear some sounds from Alice who acknowledge what Bob is saying. If Alice stops or shut her microphone, Bob may ask if Alice is still listening and will wait for an answer. When Alice is making a sound (like "hmmhm or yes"), this is an acknowledgement for Bob to continue. Literally, Bob is sending a voice stream to Alice who is sending ACK (acknowledgement short name) packets to Bob so he can continue.

This is exactly where you can control bandwidth, if we reduce the bandwidth used by ACK packets for a download, you can reduce the given download. If you can allow multiple systems to fairly send their share of ACK, they should have a fair share of the downloaded data.

What's even more important is that you absolutely don't use all the upload bandwidth with ACK packets to reach your maximum download bandwidth. We will have to separate ACK from uploaded data so we don't limit file upload or similar flows.

3. Setup §

For the setup I used a laptop with two network cards, one was connected to the ISP box and the other was on the LAN side. I've enabled a DHCP server on the OpenBSD router to automatically give IP addresses and gateway and name servers addresses to devices on the network.

Basically, you can just plug an equivalent router on your current LAN, disable DHCP on your ISP router and enable DHCP on your OpenBSD system using a different subnet, both subnets will be available on the network but for tests it requires little changes, when you want to switch from a router to another by default, toggle the DHCP service on both and renew DHCP leases on your devices. This is extremely easy.


  +---------+
  |  ISP    |
  |  router |
  +---------+
       |
       |
       | re0
  +---------+
  | OpenBSD |
  | router  |
  +---------+
       | em0
       | 
       |
  +---------+
  | network |
  | switch  |
  +---------+

4. Configuration explained §

4.1. Line by line §

I'll explain first all the config lines from my /etc/pf.conf file, and later in this article you will find a block with the complete rules set.

The following lines are default and can be kept as-is except if you want to filter what's going in or out, but it's another topic as we only want to apply queues. Filtering would be as usual.

set skip on lo

block return	# block stateless traffic
pass		# establish keep-state

This is where it get interesting. The upstream router is accessed through the interface re0, so we create a queue of the speed of the link of that interface, which is 1 Gb/s. pf.conf syntax requires to use bits per second (b/s or bps) and not bytes per second (Bps or B/s) which can be misleading.

queue std on re0 bandwidth 1G

Then, we create a queue that inherits from the parent created before, this represent the whole upload bandwidth to reach the Internet. We will make all the traffic reaching the Internet to go through this queue.

I've set a bandwidth of 900K with a max of 900K, this mean, that this queue can't let pass more than 900 kilo bits per second (which represent 900/8 = 112.5 kB/s or kilo Bytes per second). This is the extreme maximum my Internet access allows me.

	queue internet parent std bandwidth 900K max 900K

The following lines are all sub queues to divide the upload usage, we want to have a separate queue for DNS request which must not be delayed to keep responsiveness, but also voip or VPN queues to guarantee a minimum available for the users.

The web queue is the one which is likely to pass the most data, if you upload a file through a website, it will pass through the web queue. The unknown queue is the outgoing traffic that is not known, it's up to you to put a maximum or not.

Finally, the ackp queue that is split into two other queues, it's the most important part of the setup.

The "bandwidth xxxK" values should sum up to something around the 900K defined as a maximum in the parent, this only mean we target to keep this amount for this queue, this doesn't enforce a minimum or a maximum which can be defined with min and max keywords.

As explained earlier, you can control the downloading speed by regulating the sent ACK packets, all ACK will go through the queues ack_web and ack.

ack_web is a queue dedicated for http/https downloads and the other ack queue is used for other protocol, I preferred to divide it in two so other protocol will have a bit more room for themselves to counterbalance a huge http download (Steam game platform like to make things hard on this topic by making downloads to simultaneous server for maximum bandwidth usage).

The two ack queues accumulated can't get over the parent queue set as 406K here. Finding the correct value is empirical, I'll explain later.

All these queues created will allow each queue to guarantee a minimum from the router point of view, roughly said per protocol here. Unfortunately, this won't guarantee computers on the network will have a fair share of the queues! This is a crucial understanding I lacked at first when trying to do this a few years ago. The solution is to use the "flow" scheduler by using the flow keyword in the queue, this will give some slot to every session on the network, guarantying (at least theoretically) every session have the same time passed to send data.

I used "flows" only for ACK, it proved to work perfectly fine for me as it's the most critical part but in fact, it could be applied to every leaf queues.

		queue web      parent internet bandwidth 220K qlimit 100
		queue dns      parent internet bandwidth   5K
		queue unknown  parent internet bandwidth 150K min 100K qlimit 150 default
                queue vpn      parent internet bandwidth 150K min 200K qlimit 100
                queue voip     parent internet bandwidth 150K min 150K
                queue ping     parent internet bandwidth  10K min  10K
                
		queue ackp     parent internet bandwidth 200K max 406K
			queue ack_web parent ackp bandwidth 200K flows 256
			queue ack     parent ackp bandwidth 200K flows 256

Because packets aren't magically assigned to queues, we need some match rules for the job. You may notice the notation with parenthesis, this mean the second member of the parenthesis is the queue dedicated for ACK packets.

The VOIP queuing is done a bit wide, it seems Microsoft Teams and Discord VOIP goes through these port ranges, it worked fine from my experience but may depend of protocols.

match proto tcp from em0:network to any queue (unknown,ack)
match proto tcp from em0:network to any port { 80 443 8008 8080 } queue (web,ack_web)
match proto tcp from em0:network to any port { 53 } queue (dns,ack)
match proto udp from em0:network to any port { 53 } queue dns

# VPN (wireguard, ssh, openvpn)
match proto udp from em0:network to any port { 4443 1194 } queue vpn
match proto tcp from em0:network to any port { 1194 22 } queue (vpn,ack)

# voip (teams)
match proto tcp from em0:network to any port { 3479 50000:50060 } queue voip
match proto udp from em0:network to any port { 3479 50000:50060 } queue voip

# keep some bandwidth for ping packets
match proto icmp from em0:network to any queue ping

Simple rule to enable NAT so devices from the LAN network can reach the Internet.

# NAT to the outside
pass out on egress from !(egress:network) nat-to (egress)

Default OpenBSD rules that can be kept here.

# By default, do not permit remote connections to X11
block return in on ! lo0 proto tcp to port 6000:6010

# Port build user does not need network
block return out log proto {tcp udp} user _pbuild

4.2. How to choose values §

In the previous section I used absolute values, like 900K or even 406K. A simple way to define them is to upload a big file to the Internet and check the upload rate, I use bwm-ng but vnstat or even netstat (with the correct combination of flags) could work, see your average bandwidth over 10 or 20 seconds while transferring, and use that value as a maximum in BITS as a maximum for the internet queue.

As for the ACK queue, it's a bit more tricky and you may tweak it a lot, this is a balance between full download mode or conservative download speed. I've lost a bit of download rate for the benefit of keeping room for more overall responsiveness. Like previously, monitor your upload rate when you download a big file (or even multiples files to be sure to fill your download link) and you will see how much will be used for ACK. It will certainly be a few try and guesses before you get the perfect value, too low and the maximum download rate will be reduced, and too high and your link will be filled entirely when downloading.

4.3. Full configuration §

set skip on lo

block return	# block stateless traffic
pass		# establish keep-state

queue std on re0 bandwidth 1G
	queue internet parent std bandwidth 900K min 900K max 900K
		queue web  parent internet bandwidth 220K qlimit 100
		queue dns  parent internet bandwidth   5K
		queue unknown  parent internet bandwidth 150K min 100K qlimit 120 default
                queue vpn  parent internet bandwidth 150K min 200K qlimit 100
                queue voip parent internet bandwidth 150K min 150K
                queue ping parent internet bandwidth 10K min 10K
		queue ackp parent internet bandwidth 200K max 406K
			queue ack_web parent ackp bandwidth 200K flows 256
			queue ack     parent ackp bandwidth 200K flows 256

match proto tcp from em0:network to any queue (unknown,ack)
match proto tcp from em0:network to any port { 80 443 8008 8080 } queue (web,ack_web)
match proto tcp from em0:network to any port { 53 } queue (dns,ack)
match proto udp from em0:network to any port { 53 } queue dns

# VPN (ssh, wireguard, openvpn)
match proto udp from em0:network to any port { 4443 1194 } queue vpn
match proto tcp from em0:network to any port { 1194 22 } queue (vpn,ack)

# voip (teams)
match proto tcp from em0:network to any port { 3479 50000:50060 } queue voip
match proto udp from em0:network to any port { 3479 50000:50060 } queue voip

# ICMP
match proto icmp from em0:network to any queue ping

# NAT
pass out on egress from !(egress:network) nat-to (egress)

# default OpenBSD rules
# By default, do not permit remote connections to X11
block return in on ! lo0 proto tcp to port 6000:6010

# Port build user does not need network
block return out log proto {tcp udp} user _pbuild

5. How to monitor §

There is an excellent tool to monitor the queues in OpenBSD which is systat in its queue view. Simply call it with "systat queue", you can define the refresh rate by pressing "s" and a number. If you see packets being dropped in a queue, you can try to increase the qlimit of the queue which is the amount of packets kept in the queue and delayed (it's a FIFO) before dropping them. The default qlimit is 50 and may be too low.

systat man page anchored to the queues parameter

6. Conclusion §

I've spent a week scrutinizing pf.conf manual and doing many tests with many hardware until I understand that ACK were the key and that the flow queuing mode was what I was looking for. As a result, my network is much more responsive and still usable even when someone/some device is using the network without any kind of limit.

The setup can appear a bit complicated but in the end it's only a few pf.conf lines and using the correct values for your internet access. I chose to make a lot of queues, but simply separating ack from the default queue may be enough.

pkgupdate, an OpenBSD script to update packages fast

Written by Solène, on 15 August 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

pkgupdate is a simple shell script meant for OpenBSD users of the stable branchs (people following releases) to easily keep their packages up to date.

It is meant to be run daily by cron on servers on at boot time for workstations (you can obviously configure it how you prefer).

pkgupdate git repository (web view)

2. Why ? How ? §

Basically, I've explained all of this in the project repository README file.

I strongly think updating packages at boot time is important for workstation users, so the process has to be done fast and efficiently, without requiring user agreement (by setting this up, the sysadmin agreed).

As for servers, it could be useful to by running this a few time a day and using checkrestart program to notify the admin if some process is required to restart after an update.

3. Whole setup §

Too long, didn't read? Here the code to make the thing up!

$ su -
# git clone https://tildegit.org/solene/pkgupdate.git
# cp pkgupdate/pkgupdate /usr/local/bin/
# crontab -e (which will open EDITOR, add the following lines)

### BEGIN this goes into crontab
# for updating on boot
@reboot /usr/local/bin/pkgupdate
### END of this goes into crontab

Faster packages updates with OpenBSD

Written by Solène, on 06 August 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

On OpenBSD, pkg_add is not the fastest package manager around but it is possible to make a simple change to make yours regular updates check faster.

Disclaimer: THIS DOES NOT WORK ON -current/development version!

2. Explanation §

When you configure the mirror url in /etc/installurl, on release/stable installations when you use "pkg_add", some magic happens to expand the base url into full paths usable by PKG_PATH.

http://ftp.fr.openbsd.org/pub/OpenBSD

becomes

http://ftp.fr.openbsd.org/pub/OpenBSD/%v/packages-stable/%a/:http://ftp.fr.openbsd.org/pub/OpenBSD/%v/packages/%a/

The built string passed to PKG_PATH is the concatenation (joined by a ":" character) of the URL toward /packages/ and /packages-stable/ directories for your OpenBSD version and architecture.

This is why when you use "pkg_info -Q foobar" to search for a package and that a package name matches "foobar" in /packages-stable/ pkg_info will stop, it search for a result in the first URL given by PKG_PATH, when you add -a like "pkg_info -aQ foobar", it will look in all URL available in PKG_PATH.

3. Why we can remove /packages/ §

When you run your OpenBSD system freshly installed or after an upgrade, when you have your packages sets installed from the repository of your version, the files in /packages/ in the mirrors will NEVER CHANGE. When you run "pkg_add -u", it's absolutely 100% sure nothing changed in the directory /packages/, so checking for changes against them every time make no sense.

Using "pkg_add -u" with the defaults makes sense when you upgrade from a previous OpenBSD version because you need to upgrade all your packages. But then, when you look for security updates, you only need to check against /packages-stable/.

4. How to proceed §

There are two ways, one reusing your /etc/installurl file and the other is hard coding it. Pick the one you prefer.

# reusing the content of /etc/installurl
env PKG_PATH="$(cat /etc/installurl)/%v/packages-stable/%a/" pkg_add -u

# hard coding the url
env PKG_PATH="http://ftp.fr.openbsd.org/pub/OpenBSD/%v/packages-stable/%a/" pkg_add -u

Be careful, you will certainly have a message like this:

Couldn't find updates for ImageMagick-6.9.12.2 adwaita-icon-theme-3.38.0 aom-2.0.2 argon2-20190702 aspell-0.60.6.1p10 .....

This is perfectly normal, as pkg_add didn't find the packages in /packages-stable/ it wasn't able to find the current version installed or an update, as we only want updates it's fine.

5. Simple benchmark §

On my server running 6.9 with 438 packages I get these results.

  • packages-stable only: 44 seconds
  • all the packages: 203 seconds

I didn't measure the bandwidth usage but it should scale with the time reduction.

6. Conclusion §

This is a very simple and reliable way to reduce the time and bandwidth required to check for updates on OpenBSD (non -current!). I wonder if this would be a good idea to provide it as a flag for pkg_add, like "only check for stable updates".

Register multiples wifi networks on OpenBSD

Written by Solène, on 05 August 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

This is a short text to introduce you about an OpenBSD feature arrived in 2018 and that may not be known by everyone. Wifi interfaces can have a list of network and their associated passphrase to automatically connect when network is known.

phessler@ hackathon report including wifi join feature

2. How to configure §

The relevant configuration information is in the ifconfig man page, look for "WIRELESS DEVICES" and check the "join" keyword.

OpenBSD ifconfig man page anchored on the join keyword

OpenBSD FAQ about wireless LAN

Basically, in your /etc/hostname.if file (if being replaced by the interface name like iwm0, athn0 etc...), list every access point you know and their according password.

join android_hotspot wpakey t00345Y4Y0U
join my-home wpakey goodbyekitty
join friends1 wpakey ilikeb33r5
join favorite-bar-hotspot

This will make the wifi interface to try to connect to the first declared network in the file if multiples access points are available. You can temporarily remove a hotspot from the list using "ifconfig iwm0 -join android_hotspot" if you don't want to connect to it.

Automatically lock screen on OpenBSD using xidle and xlock

Written by Solène, on 30 July 2021.
Tags: #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

For security reasons I like when my computer screen get locked when I'm away and forgot to lock it manually or when I suspend the computer. Those operations are usually native in desktop managers such as Xfce, MATE or Gnome but not when you use a simple window manager.

Yesterday, I was looking at the xlock man page and found recommendations to use it with xidle, a program that triggers a command when we don't use a computer. That was the match I required to do something.

2. xidle §

xidle is simple, you tell it about conditions and it will run a command. Basically, it has three triggers:

  • no activity from the user after $TIMEOUT
  • cursor is moved in a screen border or corner for $SECONDS
  • xidle receives a SIGUSR1 signal

The first trigger is useful for automatic run, usually when you leave the computer and you forget to lock. The second one is a simple way to trigger your command manually by moving the cursor at the right place, and finally the last one is the way to script the trigger.

xidle man page, EXAMPLES section showing how to use it with xlock

xlock man page

3. Using both §

Reusing the example given in xidle it was easy to build the command line. You would have to use this in your ~/.xsession file that contain instructions to run your graphical session. The following command will lock the screen if you let your mouse cursor in the upper left corner of the screen for 5 seconds or if you are inactive for 1800 seconds (30 minutes), once the screen is locked by xlock, it will turn off the display after 5 seconds. It is critical to run this command in background using "&" so the xsession script can continue.

xidle -delay 5 -nw -program "/usr/X11R6/bin/xlock -dpmsstandby 5" -timeout 1800 &

4. Resume / Suspend case §

So, we currently made your computer auto locking after some time when you are not using it, but what if you put your computer on suspend and leave, this mean anyone can open it and it won't be locked. We should trigger the command just before suspending the device, so it will be locked upon resume.

This operation is possible by giving a SIGUSR1 to xidle at the right time, and apmd (the power management daemon on OpenBSD) is able to execute scripts when suspending (and not only).

apmd man page, FILES section about the supported operations running scripts

Create the directory /etc/apm/ and write /etc/apm/suspend with this content:

#!/bin/sh

pkill -USR1 xidle

Make the script executable with chmod +x /etc/apm/suspend and restart apmd. Now, you should have the screen getting locked when you suspend your computer, automatically.

5. Conclusion §

Locking access to a computer is very important because most of the time we have programs opened, security keys unlocked (ssh, gpg, password managers etc...) and if someone put their hands on it they can access all files. Locking the screen is a simple but very effective way to prevent this disaster to happen.

Studying the impact of being on Hacker News first page

Written by Solène, on 27 July 2021.
Tags: #networking #openbsd #blog

Comments on Fediverse/Mastodon

1. Introduction §

Since beginning of 2021, my blog has been popular a few times on the website Hacker News and it draws a lot of traffic. This is a report of the traffic generated by Hacker News because I found this topic quite interesting.

Hacker News website: a portal where people give interesting URL and members can vote/comment the link

2. Data §

From data gathered from the http server access logs, my blog has an average of 1200 visitors and 1100 hits every day.

The blog was featured on hacker news: 16th February, 10th May, 7th July and 24th July. On the following diagram, you can see each spike being an appearance on hacker news.

What's really interesting, is the different between 24th July and the other spikes, only 24th July appearance made up to the front page of hacker news. That day, the server received 36 000 visitors and 132 000 hits and it continued the next date at a slower rate but still a lot more noticeable than other spikes.

Visitors/Hits of the blog (generated using goaccess)
Visitors/Hits of the blog (generated using goaccess)

The following diagram comes from the tool pfstat, gathering data from the OpenBSD firewall to produce images. We can see the firewall is usually at a rate of ~35 new TCP states per seconds, on 24th July, it drastically increased very fast to 230 states per second for at least 12h and the load continued for days compared to the usual traffic.

Firewall states per second
Firewall states per second

3. Conclusion §

I don't have much more data than this, but it's already interesting to see the insane traffic drag and audience that Hacker News can generate. Having a static website and enough bandwidth didn't made it hard to absorb the load, but if you have a dynamic website running code, you could be worried to be featured on Hacker News which would certainly trigger a denial of service.

Wikipedia article on the "Slashdot effect" explaining this phenomena

The Old Computer Challenge: 10 days later, what changed?

Written by Solène, on 26 July 2021.
Tags: #openbsd #life #oldcomputerchallenge

Comments on Fediverse/Mastodon

1. Introduction §

Ten days ago I finished the Old Computer Challenge I started, it gather a dozen of people over the days and we had a great week of fun restricting ourselves with a 1 CPU / 512 MB old computer and try to manage our daily tasks using it.

In my last article about it, I noticed many things about my computer use and reported them. Did it change my habits?

2. How it changed me §

Because I noticed using an old computer improved my life because I was using it less made me realize it was all about self discipline.

2.1. Checking news once a day is enough §

I have accounts on some specialized news website (bike, video games) and I used to check them every too often when I was clueless about what to do. I'm trying to reduce the number of time I look for news there, if I miss a news I can still read it the next day. I'm also more looking into RSS feed when available so I can just stop visiting the website entirely.

2.2. Forums with low traffic §

Same as for news, I only look a few time in the day the forums I participate to check for replies or new message, instead of every 10 minutes.

2.3. Shutdown instead of suspend §

I started to shutdown my computer at evening after my news routine check. If nothing had to be done on the computer, I find it better to shutdown it so I'm not tempting to reuse it. I was using suspend/resume before and it was too easy to just resume the computer to look for a new IRC message. I realized IRC messages can wait.

2.4. Read NOW §

A biggest change on the old computer was that when browsing the internet and blogs, I was actually reading the content instead of bookmarking it and never come back or reading the text very fast by looking for some key word to have some vague idea of the text.

On my laptop, when reading content in Firefox, I find it very hard to focus on text, maybe because of the font, the size, the spacing, the screen contrast, I don't know. Using the Reader mode in Firefox drastically helps me focusing on the text. When land on a page with some interesting text, I switch to reader me and read it. HUGE WIN for me here.

I really don't know why I find text easier to read in w3m, I should try it on my computer but it's quite a pain to reach a page on some websites, maybe I should try to open w3m to read content I want after I find it using Firefox.

2.5. Slow is slow §

Sometimes I found my OpenBSD computer to be slow, using a very old computer helped me put it into perspective. Using my time more efficiently with less task switching doesn't require as much as performance as one would think.

2.6. Driving development ideas §

I recently wrote the software "potcasse" to manage podcasts distribution, I came to it thinking I want to record my podcasts and publish them from the old computer, I needed a simple and fast method to use it on that old system.

3. Conclusion §

The challenge was not always easy but it has bring a lot of fun for a week and in the end, it changed the way I use computer now. No regret!

OpenBSD full Tor setup

Written by Solène, on 25 July 2021.
Tags: #openbsd #tor #privacy #security

Comments on Fediverse/Mastodon

1. Introduction §

If for some reasons you want to block all your traffic except traffic going through Tor, here is how to proceed on OpenBSD.

The setup is simple and consists at installing Tor, running the service and configure the firewall to block every requests that doesn't come from the user _tor used by Tor daemon.

2. Setup §

Modify /etc/pf.conf to make it look like the following:

set skip on lo

# block OUT traffic
block out

# block IN traffic and allow response to our OUT requests
block return

# allow TCP requests made by _tor user
pass out on egress proto tcp user _tor

If you forgot to save your pf.conf file, the default file is available in /etc/examples/pf.conf if you want to go back to a standard PF configuration.

Here are the commands to type as root to install tor and reload PF:

pkg_add tor
rcctl enable tor
rcctl start tor
pfctl -f /etc/pf.conf

Configure your programs to use the proxy SOCKS5 localhost:9050, if you need to reach a remote server / service of yours, you will need to have a server running tor and define HiddenServices to access them through Tor.

3. Privacy considerations in the local area network §

Please consider that if you are using DHCP to obtain an IP on the network the hostname of your system is shared and also its MAC address.

As for the MAC address, you can use "lladdr random" in your interface configuration file to have a new random MAC address on every boot.

As for the hostname, I didn't test it but it should work, rewrite your /etc/myname file with a new value at each boot, meaning the next boot you will have a new value. To do so, you could run an /etc/rc.local with this script:

#!/bin/sh

grep -v ^# /usr/share/misc/airport | cut -d ':' -f 1 | sort -R | head -n 1 > /etc/myname

The script will take a random name out of the 2000+ entries of the airport list (every airport in the list has been visited by OpenBSD developed before it is added). This still mean you have 1/2000 chance to have the same name upon reboot, if you prefer more entropy you can make a script generating a long random string.

4. Privacy considerations on the Web §

You shouldn't use Tor for anything, this may leak your IP address depending on the software used, it may not be built with privacy in mind. The Tor Browser (modified Firefox including Tor and privacy settings) can be fully trusted to only share/send what is required and not more.

The point of this setup is to block leaking programs and only allow Tor to reach the Internet, then it's up to you to use Tor wisely. I recommend reading Tor documentation to understand how it works.

Tor project documentation

5. Potential issues §

The only issue I can imagine right now is connecting on a network with a captive portal to reach the Internet, you would have to disable the PF rule (or entire PF) at the risk of some programs leaking data.

6. Same setup with I2P §

If you prefer using i2p only to reach external services, replace _tor by _i2p or _i2pd in the pf.conf rule, depending on which implementation you used.

7. Conclusion §

I'm not a huge Tor user but for the people who need to be sure non-Tor traffic can't go out, this is a simple setup to make.

Why self hosting is important

Written by Solène, on 23 July 2021.
Tags: #fediverse #selfhosting #chatons #life #internet

Comments on Fediverse/Mastodon

1. Introduction §

Computers are amazing tools and Internet is an amazing network, we can share everything we want with anyone connected. As for now, most of the Internet is neutral, meaning ISP have to give access to the Internet to their customer and don't make choices depending on the destination (like faster access for some websites).

This is important to understand, this mean you can have your own website, your own chat server or your own gaming server hosted at home or on a dedicated server you rent, this is called self hosting. I suppose putting the label self hosting on dedicated server may not make everyone agree, this is true it's a grey area. The opposite of self hosting is to rely on a company to do the job for you, under their conditions, free or not.

2. Why is self hosting exactly? §

Self hosting is about freedom, you can choose what server you want to run, which version, which features and which configuration you want. If you self host at home, You can also pick the hardware to match your needs (more Ram ? More Disk? RAID?).

Self hosting is not a perfect solution, you have to buy the hardware, replace faulty components, do the system maintenance to keep the software part alive.

3. Why does it matter? §

When you rely on a company or a third party offering services, you become tied to their ecosystem and their decisions. A company can stop what you rely on at any time, they can decide to suspend your account at any time without explanation. Companies will try to make their services good are appealing, no doubt on it, and then lock you in their ecosystem. For example, if you move all your projects on github and you start using github services deeply (more than a simple git repository), moving away from Github will be complicated because you don't have _reversibility_, which mean the right to get out and receive help from your service to move away without losing data or information.

Self hosting empower the users instead of making profit from them. Self hosting is better when it's done in community, a common mail server for a group of people and a communication server federated to a bigger network (such as XMPP or Matrix) are a good way to create a resilient Internet while not giving away your rights to capitalist companies.

4. Community hosting §

Asking everyone to host their own services is not even utopia but rather stupid, we don't need everyone to run their own server for their own services, we should rather build a constellation of communities that connect using federated protocol such as Email, XMPP, Matrix, ActivityPub (protocol used for Mastodon, Pleroma, Peertube).

In France, there is a great initiative named CHATONS (which is the french word for KITTENS) gathering associative hosting with some pre-requisites like multiple sysadmin to avoid relying on one person.

[English] CHATONS website

[French] Site internet du collectif CHATONS

In Catalonia, a similiar initiative started:

[Catalan] Mixetess website

5. Quality of service §

I suppose most of my readers will argue that self hosting is nice but can't compete with "cloud" services, I admit this is true. Companies put a lot of money to make great services to get customers and earn money, if their service were bad, they wouldn't exist long.

But not using open source and self hosting won't make alternatives to your service provider greater, you become part of the problem by feeding the system. For example, Google Mail GMAIL is now so big that they can decide which domain is allowed to reach them and which can't. It is such a problem that most small email servers can't send emails to Gmail without being treated as spam and we can't do anything to it, the more users they are, the less they care about other providers.

Great achievements can be done in open source federated services like Peertube, one can host videos on a Peertube instance and follow the local rules of the instance, while some other big companies could just disable your video because some automatic detection script found a piece of music or inappropriate picture.

Giving your data to a company and relying on their services make you lose your freedom. If you don't think it's true this is okay, freedom is a vague concept and it comes with various steps on a high scale.

6. Tips for self hosting §

Here are a few tips if you want to learn more about hosting your own services.

  • ask people you trust if they want to participate, it's better to have more than only one person to manage servers.
  • you don't need to be an IT professional, but you need to understand you will have to learn.
  • backups are not a luxury, they are mandatory.
  • asking (for contributing or as a requirement) for money is fine as long as you can justify why (a peertube server can be very expensive to run for example).
  • people around usually throw old hardware, ask friends or relative if they have old unused hardware. You can easily repair "that old Windows laptop I replaced because wifi stopped working" and use it as a server.
  • electricity usage must be considered but on the other hand, buying a brand new hardware to save 20W is not necessarily more ecological.
  • some services such as email servers can't be hosted on most ISP connection due to specific requirements
  • you will certainly need to buy a domain name
  • redundancy is overkill most of the time, shit happens but in redundant servers shit happens twice more often

IndieWeb website: a community proposing alternatives to the "corporate web".

There is a Linux disribution dedicated to self hosting named "Yunohost" (Y U No Host) that make the task really easy and give you a beginner friendly interface to manage your own service.

Yunohost website

Yunohost documentation "What is Yunohost ?"

7. Conclusion §

I'm self hosting since I first understood running a web server was the only thing I required to have my own PHP forum 15 years ago. I mostly keep this blog alive to show and share my experiments, most of the time happening when playing with my self hosting servers.

I have a strong opinion on the subject, hosting your own services is a fantastic way to learn new skills or perfect them, but it's also important for freedom. In France we even have associative ISP and even if they are small, their existence force the big ISP companies to be transparent on their processes and interoperatibility.

If you disagree with me, this is fine.

Self host your Podcast easily with potcasse

Written by Solène, on 21 July 2021.
Tags: #openbsd #scripts #podcast

Comments on Fediverse/Mastodon

1. Introduction §

I wrote « potcasse », pronounced "pot kas", a tool to help people to publish and self host a podcast easily without using a third party service. I found it very hard to find information to self host your own podcast and make it available easily on "apps" / podcast players so I wrote potcasse.

2. Where to get it §

Get the code from git and run "make install" or just copy the script "potcasse" somewhere available in your $PATH. Note that rsync is a required dependency.

Gitea access to potcasse

direct git url to the sources

3. What is it doing? §

Potcasse will gather your audio files with some metadata (date, title), some information about your Podcast (name, address, language) and will create an output directory ready to be synced on your web server.

Potcasse creates a RSS feed compatible with players but also a simple HTML page with a summary of your episodes, your logo and the podcast title.

4. Why potcasse? §

I wanted to self host my podcast and I only found Wordpress, Nextcloud or complex PHP programs to do the job, I wanted something static like my static blog that will work on any hosting platform securely.

5. How to use it §

The process is simple for initialization:

  • init the project directory using "potcasse init"
  • edit the metadata.sh file to configure your Podcast

Then, for every new episode:

  • import audio files using "potcasse episode" with the required arguments
  • generate the html output directory using "potcasse gen"
  • use rsync to push the output directory to your web server

There is a README file in the project that explain how to configure it, once you deploy you should have an index.html file with links to your episodes and also a link for the RSS feed that can be used in podcast applications.

6. Conclusion §

This was a few hours of work to get the job done, I'm quite proud of the result and switched my podcast (only 2 episodes at the moment...) to it in a few minutes. I wrote the commands lines and parameters while trying to use it as if it was finished, this helped me a lot to choose what is required, optional, in which order, how I would like to manually make changes as an author etc...

I hope you will enjoy this simple tool as much as I do.

Simple scripts I made over time

Written by Solène, on 19 July 2021.
Tags: #openbsd #scripts #shell

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to share a few scripts of mine for some time, here they are!

2. Scripts §

Over time I'm writing a few scripts to help me in some tasks, they are often associated to a key binding or at least in my ~/bin/ directory that I add to my $PATH.

2.1. Screenshot of a region and upload §

When I want to share something displayed on my screen, I use my simple "screen_up.sh" script (super+r) that will do the following:

  • use scrot and let me select an area on the screen
  • convert the file in jpg but also png compression using pngquant and pick the smallest file
  • upload the file to my remote server in a directory where files older than 3 days are cleaned (using find -ctime -type f -delete)
  • put the link in the clipboard and show a notification

This simple script has been improved a lot over time like getting a feedback of the result or picking the smallest file from various combinations.

#!/bin/sh
test -f /tmp/capture.png && rm /tmp/capture.png
scrot -s /tmp/capture.png
pngquant -f /tmp/capture.png
convert /tmp/capture-fs8.png /tmp/capture.jpg
FILE=$(ls -1Sr /tmp/capture* | head -n 1)
EXTENSION=${FILE##*.}

MD5=$(md5 -b "$FILE" | awk '{ print $4 }' | tr -d '/+=' )

ls -l $MD5

scp $FILE perso.pw:/var/www/htdocs/solene/i/${MD5}.${EXTENSION}
URL="https://perso.pw/i/${MD5}.${EXTENSION}"
echo "$URL" | xclip -selection clipboard

notify-send -u low $URL

2.2. Uploading a file temporarily §

Second most used script of mine is a uploading file utility. It will rename a file using the content md5 hash but keeping the extension and will upload it in a directory on my server where it will be deleted after a few days from a crontab. Once the transfer is finished, I get a notification and the url in my clipboard.

#!/bin/sh
FILE="$1"

if [ -z "$1" ]
then
        echo "usage: [file]"
        exit 1
fi
                
                
MD5=$(md5 -b "$1" | awk '{ print $NF }' | tr -d '/+=' )
NAME=${MD5}.${FILE##*.}

scp "$FILE" perso.pw:/var/www/htdocs/solene/f/${NAME}

URL="https://perso.pw/f/${NAME}"
echo -n "$URL" | xclip -selection clipboard

notify-send -u low "$URL"

2.3. Sharing some text or code snippets §

While I can easily transfer files, sometimes I need to share a snippet of code or a whole file but I want to ease the reader work and display the content in an html page instead of sharing an extension file that will be downloaded. I don't put those files in a cleaned directory and I require a name to give some clues about the content to potential readers. The remote directory contains a highlight.js library used to use syntactic coloration, hence I pass the text language to use the coloration.

#!/bin/sh

if [ "$#" -eq 0 ]
then
        echo "usage: language [name] [path]"
        exit 1
fi

cat > /tmp/paste_upload <<EOF
<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
</head>
<body>
        <link rel="stylesheet" href="default.min.css">
        <script src="highlight.min.js"></script>
        <script>hljs.initHighlightingOnLoad();</script>

        <pre><code class="$1">
EOF

# ugly but it works
cat /tmp/paste_upload | tr -d '\n' > /tmp/paste_upload_tmp
mv /tmp/paste_upload_tmp /tmp/paste_upload

if [ -f "$3" ]
then
    cat "$3" | sed 's/</\&lt;/g' | sed 's/>/\&gt;/g' >> /tmp/paste_upload
else
    xclip -o | sed 's/</\&lt;/g' | sed 's/>/\&gt;/g' >> /tmp/paste_upload
fi


cat >> /tmp/paste_upload <<EOF


</code></pre> </body> </html>
EOF


if [ -n "$2" ]
then
    NAME="$2"
else
    NAME=temp
fi

FILE=$(date +%s)_${1}_${NAME}.html

scp /tmp/paste_upload perso.pw:/var/www/htdocs/solene/prog/${FILE}

echo -n "https://perso.pw/prog/${FILE}" | xclip -selection clipboard
notify-send -u low "https://perso.pw/prog/${FILE}"

2.4. Resize a picture §

I never remember how to resize a picture so I made a one line script to not have to remember about it, I could have used a shell function for this kind of job.

#!/bin/sh

if [ -z "$2" ]
then
	PERCENT="40%"
else
	PERCENT="$2"
fi

convert -resize "$PERCENT" "$1" "tn_${1}"

3. Latency meter using DNS §

Because UDP requests are not reliable they make a good choice for testing network access reliability and performance. I used this as part of my stumpwm window manager bar to get the history of my internet access quality while in a high speed train.

The output uses three characters to tell if it's under a threshold (it works fine), between two threshold (not good quality) or higher than the second one (meaning high latency) or even a network failure.

The default timeout is 1s, if it works, under 60ms you get a "_", between 60ms and 150ms you get a "-" and beyond 150ms you get a "¯", if the network is failure you see a "N".

For example, if your quality is getting worse until it breaks and then works, it may look like this: _-¯¯NNNNN-____-_______ My LISP code was taking care of accumulating the values and only retaining the n values I wanted as history.

Why would you want to do that? Because I was bored in a train. But also, when network is fine, it's time to sync mails or refresh that failed web request to get an important documentation page.

#!/bin/sh

dig perso.pw @9.9.9.9  +timeout=1 | tee /tmp/latencecheck

if [ $? -eq 0 ]
then
        time=$(awk '/Query time/{
                if($4 < 60) { print "_";}
                if($4 >= 60 && $4 <= 150) { print "-"; }
                if($4 > 150) { print "¯"; }
        }' /tmp/latencecheck)
        echo $time | tee /tmp/latenceresult
else
        echo "N" | tee /tmp/latenceresult
    exit 1
fi

4. Conclusion §

Those scripts are part of my habits, I'm a bit lost when I don't have them because I always feel they are available at hand. While they don't bring much benefits, it's quality of life and it's fun to hack on small easy pieces of programs to achieve a simple purpose. I'm glad to share those.

The Old Computer Challenge: day 7

Written by Solène, on 16 July 2021.
Tags: #openbsd #life #oldcomputerchallenge

Comments on Fediverse/Mastodon

Report of the last day of the old computer challenge.

1. A journey §

I'm writing this text while in the last hours of the challenge, I may repeat some thoughts and observations already reported in the earlier posts but never mind, this is the end of the journey.

2. Technical §

Let's speak about Tech! My computer is 16 years old but I've been able to accomplish most of what I enjoy on a computer: IRC, reading my mails, hacking on code and reading some interesting content on the internet. So far, I've been quite happy about my computer, it worked without any trouble.

On the other hand, there were many tasks that didn't work at all:

  • Browsing the internet to use "modern" website relying on javascript: this is because Javascript capable browsers are not working on my combination of operating system/CPU architecture, I'm quite sure the challenge would have been easier with an old amd64 computer even with low memory.
  • Watching videos: for some reasons, mplayer in full screen was producing a weird issue, computer stopped working but cursor was still moving but nothing more was possible. However it worked correctly for most videos.
  • Listening to my big FLAC music files, if doing so I wasn't able to do anything else because of the CPU usage and sitting on my desk to listen to music was not an interesting option.
  • Using Go, Rust and Node programs because there are no implementation of these languages on OpenBSD PowerPC 32bits.

On the hardware side, here is what I noticed:

  • 512MB are quite enough as long as you stay focused on one task, I rarely required to use swap even with multiple programs opened.
  • I don't really miss spinning hard drive, in term of speed and noise, I'm happy they are gone in my newer computers.
  • Using an external pointing device (mouse/trackball) is so much better than the bad touchpad.
  • Modern screens are so much better in term of resolution, colours and contrast!
  • They keyboard is pleasant but lack a "Super" modifier key which lead to issues with key binding overlapping between the window manager and programs.
  • Suspend and resume doesn't work on OpenBSD, so I had to boot the computer and it takes a few minutes to do so and require manual step to unlock /home which add delay for boot sequence.

Despite everything the computer was solid but modern hardware is such more pleasant to use in many ways, not only in term of raw speed. When you buy a laptop especially, you should take care about the other specs than the CPU/memory like the case, the keyboard, the touchpad and the screen, if you use a lot your laptop they are as much important as the CPU itself in my opinion.

Thanks to the programs w3m, catgirl, luakit, links, neomutt, claws-mail, ls, make, sbcl, git, rednotebook, keepassxc, gimp, sxiv, feh, windowmaker, fvwm, ratpoison, ksh, fish, mplayer, openttd, mednafen, rsync, pngquant, ncdu, nethack, goffice, gnumeric, scrot, sct, lxappearence, tootstream, toot, OpenBSD and all the other programs I used for this challenge.

3. Human §

Because I always felt this challenge was a journey to understand my use of computer, I'm happy of the journey.

To make things simple, here is a bullet list of what I noticed

  • Going to sleep earlier instead of waiting for something to happen.
  • I've spent a lot less time on my computer but at the same time I don't notice it much in term of what I've done with it, this mean I was more "productive" (writing blog, reading content, hacking) and not idling.
  • I didn't participate into web forums of my communities :(
  • I cleared things in my todo list on my server (such as replacing Spamassassin by rspamd and writing about it).
  • I've read more blogs and interesting texts than usual, and I did it without switching to another task.
  • Javascript is not ecological because it prevent older hardware to be usable. If I didn't needed javascript I guess I could continue using this laptop.
  • I got time to discover and practice meditation.
  • Less open source contribution because compiling was too slow.

I'm sad and disappointed to notice I need to work on my self discipline (that's why I started to learn about meditation) to waste less time on my computer. I will really work on it, I see I can still do the same tasks but spend less time doing nothing/idling/switching tasks.

I will take care of supporting old systems by my contributions, like my blog working perfectly fine in console web browsers but also trying to educate people about this.

I've met lot of interesting people on the IRC channel and for this sole reason I'm happy I made the challenge.

4. Conclusion §

Good hardware is good but is not always necessary, it's up to the developers to make good use of the hardware. While some requirements can evolve over time like cryptography or video codecs, programs shouldn't become more and more resources hungry for the reason that we have more and more available. We have to learn how todo MORE with LESS with computers and it was something I wanted to highlight with this challenge.

The Old Computer Challenge: day 6

Written by Solène, on 15 July 2021.
Tags: #openbsd #life #oldcomputerchallenge

Comments on Fediverse/Mastodon

1. Report §

This is the 6th day of the challenge! Time went quite fast.

2. Mood §

I got quite bored two days ago because it was very frustrating to not be able to do everything I want. I wanted to contribute to OpenBSD but the computer is way to slow to do anything useful beyond editing files.

Although, it got better yesterday, 5th day of the challenge, when I decided to move away from claws-mail and switch to neomutt for my emails. I updated claws-mail to version 4.0.0 freshly released and starting updating the OpenBSD package, but claws-mail switched to gtk3 and it became too slow for the computer.

I started using a mouse on the laptop and it made some tasks more enjoyable although I don't need it too much because most of my programs are in a console but every time I need the cursor it's more pleasant to use a mouse support 3 clicks + wheel.

3. Software §

The computer is the sum of its software. Here is a list of the software I'm using right now:

  • fvwm2: window manager, doesn't bug with full screen programs and is light enough and I like it.
  • neomutt: mail reader, I always hate mutt/neomutt because of the complexity of their config file, fortunately I had some memories of when I used it and I've been able to build a nice simple configuration script and took the opportunity to update my Neomutt cheatsheet article.
  • w3m: in my opinion it's the best web browser in terminal :) the bookmark feature works very great and using https://lite.duckduckgo.com/lite for searches works perfectly fine. I use the flavor with image rendering support, however I have mixed feelings about it because pictures take time to download and render and will always render at their original size which is a pain most of the time.
  • keepassxc: my usual password manager, it has a cli command line to manage the entries from a shell after unlocking the database.
  • openttd: a game of legend that is relaxing and also very fun to play, runs fine after a few tweaks.
  • mastodon: tootstream but it's quite limited sometimes and I also access Mastodon on my phone with Tusky from F-droid, they make a great combination.
  • rednotebook: I was already using it on this computer when it was known as the "offline computer", this program is a diary where I write my day when I feel bad (anger, depressed, bored), it doesn't have much entries in it but it really helps me to write things down. While the program is very heavy and could be considered bloated for the purpose of writing about your day, I just like it because it works and it looks nice.

I'm often asked how I deal with youtube, I just don't, I don't use youtube so problem is solved :-) I use no streaming services at home.

4. Breaking the challenge §

I had to use my regular computer to order a pizza because the stupid pizza company doesn't want to take orders by phone and they are the only pizza shop around... :( I could have done using my phone but I don't really trust my phone web browser to support all the operations of the process.

I could easily handle using this computer for more time if I hadn't so many requirements on web services, mostly for ordering products I can't find locally (pizza doesn't count here) and I hate using my phone for web access because I hate smartphone most of the time.

If I had used an old i386 / amd64 computer I would have been able to use a webkit browser even if it was slow, but on PowerPC the state of web browser with javascript is complicated and currently none works for me on OpenBSD.

Filtering spam using Rspamd and OpenSMTPD on OpenBSD

Written by Solène, on 13 July 2021.
Tags: #openbsd #mail #spam

Comments on Fediverse/Mastodon

1. Introduction §

I recently used Spamassassin to get ride of the spam I started to receive but it proved to be quite useless against some kind of spam so I decided to give rspamd a try and write about it.

rspamd can filter spam but also sign outgoing messages with DKIM, I will only care about the anti spam aspect.

rspamd project website

2. Setup §

The rspamd setup for spam was incredibly easy on OpenBSD (6.9 for me when I wrote this). We need to install the rspamd service but also the connector for opensmtpd, and also redis which is mandatory to make rspamd working.

pkg_add opensmtpd-filter-rspamd rspamd redis
rcctl enable redis rspamd
rcctl start redis rspamd

Modify your /etc/mail/smtpd.conf file to add this new line:

filter rspamd proc-exec "filter-rspamd"

And modify your "listen on ..." lines to add "filter "rspamd"" to it, like in this example:

listen on em0 pki perso.pw tls auth-optional   filter "rspamd"
listen on em0 pki perso.pw smtps auth-optional filter "rspamd"

Restart smtpd with "rcctl restart smtpd" and you should have rspamd working!

3. Using rspamd §

Rspamd will automatically check multiple criteria for assigning a score to an incoming email, beyond a high score the email will be rejected but between a low score and too high, it may be tagged with a header "X-spam" with the value true.

If you want to automatically put the tagged email as spam in your Junk directory, either use a sieve filter on the server side or use a local filter in your email client. The sieve filter would look like this:


if header :contains "X-Spam" "yes" {
        fileinto "Junk";
        stop;
}

4. Feeding rspamd §

If you want better results, the filter needs to learn what is spam and what is not spam (named ham). You need to regularly scan new emails to increase the effectiveness of the filter, in my example I have a single user with a Junk directory and an Archives directory within the maildir storage, I use crontab to run learning on mails newer than 24h.

0  1 * * * find /home/solene/maildir/.Archives/cur/ -mtime -1 -type f -exec rspamc learn_ham {} +
10 1 * * * find /home/solene/maildir/.Junk/cur/     -mtime -1 -type f -exec rspamc learn_spam {} +

5. Getting statistics §

rspamd comes with very nice reporting tools, you can get a WebUI on the port 11334 which is listening on localhost by default so you would require tuning rspamd to listen on other addresses or you can use a SSH tunnel.

You can get the same statistics on the command line using the command "rspamc stat" which should have an output similar to this:

Results for command: stat (0.031 seconds)
Messages scanned: 615
Messages with action reject: 15, 2.43%
Messages with action soft reject: 0, 0.00%
Messages with action rewrite subject: 0, 0.00%
Messages with action add header: 9, 1.46%
Messages with action greylist: 6, 0.97%
Messages with action no action: 585, 95.12%
Messages treated as spam: 24, 3.90%
Messages treated as ham: 591, 96.09%
Messages learned: 4167
Connections count: 611
Control connections count: 5190
Pools allocated: 5824
Pools freed: 5801
Bytes allocated: 31.17MiB
Memory chunks allocated: 158
Shared chunks allocated: 16
Chunks freed: 0
Oversized chunks: 575
Fuzzy hashes in storage "rspamd.com": 2936336370
Fuzzy hashes stored: 2936336370
Statfile: BAYES_SPAM type: redis; length: 0; free blocks: 0; total blocks: 0; free: 0.00%; learned: 344; users: 1; languages: 0
Statfile: BAYES_HAM type: redis; length: 0; free blocks: 0; total blocks: 0; free: 0.00%; learned: 3822; users: 1; languages: 0
Total learns: 4166

6. Conclusion §

rspamd is for me a huge improvement in term of efficiency, when I tag an email as spam the next one looking similar will immediately go into Spam after the learning cron runs, it draws less memory then Spamassassin and reports nice statistics. My Spamassassin setup was directly rejecting emails so I didn't have a good comprehension of its effectiveness but I got too many identical messages over weeks that were never filtered, for now rspamd proved to be better here.

I recommend looking at the configurations files, they are all disabled by default but offer many comments with explanations which is a nice introduction to learn about features of rspamd, I preferred to keep the defaults and see how it goes before tweaking more.

The Old Computer Challenge: day 3

Written by Solène, on 12 July 2021.
Tags: #openbsd #life #oldcomputerchallenge

Comments on Fediverse/Mastodon

Report of the third day of the old computer challenge.

1. Community §

I got a lot of feedback from the community, the IRC channel #oldcomputerchallenge is quite active and it seems we have a small community that may start here. I received help from various question I had in regards to the programs I'm now using.

2. Changes §

2.1. Web is a pity §

The computer I use is using a different processor architecture than we we are used too. Our computers are now amd64 (even the intel one, amd64 is the name of the instruction sets of the processors) or arm64 for most tablets/smartphone or small boards like raspberry PI, my computer is a PowerPC but it disappeared around 2007 from the market. It is important to know that because most language virtual machines (for interpreted languages) requires some architecture specifics instructions to work, and nobody care much about PowerPC in the javascript land (that could be considered wasting time given the user base), so I'm left without a JS capable web browser because they would instantly crash. The person of cwen@ at the OpenBSD project is pushing hard to fix many programs on PowerPC and she is doing an awesome work, she got JS browsers to work through webkit but for some reasons they are broken again so I have to do without those.

w3m works very fine, I learned about using bookmarks in it and it makes w3m a lot more usable for daily stuff, I've been able to log-in on most websites but I faced some buttons not working because they triggered a javascript action. I'm using it with built-in support for images but it makes loading time longer and they are displayed with their real size which can screw up the display, I'm think I'll disable the image support...

2.2. Long live to the smolnet §

What is the smolnet? This is a word that feature what is not on the Web, this includes mostly content from Gopher and Gemini. I like that word because it represents an alternative that I'm contributing too for years and the word carries a lot of meaning.

Gopher and Gemini are way saner to browse, thanks to a standard concept of one item per line and no style, visiting one page feels like all the others and I don't have to look for where the menu is, or even wait for the page to render. I've been recommended the av-98 terminal browser and it has a very lovely feature named "tour", you can accumulate links from pages you visit and add them to the tour, and them visit the next liked accumulated (like a First in-First out queue), this avoids cumbersome tabs or adding bookmarks for later viewing and forgetting about them.

2.3. Working on OpenBSD ports §

I'm working at updating the claws-mail mail client package on OpenBSD, a new major release was done the first day of the challenge, unfortunately working with it is extremely painful on my old computer. Compiling was long, but was done only once, now I need to sort out libraries includes and using the built-in check of the ports tree takes like 15 minutes which is really not fun.

2.4. I hate the old hardware §

While I like this old laptop, I start to hate it too. The touchpad is extremely bad and move by increments of 5px or so which is extremely imprecise especially for copy/pasting text or playing OpenTTD, not mentioning again that it only has a left click button. (update, it has been fixed thanks to anthk_ on IRC using the command xinput set-prop /dev/wsmouse "Device Accel Constant Deceleration" 1.5)

The screen has a very poor contrast, I can deal with a 1024x768 resolution and I love the 4:3 ratio, but the lack of contrast is really painful to deal with.

The mechanical hard drive is slow, I can cope with that, but it's also extremely noisy, I forgot the crispy noises of the old HDD. It's so annoying to my hears... And talking about noise, I'm often limiting the CPU speed of my computer to avoid the temperature rising too high and triggering the super loud small CPU fan. It is really super loud and it doesn't seem quite effective, maybe the thermal paste is old...

A few months ago I wanted to replace the HDD but I looked on iFixit website the HDD replacement procedure for this laptop and there are like 40 steps to follow plus an Apple specific screwdriver, the procedure basically consists at removing all parts of the laptop to access the HDD which seems the piece of hardware in the most remote place in the case. This is insane, I'm used to work on Thinkpad laptop and after removing 4 usual screws you get access to everything, even my T470 internal battery is removable.

All of these annoying facts are not even related to the computer power but simply because modern hardware evolved, they are quality of life because they don't make the computer more or less usable, but more pleasant. Silence, good and larger screens and multiple fingers gestures touchpad bring a more comfortable use of the computer.

2.5. Taking my time §

Because of context switching cost a lot of time, I take my time to read content and appreciate it in one shot instead of bookmarking after reading a few lines and never read the bookmark again. I was quite happy to see I'm able to focus more than 2 minutes on something and I'm a bit relieved in that regards.

2.6. Psychological effect §

I'm quite sad to see an older system forcing me to restriction can improve my focus, this mean I'm lacking self discipline and that I've wasted too much time of my life doing useless context/task switching. I don't want to rely on some sort of limitations to be guards of my sanity, I have to work on this on my own, maybe meditation could be me getting my patience back.

3. End of report of day 3 §

I'm meeting friendly people sharing what I like, I realizing my dependencies over services or my lack of self mental discipline. The challenge is a lot harder than I expected but if it was too easy that wouldn't be a challenge. I already know I'll be happy to get back to my regular laptop but I also think I'll change some habits.

The Old Computer Challenge: day 1

Written by Solène, on 10 July 2021.
Tags: #openbsd #life #oldcomputerchallenge

Comments on Fediverse/Mastodon

Report of my first day of the old computer challenge

1. My setup §

I'm using an Apple iBook G4 running the operating system development version of OpenBSD macppc. Its specs are: 1 CPU G4 1.3GHz, 512 MB of memory and an old IDE HDD 40 GB. The screen is a 4/3 ratio with a 1024x768 resolution. The touchpad has only one tap button doing left click, the touchpad doesn't support multiple fingers gestures (can't scroll, can't click). The battery is still holding a 1h40 capacity which is very surprising.

About the software, I was using the ratpoison window manager but I got issue with two GUI applications so I moved to cwm but I have other issues with cwm now. I may switch to window maker maybe or return to ratpoison which worked very well except for 2 programs, and switch to cwm when I need them... I use xterm as my terminal emulator because "it works" and it doesn't draw much memory, usually I'm using Sakura but with 32 MB of memory for each instance vs 4 MB for xterm it's important to save memory now. I usually run only one xterm with a tmux inside.

Same for the shell, I've been using fish since the beginning of 2021 but each instance of fish draws 9 MB which is quite a lot because this mean every time I split my tmux and this spawns a new shell then I have an extra 9MB used. ksh draws only 1MB per instance which is 9x less than fish, however for some operations I still switch to fish manually because it's a lot more comfortable for many operations due to its lovely completion.

2. Tasks §

Tasks on the day and how I complete them.

2.1. Searching on the internet §

My favorite browser on such old system is w3m with image support in the terminal, it's super fast and the render is very good. I use https://html.duckduckgo.com/html/ as my search engine.

The only false issue with w3m is that the key bindings are absolutely not straightforward but you only need to know a few of them to use it and they are all listed in the help.

2.2. Using mastodon §

I spend a lot of time on Mastodon to communicate with people, I usually use my web browser to access mastodon but I can't here because javascript capable web browser takes all the memory and often crash so I can only use them as a last joker. I'm using the terminal user interface tootstream but it has some limitations and my high traffic account doesn't match well with it. I'm setting up brutaldon which is a local program that gives access to mastodon through an old style website, I already wrote about it on my blog if you want more information.

2.3. Listening to music §

Most of my files are FLAC encoded and are extremely big, although the computer can decode them right but this uses most of the CPU. As OpenBSD doesn't support mounting samba shares and that my music is on my NAS (in addition to locally on my usual computer), I will have to copy the files locally before playing them.

One solution is to use musikcube on my NAS and my laptop with the server/client setup which will make my nas transcoding the music I want to play on the laptop on the fly. Unfortunately there is no package for musikcube yet and I started compiling it on my old laptop and I suppose it will take a few hours to complete.

2.4. Reading emails §

My favorite email client at the moment is claws-mail and fortunately it runs perfectly fine on this old computer, although the lack of right click is sometimes a problem but a clever workaround is to run "xdotool click 3" to tell X to do a right click where the cursor is, it's not ideal but I rarely need it so it's ok. The small screen is not ideal to deal with huge piles of mails but it works so far.

2.5. IRC §

My IRC setup is to have a tmux with as many catgirl (irc client) instances as network I'm connected too, and this is running on a remote server so I just connect there with ssh and attach to the local tmux. No problem here.

2.6. Writing my blog §

The process is exactly the same as usual. I open a terminal to start my favorite text editor, I create the file and write in it, then I run aspell to check for typos, then I run "make" to make my blog generator creates the html/gopher/gemini versions and dispatch them on the various server where they belong to.

3. How I feel §

It's not that easy! My reliance on web services is hurting here, I found a website providing weather forecast working in w3m.

I easily focus on a task because switching to something else is painful (screen redrawing takes some times, HDD is noisy), I found a blog from a reader linking to other blogs, I enjoyed reading them all while I'm pretty sure I would usually just make a bookmark in firefox and switch to a 10-tabs opening to see what's new on some websites.

Obsolete in the IT crossfire

Written by Solène, on 09 July 2021.
Tags: #life #linux #unix #openbsd

Comments on Fediverse/Mastodon

1. Preamble §

This is not an article about some tech but more me sharing feelings about my job, my passion and IT. I've met a Linux system at first in the early 2000 and I didn't really understand what this was, I've learned it the hard way by wiping Windows on the family computer (which was quite an issue) and since that time I got a passion with computers. I made a lot of mistakes that made me progress and learn more, and the more I was learning, the more I saw the amount of knowledge I was missing.

Anyway, I finally got a decent skill level if I could say, but I started early and so my skill is related to all of that early Linux ecosystem. Tools are evolving, Linux is morphing into something different a bit more every year, practices are evolving with the "Cloud". I feel lost.

2. Within the crossfire §

I've met many people along my ride in open source and I think we can distinguish two schools (of course I know it's not that black and white): the people (like me) who enjoy the traditional ecosystem and the other group that is from the Cloud era. It is quite easy to bash the opposite group and I feel sad when I assist at such dispute.

I can't tell which group is right and which is wrong, there is certainly good and bad in both. While I like to understand and control how my system work, the other group will just care about the produced service and not the underlying layers. Nowadays, you want your service uptime to have as much nine as you can afford (99.999999) at the cost of having complex setup with automatic respawning services on failure, automatic routing within VMs and stuff like that. This is not necessarily something that I enjoy, I think a good service should have a good foundation and restarting the whole system upon failure seems wrong, although I can't deny it's effective for the availability.

I know how a package manager work but the other group will certainly prefer to have a tool that will hide all of the package manager complexity to get the job done. Tell ansible to pop a new virtual machine on Amazon using Terraform with a full nginx-php-mysql stack installed is the new way to manage servers. It seems a sane option because it gets the job done, but still, I can't find myself in there, where is the fun? I can't get the fun out of this. You can install the system and the services without ever see the installer of the OS you are deploying, this is amazing and insane at the same time.

I feel lost in this new era, I used to manage dozens of system (most bare-metal, without virtualization), I knew each of them that I bought and installed myself, I knew which process should be running and their usual CPU/memory usage, I got some acquaintance with all my systems. I was not only the system administrator, I was the IT gardener. I was working all the time to get the most out of our servers, optimizing network transfers, memory usage, backups scripts. Nowadays you just pop a larger VM if you need more resources and backups are just snapshots of the whole virtual disk, their lives are ephemeral and anonymous.

3. To the future §

I would like to understand better that other group, get more confident with their tools and logic but at the same time I feel some aversion toward doing so because I feel I'm renouncing to what I like, what I want, what made me who I am now. I suppose the group I belong too will slowly fade away to give room to the new era, I want to be prepared to join that new era but at the same time I don't want to abandon the people of my own group by accelerating the process.

I'm a bit lost in this crossfire. Should a resistance organize against this? I don't know, I wouldn't see the point. The way we do computing is very young, we are looking for a way. Humanity has been making building for thousands and years and yet we still improve the way we build houses, bridges and roads, I guess that the IT industry is following the same process but as usual with computers, at an insane rate that humans can barely follow.

4. Next §

Please share with me by email or mastodon or even IRC if you feel something similar or if you got past that issue, I would be really interested to speak about this topic with other people.

5. Readers reactions §

ew.srht.site reply

6. After thoughts (UPDATE post publication) §

I got many many readers giving me their thoughts about this article and I'm really thankful for this.

Now I think it's important to realize that when you want to deploy systems at scale, you need to automate all your infrastructure and then you lose that feeling with your servers. However, it's still possible to have fun because we need tooling, proper tooling that works and bring a huge benefit. We are still very young in regards to automation and lot of improvements can be done.

We will still need all those gardeners enjoying their small area of computer because all the cloud services rely on their work to create duplicated system in quantity that you can rely on. They are making the first most important bricks required to build the "Cloud", without them you wouldn't have a working Alpine/CentOS/FreeBSD/etc... to deploy automatically.

Both can coexist, both should know better each other because they will have to live together to continue the fantastic computer journey, however the first group will certainly be in a small number compared to the other.

So, not everything is lost! The Cloud industry can be avoided by self-hosting at home or in associative datacenter/colocations but it's still possible to enjoy some parts of the great shift without giving up all we believe in. A certain balance can be found, I'm quite sure of it.

OpenBSD: pkg_add performance analysis

Written by Solène, on 08 July 2021.
Tags: #bandwidth #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

OpenBSD package manager pkg_add is known to be quite slow and using much bandwidth, I'm trying to figure out easy ways to improve it and I may nailed something today by replacing ftp(1) http client by curl.

2. Testing protocol §

I used on an OpenBSD -current amd64 the following command "pkg_add -u -v | head -n 70" which will check for updates of the 70 first packages and then stop. The packages tested are always the same so the test is reproducible.

The traditional "ftp" will be tested, but also "curl" and "curl -N".

The bandwidth usage has been accounted using "pfctl -s labels" by a match rule matching the mirror IP and reset after each test.

3. What happens when pkg_add runs §

Here is a quick intro to what happens in the code when you run pkg_add -u on http://

  • pkg_add downloads the package list on the mirror (which could be considered to be an index.html file) which weights ~2.5 MB, if you add two packages separately the index will be downloaded twice.
  • pkg_add will run /usr/bin/ftp on the first package to upgrade to read its first bytes and pipe this to gunzip (done from perl from pkg_add) and piped to signify to check the package signature. The signature is the list of dependencies and their version which is used by pkg_add to know if the package requires update and the whole package signify signature is stored in the gzip header if the whole package is downloaded (there are 2 signatures: signify and the packages dependencies, don't be mislead!).
  • if everything is fine, package is downloaded and the old one is replaced.
  • if there is no need to update, package is skipped.
  • new package = new connection with ftp(1) and pipes to setup

Using FETCH_CMD variable it's possible to tell pkg_add to use another command than /usr/bin/ftp as long as it understand "-o -" parameter and also "-S session" for https:// connections. Because curl doesn't support the "-S session=..." parameter, I used a shell wrapper that discard this parameter.

4. Raw results §

I measured the whole execution time and the total bytes downloaded for each combination. I didn't show the whole results but I did the tests multiple times and the standard deviation is near to 0, meaning a test done multiple time was giving the same result at each run.

operation               time to run     data transferred
---------               -----------     ----------------
ftp http://             39.01           26
curl -N http://	        28.74           12
curl http://            31.76           14
ftp https://            76.55           26
curl -N https://        55.62           15
curl https://           54.51           15
Charts with results
Charts with results

5. Analysis §

There are a few surprising facts from the results.

  • ftp(1) not taking the same time in http and https, while it is supposed to reuse the same TLS socket to avoid handshake for every package.
  • ftp(1) bandwidth usage is drastically higher than with curl, time seems proportional to the bandwidth difference.
  • curl -N and curl performs exactly the same using https.

6. Conclusion §

Using http:// is way faster than https://, the risk is about privacy because in case of man in the middle the download packaged will be known, but the signify signature will prevent any malicious package modification to be installed. Using 'FETCH_CMD="/usr/local/bin/curl -L -s -q -N"' gave the best results.

However I can't explain yet the very different behaviors between ftp and curl or between http and https.

7. Extra: set a download speed limit to pkg_add operations §

By using curl as FETCH_CMD you can use the "--limit-rate 900k" parameter to limit the transfer speed to the given rate.

The Old Computer Challenge

Written by Solène, on 07 July 2021.
Tags: #linux #oldcomputerchallenge

Comments on Fediverse/Mastodon

1. Introduction §

For some time I wanted to start a personal challenge, after some thoughts I want to share it with you and offer you to join me in this journey.

The point of the challenge is to replace your daily computer by a very old computer and share your feelings for the week.

2. The challenge §

Here are the *rules* of the challenge, there are no prize to win but I'm convinced we will have feelings to share along the week and that it will change the way we interact with computers.

  • 1 CPU maximum, whatever the model. This mean only 1 CPU|Core|Thread. Some bios allow to disable multi core.
  • 512 MB of memory (if you have more it's not a big deal, if you want to reduce your ram create a tmpfs and put a big file in it)
  • using USB dongles is allowed (storage, wifi, Bluetooth whatever)
  • only for your personal computer, during work time use your usual stuff
  • relying on services hosted remotely is allowed (VNC, file sharing, whatever help you)
  • using a smartphone to replace your computer may work, please share if you move habits to your smartphone during the challenge
  • if you absolutely need your regular computer for something really important please use it. The goal is to have fun but not make your week a nightmare.

If you don't have an old computer, don't worry! You can still use your regularly computer and create a virtual machine with low specs, you would still be more comfortable with a good screen, disk access and a not too old CPU but you can participate.

3. Date §

The challenge will take place from 10Th July morning until 17Th July morning.

4. Social medias §

Because I want this event to be a nice moment to share with others, you can contact me so I can add your blog (including gopher/gemini space) to the future list below.

You can also join #oldcomputerchallenge on libera.chat IRC server.

prahou's blog, running a T42 with OpenBSD 6.9 i386 with hostname brouk

Joe's blog about the challenge and why they need it

Solene (this blog) running an iBook G4 with OpenBSD -current macppc with hostname jeefour

(gopher link) matto's report using FreeBSD 13 on an Acer aspire one

cel's blog using Void Linux PPC on an Apple Powerbook G4

Keith Burnett's blog using a T42 with an emphasis on using GUI software to see how it goes

Kuchikuu's blog using a T60 running Debian (but specs out of the challenge)

Ohio Quilbio Olarte's blog using an MSI Wind netbook with OpenBSD

carcosa's blog using an ASUS eeePC netbook with Fedora i386 downgraded with kernel command line

Tekk's website, using a Dell Latitude D400 (2003) running Slackware 14.2

5. My setup §

I use an old iBook G4 laptop (the one I already use "offline"), it has a single PowerPC G4 1.3 GHz CPU and 512 MB of ram and a slow 40GB HDD. The wifi is broken so I have to use a Wifi dongle but I will certainly rely on ethernet. The screen has a 1024x768 resolution but the colors are pretty bad.

In regards to software it runs OpenBSD 6.9 with /home/ encrypted which makes performance worse. I use ratpoison as the window manager because it saves screen space and requires little memory and CPU to run and is entirely keyboard driven, that laptop has only a left click touchpad button :).

I love that laptop and initially I wanted to see how far I could use for my daily driver!

Picture of the laptop
Picture of the laptop
Screenshot of the laptop
Screenshot of the laptop

Track changes in /etc with etckeeper

Written by Solène, on 06 July 2021.
Tags: #linux

Comments on Fediverse/Mastodon

1. Introduction §

Today I will introduce you to the program etckeeper, a simple tool that track changes in your /etc/ directory into a versioning control system (git, mercurial, darcs, bazaar...).

etckeeper project website

2. Installation §

Your system may certainly package it, you will then have to run "etckeeper init" in /etc/ the first time. A cron or systemd timer should be set by your package manager to automatically run etckeeper every day.

In some cases, etckeeper can integrate with package manager to automatically run after a package installation.

3. Benefits §

While it can easily be replicated using "git init" in /etc/ and then using "git commit" when you make changes, etckeeper does it automatically as a safety net because it's easy to forget to commit when we make changes. It also has integration with other system tools and can use hooks like sending an email when a change is found.

It's really a convenience tool but given it's very light and can be useful I think it's a must for most sysadmins.

Gentoo cheatsheet

Written by Solène, on 05 July 2021.
Tags: #linux #gentoo #cheatsheet

Comments on Fediverse/Mastodon

1. Introduction §

This is a simple cheatsheet to manage my Gentoo systems, a linux distribution source based, meaning everything installed on the computer must be compiled locally.

Gentoo project website

2. Upgrade system §

I use the following command to update my system, it will downloaded latest portage version and then rebuild @world (the whole set of packages manually installed).

#!/bin/sh
emerge-webrsync 2>&1 | grep "The current local"
if [ $? -eq 0 ]
then
	exit
fi

emerge -auDv --with-bdeps=y --changed-use --newuse @world

3. Use ccache §

As you may rebuild the same program many times (especially on a new install), I highly recommend using ccache to reuse previous builded objects and will reduce build duration by 80% when you change an USE.

It's quite easy, install ccache package, add 'FEATURES="ccache"' in your make.conf and do "install -d -o root -g portage -p 775" /var/cache/ccache and it should be working (you should see files in the ccache directory).

Gentoo wiki about ccache

4. Use emlop to view / calculate build time from past builds §

Emlop can tell you how much time will be needed or remains on a build based on previous builds information. I find it quite fun to see how long an upgrade will take.

There is another tool named "genlop" that is older, but emlop feels better.

4.1. View compilation time §

From the package emlop

# emlop predict
Pid 353165: ...-newuse --backtrack=150 @world       1:07:15 
sys-devel/gcc-12.2.1_p20230121-r1                   1:34:41 - 1:06:21

5. Using gentoolkit §

The gentoolkit package provides a few commands to find informations about packages.

Gentoo wiki page about Gentoolkit

5.1. Find a package §

You can use "equery" from the package gentoolkit like this "equery l -p '*package name*" globbing with * is mandatory if you are not looking for a perfect match.

Example of usage:

# equery l -p '*firefox*'
 * Searching for *firefox* ...
[-P-] [  ] www-client/firefox-78.11.0:0/esr78
[-P-] [ ~] www-client/firefox-89.0:0/89
[-P-] [ ~] www-client/firefox-89.0.1:0/89
[-P-] [ ~] www-client/firefox-89.0.2:0/89
[-P-] [  ] www-client/firefox-bin-78.11.0:0/esr78
[-P-] [  ] www-client/firefox-bin-89.0:0/89
[-P-] [  ] www-client/firefox-bin-89.0.1:0/89
[IP-] [  ] www-client/firefox-bin-89.0.2:0/89

5.2. Get the package name providing a file §

Use "equery b /path/to/file" like this

# equery b /usr/bin/2to3
 * Searching for /usr/bin/2to3 ... 
dev-lang/python-exec-2.4.6-r4 (/usr/lib/python-exec/python-exec2)
dev-lang/python-exec-2.4.6-r4 (/usr/bin/2to3 -> ../lib/python-exec/python-exec2)

5.3. Show installed packages §

qlist -I

6. Upgrade parts of the system using packages sets §

There are special packages sets like @security or @profile that can be used instead of @world that will restrict the packages to only a group, on a server you may only want to update @security for... security but not for newer versions.

Gentoo wiki about Packages sets

7. Disable network when emerging for extra security §

When building programs using emerge, you can disable the network access for the building process, this is considered a good thing because if the building process requires extra files downloaded or a git repository cloned during building phase, this mean your build is not reliable over time. This is also important for security because a rogue build script could upload data. This behavior is default on OpenBSD system.

To enable this, just add "network-sandbox" in the FEATURE variable in your make.conf file.

Gentoo documentation about make.conf variables

8. Easy trimming kernel process §

I had a bulky kernel at first but I decided to trim it down to reduce build time, it took me a long fail and retry process in order to have everything right that still work, here is a short explanation about my process.

  • keep an old kernel that work
  • install and configure genkernel with MRPROPER=no and CLEAN=no in /etc/genkernel.conf because we don't want to rebuild everything when we make changes
  • lspci -k will tell you which hardware requires which kernel module
  • visit /usr/src/linux and run make menuconfig, basically, you can remove a lot of things in "Device drivers" category that doesn't look like standard hardware on personal computers
  • in Ethernet, Wireless LAN, Graphical drivers, you can trim everything that doesn't look like your hardware
  • run genkernel all and then grub-mkconfig -o /boot/grub/grub.cfg if not done by genkernel and reboot, if something is missed, try enabling drivers you removed previously
  • do it slowly, not much drivers at a time, it's easier to recover an issue when you don't remove many modules from many categories
  • using genkernel all without cleaning, a new kernel can be out in a minute which make the process a lot faster

You can do this without genkernel but if you are like me, using LVM over LUKS and that you need an initrd file, genkernel will just ease the process and generate the initird that you need.

9. Use binary packages §

If you use Gentoo you may want to have control over most of your packages, but some packages can be really long to compile without much benefit, or you may simply be fine using a binary package. Some packages have the suffix -bin to their name, meaning they won't require compilation.

There are a few well known packages such as firefox-bin, libreoffice-bin, rust-bin and even gentoo-kernel-bin! You can get a generic kernel pre-compiled :)

Gentoo wiki: Using distribution kernel

10. Create binary packages §

It is possible to create a binary package of every program you compile on Gentoo, this can be used for distributing packages on similar systems or simply make a backup of your packages. In some cases, the redistribution may not work if you are on a system with a different CPU generation or different hardware, this is pretty normal because you often define the variables to optimize as much as possible the code for your CPU and the binaries produced won't work on another CPU.

The guide from Gentoo will explain all you need to know about the binary packages and how to redistribute them, but the simplest config you need to start generating packages from emerge compilation is setting FEATURES="buildpkg" in your make.conf

Gentoo wiki: Binary package guide

11. Good make.conf defaults §

This is a chunk of my make.conf file that I find really useful. It accepts all licenses, make portage run with nice 15 to not disturb much a running system, make it compile with 12 threads, run up to 8 parallel package creation except if the load reach 10.

And it always create binary packages, so if you play with USE flags and revert, you will already have a binary package and this will avoid recompiling.

ACCEPT_LICENSE="-* @EULA @BINARY-REDISTRIBUTABLE"
PORTAGE_NICENESS=15
EMERGE_DEFAULT_OPTS="${EMERGE_DEFAULT_OPTS} --getbinpkg -j 8 -l 10 --keep-going y"
FEATURES="ccache buildpkg network-sandbox"
MAKEOPTS="-j12"

VIDEO_CARDS=yourcard
L10N=yourlang

Listing every system I used

Written by Solène, on 02 July 2021.
Tags: #linux #unix #bsd

Comments on Fediverse/Mastodon

1. Introduction §

Nobody asked for it but I wanted to share the list of the system I used in my life (on a computer) and a few words about them. This is obviously not very accurate but I'm happy to write it somewhere.

You may wonder why I did some choices in the past, I was young and with little experience in many of these experiments, a nice looking distribution was very appealing to me.

One has to know (or remember) that 10 years ago, Linux distributions were very different from one to another and it became more and more standardized over time. At the point that I don't consider distro hoping (the fact to switch from a distribution to another regularly) something interesting because most distributions are derivative from a main one and most will all have a systemd and same defaults.

Disclaimer: my opinions about each systems are personal and driven by feeling and memories, it may be totally inaccurate (outdated or damaged memories) or even wrong (misunderstanding, bad luck). If I had issues with a system this doesn't mean it is BAD and that you shouldn't use it, I recommend to make your opinion about them.

2. The list (alphabetically) §

This includes Linux distributions but also BSD or Solaris derived system.

2.1. Alpine §

  • Duration: a few hours
  • Role: workstation
  • Opinion: interesting but lack of documentation
  • Date of use: June 2021

I wanted to use it on my workstation but the documentation for full disk encryption and the documentation in general was outdated and not accurate so I gave up.

However the extreme minimalism is interesting and without full disk encryption it worked fine. It was surprising to see how packages were split in such small parts, I understand why it's used to build containers.

I really want to like it, maybe in a few years it will be mature enough.

2.2. BackTrack §

  • Duration: occasionally
  • Role: playing with wifi devices
  • Opinion: useful
  • Date of use: occasionally between 2006 and 2012

Worked well with a wifi dongle supporting monitor mode.

2.3. CentOS §

  • Duration: not much
  • Role: local server
  • Opinion: old packages
  • Date of use: 2014

Nothing much to say, I had to use it temporarily to try a program we where delivering to a client using Red Hat.

2.4. Crux §

  • Duration: a few months maybe
  • Role: workstation
  • Opinion: it was blazing fast to install
  • Date of use: around 2009

I don't remember much about it to be honest.

2.5. Debian §

  • Duration: multiple years
  • Role: workstation (at least 1 year accumulated) and servers
  • Opinion: I don't like it
  • Date of use: from 2006 to now

It's not really possible to do Linux without having to deal with Debian some day. It's quite working when installed but I always had painful time with upgrades. As for using it as a workstation, it was at a time of gnome 2 and software were already often obsolete so I was using testing.

2.6. DragonflyBSD §

  • Duration: months
  • Role: server and workstation
  • Opinion: interesting
  • Date of use: ~2009-2011

The system worked quite well, I had hardware compatibility issues at that time but it worked well for my laptop. HAMMER was stable when I used it on my server and I really enjoyed working with this file system, the server was my NAS and Mumble server at that time and it never failed me. I really think this make a good alternative to ZFS.

2.7. Edubuntu §

  • Duration: months
  • Role: laptop
  • Opinion: shame
  • Date of use: 2006

I was trying to be a good student at that time and it seemed Edubuntu was interesting, I didn't understand it was just an Ubuntu with a few packages pre-installed. It was installed on my very first laptop (a very crappy one but eh I loved it.).

2.8. Elementary §

  • Duration: months
  • Role: laptop
  • Opinion: good
  • Date of use: 2019-now

I have an old multimedia laptop (the case is falling apart) that runs Elementary OS, mainly for their own desktop environment Pantheon that I really like. The distribution itself is solid and well done, it never failed me even after major upgrades. I could do everything using the GUI. I would recommend like it to a Linux beginner or someone enjoying GUI tools.

2.9. EndeavourOS §

  • Duration: months
  • Role: testing stuff
  • Opinion: good project
  • Date of use: 2021

I never been into Arch but I got my first contact with EndeavourOS, a distribution based on Arch Linux that proposes an installer with many options to install Arch Linux, and also a few helper tools to manage your system. This is clearly and Arch Linux and they don't hide it, they just facilitate the use and administration of the system. I'm totally capable of installing Arch but I have to admit if I can save a lot of time to install it in a full disk encryption setup using a GUI I'm all for it. As an Arch Linux noob, the little "welcome" GUI provided by EndeavourOS was very useful to learn how to use the packages manager and a few other things. I'd totally recommend it over Arch Linux because it doesn't denature Arch while still providing useful additions.

2.10. Fedora §

  • Duration: months
  • Role: workstation
  • Opinion: hazardous
  • Date of use: 2006 and around 2014

I started with Fedora Core 6 in 2006, at that time it was amazing, they had many new software and up to date, the alternative was Debian or Mandrake (with Ubuntu not being very popular yet), I used it a long time. I used it again later but I stumbled on many quality issues and I don't have good memories about it.

2.11. FreeBSD §

  • Duration: years
  • Role: workstation, server
  • Opinion: pretty good
  • Date of use: 2009 to 2020

This is the first BSD I tried, I heard a lot about it so I downloaded the 3 or 5 CDs of the release with my 16 kB/s DSL line, burned CDs and installed it on my computer, the installer was proposing to install packages at that time but it was doing it in a crazy way, you had to switch CD a lot between the sets because sometimes the package was on CD 2 then CD 3 and CD 1 and CD 3 and CD2.... For some reasons, I destroyed my system a few times by mixing ports and packages which ended in dooming the system. I learned a lot from my destroy and retry method.

For my first job (I occupied for 10 years) I switched all the Debian servers to FreeBSD servers and started playing with Jails to provide security for web server. FreeBSD never let me down on servers. The most pain I have with FreeBSD is freebsd-update updating RCS tags so I had to merge sometimes a hundred of files manually... At the point I preferred reinstalling my servers (with salt stack) than upgrading.

On my workstation it always worked well. I regret packages quality can be inconsistent sometimes but I'm also part of the problem because I don't think I ever reported such issues.

2.12. Frugalware §

  • Duration: weeks
  • Role: workstation
  • Opinion: I can't remember
  • Date of use: 2006?

I remember I've run a computer with that but that's all...

2.13. Gentoo §

  • Duration: months
  • Role: workstation
  • Opinion: i love it
  • Date of use: 2005, 2017, 2020 to now

My first encounter with Gentoo was at my early Linux discovery. I remember following the instructions and compiling X for like A DAY to get a weird result, the resolution was totally wrong and it was in grey scale so I gave up.

I tried it later in 2017 and I successfully installed it with full disk encryption and used it as my pro laptop, I don't remember I broke it once. The only issue was to wait the compilation time when I needed a program not installed.

I'm back on Gentoo regularly for one laptop that requires many tweaks to work correctly and I also use it as my main Linux at home.

2.14. gNewSense §

  • Duration: months
  • Role: workstation
  • Opinion: it worked
  • Date of use: 2006

It was my first encounter with a 100% free system, I remember it wasn't able to play MP3 files :) It was an Ubuntu derivative and the community was friendly. I see the project is abandoned now.

2.15. Guix §

  • Duration: months
  • Role: workstation
  • Opinion: interesting ideas but raw
  • Date of use: 2016 and 2021

I like Guix a lot, it has very good ideas and the consistent use of Scheme language to define the packages and write the tools is something I enjoy a lot. However I found the system doesn't feel very great for a desktop usage with GUI, it appears quite raw and required me many workaround to work correctly.

Note that Guix is a distribution but also the package manager that can be installed on any linux distribution in addition to the original package manager, in that case we refer to it as Foreign Guix.

2.16. Mandrake §

  • Duration: weeks?
  • Role: workstation
  • Opinion: one of my first
  • Date of use: 2004 or something

This was one of my first distribution and it came with a graphical installer! I remember packages had to be installed with the command "urpmi" but that's all. I think I didn't have access to the internet using my USB modem so I was limited to packages from the CDs I burned.

2.17. NetBSD §

  • Duration: years
  • Role: workstation and server
  • Opinion: good
  • Date of use: 2009 to 2015

I used NetBSD at first on a laptop (in 2009) but it was not very stable and programs were core dumping a lot, I found the software where not really up to date in pkgsrc too. However, I used it for years as my first email server and I never had a single issue.

I didn't try it seriously for a workstation recently but from what I've heard it became a good choice for a daily driver.

2.18. NixOS §

  • Duration: years
  • Role: workstation and server
  • Opinion: awesome but different
  • Date of use: 2016 to now

I use NixOS daily in my professional workstation since 2020, it never failed me even when I'm on the development channel. I already wrote about it, it's an amazing piece of work but is radically different from other Linux distributions or Unix-like systems.

I'm using it on my NAS and it's absolutely flawless since I installed it. But I am not sure how easy or hard it would be to run a full featured mail server on it (my best example for a complex setup).

2.19. NuTyX §

  • Duration: months
  • Role: workstation
  • Opinion: it worked
  • Date of use: 2010

I don't remember much about this distribution but I remember the awesome community and the creator of the distro which is a very helpful and committed person. This is a distribution made from scratch that is working very well and is still alive and dynamic, kudos to the team.

2.20. OpenBSD §

  • Duration: years
  • Role: workstation and server
  • Opinion: boring because it just works
  • Date of use: 2015 to now

I already wrote a few times why I like OpenBSD so I will make it short, it just works and it works fine. However the hardware compatibility can be limited, but when hardware is supported everything just work out of the box without any tweak.

I've been using it daily for years now and it started when my NetBSD mail server had to be replaced by a newer machine at online so I chose to try OpenBSD. I'm part of the team since 2018 and apart from occasional ports changes my big contribution was to setup the infrastructure to build binary packages for ports changes in the stable branch.

I wish performance were better though.

2.21. OpenIndiana §

  • Duration: weeks
  • Role: workstation
  • Opinion: sadness but hope?
  • Date of use: 2019

I was a huge fan of OpenSolaris but Oracle killed it. OpenIndiana is the resurrection of the open source Solaris but is now a bit abandoned from contributors and the community isn't as dynamic as previously. Hardware support is lagging however the system performs very well and all Solaris features are still there if you know what to do with it.

I really hope for this project to get back on track again and being as dynamic as it used to be!

2.22. OpenSolaris §

  • Duration: years
  • Role: workstation
  • Opinion: sadness
  • Date of use: 2009-2010

I loved OpenSolaris, it was such an amazing system, every new release had a ton of improvements (packages updates, features, hardware support) and I really thought it would compete Linux at this rate. It was possible to get free CD over snail mail and they looked amazing.

It was my main workstation on my big computer (I built it in 2007 and it had 2 xeon E5420 CPU and 32 GB of memory with 6x 500GB of SATA drives!!!), it was totally amazing to play with virtualization on it. The desktop was super fast and using Wine I was able to play Windows video games.

2.23. OpenSuse §

  • Duration: months
  • Role: pro workstation
  • Opinion: meh
  • Date of use: something like 2015

I don't have strong memories about OpenSuse, I think it worked well on my workstation at first but after some time I had some madness with the package manager that was doing weird things like removing half the packages to reinstall them... I never wanted to give another try after this few months experiment.

2.24. Paldo §

  • Duration: weeks? months?
  • Role: workstation
  • Opinion: the install was fast
  • Date of use: 2008?

I remember having played and contributed a bit to packages on IRC, all I remember is the kind community and that it was super fast to install. It's a distribution from scratch and it still alive and updated, bravo!

2.25. PC-BSD §

  • Duration: months
  • Role: workstation
  • Opinion: many attempts, too bad
  • Date of use: 2005-2017

PC-BSD (and more recently TrueOS) was the idea to provide FreeBSD to everyone. Each release was either good or bad, it was possible to use FreeBSD packages but also "pbi" packages that looked like Mac OS installers (a huge file that you had to double click on it to install). I definitely liked it because it was my first real success with FreeBSD but sometimes the tools proposed were half backed or badly documented. The project is dead now.

2.26. PCLinuxOS §

  • Duration: weeks?
  • Role: laptop
  • Opinion: it worked
  • Date of use: around 2008?

I remember installing it was working fine and I liked it.

2.27. Pop!_OS §

  • Duration: months
  • Role: gaming computer
  • Opinion: works!!
  • Date of use: 2020-2021

I use this distribution on my gaming computer and I have to admit it can easily replace Windows! :) Upgrades are painless and everything works out of the box (including the Nvidia driver).

2.28. Scientific Linux §

  • Duration: months
  • Role: workstation
  • Opinion: worked well
  • Date of use: ??

I remember I used scientific Linux as my main distribution at work for some time, it worked well and remembered me my old Fedora Core.

2.29. Skywave §

  • Duration: occasionally
  • Role: laptop for listening to radio waves
  • Opinion: a must
  • Date of use: 2018-now

This distribution is really focused into providing tools for using radio hardware, I bought a simple and cheap RTL-SDR usb device and I've been able to use it with pre-installed software. Really a plug and play experience. It works as a live CD so you don't even need to install it to benefit from its power.

2.30. Slackware §

  • Duration: years
  • Role: workstation and server
  • Opinion: Still Loving You....
  • Date of use: multiple times since 2002

It is very hard for me to explain how much and deep I love Slackware Linux. I just love it. In the date you can read I started with it in 2002, it's my very first encounter with Linux. A friend bought a Linux Magazine with Slackware CDs and explanations about the installation, it worked and many programs were available to play with! (I also erased Windows on the family computer because I had no idea what I was doing).

Since that time, I used Slackware multiples times and I think it's the system that survived the longest time every time it got installed, every new Slackware release was a day to celebrate for me.

I can't explain why I like it so much, I guess it's because you deeply know how your system work over time. Packages didn't manage dependencies at that time and it was a real pain to get new programs, it improved a lot now.

I really can't wait Slackware 15.0 to be out!

2.31. Solaris §

  • Duration: months
  • Role: workstation
  • Opinion: fine but not open source
  • Date of use: 2008

I remember the first time I heard that Solaris was a system I could install on my machine, I started to install it after downloading 2 parts of the ISO (which had to be joined using cat), I started to install it on my laptop and went to school with the laptop on battery continuing installing (it was very long) and ending the installation process in class (I was in a computer science university so it was fine :P ).

I discovered a whole new world with it, I even used it on a netbook to write some Java SCTP university project. It was the very introduction to ZFS, brand new FS with many features.

2.32. Solus §

  • Duration: days
  • Role: workstation
  • Opinion: good job team
  • Date of use: 2020

I didn't try much Solus because I'm quite busy nowadays, but it's a good distro as an alternative to major distributions, it's totally independent from other main projects and they even have their own package manager. My small experiment was good and it felt quality, it's a rolling release model but the packages are curated to check quality before being pushed to mass users.

I wish them a long and prosper life.

2.33. Ubuntu §

  • Duration: months
  • Role: workstation and server
  • Opinion: it works fine
  • Date of use: 2006 to 2014

I used Ubuntu on laptop a lot, and I recommended many people to use Ubuntu if they wanted to try Linux. Whatever we say, they helped to get Linux known and bring Linux to masses. Some choices like non-free integration are definitely not great though. I started with Dapper Drake (Ubuntu 6.06 !) on an old Pentium 1 server I had under my dresser in my student room.

I used it daily a few times but mainly at the time the default window manager was Unity. For some reasons, I loved Unity, it's really a pity the project is now abandoned and lost, it worked very well for me and looked nice.

I don't want to use it anymore as it became very complex internally, like trying to understand how domain names are resolved is quite complicated...

2.34. Void §

  • Duration: days?
  • Role: workstation
  • Opinion: interesting distribution, not enough time to try
  • Date of use: 2018

Void is an interesting distribution, I use it a little on a netbook with their musl libc edition and I've run into many issues at usage but also at install time. The glibc version was working a lot better but I can't remember why it didn't catch me more than this.

I wish I could have a lot of time to try it more seriously. I recommend everyone giving it a try.

2.35. Windows §

  • Duration: years
  • Role: gaming computer
  • Opinion: it works
  • Date of use: 1995 to now

My first encounter with a computer was with Windows 3.11 on a 486dx computer, I think I was 6. Since then I always had a Windows computer, at first because I didn't know there were alternatives and then because I always had it as a hard requirement for a hardware, a software or video games. Now, my gaming computer is running Windows and is dedicated to games only, I do not trust this system enough to do anything else. I'm slowly trying to move away from it and efforts are giving results, more and more games works fine on Linux.

2.36. Zenwalk §

  • Duration: months
  • Role: workstation
  • Opinion: it's like slackware but lighter
  • Date of use: 2009?

I don't remember much, it was like Slackware but without the giant DVD install that requires 15GB of space for installation, it used Xfce by default and looked nice.

How to choose a communication protocol

Written by Solène, on 25 June 2021.
Tags: #internet

Comments on Fediverse/Mastodon

1. Introduction §

As a human being I have to communicate with other people and now we have many ways to speak to each other, so many that it's hard to speak to other people. This is a simple list of communication protocol and why you would use them. This is an opinionated text.

2. Protocols §

We rely on protocols to speak to each other, the natural way would be language with spoken words using vocal chords, we could imagine other way like emitting sound in Morse. With computers we need to define how to send a message from A to B and there are many many possibilities for such a simple task.

  • 1. The protocol could be open source, meaning anyone can create a client or a server for this protocol.
  • 2. The protocol can be centralized, federated or peer to peer. In a centralized situation, there is only one service provider and people must be on the same server to communicate. In a federated or peer-to-peer architecture, people can join the communication network with their own infrastructure, without relying on a service provider (federated and peer to peer are different in implementation but their end result is very close)
  • 3. The protocol can provide many features in addition to contact someone.

2.1. IRC §

The simplest communication protocol and an old one. It's open source and you can easily host your own server. It works very well and doesn't require a lot of resources (bandwidth, CPU, memory) to run, although it is quite limited in features.

  • you need to stay connected to know what happen
  • you can't stay connected if you don't keep a session opened 24/7
  • multi device (computer / phone for instance) is not possible without an extra setup (bouncer or tmux session)

I like to use it to communicate with many people on some topic, I find they are a good equivalent of forums. IRC has a strong culture and limitations but I love it.

2.2. XMPP (ex Jabber) §

Behind this acronym stands a long lived protocol that supports many features and has proven to work, unfortunately the XMPP clients never really shined by their user interface. Recently the protocol is seeing a good adoption rate, clients are getting better, servers are easy to deploy and doesn't draw much resources (i/o, CPU, memory).

XMPP uses a federation model, anyone can host their server and communicate with people from other servers. You can share files, create rooms, do private messages. Audio and video is supported based on the client. It's also able to bridge to IRC or some other protocol using the correct software. Multiples options for end-to-end encryption are available but the most recent named OMEMO is definitely the best choice.

The free/open source Android client « Conversations » is really good, on a computer you can use Gajim or Dino with a nice graphical interface, and finally profanity or poezio for a console client.

XMPP on Wikipedia

2.3. Matrix §

Matrix is a recent protocol in the list although it saw an incredible adoption rate and since the recent Freenode drama many projects switched to their own Matrix room. It's fully open source in client or servers and is federated so anyone can be independent with their own server.

As it's young, Matrix has only one client that proposes all the features which is Element, a very resource hungry web program (web page or run "natively using Electron, a program to turn website in desktop application) and a python server named Synapse that requires a lot of CPU to work correctly.

In regards to features, Matrix proposes end to end encryption, rooms, direct chat, encryption done well, file sharing, audio/video etc...

While it's a good alternative to XMPP, I prefer XMPP because of the poor choice of clients and servers in Matrix at the moment. Hopefully it may get better in the future.

Matrix protocol on Wikipedia

2.4. Email §

This way is well known, most people have an email address and it may have been your first touch with the Internet. Email works well, it's federated and anyone can host an email server although it's not an easy task.

Mails are not instant but with performant servers it can only takes a few seconds for an email to be sent and delivered. They can support end to end encryption using GPG which is not always easy to use. You have a huge choice for email clients and most of them allow incredible settings choice.

I really like emails, it's a very practical way to communicate ideas or thoughts to someone.

2.4.1. Delta Chat §

I found a nice program named Delta Chat that is built on top of emails to communicate "instantly" with your friends who also use Delta Chat, messages are automatically encrypted.

The client user interface looks like an instant messaging program but will uses emails to transport the messages. While the program is open source and Free, it requires electron for desktop and I didn't find a way to participate to an encrypted thread using an email client (even using the according GPG key). I really found that software practical because your recipients doesn't need to create a new account, it will reuse an existing email address. You can also use it without encryption to write to someone who will reply using their own mail client but you use delta chat.

Delta Chat website

2.5. Telegram §

Open source client but proprietary server, I don't recommend anyone to use such a system that lock you to their server. You would have to rely on a company and you empower them by using their service.

Telegram on Wikipedia

2.6. Signal §

Open source client / server but the main server where everybody is doesn't allow federation. So far, hosting your own server doesn't seem a possible and viable solution. I don't recommend using it because you rely on a company offering a service.

Signal on Wikipedia

2.7. WhatsApp §

Proprietary software and service, please don't use it.

3. Conclusion §

I daily use IRC, Emails and XMPP to communicate with friends, family, crew from open source projects or meet new people sharing my interests. My main requirement for private messages is end to end encryption and being independent so I absolutely require federated protocol.

How to use the Open Graph Protocol for your website

Written by Solène, on 21 June 2021.
Tags: #blog

Comments on Fediverse/Mastodon

1. Introduction §

Today I made a small change to my blog, I added some more HTML metadata for the Open Graph protocol.

Basically, when you share an url in most social networks or instant messaging, when some Open Graph headers are present the software will display you the website name, the page title, a logo and some other information. Without that, only the link will be displayed.

2. Implementation §

You need to add a few tags to your HTML pages in the "head" tag.

    <meta property="og:site_name" content="Solene's Percent %" />
    <meta property="og:title"     content="How to cook without burning your eyebrows" />
    <meta property="og:image"     content="static/my-super-pony-logo.png" />
    <meta property="og:url"       content="https://dataswamp.org/~solene/some-url.html" />
    <meta property="og:type"      content="website" />
    <meta property="og:locale"    content="en_EN" />

There are more metadata than this but it was enough for my blog.

Open Graph Protocol website

Using the I2P network with OpenBSD and NixOS

Written by Solène, on 20 June 2021.
Tags: #i2p #tor #openbsd #nixos #networking

Comments on Fediverse/Mastodon

1. Introduction §

In this text I will explain what is the I2P network and how to provide a service over I2P on OpenBSD and how to use to connect to an I2P service from NixOS.

2. I2P §

This acronym stands for Invisible Internet Project and is a network over the network (Internet). It is quite an old project from 2003 and is considered stable and reliable. The idea of I2P is to build a network of relays (people running an i2p daemon) to make tunnels from a client to a server, but a single TCP session (or UDP) between a client and a server could use many tunnels of n hops across relays. Basically, when you start your I2P service, the program will get some information about the relays available and prepare many tunnels in advance that will be used to reach a destination when you connect.

Some benefits from I2P network:

  • your network is reliable because it doesn't take care of operator peering
  • your network is secure because packets are encrypted, and you can even use usual encryption to reach your remote services (TLS, SSH)
  • provides privacy because nobody can tell where you are connecting to
  • can prevent against habits tracking (if you also relay data to participate to i2p, bandwidth allocated is used at 100% all the time, and any traffic you do over I2P can't be discriminated from standard relay!)
  • can only allow declared I2P nodes to access a server if you don't want anyone to connect to a port you expose

It is possible to host a website on I2P (by exposing your web server port), it is called an eepsite and can be accessed using the SOCKs proxy provided by your I2P daemon. I never played with them though but this is a thing and you may be interested into looking more in depth.

I2P project and I2P implementation (java) page

i2pd project (a recent C++ implementation that I use for this tutorial)

Wikipedia page about I2P

3. I2P vs Tor §

Obviously, many people would question why not using Tor which seems similar. While I2P can seem very close to Tor hidden services, the implementation is really different. Tor is designed to reach the outside while I2P is meant to build a reliable and anonymous network. When started, Tor creates a path of relays named a Circuit that will remain static for an approximate duration of 12 hours, everything you do over Tor will pass through this circuit (usually 3 relays), on the other hand I2P creates many tunnels all the time with a very low lifespan. Small difference, I2P can relay UDP protocol while Tor only supports TCP.

Tor is very widespread and using a tor hidden service for hosting a private website (if you don't have a public IP or a domain name for example) would be better to reach an audience, I2P is not very well known and that's partially why I'm writing this. It is a fantastic piece of software and only require more users.

Relays in I2P doesn't have any weight and can be seen as a huge P2P network while Tor network is built using scores (consensus) of relaying servers depending of their throughput and availability. Fastest and most reliable relays will be elected as "Guard server" which are entry points to the Tor network.

I've been running a test over 10 hours to compare bandwidth usage of I2P and Tor to keep a tunnel / hidden service available (they have not been used). Please note that relaying/transit were desactivated so it's only the uploaded data in order to keep the service working.

  • I2P sent 55.47 MB of data in 114 430 packets. Total / 10 hours = 1.58 kB/s average.
  • Tor sent 6.98 MB of data in 14 759 packets. Total / 10 hours = 0.20 kB/s average.

Tor was a lot more bandwidth efficient than I2P for the same task: keeping the network access (tor or i2p) alive.

4. Quick explanation about how it works §

There are three components in an I2P usage.

- a computer running an I2P daemon configured with tunnels servers (to expose a TCP/UDP port from this machine, not necessarily from localhost though)

- a computer running an I2P daemon configured with tunnel client (with information that match the server tunnel)

- computers running I2P and allowing relay, they will receive data from other I2P daemons and pass the encrypted packets. They are the core of the network.

In this text we will use an OpenBSD system to share its localhost ssh access over I2P and a NixOS client to reach the OpenBSD ssh port.

5. OpenBSD §

The setup is quite simple, we will use i2pd and not the i2p java program.

pkg_add i2pd

# read /usr/local/share/doc/pkg-readmes/i2pd for open files limits

cat <<EOF > /etc/i2pd/tunnels.conf
[SSH]
type = server
port = 22
host = 127.0.0.1
keys = ssh.dat
EOF

rcctl enable i2pd
rcctl start i2pd

You can edit the file /etc/i2pd/i2pd.conf to uncomment the line "notransit = true" if you don't want to relay. I would encourage people to contribute to the network by relaying packets but this would require some explanations about a nice tuning to limit the bandwidth correctly. If you disable transit, you won't participate into the network but I2P won't use any CPU and virtually no data if your tunnel is in use.

Visit http://localhost:7070/ for the admin interface and check the menu "I2P Tunnels", you should see a line "SSH => " with a long address ending by .i2p with :22 added to it. This is the address of your tunnel on I2P, we will need it (without the :22) to configure the client.

6. Nixos §

As usual, on NixOS we will only configure the /etc/nixos/configuration.nix file to declare the service and its configuration.

We will name the tunnel "ssh-solene" and use the destination seen on the administration interface on the OpenBSD server and expose that port to 127.0.0.1:2222 on our NixOS box.

services.i2pd.enable = true;
services.i2pd.notransit = true;

services.i2pd.outTunnels = {
  ssh-solene = {
    enable = true;
    name = "ssh";
    destination = "gajcbkoosoztqklad7kosh226tlt5wr2srr2tm4zbcadulxw2o5a.b32.i2p";
    address = "127.0.0.1";
    port = 2222;
    };
};

Now you can use "nixos-rebuild switch" as root to apply changes.

Note that the equivalent NixOS configuration for any other OS would look like that for any I2P setup in the file "tunnel.conf" (on OpenBSD it would be in /etc/i2pd/tunnels.conf).

[ssh-solene]
type = client
address = 127.0.0.1  # optional, default is 127.0.0.1
port = 2222
destination = gajcbkoosoztqklad7kosh226tlt5wr2srr2tm4zbcadulxw2o5a.b32.i2p

7. Test the setup §

From the NixOS client you should be able to run "ssh -p 2222 localhost" and get access to the OpenBSD ssh server.

Both systems have a http://localhost:7070/ interface because it's a default setting that is not bad (except if you have multiple people who can access the box).

8. Conclusion §

I2P is a nice way to share services on a reliable and privacy friendly network, it may not be fast but shouldn't drop you when you need it. Because it can easily bypass NAT or dynamic IP it's perfectly fine for a remote system you need to access when you can use NAT or VPN.

Run your Gemini server on Guix with Agate

Written by Solène, on 17 June 2021.
Tags: #guix #gemini

Comments on Fediverse/Mastodon

1. Introduction §

This article is about deploying the Gemini server agate on the Guix linux distribution.

Gemini quickstart to explain Gemini to beginners

Guix website

2. Configuration §

Guix manual about web services, search for Agate.

Add the agate-service definition in your /etc/config.scm file, we will store the Gemini content in /srv/gemini/content and store the certificate and its private key in the upper directory.

(service agate-service-type
         (agate-configuration
          (content "/srv/gemini/content")
          (cert "/srv/gemini/cert.pem")
          (key "/srv/gemini/key.rsa"))

If you have something like %desktop-services or %base-services, you need to wrap the services list a list using "list" function and add the %something-services to that list using the function "append" like this.

(services
  (append
    (list (service openssh-service-type)
          (service agate-service-type
                   (agate-configuration
                    (content "/srv/gemini/content")
                    (cert "/srv/gemini/cert.pem")
                    (key "/srv/gemini/key.rsa"))))
    %desktop-services))

3. Generating the certificate §

- Create directories /srv/gemini/content

- run the following command in /srv/gemini/

openssl req -x509 -newkey rsa:4096 -keyout key.rsa -out cert.pem -days 3650 -nodes -subj "/CN=YOUR_DOMAIN.TLD"

- Apply a chmod 400 on both files cert.pem and key.rsa

- Use "guix system reconfigure /etc/config.scm" to install agate

- Use "chown agate:agate cert.pem key.rsa" to allow agate user to read the certificates

- Use "herd restart agate" to restart the service, you should have a working gemini server on port 1965 now

4. Conclusion §

You are now ready to publish content on Gemini by adding files in /srv/gemini/content , enjoy!

How to use Tor only for onion addresses in a web browser

Written by Solène, on 12 June 2021.
Tags: #tor #openbsd #networking #security #privacy

Comments on Fediverse/Mastodon

1. Introduction §

A while ago I published about Tor and Tor hidden services. As a quick reminder, hidden services are TCP ports exposed into the Tor network using a long .onion address and that doesn't go through an exit node (it never leaves the Tor network).

If you want to browse .onion websites, you should use Tor, but you may not want to use Tor for everything, so here are two solutions to use Tor for specific domains. Note that I use Tor but this method works for any Socks proxy (including ssh dynamic tunneling with ssh -D).

I assume you have tor running and listening on port 127.0.0.1:9050 ready to accept connections.

2. Firefox extension §

The easiest way is to use a web browser extension (I personally use Firefox) that will allow defining rules based on URL to choose a proxy (or no proxy). I found FoxyProxy to do the job, but there are certainly other extensions that propose the same features.

FoxyProxy for Firefox

Install that extension, configure it:

- add a proxy of type SOCKS5 on ip 127.0.0.1 and port 9050 (adapt if you have a non standard setup), enable "Send DNS through SOCKS5 proxy" and give it a name like "Tor"

- click on Save and edit patterns

- Replace "*" by "*.onion" and save

In Firefox, click on the extension icon and enable "Proxies by pattern and order" and visit a .onion URL, you should see the extension icon to display the proxy name. Done!

3. Using privoxy §

Privoxy is a fantastic tool that I forgot over the time, it's an HTTP proxy with built-in filtering to protect users privacy. Marcin Cieślak shared his setup using privoxy to dispatch between Tor or no proxy depending on the url.

The setup is quite easy, install privoxy and edit its main configuration file, on OpenBSD it's /etc/privoxy/config, and add the following line at the end of the file:

forward-socks4a   .onion               127.0.0.1:9050 .

Enable the service and start/reload/restart it.

Configure your web browser to use the HTTP proxy 127.0.0.1:8080 for every protocol (on Firefox you need to check a box to also use the proxy for HTTPS and FTP) and you are done.

Marcin Cieślak mastodon account (thanks for the idea!).

4. Conclusion §

We have seen two ways to use a proxy depending on the location, this can be quite useful for Tor but also for some other use cases. I may write about privoxy in the future but it has many options and this will take time to dig that topic.

5. Going further §

Duckduck Go official Tor hidden service access

Check if you use Tor, this is a simple but handy service when you play with proxies

Official Duckduck Go about their Tor hidden service

6. TL;DR on OpenBSD §

If you are lazy, here are instructions as root to setup tor and privoxy on OpenBSD.

pkg_add privoxy tor
echo "forward-socks4a   .onion               127.0.0.1:9050 ." >> /etc/privoxy/config
rcctl enable privoxy tor
rcctl start privoxy tor

Tor may take a few minutes the first time to build a circuit (finding other nodes).

Guix: easily run Linux binaries

Written by Solène, on 10 June 2021.
Tags: #guix

Comments on Fediverse/Mastodon

1. Introduction §

For those who used Guix or Nixos you may know that running a binary downloaded from the internet will fail, this is because most expected paths are different than the usual Linux distributions.

I wrote a simple utility to help fixing that, I called it "guix-linux-run", inspired by the "steam-run" command from NixOS (although it has no relation to Steam).

Gitlab project guix-linux-run

2. How to use §

Clone the git repository and make the command linux-run executable, install packages gcc-objc++:lib and gtk+ (more may be required later).

Call "~/guix-linux-run/linux-run ./some_binary" and enjoy.

If you get an error message like "libfoobar" is not available, try to install it with the package manager and try again, this is simply because the binary is trying to use a library that is not available in your library path.

In the project I wrote a simple compatibility list from a few experiments, unfortunately it doesn't run everything and I still have to understand why, but it permitted me to play a few games from itch.io so it's a start.

Guix: fetch packages from other Guix in the LAN

Written by Solène, on 07 June 2021.
Tags: #guix

Comments on Fediverse/Mastodon

1. Introduction §

In this how-to I will explain how to configure two Guix system to share packages from one to another. The idea is that most of the time packages are downloaded from ci.guix.gnu.org but sometimes you can compile local packages too, in both case you will certainly prefer computers from your network to get the same packages from a computer that already had them to save some bandwidth. This is quite easy to achieve in Guix.

We need at least two Guix systems, I'll name the one with the package "server" and the system that will install packages the "client".

2. Prepare the server §

On the server, edit your /etc/config.scm file and add this service:

(service guix-publish-service-type
         (guix-publish-configuration
             (host "0.0.0.0")
             (port 8080)
             (advertise? #t))))

Guix Manual: guix-publish service

Run "guix archive --generate-key" as root to create a public key and then reconfigure the system. Your system is now publishing packages on port 8080 and advertising it with mDNS (involving avahi).

Your port 8080 should be reachable now with a link to a public key.

3. Prepare the client §

On the client, edit your /etc/config.scm file and modify the "%desktop-services" or "%base-services" if any.

(guix-service-type
  config =>
    (guix-configuration
      (inherit config)
      (discover? #t)
      (authorized-keys
        (append (list (local-file "/etc/key.pub"))
                %default-authorized-guix-keys)))))))

Guix Manual: Getting substitutes from other servers

Download the public key from the server (visiting its ip on port 8080 you will get a link) and store it in "/etc/key.pub", reconfigure your system.

Now, when you install a package, you should see from where the substitution (name for packages) are downloaded from.

4. Declaring a repository (not dynamic) §

In the previous example, we are using advertising on the server and discovery on the client, this may not be desired and won't work from a different network.

You can manually register a remote substitute server instead of using discovery by using "substitute-urls" like this:

(guix-service-type
  config =>
    (guix-configuration
      (inherit config)
      (discover? #t)
      (substitute-urls
        (append (list "http://192.168.1.66:8080")
                %default-substitute-urls))
      (authorized-keys
        (append (list (local-file "/etc/key.pub"))
                %default-authorized-guix-keys)))))))

5. Conclusion §

I'm doing my best to avoid wasting bandwidth and resources in general, I really like this feature because this doesn't require much configuration or infrastructure and work in a sort of peer-to-peer.

Other projects like Debian prefer using a proxy that keep in cache the packages downloaded and act as a repository provider itself to proxyfi the service.

In case of doubts of the validity of the substitutions provided by an url, the challenge feature can be used to check if reproducible builds done locally match the packages provided by a source.

Guix Manual: guix challenge documentation

Guix Manual: guix weather, a command to get information from a repository

GearBSD: managing your packages on OpenBSD

Written by Solène, on 02 June 2021.
Tags: #rex #openbsd #gearbsd

Comments on Fediverse/Mastodon

1. Introduction §

I added a new module for GearBSD, it allows to define the exact list of packages you want on the system and GearBSD will take care of removing extra packages and installing missing packages. This is a huge step for me to allow managing the system from code.

Note that this is an improvement over feeding pkg_add with a package list because this method doesn't remove extra packages.

GearBSD packages in action on asciinema

2. How to use §

In the directory openbsd/packages/ of the GearBSD git repository, edit the file Rexfile and list the packages you want in the variable @packages.

This is the packages set I want on my server.

my @packages = qw/
bwm-ng checkrestart colorls curl dkimproxy dovecot dovecot-pigeonhole
duplicity ecl geomyidae git gnupg go-ipfs goaccess kermit lftp mosh
mtr munin-node munin-server ncdu nginx nginx-stream
opensmtpd-filter-spamassassin p5-Mail-SpamAssassin  postgresql-server
prosody redis rss2email rsync
/;

Then, run "rex -h localhost show" to see what changes will be done like which packages will be removed and which packages will be installed.

Run "rex -h localhost configure" to apply the changes for real. I use "rex -h localhost" using a local ssh connection to root but you could run rex as root with doas with the same effect.

3. How does it work §

Installing missing packages was easy but removing extra packages was harder because you could delete packages that are still required as dependencies.

Basically, the module looks at the packages you manually installed (the one you directly installed with the pkg_add command), if they are not part of your list of packages you want to have installed, they are marked as automatically installed and then "pkg_delete -a" will remove them if they are not required by any other package.

4. Where is going GearBSD §

This is a project I started yesterday but I've long think about it. I really want to be able to manage my OpenBSD system with a single configuration file. I currently wrote two modules that are independently configured, the issue is that it doesn't allow altering modules from one to another.

For example, if I create a module to install gnome3 and configure it correctly, this will require gnome3 and gnome3-packages but if you don't have them in your packages list, it will get deleted. GearBSD needs a single configuration file with all the information required by all packages, this will permit something like this:

$module{pf}{TCPports} = [ 22 ];
$module{gnome}{enable} = 1;
$module{gnome}{lang} = "fr_FR.UTF-8";
@packages = qw/catgirl firefox keepassxc/;

The module gnome will know it's enabled and that @packages has to receive gnome3 and gnome3-extras packages in order to work.

Such main configuration file will allow to catch incompatibilities like enabling gdm and xenodm at the same time.

GearBSD: a project to help automating your OpenBSD

Written by Solène, on 01 June 2021.
Tags: #gearbsd #rex #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

I love NixOS and Guix for their easy system configuration and easy jumping from one machine to another by using your configuration file. To some extent, I want to make it possible to do so on OpenBSD with a collection of parametrized Rex modules, allowing to configure your system piece by piece from templates that you feed with variables.

Let me introduce you to GearBSD, my project to do so.

GearBSD gitlab page

2. How to use §

You need to clone https://tildegit.org/solene/gearbsd using git and you also need to install Rex with pkg_add p5-Rex.

Use cd to enter into a directory like openbsd/pf (the only one module at this time), edit the Rexfile to change the variables as you want and run "doas rex configure" to apply.

Video example (asciinema recording)

3. Example with PF §

The PF module has a few variables, in TCPports and UDPports you can list ports or ports ranges that will be allowed, if no ports are in the list then the "pass" rules for that protocol won't be there.

If you want to enable nat on em0 for your wg0 interface, set "nat" to 1, "nat_from_interface" to "wg0" and "nat_to_interface" to "em0" and the code will take care of everything, even enabling the sysctl for port forwarding.

4. More work required §

It's only a start but I want to work hard on it to make OpenBSD a more accessible system for everyone, and more pleasant to use.

(R)?ex automation for deploying Matrix synapse on OpenBSD

Written by Solène, on 31 May 2021.
Tags: #rex #matrix #openbsd

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1. Introduction §

Today I will introduce you to Rex, an automation tool written in Perl and using SSH, it's an alternative to Salt, Ansible or drist.

(R)?ex project website

2. Setup §

You need to install Rex on the management system, this can be done using cpan or your package manager, on OpenBSD you can use "pkg_add p5-Rex" to install it. You will get an executable script named "rex".

To make things easier, we will use ssh from the management machine (your own computer) and a remote server, using your ssh key to access the root account (escalation with sudo is possible but will complicate things).

Get Rex

3. Simple steps §

Create a text file named "Rexfile" in a directory, this will contain all the instructions and tasks available.

We will write in it that we want the features up to the syntax version 1.4 (latest at this time, doesn't change often), the default user to connect to remote host will be root and our servers group has only one address.

use Rex -feature => ['1.4'];

user "root";
group servers => "myremoteserver.com";

We can go further now.

4. Rex commands cheat sheet §

Here are some commands, you don't need much to use Rex.

- rex -T : display the list of tasks defined in Rexfile

- rex -h : display help

- rex -d : when you need some debug

- rex -g : run a task on group

5. Installing Munin-master §

An example I like is deploying Munin on a computer, it requires a cron and a package.

The following task will install a package and add a crontab entry for root.

desc "Munin-cron installation";
task "install_munin_cron", sub {
	pkg "munin-server", ensure => "present";
	
	cron add => "root", {
		ensure => "present",
		command = > "su -s /bin/sh _munin /usr/local/bin/munin-cron",
		on_change => sub {
			say "Munin cron modified";
		}
	};
};

Now, let's say we want to configure this munin cron by providing it a /etc/munin/munin.conf file that we have locally. This can be done by adding the following code:

	file "/etc/munin/munin.conf",
	source => "local_munin.conf",
	owner => "root",
	group => "wheel",
	mode => 644,
	on_change => sub {
		say "munin.conf has been modified";
	};

This will install the local file "local_munin.conf" into "/etc/munin/munin.conf" on the remote host, owned by root:wheel with a chmod 644.

Now you can try "rex -g servers install_munin_cron" to deploy.

6. Real world tasks §

6.1. Configuring PF §

This task deploys a local pf.conf file into /etc/pf.conf and reload the configuration on changes.

desc "Configuration PF";
task "prepare_pf", sub {

    file "/etc/pf.conf",
    source => "pf.conf",
    owner => "root",
    group => "wheel",
    mode => 400,
    on_change => sub {
        say "pf.conf modified";
        run "Restart pf", command => "pfctl -f /etc/pf.conf";
    };
};

6.2. Deploying Matrix Synapse §

A task can call multiples tasks for bigger deployments. In this one, we have a "synapse_deploy" task that will run synapse_install() and then synapse_configure() and synapse_service() and finally prepare_pf() to ensure the rules are correct.

As synapse will generate a working config file, there are no reason to push one from the local system.

desc "Deploy synapse";
task "synapse_deploy", sub {
    synapse_install();
    synapse_configure();
    synapse_service();
    prepare_pf();
};

desc "Install synapse";
task "synapse_install", sub {
    pkg "synapse", ensure => "present";
    
    run "Init synapse",
    	command => 'su -s /bin/sh _synapse -c "/usr/local/bin/python3 -m synapse.app.homeserver -c /var/synapse/
    	cwd => "/tmp/",
    	only_if => is_file("/var/synapse/homeserver.yaml");
};

desc "Configure synapse";
task "synapse_configure", sub {
    file "/etc/nginx/sites-enabled/synapse.conf",
    	source => "nginx_synapse.conf",
    	owner => "root",
    	group => "wheel",
    	mode => "444",
    	on_change => sub {
    		service nginx => "reload";
    	};
};

desc "Service for synapse";
task "synapse_service", sub {
    service synapse => "ensure", "started";
};

7. Going further §

Rex offers many feature because the configuration is real Perl code, you can make loops, conditions and extend Rex by writing local modules.

Instead of pushing configuration file from an hard coded local one, I could write a template of the configuration file and then use Rex to generate the configuration file on the fly by giving it the needed variables.

Rex has many functions to directly alter text files like "append-if_no_such_line" to add a line if it doesn't exist or replace/add/update a line matching a regex (can be handy to uncomment some lines).

Full list of Rex commands

Rex guides

Rex FAQ

8. Conclusion §

Rex is a fantastic tool if you want to programmaticaly configure a system, it can even be used for your local machine to allow reproducible configuration or for keeping track of all the changes in one place.

I really like it because it's simple to work with, it's Perl code doing real things, it's easy to hack on it (I contributed to some changes and the process was easy) and it only requires a working ssh toward a server (and Perl on the remote host). While Salt stack also works "agent less", it's painfully slow compared to Rex.

Kakoune: filetype based on filename

Written by Solène, on 30 May 2021.
Tags: #kakoune #editor

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1. Introduction §

I will explain how to configure Kakoune to automatically use a filetype (for completion/highlighting..) depending on the filename or its extension.

2. Setup §

The file we want to change is ~/.config/kak/kakrc , in case of issue you can use ":buffer *debug*" in kakoune to display the debug output.

2.1. Filetype based on the filename §

I had a case in which the file doesn't have any extension. This snippet will assign the filetype Perl to files named Rexfile.

hook global BufCreate (.*/)?Rexfile %{
	set buffer filetype perl
}

2.2. Filetype based on the extension §

While this is pretty similar to the previous example, we will only match any file ending by ".gmi" to assign it a type markdown (I know it's not but the syntax is quite similar).

hook global BufCreate .*\.gmi %{
	set buffer filetype markdown
}

Using dpb on OpenBSD for package compilation cluster

Written by Solène, on 30 May 2021.
Tags: #openbsd

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1. Introduction §

Today I will explain how to easily setup your own OpenBSD dpb infra. dpb is a tool to manage port building and can use chroot to use a sane environment for building packages.

This is particularly useful when you want to test packages or build your own, it can parallelize package compilation in two way: multiples packages at once and multiples processes for one package.

dpb man page

proot man page

The dpb and proot executable files are available under the bin directory of the ports tree.

Building your packages provide absolutely NOTHING compared to using binary packages except wasting CPU time, disk space and bandwidth.

2. Setup §

You need a ports tree and a partition that you accept to mount with wxallowed,nosuid,dev options. I use /home/ for that. To simplify the setup, we will create a chroot in /home/build/ and put our ports tree in /home/build/usr/ports (then your /usr/ports can be a symlink).

Create a text file that will be used as a configuration file for proot

chroot=/home/build
WRKOBJDIR=/tmp/pobj
LOCKDIR=/tmp/locks
PLIST_REPOSITORY=/data/plist
DISTDIR=/data/distfiles
PACKAGE_REPOSITORY=/data/packages
actions=unpopulate
sets=base comp etc xbase xfont xshare xetc xserver

This will tell proot to create a chroot in /home/build and preconfigure some variables for /etc/mk.conf, use all sets listed in "sets" and clean everything when run (this is what actions=unpopulate is doing). Running proot is as easy as "proot -c proot_config".

Then, you should be able to run "dpb -B /home/build/ some/port" and it will work.

3. Ease of use §

I wrote a script to clean locks from dpb, locks from ports system and pobj directories but also taking care of adding the mount options.

Options -p and -j will tell dpb how many cores can be used for parallel compilation, note that dpb is smart and if you tell it 3 ports in parallel and 3 threads in parallel, it won't use 3x3, it will compile three ports at a time and once it's stuck with only one port, it will add cores to its build to make it faster.

#!/bin/sh

CHROOT=/home/build/
CORES=3

rm -fr ${CHROOT}/usr/ports/logs/amd64/locks/*
rm -fr ${CHROOT}/tmp/locks/*
rm -fr ${CHROOT}/tmp/pobj/*
mount -o dev -u /home
mount -o nosuid -u /home
mount -o wxallowed -u /home
/usr/ports/infrastructure/bin/dpb -B $CHROOT -c -p $CORES -j $CORES  $*

Then I use "doas ./my_dpb.sh sysutils/p5-Rex lang/guile" to run the build process.

It's important to use -c in dpb command line which will clear compilation logs of the packages but retains the log size, this will be used to estimate further builds progress by comparing current log size with previous logs sizes.

You can harvest your packages from /home/build/data/packages/ , I even use a symlink from /usr/ports/packages/ to the dpb packages directory because sometimes I use make in ports and sometimes I use dpb, this allow recompiling packages in both areas. I do the same for distfiles.

4. Going further §

dpb can spread the compilation load over remote hosts (or even manage compilation for a different architecture), it's not complicated to setup but it's out of scope for the current guide. This requires setting up ssh keys and NFS shares, the difficulty is to think with the correct paths depending on chroot/not chroot and local / nfs.

I extremely recommend reading dpb man pages, it supports many options such as providing it a list of pkgpaths (package address such as editor/vim or www/nginx) or building ports in random order.

Here is a simply command to generate a list of pkgpaths of outdated packages on your system compared to the ports tree, the -q parameter is to make it a lot quicker but less accurate for shared libraries.

/usr/ports/infrastructure/bin/pkg_outdated -q | awk '/\// { print $1 }'

5. Conclusion §

I use dpb when I want to update my packages from sources because the binary packages are not yet available or if I want to build a new package in a clean environment to check for missing dependencies, however I use a simple "make" when I work on a port.

Extend Guix Linux with the nonguix repository

Written by Solène, on 27 May 2021.
Tags: #guix

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1. Introduction §

Guix is a full open source Linux distribution approved by the FSF, meaning it's fully free. However, for many people this will mean the drivers requiring firmwares won't work and their usual software won't be present (like Firefox isn't considered free because of trademark issue).

A group of people is keeping a parallel repository for Guix to add some not-100% free stuff like kernel with firmware loading capability or packages such as Firefox, this can be added to any Guix installation quite easily.

nonguix git repository

Guix project website

2. Configuration §

Most of the code and instructions you will find here come from the nonguix README, you need to add the new channel to download the packages or the definitions to build them if they are not available as binary packages (called substitutions) yet.

Create a new file /etc/guix/channels.scm with this content:

(cons* (channel
        (name 'nonguix)
        (url "https://gitlab.com/nonguix/nonguix")
        ;; Enable signature verification:
        (introduction
         (make-channel-introduction
          "897c1a470da759236cc11798f4e0a5f7d4d59fbc"
          (openpgp-fingerprint
           "2A39 3FFF 68F4 EF7A 3D29  12AF 6F51 20A0 22FB B2D5"))))
       %default-channels)

And then run "guix pull" to get the new repository, you have to restart "guix-daemon" using the command "herd restart guix-daemon" to make it accounted.

3. Deploy a new kernel §

If you use this repository you certainly want to have the kernel provided that allow loading firmwares and the firmwares, so edit your /etc/config.scm

(use-modules (nongnu packages linux)
             (nongnu system linux-initrd))

(operating-system ;; you should already have this line
  (kernel linux)
  (initrd microcode-initrd)
  (firmware (list linux-firmware))
  #...

Then you use "guix system reconfigure /etc/config.scm" to rebuild the system with the new kernel, you will certainly have to rebuild the kernel but it's not that long. Once it's done, reboot and enjoy.

4. Installing packages §

You should also have packages available now. You can enable the channel for your user only by modifying ~/.config/guix/channels.scm instead of the system wide /etc/channels.scm file. Note that you may have to build the packages you want because the repository doesn't build all the derivations but only a few packages (like firefox, keepassxc and a few others).

Note that Guix provide flatpak in its official repository, this is a workaround for many packages like "desktop app" for instant messaging or even Firefox, but it doesn't integrates well with the system.

5. Gaming §

There is also a dedicated gaming channel!

Guix gaming channel

6. Conclusion §

The nonguix repository is a nice illustration that it's possible to contribute to a project without forking it entirely when you don't fully agree with the ideas of the project. It integrates well with Guix while being totally separated from it, as a side project.

If you have any issues related to this repository, you should seek help from the nonguix project and not Guix because they are not affiliated.

How to use WireGuard VPN on Guix

Written by Solène, on 22 May 2021.
Tags: #guix #vpn

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1. Introduction §

Today I had to setup a Wireguard tunnel on my Guix computer (my email server is only reachable from Wireguard) and I struggled a bit to understand from the official documentation how to put the pieces together.

In Guix (the operating system, and not the foreign Guix on an existing distribution) you certainly have a /etc/config.scm file that defines your system. You will have to add the Wireguard configuration in it after generating a private/public keys for your Wireguard.

Guix project website

Guix Wireguard VPN documentation

2. Key generation §

In order to generate Wireguard keys, install the package Wireguard with "guix install wireguard".

# umask 077 # this is so to make files only readable by root
# install -d -o root -g root -m 700 /etc/wireguard
# wg genkey > /etc/wireguard/private.key
# wg pubkey < /etc/wireguard/private.key > /etc/wireguard/public

3. Configuration §

Edit your /etc/config.scm file, in your "(services)" definition, you will define your VPN service. In this example, my Wireguard server is hosted at 192.168.10.120 on port 4433, my system has the IP address 192.168.5.1, I also defines my public key but my private key is automatically picked up from /etc/wireguard/private.key

(services (append (list
      (service wireguard-service-type
             (wireguard-configuration
              (addresses '("192.168.5.1/24"))
              (peers
               (list
                (wireguard-peer
                 (name "myserver")
                 (endpoint "192.168.10.120:4433")
                 (public-key "z+SCmAMgNNvkeaD0nfBu4fCrhk8FaNCa1/HnnbD21wE=")
                 (allowed-ips '("192.168.5.0/24"))))))))
      %desktop-services))

If you have the default "(services %desktop-services)" you need to use "(append " to merge %desktop-services and new services all defined in a "(list ... )" definition.

The "allowed-ips" field is important, Guix will automatically make routes to these networks through the Wireguard interface, if you want to route everything then use "0.0.0.0/0" (you will require a NAT on the other side) and Guix will make the required work to pass all your traffic through the VPN.

At the top of the config.scm file, you must add "vpn" in the services modules, like this:

# I added vpn to the list
(use-service-modules vpn desktop networking ssh xorg)

Once you made the changes, you can use "guix system reconfigure" to make the changes, if you do multiples reconfigure it seems Wireguard doesn't reload correctly, you may have to use "herd restart wireguard-wg0" to properly get the new settings (seems a bug?).

4. Conclusion §

As usual, setting Wireguard is easy but the functional way make it a bit different. It took me some time to figure out where I had to define the Wireguard service in the configuration file.

Backup software: borg vs restic

Written by Solène, on 21 May 2021.
Tags: #backup #openbsd #unix

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1. Introduction §

Backups are important, lot of our life is now related to digital data and it's important to take care of them because computers are unreliable, can be stolen and mistakes happen. I really like two programs which are restic and borg, they have nearly the same features but it's hard to decide between both, this is an attempt to understand the differences for my use case.

2. Restic §

Restic is a backup software written in Go with a "push" workflow, it supports data deduplication within a repository and multiple systems using the same repository and also encryption.

Restic can backup to a remote sftp server but also many network services storage like S3/Minio and even more when using with the program rclone (which can turn any supported backend into a compatible restic backend). Restic seems compatible with Windows (I didn't try).

restic website

3. Borg §

Borg is a backup software written in Python with a "push" workflow, it supports encryption, data deduplication within a repository and compression. You can backup to a remote server using ssh but the remote server requires borg to be installed.

It's a very good and reliable backup software. It has a companion app named "borgmatic" to automate the backup process and snapshots managements (daily/hourly/monthly ... and integrity checking).

*BSD specific note: borg can honor the "nodump" flag in the filesystem to skip saving those files.

borgbackup website

borgmatic website

4. Experiment §

I've been making a backup of my /home/ partition (minus some directories that has been excluded in both cases) using borg and restic. I always performed the restic backup and then the borg backup, measuring bandwidth for each and execution time for each.

There are five steps: init for the first backup of lot of data, little changes twice, which is basically opening firefox, browsing a few pages, closing it, refreshing my emails in claws-mail (this changes a lot of small files) and use the computer for an hour. There is a massive change as fourth step, I found a few game installers that I unzipped, producing lot of small files instead of one big file and finally, 24h of normal use between the fourth and last step which is a good representation of a daily backup.

4.1. Data §

				restic	borg
Data transmitted (MB)
---------------------
Backup 1 (init)			62860	53730
Backup 2 (little changes)	15	26
Backup 3 (little changes)	168	171
Backup 4 (massive changes)	4820	3910
Backup 5 (typical day of use)	66	44
		
Local cache size (MB)
---------------------
Backup 1 (init)			161	45
Backup 2 (little changes)	163	45
Backup 3 (little changes)	207	46
Backup 4 (massive changes)	211	47
Backup 5 (typical day of use)	216	47
		
Backup time (seconds)
---------------------
Backup 1 (init)			2139	2999
Backup 2 (little changes)	38	131
Backup 3 (little changes)	43	114
Backup 4 (massive changes)	201	355
Backup 5 (typical day of use)	50	110

Repository size (GB)		65	56

4.2. Analysis §

Borg was a lot slower than restic but in my experiment the remote ssh server is a dual core atom system, borg is using a process on the other end to manage the data, so maybe that CPU was slowing the backup process. Nevertheless, in my real use case, borg is effectively slower.

Most of the time, borg was more bandwidth effective than restic: it saved 15% of bandwidth for the first backup and 18% after some big changes, but in some cases it used a bit more bandwidth. I have no explanation for this, I guess it depends how file chunks are calculated, if a big database file is changing then one may be able to save only the difference and not the whole file. Borg is also compressing the data (using lz4 by default), this may explain the bandwidth saving that doesn't work for binary data.

The local cache (typically in /root/.cache/) was a lot bigger for restic than for borg, and was increasing slightly at each new backup while borg cache never changed much.

Finally, the whole repo size holding all the snapshots has a different size for restic and borg, respectively 65 GB and 56 GB, which makes a 14% difference between each which may due to the compression done by borg.

5. Other backup software §

I tested Restic and Borg because they are both good software using the "push" workflow (local computer sends the data) making full snapshots of every backup, but there are many other backup solution available.

- duplicity: fully scriptable, works over many remote protocols but requires a full snapshot and then incremental snapshots to work, when you need to make a new full snapshot it will take a lot of space which is not always convenient. Supports GPG encrypted backup stored over FTP, this is useful for some dedicated server offering 100GB of free FTP.

- burp: not very well known, the setup uses TLS certificates for encryption, requires a burp server and a burp client

- rsnapshot: based on rsync, automate the rotation of backups, use hard links to avoid data duplication for files that didn't change between two backups, it pulls data from servers from a central backup system.

- backuppc: a perl app that will pull data from servers to its repository, not really easy to use

- bacula: enterprise grade solution that I never got to work because it's really complicated but can support many things, even saving on tapes

6. Conclusion §

In this benchmark, borg is clearly slower but was the most storage and bandwidth efficient. On the other hand, restic is easier to deploy (static binary) and supports a simple sftp server while borg requires borg installed on both sides.

A biggest difference between restic and borg, is that restic supports multiples systems backup in the same repository, allowing a massive data deduplication gain across machines, while a borg repository is for single system (it could work with multiples systems but they should not backup at the same time and they would have to rebuild the local cache every time which is slow).

I'll stick with borg because the backup time isn't a real issue given it's not dramatically slower than restic and that I really enjoy using borgmatic to automatically manage the backups.

For doing backups to a remote server over the Internet, the bandwidth efficiency would be my main concern of all the differences, borg seems a clear winner here.

How to setup wireguard on NixOS

Written by Solène, on 18 May 2021.
Tags: #nixos #networking

Comments on Fediverse/Mastodon

1. Introduction §

Today I will share my simple wireguard setup using NixOS as a wireguard server. The official documentation is actually very good but it didn't really fit for my use case. I have a server with multiples services but some of them need to be only reachable through wireguard, but I don't want to open all ports to wireguard either.

As a quick introduction to Wireguard, it's an UDP based VPN protocol with the specificity that it's stateless, meaning it doesn't huge any bandwidth when not in use and doesn't rely on your IP either. If you switch from an IP to another to connect to the other wireguard peer, it will be seamless in regards to wireguard.

NixOS wireguard documentation

2. Wireguard setup §

The setup is actually easy if you use the program "wireguard" to generate the keys. You can use "nix-shell -p wireguard" to run the following commands:

umask 077 # this is so to make files only readable by root
wg genkey > /root/wg-private
wg pubkey < /root/wg-private > /root/wg-public

Congratulations, you generated a wireguard private key in /root/wg-private and a wireguard public key in /root/wg-public, as usual, you can share the public key with other peers but the private key must be kept secret on this machine.

Now, edit your /etc/nixos/configuration.nix file, we will create a network 192.168.100.0/24 in which the wireguard server will be 192.168.100.1 and a laptop peer will be 192.168.100.2, the wireguard UDP port chosen is 5553.

networking.wireguard.interfaces = {
      wg0 = {
              ips = [ "192.168.100.1/24" ];
              listenPort = 5553;
              privateKeyFile = "/root/wg-private";
              peers = [
              { # laptop
               publicKey = "uPfe4VBmYjnKaaqdDT1A2PMFldUQUreqGz6v2VWjwXA=";
               allowedIPs = [ "192.168.100.2/32" ];
              }];
      };
};

3. Firewall configuration §

Now, you will also want to enable your firewall and make the UDP port 5553 opened on your ethernet device (eth0 here). On the wireguard tunnel, we will only allow TCP port 993.

networking.firewall.enable = true;

networking.firewall.interfaces.eth0.allowedTCPPorts = [ 22 25 465 587 ];
networking.firewall.interfaces.eth0.allowedUDPPorts = [ 5553 ];

networking.firewall.interfaces.wg0.allowedTCPPorts = [ 993 ];

Specifically defining the firewall rules for eth0 are not useful if you want to allow the same ports on wireguard (+ some other ports specifics to wg0) or if you want to set the wg0 interface entirely trusted (no firewall applied).

4. Building §

When you have done all the changes, run "nixos-rebuild switch" to apply the changes, you will see a new network interface wg0.

5. Conclusion §

I obviously stripped down my real world use case but if for some reasons you want a wireguard tunnel stricter than what's available on the public network interfaces rules, this is how you do.

How to switch to NixOS development version

Written by Solène, on 17 May 2021.
Tags: #nixos

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This short guide will explain you how to switch a NixOS installation to the unstable channel, understand the development version.

nix-channel --add https://channels.nixos.org/nixos-unstable nixos

You will have to reload the channel list using the command "nix-channel --update" and then you can upgrade your system using "nixos-rebuild switch".

If you have issues, you can rollback using "nix-channel --rollback" that will set the channels list to the last state before "--update".

Nix channels wiki page

Nix-channel man page

Turn your Xorg in black and white

Written by Solène, on 15 May 2021.
Tags: #unix

Comments on Fediverse/Mastodon

1. Introduction §

If for some reasons you want to turn you display in black and white mode and you can't control this on your display (typically a laptop display won't allow you to change this), there are solutions.

2. Compositor way §

The best way I found is to use a compositor, fortunately I'm already using "picom" as a compositor along with fvwm2 because I found the windows are getting drawn faster when I switch between desktop with the compositor on. You will want to run the compositor in your ~/.xsession file before running your window manager.

The idea is to run picom with a shader that will turn the color into a gray scale, restart picom with no parameter if you want to get colors back.

picom -b --backend glx --glx-fshader-win  "uniform sampler2D tex; uniform float opacity; void main() { vec4 c = texture2D(tex, gl_TexCoord[0].xy); float y = dot(c.rgb, vec3(0.2126, 0.7152, 0.0722)); gl_FragColor = opacity*vec4(y, y, y, c.a); }"

It was surprisingly complicated to find how to do that. I stumbled on "toggle-monitor-grayscale" project on github which is a long script to automate this depending on your graphic card, I only took the part I needed for picom.

toggle-monitor-grayscale project on Github

3. Conclusion §

I have no idea why someone would like to turn the screen in black and white, but I've been curious to see how it would look like and if it would be nicer for the eyes, it's an interesting experience I have to admit but I prefer to keep my colors.

Why do I write this blog?

Written by Solène, on 14 May 2021.
Tags: #blog

Comments on Fediverse/Mastodon

1. Why do I write this blog? §

I decided to have a blog when I started to gather personal notes when playing with FreeBSD, while I wanted my notes to be easy to read and understand I also chose to publish them online so I could read them even at work.

The earlier articles were more about how to do X Y, they were reminders for myself that I was sharing with the world, I never intended to have readers at that time. I enjoyed writing and sharing, I had a few friends who were happy to subscribe to the RSS feed and they were proof-reading after my publications.

Over time, I wanted to make it a place to speak about unusual topic like StumpWM, Common LISP, Guix and weird Unix tricks. It made me very happy because I got feedback from more people over time so I kept doing this.

At some point, I got a lot more involved in the OpenBSD community and I think most of my audience is related to OpenBSD now. I want to share what you can do with OpenBSD, how it would be different than with another system, steps-by-steps guides. I hope it helped some people to jump to OpenBSD and they enjoy it as well now. At the same time, I try to be as honest as possible when I publish about something, this blog is making absolutely no money, there are no ads, I would have absolutely nothing to gain not being honest in my articles. I value precision and accuracy, I try to link to official documentation most of the time instead of doing a copy/paste that will become obsolete over time.

Speaking of obsolescence, I usually re-read all my texts (and it takes a long time) once a year, to check if everything seems still correct. I could see packages that not longer exist, configuration syntax that may have changed or just a software version that is really old, this takes a lot of time because I value all my publications and not only the most recent one.

I write because I have fun writing and I'm happy to make my readers happy. I often get some emails from people I don't know giving me their thoughts about an article, I'm always surprised but very happy when this happen and I always reply to those persons.

I have no schedule when I write, sometimes I plan texts but I can't get them right so I delete them. Sometimes months can pass between two publications, I do not really care, I'm not targeting any publication rate, that would be against the fun.

2. Why not you? §

This may sound odd, but I wanted to write this text mainly to encourage other people to write and publish their own blog. Why not you? On the technical side, there are many free hosting available in the opensource community and you have plenty of awesome static website generators available nowadays.

If you want to start the adventure, just write and publish. Propose a way to contact you, I think it's important for readers to be able to reach you, they are very nice (at least I never had any issue): they could report mistakes or give you links to things you may enjoy on the same topic as your publication.

Don't think of money, styling, hit rate, visit numbers, it doesn't matter. The true gems on the Internet are those old fashions websites of early 2000 with many ugly jpg, wrong colors but with insane content about unusual and highly specific topics. I have in mind the example of a website about a French movie, the author had found every spot in France where the movie has been filmed, he has contacted every cast in the movie even the most insignificant ones to ask about stories and gathered many pictures and stories about the making of the film. None of this would ever happen in a web driven by money and ranking and visitors.

Simple solution VS over-engineering

Written by Solène, on 13 May 2021.
Tags: #software #opensource

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to share my thoughts about software in general. I've been using and writing software for a long time and I've seen some patterns over time.

2. Simple solutions §

I am a true adept of the "KISS" philosophy, in which KISS stands for Keep It Simple Stupid, meaning make your software easy to understand and not try to make it smart. It works most of the time but after you reach your goal with your software, you may be tempted to add features over it, or make it faster, or make it smarter, it usually doesn't work.

3. Over-engineering §

In the opensource world, we have many bricks of software that we can put together to build better tools, but at some point, you may use too many of them and the service is unbearable in regards to maintenance / operating, the current trend is to automate this by providing those huge stacks of software through docker. It may be good enough for users, it does certainly the job and it works, why should we worry?

4. Failure and reversibility §

When you use a complicated software, ALWAYS make sure you have a way out: either replace product A with product B or make sure the code is easy to fix. If you plan to invest yourself into deploying a complex program that will store data (like Nextcloud or Paperless-ng), the first question you should have is: how can I move away from it?

Why would you move away from something you are deploying right now because it's good? Software can be unmaintained after some time and you certainly don't want to run a network based obsolete program, due to dependency hell it may not work in the future because it relies on some component that is not available anymore (think python2 here), you may have bugs after a long use that nobody want to fix and prevent you to use the software correctly (scalability issue due to data growth).

There are tons of reasons that something can fail, so it's always important to think about replacements.

- are the data stored in a way you can extract? data could be saved as a plain file on the file system but could also be stored in some complicated repositories format (ipfs)

- if data are encrypted, can you decrypt it? If it's GPG based, you can always work with it, but if it's custom made chunk encryption like Seafile does, it's a lot harder without the real program.

- if the software is packaged for your system, it may not be forever, you may have to package it yourself in a few years if you want to keep it up to date

- if you rely on external API, it may be not able indefinitely. Web browser extensions are a good example, those programs have tightened what extensions could do over time and many tricks had to be used to migrate from API to API. When you rely on a extension, it's a real issue when the extension can't work anymore.

5. Build your own replacement? §

There are many situations in which you may prefer to build your own service with your own code than using a software ready on the shelf. There are always pros and cons, you gain control and reliability over features and ease of use. Not everyone is able to write such scripts and you may fail and have to deal with the consequences when you do so, this is something that must be kept in mind.

- backups: you could use rsync instead of a complex backup system

- "cloud" file storage: rsync/sftp are still a viable option to upload a file "to the cloud" if you have a server, a simple https server would be enough to share the file, the checksum of the file could be used as an unique and very long file name.

- automation: a shell script executed over ssh could replace ansible or salt-stack to some extent

There are many use case in which the administrator may prefer a home-made solution, but in a company context, you may have to rely on that very person instead of relying on a complex software, which moves the problem to another level.

6. Conclusion §

There are many reasons a software could fail, be abandoned, not work anymore, you should always assess such situations if you don't want to build a fragile service. Easiest ideas have less features but are a lot more reliable and resistant to time than complex implementations. The more code you involve, the more issues you will have.

We are free to use what we want, in open source we are even free to make changes to the code we use, this is fantastic. Choice always come with pros and cons and it's always better to think before hand than facing unwise consequences.

Introduction to git-annex (Port Of The Week)

Written by Solène, on 12 May 2021.
Tags: #git #versioning #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Now that git-annex is available as a package on OpenBSD I can use it again. I've been relying on it a few years ago but it was really complicated for me to compile it and I gave up. Since I really missed it, I'm now back to it and I think it's time to share about this wonderful piece of software.

git-annex is meant to help you manage your data like you would manage books in a library, you have a database telling you where the books are and you can find them on the shelves, or at least you can know who borrowed the book. We are working with digital files that can be copied here so the analogy doesn't fully work, but you could want to put your data in an external hard drive but not everything, and you may want to have some data on multiples devices for safety reasons, git-annex automates this.

It works very well for files that are not changing much, I call them "static files", they are music, videos, pictures, documents. You don't really want to use git-annex with files you edit everyday, it doesn't work well because the process can be a bit tedious.

git-annex may not be easy to understand at first, I suggest you try locally to grasp its purpose.

git-annex official website

what git-annex is not

2. Cheat sheet §

Let's create a cheat sheet first. Most git-annex commands have a dedicated man page, but can also provide a simpler help by using "git annex help somecommand".

2.1. Create the repository §

The first step is to create a repository which is based on git, then we will tell git-annex to init it too.

mkdir ~/MyDataLibrary && cd ~/MyDataLibrary
git init
git annex init "my-computer"

2.2. Add a file §

When you want to register a file in git annex, you need to use "git annex add" to add it and then "git commit" to make it permanent. The files are not stored in the git repository, it will only contains metadata.

git annex add Something
git commit -m "I added something"

Example:

$ echo "hello there" > hello
$ ls -l hello
-rw-r--r--  1 solene  wheel  12 May 12 18:38 hello
$ git annex add hello
add hello
ok
(recording state in git...)
$ ls -l hello
lrwxr-xr-x  1 solene  wheel  180 May 12 18:38 hello -> .git/annex/objects/qj/g5/SHA256E-s12--aadc1955c030f723e9d89ed9d486b4eef5b0d1c6945be0dd6b7b340d42928ec9/SHA256E-s12--aadc1955c030f723e9d89ed9d486b4eef5b0d1c6945be0dd6b7b340d42928ec9
$  git status hello
On branch master
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
        new file:   hello

2.3. Make changes to a file §

If you want to make changes to a file, you first need to "unlock" it in git-annex, which mean the symbolic link is replaced by the file itself and is no longer in read-only. Then, after your changes, you need to add it again to git-annex and commit your changes.

git annex unlock file
vi file
git annex add file
git commit -m "I changed something" file

2.4. Add a remote encrypted repository §

If you want to store data (for duplication) on a remote server using ssh you can use a remote of type "rsync" and encrypt the data in many fashions (GPG with hybrid is the best). This will allow to store data on remote untrusted devices.

git annex initremote my-remote-server type=rsync rsyncurl=remote-server.com:/home/solene/git-annex-data keyid=my-gpg@address encryption=hybrid

After this command, I can send files to my-remote-server.

git-annex website about encryption

git-annex website about special remotes

2.5. Manage data from multiple computers (with ssh) §

**This is a way to have a central git repository for many computers, this is not the best way to store data on remote servers**.

If you want to use a remote server through ssh, there are two ways: mounting the remote file system using sshfs or use a plain ssh. If you use sshfs, then it falls as a standard local file system like an external usb drive, but if you go through ssh, it's different.

You need to have a key authentication based for the remote ssh and you also need git-annex on the remote server. It's important to have a bare git repo.

cd /home/data/
git init --bare
git annex init "remote-server"

On your computer:

git remote add remote-server ssh://hostname:/home/data/
git fetch remote-server

You will be able to use commands related to repositories now!

2.6. List files and where they are stored §

You can use the "git annex list" command to list where your files are physically stored.

In the following example you can see which files are on my computer and which are available on my remote server called "network", "web" and "bittorrent" are special remotes.

here
|network
||web
|||bittorrent
||||
X___ Documentation/Nim/Dominik Picheta - Nim in Action-Manning Publications (2017).pdf
X___ Documentation/ada/Ada-Distilled-24-January-2011-Ada-2005-Version.pdf
X___ Documentation/ada/courseada1.pdf
X___ Documentation/ada/courseada2.pdf
X___ Documentation/ada/courseada3.pdf
X___ Documentation/scheme/artanis.pdf
X___ Documentation/scheme/guix.pdf
X___ Documentation/scheme/manual_guix.pdf
X___ Documentation/skribilo/skribilo.pdf
X___ Documentation/uck2ep1.pdf
X___ Documentation/uck2ep2.pdf
X___ Documentation/usingckermit3e.pdf
XX__ Musique/Daft Punk/01 - Albums/1997 - Homework/01 - Daftendirekt.flac
XX__ Musique/Daft Punk/01 - Albums/1997 - Homework/02 - Wdpk 83.7 fm.flac
XX__ Musique/Daft Punk/01 - Albums/1997 - Homework/03 - Revolution 909.flac
XX__ Musique/Daft Punk/01 - Albums/1997 - Homework/04 - Da Funk.flac
XX__ Musique/Daft Punk/01 - Albums/1997 - Homework/05 - Phoenix.flac
_X__ Musique/Alan Walker/Alan Walker - Different World/01 - Alan Walker - Intro.flac
_X__ Musique/Alan Walker/Alan Walker - Different World/02 - Alan Walker, Sorana - Lost Control.flac
_X__ Musique/Alan Walker/Alan Walker - Different World/03 - Alan Walker, Julie Bergan - I Don_t Wanna Go.flac

2.7. List files locally available §

If you want to list the files for which you have the content available locally, you can use the "list" command from git-annex but only restrict to the group "here" representing your local repository.

git annex list --in here

3. Work with a remote repository §

3.1. Delete a repository §

Simply mark it as "dead".

git annex dead $repo_name

3.2. Adding a remote repository GPG encrypted §

git annex initremote $name type=rsync rsyncurl=remote-server:/home/solene/mydirectory keyid=your@email encryption=shared

3.3. Copy files to a remote §

If you want to duplicate files between repositories to have multiples copies you can use "git annex copy".

git annex copy Music -t remote-server

3.4. Move files to a remote §

If you want to move files from a repository to another (removing the content from origin) you can use "git annex move" which will copy to destination and remove from origin.

git annex move Music -t remote-server

3.5. Get a file content §

If you don't have a file locally, you can fetch it from a remote to get the content.

git annex get Music/Queen

3.6. Forget a file locally §

If you don't want to have the file locally because you don't have disk space or you simply don't want it, you can use the "drop" command. Note that "drop" is safe because git-annex won't allow you to drop files that have only one copy (except if you use --force of course).

git annex drop Music/Queen

Real life example: I have a very huge music library but my laptop SSD is too small, I get get some music I want and drop the files I don't want to listen for a while.

3.7. Use mincopies to enforce multi repository data duplication §

The numcopies and mincopies variables can be used to tell git-annex you want exactly or at least "n" copies of the files, so it will be able to protect you from accidental deletions and also help uploading files to other repositories to match the requirements.

3.7.1. Enable per directory recursively §

echo "* annex.mincopies=2" > .gitattributes

3.7.2. Only upload files not matching the num copies §

If you have multiples repositories and some files doesn't match the copies requirements, you can use the following commands to only push the files missing copies.

git annex copy --auto -t remote-server

Real life example: I want my salaries PDF to be really safe, I can ask to have 2 copies of those and then run a sync to the remote server which will proceed to upload them if there is only one copy of the file yet.

3.8. Verifying integrity and requirements §

There is the git-annex fsck command which will check the integrity of every file in the local repository and reports you if they are sane (or not), but it will also tell you which file doesn't meet the mincopies requirements.

git annex fsck

4. Reversibility §

If for some reasons you want to give up git-annex, you can easily get all your files back like a normal file system by using "git annex unlock ." on the top directory of your repository, every local files will be replaced by their physical copy instead of the symlink. Reversibility is very important when you deal with your data because it means you are not stuck forever with a tool in case it's broken or if you want to switch to another process.

5. My workflow §

I have a ~/DATA/ directory in which I have sub directories {documents,documentation,pictures,videos,music,images}, documents are papers or legal papers, documentation are mostly PDF. Pictures are family pictures and images are wallpapers or stupid images I want to keep.

I've set a mincopies to 2 for documents and pictures and my music is not on my computer but on a remote, I get the music files I want to listen when I'm on the local network with the computer having the files, I drop them locally when I'm bored.

6. Conclusion §

git-annex separates content from indexation, it can be used in many ways but it implies an archivist philosophy: redundancy, safety, immutability (sort of). It is not meant for backup, you can backup your directory managed by git-annex, it will save the data you have locally, you will have to make backup of your other data as well.

I love that tool, it's a very nice piece of software. It's unique, I didn't find any other program to achieve this.

6.1. More resources §

git-annex official walkthrough

git-annex special remotes (S3, webdav, bittorrent etc..)

git-annex encryption

Introduction to security good practices

Written by Solène, on 09 May 2021.
Tags: #security

Comments on Fediverse/Mastodon

1. Introduction §

I wanted to share my thoughts about security in regards to computers. Let's try to summarize it as a list of rules.

If you read it and you disagree, please let me know, I can be wrong.

2. Good practices §

Here is a list of good practices I've found over time.

2.1. Passwords policy §

Passwords are a mess, we need many of them every day but they are not practical. I do highly recommend to use an unique random password for every password needed. I switched to "keepassxc" to manage my passwords, there are many password managers on the market.

When I need to register a password, I use the longest possible allowed and I keep in my password database.

If I got hacked with my password database, all my passwords are leaked, but if I didn't use it and had only one password, good chance it would be registered somewhere and then the hacker would have access to everything too. The best situation would be to have a really effective memory but I don't want to rely on it.

I still recommend to have a few passwords in your memory, like the one for your backups, your user session and the one to unlock the password database.

When possible, use multi factor authentication. I like the TOTP (Timed One Time Password) method because it works without any third party service and can be stored securely in a backup.

2.2. Devices trust §

It's important to define a level of trust in the devices you use. I do not trust my Windows gaming computer, I would not let it have access to my password database. I do not trust my phone device enough for that job too.

If my phone requires a password, I generate one and keep it in my password database and I will create a QR code to scan with the phone instead of copying that very long password. The phone will have the password locally but not the entire database but yet it remains quite usable.

2.3. Define your threat model §

When you think about security, you need to think what kind of security you want, sometimes this will also imply thinking about privacy.

Let's think about my home file server, it's a small device which only one disk and doesn't have access to the internet. It could be hacked from a remote person, this is possible but very unlikely. On the other hand, a thief could come into my house a steal a few things, like this server and its data. It makes a lot of sense to use disk encryption for devices that could be stolen (let make it short, I mean all devices).

On the other hand, if I had to manage a mail server with IMAP / SMTP services on it, I would harden it a lot from external attacks and I would have to make some extra security policies for it.

2.4. Think about usability §

Most of the time, security and usability doesn't play together, if you increase security that will be at the expense of usability and vice-versa. I'll go back to my IMAP server, I could enable and enforce connecting over TLS for my users, that would prevent their connections to be eavesdropped. I could also enforce a VPN (that I manage myself, not a commercial VPN that can see all my traffic..) to connect to the IMAP server, that would prevent anyone without a VPN to connect to the server. I could also restrict that VPN connection from a list of public IP. I could require the VPN access from an allowed IP to be unlocked by an SSH connection requiring TOTP + password + public key to succeed.

At this point, I'm pretty sure my users will give up and put an automatic redirection of their emails to an other mail server which will be usable to them, I'd be defeated by my users because of too much security.

2.5. Don't lock yourself out §

When you come to encrypt everything or lock everything on the network, it could be complicated to avoid data loss or being locked out from the service.

If you have important passwords, you could use Shamir's Secret Sharing (I wrote about it a while back) to split a password in multiples pieces that you would convert as QR code and give a copy to a few person you know, to help you recover the data if you forget about the password once.

2.6. Backups §

It's important to make backups, but it's even more important to encrypt them and have them out in a different area of your storage. My practice here is to daily backup all my computer data (which is quite huge) but also backup only my most important data to remote servers. I can afford losing my music files but I'd prefer to be able to recover my GPG and SSH keys in case of huge disaster at home.

2.7. User management §

If a hacker got control of your user, it may be over for you. It's important to only run programs you trust and no network related services.

If you need to run something you are unsure, use a virtual machine or at least a dedicated user that won't have access to your user's data. My $HOMEDIR has a chmod 700 so only root and me can access it. If I need to run a service, I will use a dedicated user to it. It's not always convenient but it's effective.

3. Conclusion §

Good software with a good design are important for the security, but they don't do all the job when it comes to security. Users must be aware of risks and act accordingly.

How to run a NixOS VM as an OpenBSD guest

Written by Solène, on 08 May 2021.
Tags: #openbsd #nixos

Comments on Fediverse/Mastodon

1. Introduction §

This guide is to help people installing the NixOS Linux distribution as a virtual machine guest hosted on OpenBSD VMM hypervisor.

2. Preparation §

Some operations are required on the host but specifics instructions will be needed on the guest as well.

2.1. Create the disk §

We will create a qcow2 disk, this format allows not using all the reserved space upon creation, size will grow as the virtual disk will be filled with data.

vmctl create -s 20G nixos.qcow2

2.2. Configure vmd §

We have to configure the hypervisor to run the VM. I've chose to define a new MAC address for the VM interface to avoid collision with the host MAC.

vm "nixos" {
       memory 2G
       disk "/home/virt/nixos.qcow2"
       cdrom "/home/virt/latest-nixos-minimal-x86_64-linux.iso"
       interface { lladdr "aa:bb:cc:dd:ee:ff"  switch "uplink" }
       owner solene
       disable
}

switch "uplink" {
	interface bridge0
}

vm.conf man page

2.3. Configure network §

We need to create a bridge in which I will add my computer network interface "em0" to it. Virtual machines will be attached to this bridge and will be seen from the network.

echo "add em0" > /etc/hostname.bridge0
sh /etc/netstart bridge0

2.4. Start vmd §

We want to enable and then start vmd to use the virtual machine.

rcctl enable vmd
rcctl start vmd

2.5. NixOS and serial console §

When you are ready to start the VM, type "vmctl start -c nixos", you will get automatically attached to the serial console, be sure to read the whole chapter because you will have a time frame of approximately 10 seconds before it boots automatically (if you don't type anything).

If you see the grub display with letters displayed more than once, this is perfectly fine. We have to tell the kernel to enable the console output and the desired speed.

On the first grub choice, press "tab" and append this text to the command line: "console=ttyS0,115200" (without the quotes). Press Enter to validate and boot, you should see the boot sequence.

For me it took a long time on starting sshd, keep waiting, that will continue after less than a few minutes.

2.6. Installation §

There is an excellent installation guide for NixOS in their official documentation.

Official installation guide

I had issues with DHCP so I've set the network manually, my network is in 192.168.1.0/24 and my router 192.168.1.254 is offering DNS too.

systemctl stop NetworkManager
ifconfig enp0s2 192.168.1.151/24 up
route add -net default gw 192.168.1.254
echo "nameserver 192.168.1.254" >> /etc/resolv.conf

The installation process can be summarized with theses instructions:

sudo -i
parted /dev/vda -- mklabel msdos
parted /dev/vda -- mkpart primary 1MiB -1GiB # use every space for root except 1 GB for swap
parted /dev/vda -- mkpart primary linux-swap -1GiB 100%
mkfs.xfs -L nixos /dev/vda1
mkswap -L swap /dev/vda2
mount /dev/disk/by-label/nixos /mnt
swapon /dev/vda2
nixos-generate-config --root /mnt
nano /mnt/etc/nixos/configuration.nix
nixos-install
shutdown now

Here is my configuration.nix file on my VM guest, it's the most basic I could want and I stripped all the comments from the base example generated before install.

{ config, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  boot.loader.grub.extraConfig = ''
    serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
    terminal_input --append serial
    terminal_output --append serial
  '';

  networking.hostName = "my-little-vm";
  networking.useDHCP = false;

  # COMMENT THIS LINE IF YOU DON'T WANT DHCP
  # networking.interfaces.enp0s2.useDHCP = true;


  # BEGIN ADDITION
  # all of these variables were added or uncommented
  boot.loader.grub.device = "/dev/vda";

  # required for serial console to work!
  boot.kernelParams = [
    "console=ttyS0,115200n8"
  ];

  systemd.services."serial-getty@ttyS0" = {
    enable = true;
    wantedBy = [ "getty.target" ]; # to start at boot
    serviceConfig.Restart = "always"; # restart when session is closed
  };

  # use what you want
  time.timeZone = "Europe/Paris";

  # BEGIN NETWORK
  # define network here
  networking.interfaces.enp0s2.ipv4.addresses = [ {
        address = "192.168.1.151";
        prefixLength = 24;
  } ];
  networking.defaultGateway = "192.168.1.254";
  networking.nameservers = [ "192.168.1.254" ];
  # END NETWORK

  # enable SSH and allow X11 Forwarding to work
  services.openssh.enable = true;
  services.openssh.forwardX11 = true;

  # Declare a user that can use sudo
  users.users.solene = {
    isNormalUser = true;
    extraGroups = [ "wheel" ];
  };

  # declare the list of packages you want installed globally
  environment.systemPackages = with pkgs; [
     wget vim
  ];

  # firewall configuration, only allow inbound TCP 22
  networking.firewall.allowedTCPPorts = [ 22 ];
  networking.firewall.enable = true;
  # END ADDITION

  # DONT TOUCH THIS EVER EVEN WHEN UPGRADING
  system.stateVersion = "20.09"; # Did you read the comment?

}

Edit /etc/vm.conf to comment the cdrom line and reload vmd service. If you want the virtual machine to automatically start with vmd, you can remove the "disable" keyword.

Once your virtual machine is started again with "vmctl start nixos", you should be able to connect to ssh to it. If you forgot to add users, you will have to access the VM console with "vmctl console", log as root, modify the configuration file, type "nixos-rebuild switch" to apply changes, and then "passwd user" to define the user password. You can set a public key when declaring a user if you prefer (I recommend).

3. Install packages §

There are three ways to install packages on NixOS: globally, per-user or for a single run.

- globally: edit /etc/nixos/configuration.nix and add your packages names to the variable "environment.systemPackages" and then rebuild the system

- per-user: type "nix-env -i nixos.firefox" to install Firefox for that user

- for single run: type "nix-shell -p firefox" to create a shell with Firefox available in it

Note that the single run doesn't mean the package will disappear, it's most likely... not "hooked" into your PATH so you can't use it. This is mostly useful when you make development and you need specific libraries to build a project and you don't always want them available for your user.

4. Conclusion §

While I never used a Linux system as a guest in OpenBSD it may be useful to run Linux specific software occasionally. With X forwarding, you can run Linux GUI programs that you couldn't run on OpenBSD, even if it's not really smooth it may be enough for some situations.

I chose NixOS because it's a Linux distribution I like and it's quite easy to use in the regards it has only one configuration file to manage the whole system.

How to install Gnome on OpenBSD

Written by Solène, on 07 May 2021.
Tags: #openbsd #unix #gnome

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1. Introduction §

This article will explain how to install the Gnome desktop on OpenBSD. You need access to the root user to proceed.

2. Instructions §

As root, run "pkg_add gnome gnome-extras" which will install the meta-package gnome listing all the required dependencies to have a full working Gnome installation and the -extras package containing all gnome related programs.

You should see this output after "pkg_add" has finished installing the packages, it's important to read the "pkg-readme" files which are specific instructions to packages.

New and changed readme(s):
        /usr/local/share/doc/pkg-readmes/gnome
        /usr/local/share/doc/pkg-readmes/upower

The most important file is the pkg-readme about Gnome that contains clear instructions about the configuration required to run Gnome. That file has a "Too long didn't read" section at the end for people in a hurry which contain instructions to copy/paste.

3. Tweaks §

There is an "app" named Tweaks that allow further customization than Gnome3 is allowing, like virtual desktop being horizontal, add menus on the top panel or change various behavior of Gnome.

4. Conclusion §

While the Gnome installation is not fully automated, it requires only a few instructions to get it installed and fully operational.

Gnome3 after the first start wizard
Gnome3 after the first start wizard
Gnome3 desktop with a few customizations
Gnome3 desktop with a few customizations

Synchronization files software

Written by Solène, on 04 May 2021.
Tags: #unix

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1. Introduction §

In this article I will introduce you to various opensource file synchronization programs and their according workflows. I may not know them all, obviously.

I can't give a full explanation of each of them, but I will tell you enough so you can know if it could be of any interest to you.

2. Software §

There are many software out there, with pros and cons, to match our file synchronization requirements.

2.1. rsync §

rsync is the leader for simple file replication, it can take care that the destination will exactly match the source data. It's available mostly everywhere and using ssh as a transport it's also secure.

rsync is really the reference for a one-way synchronization.

rsync website

2.2. lsyncd §

lsyncd is meant to be used in an environment for near to realtime synchronization. It will check for changes in the monitored directories and will replicate the changes on a remote system (using rsync by default).

lsyncd website

2.3. unison §

unison is like rsync but can synchronize in both way, meaning you can keep two directories synchronized without having to think in which order you need to transfer. Obviously, in case of conflict you will have to resolve and pick which file you want to keep. This is a well established software that is very reliable.

unison website

2.4. rclone §

rclone is like rsync but will support many backend instead of relying on ssh to connect to a remote source. It's mostly used to transfer files from or to Cloud services by making a glue between core rclone and the service API.

I covered rclone in a previous article if you want more information.

rclone website

2.5. syncthing §

syncthing is a fantastic tool to keep directories synchronized between computers/phones. It's a service you run, you define what directories you want to export, and on other syncthing instances you can add those exports and it will be kept synchronized together without tuning. It uses a public tracker to find peers so you don't have to mess with NAT or redirections, and if you want full privacy you can use direct IPs. Data are encrypted during transfers.

It has the advantages of working in full automatic mode and can exchange in both ways in a same directory, with multiples instance on a same share, it can also keep previous copies of deleted / replaced files and support many other features.

syncthing website

2.6. sparkleshare §

SparkleShare isn't well known but still does the job very efficiently. It offers automatic synchronization of a directory with other peers based on a git directory, basically, if you add a file or make a change, it's committed and pushed to the remote repositories. If someone make a change, you will receive it too.

While it works very well, it's mostly suited for non binary data because of the git backend. You can't really delete old data so the sparkleshare share will grow over time.

SparkleShare website

2.7. nextcloud §

Nextcloud has a file synchronization capability, it's mostly used to upload your data to a remote server and be able to access it from remote, but also share a file or a directory in read only or read/write to other people. It's really a huge toolbox that requires a 24/7 server but provide many features for sharing files. A not so well known feature is the ability to share a directory between Nextcloud instances.

Nextcloud has its core in PHP for the www access but also phone or desktop applications.

Nextcloud can encrypt stored data.

Nextcloud website

2.8. seafile §

Seafile is a centralized server to store data, like netxtcloud. It's more focused on file storage than nextcloud, but will provide solid features and also companions apps for phones and desktop.

seafile website

2.9. git-annex §

I kept the best for the end. Git-annex is a special beast that would have deserved a full article for it but I never found how to approach it.

git-annex is a command line tool to manage a library of data and will delegate actual transfer to the according protocol.

WHAT DOES IT MEAN? Let's try an analogy.

You are in a house, you have many things in your house: movies, music, books, papers. If you want to keep track of where is stored something, you need an inventory, in which you will label where you stored this paper, this DVD, this book etc... This is what git-annex is doing.

git-annex will allow you to entirely manage data and spread it on different location (with redundancy possible) and let you access natively (or at least tell you where to get it). A real life example would be to use an external hard drive to store big files like music or movies but use a remote server to backup important documents. But you may want your documents to also be on the external hard drive, or even two hard drives, you can tell git-annex to manage that.

git-annex can give you the current state of your library without having the files locally, it will replace the whole hierarchy with symlinks to the real files if they are on your computer, meaning you can get the files when you need them or simply work on that index to remove files and then tell git-annex to proceed to deletion if possible (or when it can, like when you get internet access or you connect that external hard drive).

The draw back is that all the tracked files are symbolic links to a potentially non existing file and that you need a specific workflow of unlocking file in order to make changes, and then store it again.

I've been using it for years for data that doesn't change much (administrative documents, music, pictures) but it's certainly not suitable for tracking logs or often modified files.

The name contains "git" but git-annex only use gits to store the whole metadata, the data themselves are not in git.

git-annex website

3. Conclusion §

There are different strategies to synchronize files between computers, they can be one way, both way, allow other people to use them, manage at huge scale, realtime etc...

From my experience, we all manage our files in very different ways so I'm glad we have that many ways to synchronize them.

PS: don't forget to backup, it's not because you replicate your data that you don't need backup, sometimes it's easy to destroy all the data at once with a simple mistake.

OpenBSD: getting started

Written by Solène, on 03 May 2021.
Tags: #openbsd

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1. Introduction §

This is a guide to OpenBSD beginners, I hope this will turn to be an useful resource helping people to get acquainted to this operating system I love. I will use a lot of links because I prefer to refer to official documentation.

If you are new on OpenBSD, welcome aboard, this guide is for you. If you are not new, well, you may learn a few things.

2. Installation step §

This article is not about installing OpenBSD. There are enough official documentation for this.

OpenBSD FAQ about Installation

3. Booting the first time §

So, you installed OpenBSD, you chose to enable X (the graphical interface at boot) and now you face a terminal on a gray background. Things are getting interesting here.

3.1. Become super user (root) §

You will often have to use the root account for commands or modifying system files.

su -l

You will have to type root user password (defined at install time) to change to that user. If you type "whoami" you should see "root" as the output.

3.2. You got a mail! §

When you install the system (or upgrade) you will receive an email on root user, you can read it using the "mail" command, it will be an email from Theo De Raadt (founder of OpenBSD) greeting you.

You will notice this email contain hints and has basically the same purpose of my current article you are reading. One important man page to read is afterboot(8).

afterboot(8) man page

3.3. What is a man page? §

If you don't know what a man page is, it's really time to learn because you will need it. When someone say a "man page" it implies "a manual page". Documentation in OpenBSD is done in manual pages related to various software, concepts or C functions.

To read a man page, in a terminal type "man afterboot" and use arrows or page up/down to navigate within the man page. You can read "man man" page to read about man itself.

Previously I wrote "afterboot(8)" but the real man page name is "afterboot", the "(8)" is meant to specify the man page section. Some words can be used in various contexts, that's where man pages sections come into the place. For instance, there are sysctl(2) documenting the system call "sysctl()" while sysctl(8) will give you information about the sysctl command to change kernel settings. You can specify which section you want to read by typing the number before the page name, like in "man 2 sysctl" or "man 8 sysctl".

Man pages are constructed in the same order: NAME, SYNOPSIS, DESCRIPTION..... SEE ALSO..., the section "SEE ALSO" is an important one, it gives you man page references of other pages you may want to read. For example, afterboot(8) will give you hints about doas(1), pkg_add(1), hier(7) and many other pages.

Now, you should be able to use the manual pages.

4. Install a desktop environment §

When you want to install a desktop environment, there will often be a "meta package" which will pull every packages required for the environment to work.

OpenBSD provides a few desktop environments like:

- Gnome 3 => pkg_add gnome

- Xfce => pkg_add xfce

- MATE => pkg_add mate

When you install a package using "pkg_add", you may find a message at the end of the pkg_add output telling you there is a file in /usr/local/share/doc/pkg-readmes/ to read, those files are specifics to packages and contains instructions that should be read before using a package.

The instructions could be about performance, potential limits issues, configuration snippets, how to init the service etc... They are very important to read, and for desktop environment, they will tell you everything you know to get it started.

5. Graphical session §

When you log-in from the xenodm screen (the one where you have a Puffer fish and OpenBSD logo asking login/password), the program xenodm will read your ~/.xsession file, this is where you prepare your desktop and the execute commands. Usually, the first blocking command (that keeps running on foreground) is your window manager, you can put commands before to customize your system or run programs in background.

# disable bell
xset b off

# auto blank after 10 minutes
xset s 600 600

# run xclock and xload
xclock -geometry 75x75-70-0 -padding 1 &
xload -nolabel -update 5 -geometry 75x75-145-0 & 

# load my ~/.profile file to define ENV
. ~/.profile

# display notifications
dunst &

# load changes in X settings
xrdb -merge ~/.Xresources

# turn the screen reddish to reduce blue color
sct 5600

# synchronize copy buffers
autocutsel &

# kdeconnect to control android phone
kdeconnect-indicator &

# reduce sound to not destroy my ears
sndioctl -f snd/1 output.level=0.3 

# compositor for faster windows drawing
picom &

# something for my mouse setup (I can't remember)
xset mouse 1 1
xinput set-prop 8 273 1.1

# run my window manager
fvwm2

6. Configure your shell §

This is a very recurrent question, how to get your shell aliases to be working once you have logged in? In bash, sh and ksh (and maybe other shells), every time you spawn a new interactive shell (in which you can enter commands), the environment variable ENV will be read and if it has a value matching a file path, it will be loaded.

The design to your beloved shell environment set is the following:

- ~/.xsession will source ~/.profile when starting X, inheriting the content to everything run from X

- ~/.profile will export ENV like in "export ENV=~/.myshellfile"

7. CPU frequency auto scaling §

If you run a regular computer (amd64 arch) you will want to run the service "apmd" in automatic mode, it will keep your CPU at lowest frequency and increase the frequency when you have some load, allowing to reduce heat, power usage and noise.

Here are commands to run as root:

rcctl enable apmd
rcctl set apmd flags -A
rcctl start apmd

8. What are -release and -stable? §

To make things simple, the "-release" version is the whole sets of files to install OpenBSD of that release when it's out. Further updates for that release are called -stable branch, if you run "pkg_add -u" to update your packages and "syspatch" to update your base system you will automatically follow -stable (which is fine!). Release is a single point in time of the state of OpenBSD.

9. Quick FAQ §

9.1. Where is steam? §

No steam, it's proprietary and can't run on OpenBSD

9.2. Where is wine? §

No wine, it would require changes into the kernel.

9.3. Does my recent NVIDIA card work? §

No nvidia driver, it would work but with a VESA driver, it will be sluggish and very slow.

9.4. Does the linux emulation work? §

There is no linux emulation.

9.5. I want my favorite program to run on OpenBSD §

If it's not opensource and not using a language like Java or C# that use a Language Virtual Machine allowing abstraction layer to work, it won't work (and most program are not like that).

If it's opensource, it may be possible if all its dependencies are available on OpenBSD.

Get into the ports tree to make things run on OpenBSD

9.6. Can I have sudo? §

OpenBSD ships a sudo alternative named "doas" in the base system but sudo can be installed from packages.

doas man page

doas.conf man page

9.7. How to view the package list? §

You can check the package directory in a mirror or visit

Openports.pl (using the development version of the ports tree)

9.8. What can the virtualization tool do? §

The virtualization system of OpenBSD can run OpenBSD or some linux distributions but without a graphical interface and with only 1 CPU. This mean you will have to configure a serial console to proceed to the installation and then use ssh or the serial console to use your system.

There is qemu in ports but it's not accelerated and won't suit most of people needs because it's terribly terribly slow.

OpenBSD 6.9 packages using IPFS

Written by Solène, on 01 May 2021.
Tags: #openbsd #ipfs

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1. Update 15/07/2021 §

I disable the IPFS service because it's nearly not used and draw too much CPU on my server. It was a nice experiment, thank you very much for the support and suggestions.

2. Introduction §

OpenBSD 6.9 has been released and I decided to extend my IPFS experiment to latest release. This mean you can fetch packages and base sets for 6.9 amd64 now over IPFS.

If you don't know what IPFS is, I recommend you to read my previous articles about IPFS.

Note that it also works for -current / amd64, the server automatically checks for new updates of 6.9 and -current every 8 hours.

3. Benefits §

The benefits is to play with IPFS to understand how it works with a real world use case. Instead of using mirrors to distributes packages, my server is providing the packages and everyone downloading it can also participate into providing data to other IPFS client, this can be seen as a dynamic Bittorrent CDN (Content Delivery Network), instead of making a torrent per file, it's automatic. You certainly wouldn't download each packages as separate torrents files, nor you would download all the packages in a single torrent.

This could reduce the need for mirrors and potentially make faster packages access to people who are far from a mirrors if many people close to that person use IPFS and downloaded the data. This is a great technology that can only be beneficial once it reach a critical mass of adopters.

4. Installing IPFS on OpenBSD §

To make it brief, there are instructions in the provided pkg-readme but I will give a few advice (that I may add to the pkg-readme later).

pkg_add go-ipfs
su -l -s /bin/sh _go-ipfs -c "IPFS_PATH=/var/go-ipfs /usr/local/bin/ipfs init"
rcctl enable go_ipfs

# recommended settings
rcctl set go_ipfs flags --routing=dhtclient --enable-namesys-pubsub

cat <<EOF >> /etc/login.conf
go_ipfs:\
	:openfiles=2048:\
	:tc=daemon:
EOF

rcctl start go_ipfs

Put this in /etc/installurl:

http://k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z.ipns.localhost:8080/pub/OpenBSD

5. Conclusion §

Now, pkg_add will automatically download the packages from IPFS, if more people use it, it will be faster and more resilient than if only my server is distributing the packages.

Have fun and enjoy 6.9 !

If you are worried about security, packages distributed are the same than the one on the mirrors, pkg_add automatically checks the signature in the files against the signify keys available in /etc/signify/ so if pkg_add works, the packages are legitimates.

Use Libreoffice Calc to make 3D models

Written by Solène, on 27 April 2021.
Tags: #fun

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1. Introduction §

Today I will share with you a simple python script turning a 2D picture defined by numbers and colors in a spreadsheet into a 3D model in OpenSCAD.

Project webpage

2. How to install §

Short instructions how to install sheetstruder, I will send some documentation upstream. You need git and python and later you will need openscad and a spreadsheet tool.

git clone https://git.hackers.town/seachaint/sheetstruder.git
cd sheetstruder
python3 -m venv sandbox
. sandbox/bin/activate
python3 -m pip install -r requirements.txt

You will need to be in this shell (you need at least the activate command) to make it work.

3. How to use §

Open a spreadsheet tool that is able to export in format xlsx, type a number to create a solid object of this width (1 = 1 pixel, 2 = 3 pixels because it's mirrored) and put a background color in your cell. Save your file as xlsx.

Run "python3 ./sheetstruder.py yourfile.xlsx > file.scad" and open the file in OpenSCAD, enjoy!

4. Examples §

I made a simple house with grass around, an antenna, cheminey with smoke, a door and window in it.

House in Libreoffice Calc
House in Libreoffice Calc
House rendered in OpenSCAD from the sheetstruder export
House rendered in OpenSCAD from the sheetstruder export

5. More resources §

OpenSCAD website

Port of the week: pup

Written by Solène, on 22 April 2021.
Tags: #internet

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1. Introduction §

Today I will introduce you to the utility "pup" providing CSS selectors filtering for HTML documents. It is a perfect companion to curl to properly fetch only a specific data from an HTML page.

On OpenBSD you can install it with pkg_add pup and check its documentation at /usr/local/share/doc/pup/README.md

pup official project

2. Examples §

pup is quite easy to use once you understand the filters. Let's see a few examples to illustrate practical uses.

2.1. Fetch my blog titles list to a JSON format §

The following command will returns a JSON structure with an array of data from the tags matching "a" tags with in "h4" tags.

curl https://dataswamp.org/~solene/index.html | pup "h4 a json{}"

The output (only an extract here) looks like this:

[
 {
  "href": "2021-04-18-ipfs-bandwidth-mgmt.html",
  "tag": "a",
  "text": "Bandwidth management in go-IPFS"
 },
 {
  "href": "2021-04-17-ipfs-openbsd.html",
  "tag": "a",
  "text": "Introduction to IPFS"
 },
 [truncated]
 {
  "href": "2016-05-02-3.html",
  "tag": "a",
  "text": "How to add a route through a specific interface on FreeBSD 10"
 }
]

2.2. Fetch OpenBSD -current specific changes §

The page https://www.openbsd.org/faq/current.html contains specific instructions that are required for people using OpenBSD -current and you may want to be notified for changes. Using pup it's easy to make a script to compare your last data to see what has been appended.

curl https://www.openbsd.org/faq/current.html | pup "h3 json{}"

Output sample as JSON, perfect for further processing with a scripting language.

[
 {
  "id": "r20201107",
  "tag": "h3",
  "text": "2020/11/07 - iked.conf \u0026#34;to dynamic\u0026#34;"
 },
 {
  "id": "r20210312",
  "tag": "h3",
  "text": "2021/03/12 - IPv6 privacy addresses renamed to temporary addresses"
 },
 {
  "id": "r20210329",
  "tag": "h3",
  "text": "2021/03/29 - [packages] yubiserve replaced with yubikeyedup"
 }
]

I provide a RSS feed for that

3. Conclusion §

There are many possibilities with pup and I won't list them all. I highly recommend reading the README.md file from the project because it's its documentation and explains the syntax for filtering.

Bandwidth management in go-IPFS

Written by Solène, on 18 April 2021.
Tags: #ipfs

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1. Introduction §

In this article I will explain a few important parameters for the reference IPFS node server go-ipfs in order to manage the bandwidth correctly for your usage.

2. Configuration File §

The configuration file of go-ipfs is set by default to $HOME/.ipfs/config but if IPFS_PATH is set it will be $IPFS_PATH/.config

3. Tweaks §

There are many tweaks possible in the configuration file, but there are pros and cons for each one so I can't tell you what values you want. I will rather explain what you can change and in which situation you would want it.

3.1. Connections number §

By default, go-ipfs will keep a number of connections to peers between 600 and 900 and new connections will last at least 20 seconds. This may totally overwhelm your router to have to manage that quantity of TCP sessions.

The HighWater will define the maximum sessions you want to exist, so this may be the most important setting here. On the other hand, the LowWater will define the number of connections you want to keep all the time, so it will drain bandwidth if you keep it high.

I would say if you care about your bandwidth usage, keep the LowWater low like 50 and have the HighWater quite high and a short GracePeriod, this will allow go-ipfs to be quiet when unused but responsive (able to connect to many peers to find a content) when you need it.

Documentation about Swarm.ConnMgr

3.2. DHT Routing §

IPFS use a distributed hash table to find peers (it's the common way to proceed in P2P networks), but your node can act as a client and only fetch the DHT from other peer or be active and distribute it to other peer.

If you have a low power server (CPU) and that you are limited in your bandwidth, you should use the value "dhtclient" to no distribute the DHT. You can configure this in the configuration file or use --routing=dhtclient in the command line.

Documentation about Routing.type

3.3. Reprovider §

3.3.1. Strategy §

This may be the most important choice you have to make for your IPFS node. With the Reprovider.Strategy setting you can choose to be part of the IPFS network and upload data you have locally, only upload data you pinned or upload nothing.

If you want to actively contribute to the network and you have enough bandwidth, keep the default "all" value, so every data available in your data store will be served to clients over IPFS.

If you self host data on your IPFS node but you don't have much bandwidth, I would recommend setting this value to "pinned" so only the data pinned in your IPFS store will be available. Remember that pinned data will never be removed from the store by the garbage collector and files you add to IPFS from the command line or web GUI are automatically pinned, the pinned data are usually data we care about and that we want to keep and/or distribute.

Finally, you can set it to empty and your IPFS node will never upload any data to anyone which could be consider as unfair in a peer to peer network but under some quota limited or high latency connection it would make sense to not upload anything.

Documentation about Reprovider.Strategy

3.3.2. Interval §

While you can choose what kind of data you want your node to relay as a part of the IPFS network, you can choose how often your node will publish the content of the data hold in its data store.

The default is 12 hours, meaning every 12 hours your node will publish the list of everything available for upload to the other peers. If you care about bandwidth and your content doesn't change often, you can increase this value, on the other hand if you may want to publish more often if your data store is rapidly changing.

If you don't want to publish your content, you can set it to "0", then you would still be able to publish it manually using the IPFS command line.

Documentation about Reprovider.Interval

3.4. Gateway management §

If you want to provide your data over a public gateway, you may not want everyone to use this gateway to download IPFS content because of legal concerns, resource limits or you simply don't want that.

You can set Gateway.NoFetch to make your gateway to only distribute files available in the node data store. Meaning it will act as an http·s server for your own data but the gateway can't be used to get any other data. It's a convenient way to publish content over IPFS and make it available from a gateway you trust while keeping control over the data relayed.

Documentation about Gateway.NoFetch

4. Conclusion §

There are many settings here for various use case. I'm running an IPFS node on a dedicated server but also another one at home and they have a very different configuration.

My home connection is limited to 900 kb/s which make IPFS very unfriendly to my ISP router and bandwidth usage.

Unfortunately, go-ipfs doesn't provide an easy way to set download and upload limit, that would be very useful.

Introduction to IPFS

Written by Solène, on 17 April 2021.
Tags: #openbsd #ipfs

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1. introduction to IPFS §

IPFS is a distributed storage network protocol that comes with a public network. Anyone can run a peer and access content from IPFS and then relay the content while it's in your cache.

Gateways are websites used to allow accessing content of IPFS through http, there are several public gateways allowing to get data from IPFS without being a peer.

Every publish content has an unique CID to identify it, we usually add a /ipfs/ to it like in /ipfs/QmRVD1V8eYQuNQdfRzmMVMA6cy1WqJfzHu3uM7CZasD7j1. The CID is unique and if someone add the same file from another peer, they will get the same hash as you.

If you add a whole directory in IPFS, the top directory hash will depend on the hash of its content, this mean if you want to share a directory like a blog, you will need to publish the CID every time you change the content, as it's not practical at all, there is an alternative for making the process more dynamic.

A peer can publish data in a long name called an IPNS. The IPNS string will never change (it's tied to a private key) but you can associate a CID to it and update the value when you want and then tell other peers the value changed (it's called publishing). The IPNS notation used is looking like /ipns/k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z.ipns, you can access an IPNS content with public gateways with a different notation.

- IPNS gateway use example: https://k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z.ipns.dweb.link/

- IPFS gateway use example: https://ipfs.io/ipfs/QmRVD1V8eYQuNQdfRzmMVMA6cy1WqJfzHu3uM7CZasD7j1/

The IPFS link will ALWAYS return the same content because it's a defined hash to a specific resource. The IPNS link can be updated to have a newer CID over time, allowing people to bookmark the location and browse it for updates later.

2. Using a public gateway §

There are many public gateways you can use to fetch content.

Health check of public gateways, useful to pick one

You will find two kind of gateways url, one like "https://$domain/" and other like "https://$something_very_long.ipfs.$domain/", for the first one you need to append your /ipfs/something or /ipns/something requests like in the previous examples. For the latter, in web browser it only works with ipns because web browsers think the CID is a domain and will change the case of the letters and it's not long valid. When using an ipns like this, be careful to change the .ipfs. by .ipns. in the url to tell the gateway what kind of request you are doing.

3. Using your own node §

First, be aware that there is no real bandwidth control mechanism and that IPFS is known to create too many connections that small routers can't handle. On OpenBSD it's possible to mitigate this behavior using queuing. It's possible to use a "lowpower" profile that will be less demanding on network and resources but be aware this will degrade IPFS performance. I found that after a few hours of bootstrapping and reaching many peers, the bandwidth usage becomes less significant but it's may be an issue for DSL connections like mine.

When you create your own node, you can use its own gateway or the command line client. When you request a data that doesn't belong to your node, it will be downloaded from known peers able to distribute the blocks and then you will keep it in cache until your cache reach the defined limited and the garbage collector comes to make some room. This mean when you get a content, you will start distributing it, but nobody will use your node for content you never fetched first.

When you have data, you can "pin" it so it will never be removed from cache, and if you pin a directory CID, the content will be downloaded so you have a whole mirror of it. When you add data to your node, it's automatically pinned by default.

The default ports are 4001 (the one you need to expose over the internet and potentially forwarding if you are behind a NAT), the Web GUI is available at http://localhost:5001/ and the gateway is available at http://localhost:8080/

3.1. Installing the node on OpenBSD §

To make it brief, there are instructions in the provided pkg-readme but I will give a few advice (that I may add to the pkg-readme later).

pkg_add go-ipfs
su -l -s /bin/sh _go-ipfs -c "IPFS_PATH=/var/go-ipfs /usr/local/bin/ipfs init"
rcctl enable go_ipfs

# recommended settings
rcctl set go_ipfs flags --routing=dhtclient --enable-namesys-pubsub

cat <<EOF >> /etc/login.conf
go_ipfs:\
	:openfiles=2048:\
	:tc=daemon:
EOF
rcctl start go_ipfs

You can change the profile to lowpower with "env IPFS_PATH=/var/go-ipfs/ ipfs config profile apply lowpower", you can also list profiles with the ipfs command.

I recommend using queues in PF to limit the bandwidth usage, for my DSL connection I've set a maximum of 450K and it doesn't disrupt my network anymore. I explained how to proceed with queuing and bandwidth limitations in a previous article.

3.2. Installing the node on NixOS §

Installing IPFS is easy on NixOS thanks to its declarative way. The system has a local IPv4 of 192.168.1.150 and a public IP of 136.214.64.44 (fake IP here). it is started with a 50GB maximum for cache. The gateway will be available on the local network on http://192.168.1.150:8080/.

services.ipfs.enable = true;
services.ipfs.enableGC = true;
services.ipfs.gatewayAddress = "/ip4/192.168.1.150/tcp/8080";
services.ipfs.extraFlags = [ "--enable-namesys-pubsub" ];
services.ipfs.extraConfig = {
    Datastore = { StorageMax = "50GB"; };
    Routing = { Type = "dhtclient"; };
};
services.ipfs.swarmAddress = [
        "/ip4/0.0.0.0/tcp/4001"
        "/ip4/136.214.64.44/tcp/4001"
        "/ip4/136.214.64.44/udp/4001/quic"
        "/ip4/0.0.0.0/udp/4001/quic"
];

3.3. Testing your gateway §

Let's say your gateway is http://localhost:8080/ for making simpler incoming examples. If you want to request the data /ipfs/QmRVD1V8eYQuNQdfRzmMVMA6cy1WqJfzHu3uM7CZasD7j1 , you just have to add this to your gateway, like this: http://localhost:8080/ipfs/QmRVD1V8eYQuNQdfRzmMVMA6cy1WqJfzHu3uM7CZasD7j1 and you will get access to your file.

When using ipns, it's quite the same, for /ipns/blog.perso.pw/ you can request http://localhost:8080/ipns/blog.perso.pw/ and then you can browse my blog.

4. OpenBSD experiment §

To make all of this really useful, I started an experiment: distributing OpenBSD amd64 -current and 6.9 both with sets and packages over IPFS. Basically, I have a server making a rsync of both sets once a day, will add them to the local IPFS node, get the CID of the top directory and then publish the CID under an IPNS. Note that I have to create an index.html file in the packages sets because IPFS doesn't handle directory listing very well.

The following examples will have to be changed if you don't use a local gateway, replace localhost:8080 by your favorite IPFS gateway.

You can upgrade your packages with this command:

env PKG_PATH=http://localhost:8080/ipns/k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z/pub/OpenBSD/snapshots/packages/amd64/ pkg_add -Dsnap -u

You can switch to latest snapshot:

sysupgrade -s http://localhost:8080/ipns/k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z/pub/OpenBSD/

While it may be slow to update at first, if you have many systems, running a local gateway used by all your computers will allow to have a cache of downloaded packages, making the whole process faster.

I made a "versions.txt" file in the top directory of the repository, it contains the date and CID of every publication, this can be used to fetch a package from an older set if it's still available on the network (because I don't plan to keep all sets, I have a limited disk).

You can simply use the url http://localhost:8080/ipns/k51qzi5uqu5dmebzq75vx3z23lsixir3cxi26ckl409ylblbjigjb1oluj3f2z/pub/OpenBSD/ in the file /etc/installurl to globally use IPFS for pkg_add or sysupgrade without specifying the url every time.

5. Using DNS §

It's possible to use a DNS entry to associate an IPFS resource to a domain name by using dnslink. The entry would look like:

_dnslink.blog	IN	TXT	"dnslink=/ipfs/somehashhere"

Using an /ipfs/ syntax will be faster to resolve for IPFS nodes but you will need to update your DNS every time you update your content over IPFS.

To avoid manipulating your DNS every so often (you could use an API to automate this by the way), you can use an /ipns/ record.

_dnslink.blog	IN	TXT	"dnslink=/ipns/something"

This way, I made my blog available under the hostname blog.perso.pw but it has no A or CNAME so it work only in an IPFS context (like a web browser with IPFS companion extension). Using a public gateway, the url becomes https://ipfs.io/ipns/blog.perso.pw/ and it will download the last CID associated to blog.perso.pw.

6. Conclusion §

IPFS is a wonderful piece of technology but in practice it's quite slow for DSL users and may not work well if you don't need a local cache. I do really love it though so I will continue running the OpenBSD experiment.

Please write me if you have any feedback or that you use my OpenBSD IPFS repository. I would be interested to know about people's experiences.

7. Interesting IPFS resources §

dweb-primer tutorials for IPFS (very well written)

Official IPFS documentation

IPFS companion for Firefox and Chrom·ium·e

Pinata.cloud is offering IPFS hosting (up to 1 GB for free) for pinned content

Wikipedia over IPFS

OpenBSD website/faq over IPFS (maintained by solene@)

Port of the week: musikcube

Written by Solène, on 15 April 2021.
Tags: #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

Today I will share about the console oriented audio player "musikcube" because I really like it. It has many features while being easy to use for a console player. The feature that really sold it to me is the library management and the rating feature allowing me to rate my files and filter by score. The library is nice to browse, it's easy to filter by pattern and the whole UI is easy to use.

Unfortunately it doesn't come with a man page, so you can check the key binding by typing "?" in it or look at the key bindings menu in the main menu.

Official user guide

Official project website

The package is not yet available on OpenBSD but should arrive after 6.9 release (so it will be in 7.0 release).

Picture of Musikcube playing music from a directory mode display
Picture of Musikcube playing music from a directory mode display

2. A terminal client §

Musikcube is a console client, meaning you start it in a terminal. You can easily switch between menus with Tab, Shift+Tab, Enter and keyboard arrows but you should also check the key bindings for full controls. Note that the mouse is supported!

Once you told musikcube where to look files, you will have access to your library, using numbers from 1 to 6 you can choose how you want the library filtered but 6 will ask which criteria to use, using "directory" will display the file hierarchy which is sometimes nicer to use for badly tagged music files.

You can access to the whole tracks list using "t" and then filter by pattern or sort the list using "Ctrl + s".

3. A server §

When run as musikcube, a daemon mode is started to accept incoming connections on TCP ports 7905 and 7906 for remote API control and transcoding/streaming. This behavior can be disabled in the main menu under the "server setup" choice.

Running it with the binary musikubed binary, there will be no UI started, only a background daemon listening on ports.

4. Android companion app §

Musikcube has a companion app for Android named musikdroid but it only available for download as a file on the github project.

The app has multiples features, it can control the musikcube server for music playing on the remote system, but you can also use it to stream music to your Android device. The song on the musikcube server and android devices can be separated. Even better, songs played on the android devices will be automatically stored for offline (you can tune the cache) and even transcode files to have smaller files for the device.

Look for a .apk file in the assets list of the releases

Easy text transmission from computer to smartphone

Written by Solène, on 25 March 2021.
Tags: #opensource

Comments on Fediverse/Mastodon

1. Introduction §

Today I will share with you a simple way I found to transmit text from my computer to my phone. I often have to do it, to type a password, enter an url, copy/paste a message or whatever reasons.

2. Using QR codes §

The best way to get a text from computer to a smartphone (that I am aware of) is scanning a QR code using the camera. By using the command qrencode (I already wrote about this one), xclip and feh (a picture viewer), it is possible to generate QR code on the fly on the screen.

Is it as simple as running the following command, from a menu or a key binding:

xclip -o | qrencode -o - -t PNG | feh -g 600x600 -Z - 

Using this command, xclip will gives the clipboard to qrencode which will create a PNG file on stdout and then feh will display it on a 600 by 600 window, no temporary file involved here.

Once the picture is displayed on the screen, you can use a scanner program on your phone to gather the content, I found "QR & Barcode Scanner" to be really light, fast and usable with its history, available on F-Droid.

QR & Barcode Scanner on F-Droid

Composing a quite long text on your computer and sharing it to the phone can be done with sending the text to xclip and then generate the QR code.

3. Going further §

When it comes to sharing data between my phone and my computer, I love "primitive ftpd" which is a SFTP/FTP server for Android, it works out of the box and allow secure transfers over Wifi (use SFTP please!).

primitive ftpd on F-Droid

For simple transfers, I use "Share to Computer" that will share a file or a group of files as a zip on a temporary http server, it is then easy to connect to it to save the file.

Share to Computer on F-Droid

For sending SMS through my phone but from my computer, I use the program KDE Connect (it has to be installed on phone and computer), I wanted to write about it for a long time but it's not easy to explain how to get it to work and uneasy to explain its usage. But it allows me to receive phone notifications on my computer and also send SMS. I have simple aliases in my shell like "mom-sms hello are you ?" to ease my use of SMS. When possible, don't use SMS, it's not secure. The program does a lot more than sending SMS, like using the smartphone as a remote touchpad as one example.

KDE Connect on F-Droid

Opensource from an author point of view

Written by Solène, on 23 March 2021.
Tags: #opensource

Comments on Fediverse/Mastodon

Hi, today's article will be a bit different than what you are used to. I am currently writing about my experience as an open source author and "project manager". I recently created a project that, while being extremely small, have seen some people getting involved at various level. I didn't know what it was to be in this position.

Having to deal with multiple people contributing to a project I started for myself on one architecture with a limited set of features is surprisingly hard. I don't say it's boring and that no one should ever do it, but I think I wasn't really prepare to handle this.

I made my best to integrate people wishes while keeping the helm of the project in the right direction, but I had to ask myself many questions.

1. Many questions §

Should I care about what other people need? I could say no to everything proposed if I see no benefit for my use case. I chose to accept some changes that I didn't use because they made sense in some context. But I have to be really careful to accept everything if I want to keep the program sane.

Should I care about other platforms I don't use? Someone proposed me to add some code to support Linux targets, which I don't use, meaning more code I can't test. For the sake of compatibility and avoiding extra work to packagers, I made a very simple solution to fix that, but if someone wanted to port my program to Windows or a platform that would require many many changes, I don't know how I would react.

Too much changing code situation. My program changed A LOT since my initials commits, and now a git blame mostly show no lines from me, this doesn't mean I didn't review changes made by contributors, but I am not as comfortable now that I was initially with my own code. That doesn't mean the new code is wrong, but it doesn't hold my logic in it. I think it's the biggest deal in this situation, I, as the project manager, must say what can go in, what can't and when. It's fine to receive contributions but they shouldn't add complexity or weird algorithms.

2. Accepting changes §

I am not an expert programmer, I don't often write code, and when I do, it's for my own benefit. Opening our work to other implies making it accessible to outsiders, accepting changes and explaining choices.

Many times I reviewed submitted code and replied it wasn't fine, and while it compiles and apply correctly, it's not the right way to do, please rework this in some way to make it better or discard it, but it won't get into the repository. It's not always easy, people can submit code I don't understand sometimes, I still have to review it thoroughly because I can't accept everything sent.

In some way, once people get involved into my projects, they get denatured because they receive thoughts from other, their ideas, their logic, their needs. It's wonderful and scary at the same time. When I publish code, I never expect it to be useful for someone and even less that I could receive new features by emails from strangers.

Be prepared for this is important when you start a project and that you make it open source. I could refuse everything but then I would cut myself from a potential community around my own code, that would be a shame.

3. Responsibility §

This part is not related to my projects (or at least not in this situation) but this is a debate I often think about when reading dramas in open source: is an open source author responsible toward the users?

One way to reply this is that if you publish your content online and accept contributions, this mean you care about users (which then contribute back), but where to draw the limit of what is acceptable? If someone writes an awesome program for themselves and gather a community around it, and then choose to make breaking changes or remove important features, what then? The users are free to fork, the author is free to to whatever they want.

There are no clear responsibility binding contributors and end users, I hope most of the time, contributors think about the end users, but with different philosophies in play sometimes we can end in dilemma between the two groups.

4. Epilogue §

I am very happy to publish open source code and to have contributors, coordinate people, goals and features is not something I expected :)

Please, be cautious with this writing, I only had to face this situation with a couple of contributors, I can't imagine how complicated it can become at a bigger scale!

Securely share a secret using Shamir's secret sharing

Written by Solène, on 21 March 2021.
Tags: #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

I will present you the program ssss (for Shamir's Secret Sharing Scheme), a cryptography program to split a secret into n parts, requiring at least t parts to be recovered (with t <= n).

Shamir Secret Sharing (method is mathematically proven to be secure)

2. Use case §

The project website list a few use cases for real life and I like them, but I will share another use case.

ssss project website

I used to run a community but there was no person in charge apart me, which made me a single point of failure. I decided to make the encrypted backup available to a few kind of trustable community members, and I gave each a secret. There were four members and I made the backup password available only if the four members agreed to share their secrets to get the password. For privacy reasons, I didn't want any of these people to be able to lurk into the backup, at least, if someone had happened to me, they could agree to recover the database only if the four persons agreed on it.

3. How to use §

ssss-split is easy to use, you can only share text with it. So you can use a very long passphrase to encrypt files and share this passphrase into many secrets that you share.

You can install it on OpenBSD using pkg_add ssss.

In the following examples, I will create a simple passphrase and then use the generated secrets to get the original passphrase back.

$ ssss-split -t 3 -n 3
Generating shares using a (3,3) scheme with dynamic security level.
Enter the secret, at most 128 ASCII characters: [Note=>hidden input where I typed "this is a very very long password] Using a 264 bit security level.
1-cfef7c2fcd283133612834324db968ef47e52997d23f9d6eae0ecd8f8d0e898b65
2-e414b5b4de34c0ee2fbb14621201bf16e4a2df70a4b5a16a823888040d332d47a8
3-0d4d2cebcc67851ed93da3c80c58fce745c34d1fb2d1341da29b39a94b98e0f353

When you want to recover a secret, you will have to run ssss-combine and tell it how many secrets you have, they can be provided in any order.

$ ssss-combine -t 3
Enter 3 shares separated by newlines:
Share [1/3]: 2-e414b5b4de34c0ee2fbb14621201bf16e4a2df70a4b5a16a823888040d332d47a8
Share [2/3]: 3-0d4d2cebcc67851ed93da3c80c58fce745c34d1fb2d1341da29b39a94b98e0f353
Share [3/3]: 1-cfef7c2fcd283133612834324db968ef47e52997d23f9d6eae0ecd8f8d0e898b65
Resulting secret: this is a very very long password

4. Tips §

If you want to easily store a secret or share it to a non-IT person (or in a vault), you can create a QR code and then print the picture. QR code has redundancy so if the paper is damaged you can still recover it, it's quite big on a paper so if it fades of you may not lose data and it also checks integrity.

5. Conclusion §

ssss is a wonderful program to share a secret among a few people or put a few secrets here and there for a recovery situation. The program can receive the passphrase on its standard input allowing it to be scripted.

Interesting fact, if you run ssss-combine multiple times on the same text, you always get different secrets, so if you give a secret, no brute force can be used to find which input produced the secret.

How to split a file into small parts

Written by Solène, on 21 March 2021.
Tags: #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

Today I will present the userland program "split" that is used to split a single file into smaller files.

OpenBSD split(1) manual page

2. Use case §

Split will create new files from a single files, but smaller. The original file can be get back using the command cat on all the small files (in the correct order) to recreate the original file.

There are several use cases for this:

- store a single file (like a backup) on multiple medias (floppies, 700MB CD, DVDs etc..)

- parallelize a file process, for example: split a huge log file into small parts to run analysis on each part

- distribute a file across a few people (I have no idea about the use but I like the idea)

3. Usage §

Its usage is very simple, run split on a file or feed its standard input, it will create 1000 lines long files by default. -b could be used to tell a size in kB or MB for the new files or use -l to change the default 1000 lines. Split can also create a new file each time a line match a regex given with -p.

Here is a simple example splitting a file into 1300kB parts and then reassemble the file from the parts, using sha256 to compare checksum of the original and reconstructed files.

solene@kongroo ~/V/pmenu> split -b 1300k pmenu.mp4
solene@kongroo ~/V/pmenu> ls
pmenu.mp4  xab        xad        xaf        xah        xaj        xal        xan
xaa        xac        xae        xag        xai        xak        xam
solene@kongroo ~/V/pmenu> cat x* > concat.mp4
solene@kongroo ~/V/pmenu> sha256 pmenu.mp4 concat.mp4 
SHA256 (pmenu.mp4)  = e284da1bf8e98226dc78836dd71e7dfe4c3eb9c4172861bafcb1e2afb8281637
SHA256 (concat.mp4) = e284da1bf8e98226dc78836dd71e7dfe4c3eb9c4172861bafcb1e2afb8281637
solene@kongroo ~/V/pmenu> ls -l x*
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xaa
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xab
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xac
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xad
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xae
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xaf
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xag
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xah
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xai
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xaj
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xak
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xal
-rw-r--r--  1 solene  wheel   1331200 Mar 21 16:50 xam
-rw-r--r--  1 solene  wheel    810887 Mar 21 16:50 xan

4. Conclusion §

If you ever need to split files into small parts, think about the command split.

For more advanced splitting requirements, the program csplit can be used, I won't cover it here but I recommend reading the manual page for its usage.

csplit manual page

Port of the week: diffoscope

Written by Solène, on 20 March 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

Today I will introduce you to Diffoscope, a command line software to compare two directories. I find it very useful when looking for changes between two extracted tarballs, I use it to compare changes between two version of a program to see what changed.

Diffoscope project website

2. How to install §

On OpenBSD you can use "pkg_add diffoscope", on other systems you may have a package for it, but it could be installed via pip too.

3. Usage §

It is really easy to use, as parameter give the two directories you want to compare, diffoscope will then show the uid, gid, permissions, modification/creation/access time changes between the two directories.

The output on a simple example looks like the following:

--- t/
+++ a/
│   --- t/foo
├── +++ a/foo
│ @@ -1 +1 @@
│ -hello
│ +not hello
│ ├── stat {}
│ │ @@ -1 +1 @@
│ │ -1043 492483 -rw-r--r-- 1 solene wheel 1973218 6 "Mar 20 18:31:08 2021" "Mar 20 18:31:14 2021" "Mar 20 18:31:14 2021" 16384 4 0 t/foo
│ │ +1043 77762 -rw-r--r-- 1 solene wheel 314338 10 "Mar 20 18:31:08 2021" "Mar 20 18:31:18 2021" "Mar 20 18:31:18 2021" 16384 4 0 a/foo

Diffoscope has many flags, if you want to only compare the directories content, you have to use "--exclude-directory-metadata yes".

Using the same example as previously with --exclude-directory-metadata yes, it looks like:

--- t/
+++ a/
│   --- t/foo
├── +++ a/foo
│ @@ -1 +1 @@
│ -hello
│ +not hello

Port of the week: pmenu

Written by Solène, on 12 March 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

This Port of the week will introduce you to a Pie-menu for X11, available on OpenBSD since 6.9 (not released yet). A pie menu is a circle with items spread in the circle, allowing to open other circle with other items in it. I find it very effective for me because I am more comfortable with information spatially organized (my memory is based on spatialization). I think pmenu was designed for a tablet input device using a pen to trigger pmenu.

Pmenu github page

2. Installation §

On OpenBSD, a pkg_add pmenu is enough, but on other systems you should be able to compile it out of the box with a C compiler and the X headers.

3. Configuration §

This part is a bit tricky because the configuration is not obvious. Pmenu takes its configuration on the standard input and then must be piped to a shell.

My configuration file looks like this:

#!/bin/sh

cat <<ENDOFFILE | pmenu | sh &
IMG:/usr/local/share/icons/Adwaita/48x48/legacy/utilities-terminal.png	sakura
IMG:/usr/local/share/icons/Adwaita/48x48/legacy/applets-screenshooter.png	screen_up.sh
Apps
	IMG:/usr/local/share/icons/hicolor/48x48/apps/gimp.png	gimp
	IMG:/home/solene/dev/pmenu/claws-mail.png	claws-mail
	IMG:/usr/local/share/pixmaps/firefox.png	firefox
	IMG:/usr/local/share/icons/hicolor/256x256/apps/keepassxc.png	keepassxc
	IMG:/usr/local/share/icons/hicolor/48x48/apps/chrome.png	chrome
	IMG:/usr/local/share/icons/hicolor/128x128/apps/rclone-browser.png	rclone-browser
Games
	IMG:/home/jeux/slay_the_spire/sts.png	cd /home/jeux/slay_the_spire/ && libgdx-run
	IMG:/home/jeux/Delver/unjar/a/Delver-Logo.png	cd /home/jeux/Delver/unjar/ && /usr/local/jdk-1.8.0/bin/java -Dsun.java2d.dpiaware=true com.interrupt.dungeoneer.DesktopStarter
	IMG:/home/jeux/Dead_Cells/deadcells.png	cd /home/jeux/Dead_Cells/ && hl hlboot.dat
	IMG:/home/jeux/brutal_doom/Doom-The-Ultimate-1-icon.png	cd /home/jeux/doom2/ && gzdoom /home/jeux/brutal_doom/bd21RC4.pk3
Volume
	0%	sndioctl output.level=0
	10%	sndioctl output.level=0.1
	20%	sndioctl output.level=0.2
	30%	sndioctl output.level=0.3
	40%	sndioctl output.level=0.4
ENDOFFILE

The configuration supports levels, like "Apps" or "Games" in this example, that will allow a second level of shortcuts. A text could be used like in Volume, but you can also use images like in other categories. Every blank appearing in the configuration are tabs.

The pmenu itself can be customized by using X attributes, you can learn more about this on the official project page.

4. Video §

I made a short video to show how it looks with the configuration shown here.

Note that pmenu is entirely browseable with the keyboard by using tab / enter / escape to switch to next / validate / exit.

Video demonstrating pmenu in action

Easy spamAssassin with OpenSMTPD

Written by Solène, on 10 March 2021.
Tags: #openbsd #mail

Comments on Fediverse/Mastodon

1. Introduction §

Today I will explain how to setup very easily the anti-spam SpamAssassin and make it work with the OpenSMTPD mail server (OpenBSD default mail server). I will suppose you are already familiar with mail servers.

2. Installation §

We will need two packages to install: opensmtpd-filter-spamassassin and p5-Mail-SpamAssassin. The first one is a "filter" for OpenSMTPD, it's a special meaning in smtpd context, it will run spamassassin on incoming emails and the latter is the spamassassin daemon itself.

2.1. Filter §

As explained in the pkg-readme file from the filter package /usr/local/share/doc/pkg-readmes/opensmtpd-filter-spamassassin , a few changes must be done to the smtpd.conf file. Mostly a new line to define the filter and add "filter "spamassassin"" to lines starting by "listen".

Website of the filter author who made other filters

2.2. SpamAssassin §

SpamAssassin works perfectly fine out of the box, "rcctl enable spamassassin" and "rcctl start spamassassin" is enough to make it work.

Official SpamAssassin project website

3. Usage §

It should really work out of the box, but you can train SpamAssassin what are good mails (called "ham") and what are spam by running the command "sa-learn --ham" or "sa-learn --spam" on directories containing that kind of mail, this will make spamassassin more efficient at filtering by content. Be careful, this command should be run as the same user as the daemon used by SpamAssassin.

In /var/log/maillog, spamassassin will give information about scoring, up to 5.0 (default), a mail is rejected. For legitimate mails, headers are added by spamassassin.

4. Learning §

I use a crontab to run once a day sa-learn on my "Archives" directory holding all my good mails and "Junk" directory which has Spam.

0 2 * * * find /home/solene/maildir/.Junk/cur/     -mtime -1 -type f -exec sa-learn --spam {} +
5 2 * * * find /home/solene/maildir/.Archives/cur/ -mtime -1 -type f -exec sa-learn --ham  {} +

5. Extra configuration §

SpamAssassin is quite slow but can be speeded up by using redis (a key/value database in memory) for storing tokens that help analyzing content of emails. With redis, you would not have to care anymore about which user is running sa-learn.

You can install and run redis by using "pkg_add redis" and "rcctl enable redis" and "rcctl start redis", make sure that your port TCP/6379 is blocked from outside. You can add authentication to your redis server &if you feel it's necessary. I only have one user on my email server and it's me.

You then have to add some content to /etc/mail/spamassassin/local.cf , you may want to adapt to your redis configuration if you changed something.

bayes_store_module  Mail::SpamAssassin::BayesStore::Redis
bayes_sql_dsn       server=127.0.0.1:6379;database=4
bayes_token_ttl 300d
bayes_seen_ttl   8d
bayes_auto_expire 1

Configure a Bayes backend (like redis or SQL)

6. Conclusion §

Restart spamassassin after this change and enjoy. SpamAssassin has many options, I only shared the most simple way to setup it with opensmtpd.

Implement a «Command not found» handler in OpenBSD

Written by Solène, on 09 March 2021.
Tags: #openbsd

Comments on Fediverse/Mastodon

1. Introduction §

On many Linux systems, there is a special program run by the shell (configured by default) that will tell you which package provide a command you tried to run but is not available in $PATH. Let's do the same for OpenBSD!

2. Prerequisites §

We will need to install the package pkglocate to find binaries.

# pkg_add pkglocate

We will also need a file /usr/local/bin/command-not-found executable with this content:

#!/bin/sh

CMD="$1"

RESULT=$(pkglocate */bin/${CMD} */sbin/${CMD} | cut -d ':' -f 1)

if [ -n "$RESULT" ]
then
    echo "The following package(s) contain program ${CMD}"
    for result in $RESULT
    do
        echo "    - $result"
    done
else
    echo "pkglocate didn't find a package providing program ${CMD}"
fi

3. Configuration §

Now, we need to configure the shell to run this command when it detects an error corresponding to an unknown command. This is possible with bash, zsh or fish at least.

3.1. Bash configuration §

Let's go with bash, add this to your bash configuration file

command_not_found_handle()
{
    /usr/local/bin/command-not-found "$1"
}

3.2. Fish configuration §

function fish_command_not_found
    /usr/local/bin/command-not-found $argv[1]
end

3.3. ZSH configuration §

function command_not_found_handler()
{
    /usr/local/bin/command-not-found "$1"
}

4. Trying it §

Now that you configured your shell correctly, if you run a command in your shell that isn't available in your PATH, you may have either a success with a list of packages giving the command or that the command can't be found in any package (unlucky).

This is a successful output that found the program we were trying to run.

$ pup
The following package(s) contain program pup
    - pup-0.4.0p0

This is a result showing that no package found a program named "steam".

$ steam
pkglocate didn't find a package providing program steam

Top 12 best opensource games available on OpenBSD

Written by Solène, on 07 March 2021.
Tags: #openbsd #gaming

Comments on Fediverse/Mastodon

1. Introduction §

This article features the 12 best games (in my opinion) in term of quality and fun available in OpenBSD packages. The list only contains open source games that you can install out of the box. This means that game engines requiring proprietary (or paid) game assets are not part of this list.

2. Tales of Maj'Eyal §

Tome4 is a rogue-like game with many classes, many races, lot of areas to explore. There are fun pieces of lore to find and read if it's your thing, you have to play it many times to unlock everything. Note that while the game is open source, there are paid extensions requiring an online account on the official website, this is not mandatory to play or finish the game.

# pkg_add tome4
$ tome4

Tales of Maj'Eyal official website

Tales of Maj
Tales of Maj'Eyal screenshot

3. OpenTTD §

This famous game is a free reimplementation of the Transport Tycoon game. Build roads, rails, make huge trains networks with signals, transports materials from extraction to industries and then deliver goods to cities to make them grow. There is a huge community and many mods, and the game can be played in multiplayer. Also available on Android.

# pkg_add openttd
$ openttd

OpenTTD official website

[Peertube video] OpenTTD

OpenTTD screenshot
OpenTTD screenshot

4. The Battle for Wesnoth §

Wesnoth is a turn based strategy game based on hexagons. There are many races with their own units. The game features a full set of campaign for playing solo but also include multiplayer. Also available on Android.

# pkg_add wesnoth
$ wesnoth

The Battle for Wesnoth official website

Wesnoth screenshot
Wesnoth screenshot

5. Endless Sky §

This game is about space exploration, you are captain of a ship and you can get missions, enhance your ship, trade goods over the galaxy or fight enemies. There is a learning curve to enjoy it because it's quite hard to understand at first.

# pkg_add endless-sky
$ endless-sky

Endless Sky official website

Endless sky screenshot
Endless sky screenshot

6. OpenRA §

Open Red Alert, the 100% free reimplementation of the engine AND assets of Red Alert, Command and Conquer and Dune. You can play all these games from OpenRA, including multiplayer. Note that there are no campaign, you can play skirmish alone with bots or in multiplayer. Campaigns (and cinematics) could be played using the original games files (from OpenRA launcher), as the games have been published as freeware a few years ago, one can find them for free and legally.

# pkg_add openra
$ openra
wait for instructions to download the assets of the game you want to play

OpenRA official website

[Peertube video] Red Alert

Red Alert screenshot
Red Alert screenshot

7. Cataclysm: Dark Days Ahead §

Cataclysm DDA is a game in which you awake in a zombie apocalypse and you have to survive. The game is extremely complete and allow many actions/combinations like driving vehicles, disassemble electronics to build your own devices and many things I didn't try yet. The game is turn based and 2D from top, I highly recommend reading the manual and how-to because the game is hard. You can also create your character when you start a game, which will totally change the game experience because of your characters attributes and knowledge.

# pkg_add cataclysm-dda
$ cataclysm-dda

Cataclysm: Dark Days Ahead official website

Cataclysm DDA screenshot
Cataclysm DDA screenshot

8. Taisei §

Taisei is a bullet hell game in the Touhou universe. Very well done, extremely fun, multiple characters to play with an alternative mechanic of each character.

# pkg_add taisei
$ taisei

Taisei official website

[Peertube video] Taisei

Taisei screenshot
Taisei screenshot

9. The Legend of Zelda: Return of the Hylian SE §

There is a game engine named Solarus dedicated to write Zelda like games, and Zelda RotH is a game based on this. Nothing special to say, it's a 2D Zelda game, very well done with a new adventure.

# pkg_add zelda_roth_se
$ zelda_roth_se

Zelda RotH official website

ROTH screenshot
ROTH screenshot

10. Shapez.io §

This game is about making industries from shapes and colors in order to deliver what you are asked to produce in the most efficient manner, this game is addictive and easy to understand thanks to the tutorial when you start the game.

# pkg_add shapezio
$ /usr/local/bin/electron /usr/local/share/shapez.io/index.html

Shapez.io official website

Shapez.io screenshot
Shapez.io screenshot

11. OpenArena §

OpenArena is a Quake 3 reimplementation, including assets. It's like Quake 3 but it's not Quake 3 :)

# pkg_add openarena
$ openarena

OpenArena official website

Openarena screenshot
Openarena screenshot

12. Xonotic §

This is a fast paced arena FPS game with beautiful graphics, many weapons with two modes of fire and many games modes. Reminds me a lot Unreal Tournament 2003.

# pkg_add xonotic
$ xonotic

Xonotic official website

Xonotic screenshot
Xonotic screenshot

13. Hyperrogue §

This game is a rogue like (every run is different than last one) in which you move from hexagone to hexagone to get points, each biome has its own characteristics, like a sand biome in which you have to gather spice and you must escape sand worms :-) . The game is easy to play, turn by turn and has unusual graphics because of the non-euclidian nature of its world. I recommend reading the game manual because the first time I played it I really disliked it by missing most of the game mechanics... Also available on Android!

Hyperrogue official website

Hyperrogue screenshot
Hyperrogue screenshot

14. And many others §

Here is a list of games I didn't include but at also worth being played: 0ad, Xmoto, Freedoom, The Dark Mod, Freedink, crack-attack, witchblast, flare, vegastrike and many others.

List of games available on OpenBSD

Port of the week: checkrestart

Written by Solène, on 02 March 2021.
Tags: #openbsd #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

This article features the very useful program "checkrestart" which is OpenBSD specific. The purpose of checkrestart is to display which programs and their according PID for which the binaries doesn't exist anymore.

Why would their binary be absent? The obvious case is that the program was removed, but what it is really good at, is when you upgrade a package with running binaries, the old binary is deleted and the new binary installed. In that case, you will have to stop all the running binaries and restart them. Hence the name "checkrestart".

2. Installation §

Installing it is as simple as running pkg_add checkrestart

3. Usage §

This is simple too, when you run checkrestart, you will have a list of PID numbers with the binary name.

For example, on my system, checkrestart gives me information about what programs got updated that I should restart to run the new binary.

69575	lagrange
16033	lagrange
9664	lagrange
77211	dhcpleased
6134	dhcpleased
21860	dhcpleased

4. Real world usage §

If you run OpenBSD -stable, you will want to use checkrestart after running pkg_add -u. After a package update, most often related to daemons, you will have to restart the related services.

On my server, in my daily script updating packages and running syspatch, I use it to automatically restart some services.

checkrestart | grep php && rcctl restart php-fpm
checkrestart | grep postgres && rcctl restart postgresql
checkrestart | grep nginx && rcctl restart nginx

5. Other Operating System §

I've been told that checkrestart is also available on FreeBSD as a package! The output may differ but the use is the same.

On Linux, a similar tool exists under the name "needrestart", at least on Debian and Gentoo.

Port of the week: shapez.io - a libre factory gaming

Written by Solène, on 26 February 2021.
Tags: #openbsd #openbsd70 #gaming #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

I would like to introduce you to a very nice game I discovered a few months ago, its name is Shapez.io and is a "factory" game, a genre popularized by the famous game Factorio. In this game you will have to extract shapes and colors and rework the shapez, mix colors and mix the whole thing together to produce wanted pieces.

2. The game §

The gameplay is very cool, the early game is an introduction to the game mechanics, you can extract shapes, cut them rotate pieces, merge conveys belts into one, paint shapes etc... and logic circuits!

In those games, you will have to learn how to make efficient factories and mostly "tile-able" installations. A tile-able setup means that if you copy a setup and paste it next to it, it will be bigger and functional, meaning you can extend it to infinity (except that the input conveyors will starve at some point).

It can be quite addictive to improve your setups over and over. This game is non violent and doesn't require any reflex but you need to think. You can't loose, it's between a puzzle and a management game.

Compact tile-able painting setup (may spoil if you want to learn yourself)
Compact tile-able painting setup (may spoil if you want to learn yourself)

3. Where to get it §

On OpenBSD since version 6.9 (not released yet when I publish this) you can install the package shapezio and find a launcher in your desktop environment Game menu.

I also compiled a web version that you can play in your web browser (I discourage using Firefox due to performance..) without installing it, it's legal because the game is open source :)

Play shapez.io in the web browser

The game is also sold on Steam, pre-compiled and ready to run, if you prefer it, it's also a nice way to support the developer.

shapez.io on Steam

4. More content §

Official website

Youtube video of "Real civil engineer" explaining the game

Nginx as a TCP/UDP relay

Written by Solène, on 24 February 2021.
Tags: #openbsd #nginx #networking

Comments on Fediverse/Mastodon

1. Introduction §

In this tutorial I will explain how to use Nginx as a TCP or UDP relay as an alternative to Haproxy or Relayd. This mean nginx will be able to accept requests on a port (TCP/UDP) and relay it to another backend without knowing about the content. It also permits to negociates a TLS session with the client and relay to a non-TLS backend. In this example I will explain how to configure Nginx to accept TLS requests to transmit it to my Gemini server Vger, Gemini protocol has TLS as a requirement.

I will explain how to install and configure Nginx and how to parse logs to obtain useful information. I will use an OpenBSD system for the examples.

It is important to understand that in this context Nginx is not doing anything related to HTTP.

2. Installation §

On OpenBSD we need the package nginx-stream, if you are unsure about which package is required on your system, search which package provide the file ngx_stream_module.so . To enable Nginx at boot, you can use rcctl enable nginx.

Nginx stream module core documentation

Nginx stream module log documentation

3. Configuration §

The default configuration file for nginx is /etc/nginx/nginx.conf , we will want it to listen on port 1965 and relay to 127.0.0.1:11965.

worker_processes  1;

load_module modules/ngx_stream_module.so;

events {
   worker_connections 5;
}

stream {
    log_format basic '$remote_addr $upstream_addr [$time_local] '
                     '$protocol $status $bytes_sent $bytes_received '
                     '$session_time';

    access_log logs/nginx-access.log basic;

    upstream backend {
        hash $remote_addr consistent;
        server 127.0.0.1:11965;
    }
    server {
        listen 1965 ssl;
        ssl_certificate /etc/ssl/perso.pw:1965.crt;
        ssl_certificate_key /etc/ssl/private/perso.pw:1965.key;
        proxy_pass backend;
    }
}

In the previous configuration file, the backend defines the destination, multiples servers could be defined, with weights and timeouts, there is only one in this example.

The server block will tell on which port Nginx should listen and if it has to handle TLS (which is named ssl because of history), usual TLS configuration can be used here, then for a request, we have to tell to which backend Nginx have to relay the connections.

The configuration file defines a custom log format that is useful for TLS connections, it includes remote host, backend destination, connection status, bytes transffered and duration.

4. Log parsing §

4.1. Using awk to calculate time performance §

I wrote a quite long shell command parsing the log defined earlier that display the number of requests, and median/min/max session time.

$ awk '{ print $NF }' /var/www/logs/nginx-access.log | sort -n |  awk '{ data[NR] = $1 } END { print "Total: "NR" Median:"data[int(NR/2)]" Min:"data[2]" Max:"data[NR] }'
Total: 566 Median:0.212 Min:0.000 Max:600.487

4.2. Find bad clients using awk §

Sometimes in the logs there are clients that obtains a status 500, meaning the TLS connection haven't been established correctly. It may be some scanner that doesn't try a TLS connection, if you want to get statistics about those and see if it would be worth to block them if they do too many attempt, it is easy to use awk to get the list.

awk '$(NF-3) == 500 { print $1 }' /var/www/logs/nginx-access.log

4.3. Using goaccess for real time log visualization §

It is also possible to use the program Goaccess to view logs in real time with many information, it is really an awesome program.

goaccess --date-format="%d/%b/%Y" \
         --time-format="%H:%M:%S" \
         --log-format="%h %r [%d:%t %^] TCP %s %^ %b %L" /var/www/logs/nginx-access.log

Goaccess official website

5. Conclusion §

I was using relayd before trying Nginx with stream module, while relayd worked fine it doesn't provide any of the logs Nginx offer. I am really happy with this use of Nginx because it is a very versatile program that shown to be more than a http server over time. For a minimal setup I would still recommend lighter daemon such as relayd.

Port of the week: catgirl irc client

Written by Solène, on 22 February 2021.
Tags: #openbsd70 #openbsd #irc #catgirl #portoftheweek

Comments on Fediverse/Mastodon

1. Introduction §

In this Port of the Week I will introduce you to the IRC client catgirl. While there are already many IRC clients available (and good ones), there was a niche that wasn't filled yet, between minimalism (ii, irCII) and full featured clients (irssi, weechat) in the terminal world. Here comes catgirl, a simple IRC client coming with enough features to be comfortable to use for heavy IRC users.

Catgirl has the following features: tab completion, split scrolling, URL detection, nick coloring, ignores filter. On the other hand, it doesn't support non-TLS networks, CCTP, multi networks or dynamic configuration. If you want to use catgirl with multiples networks, you have to run it once per network.

Catgirl will be available as a package in OpenBSD starting with version 6.9.

OpenBSD security bonus: catgirl features a very good use of unveil to reduce file system access to the minimum required (configuration+logs+certs), reducing the severity of an exploit. It also has a restricted mode when using the -R parameter that reduce features like notifications or url handling and tight the pledge list (allowing systems calls).

Catgirl official website

Catgirl screenshot
Catgirl screenshot

2. Configuration §

A simple configuration file to connect to the irc.tilde.chat server would look like the following file that must be stored under ~/.config/catgirl/tilde

nick = solene_nickname
real = Solene
host = irc.tilde.chat
join = #foobar-channel

You can then run catgirl and use the configuration file but passing the config file name as parameter.

$ catgirl tilde

3. Usage and tips §

I recommend reading catgirl man page, everything is well explained there. I will cover most basics needs here.

Catgirl man page

Catgirl only display one window at a time, it is not possible to split the display, but if you scroll up you will see the last displayed lines and the text stream while keeping the upper part displaying the history, it is a neat way to browse the history without cutting yourself from what's going on in the channel.

Channels can be browsed from keyboard using Ctrl+N or Ctrl+P like in Irssi or by typing /window NUMBER, with number being the buffer number. Alt+NUMBER could also be used to switch directly to buffer NUMBER.

Searches in buffer could be used by typing a word in your input and using Ctrl+R to search backward or Ctrl+S for searching forward (given you are in the history of course).

Finally, my most favorite feature which is missing in minimal clients is Alt+A, jumping to next buffers I have to read (also yes, catgirl keep a line with information about how many messages in channels since last time you didn't read them). Even better, when you press alt+A while there is nothing to read, you jump back to the channel you manually selected last, this allow to quickly read what you missed and return to the channel you spend all your time on.

4. Conclusion §

I really love this IRC client, it replaced Irssi that I used for years really easily because most of the key bindings are the same, but I am also very happy to use a client that is a lot safer (on OpenBSD). It can be used with tmux for persistence but also connect to multiple servers and make it manageable.

Full list of services offered by a default OpenBSD installation

Written by Solène, on 16 February 2021.
Tags: #openbsd70 #openbsd #unix

Comments on Fediverse/Mastodon

1. Introduction §

This article is about giving a short description of EVERY service available as part of an OpenBSD default installation (= no package installed).

From all this list, the following list is started by default: cron, dhcpleased, pflogd, sndiod, openssh, ntpd, slaacd, resolvd, sshd, spamlogd, syslogd and smtpd. Network related daemons smtpd (localhost only), openssh and ntpd (as a client) are running.

2. Service list §

I extracted the list of base install services by looking at /etc/rc.conf.

$ grep _flags /etc/rc.conf | cut -d '_' -f 1

2.1. amd §

This daemon is used to automatically mount a remote NFS server when someone wants to access it, it can provide a replacement in case the file system is not reachable. More information using "info amd".

amd man page

2.2. apmd §

This is the daemon responsible for frequency scaling. It is important to run it on workstation and especially on laptop, it can also trigger automatic suspend or hibernate in case of low battery.

apmd man page

apm man page

2.3. bgpd §

This is a BGP daemon that is used by network routers to exchanges about routes with others routers. This is mainly what makes the Internet work, every hosting company announces their IP ranges and how to reach them, in returns they also receive the paths to connect to all others addresses.

OpenBGPD website

2.4. bootparamd §

This daemon is used for diskless setups on a network, it provides information about the client such as which NFS mount point to use for swap or root devices.

Information about a diskless setup

2.5. cron §

This is a daemon that will read from each user cron tabs and the system crontabs to run scheduled commands. User cron tabs are modified using crontab command.

Cron man page

Crontab command

Crontab format

2.6. dhcpd §

This is a DHCP server used to automatically provide IPv4 addresses on an network for systems using a DHCP client.

2.7. dhcpleased §

This is the new default DHCPv4 client service. It monitors multiples interfaces and is able to handle more complicated setup than dhclient.

dhcpleased man page

2.8. dhcrelay §

This is a DHCP requests relay, used to on a network interface to relay the requests to another interface.

2.9. dvmrpd §

This daemon is a multicast routing daemon, in case you need multicast spanning to deploy it outside of your local LAN. This is mostly replaced by PIM nowadays.

2.10. eigrpd §

This daemon is an Internal gateway link-state routing protocol, it is like OSPF but compatible with CISCO.

2.11. ftpd §

This is a FTP server providing many features. While FTP is getting abandoned and obsolete (certainly because it doesn't really play well with NAT) it could be used to provide read/write anonymous access on a directory (and many other things).

ftpd man page

2.12. ftpproxy §

This is a FTP proxy daemon that one is supposed to run on a NAT system, this will automatically add PF rules to connect an incoming request to the server behind the NAT. This is part of the FTP madness.

2.13. ftpproxy6 §

Same as above but for IPv6. Using IPv6 behind a NAT make no sense.

2.14. hostapd §

This is the daemon that turns OpenBSD into a WiFi access point.

hostapd man page

hostapd configuration file man page

2.15. hotplugd §

hotplugd is an amazing daemon that will trigger actions when devices are connected or disconnected. This could be scripted to automatically run a backup if some conditions are met like an usb disk inserted matching a known name or mounting a drive.

hotplugd man page

2.16. httpd §

httpd is a HTTP(s) daemon which supports a few features like fastcgi support, rewrite and SNI. While it doesn't have all the features a web server like nginx has, it is able to host some PHP programs such as nextcloud, roundcube mail or mediawiki.

httpd man page

httpd configuration file man page

2.17. identd §

Identd is a daemon for the Identification Protocol which returns the login name of a user who initiatied a connection, this can be used on IRC to authenticate which user started an IRC connection.

2.18. ifstated §

This is a daemon monitoring the state of network interfaces and which can take actions upon changes. This can be used to trigger changes in case of an interface losing connectivity. I used it to trigger a route change to a 4G device in case a ping over uplink interface was failing.

ifstated man page

ifstated configuration file man page

2.19. iked §

This daemon is used to provide IKEv2 authentication for IPSec tunnel establishment.

OpenBSD FAQ about VPN

2.20. inetd §

This daemon is often forgotten but is very useful. Inetd can listen on TCP or UDP port and will run a command upon connection on the related port, incoming data will be passed as standard input of the program and program standard output will be returned to the client. This is an easy way to turn a program into a network program, it is not widely used because it doesn't scale well as the whole process of running a new program upon every connection can push a system to its limit.

inetd man page

2.21. isakmpd §

This daemon is used to provide IKEv1 authentication for IPSec tunnel establishment.

2.22. iscsid §

This daemon is an iSCSI initator which will connect to an iSCSI target (let's call it a network block device) and expose it locally as a /dev/vcsi device. OpenBSD doesn't provide a target iSCSI daemon in its base system but there is one in ports.

2.23. ldapd §

This is a light LDAP server, offering version 3 of the protocol.

ldap client man page

ldapd daemon man page

ldapd daemon configuration file man page

2.24. ldattach §

This daemon allows to configure programs that are exposed as a serial port, such as gps devices.

2.25. ldomd §

This daemon is specific to the sparc64 platform and provide services for dom feature.

2.26. lockd §

This daemon is used as part of a NFS environment to support file locking.

2.27. ldpd §

This daemon is used by MPLS routers to get labels.

2.28. lpd §

This daemon is used to manage print access to a line printer.

2.29. mountd §

This daemon is used by remote NFS client to give them information about what the system is currently offering. The command showmount can be used to see what mountd is currently exposing.

mountd man page

showmount man page

2.30. mopd §

This daemon is used to distribute MOP images, which seem related to alpha and VAX architectures.

2.31. mrouted §

Similar to dvmrpd.

2.32. nfsd §

This server is used to service the NFS requests from NFS client. Statistics about NFS (client or server) can be obtained from the nfsstat command.

nfsd man page

nfsstat man page

2.33. npppd §

This daemon is used to establish connection using PPP but also to create tunnels with L2TP, PPTP and PPPoE. PPP is used by some modems to connect to the Internet.

2.34. nsd §

This daemon is an authoritative DNS nameserver, which mean it is holding all information about a domain name and about the subdomains. It receive queries from recursive servers such as unbound / unwind etc... If you own a domain name and you want to manage it from your system, this is what you want.

nsd man page

nsd configuration file man page

2.35. ntpd §

This daemon is a NTP service that keep the system clock at the correct time, it can use ntp servers or sensors (like GPS) as time source but also support using remote servers to challenge the time sources. It can acts a daemon to provide time to other NTP client.

ntpd man page

2.36. ospfd §

It is a daemon for the OSPF routing protocol (Open Shortest Path First).

2.37. ospf6d §

Same as above for IPv6.

2.38. pflogd §

This daemon is receiving packets from PF matching rules with a "log" keyword and will store the data into a logfile that can be reused with tcpdump later. Every packet in the logfile contains information about which rule triggered it so it is very practical for analysis.

pflogd man page

tcpdump

2.39. portmap §

This daemon is used as part of a NFS environment.

2.40. rad §

This daemon is used on IPv6 routers to advertise routes so client can automatically pick up routes.

2.41. radiusd §

This daemon is used to offer RADIUS protocol authentication.

2.42. rarpd §

This daemon is used for diskless setups in which it will help associating an ARP address to an IP and hostname.

Information about a diskless setup

2.43. rbootd §

Per the man page, it says « rbootd services boot requests from Hewlett-Packard workstation over LAN ».

2.44. relayd §

This daemon is used to accept incoming connections and distribute them to backend. It supports many protocols and can act transparently, its purpose is to have a front end that will dispatch connections to a list of backend but also verify backend status. It has many uses and can also be used in addition to httpd to add HTTP headers to a request, or apply conditions on HTTP request headers to choose a backend.

relayd man page

relayd control tool man page

relayd configuration file man page

2.45. resolvd §

This daemon is used to manipulate the file /etc/resolv.conf depending on multiple factors like configured DNS or stragegy change in unwind.

resolvd man page

2.46. ripd §

This is a routing daemon using an old protocol but widely supported.

2.47. route6d §

Same as above but for IPv6.

2.48. sasyncd §

This daemon is used to keep IPSec gateways synchronized in case of a fallback required. This can be used with carp devices.

2.49. sensorsd §

This daemon gathers monitoring information from the hardware like temperature or disk status. If a check exceeds a threshold, a command can be run.

sensorsd man page

sensorsd configuration file man page

2.50. slaacd §

This service is a daemon that will automatically pick up auto IPv6 configuration on the network.

2.51. slowcgi §

This daemon is used to expose a CGI program as a fastcgi service, allowing httpd HTTP server to run CGI. This is an equivalent of inetd but for fastcgi.

slowcgi man page

2.52. smtpd §

This daemon is the SMTP server that will be used to deliver mails locally or to remote email server.

smtpd man page

smtpd configuration file man page

smtpd control command man page

2.53. sndiod §

This is the daemon handling sound from various sources. It also support sending local sound to a remote sndiod server.

sndiod man page

sndiod control command man page

mixerctl man page to control an audio device

OpenBSD FAQ about multimedia devices

2.54. snmpd §

This daemon is a SNMP server exposing some system metrics to SNMP client.

snmpd man page

snmpd configuration file man page

2.55. spamd §

This daemon acts as a fake server that will delay or block or pass emails depending on some rules. This can be used to add IP to a block list if they try to send an email to a specific address (like a honeypot), pass emails from servers within an accept list or delay connections for unknown servers (grey list) to make them and reconnect a few times before passing the email to the SMTP server. This is a quite effective way to prevent spam but it becomes less relevant as sender use whole ranges of IP to send emails, meaning that if you want to receive an email from a big email server, you will block server X.Y.Z.1 but then X.Y.Z.2 will retry and so on, so none will pass the grey list.

2.56. spamlogd §

This daemon is dedicated to the update of spamd whitelist.

2.57. sshd §

This is the well known ssh server. Allow secure connections to a shell from remote client. It has many features that would gain from being more well known, such as restrict commands per public key in the ~/.ssh/authorized_keys files or SFTP only chrooted accesses.

sshd man page

sshd configuration file man page

2.58. statd §

This daemon is used in NFS environment using lockd in order to check if remote hosts are still alive.

2.59. switchd §

This daemon is used to control a switch pseudo device.

switch pseudo device man page

2.60. syslogd §

This is the logging server that receives messages from local programs and store them in the according logfile. It can be configured to pipe some messages to command, program like sshlockout uses this method to learn about IP that must be blocked, but can also listen on the network to aggregates logs from other machines. The program newsyslog is used to rotate files (move a file, compress it and allow a new file to be created and remove too old archives). Script can use the command logger to send text to syslog.

syslogd man page

syslogd configuration file man page

newsyslog man page

logger man page

2.61. tftpd §

This daemon is a TFTP server, used to provide kernels over the network for diskless machines or push files to appliances.

Information about a diskless setup

2.62. tftpproxy §

This daemon is used to manipulate the firewall PF to relay TFTP requests to a TFTP server.

2.63. unbound §

This daemon is a recursive DNS server, this is the kind of server listed in /etc/resolv.conf whose responsibility is to translate a fully qualified domain name into the IP address behind, asking one server at a time, for example, to ask www.dataswamp.org server, it is required to ask the .org authoritative server where is the authoritative server for dataswamp (within .org top domain), then dataswamp.org DNS server will be asked what is the address of www.dataswamp.org. It can also keep queries in cache and validates the queries and replies, it is a good idea to have such a server on a LAN with many client to share the queries cache.

unbound man page

unbound configuration file man page

2.64. unwind §

This daemon is a local recursive DNS server that will make its best to give valid replies, it is designed for nomad users that may encounter hostile environments like captive portals or dhcp offered DNS server preventing DNSSEC to work etc.. Unwind polls a few DNS sources (recursive from root servers, provided by dns, stub or DNS over TLS server from configuration file) regularly and choose the fastest. It will also act as a local cache and can't listen on the network to be used by other clients. It also supports a list of blocked domains as input.

unwind man page

unwind configuration file man page

unwind control command man page

2.65. vmd §

This is the daemon that allow to run virtual machines using vmm. As of OpenBSD 6.9 it is capable of running OpenBSD and Linux guests without graphical interface and only one core.

vmd man page

vmd configuration file man page

vmd control command man page

vmm driver man page

OpenBSD FAQ about virtualization

2.66. watchdogd §

This daemon is used to trigger watchdog timer devices if any.

2.67. wsmoused §

This daemon is used to provide a mouse support to the console.

2.68. xenodm §

This daemon is used to start the X server and allow users to authenticate themselves and log in their session.

xenodm man page

2.69. ypbind §

This daemon is used with a Yellow Page (YP) server to keep and maintain a binding information file.

2.70. ypldap §

This daemon offers a YP service using a LDAP backend.

2.71. ypserv §

This daemon is a YP server.

What security does a default OpenBSD installation offer?

Written by Solène, on 14 February 2021.
Tags: #openbsd70 #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

In this text I will explain what makes OpenBSD secure by default when you install it. Do not take this for a security analysis, but more like a guide to help you understand what is done by OpenBSD to have a secure environment. The purpose of this text is not to compare OpenBSD to other OSes but to say what you can honestly expect from OpenBSD.

There are no security without a threat model, I always consider the following cases: computer stolen at home by a thief, remote attacks trying to exploit running services, exploit of user network clients.

2. Security matters §

Here is a list of features that I consider important for an operating system security. While not every item from the following list are strictly security features, they help having a strict system that prevent software to misbehave and lead to unknown lands.

In my opinion security is not only about preventing remote attackers to penetrate the system, but also to prevent programs or users to make the system unusable.

2.1. Pledge / unveil on userland §

Pledge and unveil are often referred together although they can be used independently. Pledge is a system call to restrict the permissions of a program at some point in its source code, permissions can't be get back once pledge has been called. Unveil is a system call that will hide all the file system to the process except the paths that are unveiled, it is possible to choose what permissions is allowed for the paths.

Both a very effective and powerful surgical security tools but they require some modification within the source code of a software, but adding them requires a deep understanding on what the software is doing. It is not always possible to forbid some system calls to a software that requires to do almost anything, software designed with privilege separation are better candidate for a proper pledge addition because each part has its own job.

Some software in packages have received pledge or/and unveil support, like Chromium or Firefox for the most well known.

OpenBSD presentation about Unveil (BSDCan2019)

OpenBSD presentation of Pledge and Unveil (BSDCan2018)

2.2. Privilege separation §

Most of the base system services used within OpenBSD runs using a privilege separation pattern. Each part of a daemon is restricted to the minimum required. A monolithic daemon would have to read/write files, accept network connections, send messages to the log, in case of security breach this allows a huge attack surface. By separating a daemon in multiple parts, this allow a more fine grained control of each workers, and using pledge and unveil system calls, it's possible to set limits and highly reduce damage in case a worker is hacked.

2.3. Clock synchronization §

The daemon server is started by default to keep the clock synchronized with time servers. A reference TLS server is used to challenge the time servers. Keeping a computer with its clock synchronized is very important. This is not really a security feature but you can't be serious if you use a computer on a network without its time synchronized.

2.4. X display not as root §

If you use the X, it drops privileges to _x11 user, it runs as unpriviliged user instead of root, so in case of security issue this prevent an attacker of accessing through a X11 bug more than what it should.

2.5. Resources limits §

Default resources limits prevent a program to use too much memory, too many open files or too many processes. While this can prevent some huge programs to run with the default settings, this also helps finding file descriptor leaks, prevent a fork bomb or a simple daemon to steal all the memory leading to a crash.

2.6. W^X §

Most programs on OpenBSD aren't allowed to map memory with Write AND Execution bit at the same time (W^X means Write XOR Exec), this can prevents an interpreter to have its memory modified and executed. Some packages aren't compliant to this and must be linked with a specific library to bypass this restriction AND must be run from a partition with the "wxallowed" option.

OpenBSD presentation « Kernel W^X Improvements In OpenBSD »

2.7. Only one reliable randomness source §

When your system requires a random number (and it does very often), OpenBSD only provides one API to get a random number and they are really random and can't be exhausted. A good random number generator (RNG) is important for many cryptography requirements.

OpenBSD presentation about arc4random

2.8. Accurate documentation §

OpenBSD comes with a full documentation in its man pages. One should be able to fully configure their system using only the man pages. Man pages comes with CAVEATS or BUGS sections sometimes, it's important to take care about those sections. It is better to read the documentation and understand what has to be done in order to configure a system instead of following an outdated and anonymous text available on the Internet.

OpenBSD man pages online

EuroBSDcon 2018 about « Better documentation »

2.9. IPSec and Wireguard out of the box §

If you need to setup a VPN, you can use IPSec or Wireguard protocols only using the base system, no package required.

2.10. Memory safeties §

OpenBSD has many safeties in regards to memory allocation and will prevent use after free or unsafe memory usage very aggressively, this is often a source of crash for some software from packages because OpenBSD is very strict when you want to use the memory. This helps finding memory misuses and will kill software misbehaving.

2.11. Dedicated root account §

When you install the system, a root account is created and its password is asked, then you create a user that will be member of "wheel" group, allowing it to switch user to root with root's password. doas (OpenBSD base system equivalent of sudo) isn't configured by default. With the default installation, the root password is required to do any root action. I think a dedicated root account that can be logged in without use of doas/sudo is better than a misconfigured doas/sudo allowing every thing only if you know the user password.

2.12. Small network attack surface §

The only services that could be enabled at installation time listening on the network are OpenSSH (asked at install time with default = yes), dhclient (if you choose dhcp) and slaacd (if you use ipv6 in automatic configuration).

2.13. Encrypted swap §

By default the OpenBSD swap is encrypted, meaning if programs memory are sent to the swap nobody can recover it later.

2.14. SMT disabled §

Due to a heavy number of security breaches due to SMT (like hyperthreading), the default installation disables the logical cores to prevent any data leak.

Meltdown: one of the first security issue related to speculative execution in the CPU

2.15. Micro and Webcam disabled §

With the default installation, both microphone and webcam won't actually record anything except blank video/sound until you set a sysctl for this.

2.15.1. Maintainability, release often, update often §

The OpenBSD team publish a new release a new version every six months and only last two releases receives security updates. This allows to upgrade often but without pain, the upgrade process are small steps twice a year that help keep the whole system up to date. This avoids the fear of a huge upgrade and never doing it and I consider it a huge security bonus. Most OpenBSD around are running latest versions.

2.15.2. Signify chain of trust §

Installer, archives and packages are signed using signify public/private keys. OpenBSD installations comes with the release and release n+1 keys to check the packages authenticity. A key is used only six months and new keys are received in each new release allowing to build a chain of trust. Signify keys are very small and are published on many medias to double check when you need to bootstrap this chain of trust.

Signify at BSDCan 2015

2.16. Packages §

While most of the previous items were about the base system or the kernel, the packages also have a few tricks to offer.

2.16.1. Chroot by default when available §

Most daemons that are available offering a chroot feature will have it enabled by default. In some circumstances like for Nginx web server, the software is patched by the OpenBSD team to enable chroot which is not an official feature.

2.16.2. Dedicated users for services §

Most packages that provide a server also create a new dedicated user for this exact service, allowing more privilege separation in case of security issue in one service.

2.16.3. Installing a service doesn't enable it §

When you install a service, it doesn't get enabled by default. You will have to configure the system to enable it at boot. There is a single /etc/rc.conf.local file that can be used to see what is enabled at boot, this can be manipulated using rcctl command. Forcing the user to enable services makes the system administrator fully aware of what is running on the system, which is good point for security.

rcctl man page

3. Conclusion §

Most of the previous "security features" should be considered good practices and not features. Many good practices such as the following could be easily implemented into most systems: Limiting users resources, reducing daemon privileges, memory usage strictness, providing a good documentation, start the least required services and provide the user a clean default installation.

There are also many other features that have been added and which I don't fully understand, and that I prefer letting the reader take notice.

« Mitigations and other real security features » by Theo De Raadt

OpenBSD innovations

OpenBSD events, often including slides or videos

Firejail on Linux to sandbox all the things

Written by Solène, on 14 February 2021.
Tags: #linux #security #sandbox

Comments on Fediverse/Mastodon

1. Introduction §

Firejail is a program that can prepare sandboxes to run other programs. This is an efficient way to keep a software isolated from the rest of the system without need of changing its source code, it works for network, graphical or daemons programs.

You may want to sandbox programs you run in order to protect your system for any issue that could happen within the program (security breach, code mistake, unknown errors), like Steam once had a "rm -fr /" issue, using a sandbox that would have partially saved a part of the user directory. Web browsers are major tools nowadays and yet they have access to the whole system and have many security issues discovered and exploited in the wild, running it in a sandbox can reduce the data a hacker could exfiltrate from the computer. Of course, sandboxing comes with an usability tradeoff because if you only allow access to the ~/Downloads/ directory, you need to put files in this directory if you want to upload them, and you can only download files into this directory and then move them later where you really want to keep your files.

2. Installation §

On most Linux systems you will find a Firejail package that you can install. If your distribution doesn't provide a Firejail package, it seems the installing from sources process is quite easy, and as the project is written in C with limited dependencies it may be easy to get the build process done.

There are no service to enable and no kernel parameters to add. Apparmor or SELinux features in kernel can be used to integrates into Firejail profiles if you want to.

3. Usage §

3.1. Start a program §

The simplest usage is to run a command by adding Firejail before the command name.

$ Firejail firefox

Firejail has a neat feature to allow starting software by their name without calling Firejail explicitly, if you create a symbolic link in your $PATH using a program name but targeting Firejail, when you call that name Firejail will automatically now what you want to start. The following example will run firefox when you call the symbolic link.

export PATH=~/bin/:$PATH
$ ln -s /usr/bin/firejail ~/bin/firefox
$ firefox

3.3. Listing sandboxes §

There is a Firejail --list command that will tell you about all sandboxes running and what are their parameters. As a first column the identifier is available for more Firejail features.

$ firejail --list
6108:solene::/usr/bin/firejail /usr/bin/firefox 

3.4. Limit bandwidth per program §

Firejail also has a neat feature that allows to limit the bandwidth available only for one sandbox environment. Reusing previous list output, I will reduce firefox bandwidth, the number are in kB/s.

$ firejail --bandwidth=6108 set wlan0 1000 40

You can find more information about this feature in the "TRAFFIC SHAPING" section of the Firejail man page.

3.5. Restrict network access §

If for some reason you want to start a program with absolutely no network access, you can run a program and deny it any network.

$ firejail --net=none libreoffice

4. Conclusion §

Firejail is a neat way to start software into sandboxes without requiring any particular setup. It may be more limited and maybe less reliable than OpenBSD programs who received unveil() features but it's a nice trade off between safety and required work within source code (literally none). It is a very interesting project that proves to work easily on any Linux system, with a simple C source code with little dependencies. I am not really familiar with Linux kernel and its features but Firejail seems to use seccomp-bpf and namespace, I guess they are complicated to use but powerful and Firejail comes here as a wrapper to automate all of this.

Firejail has been proven to be USABLE and RELIABLE for me while my attempts at sandboxing Firefox with AppArmor were tedious and not optimal. I really recommend it.

5. More resources §

Official project website with releases and security information

Firejail sources and documentation

Community profiles 1

Community profiles 2

Bandwidth limiting on OpenBSD 6.8

Written by Solène, on 07 February 2021.
Tags: #openbsd #unix #network

Comments on Fediverse/Mastodon

This is a February 2021 update of a text originally published in April 2017.

0.1. Introduction §

I will explain how to limit bandwidth on OpenBSD using its firewall PF (Packet Filter) queuing capability. It is a very powerful feature but it may be hard to understand at first. What is very important to understand is that it's technically not possible to limit the bandwidth of the whole system, because once data is getting on your network interface, it's already there and got by your router, what is possible is to limit the upload rate to cap the download rate.

OpenBSD pf.conf man page about queuing

0.2. Prerequisites §

My home internet access allows me to download at 1600 kB/s and upload at 95 kB/s. An easy way to limit bandwidth is to calculate a percent of your upload, that should apply that ratio to your download speed as well (this may not be very precise and may require tweaks).

PF syntax requires bandwidth to be defined as kilo-bits (kb) and not kilo-bytes (kB), multiplying by 8 allow to switch from kB to kb.

0.3. Configuration §

Edit the file /etc/pf.conf as root and add the following before any pass/match/drop rules, in the example my main interface is em0.

# we define a main queue (requirement)
queue main on em0 bandwidth 1G

# set a queue for everything
queue normal parent main bandwidth 200K max 200K default

And reload with pfctl -f /etc/pf.conf as root. You can monitor the queue working with systat queue

QUEUE        BW/FL SCH      PKTS    BYTES   DROP_P   DROP_B QLEN
main on em0  1000M fifo        0        0        0        0    0
 normal      1000M fifo   535424 36032467        0        0   60

0.4. More control (per user / protocol) §

This is only a global queuing rule that will apply to everything on the system. This can be greatly extended for specific need. For example, I use the program "oasis" which is a daemon for a peer to peer social network, sometimes it has upload burst because someone is syncing against my computer, I use the following rule to limit the upload bandwidth of this user.

# within the queue rules
queue oasis parent main bandwidth 150K max 150K

# in your match rules
match on egress proto tcp from any to any user oasis set queue oasis

Instead of a user, the rule could match a "to" address, I used to have such rules when I wanted to limit my upload bandwidth for uploading videos through peertube web interface.

How to set a system wide bandwidth limit on Linux systems

Written by Solène, on 06 February 2021.
Tags: #linux #bandwidth

Comments on Fediverse/Mastodon

In these times of remote work / home office, you may have a limited bandwidth shared with other people/device. All software doesn't provide a way to limit bandwidth usage (package manager, Youtube videos player etc...).

Fortunately, Linux has a very nice program very easy to use to limit your bandwidth in one command. This program is « Wondershaper » and is using the Linux QoS framework that is usually manipulated with "tc", but it makes it VERY easy to set limits.

What are QoS, TC and Filters on Linux

On most distributions, wondershaper will be available as a package with its own name. I found a few distributions that didn't provide it (NixOS at least), and some are providing various wondershaper versions.

To know if you have the newer version, a "wondershaper --help" may provide information about "-d" and "-u" flags, the older version doesn't have this.

Wondershaper requires the download and upload bandwidths to be set in kb/s (kilo bits per second, not kilo bytes). I personally only know my bandwidth in kB/s which is a 1/8 of its kb/s equivalent. My home connection is 1600 kB/s max in download and 95 kB/s max in upload, I can use wondershaper to limit to 1000 / 50 so it won't affect much my other devices on my network.

# my network device is enp3s0
# new wondershaper
sudo wondershaper -a enp3s0 -d $(( 1000 * 8 )) -u $(( 50 * 8 ))

# old wondershaper
sudo wondershaper enp3s0 $(( 1000 * 8 )) $(( 50 * 8 ))

I use a multiplication to convert from kB/s to kb/s and still keep the command understandable to me. Once a limit is set, wondershaper can be used to clear the limit to get full bandwidth available again.

# new wondershaper
sudo wondershaper -c -a enp3s0

# old wondershaper
sudo wondershaper clear enp3s0

There are so many programs that doesn't allow to limit download/upload speeds, wondershaper effectiveness and ease of use are a blessing.

Filtering TCP connections by operating system on OpenBSD

Written by Solène, on 06 February 2021.
Tags: #openbsd #security

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1. Introduction §

In this text I will explain how to filter TCP connections by operating system using OpenBSD Packet filter.

OpenBSD pf.conf man page about OS Fingerprinting

2. Explanations §

Every operating system has its own way to construct some SYN packets, this is called Fingerprinting because it permits to identify which OS sent which packet. This must be clear it's not a perfect filter and may be easily get bypassed if you want to.

Because if some packets required to identify the operating system, only TCP connections can be filtered by OS. The OS list and SYN values can be found in the file /etc/pf.os.

3. How to setup §

The keyword "os $value" must be used within the "from $address" keyword. I use it to restrict the ssh connection to my server only to OpenBSD systems (in addition to key authentication).

# only allow OpenBSD hosts to connect
pass in on egress inet proto tcp from any os OpenBSD to (egress) port 22

# allow connections from $home IP whatever the OS is
pass in on egress inet proto tcp from $home to (egress) port 22

This can be a very good way to stop unwanted traffic spamming logs but should be used with cautiousness because you may incidentally block legitimate traffic.

Using pkgsrc on OpenBSD

Written by Solène, on 06 February 2021.
Tags: #openbsd #pkgsrc

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This quick article will explain how to install pkgsrc packages on an OpenBSD installation. This is something regulary asked on #openbsd freenode irc channel. I am not convinced by the relevant use of pkgsrc under OpenBSD but why not :)

I will cover an unprivileged installation that doesn't require root. I will use packages from 2020Q4 release, I may not update regularly this text so you will have to adapt to your current year.

$ cd ~/
$ ftp https://cdn.NetBSD.org/pub/pkgsrc/pkgsrc-2020Q4/pkgsrc.tar.gz
$ tar -xzf pkgsrc.tar.gz
$ cd pkgsrc/bootstrap
$ ./bootstrap --unprivileged

From now you must add the path ~/pkg/bin to your $PATH environment variable. The pkgsrc tree is in ~/pkgsrc/ and all the relevant files for it to work are in ~/pkg/.

You can install programs by searching directories of software you want in ~/pkgsrc/ and run "bmake install", for example in ~/pkgsrc/chat/irssi/ to install irssi irc client.

I'm not sure X11 software compiles well, I got issues compiling dbus as a dependency of x11/xterm and I got compilation errors, maybe clashing with Xenocara from base system... I don't really want to investigate more about this though.

Enable multi-factor authentication on OpenBSD

Written by Solène, on 06 February 2021.
Tags: #openbsd #security

Comments on Fediverse/Mastodon

1. Introduction §

In this article I will explain how to add a bit more security to your OpenBSD system by adding a requirement for user logging into the system, locally or by ssh. I will explain how to setup 2 factor authentication (2FA) using TOTP on OpenBSD

What is TOTP (Time-based One time Password)

When do you want or need this? It adds a burden in term of usability, in addition to your password you will require a device that will be pre-configured to generate the one time passwords, if you don't have it you won't be able to login (that's the whole point). Let's say you activated 2FA for ssh connection on an important server, if you get your private ssh key stolen (and without password, bouh!), the hacker will not be able to connect to the SSH server without having access to your TOTP generator.

2. TOTP software §

Here is a quick list of TOTP software

- command line: oathtool from package oath-toolkit

- GUI and multiplatform: KeepassXC

- Android: FreeOTP+, andOTP, OneTimePass etc.. (watched on F-droid)

3. Setup §

A package is required in order to provide the various programs required. The package comes with a README file available at /usr/local/share/doc/pkg-readmes/login_oath with many explanations about how to use it. I will take lot of information from there for the local login setup.

# pkg_add login_oath

You will have to add a new login class, depending on what of the kind of authentication you want. You can either provide password OR TOTP, or set password AND TOTP (in the form of TOTP_CODE/password as the password to type). From the README file, add what you want to use:

# totp OR password
totp:\
        :auth=-totp,passwd:\
        :tc=default:

# totp AND password
totppw:\
        :auth=-totp-and-pwd:\
        :tc=default:

If you have a /etc/login.conf.db file, you have to run cap_mkdb on /etc/login.conf to update the file, most people don't need this, it only helps a bit in regards to performance when you have many many rules in /etc/login.conf.

4. Local login §

Local login means logging on a TTY or in your X session or anything requiring your system password. You can then modify the users you want to use TOTP by adding them to the according login class with this command.

# usermod -L totp some_user

In the user directory, you have to generate a key and give it the correct permissions.

$ openssl rand -hex 20 > ~/.totp-key
$ chmod 400 .totp-key

The .totp-key contains the secret that will be used by the TOTP generator, but most generator will only accept it in encoded as base32. You can use the following python3 command to convert the secret into base32.

python3 -c "import base64; print(base64.b32encode(bytes.fromhex('YOUR SECRET HERE')).decode('utf-8'))"

5. SSH login §

It is possible to require your users to use TOTP or a public key + TOTP. When your refer to "password" in ssh, this will be the same password as for login, so it can be the plain password for regular user, the TOTP code for users in totp class, and TOTP/password for users in totppw.

This allow fine grained tuning for login options. The password requirement in SSH can be enabled per user or globally by modifying the file /etc/ssh/sshd_config.

sshd_config man page about AuthenticationMethods

# enable for everyone
AuthenticationMethods publickey,password

# for one user
Match User solene
	AuthenticationMethods publickey,password

Let's say you enabled totppw class for your user and you use "publickey,password" in the AuthenticationMethods in ssh. You will require your ssh private key AND your password AND your TOTP generator.

Without doing any TOTP, by using this setting in SSH, you can require users to use their key and their system password in order to login, TOTP will only add more strength to the requirements to connect, but also more complexity for people who may not be comfortable with such security levels.

6. Conclusion §

In this text we have seen how to enable 2FA for your local login and for login over ssh. Be careful to not lock you out of your system by losing the 2FA generator.

NixOS review: pros and cons

Written by Solène, on 22 January 2021.
Tags: #nixos #linux

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Hello, in this article I would like to share my thoughts about the NixOS Linux distribution. I've been using it daily for more than six months as my main workstation at work and on some computer at home too. I also made modest contributions to the git repository.

NixOS official website

0.1. Introduction §

NixOS is a Linux distribution built around Nix tool. I'll try to explain quickly what Nix is but if you want more accurate explanations I recommend visiting the project website. Nix is the package manager of the system, Nix could be used on any Linux distribution on top of the distribution package manager. NixOS is built from top to bottom from Nix.

This makes NixOS a system entirely different than what one can expect from a regular Linux/Unix system (with the exception of Guix sharing the same idea with a different implementation). NixOS system configuration is stateless, most of the system is in read-only and most of paths you know doesn't exist. The directory /bin/sh only contains "sh" which is a symlink.

The whole system configuration: fstab, packages, users, services, crontab, firewall... is configured from a global configuration file that defines the state of the system.

An example of my configuration file to enable graphical interface with Mate as a desktop and a french keyboard layout.

services.xserver.enable = true;
services.xserver.layout = "fr";
services.xserver.libinput.enable = true;
services.xserver.displayManager.lightdm.enable = true;
services.xserver.desktopManager.mate.enable = true;

I could add the following lines into the configuration to add auto login into my graphical session.

services.xserver.displayManager.autoLogin.enable = true;
services.xserver.displayManager.autoLogin.user = "solene";

0.2. Pros §

There are a lot of pros. The system is really easy to setup, installing a system (for a reinstall or replicate an installation) is very easy, you only need to get the configuration.nix file from the other/previous system. Everything is very fast to setup, it's often only a few lines to add to the configuration.

Every time the system is rebuilt from the configuration file, a new grub entry is made so at boot you can choose on which environment you want to boot. This make upgrades or tries very easy to rollback and safe.

Documentation! The NixOS documentation is very nice and is part of the code. There is a special man page "configuration.nix" in the system that contains all variables you can define, what values to expect, what is the default and what it's doing. You can literally search for "steam", "mediawiki" or "luks" to get information to configure your system.

All the documentation

Builds are reproducible, I don't consider it a huge advantage but it's nice to have it. This allow to challenge a package mirror by building packages locally and verifying they provide the exact same package on the mirror.

It has a lot of packages. I think the NixOS team is pretty happy to share their statistics because, if I got it right, Nixpkgs is the biggest and up to date repository alive.

Search for a package

0.3. Cons §

When you download a pre compiled Linux program that isn't statically built, it's a huge pain to make it work on NixOS. The binary will expect some paths to exist at usual places but they won't exist on NixOS. There are some tricks to get them work but it's not always easy. If the program you want isn't in the packages, it may not be easy to use it. Flatpak can help to get some programs if they are not in the packages though.

Running binaries

It takes disk space, some libraries can exist at the same time with small compilation differences. A program can exist with different version at the same time because of previous builds still available for boot in grub, if you forget to clean them it takes a lot of memory.

The whole system (especially for graphical environments) may not feel as polished as more mainstream distributions putting a lot of efforts into branding and customization. NixOS will only install everything and you will have a quite raw environment that you will have to configure. It's not a real cons but in comparison to other desktop oriented distributions, NixOS may not look as good out of the box.

0.4. Conclusion §

NixOS is an awesome piece of software. It works very well and I never had any reliability issue with it. Some services like xrdp are usually quite complex to setup but it worked out of the box here for me.

I see it as a huge Lego© box with which you can automate the building of the super system you want, given you have the schematics of its parts. Once you need a block you don't have in your recipes list, you will have a hard time.

I really classify it into its own category, in comparison to Linux/BSD distributions and Windows, there is the NixOS / Guix category with those stateless systems for which the configuration is their code.

Vger security analysis

Written by Solène, on 14 January 2021.
Tags: #vger #gemini #security

Comments on Fediverse/Mastodon

I would like to share about Vger internals in regards to how the security was thought to protect vger users and host systems.

Vger code repository

1. Thinking about security first §

I claim about security in Vger as its main feature, I even wrote Vger to have a secure gemini server that I can trust. Why so? It's written in C and I'm a beginner developer in this language, this looks like a scam.

I chose to follow the best practice I'm aware of from the very first line. My goal is to be sure Vger can't be used to exfiltrate data from the host on which it runs or to allow it to run arbirary command. While I may have missed corner case in which it could crash, I think a crash is the worse that can happen with Vger.

1.1. Smallest code possible §

Vger doesn't have to manage connections or TLS, this was a lot of code already removed by this design choice. There are better tools which are exactly made for this purpose, so it's time to reuse other people good work.

1.2. Inetd and user §

Vger is run by inetd daemon, allowing to choose the user running vger. Using a dedicated user is always a good idea to prevent any harm in case of issue, but it's really not sufficient to protect vger to behave badly.

Another kind of security benefit is that vger runtime isn't looping like a daemon awaiting new connections. Vger accept a request, read a file if exist and gives its result and terminates. This is less error prone because no variable can be reused or tricked after a loop that could leave the code in an inconsistent or vulnerable state.

1.3. Chroot §

A critical vger feature is the ability to chroot into a directory, meaning the directory is now seen as the root of the file system (/var/gemini would be seen as /) and prevent vger to escape it. In addition to the chroot feature, the feature allow vger to drop to an unprivileged user.

     /* 
      * use chroot() if a user is specified requires root user to be 
      * running the program to run chroot() and then drop privileges 
      */
     if (strlen(user) > 0) {

             /* is root? */
             if (getuid() != 0) {
                     syslog(LOG_DAEMON, "chroot requires program to be run as root");
                     errx(1, "chroot requires root user");
             }
             /* search user uid from name */
             if ((pw = getpwnam(user)) == NULL) {
                     syslog(LOG_DAEMON, "the user %s can't be found on the system", user);
                     err(1, "finding user");
             }
             /* chroot worked? */
             if (chroot(path) != 0) {
                     syslog(LOG_DAEMON, "the chroot_dir %s can't be used for chroot", path);
                     err(1, "chroot");
             }
             chrooted = 1;
             if (chdir("/") == -1) {
                     syslog(LOG_DAEMON, "failed to chdir(\"/\")");
                     err(1, "chdir");
             }
             /* drop privileges */
             if (setgroups(1, &pw->pw_gid) ||
                 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
                 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) {
                     syslog(LOG_DAEMON, "dropping privileges to user %s (uid=%i) failed",
                            user, pw->pw_uid);
                     err(1, "Can't drop privileges");
             }
     }

1.4. No use of third party libs §

Vger only requires standard C includes, this avoid leaving trust to dozens of developers using fragile or barely tested code.

1.5. OpenBSD specific code §

In addition to all the previous security practices, OpenBSD is offering a few functions to help restricting a lot what Vger can do.

The first function is pledge, allowing to restrict the system calls that can happen within the code itself. The current syscalls allowed in vger are related to the categories "rpath" and "stdio", basically standard input/output and reading files/directories only. This mean after pledge() is called, if any syscall not in those two categories is used, vger will be killed and a pledge error will be reported in the logs.

The second function is unveil, which will basically restrict access to the filesystem to anything but what you list, with the permission. Currently, vger only allows file access in read-only mode in the base directory used to serve files.

Here is an extract of the code relative to the OpenBSD specific code. With unveil available everywhere chroot wouldn't be required.

 #ifdef __OpenBSD__
         /* 
          * prevent access to files other than the one in path 
          */
         if (chrooted) {
                 eunveil("/", "r");
         } else {
                 eunveil(path, "r");
         }
         /* 
          * prevent system calls other parsing queryfor fread file and 
          * write to stdio 
          */
         if (pledge("stdio rpath", NULL) == -1) {
                 syslog(LOG_DAEMON, "pledge call failed");
                 err(1, "pledge");
         }
 #endif

2. The least code before dropping privileges §

I made my best to use the least code possible before reducing Vger capabilities. Only the code managing the parameters is done before activating chroot and/or unveil/pledge.

int
main(int argc, char **argv)
{
     char            request  [GEMINI_REQUEST_MAX] = {'\0'};
     char            hostname [GEMINI_REQUEST_MAX] = {'\0'};
     char            uri      [PATH_MAX]           = {'\0'};
     char            user     [_SC_LOGIN_NAME_MAX] = "";
     int             virtualhost = 0;
     int             option = 0;
     char           *pos = NULL;

     while ((option = getopt(argc, argv, ":d:l:m:u:vi")) != -1) {
             switch (option) {
             case 'd':
                     estrlcpy(chroot_dir, optarg, sizeof(chroot_dir));
                     break;
             case 'l':
                     estrlcpy(lang, "lang=", sizeof(lang));
                     estrlcat(lang, optarg, sizeof(lang));
                     break;
             case 'm':
                     estrlcpy(default_mime, optarg, sizeof(default_mime));
                     break;
             case 'u':
                     estrlcpy(user, optarg, sizeof(user));
                     break;
             case 'v':
                     virtualhost = 1;
                     break;
             case 'i':
                     doautoidx = 1;
                     break;
             }
     }

     /* 
      * do chroot if a user is supplied run pledge/unveil if OpenBSD 
      */
     drop_privileges(user, chroot_dir); 

3. The Unix way §

Unix is made of small component that can work together as small bricks to build something more complex. Vger is based on this idea by delegating the listening daemon handling incoming requests to another software (let's say relayd or haproxy). And then, what's left from the gemini specs once you delegate TLS is to take account of a request and return some content, which is well suited for a program accepting a request on its standard input and giving the result on standard ouput. Inetd is a key here to make such a program compatible with a daemon like relayd or haproxy. When a connection is made into the TLS listening daemon, a local port will trigger inetd that will run the command, passing the network content to the binary into its stdin.

4. Fine grained CGI §

CGI support was added in order to allow Vger to make dynamic content instead of serving only static files. It has a fine grained control, you can allow only one file to be executable as a CGI or a whole directory of files. When serving a CGI, vger forks, a pipe is opened between the two processes and a process is using execlp to run the cgi and transmit its output to vger.

5. Using tests §

From the beginning, I wrote a set of tests to be sure that once a kind of request or a use case work I can easily check I won't break it. This isn't about security but about reliability. When I push a new version on the git repository, I am absolutely confident it will work for the users. It was also an invaluable help for writing Vger.

As vger is a simple binary that accept data in stdin and output data on stdout, it is simple to write tests like this. The following example will run vger with a request, as the content is local and within the git repository, the output is predictable and known.

printf "gemini://host.name/autoidx/\r\n" | vger -d var/gemini/

From here, it's possible to build an automatic test by checking the checksum of the output to the checksum of the known correct output. Of course, when you make a new use case, this requires manually generating the checksum to use it as a comparison later.

OUT=$(printf "gemini://host.name/autoidx/\r\n" | ../vger -d var/gemini/ -i | md5)
if ! [ $OUT = "770a987b8f5cf7169e6bc3c6563e1570" ]
then
	echo "error"
	exit 1
fi

At this time, vger as 19 use case in its test suite.

By using the program entr and a Makefile to manage the build process, it was very easy to trigger the testing process while working on the source code, allowing me to check the test suite only by saving my current changes. Anytime a .c file is modified, entr will trigger a make test command that will be displayed in a dedicated terminal.

ls *.c | entr make test

Realtime integration tests? :)

6. Conclusion §

By using best practices, reducing the amount of code and using only system libraries, I am quite confident about Vger good security. The only real issue could be to have too many connections leading to a quite high load due to inetd spawning new processes and doing a denial of services. This could be avoided by throttling simultaneous connection in the TLS daemon.

If you want to contribute, please do, and if you find a security issue please contact me, I'll be glad to examine the issue.

Free time partitionning

Written by Solène, on 06 January 2021.
Tags: #life

Comments on Fediverse/Mastodon

Lately I wanted to change the way I use my free time. I define my free time as: not working, not sleeping, not eating. So, I estimate it to six hours a day in work day and fourteen hours in non worked day.

With the year 2020 being quite unusual, I was staying at home most of the time without seeing the time passing. At the end of the year, I started to mix the duration of weeks and months which disturbed me a lot.

For a a few weeks now, I started to change the way I spend my free time. I thought it was be nice to have a few separate activies in the same day to help me realizing how time is passing by.

1. Activity list §

Here is the way I chose to distribute my free time. It's not a strict approach, I measure nothing. But I try to keep a simple ratio of 3/6, 2/6 and 1/6.

1.1. Recreation: 3/6 §

I spend a lot of time in recreation time. A few activies I've put into recreation:

  • video games
  • movies
  • reading novels
  • sports

1.2. Creativity: 2/6 §

Those activies requires creativy, work and knowledge:

  • writing code
  • reading technical books
  • playing music
  • creating content (texts, video, audio etc..)

1.3. Chores: 1/6 §

Yes, obviously this has to be done on free time... And it's always better to do it a bit everyday than accumulating it until you are forced to proceed.

2. Conclusion §

I only started for a few weeks now but I really enjoy doing it. As I said previously, it's not something I stricly apply, but more a general way to spend my time and not stick for six hours writing code in a row from after work to going to sleep. I really feel my life is better balanced now and I feel some accomplishments for the few activies done every day.

3. Questions / Answers §

Some asked asked me if I was planning in advance how I spend my time.

The answer is no. I don't plan anything but when I tend to lose focus on what I'm doing (and this happen often), I think about this time repartition method and then I think it may be time to jump on another activity and I pick something in another category. Now I think about it, that was very often that I was doing something because I was bored and lacking idea of activities to occupy myself, with this current list I no longer have this issue.

Toward a simpler lifestyle

Written by Solène, on 04 January 2021.
Tags: #life

Comments on Fediverse/Mastodon

I don't often give my own opinion on this blog but I really feel it is important here.

The matter is about ecology, fair money distribution and civilization. I feel I need to share a bit about my lifestyle, in hope it will have a positive impact on some of my readers. I really think one person can make a change. I changed myself, only by spending a few moments with a member of my family a few years ago. That person never tried to convince me of anything, they only lived by their own standard without never offending me, it was simple things, nothing that would make that person a paria in our society. But I got curious about the reasons and I figurated it myself way later, now I understand why.

My philisophy is simple. In a life in modern civilization where everything is going fast, everyone cares about opinions other have about them and ultra communication, step back.

Here are the various statement I am following, this is something I self defined, it's not absolute rules.

  • Be yourself and be prepare to assume who you are. If you don't have the latest gadget you are not "has been", if you don't live in a giant house, you didn't fail your career, if you don't have a top notch shiny car nobody should ever care.
  • Reuse what you have. It's not because a cloth has a little scratch that you can't reuse it. It's not because an electronic device is old that you should replace it.
  • Opensource is a great way to revive old computers
  • Reduce your food waste to 0 and eat less meat because to feed animals we eat this requires a huge food production, more than what we finally eat in the meat
  • Travel less, there are a lot to see around where I live than at the other side of the planet. Certainly not go on vacation far away from home only to enjoy a beach under the sun. This also mean no car if it can be avoided, and if I use a car, why not carpooling?
  • Avoid gadgets (electronic devices that bring nothing useful) at all cost. Buy good gears (kitchen tools, workshop tools, furnitures etc...) that can be repaired. If possible buy second hand. For non-essential gears, second hand is mandatory.
  • In winter, heat at 19°C maximum with warm clothes while at home.
  • In summer, no A/C but use of extern isolation and vines along the home to help cooling down. And fans + water while wearing lights clothes to keep cool.

While some people are looking for more and more, I do seek for less. There are not enough for everyone on the planet, so it's important to make sacrifices.

Of course, it is how I am and I don't expect anyone to apply this, that would be insane :)

Be safe and enjoy this new year! <3

Lowtech Magazine, articles about doing things using simple technology

[FR] Pourquoi j'utilise OpenBSD

Written by Solène, on 04 January 2021.
Tags: #openbsd #francais

Comments on Fediverse/Mastodon

Dans ce billet je vais vous livrer mon ressenti sur ce que j'aime dans OpenBSD.

0.0.1. Respect de la vie privée §

Il n'y a aucune télémétrie dans OpenBSD, je n'ai pas à m'inquiéter pour le respect de ma vie privée. Pour rappel, la télémétrie est un mécanisme qui consiste à remonter des informations de l'utilisateur afin d'analyser l'utilisation du produit.

De plus, le défaut du système a été de désactiver entièrement le micro, à moins d'une intervention avec le compte root, le microphone enregistre du silence (ce qui permet de ne pas le bloquer quant à des droits d'utilisation). A venir dans 6.9, la caméra suit le même chemin et sera désactivée par défaut. Il s'agit pour moi d'un signal fort quant à la nécessité de protéger l'utilisateur.

0.0.2. Navigateurs web sécurisés §

Avec l'ajout des fonctionnalités de sécurité (pledge et surtout unveil) dans les sources de Firefox et Chromium, je suis plus sereine quant à leur utilisation au quotidien. À l'heure actuelle, l'utilisation d'un navigateur web est quasiment incontournable, mais ils sont à la fois devenus extrêmement complexes et mal maîtrisés. L'exécution de code côté client via Javascript qui a de plus en plus de possibilité, de performances et de nécessités, ajouter un peu de sécurité dans l'équation était nécessaire. Bien que ces ajouts soient parfois un peu dérangeants à l'utilisation, je suis vraiment heureuse de pouvoir en bénéficier.

Avec ces sécurités ajoutés (par défaut), les navigateurs cités précédemment ne peuvent pas parcourir les répertoires en dehors de ce qui leur est nécessaire à leur bon fonctionnement plus les dossiers ~/Téléchargements/ et /tmp/. Ainsi, des emplacements comme ~/Documents ou ~/.gnupg sont totalement inaccessibles ce qui limite grandement les risques d'exfiltration de données par le navigateur.

On pourrait refaire grossièrement la même fonctionnalité sous Linux en utilisant AppArmor mais l'intégration est extrêmement compliquée (là où c'est par défaut sur OpenBSD) et un peu moins efficace, il est plus facile d'agir au bon moment depuis le code plutôt qu'en encapsulant le programme entier d'un groupe de règles.

0.0.3. Pare-feu PF §

Avec PF, il est très simple de vérifier le fichier de configuration pour comprendre les règles en place sur le serveur ou un ordinateur de bureau. La centralisation des règles dans un fichier et le système de macros permet d'écrire des règles simples et lisibles.

J'utilise énormément la fonctionnalité de gestion de bande passante pour limiter le débit de certaines applications qui n'offrent pas ce réglage. C'est très important pour moi n'étant pas la seule utilisatrice du réseau et ayant une connexion assez lente.

Sous Linux, il est possible d'utiliser les programmes trickle ou wondershaper pour mettre en place des limitations de bande passante, par contre, iptables est un cauchemar à utiliser en tant que firewall!

0.0.4. C'est stable §

A part à l'utilisation sur du matériel peu répandu, OpenBSD est très stable et fiable. Je peux facilement atteindre deux semaines d'uptime sur mon pc de bureau avec plusieurs mises en veille par jour. Mes serveurs OpenBSD tournent 24/24 sans problème depuis des années.

Je dépasse rarement deux semaines puisque je dois mettre à jour le système de temps en temps pour continuer les développements sur OpenBSD :)

0.0.5. Peu de maintenance §

Garder à jour un système OpenBSD est très simple. Je lance les commandes syspatch et pkg_add -u tous les jours pour garder mes serveurs à jour. Une mise à jour tous les six mois est nécessaire pour monter en version mais à part quelques instructions spécifiques qui peuvent parfois arriver, une mise à jour ressemble à ça :

# sysupgrade
[..attendre un peu..]
# pkg_add -u
# reboot

0.0.6. Documentation de qualité §

Installer OpenBSD avec un chiffrement complet du disque est très facile (il faudra que j'écrive un billet sur l'importance de chiffrer ses disques et téléphones).

La documentation officielle expliquant l'installation d'un routeur avec NAT est parfaitement expliquée pas à pas, c'est une référence dès qu'il s'agit d'installer un routeur.

Tous les binaires du système de base (ça ne compte pas les packages) ont une documentation, ainsi que leurs fichiers de configuration.

Le site internet, la FAQ officielle et les pages de man sont les seules ressources nécessaires pour s'en sortir. Elles représentent un gros morceau, il n'est pas toujours facile de s'y retrouve mais tout y est.

Si je devais me débrouiller pendant un moment sans internet, je préférerais largement être sur un système OpenBSD. La documentation des pages de man suffit en général à s'en sortir.

Imaginez mettre en place un routeur qui fait du trafic shaping sous OpenBSD ou Linux sans l'aide de documents extérieurs au système. Personnellement je choisis OpenBSD à 100% pour ça :)

0.0.7. Facilité de contribution §

J'adore vraiment la façon dont OpenBSD gère les contributions. Je récupère les sources sur mon système et je procède aux modifications, je génère un fichier de diff (différence entre avant/après) et je l'envoie sur la liste de diffusion. Tout ça peut être fait en console avec des outils que je connais déjà (git/cvs) et des emails.

Parfois, les nouveaux contributeurs peuvent penser que les personnes qui répondent ne sont vraiment pas sympa. **Ce n'est pas vrai**. Si vous envoyez un diff et que vous recevez une critique, cela signifie déjà qu'on vous accorde du temps pour vous expliquer ce qui peut être amélioré. Je peux comprendre que cela puisse paraître rude pour certaines personnes, mais ce n'est pas ça du tout.

Cette année, j'ai fait quelques modestes contributions aux projets OpenIndiana et NixOS, c'était l'occasion de découvrir comment ces projets gèrent les contributions. Les deux utilisent github et la manière de faire est très intéressante, mais la comprendre demande beaucoup de travail car c'est relativement compliqué.

Site officiel d'OpenIndiana

Site officiel de NixOS

La méthode de contribution nécessite un compte sur Github, de faire un fork du projet, cloner le fork en local, créer une branche, faire les modifications en local, envoyer le fork sur son compte github et utiliser l'interface web de github pour faire un "pull request". Ça c'est la version courte. Sur NixOS, ma première tentative de faire un pull request s'est terminée par une demande contenant six mois de commits en plus de mon petit changement. Avec une bonne documentation et de l'entrainement c'est tout à fait surmontable. Cette méthode de travail présente certains avantages comme le suivi des contributeurs, l'intégration continue ou la facilité de critique de code, mais c'est rebutoire au possible pour les nouveaux.

0.0.8. Packages top qualité §

Mon opinion est sûrement biaisée ici (bien plus que pour les éléments précédents) mais je pense sincèrement que les packages d'OpenBSD sont de très bonne qualité. La plupart d'entre eux fonctionnent "out of the box" avec des paramètres par défaut corrects.

Les packages qui nécessitent des instructions particulières sont fournis avec un fichier "readme" expliquant ce qui est nécessaire, par exemple créer certains répertoires avec des droits particuliers ou comment mettre à jour depuis une version précédente.

Même si par manque de contributeurs et de temps (en plus de certains programmes utilisant beaucoup de linuxismes pour être faciles à porter), la plupart des programmes libres majeurs sont disponibles et fonctionnent très bien.

Je profite de l'occasion de ce billet pour critiquer une tendance au sein du monde Open Source.

  • les programmes distribués avec flatpak / docker / snap fonctionnent très bien sur Linux mais sont hostiles envers les autres systèmes. Ils utilisent souvent des fonctionnalités spécifiques à Linux et les méthodes de compilation sont tournées vers Linux. Cela complique grandement le portage de ces applications vers d'autres systèmes.
  • les programmes avec nodeJS: ils nécessitent parfois des centaines voir des milliers des libs et certaines sont mêmes un peu bancales. C'est vraiment compliqué de faire fonctionner ces programmes sur OpenBSD. Certaines libs vont même jusqu'à embarquer du code rust ou à télécharger un binaire statique sur un serveur distant sans solution de compilation si nécessaire ou sans regardant si ce binaire est disponible dans $PATH. On y trouve des aberrations incroyables.
  • les programmes nécessitant git pour compiler: le système de compilation dans les ports d'OpenBSD fait de son mieux pour faire au plus propre. L'utilisateur dédié à la création des packages n'a pas du tout accès à internet (bloqué par le pare-feu avec une règle par défaut) et ne pourra pas exécuter de commande git pour récupérer du code. Il n'y a aucune raison pour que la compilation d'un programme nécessite de télécharger du code au milieu de l'étape de compilation!

Évidemment je comprends que ces trois points ci-dessus existent car cela facilite la vie des développeurs, mais si vous écrivez un programme et que vous le publiez, ce serait très sympa de penser aux systèmes non-linux. N'hésite pas à demander sur les réseaux sociaux si quelqu'un veut tester votre code sur un autre système que Linux. On adore les développeurs "BSD friendly" qui acceptent nos patches pour améliorer le support OpenBSD.

0.0.9. Ce que j'aimerais voir évoluer §

Il y a certaines choses où j'aimerais voir OpenBSD s'améliorer. Cette liste est personnelle et reflète pas l'opinion des membres du projet OpenBSD.

  • Meilleur support ARM
  • Débit du Wifi
  • Meilleures performances (mais ça s'améliore un peu à chaque version)
  • Améliorations de FFS (lors de crashs j'ai parfois des fichiers dans lost+found)
  • Un pkg_add -u plus rapide
  • Support du décodage vidéo matériel
  • Meilleur support de FUSE avec une possibilité de monter des systèmes CIFS/samba
  • Plus de contributeurs

Je suis consciente de tout le travail nécessaire ici, et ce n'est certainement pas moi qui vais y faire quelque chose. J'aimerais que cela s'améliore sans toutefois me plaindre de la situation actuelle :)

Malheureusement, tout le monde sait qu'OpenBSD évolue par un travail acharné et pas en envoyant une liste de souhaits aux développeurs :)

Quand on pense à ce qu'arrive à faire une petite équipe (environ 150 développeurs impliqués sur les dernières versions) en comparaison d'autres systèmes majeurs, je pense qu'on est assez efficace!

[FR] Méthodes de publication de mon blog sur plusieurs médias

Written by Solène, on 03 January 2021.
Tags: #life #blog #francais

Comments on Fediverse/Mastodon

On me pose souvent la question sur la façon dont je publie mon blog, comment j'écris mes textes et comment ils sont publiés sur trois médias différents. Cet article est l'occasion pour moi de répondre à ces questions.

Pour mes publications j'utilise le générateur de site statique "cl-yag" que j'ai développé. Son principal travail est de générer les fichiers d'index d'accueil et de chaque tags pour chacun des médias de diffusion, HTML pour http, gophermap pour gopher et gemtext pour gemini. Après la génération des indexs, pour chaque article publié en HTML, un convertisseur va être appelé pour transformer le fichier d'origine en HTML afin de permettre sa consultation avec un navigateur internet. Pour gemini et gopher, l'article source est simplement copié avec quelques méta-données ajoutées en haut du fichier comme le titre, la date, l'auteur et les mots-clés.

Publier sur ces trois format en même temps avec un seul fichier source est un défi qui requiert malheureusement de faire des sacrifices sur le rendu si on ne veut pas écrire trois versions du même texte. Pour gopher, j'ai choisi de distribuer les textes tel quel, en tant que fichier texte, le contenu peut être du markdown, org-mode, mandoc ou autre mais gopher ne permet pas de le déterminer. Pour gémini, les textes sont distribués comme .gmi qui correspondent au type gemtext même si les anciennes publications sont du markdown pour le contenu. Pour le http, c'est simplement du HTML obtenu via une commande en fonction du type de données en entrée.

J'ai récemment décidé d'utiliser le format gemtext par défaut plutôt que le markdown pour écrire mes articles. Il a certes moins de possibilités que le markdown, mais le rendu ne contient aucune ambiguïté, tandis que le rendu d'un markdown peut varier selon l'implémentation et le type de markdown (tableaux, pas tableaux ? Syntaxe pour les images ? etc...)

Lors de l'exécution du générateur de site, tous les indexs sont régénérées, pour les fichiers publiés, la date de modification de celui-ci est comparée au fichier source, si la source est plus récente alors le fichier publié est généré à nouveau car il y a eu un changement. Cela permet de gagner énormément de temps puisque mon site atteint bientôt les 200 articles et copier 200 fichiers pour gopher, 200 pour gemini et lancer 200 programmes de conversion pour le HTML rendrait la génération extrêmement longue.

Après la génération de tous les fichiers, la commande rsync est utilisée pour mettre à jour les dossiers de sortie pour chaque protocole vers le serveur correspondant. J'utilise un serveur pour le http, deux serveurs pour gopher (le principal n'était pas spécialement stable à l'époque), un serveur pour gemini.

J'ai ajouté un système d'annonce sur Mastodon en appelant le programme local "toot" configuré sur un compte dédié. Ces changements n'ont pas été déployé dans cl-yag car il s'agit de changements très spécifiques pour mon utilisation personnelle. Ce genre de modification me fait penser qu'un générateur de site statique peut être un outil très personnel que l'on configure vraiment pour un besoin hyper spécifique et qu'il peut être difficile pour quelqu'un d'autre de s'en servir. J'avais décidé de le publier à l'époque, je ne sais pas si quelqu'un l'utilise activement, mais au moins le code est là pour les plus téméraires qui voudraient y jeter un oeil.

Mon générateur de blog peut supporter le mélange de différents types de fichiers sources pour être convertis en HTML. Cela me permet d'utiliser le type de formatage que je veux sans avoir à tout refaire.

Voici quelques commandes utilisées pour convertir les fichiers d'entrées (les articles bruts tels que je les écrits) en HTML. On constate que la conversion org-mode vers HTML n'est pas la plus simple. Le fichier de configuration de cl-yag est du code LISP chargé lors de l'exécution, je peux y mettre des commentaires mais aussi du code si je le souhaite, cela se révèle pratique parfois.

(converter :name :gemini    :extension ".gmi" :command "gmi2html/gmi2html data/%IN | tee %OUT")
(converter :name :markdown  :extension ".md"  :command "peg-markdown -t html -o %OUT data/%IN")
(converter :name :markdown2 :extension ".md"  :command "multimarkdown -t html -o %OUT data/%IN")
(converter :name :mmd       :extension ".mmd" :command "cat data/%IN | awk -f mmd | tee %OUT")
(converter :name :mandoc    :extension ".man"
           :command "cat data/%IN  | mandoc -T markdown | sed -e '1,2d' -e '$d' | multimarkdown -t html -o %OUT")
(converter :name :org-mode  :extension ".org"
	   :command (concatenate 'string
				 "emacs data/%IN --batch --eval '(with-temp-buffer (org-mode) "
				 "(insert-file \"%IN\") (org-html-export-as-html nil nil nil t)"
				 "(princ (buffer-string)))' --kill | tee %OUT"))

Quand je déclare un nouvel article dans le fichier de configuration qui détient les méta-données de toutes les publications, j'ai la possibilité de choisir le convertisseur HTML à utiliser si ce n'est pas celui par défaut.

;; utilisation du convertisseur par défaut
(post :title "Minimalistic markdown subset to html converter using awk"
      :id "minimal-markdown" :tag "unix awk" :date "20190826")

;; utilisation du convertisseur mmd, un script awk très simple que j'ai fait pour convertir quelques fonctionnalités de markdown en html
(post :title "Life with an offline laptop"
      :id "offline-laptop" :tag "openbsd life disconnected" :date "20190823" :converter :mmd)

Quelques statistiques concernant la syntaxe de mes différentes publications, via http vous ne voyez que le HTML, mais en gopher ou gemini vous verrez la source telle quelle.

  • markdown :: 183
  • gemini :: 12
  • mandoc :: 4
  • mmd :: 2
  • org-mode :: 1

My blog workflow

Written by Solène, on 03 January 2021.
Tags: #life #blog

Comments on Fediverse/Mastodon

I often have questions about how I write my articles, which format I use and how I publish on various medias. This article is the opportunity to highlight all the process.

So, I use my own static generator cl-yag which supports generating indexes for whole article lists but also for every tags in html, gophermap format and gemini gemtext. After the generation of indexes, for html every article will be converted into html by running a "converter" command. For gopher and gemini the original text is picked up, some metadata are added at the top of the file and that's all.

Publishing for all the three formats is complicated and sacrifices must be made if I want to avoid extra work (like writing a version for each). For gopher, I chose to distribute them as simple text file but it can be markdown, org-mode, mandoc or other formats, you can't know. For gemini, it will distribute gemtext format and for http it will be html.

Recently, I decided to switch to gemtext format instead of markdown as the main format for writing new texts, it has a bit less features than markdown, but markdown has some many implementations than the result can differ greatly from one renderer to another.

When I run the generator, all the indexes are regenerated, and destination file modification time are compared to the original file modification time, if the destination file (the gopher/html/gemini file that is published) is newer than the original file, no need to rewrite it, this saves a lot of time. After generation, the Makefile running the program will then run rsync to various servers to publish the new directories. One server has gopher and html, another server only gemini and another server has only gopher as a backup.

I added a Mastodon announcement calling a local script to publish links to new publications on Mastodon, this wasn't merged into cl-yag git repository because it's too custom code depending on local programs. I think a blog generator is as personal as the blog itself, I decided to publish its code at first but I am not sure it makes much sense because nobody may have the same mindset as mine to appropriate this tool, but at least it's available if someone wants to use it.

My blog software can support mixing input format so I am not tied to a specific format for all its life.

Here are the various commands used to convert a file from its original format to html. One can see that converting from org-mode to html in command line isn't an easy task. As my blog software is written in Common LISP, the configuration file is also a valid common lisp file, so I can write some code in it if required.

(converter :name :gemini    :extension ".gmi" :command "gmi2html/gmi2html data/%IN | tee %OUT")
(converter :name :markdown  :extension ".md"  :command "peg-markdown -t html -o %OUT data/%IN")
(converter :name :markdown2 :extension ".md"  :command "multimarkdown -t html -o %OUT data/%IN")
(converter :name :mmd       :extension ".mmd" :command "cat data/%IN | awk -f mmd | tee %OUT")
(converter :name :mandoc    :extension ".man"
           :command "cat data/%IN  | mandoc -T markdown | sed -e '1,2d' -e '$d' | multimarkdown -t html -o %OUT")
(converter :name :org-mode  :extension ".org"
	   :command (concatenate 'string
				 "emacs data/%IN --batch --eval '(with-temp-buffer (org-mode) "
				 "(insert-file \"%IN\") (org-html-export-as-html nil nil nil t)"
				 "(princ (buffer-string)))' --kill | tee %OUT"))

When I define a new article to generate from a main file holding the metadata, I can specify the converter if it's not the default one configured.

;; using default converter
(post :title "Minimalistic markdown subset to html converter using awk"
      :id "minimal-markdown" :tag "unix awk" :date "20190826")

;; using mmd converter, a simple markdown to html converter written in awk
(post :title "Life with an offline laptop"
      :id "offline-laptop" :tag "openbsd life disconnected" :date "20190823" :converter :mmd)

Some statistics about the various format used in my blog.

  • markdown :: 183
  • gemini :: 12
  • mandoc :: 4
  • mmd :: 2
  • org-mode :: 1

Port of the week: Lagrange

Written by Solène, on 02 January 2021.
Tags: #portoftheweek #gemini

Comments on Fediverse/Mastodon

Today's Port of the Week is about Lagrange, a gemini web browser.

Lagrange official website

Information about the Gemini protocol

Curated list of Gemini clients

Lagrange is the finest browser I ever used and it's still brand new. I imported it into OpenBSD and so it will be available starting from OpenBSD 6.9 releases.

Screenshot of the web browser in action with dark mode, it supports left and right side panels.
Screenshot of the web browser in action with dark mode, it supports left and right side panels.

Lagrange is fantastic in the way it helps the user with the content browsed.

  • Links already visited display the last visited date
  • Subscription on page without RSS is possible for pages respecting a specific format (most of gemini space does)
  • Easy management of client certificates, used for authentication
  • In-page image loading, video watching and sound playing
  • Gopher support
  • Table of content displayed generated from headings
  • Keyboard navigation
  • Very light (dependencies, memory footprint, cpu usage)
  • Smooth scrolling
  • Dark and light modes
  • Much more

If you are interested into Gemini, I highly recommend this piece of software as a browser.

In case you would like to host your own Gemini content without requiring infrastructure, some community servers are offering hosting through secure sftp transfers.

Si3t.ch community Gemini hosting

Un bon café !

Once you get into Gemini space, I recommend the following resources:

CAPCOM feed agregator, a great place to meet new authors

GUS: a search engine

Vger gemini server can now redirect

Written by Solène, on 02 January 2021.
Tags: #gemini

Comments on Fediverse/Mastodon

I added a new feature to Vger gemini server.

Vger git repository

The protocol supports status code including redirections, Vger had no way to know if a user wanted to redirect a page to another. The redirection litteraly means "You asked for this content but it is now at that place, load it from there".

To keep it with vger Unix way, a redirection is done using a symbolic link:

The following command would redirect requests from gemini://perso.pw/blog/index.gmi to gemini://perso.pw/capsule/index.gmi:

ln -s "gemini://perso.pw/capsule/index.gmi" blog/index.gmi

Unfortunately, this doesn't support globbing, in other words it is not possible to redirect everything from /blog/ to /capsule/ without creating a symlink for all previous resources to their new locations.

Host your Cryptpad web office suite with OpenBSD

Written by Solène, on 14 December 2020.
Tags: #web #openbsd

Comments on Fediverse/Mastodon

In this article I will explain how to deploy your own cryptpad instance with OpenBSD.

Cryptpad official website

Cryptpad is a web office suite featuring easy real time collaboration on documents. Cryptpad is written in JavaScript and the daemon acts as a web server.

1. Pre-requisites §

You need to install the packages git, node, automake and autoconfig to be able to fetch the sources and run the program.

# pkg_add node git autoconf--%2.69 automake--%1.16

Another web front-end software will be required to allow TLS connections and secure the network access to the Cryptpad instance. This can be relayd, haproxy, nginx or lighttpd. I'll cover the setup using httpd, and relayd. Note that Cryptpad developers will provide support only to Nginx users.

2. Installation §

I really recommend using dedicated users daemons. We will create a new user with the command:

# useradd -m _cryptpad

Then we will continue the software installation as the _cryptpad user.

# su -l _cryptpad

We will mainly follow the official instructions with some exceptions to adapt to OpenBSD:

Official installation guide

$ git clone https://github.com/xwiki-labs/cryptpad
$ cd cryptpad
$ env AUTOMAKE_VERSION=1.16 AUTOCONF_VERSION=2.69 CC=clang CXX=clang++ npm install
$ env AUTOMAKE_VERSION=1.16 AUTOCONF_VERSION=2.69 CC=clang CXX=clang++ npm install bower
$ node_modules/.bin/bower install
$ cp config/config.example.js config/config.js

3. Configuration §

There are a few variables important to customize:

  • "httpUnsafeOrigin" should be set to the public address on which cryptpad will be available. This will certainly be a HTTPS link with an hostname. I will use https://cryptpad.kongroo.eu
  • "httpSafeOrigin" should be set to a public address which is different than the previous one. Cryptpad requires two different addresses to work. I will use https://api.cryptpad.kongroo.eu
  • "adminEmail" must be set to a valid email used by the admin (certainly you)

4. Make a rc file to start the service §

We need to automatically start the service properly with the system.

Create the file /etc/rc.d/cryptpad

#!/bin/ksh

daemon="/usr/local/bin/node"
daemon_flags="server"
daemon_user="_cryptpad"
location="/home/_cryptpad/cryptpad"

. /etc/rc.d/rc.subr

rc_start() {
	${rcexec} "cd ${location}; ${daemon} ${daemon_flags}"
}

rc_bg=YES
rc_cmd $1

Enable the service and start it with rcctl

# rcctl enable cryptpad
# rcctl start cryptpad

5. Operating §

5.1. Make an admin account §

Register yourself on your Cryptpad instance then visit the *Settings* page of your profile: copy your public signing key.

Edit Cryptpad file config.js and search for the pattern "adminKeys", uncomment it by removing the "/* */" around and delete the example key and paste your key as follow:

adminKeys: [
    "[solene@cryptpad.kongroo.eu/YzfbEYwZq6Xhl7ET6AHD01w3QqOE7STYgGglgSTgWfk=]",
],

Restart Cryptpad, the user is now admin and has access to a new administration panel from the web application.

5.2. Backups §

In the cryptpad directory, you need to backup data and datastore directories.

6. Extra configuration §

In this section I will explain how to configure generate your TLS certificate with acme-client and how to configure httpd and relayd to publish cryptpad. I consider it besides the current article because if you have nginx and already a setup to generate certificates, you don't need it. If you start from scratch, it's the easiest way to get the job done.

Acme client man page

Httpd man page and

Relayd man page

From here, I consider you use OpenBSD and you have blank configuration files.

I'll use the domain **kongroo.eu** as an example.

6.1. httpd §

We will use httpd in a very simple way. It will only listen on port 80 for all domain to allow acme-client to work and also to automatically redirect http requests to https.

# cp /etc/examples/httpd.conf /etc/httpd.conf
# rcctl enable httpd
# rcctl start httpd

6.2. acme-client §

We will use the example file as a default:

# cp /etc/examples/acme-client.conf /etc/acme-client.conf

Edit /etc/acme-client.conf and change the last domain block, replace example.com and secure.example.com with your domains, like cryptpad.kongroo.eu and api.cryptpad.kongroo.eu as alternative name.

For convenience, you will want to replace the path for the full chain certificate to have hostname.crt instead of hostname.fullchain.pem to match relayd expectations.

This looks like this paragraph on my setup:

domain kongroo.eu {
        alternative names { api.cryptpad.kongroo.eu cryptpad.kongroo.eu }
        domain key "/etc/ssl/private/kongroo.eu.key"
        domain full chain certificate "/etc/ssl/kongroo.eu.crt"
        sign with buypass
}

Note that with the default acme-client.conf file, you can use *letsencrypt* or *buypass* as a certification authority.

acme-client.conf man page

You should be able to create your certificates now.

# acme-client kongroo.eu

Done!

You will want the certificate to be renewed automatically and relayd to restart upon certificate change. As stated by acme-client.conf man page, add this to your root crontab using crontab -e:

~ * * * * acme-client kongroo.eu && rcctl reload relayd

6.3. relayd §

This configuration is quite easy, replace kongroo.eu with your domain.

Create a /etc/relayd.conf file with the following content:

relayd.conf man page

tcp protocol "https" {
        tls keypair kongroo.eu
}

relay "https" {
        listen on egress port 443 tls
        protocol https
        forward to 127.0.0.1 port 3000
}

Enable and start relayd using rcctl:

# rcctl enable relayd
# rcctl start relayd

6.4. Conclusion §

You should be able to reach your Cryptpad instance using the public URL now. Congratulations!

Kakoune editor cheatsheet

Written by Solène, on 02 December 2020.
Tags: #kakoune #editor #cheatsheet

Comments on Fediverse/Mastodon

This is a simple kakoune cheat sheet to help me (and readers) remember some very useful features.

To see kakoune in action.

Video showing various features in made with asciinema.

Official kakoune website (it has a video)

1. Commands (in command mode) §

1.1. Select from START to END position. §

Use Z to mark start and alt+z i to select unti current position.

1.2. Add a vertical cursor (useful to mimic rectangle operation) §

Type C to add a new cursor below your current cursor.

1.3. Clear all cursors §

Type space to remove all cursors except one.

1.4. Pasting text verbatim (without completion/indentation) §

You have to use "disable hook" command before inserting text. This is done with \i with \ disabling hooks.

1.5. Split selection into cursors §

When you make a selection, you can use s and type a pattern, this will create a new cursor at the start of every pattern match.

This is useful to make replacements for words or characters.

A pattern can be a word, a letter, or even ^ to tell the beginning of each line.

2. How-to §

In kakoune there are often multiples way to do operations.

2.1. Select multiples lines §

2.1.1. Multiples cursors §

Go to first line, press J to create cursors below and press X to select whole lines of every cursors.

2.1.2. Using start / end markers §

Press Z on first line, and alt+z i on last line and then press X to select whole lines of every lines.

2.1.3. Using selections §

Press X until you reach the last line.

2.2. Replace characters or words §

Make a selection and type |, you are then asked for a shell command, you have to use sed.

Sed can be used, but you can also select the lines and split the selection to make a new cursor before each word and replace the content by typing it, using the s command.

2.3. Format lines §

For my blog I format paragraphs so lines are not longer than 80 characters. This can be done by selecting lines and run fmt using a pipe command. You can use other software if fmt doesn't please you.

How to deploy Vger gemini server on OpenBSD

Written by Solène, on 30 November 2020.
Tags: #gemini #openbsd

Comments on Fediverse/Mastodon

0.1. Introduction §

In this article I will explain how to install and configure Vger, a gemini server.

What is the gemini protocol

Short introduction about Gemini: it's a very recent protocol that is being simplistic and limited. Keys features are: pages are written in markdown like, mandatory TLS, no header, UTF-8 encoding only.

0.2. Vger program §

Vger source code

I wrote Vger to discover the protocol and the Gemini space. I had a lot of fun with it, it was the opportunity for me to rediscover the C language with a better approach. The sources include a full test suite. This test suite was unvaluable for the development process.

Vger was really built with security in mind from the first lines of code, now it offers the following features:

  • chroot and privilege dropping, and on OpenBSD it uses unveil/pledge all the time
  • virtualhost support
  • language selection
  • MIME detection
  • handcrafted man page, OpenBSD quality!

The name Vger is a reference to the 1979 first Star Trek movie.

Star Trek: The Motion Picture

0.3. Install Vger §

Compile vger.c using clang or gcc

$ make
# install -o root -g bin -m 755 vger /usr/local/bin/vger

Vger receives requests on stdin and gives the result on stdout. It doesn't take account of the hostname given but a request MUST start with gemini://.

vger official homepage

0.4. Setup on OpenBSD §

Create directory /var/gemini/, files will be served from there.

Create the _gemini user:

useradd -s /sbin/nologin _gemini

Configure vger in /etc/inetd.conf

11965 stream tcp nowait _gemini /usr/local/bin/vger vger

Inetd will run vger` with the _gemini user. You need to take care that /var/gemini/ is readable by this user.

inetd is a wonderful daemon listening on ports and running commands upon connections. This mean when someone connects on the port 11965, inetd will run vger as _gemini and pass the network data to its standard input, vger will send the result to the standard output captured by inetd that will transmit it back to the TCP client.

Tell relayd to forward connections in relayd.conf

log connection
relay "gemini" {
    listen on 163.172.223.238 port 1965 tls
    forward to 127.0.0.1 port 11965
}

Make links to the certificates and key files according to relayd.conf documentation. You can use acme / certbot / dehydrate or any "Let's Encrypt" client to get certificates. You can also generate your own certificates but it's beyond the scope of this article.

# ln -s /etc/ssl/acme/cert.pem /etc/ssl/163.172.223.238\:1965.crt
# ln -s /etc/ssl/acme/private/privkey.pem /etc/ssl/private/163.172.223.238\:1965.key

Enable inetd and relayd at boot and start them

# rcctl enable relayd inetd
# rcctl start relayd inetd

From here, what's left is populating /var/gemini/ with the files you want to publish, the index.md file is special because it will be the default file if no file are requests.

About Language Server Protocol and Kakoune text editor

Written by Solène, on 24 November 2020.
Tags: #kakoune #editor #openbsd

Comments on Fediverse/Mastodon

In this article I will explain how to install a lsp plugin for kakoune to add language specific features such as autocompletion, syntax error reporting, easier navigation to definitions and more.

The principle is to use "Language Server Protocol" (LSP) to communicate between the editor and a daemon specific to a programming language. This can be also done with emacs, vim and neovim using the according plugins.

Language Server Protocol on Wikipedia

For python, _pyls_ would be used while for C or C++ it would be _clangd_.

The how-to will use OpenBSD as a base. The package names may certainly vary for other systems.

0.1. Pre-requisites §

We need _kak-lsp_ which requires rust and cargo. We will need git too to fetch the sources, and obviously kakoune.

# pkg_add kakoune rust git

0.2. Building §

Official building steps documentation

I recommend using a dedicated build user when building programs from sources, without a real audit you can't know what happens exactly in the build process. Mistakes could be done and do nasty things with your data.

$ git clone https://github.com/kak-lsp/kak-lsp
$ cd kak-lsp
$ cargo install --locked --force --path .

0.3. Configuration §

There are a few steps. kak-lsp has its own configuration file but the default one is good enough and kakoune must be configured to run the kak-lsp program when needed.

Take care about the second command if you built from another user, you have to fix the path.

$ mkdir -p ~/.config/kak-lsp
$ cp kak-lsp.toml ~/.config/kak-lsp/

This configuration file tells what program must be used depending of the programming language required.

[language.python]
filetypes = ["python"]
roots = ["requirements.txt", "setup.py", ".git", ".hg"]
command = "pyls"
offset_encoding = "utf-8"

Taking the configuration block for python, we can see the command used is _pyls_.

For kakoune configuration, we need a simple configuration in ~/.config/kak/kakrc

eval %sh{/usr/local/bin/kak-lsp --kakoune -s $kak_session}
hook global WinSetOption filetype=(rust|python|go|javascript|typescript|c|cpp) %{
        lsp-enable-window
}

Note that I used the full path of kak-lsp binary in the configuration file, this is due to a rust issue on OpenBSD.

Link to Rust issue on github

0.4. Trying with python §

To support python programs you need to install python-language-server which is available in pip. There are no package for it on OpenBSD. If you install the program with pip, take care to have the binary in your $PATH (either by extending $PATH to ~/.local/bin/ or by copying the binary in /usr/local/bin/ or whatever suits you).

The pip command would be the following (your pip binary name may change):

$ pip3.8 install --user 'python-language-server[all]'

Then, opening python source file should activate the analyzer automatically. If you add a mistake, you should see ! or * in the most left column.

0.5. Trying with C §

To support C programs, clangd binary is required. On OpenBSD it is provided by the clang-tools-extra package. If clangd is in your $PATH then you should have working support.

0.6. Using kak-lsp §

Now that it is installed and working, you may want to read the documentation.

kak-lsp usage

I didn't look deep for now, the autocompletion automatically but may be slow in some situation.

Default keybindings for "gr" and "gd" are made respectively for "jump to reference" and "jump to definition".

Typing "diag" in the command prompt runs "lsp-diagnostics" which will open a new buffer explaining where errors are warnings are located in your source file. This is very useful to fix errors before compiling or running the program.

0.7. Debugging §

The official documentation explains well how you can check what is wrong with the setup. It consists into starting kak-lsp in a terminal and kakoune separately and check kak-lsp output. This helped me a lot.

Official troubleshooting guide

[7th floor] Nethack story of Sery the tourist

Written by Solène, on 24 November 2020.
Tags: #nethack #gaming

Comments on Fediverse/Mastodon

Sery is back in the fourth floor 4 of the underworld. What mysteries are to be discovered? What enemies will be slayed so we can make our path?

Everything is awesome

Sery is in the fourth floor, she found stairs to go deeper but she also heard coins flipping. Maybe a merchant is around? That would be the right opportunity to buy weapons, armor and food.

               --------------
               |............|
              #.@...........+
              #|............|
              #|..>...$.....|
              #--------------
              ###
                #
                ##
                 #
                 #
                 #
                 #
         -- -----#
              <  #
         |      |
         |      |
         --------

After walking to a new room south-east, she found a large room with a hobbit statue h and a potion on the floor. The potion is not identified, so using it will be very risky.

The large room was a dead end. Back to the previous room Sery was now surrounded by enemies. A gas spore e, a green mold F and a giant bug :! She also felt hungry at the time, but she had to fight. Eggs and pancakes will be for another time.

           --------------
           |.F..........|
          #.:.....@..e..-#
          #|............|#
          #|..>...d.....|#
          #--------------#
          ###            #

While fleeing to the ascending stairs to search a merchant on this floor while escaping enemies, a gecko was blocking the way. Sery had to fight with her fists and fortunately the gecko didn’t oppose much resistance. But a few steps later, a goblin was also in the path. Sery’s dog location is unknown, it was certainly fighting in the previous room. Sery decided to drink a potion to recover from her 2 HP left and go back to the room, in hope the dog can help her.

It worked! The dog was just behind and charged the goblin would die instantly. The dog was starving and ate the goblin freshly killed, Sery was hungry too but preferred eating some pancake that wasn’t fresh, it had better taste than the remaining goblin meat tin can she had in her purse.

                               --------------
                               |            |
                              #.............-#
                              #|            |#
      ---------------         #|  >         |#
      .........o....|         #--------------#
      |.............|         ###            #
      |.......$....@d##         #            #
      --------------- ###       ##           #
                        #        #           #
                        #        #   `##################
                        #        #           #--------- --
                        #        #           #|         h|
                        #-- -----#           #|          |
                        #     <  #           #           |
                         |      |             |          |
                         |      |             |          |
                         --------             ------------

On the first steps in the room, she found a graffiti on the ground:

Atta?king a? ec| vhere the?c is rone i? usually a ?a?al mistakc!

The message didn’t make any sense. The room had a goblin statue and some gold on the ground, it’s all Sery had to know. The room was calm and nothing happened when crossing it. Sery seemed to be blessed!

        -----
        |....##  
        |@..| ###
        -----   #

Nearby she found a very small room with no other way than the entrance. This looked very suspicious and she decided to spend some time looking around for a clue about a secret door. She was right! A few minutes after she started to search, she found a hidden door! The door was not locked, which was surprising. Who knows what was waiting on the other side?

After walking a bit in a small and dark corridor, a new room was here, with an empty box along a wall and a grave in a corner in the opposite side of the room.

             -----
             |    ##                           --------------
            #-   | ###                         |            |
            #-----   #                        #             -#
            ##       #                        #|            |#
             ##      #---------------         #|  >         |#
              ##     #         o    |         #--------------#
      ---------#      |             |         ###            #
      |.......|#      |              ##         #            #
      |........#      --------------- ###       ##           #
      |.......|                         #        #           #
      |(@......                         #        #   `##################
      |......||                         #        #           #--------- --
      ---------                         #        #           #|         h|
                                        #-- -----#           #|          |
                                        #     <  #           #           |
                                         |      |             |          |
                                         |      |             |          |
                                         --------             ------------

The large box was locked! Without lock pick she wasn’t able to open it. After all she went through in the dungeon, anger gave her some strength to break the box padlock after a few kicks in it.

The box contained the following objects:

  • a pyramidal amulet
  • a food ration
  • a black gem
  • two green gems

She still had some room on her bag, it wasn’t too heavy for now so she decided to take everything from the box.

Kicking the box consumed energy and she decided to restart a little, and eat something. The food ration from the box looked very tasty but it may be poisoned or toxic so she avoid it and ate goblin meat in tin can. It wasn’t good, but did the job.

She looked at the grave, it was old and only had engraved words on it which appeared to be

Yes Dear, just a few more minutes…

A corridor in the room was leading to a dead end. There was nothing. Even after searching for a long time, Sery didn’t find any way there so she decided to go back and descend to the next floor.

On a way back, she had to fight monsters: a newt, a sewer rat, a gas spore! After the fights, hunger was back again! It was time for a good meal: goblin meat and food ration. It did hit the spot and Sery felt a lot better.

Fifth floor

In the fifth floor, a potion ! was lying on the ground. There was some light, it wasn’t completely dark, without a lamp or a torch this would be a real problem.

    ---------
    |.......+
    |.......|
    |@......|
    |..d.!..|
    |........
    ------- -

In a corridor leading to a room in the south, she had to kill a coyote in the way. The room had a teleportation trap and an apple %, food!

Going east, she walked through a long corridor until a dead end. After searching for some time she found a way to get a body through a hole and get to the other side. A boulder was in the tunnel but she have been able to push it, fortunately the bolder was rolling fine.

    ---------
    |       +
    |       |
    |<      |
    |       |
    |        
    ------- -
           #
           #
           ##
            #
            ##
             #
             #      #           #                    ##
          --- ------#           #             #      @
          |         #################################`
          |    ^   |
          ----------

Sery found a new room with two potions and a gnome. It was hard for Sery to know if the gnome was hostile

                -.--|--
                +..!G.|
       #        |...!.|
        ########d@....|
        #       |.....|
    ####`       -------

The dog got triggered by the gnome presence and ran to fight the gnome. The gnome was definitely hostile. Sery ended quickly in hand-to-hand combat with the gnome.

The camera’s flash! She thought it should work, after all the camera still had forty seven pictures to take, or enemies to blind.

It worked, the poor creature got blinded, the dog was biting its back. After a few hits, the gnome died, leaving a bow on the ground.

Continuing her way, Sery found the room with the descending stairs. There were a homunculus i and a sewer rat r waiting. She knew the rat was an easy target but the other enemy was unknown. It didn’t appeared friendly and she doubted to be able to kill it without risking her life.

    ---------
    |       +                                               -------------
    |       |                                               |...........|
    |<      |                                               -....>!.....|
    |       |                                               |...........|
    |                                                       ....i....r..|
    ------- -                                               -- -------@--
           #                                                         ##
           #                                                       ###
           ##                                                    ###
            #                                                - --)--
            ##                                               +     |
             #                                      #        |  )  |
             #      #           #                    ########      |
          --- ------#           #             #      #       |     |
          |         #################################`       -------
          |    ^   |
          ----------

Sery decided to go back to the long corridor which had cross ways.

    ---------
    |       +                                               -------------
    |       |                                               |           |
    |<      |                                               -    >!     |
    |       |                                               |           |
    |                                                                   |
    ------- -                                               -- ------- --
           #                                                         ##
           #                                                       ###
           ##                                                    ###
            #                                                -.--|--
            ##                                      #########i@....|
             #                                #######        |..)..|
             #      #           #             #      ########......|
          --- ------#           #             #      #       |)....|
          |         #################################`       -------
          |    ^   |
          ----------

The homunculus was fast! It found Sery back from where they met. Sery was in troubles. The homunculus seemed hard to escape and while fleeing in a corridor, a dwarf zombie Z blocked the way.

She tried to fight it but she lost 9 HP in 2 hits, the beast was very powerful. It was time to drink the random potions she got over the journey. They were unidentified but there was no choice, except praying maybe.

Praying! Sery wasn’t a believer but praying was the best she could do. Her pray was deep and pure, she only wanted to have some hope for her future and her quest.

The Lady heard her pray, Sery got surrounded by a shimmering light. The dwarf zombie attacked Sery but got pulled back by some energy field. Sery felt a lot better, her health was fully recovered and also increased.

                #########-.....|
          #######        |..)..|
          #      #Z@#####......|
          #      #       |)....|
        #########`       -------

Sery got a second chance, she certainly wanted to make a good use of it. At this time, the only thought in her mind was: RUN AWAY

She did run, very fast, to the stairs leading deeper. None enemies made troubles in her retreat.

Sixth floor

No time to look in the room she arrived, Sery got attacked by a brown mold, which in turn was killed by her dog.

    ------
    |....|
    |....|
    |.d@.|
    |....|
    |....|
    |....|
    --.---

The room had only way to the south. Finding a merchant was becoming urgent. Her food supplies were depleting. She had a lot of money but that is not helpful in the middle of the underground among the monsters.

In the south room there was a lichen F, but it seemed peaceful, or guarding the stairs to descend to seventh floor, who knows? The room had no other entrance than the one by which Sery came, but after examining the walls, she found a door.

     ------
     |    |
     |    |
     |  < |
     |    |
     |    |
     |    |
     -- ---
       ####
          #
          #
          ##
      ----- -      -----
      |     |     |....|
      |.F...-#####@....|
      |>    |     |....|
      -------      .!...
                   -----

Nothing unusual in this floor. Continuing her progresses through the tunnels, she ended in a dark room, she wasn’t able to see further than a meter away.

     ------
     |    |              -------------
     |    |             |          .d|
     |  < |            #-          .@|
     |    |            #----       -.-
     |    |            #
     |    |            ##
     -- ---             #
       ####             #
          #             #
          #             #
          ##            #
      ----- -     ------#
      |     |     |    |#
      |     -#####     |#
      |>    |     |    |#
      -------     |     #
                  ------

One more step and she came face to face with a homunculus. Fortunately the dog was just behind and not fighting any other aggressive animals. The dog killed it fast. But then another homunculus came, which also got killed by the dog.

In the end, those homunculus are pretty weak.

Room after room, with only emptiness as a friend, Sery walked for a long time. And then he appeared! The merchant !

     ------
     |    |              -------------                                      ------
     |    |             |            |                                      |????|
     |  < |            #-            |                                      |????|
     |    |            #----       - -                                      |???+|
     |    |            #            ##                                      |??+?|
     |    |            ##            #                                      |+??+|
     -- ---             #            #                                      |.@.
       ####             #        ---- -#                                    -@-
          #             #        |    -#                                     #
          #             #        |    |      |            -- ------        ###
          ##            #        |    -######|                    |        #
      ----- -     ------#        |    |     #|            |                #
      |     |     |    |#        |  <      ##         #### `      |        #
      |     -#####     |#        ------    ######     #   |        ###### - ----
      |>    |     |    |#                       #######   |     _ |     # |    |
      -------     |     #                                 |       |     ##     |
                  ------                                  ---------       ------

He was a bookseller, selling scrolls… Sery was so disappointed by this, she felt helpless for a moment.

FuguITA: OpenBSD live-cd

Written by Solène, on 18 November 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

In this article I will explain how to download and run the FuguITA OpenBSD live-cd, which is not an official OpenBSD project (it is not endorsed by the OpenBSD project), but is available since a long time and is carefully updated at every release and errata published.

FuguITA official homepage

I do like this project and I am running their European mirror, it was really long to download it from Europe before.

Please note that if you have issues with FuguITA, you must report it to the FuguITA team and not report it to the OpenBSD project.

0.1. Preparing §

Download the img or iso file on a mirror.

Mirror list from official project page

The file is gzipped, run gunzip on the img file FuguIta-6.8-amd64-202010251.img.gz (name may change over time because they get updated to include new erratas).

Then, copy the file to your usb memory stick. This can be dangerous if you don't write the file to the correct disk!

To avoid mistakes, I plug in the memory stick when I need it, then I check the last lines of the output of dmesg command which looks like:

sd1 at scsibus2 targ 1 lun 0: <Corsair, Voyager 3.0, 1.00> removable serial.1b1c1a03800000000060
sd1: 15280MB, 512 bytes/sector, 31293440 sectors

This tells me my memory stick is the sd1 device.

Now I can copy the image to the memory stick:

# dd if=FuguIta-6.8-amd64-202010251.img of=/dev/rsd1c bs=10M

Note that I use /dev/rsd1c for the sd1 device. I've added a r to use the raw mode (in opposition of buffered mode) so it gets faster, and the c stands for the whole disk (there is a historical explanation).

0.2. Starting the system §

Boot on your usb memory stick. You will be prompted for a kernel, you can wait or type enter, the default is to use the multiprocessor kernel and there are no reason to use something else.

If will see a prompt "scanning partitions: sd0i sd1a sd1d sd1i" and be asked which is the FuguIta operating device, proposing a default that should be the correct one.

FROM HERE, YOUR KEYBOARD IS IN QWERTY.

Just type enter.

The second question will be the memory disk allowed size (using TMPFS), just press enter for "automatic".

Then, a boot mode will be showed: the best is the mode 0 for a livecd experience.

Official documentation in regards to FuguITA specifics options

Keyboard type will be asked, just type the layout you want. Then answer to questions:

  • root password
  • hostname (you can just press enter)
  • IP to use (v4, v6, both [default])

When prompted for your network interfaces, WIFI may not work because the livecd doesn't have any firmware.

Finally, you will be prompted for C for console or X for xenodm. THERE ARE NO USER except root, so if you start X you can only use root as a user, which I STRONGLY discourage.

You can login console as root, use the two commands "useradd -m username" and "passwd username" to give a password to that user, and then start xenodm.

The livecd can restore data from a local hard drive, this is explained in the start guide of the FuguITA project.

0.3. Conclusion §

Having FuguITA around is very handy. You can use it to check your hardware compatibility with OpenBSD without installing it. Packages can be installed so it's perfect to check how OpenBSD performs for you and if you really want to install it on your computer.

You can also use it as an usb live system to transport OpenBSD anywhere (the system must be compatible) by using the persistent mode, encryption being a feature! This may be very useful for people traveling on lot and who don't necesserarly want to travel with an OpenBSD laptop.

As I said in the introduction, the team is doing a very good job at producing FuguITA releases shortly after the OpenBSD release, and they continuously update every release with new erratas.

Why I use OpenBSD

Written by Solène, on 16 November 2020.
Tags: #openbsd #life

Comments on Fediverse/Mastodon

1. Introduction §

In this article I will share my opinion about things I like in OpenBSD, this may including a short rant about recent open source practices not helping non-linux support.

2. Features §

2.1. Privacy §

There is no telemetry on OpenBSD. It's good for privacy, there is nothing to turn off to disable reporting information because there is no need to.

The default system settings will prevent microphone to record sound and the webcam can't be accessed without user consent because the device is root's by default.

2.2. Secure firefox / chromium §

While the security features added (pledge and mainly unveil) to the market dominating web browsers can be cumbersome sometimes, this is really a game changer compared to using them on others operating systems.

With those security features enabled (by default) the web browsers are ony able to retrieve files in a few user defined directories like ~/Downloads or /tmp/ by default and some others directories required for the browsers to work.

This means your ~/.ssh or ~/Documents and everything else can't be read by an exploit in a web browser or a malicious extension.

It's possible to replicate this on Linux using AppArmor, but it's absolutely not out of the box and requires a lot of tweaks from the user to get an usable Firefox. I did try, it worked but it requires a very good understanding of the Firefox needs and AppArmor profile syntax to get it to work.

2.3. PF firewall §

With this firewall, I can quickly check the rules of my desktop or server and understand what they are doing.

I also use a lot the bandwidth management feature to throttle the bandwidth some programs can use which doesn't provide any rate limiting. This is very important to me.

Linux users could use the software such as trickle or wondershaper for this.

2.4. It's stable §

Apart from the use of some funky hardware, OpenBSD has proven me being very stable and reliable. I can easily reach two weeks of uptime on my desktop with a few suspend/resume every day. My servers are running 24/7 without incident for years.

I rarely go further than two weeks on my workstation because I use the development version -current and I need to upgrade once in a while.

2.5. Low maintenance §

Keeping my OpenBSD up-to-date is very easy. I run syspatch and pkg_add -u twice a day to keep the system up to date. A release every six months requires a bit of work.

Basically, upgrading every six months looks like this, except some specific instructions explained in the upgrade guide (database server major upgrade for example):

# sysupgrade
[..wait..]
# pkg_add -u
# reboot

2.6. Documentation is accurate §

Setting up an OpenBSD system with full disk encryption is easy.

Documentation to create a router with NAT is explained step by step.

Every binary or configuration file have their own up-to-date man page.

The FAQ, the website and the man pages should contain everything one needs. This represents a lot of information, it may not be easy to find what you need, but it's there.

If I had to be without internet for some times, I would prefer an OpenBSD system. The embedded documentation (man pages) should help me to achieve what I want.

Consider configuring a router with traffic shaping on OpenBSD and another one with Linux without Internet access. I'd 100% prefer read the PF man page.

2.7. Contributing is easy §

This has been a hot topic recently. I very enjoy the way OpenBSD manage the contributions. I download the sources on my system, anywhere I want, modify it, generate a diff and I send it on the mailing list. All of this can be done from a console with tools I already use (git/cvs) and email.

There could be an entry barrier for new contributors: you may feel people replying are not kind with you. **This is not true.** If you sent a diff and received critics (reviews) of your code, this means some people spent time to teach you how to improve your work. I do understand some people may feel it rude, but it's not.

This year I modestly contributed to the projects OpenIndiana and NixOS this was the opportunity to compare how contributions are handled. Both those projects use github. The work flow is interesting but understanding it and mastering it is extremely complicated.

OpenIndiana official website

NixOS official website

One has to make a github account, fork the project, create a branch, make the changes for your contribution, commit locally, push on the fork, use the github interface to do a merge request. This is only the short story. On NixOS, my first attempt ended in a pull request involving 6 months of old commits. With good documentation and training, this could be overcome, and I think this method has some advantages like easy continuous integration of the commits and easy review of code, but it's a real entry barrier for new people.

2.8. High quality packages §

My opinion may be biased on this (even more than for the previous items), but I really think OpenBSD packages quality is very high. Most packages should work out of the box with sane defaults.

Packages requiring specific instructions have a README file installed with them explaining how to setup the service or the quirks that could happen.

Even if we lack some packages due to lack of contributors and time (in addition to some packages relying too much on Linux to be easy to port), major packages are up to date and working very well.

I will take the opportunity of this article to publish a complaint toward the general trend in the Open Source.

  • programs distributed only using flatpak / docker / snap are really Linux friendly but this is hostile to non Linux systems. They often make use of linux-only features and the builds systems are made for the linux distribution methods.
  • nodeJS programs: they are made out of hundreds or even thousands of libraries often working fragile even on Linux. This is a real pain to get them working on OpenBSD. Some node libraries embed rust programs, some will download a static binary and use it with no fallback solution or will even try to compile source code instead of using that library/binary from the system when installed.
  • programs using git to build: our build process makes its best to be clean, the dedicated build user **HAS NO NETWORK ACCESS* and won't run those git commands. There are no reasons a build system has to run git to download sources in the middle of the build.

I do understand that the three items above exist because it is easy for developers. But if you write software and publish it, that would be very kind of you to think how it works on non-linux systems. Don't hesitate to ask on social medias if someone is willing to build your software on a different platform than yours if you want to improve support. We do love BSD friendly developers who won't reject OpenBSD specifics patches.

3. What I would like to see improved §

This is my own opinion and doesn't represent the OpenBSD team members opinions. There are some things I wish OpenBSD could improve there.

  • Better ARM support
  • Better performance (gently improving every release)
  • FFS improvements in regards to reliability (I often get files in lost+found)
  • Faster pkg_add -u
  • hardware video decoding/encoding support
  • better FUSE support and mount cifs/smb support
  • scaling up the contributions (more contributors and reviewers for ports@)

I am aware of all the work required here, and I'm certainly not the person who will improve those. This is not a complain but wishes.

Unfortunately, everyone knows OpenBSD features come from hard work and not from wishes submitted to the developers :)

When you think how little the team is in comparison to the other majors OS, I really think a good and efficient job is done there.

Toward an automated tracking of OpenBSD ports contributions

Written by Solène, on 15 November 2020.
Tags: #openbsd #automation

Comments on Fediverse/Mastodon

Since my previous article about a continous integration service to track OpenBSD ports contribution I made a simple proof of concept that allowed me to track what works and what doesn't work.

0.1. The continuous integration goal §

A first step for the CI service would be to create a database of diffs sent to ports. This would allow people to track what has been sent and not yet committed and what the state of the contribution is (build/don't built, apply/don't apply). I would proceed following this logic:

  • a mail arrive and is sent to the pipeline
  • it's possible to find a pkgpath out of the file
  • the diff applies
  • distfiles can be fetched
  • portcheck is happy

Step 1 is easy, it could be mail dumped into a directory that get scanned every X minutes.

Step 2 is already done in my POC using a shell script. It's quite hard and required tuning. Submitted diffs are done with diff(1), cvs diff or git diff. The important part is to retrieve the pkgpath like "lang/php/7.4". This allow testing the port exists.

Step 3 is important, I found three cases so far when applying a diff:

  • it works, we can then register in the database it can be used to build
  • it doesn't work, human investigation required
  • the diff is already applied and patch think you want to reverse it. It's already committed!

Being able to check if a diff is applied is really useful. When building the contributions database, a daily check of patches that are known to apply can be done. If a reverse patch is detected, this mean it's committed and the entry could be delete from the database. This would be rather useful to keep the database clean automatically over time.

Step 4 is an inexpensive extra check to be sure the distfiles can be downloaded over the internet.

Step 5 is also an inexpensive check, running portinfo can reports easy to fix mistakes.

All the steps only require a ports tree. Only the step 4 could be tricked by someone malicious, using a patch to make the system download very huge files or files with some legal concerns, but that message would also appear on the mailing list so the risk is quite limited.

To go further in the automation, building the port is required but it must be done in a clean virtual machine. We could then report into the database if the diff has been producing a package correctly, if not, provide the compilation log.

0.2. Automatic VM creation §

Automatically creating an OpenBSD-current virtual machine was tricky but I've been able to sort this out using vmm, rsync and upobsd.

The script download the last sets using rsync, that directory is served from a mail server. I use upobsd to create an automatic installation with bsd.rd including my autoinstall file. Then it gets tricky :)

vmm must be started with its storage disk AND the bsd.rd, as it's an auto install, it will reboot after the install finishes and then will install again and again.

I found that using the parameters "-B disk" would make the vm to shutdown after installation for some reasons. I can then wait for the vm to stop and then start it without bsd.rd.

My vmm VM creation sequence:

upobsd -i autoinstall-vmm-openbsd -m http://localhost:8080/pub/OpenBSD/
vmctl stop -f -w integration
vmctl start -B disk -m 1G -L -i 1 -d main.qcow2 -b autobuild_vm/bsd.rd integration
vmctl wait integration
vmctl start -m 1G -L -i 1 -d main.qcow2 integration

The whole process is long though. A derivated qcow image could be used after creation to try each port faster until we want to update the VM again.

Multplies vm could be used at once to make parallel testing and make good use of host ressources.

0.3. What's done so far §

I'm currently able to deposite email as files in a directory and run a script that will extract the pkgpath, try to apply the patch, download distfiles, run portcheck and run the build on the host using PORTS_PRIVSEP. If the ports compiled fine, the email file is deleted and a proper diff is made from the port and moved into a staging directory where I'll review the diffs known to work.

This script would stop on blocking error and write a short text report for each port. I intended to sent this as a reply to the mailing at first, but maintaining a parallel website for people working on ports seems a better idea.

The Nethack story of Sery the tourist

Written by Solène, on 15 November 2020.
Tags: #nethack #gaming

Comments on Fediverse/Mastodon

First episode of maybe a serie!

Let’s play NetHack and write a story along the way. I find nethack to be a wonderful game despite its quite simple graphics. In this game, you can do more actions than in any modern games. I can dip a towel in a fountain to make it wet, and wear it on my head. Maybe it would protect me from heat? Who knows.

As this leaves a lot of place for the imagination, every serious nethack game I play, I create a story in my head and try to imagine the various situations, so maybe I could write them down?

Welcome to the underworld Gehennom, you will read the story of Sery the human female neutral tourist and her dog. She has to find the Amulet of Yendor and come back to the surface, for some reasons.

@ is Sery and d is her dog.

Arrival - first floor

{ is a fountain, # a sink, - an open door and + a closed door.

In her inventory, she has 875 gold, tourists are rich! 24 darts to throw at enemies, 2 fortunes cookies, some various food (goblin meat in tin can, eggs, carrot, apple, pancakes…), 4 scrolls of magic mapping, 2 healing potions, and expensive camera and an uncursed credit card.

       ---+---------
       |......{....-
       |@.........#|
       |d..........|
       -------------

She went to the closed door but it resisted, after kicked it three times, the door opened! After walking around in tunnel, she only found empty rooms, leading to others tunnels.

# are corridors (when they are not sinks in a room).

                             --------
                            #   ..  |
                            #|  ..  |
                            #|  ..  |
                            #---|----
                            #   ##
                          ###########
                          ##     #
                          #      #
                          #      #
          ----------|---###   ##d@##
          |             #     # ###
          |            |      #---.---------
          |            -#######|..... {    -
          |            |       |<....     #|
          |            |       |.....      |
          --------------       -------------

At the end of a corridor, Sery was stuck but after searching around for some secrets passage, she found a hidden passage to the first room. Back to square one.

                             --------
                            #       |
                            #|      |
                            #|      |
                            #---|----
                            #   ##
                          ###########
                          ##     #           # #
                          #      #       #######
                          #      #       #   #
          ----------|---###   ############  #d
          |             #     # ###         @
          |            |      #--- ---------#
          |            -#######|      {....-#
          |            |       |<   ......#|
          |            |       |   ........|
          --------------       -------------

After she heard some noise in a corridor, she stumbled on a boulder \` but it is impossible to move it to clear the corridor.

A new room was found, with a large box ( in it. What could be in this box?

           ------
           |....|
         ##d.@..+
        ###|....|
        ## |....|
        ##`|.(..|
        #  |....|
        #  ------

While walking toward the box, her dog suddenly disappeared, falling in a trap door! Sery shorten her exploration of the first level after opening the box to look after her dog.

The large box was locked, without weapon or tools to unlock it, Sery kicked the large box a dozen time so it opened. What a disappointment when she was it was empty!

Second floor

            ----------
            |......@.|
            .........|
            |........|
            |....>...|
            |.....$..|
            ----------

Sery jumped into the trap to descend to the level below, her dog wasn’t in the room though. There were five gold to loot and stairs to descend to the third level. She needed to find her dog before continuing exploration to third level.

In the adjacent corridor, the dog was found sound and safe!

After continuing the exploration, a room was found with enemies!

F lichen, o goblin and a : newt! That was a lot of enemies for a simple tourist. She wanted to pull them into a corridor and let her dog take care of the enemies. This was a good spartiate strategy after all!

                                ----------
                                |        |
                               #         |
                               #|        |
                               #|    >   |
                               #|        |
                               #----------
                               #
                               #
         --------              #
         |.......              #
         .......F|      -------#
         |:....o.@d#####......|#
         |.......|      |      #
         |.......       |     |
         |......        |     |
         -------        -------

Unfortunately, when a lichen is in contact with you, you can’t escape. It took a while for Sery to kill the lichen and retreat in the corridor, she receive a few hits from the lichen and the goblin (HP 6/10). She heard some noises while staying in the corridor, after coming back in the room, the dog finished to kill the newt and the goblin seemed to ran away.

             -------- 
             |.....o. 
             ........|
             |.....d.@
             |.......|
             |....... 
             |......  
             -------  

The dog was then attacking the goblin and killed it rather quickly. This was really fortunate that Sery was in company of her dog.

After walking a bit to continue the exploration, Sery stumbled on a sewer rat, she got hit rather hard and didn’t had much HP left! While retreating to the last room, looking for the dog who stayed back eating the goblin corp, the dog came back to her bringing a iron skull cap certainly found on the dead goblin. In one bit, the dog killed the rat.

After some rest to recover a few HP, Sery went back to the exploration. The exploration was quiet and easy, rooms with unlocked doors, she found the stairs to go upstairs. Nothing of interested was to be found, so it was time to go to the third level. A newt and a lichen were encountered in the corridors but opposed little resistance to the dog.

    ---------                                                   ----------
    |       |                                                   |........|
    |       |       ----------                                 #.........|
    |       |       |        |                                 #|.d..@...|
    |       |       |        |                                 #|F...>...|
    |       |       |        |                                 #|........|
    - -|--- -#   ###-        |                                 #----------
      ### ####  ##  |        |                                 #
       #  `##`###   --- ------                                 #
       ###     ###    ##                 ---------             #
         #####  #     #####              |       |             #
    ---------|-##      ######          ##        |      -------#
    |         |#      -- ---|-----     # |       -######      |#
    |         |#      |          |   ### |       |      |      #
    |         |#      |          |   #   |       |      |     |
    |         -#      |           ####   |       |      |     |
    | <       |       ------------       ---------      -------
    -----------

Third floor

The room where Sery arrived in the third level had an enemy, a huge x bug and some money in a corner near a door.

                      --------------
                      |...@........|
                      |....d.......|
                      ....x.......$|
                      |............+
                      --------------

The door required two kicks to be opened.

In the next room, Sery saw a bug before entering, so she immediately swapped her place with her dig in the corridor to let her defender do their job.

< are upstairs stairs.

                      --------------
                      |   <        |
                      |            |
                                   |
                      |             ##
                      -------------- #
                                     ##    --+-
                                      ##d@.x..|
                                            .$|
                                              .
                                              -

As usual, the dog took care of the enemies. A new room was found, multiples windows, some opening in previous rooms wasn’t explored yet too. There were lot of exploration to be done in this area.

                                   --------
                                   |......+
                                   |......|
                                   +>.{...|
              --------------       |......|
              |   <        |       |....@.|
              |            |       -----.--     ...
                           |        ######
              |             ##       #####
              -------------- #       #
                             ##   ---|-
                              ####    |
                                  |   |
                                  |    
                                  -----

While exploring, Sery got to fight a giant rat, she didn’t know where her dog was so she had to fight for real this time.

                                                           --------
             ----                                          |      +
             ....                                          |      |
              ..                     ######################-> {   |
               r                     #--------------       |      |
              #@#####                #|   <        |       |      |
              #     #              ###|            |       ----- --        
                    ##             ###             |        ######
                     #            ##  |             ##       #####
                     #            ##  -------------- #       #
                     #             #                 ##   ---|-
                     ##        #####                  ####    |
                    #- ------  ####                       |   |
                     +      |  #                          |    
                     | >     ###                          -----
                     |      |###
                     |      |
                     --------

Thinking about her inventory, she panicked and used her camera. The flash blinded the giant rat and he ran away! Unfortunately, another giant rat came from the left corridor. She tried to use her camera again but it didn’t work as expected as the giant was still standing in the corridor. The blinding effect didn’t seem very effective because a few seconds later, the first giant rat was back again!

      ----     
      ....     
       ..      
        r      
       r@##### 
       #     # 
         ##

She had no choice but run away, maybe at least fight then but one at a time in a corridor. She want backward, suffered from a giant rat bite and found her dog on the way, who came to the rescue. While she let her dog fighting, a third rat came from behind, this one, she really had to fight, no escape was possible with the dog fighting two rats in the corridor on the other side.

Camera flash, it worked! Time to throw darts, one dart was enough to kill the rat but she missed it a few times. The rat never missed a bite, Sery was in poor health at this moment.

The dog killed the two rats and she was safe, for now.

While walking around to find her way, she got surprised by a giant zombie Z who hit her hard. She had only 1 health point left. Death was close. What she could do? Try the camera flash, drink a potion, escape until her dog run and try to bite the zombie?

She decided to try the health potion and then, support enough hits from the zombie to blind it while the dog behind it was killing the undead living. It was a good idea, at the moment she dunked the healing potion, the zombie hit her, losing one health point, she would be dead if she didn’t drink that potion, then the dog killed the monster and our duo leveled up!

It was time to finish exploring and get deeper in the underworld. A = ring was on the ground in the last room. It was silver ring.

                                                             --------
               --------------                                |      +
              #.            |                                |      |
              #|            |          ######################-> {   |
              #-- -----------          #--------------       |      |
              #########                #|   <        |       |      |
                #     #              ###|            |       ----- --        
                #     ##             ###             |        ######
     -----------#      #            ##  |             ##       #####
     |.......=@.#      #            ##  -------------- #       #
     |.........|       #             #                 ##   ---|-
     |.........        ##        #####                  ####    |
     |....`....|      #- ------  ####                       |   |
     |..  .....|       +      |  #                          |    
     ---  ------       | >     ###                          -----
                       |      |###
                       |      |
                       --------

It would be foolish to wear the ring without identifying it first, it could be a cursed ring you can’t remove that makes you blind or provoke some unwanted effects.

Fourth floor

Arriving at the fourth floor, Sery found a green gem. Feeling this floor would be quite complicated, she decided to read one of her mapping scroll.

       -------
      --     |                                                    ---  ---    ---
      |  --  |           ------                       --- ----   -- ---- --  -- --
      | -|-- |           |  | ---                    -- ---  --  |        ----   |
      |  --| |           |      ----                --        |  |        >      |
      |   || ----------  --      | --------------- --         |  ---             |
      | | ||          -------        | --      | ---         --    -- ---        --
      | |--|  -------     ---                                | ---- --- --        |
      | |  | --     ---                                      | |  |---- --       --
      | -- | --       -------     ----       --  - --        ---  --  | |       --
     --  --|  |             |    --  |       |--   --- ---            ---       |
     |    |-- |             ---  |   --     -| ---  --------                    |
     |    | | ---------       ----    |      --  --      --|            ---     |
     | -- | |.....--.@--             --       |   ------   |-- --      -- |     |
     ---| | ----.......|        ------        |        |-  | ---|-    --  |     |
       -- |   --......-|       --  |         --        |   ---  |    --   --   --
     ---  |  --........|      --             |         |     |  |  ---     -----
    --   --  |.........|      |         -- ---         --    |  ----
    |   --   |......--.|      |     --  |---            ---  |
    --  |    --.|.------      ---- ------                 ----
     ----     -----              ---

After the whole map got reveal in her mind, she got face to face with a dwarf h wielding a dagger. He really didn’t seem friendly but he didn’t attack her yet.

The whole area was very dark, without a torch or a light source, exploring this level would be very tedious.

After exploring the room, looking for interesting loots on the ground, the dwarf attacked her. This was a very dolorous stabbing. Sery retreated back to the upper stairs, she wanted to reach the level below through the other stairs on this level. In the room, she found her dog which stayed behind, fighting a gecko and a giant rat.

She started to feel hungry, hopefully she went to the underworld with a lot of food. She decided to eat a fortune cookie. When cracking it, she found a paper saying: They say that you should never introduce a rope golem to a succubus. This didn’t make much sense to her though.

While walking toward the other stairs, Sery found a graffiti on the ground: ??urist? we?r shirts loud enougn to wake t?e ?e?d.. As for the fortune cookie, this didn’t make much sense.

On her way, she fought various enemies: red mold, newt, rats, found a banana. Descending the stairs, she was surprised to see they didn’t lead to the forth floor with the dwarves, it was a parallel fourth floor. Could it be possible?? There were a newt and money in the room, it wasn’t dark.

             -- -----
             .....@..
             |....d.|
             |...:.$|
             --------

She was angry.

The dog jumped on the newt and killed it. The duo got experience to reach level four. The dog, being a little dog, did grow up into a dog.

After a short rest to eat and recover health, Sery went back in corridors to find a way and continue her quest.

                   --------------
                   |............|
                  #.@...........+
                  #|............|
                  #|..>...$.....|
                  #--------------
                  ###
                    #
                    ##
                     #
                     #
                     #
                     #
             -- -----#
                  <  #
             |      |
             |      |
             --------

In the room she found stairs to go in the level below, would it be a good idea to descend now or should she explore the area first? She had lot of money, finding a merchant to buy armors and weapons would be a good idea.

To be continued

It’s all for today! Please tell me if you enjoyed it!

Full featured Slackware email server with sendmail and cyrus-imapd

Written by Solène, on 14 November 2020.
Tags: #slackware #email

Comments on Fediverse/Mastodon

This article is about making your own mail server using Slackware linux distribution, sendmail and cyrus-imap. This choice is because I really love Slackware and I also enjoy non-mainstream stacks. While everyone would recommend postfix/dovecot, I prefer using sendmail/cyrus-imap. Please not this article contain ironical statements, I will try to write them with some emphasis.

While some people use fossil fuel cars, some people use Slackware.

If you are used to clean, reproducible and automated deployments, the present how-to is the totally opposite. This is the /Slackware/ way.

Slackware

Slackware is one of the oldest (maybe the oldest with debian) linux distribution out there and it’s still usable. The last release (14.2) is 4 years old but there are still security updates. I choose to use the development branch slackware-current for this article.

I discovered an alternative to Windows in the early 2000' with a friend showing me a « Linux » magazine, featuring Slackware installation CDs and the instructions to install. It was my very first contact with Linux and open source ever. I used Slackware multiple times over time, and it was always a great system for me on my main laptop.

The Slackware specifics could be said as: “not changing much” and “quite limited”. Slackware never change much between releases, from 2010 to 2020, it’s pretty much the same system when you use it. I say it’s rather limited, package wise, the default Slackware installation requires like 15 GB on your disk because it bundles KDE and all the kde apps, a bunch of editors (emacs,vim,vs,elvis), lot of compilers/interpreter (gcc, llvm, ada, scheme, python, ruby etc..). While it provides a LOT of things out of the box, you really get all Slackware can offer. If something isn’t in the packages, you need to install it yourself.

Full Disk Encryption or nothing

I recommend to EVERYONE the practice of having a full disk encryption (phone, laptop, workstation, servers). If your system get stolen, you will only lose hardware when you use full disk encryption.

Without encryption, the thief can access all your data forever.

Slackware provides a file README_CRYPT.txt explaining how to install on an encrypted partition. Don’t forget to tell the bootloader LILO about the initrd, and keep in mind the initrd must be recreated after kernel upgrade

Use ntpd

It’s important to have a correct time on your server.

# chmod +x /etc/rc.d/rc.ntpd
# /etc/rc.d/rc.ntpd start

Disable ssh password authentication

In /etc/ssh/sshd_config there are two changes to do:

Turn UsePam yes into UsePam no and add PasswordAuthentication.

Changes can be applied by restarting ssh with /etc/rc.d/rc.sshd restart.

Before enabling this, don’t forget to deploy your public key to an user who is able to become to root.

Get a SSL certificate

We need a SSL certificate for the infrastructure, so we will install certbot. Unfortunately, certbot-auto doesn’t work on Slackware because the system is unsupported. So we will use pip and call certbot in standalone mode so we don’t need a web server.

# pip3 install certbot
# certbot certonly --standalone -d mydomain.foobar -m usernam@example

My domain being kongroo.eu the files are generated under /etc/letsencrypt/live/kongroo.eu/.

Configure the DNS

Three DNS entries have to be added for a working email server.

  1. SPF to tell the world which addresses have the right send your emails
  2. MX to tell the world which addresses will receive the emails and in which order
  3. DKIM (a public key) to allow recipients to check your emails really comes from your servers (signed used a private key)
  4. DMARC to tell recipient what to do with mails not respecting SPF

SPF

Simple, add an entry with v=spf1 mx if you want to allow your MX servers to send emails. Basically, for simple setups, the same server receive and send emails.

@ 1800 IN SPF "v=spf1 mx"

MX

My server with the address kongroo.eu will receive the emails.

@ 10800 IN MX 50 kongroo.eu.

DKIM

This part will be a bit more complicated. We have to generate a pair of public and private keys and run a daemon that will sign outgoing emails with the private key, so recipients can verify the emails signature using the public key available in the DNS. We will use opendkim, I found this very good article explaining how to use opendkim with sendmail.

Opendkim isn’t part of slackware base packages, fortunately it is available in slackbuilds, you can check my previous article explaining how to setup slackbuilds.

# groupadd -g 305 opendkim
# useradd -r -u 305 -g opendkim -d /var/run/opendkim/ -s /sbin/nologin \
    -c  "OpenDKIM Milter" opendkim
# sboinstall opendkim

We want to enable opendkim at boot, as it’s not a service from the base system, so we need to “register” it in rc.local and enable both.

Add the following to /etc/rc.d/rc.local:

if [ -x /etc/rc.d/rc.opendkim ]; then
  /etc/rc.d/rc.opendkim start
fi

Make the scripts executable so they will be run at boot:

# chmod +x /etc/rc.d/rc.local
# chmod +x /etc/rc.d/rc.opendkim

Create the key pair:

# mkdir /etc/opendkim
# cd /etc/opendkim
# opendkim-genkey -t -s default -d kongroo.eu

Get the content of default.txt, we will use it as a content for a TXT entry in the DNS, select only the content between parenthesis without double quotes: your DNS tool (like on Gandi) may take everything without warning which would produce an invalid DKIM signature. Been there, done that.

The file should looks like:

default._domainkey      IN      TXT     ( "v=DKIM1; k=rsa; t=y; " "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC5iBUyQ02H5sfS54hg155eQBxtMuhcwB4b896S7o97pPGZEiteby/RtCOz9VV2TOgGckz8eOEeYHnONdlnYWGv8HqVwngPWJmiU7xbyoH489ZkG397ouEJI4mBrU9ZTjULbweT2sVXpiMFCalNraKHMVjqgZWxzqoE3ETGpMNNSwIDAQAB" )

But the content I used for my entry at gandi is:

v=DKIM1; k=rsa; t=y; " "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC5iBUyQ02H5sfS54hg155eQBxtMuhcwB4b896S7o97pPGZEiteby/RtCOz9VV2TOgGckz8eOEeYHnONdlnYWGv8HqVwngPWJmiU7xbyoH489ZkG397ouEJI4mBrU9ZTjULbweT2sVXpiMFCalNraKHMVjqgZWxzqoE3ETGpMNNSwIDAQAB

Now we need to configure opendkim to use our keys. Edit /etc/opendkim.conf to changes the following lines already there:

Domain                  kongroo.eu
KeyFile /etc/opendkim/default.private
ReportAddress           postmaster@kongroo.eu

Dmarc

We have to tell DMARC, this may help being accepted by big corporate mail servers.

_dmarc.kongroo.eu.   IN TXT    "v=DMARC1;p=none;pct=100;rua=mailto:postmaster@kongroo.eu;"

This will tell the recipient that we don’t give specific instruction to what to do with suspicious mails from our domain and tell postmaster@kongroo.eu about the reports. Expect daily mail from every mail server reached in the day to arrive on that address.

Install Sendmail

Unfortunately Slackware team dropped sendmail in favor to postfix in the default install, this may be a good thing but I want sendmail. Good news: sendmail is still in the extra directory.

I wanted to use citadel but it was really complicated, so I went to sendmail.

Installation

Download the two sendmail txz packages on a mirror in the “extra” directory: https://mirrors.slackware.com/slackware/slackware64-current/extra/sendmail/

Run /sbin/installpkg on both packages.

Configuration

We will disable postfix.

# sh /etc/rc.d/rc.postfix stop
# chmod -x /etc/rc.d/rc.postfix

Enable sendmail and saslauthd

# chmod +x /etc/rc.d/rc.sendmail
# chmod +x /etc/rc.d/rc.saslauthd

All the configuration will be done in /usr/share/sendmail/cf/cf, we will use a default template from the package. As explained in the cf files, we need to use a template and rebuild from this directory containing all the macros.

# cp sendmail-slackware-tls-sasl.mc /usr/share/sendmail/cf/cf/config.mc

Every time we want to rebuild the configuration file, we need to apply the m4 macros to have the real configuration file.

# sh Build config.mc
# cp config.cf /etc/mail/sendmail.cf

My config.mc file looks like this (I stripped the comments):

include(`../m4/cf.m4')
VERSIONID(`TLS supporting setup for Slackware Linux')dnl
OSTYPE(`linux')dnl
define(`confCACERT_PATH', `/etc/letsencrypt/live/kongroo.eu/')
define(`confCACERT', `/etc/letsencrypt/live/kongroo.eu/cert.pem')
define(`confSERVER_CERT', `/etc/letsencrypt/live/kongroo.eu/fullchain.pem')
define(`confSERVER_KEY', `/etc/letsencrypt/live/kongroo.eu/privkey.pem')
define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl
define(`confTO_IDENT', `0')dnl
FEATURE(`use_cw_file')dnl
FEATURE(`use_ct_file')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(`access_db', `hash -T<TMPF> /etc/mail/access')dnl
FEATURE(`blocklist_recipients')dnl
FEATURE(`local_procmail',`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`always_add_domain')dnl
FEATURE(`redirect')dnl
FEATURE(`no_default_msa')dnl
EXPOSED_USER(`root')dnl
LOCAL_DOMAIN(`localhost.localdomain')dnl
INPUT_MAIL_FILTER(`opendkim', `S=inet:8891@localhost')
MAILER(local)dnl
MAILER(smtp)dnl
MAILER(procmail)dnl
define(`confAUTH_OPTIONS', `A p y')dnl
define(`confAUTH_MECHANISMS', `LOGIN PLAIN DIGEST-MD5 CRAM-MD5')dnl
TRUST_AUTH_MECH(`LOGIN PLAIN DIGEST-MD5 CRAM-MD5')dnl
DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl
DAEMON_OPTIONS(`Port=smtps, Name=MSA-SSL, M=Esa')dnl
LOCAL_CONFIG
O CipherList=ALL:!ADH:!NULL:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:-LOW:+SSLv3:+TLSv1:-SSLv2:+EXP:+eNULL

Create the file /etc/sasl2/Sendmail.conf with this content:

pwcheck_method:saslauthd

This will tell sendmail to use saslauthd for PLAIN and LOGIN connections. Any SMTP client will have to use either PLAIN or LOGIN.

If you start sendmail and saslauthd, you should be able to send e-mails with authentication.

We need to edit /etc/mail/local-host-names to tell sendmail for which domain it should accept local deliveries.

Simply add your email domain:

kongroo.eu

The mail logs are located under /var/log/maillog, every mail sent well signed with DKIM should appear under a line like this:

[time] [host] sm-mta[2520]: 0AECKet1002520: Milter (opendkim) insert (1): header: DKIM-Signature:  [whole signature]

Configure DKIM

This has been explained in a subsection of sendmail configuration. If you didn’t read this step because you don’t want to setup dkim, you missed information required for the next steps.

Install cyrus-imap

Slackware ships with dovecot in the default installation, but cyrus-imapd is available in slackbuilds.

The bad news is that the slackbuild is outdated, so here it a simple patch to apply in /usr/sbo/repo/network/cyrus-imapd. This patch also fixes a compilation issue.

diff --git a/network/cyrus-imapd/cyrus-imapd.SlackBuild b/network/cyrus-imapd/cyrus-imapd.SlackBuild
index 48e2c54e55..251ca5f207 100644
--- a/network/cyrus-imapd/cyrus-imapd.SlackBuild
+++ b/network/cyrus-imapd/cyrus-imapd.SlackBuild
@@ -23,7 +23,7 @@
 #  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     
 PRGNAM=cyrus-imapd
-VERSION=${VERSION:-2.5.11}
+VERSION=${VERSION:-2.5.16}
 BUILD=${BUILD:-1}
 TAG=${TAG:-_SBo}
     
@@ -107,6 +107,8 @@ CXXFLAGS="$SLKCFLAGS" \
   $DATABASE \
   --build=$ARCH-slackware-linux
     
+sed -i'' 's/gettid/_gettid/g' lib/cyrusdb_berkeley.c
+
 make PERL_MM_OPT='INSTALLDIRS=vendor'
 make install DESTDIR=$PKG
     
diff --git a/network/cyrus-imapd/cyrus-imapd.info b/network/cyrus-imapd/cyrus-imapd.info
index 99b2c68075..6ae26365dc 100644
--- a/network/cyrus-imapd/cyrus-imapd.info
+++ b/network/cyrus-imapd/cyrus-imapd.info
@@ -1,8 +1,8 @@
 PRGNAM="cyrus-imapd"
 VERSION="2.5.11"
 HOMEPAGE="https://www.cyrusimap.org/"
-DOWNLOAD="ftp://ftp.cyrusimap.org/cyrus-imapd/cyrus-imapd-2.5.11.tar.gz"
-MD5SUM="674083444c36a786d9431b6612969224"
+DOWNLOAD="https://github.com/cyrusimap/cyrus-imapd/releases/download/cyrus-imapd-2.5.16/cyrus-imapd-2.5.16.tar.gz"
+MD5SUM="d5667e91d8e094ef24560a148e39c462"
 DOWNLOAD_x86_64=""
 MD5SUM_x86_64=""
 REQUIRES=""

You can apply it by carefully copying the content in a file and use the command patch.

We can now proceed with cyrus-imapd compilation and installation.

# env DATABASE=sqlite sboinstall cyrus-imapd

As explained in the README file shown during installation, we need to do a few instructions.

# mkdir -m 750 -p /var/imap /var/spool/imap /var/sieve
# chown cyrus:cyrus /var/imap /var/spool/imap /var/sieve
# su - cyrus
# /usr/doc/cyrus-imapd-2.5.16/tools/mkimap
# logout

Add the following to /etc/rc.d/rc.local to enable cyrus-imapd at boot:

if [ -x /etc/rc.d/rc.cyrus-imapd ]; then
  /etc/rc.d/rc.cyrus-imapd start
fi

And make the rc script executable:

# chmod +x /etc/rc.d/rc.cyrus-imapd

The official cyrus documentation is very well done and was very helpful while writing this.

The configuration file is /etc/imapd.conf:

configdirectory: /var/imap
partition-default: /var/spool/imap
sievedir: /var/sieve
admins: cyrus
sasl_pwcheck_method: saslauthd
allowplaintext: yes
tls_server_cert: /etc/letsencrypt/cyrus/fullchain.pem
tls_server_key:  /etc/letsencrypt/cyrus/privkey.pem
tls_client_ca_dir: /etc/ssl/certs

There is another file /etc/cyrusd.conf used but we don’t need to make changes in it.

We will have to copy the certificates into a separate place and allow cyrus user to read them. This will have to be done every time the certificate are renewed. Let’s add the certbot command so we can use this script as a cron.

#!/bin/sh
DOMAIN=kongroo.eu
LIVEDIR=/etc/letsencrypt/live/$DOMAIN/
DESTDIR=/etc/letsencrypt/cyrus/

certbot certonly --standalone -d $DOMAIN -m usernam@example
mkdir -p $DESTDIR
install -o cyrus -g cyrus -m 400 $LIVEDIR/fullchain.pem $DESTDIR
install -o cyrus -g cyrus -m 400 $LIVEDIR/privkey.pem $DESTDIR
/etc/rc.d/rc.sendmail restart
/etc/rc.d/rc.cyrus-imapd restart

Add a crontab entry to run this script once a day, using crontab -e to change root crontab.

MAILTO=""
PATH=/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin
0 5 * * * sh /root/renew_certs.sh

Starting the mail server

We prepared the mail server to be working on reboot, but the services aren’t started yet.

# /etc/rc.d/rc.saslauthd start
# /etc/rc.d/rc.sendmail start
# /etc/rc.d/rc.cyrus-imapd start
# /etc/rc.d/rc.opendkim start

Adding a new user

Add a new user to your system.

# useradd $username
# passwd $username

For some reasons the user mailboxes must be initialized. The same password must be typed twice (or passed as parameter using -w $password).

# USER=foobar
# DOMAIN=kongroo.eu
# echo "cm INBOX" | rlwrap cyradm -u $USER $DOMAIN
Password:
IMAP Password:

Voila! The user should be able to connect using IMAP and receive emails.

Check your email setup

You can use the web service Mail tester by sending an email. You could copy/paste a real email to avoid having a bad mark due to spam recognition (which happens if you send a mail with a few words). The bad spam core isn’t relevant anyway as long as it’s due to the content of your email.

Conclusion

I had real fun writing this article, digging hard in Slackware and playing with unusual programs like sendmail and cyrus-imapd. I hope you will enjoy too as much as I enjoyed writing it!

If you find mistakes or bad configuration settings, please contact me so, I will be happy to discuss about the change and fix this how-to.

Nota Bene: Slackbuilds aren’t mean to be used on the current version, but really on the last release. There is a github repository carrying the -current changes on a github repository https://github.com/Ponce/slackbuilds/.

How to use Slackware community slackbuilds

Written by Solène, on 13 November 2020.
Tags: #slackware

Comments on Fediverse/Mastodon

In today article I will explain how to use Slackbuilds repository on a Slackware current system.

You can read the Documentation of slackbuilds for more information.

We will first install sbotools package which make the use of slackbuilds a lot easier: like a proper ports tree. As it’s preferable to let the tools create the repository, we will install them without downloading the whole slackbuild repository.

Download the slackbuild from this page, extract it and cd into the new directory.

$ tar xzvf sbotools.tar.gz
$ cd sbotools
$ . ./sbotools.info
$ wget $DOWNLOAD
$ md5sum $(basename $DOWNLOAD)
$ echo $MD5SUM

The two md5 string should match.

Now, run the build as root

$ sudo sh sbotools.SlackBuild
[lot of text]
Slackware package /tmp/sbotools-2.7-noarch-1_SBo.tgz created.

Now you can install the created package using

$ sudo /sbin/installpkg /tmp/sbotools-2.7-noarch-1_SBo.tgz

We now have a few programs to use the slackbuilds repository, they all have their own man page:

  • sbocheck
  • sboclean
  • sboconfig
  • sbofind
  • sboinstall
  • sboremove
  • sbosnap
  • sboupgrade

Creating the repository

As root, run the following command:

# sbosnap fetch
Pulling SlackBuilds tree...
Cloning into '/usr/sbo/repo'...
remote: Enumerating objects: 59, done.
remote: Counting objects: 100% (59/59), done.
remote: Compressing objects: 100% (59/59), done.
remote: Total 485454 (delta 31), reused 14 (delta 0), pack-reused 485395
Receiving objects: 100% (485454/485454), 134.37 MiB | 1.20 MiB/s, done.
Resolving deltas: 100% (337079/337079), done.
Updating files: 100% (39863/39863), done.

The slackbuilds tree is now installed under /usr/sbo/repo. This could be configured before using sboconfig -s /home/solene which would create a /home/solene/repo.

Searching a port

One can use the command sbofind to look for a port:

# sbofind nethack
SBo:    nethack 3.6.6
Path:   /usr/sbo/repo/games/nethack
    
SBo:    unnethack 5.2.0
Path:   /usr/sbo/repo/games/unnethack

Install a port

We will install the previously searched port: nethack

# sboinstall nethack
Nethack is a single-player dungeon exploration game. The emphasis is
on discovering the detail of the dungeon. Each game presents a
different landscape - the random number generator provides an
essentially unlimited number of variations of the dungeon and its
denizens to be discovered by the player in one of a number of
characters: you can pick your race, your role, and your gender.
    
User accounts that play this need to be members of the "games" group.
    
Proceed with nethack? [y] y
nethack added to install queue.

Install queue: nethack

Are you sure you wish to continue? [y] y
[... compilation ... ]
+==============================================================================
| Installing new package /tmp/nethack-3.6.6-x86_64-1_SBo.tgz
+==============================================================================
    
Verifying package nethack-3.6.6-x86_64-1_SBo.tgz.
Installing package nethack-3.6.6-x86_64-1_SBo.tgz:
PACKAGE DESCRIPTION:
# nethack (roguelike game)
#
# Nethack is a single-player dungeon exploration game. The emphasis is
# on discovering the detail of the dungeon. Each game presents a
# different landscape - the random number generator provides an
# essentially unlimited number of variations of the dungeon and its
# denizens to be discovered by the player in one of a number of
# characters: you can pick your race, your role, and your gender.
#
# http://nethack.org
#
Package nethack-3.6.6-x86_64-1_SBo.tgz installed.
Cleaning for nethack-3.6.6...

Done, nethack is installed! sboinstall manages dependencies and if required will ask you for every required other slackbuilds to install to add to the queue before starting compiling.

Example: getting flatpak

Flatpak is a software distribution system for linux distributions, mainly to provide desktop software that could be complicated to package like Libreoffice, GIMP, Microsoft Teams etc… Using Slackware, this can be a good source of software.

To use flatpak and the official flathub repository, we need to install flatpak first. It’s now as easy as:

# sboinstall flatpak

And answer yes to questions (you will be asked to agree for every dependency required, there are a few of them), if you don’t want to answer, you can use -r flag to automatically accept.

We need to add the official repository flathub using the following command:

# flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

And now you can browse flatpak programs on flathub

For example, if you want to install VLC

# flatpak install flathub org.videolan.VLC

You will be prompted about all the dependencies required in order to get VLC installed, those dependencies are some system parts that will be shared across all the flatpak software in order to efficiently use disk space. For VLC, some kde components will be required and also Xorg GL/VAAPI/openh264 environments, flatpak manage all this and you don’t have to worry about this.

The file /usr/sbo/repo/desktop/flatpak/README explains quirks of flatpak on Slackware, like pulseaudio instructions or the polkit policy on slackware not allowing your user to use the global flatpak install command.

I found the following ~/.xinitrc to enable dbus and pulseaudio for me, so flatpak programs work.

start-pulseaudio-x11
eval $(pax11publish -i)
dbus-run-session fvwm2

About the offline laptop project

Written by Solène, on 10 November 2020.
Tags: #life #disconnected

Comments on Fediverse/Mastodon

Third article of the offline laptop serie.

Sometimes, network access is required

Having a totally disconnected system isn’t really practical for a few reasons. Sometimes, I really need to connect the offline laptop to the network. I do produce some content on the computer, so I need to do backups. The easiest way for me to have reliable backup is to host them on a remote server holding the data, this requires network connection for the time of the backup. Of course, backups could be done on external disks or usb memory sticks (I don’t need to backup much), but I never liked this backup solution; don’t get me wrong, I don’t say it’s ineffective, but it doesn’t suit my needs.

Besides the backup, I may need to sync files like my music files. I may have bought new music that I want to get on the offline laptop, so network access is required.

I also require internet access to install new packages or upgrade the system, this isn’t a regular need but I occasionnaly require a new program I forgot to install. This could be solved by downloaded the whole packages repository but this would require too many disk space for packages I would never use. This would also waste a lot of network transfer.

Finally, when I work on my blog, I need to publish the files, I use rsync to sync the destination directory from my local computer and this requires access to the Internet through ssh.

A nice place at the right time

The moments I enjoy using this computer the most is by taking the laptop on a table with nothing around me. I can then focus about what I am doing. I find comfortable setups being source of distraction, so a stool and a table are very nice in my opinion.

In addition to have a clean place to use it, I like to dedicate some time for the use of this computer. I can write texts or some code in a given time frame.

On a computer with 24/7 power and internet access I always feel everything is at reach, then I tend to slack with it.

Having a rather limited battery life changes the way I experience the computer use. It has a finite time, I have N minutes until the computer has to be charged or shutdown. This produces for me the same effect than when starting watching a movie, sometimes I pick up a movie that fits the time I can spend on it.

Knowing I have some time until the computer stops, I know I must keep focused because time is passing.

Keyboard tweaks to use Xorg on an IBook laptop

Written by Solène, on 09 November 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

Simple article for posterity or future-me. I will share here my tweaks to make the IBook G4 laptop (apple keyboard) suitable for OpenBSD , this should work for Linux too as long as you run X.

Command should be alt+gr

I really need the alt+gr key which is not there on the keyboard, I solved this by using this line in my ~/.xsession.

xmodmap -e "keycode 115 = ISO_Level3_Shift"

i3 and mod4

As the touchpad is incredibely bad by nowadays standards (and it only has 1 button and no scrolling feature!), I am using a window manager that could be entirely keyboard driven, while I’m not familiar with tiling window manager, i3 was easy to understand and light enough. Long time readers may remember I am familiar with stumpwm but it’s not really a dynamic tiling window manager, I can only tolerate i3 using the tabs mode.

But an issue arise, there are no “super” key on the keyboard, and using “alt” would collide with way too many programs. One solution is to use “caps lock” as a “super” key.

I added this in my ~/.xsession file:

xmodmap ~/.Xmodmap

with ~/.Xmodmap having the following instructions:

clear Lock 
keycode 66 = Hyper_L
add mod4 = Hyper_L
clear Lock

This will disable to “toggling” effect of caps lock, and will turn it into a “Super” key that will be refered as mod4 for i3.

Connect to Mastodon using HTTP 1.0 with Brutaldon

Written by Solène, on 09 November 2020.
Tags: #openbsd #mastodon

Comments on Fediverse/Mastodon

Today post is about Brutaldon, a Mastodon/Pleroma interface in old fashion HTML like in the web 1.0 era. I will explain how it works and how to install it. Tested and approved on an 16 years old powerpc laptop, using Mastodon with w3m or dillo web browsers!

Introduction

Brutaldon is a mastodon client running as a web server. This mean you have to connect to a running brutaldon server, you can use a public one like Brutaldon.online and then you will have two ways to connect to your account:

  1. using oauth which will redirect through a dedicated API page of your mastodon instance and will give back a token once you logged in properly, this is totally safe of use, but requires javascript to be enabled to works due to the login page on the instance
  2. there is “old login” method in which you have to provide your instance address, your account login and password. This is not really safe because the brutaldon instance will known about your credentials, but you can use any web browser with that. There are not much security issues if you use a local brutaldon instance

How to install it

The installation is quite easy, I wish this could be as easy more often. You need a python3 interpreter and pipenv. If you don’t have pipenv, you need pip to install pipenv. On OpenBSD this would translates as:

$ pip3.8 install --user pipenv

Note that on some system, pip3.8 could be pip3, or pip. Due to the coexistence of python2 and python3 for some time until we can get ride of python2, most python related commands have a suffix to tell which python version it uses.

If you install pipenv with pip, the path will be ~/.local/bin/pipenv.

Now, very easy to proceed! Clone the code, run pipenv to get the dependencies, create a sqlite database and run the server.

$ git clone git://github.com/jfmcbrayer/brutaldon.git
$ cd brutaldon
$ pipenv install
$ pipenv run python ./manage.py migrate
$ pipenv run python ./manage.py runserver

And voilà! Your brutaldon instance is available on http://localhost:8000, you only need to open it on your web browser and log-in to your instance.

As explained in the INSTALL.md file of the project, this method isn’t suitable for a public deployment. The code is a Django webapp and could be used with wsgi and a proper web server. This setup is beyond the scope of this article.

Join the peer to peer social network Scuttlebutt using OpenBSD and Oasis

Written by Solène, on 04 November 2020.
Tags: #openbsd #ssb

Comments on Fediverse/Mastodon

In this article I will tell you about the Scuttlebutt social network, what makes it special and how to join it using OpenBSD. From here, I’ll refer to Scuttlebutt as SSB.

Introduction to the protocol

You can find all the related documentation on the official website. I will make a simplification of the protocol to present it.

SSB is decentralized, meaning there are no central server with clients around it (think about Twitter model) nor it has a constellation of servers federating to each others (Fediverse: mastodon, plemora, peertube…). SSB uses a peer to peer model, meaning nodes exchanges data between others nodes. A device with an account is a node, someone using SSB acts as a node.

The protocol requires people to be mutual followers to make the private messaging system to work (messages are encrypted end-to end).

This peer to peer paradigm has specific implications:

  1. Internet is not required for SSB to work. You could use it with other people in a local network. For example, you could visit a friend’s place exchange your SSB data over their network.
  2. Nodes owns the data: when you join, this can be very long to download the content of nodes close to you (relatively to people you follow) because the SSB client will download the data, and then serves everything locally. This mean you can use SSB while being offline, but also that in the case seen previously at your friend’s place, you can exchange data from mutual friends. Example: if A visits B, B receives A updates. When you visit B, you will receive B updates but also A updates if you follow B on the network.
  3. Data are immutables: when you publish something on the network, it will be spread across nodes and you can’t modify those data. This is important to think twice before publishing.
  4. Moderation: there are no moderation as there are no autority in control, but people can block nodes they don’t want to get data from and this blocking will be published, so other people can easily see who gets blocked and block it too. It seems to work, I don’t have opinion about this.
  5. You discover parts of the network by following people, giving you access to the people they follow. This makes the discovery of the network quite organic and should create some communities by itself. Birds of feather flock together!
  6. It’s complicated to share an account across multiples devices because you need to share all your data between the devices, most people use an account per device.

SSB clients

There are differents clients, the top clients I found were:

There are also lot of applications using the protocol, you can find a list on this link. One particularly interesting project is git-ssb, hosting a git repository on the network.

Most of the code related to SSB is written in NodeJS.

In my opinion, Patchwork is the most user-friendly client but Oasis is very nice too. Patchwork has more features, like being able to publish pictures within your messages which is not currently possible with Oasis.

Manyverse works fine but is rather limited in term of features.

The developer community working on the projects seems rather small and would be happy to receive some help.

How to install Oasis on OpenBSD

I’ve been able to get the Oasis client to run on OpenBSD. The NodeJS ecosystem is quite hostile to anything non linux but following the path of qbit (who solved few libs years ago), this piece of software works.

$ doas pkg_add libvips git node autoconf--%2.69 automake--%1.16 libtool
$ git clone https://github.com/fraction/oasis
$ cd oasis
$ env AUTOMAKE_VERSION=1.16 AUTOCONF_VERSION=2.69 CC=clang CXX=clang++ npm install --only=prod

There is currently ONE issue that require a hack to start Oasis. The lo0 interface must not have any IPv6 address.

You can use the following command as root to remove the IPv6 addresses.

# ifconfig lo0 -inet6

I reported this bug as I’ve not been able to fix it myself.

How to use Oasis on OpenBSD

2023–10–21 THIS IS OUTDATED: oasis seems to be unmaintained, and I can’t get it to work anymore even on Linux.

When you want to use Oasis, you have to run

$ node /path/to/oasis_sources

You can add --help to have the usage output, like --offline if you don’t want oasis to do networking.

When you start oasis, you can then open http://localhost:3000 to access network. Beware that this address is available to anyone having access to your system.

You have to use an invitation from someone to connect to a node and start following people to increase your range in this small world.

You can use a public server which acts as a 24/7 node to connect people together on https://github.com/ssbc/ssb-server/wiki/Pub-Servers.

How to backup your account

You absolutely need to backup your ~/.ssb/ directory if you don’t want to lose your account. There are no central server able to help you recover your account in case of data lass.

If you want to use another client on another computer, you have to copy this directory to the new place.

I don’t think the whole directory is required, but I have not been able to find more precise information.

How the OpenBSD -stable packages are built

Written by Solène, on 29 October 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

In this long blog post, I will write about the technical details of the OpenBSD stable packages building infrastructure. I have setup the infrastructure with the help of Theo De Raadt who provided me the hardware in summer 2019, since then, OpenBSD users can upgrade their packages using pkg_add -u for critical updates that has been backported by the contributors. Many thanks to them, without their work there would be no packages to build. Thanks to pea@ who is my backup for operating this infrastructure in case something happens to me.

The total lines of code used is around 110 lines of shell.

Original design

In the original design, the process was the following. It was done separately on each machine (amd64, arm64, i386, sparc64).

Updating ports

First step is to update the ports tree using cvs up from a cron job and capture its output. If there is a result, the process continues into the next steps and we discard the result.

With CVS being per-directory and not using a database like git or svn, it is not possible to “poll” for an update except by verifying every directory if a new version of files is available. This check is done three time a day.

Make a list of ports to compile

This step is the most complicated of the process and weights for a third of the total lines of code.

The script uses cvs rdiff between the cvs release and stable branches to show what changed since release, and its output is passed through a few grep and awk scripts to only retrieve the “pkgpaths” (the pkgpath of curl is net/curl) of the packages that were updated since the last release.

From this raw output of cvs rdiff:

File ports/net/dhcpcd/Makefile changed from revision 1.80 to 1.80.2.1
File ports/net/dhcpcd/distinfo changed from revision 1.48 to 1.48.2.1
File ports/net/dnsdist/Makefile changed from revision 1.19 to 1.19.2.1
File ports/net/dnsdist/distinfo changed from revision 1.7 to 1.7.2.1
File ports/net/icinga/core2/Makefile changed from revision 1.104 to 1.104.2.1
File ports/net/icinga/core2/distinfo changed from revision 1.40 to 1.40.2.1
File ports/net/synapse/Makefile changed from revision 1.13 to 1.13.2.1
File ports/net/synapse/distinfo changed from revision 1.11 to 1.11.2.1
File ports/net/synapse/pkg/PLIST changed from revision 1.10 to 1.10.2.1

The script will produce:

net/dhcpcd
net/dnsdist
net/icinga/core2
net/synapse

From here, for each pkgpath we have sorted out, the sqlports database is queried to get the full list of pkgpaths of each packages, this will include all packages like flavors, subpackages and multipackages.

This is important because an update in editors/vim pkgpath will trigger this long list of packages:

editors/vim,-lang
editors/vim,-main
editors/vim,gtk2
editors/vim,gtk2,-lang
[...40 results hidden for readability...]
editors/vim,no_x11,ruby
editors/vim,no_x11,ruby,-lang
editors/vim,no_x11,ruby,-main

Once we gathered all the pkgpaths to build and stored them in a file, next step can start.

Preparing the environment

As the compilation is done on the real system (using PORTS_PRIVSEP though) and not in a chroot we need to clean all packages installed except the minimum required for the build infrastructure, which are rsync and sqlports.

dpb(1) can’t be used because it didn’t gave good results for building the delta of the packages between release and stable.

The various temporary directories used by the ports infrastructure are cleaned to be sure the build starts in a clean environment.

Compiling and creating the packages

This step is really simple. The ports infrastructure is used to build the packages list we produced at step 2.

env SUBDIRLIST=package_list BULK=yes make package

In the script there is some code to manage the logs of the previous batch but there is nothing more.

Every new run of the process will pass over all the packages which received a commit, but the ports infrastructure is smart enough to avoid rebuilding ports which already have a package with the correct version.

Transfer the package to the signing team

Once the packages are built, we need to pass only the built packages to the person who will manually sign the packages before publishing them and have the mirrors to sync.

From the package list, the package file lists are generated and reused by rsync to only copy the packages generated.

env SUBDIRLIST=package_list show=PKGNAMES make | grep -v "^=" | \
      grep ^. | tr ' ' '\n' | sed 's,$,\.tgz,' | sort -u

The system has all the -release packages in ${PACKAGE_REPOSITORY}/${MACHINE_ARCH}/all/ (like /usr/ports/packages/amd64/all) to avoid rebuilding all dependencies required for building a package update, thus we can’t copy all the packages from the directory where the packages are moved after compilation.

Send a notification

Last step is to send an email with the output of rsync to send an email telling which machine built which package to tell the people signing the packages that some packages are available.

As this process is done on each machine and that they don’t necessarily build the same packages (no firefox on sparc64) and they don’t build at the same speed (arm64 is slower), mails from the four machines could arrive at very different time, which led to a small design change.

The whole process is automatic from building to delivering the packages for signature. The signature step requires a human to be done though, but this is the price for security and privilege separation.

Current design

In the original design, all the servers were running their separate cron job, updating their own cvs ports tree and doing a very long cvs diff. The result was working but not very practical for the people signing who were receiving mails from each machine for each batch.

The new design only changed one thing: One machine was chosen to run the cron job, produce the package list and then will copy that list to the other machines which update their ports tree and run the build. Once all machines finished to build, the initiator machine will gather outputs and send an unique mail with a summary of each machine. This became easier to compare the output of each architecture and once you receive the email this means every machine finished their job and the signing can be done.

Having the summary of all the building machines resulted in another improvement: In the logic of the script, it is possible to send an email telling absolutely no package has been built while the process was triggered, which means, something went wrong. From here, I need to check the logs to understand why the last commit didn’t produce a package. This can be failures like a distinfo file update forgotten in the commit.

Also, this permitted fixing one issue: As the distfiles are shared through a common NFS mount point, if multiples machines try to fetch a distfile at the same time, both will fail to build. Now, the initiator machine will download all the required distfiles before starting the build on every node.

All of the previous scripts were reused, except the one sending the email which had to be rewritten.

Port of the week: rclone

Written by Solène, on 28 October 2020.
Tags: #portoftheweek

Comments on Fediverse/Mastodon

New Port of the Week after 3 years! I never thought it was so long since last blog post about slrn.

This post is about the awesome rclone program, written in Go and available on most popular platforms (including OpenBSD!). I will explain how to configure it from the interactive command, from file and what you can do with rclone.

rclone can be see as a rsync on steroids which supports lot of Cloud backend and also support creating an encrypted data repository over any backend (local file, ftp, sftp, webdav, Dropbox, AWS S3, etc…).

It’s not a automatic synchronization tool or a backup software. It can copy files from A to B, synchronize two places (can be harmful if you don’t pay attention).

Let’s see how to use it with an ssh server on which we will create an encrypted repository to store important data.

Official documentation

Installation

Most of the time, run your package manager to install rclone. It’s a single binary.

Interactive configuration

You can skip this LONG section if you want to learn what rclone can do and how to configure it in a 10 lines files.

There is a parameter to have a question / answer interface to configure your repository, using rclone config.

I’ll make a full walkthrough to enable an encrypted repository because I struggled to understand the logic behind rclone when I started using it.

Let’s start. I’ll create an encrypted destination on my local NAS which doesn’t have full disk encryption, so anyone who access the system won’t be able to read my data. First, this will require to set up an sftp repository and then an encrypted repository using the previous one as a backend.

Let’s create a new config named home_nas.

$ rclone config
2020/10/27 21:30:48 NOTICE: Config file "/home/solene/.config/rclone/rclone.conf" not found - using defaults
No remotes found - make a new one
n) New remote
s) Set configuration password
q) Quit config
n/s/q> n
name> home_nas

We want the storage type 29, “SSH/SFTP” (I removed all 50+ others storages for readability).

Type of storage to configure.
Enter a string value. Press Enter for the default ("").
Choose a number from below, or type in your own value
[...]
29 / SSH/SFTP Connection
   \ "sftp"
[...]
Storage> 29

My host is 192.168.1.200

** See help for sftp backend at: https://rclone.org/sftp/ **
    
SSH host to connect to
Enter a string value. Press Enter for the default ("").
Choose a number from below, or type in your own value
 1 / Connect to example.com
   \ "example.com"
host> 192.168.1.200

I will connect with the username solene.

SSH username, leave blank for current username, solene
Enter a string value. Press Enter for the default ("").
user> solene

Standard port 22, which is the default

SSH port, leave blank to use default (22)
Enter a string value. Press Enter for the default ("").
port> 

I answer n because I want rclone to use ssh agent, this could be the ssh password to the remote user, but I highly discourage everyone from using password authentication on SSH!

SSH password, leave blank to use ssh-agent.
y) Yes type in my own password
g) Generate random password
n) No leave this optional password blank (default)
y/g/n> n

Leave this except if you want to provide a private key.

Raw PEM-encoded private key, If specified, will override key_file parameter.
Enter a string value. Press Enter for the default ("").
key_pem> 

Leave this except if you want to provide a PEM-encoded private key.

Path to PEM-encoded private key file, leave blank or set key-use-agent to use ssh-agent.
    
Leading `~` will be expanded in the file name as will environment variables such as `${RCLONE_CONFIG_DIR}`.
    
Enter a string value. Press Enter for the default ("").
key_file> 

Leave this except if you need to use a password to unlock your private key. I use ssh agent so I don’t need it.

The passphrase to decrypt the PEM-encoded private key file.
    
Only PEM encrypted key files (old OpenSSH format) are supported. Encrypted keys
in the new OpenSSH format can't be used.
y) Yes type in my own password
g) Generate random password
n) No leave this optional password blank (default)
y/g/n> n

If your user agent manage multiples keys, you should enter the correct value here, I only have one key so I leave it empty.

When set forces the usage of the ssh-agent.
    
When key-file is also set, the ".pub" file of the specified key-file is read and only the associated key is
requested from the ssh-agent. This allows to avoid `Too many authentication failures for *username*` errors
when the ssh-agent contains many keys.
Enter a boolean value (true or false). Press Enter for the default ("false").
key_use_agent> 

This is a question about crypto, accept the default except if you have to connect to old servers.

Enable the use of insecure ciphers and key exchange methods. 
    
This enables the use of the following insecure ciphers and key exchange methods:
    
- aes128-cbc
- aes192-cbc
- aes256-cbc
- 3des-cbc
- diffie-hellman-group-exchange-sha256
- diffie-hellman-group-exchange-sha1
    
Those algorithms are insecure and may allow plaintext data to be recovered by an attacker.
Enter a boolean value (true or false). Press Enter for the default ("false").
Choose a number from below, or type in your own value
 1 / Use default Cipher list.
   \ "false"
 2 / Enables the use of the aes128-cbc cipher and diffie-hellman-group-exchange-sha256, diffie-hellman-group-exchange-sha1 key exchange.
   \ "true"
use_insecure_cipher> 

We want to keep hashcheck feature so just skip the answer to keep the default value.

Disable the execution of SSH commands to determine if remote file hashing is available.
Leave blank or set to false to enable hashing (recommended), set to true to disable hashing.
Enter a boolean value (true or false). Press Enter for the default ("false").
disable_hashcheck> 

We are at the end of the configuration, we are proposed to change more parameters but we don’t need to.

Edit advanced config? (y/n)
y) Yes
n) No (default)
y/n> n

Now we can see the output of the configuration file of rclone in regards to my home_nas destination. I agree with the configuration to continue.

Remote config
--------------------
[home_nas]
type = sftp
host = 192.168.1.200
user = solene
--------------------
y) Yes this is OK (default)
e) Edit this remote
d) Delete this remote
y/e/d> y

Here is a summary of the configuration, we have only one remote here.

Current remotes:
    
Name                 Type
====                 ====
home_nas             sftp

In the menu, I will choose to add another remote. Let’s name it home_nas_encrypted

e) Edit existing remote
n) New remote
d) Delete remote
r) Rename remote
c) Copy remote
s) Set configuration password
q) Quit config
e/n/d/r/c/s/q> n
name> home_nas_encrypted

We will choose the special storage crypt which work on an existing backend.

Type of storage to configure.
Enter a string value. Press Enter for the default ("").
Choose a number from below, or type in your own value
10 / Encrypt/Decrypt a remote
   \ "crypt"
Storage> 10

To this question, we will define we want the data stored to home_nas_encrypted being saved in home_nas remote in the encrypted_repo directory.

** See help for crypt backend at: https://rclone.org/crypt/ **
    
Remote to encrypt/decrypt.
Normally should contain a ':' and a path, eg "myremote:path/to/dir",
"myremote:bucket" or maybe "myremote:" (not recommended).
Enter a string value. Press Enter for the default ("").
remote> home_nas:encrypted_repo

Depending on the level of obfuscation your choice may vary. The simple filename obfuscation is fine for me.

How to encrypt the filenames.
Enter a string value. Press Enter for the default ("standard").
Choose a number from below, or type in your own value
 1 / Encrypt the filenames see the docs for the details.
   \ "standard"
 2 / Very simple filename obfuscation.
   \ "obfuscate"
 3 / Don't encrypt the file names.  Adds a ".bin" extension only.
   \ "off"
filename_encryption> 2

As for the directory names obfuscation, I recommend to enable it, otherwise that leave the whole directory tree readable!

Option to either encrypt directory names or leave them intact.
    
NB If filename_encryption is "off" then this option will do nothing.
Enter a boolean value (true or false). Press Enter for the default ("true").
Choose a number from below, or type in your own value
 1 / Encrypt directory names.
   \ "true"
 2 / Don't encrypt directory names, leave them intact.
   \ "false"
directory_name_encryption> 1

Type the password that will be used to encrypt the data.

Password or pass phrase for encryption.
y) Yes type in my own password
g) Generate random password
y/g> y
Enter the password:
password:
Confirm the password:
password:

You can add a salt to the passphrase, I choose not too.

Password or pass phrase for salt. Optional but recommended.
Should be different to the previous password.
y) Yes type in my own password
g) Generate random password
n) No leave this optional password blank (default)
y/g/n> 

No need to change advanced parameters.

Edit advanced config? (y/n)
y) Yes
n) No (default)
y/n> n

Here is a summary of the configuration of this remote backend. I’m fine with it.

Remote config
--------------------
[home_nas_encrypted]
type = crypt
remote = home_nas:encrypted_repo
directory_name_encryption = true
password = *** ENCRYPTED ***
--------------------
y) Yes this is OK (default)
e) Edit this remote
d) Delete this remote
y/e/d> y

We see we have now two remote backends, one with the crypt type.

Current remotes:
    
Name                 Type
====                 ====
home_nas             sftp
home_nas_encrypted   crypt

Quit rclone, the configuration is done.

e) Edit existing remote
n) New remote
d) Delete remote
r) Rename remote
c) Copy remote
s) Set configuration password
q) Quit config
e/n/d/r/c/s/q> q

Configuration file

The previous configuration process only produced this short configuration file, so you may copy/paste from it and adapt to add more backends if you want, instead of doing the tedious config process.

Here is my file ~/.config/rclone/rclone.conf on my desktop.

[home_nas]
type = sftp
host = 192.168.1.200
user = solene
    
[home_nas_encrypted]
type = crypt
remote = home_nas:encrypted_repo
directory_name_encryption = true
password = GDS9B1B1LrBa3ltQrSbLf1Vq5C6VbaA1AJVlSZ8

First usage

Now we defined our configuration, we need to create the remote directory that will be used as a backend, this is important to avoid errors when using rclone, this is a simple step required only once.

$ rclone mkdir home_nas_encrypted:

On the remote server, I can see a /home/solene/encryted_repo directory. It’s now ready to use!

A few commands

rclone has a LOT of commands available, I will present a few of them.

Copying files to/from backend

Let’s say I want to copy files to the encrypted repository. There is a copy command.

$ rclone copy /home/solene/log/templates home_nas_encrypted:blog_template  

There are no output by default when the program runs fine. You can use -v flag to have some verbose output (I prefer it).

List files on a remote backend

Now, we want to see if the files were copied correctly, we will use the ls command.

$ rclone ls home_nas_encrypted:
      299 blog_template/article.tpl
      700 blog_template/gopher_head.tpl
     2505 blog_template/layout.tpl
      295 blog_template/more.tpl
      236 blog_template/navigation.tpl
       57 blog_template/one-tag.tpl
       34 blog_template/page.tpl
      189 blog_template/rss-item.tpl
      326 blog_template/rss.tpl

We can also use ncdu to mimic the ncdu program displaying a curses interfaces to visualize disk usage in a nice browsing tree.

$ rclone ncdu home_nas_encrypted
-- home_nas_encrypted: ------------------
  6.379k [##########] /blog_template

The sync command

Files and directories can also be copied with the sync command, but this must be used with care because it makes sure the destination matches exactly the origin when you use it. It’s the equivalent of rsync -a --delete origin/ destination/, so any extra files will be removed! Note that you can use --dry-run to see what will happen.

Filters

When you copy files using the various available method, instead of using a path, you can provide a filter file or a list of paths to transfers. This can be very efficient when you want to recover specifics data.

The documentation about filtering is available here

Parameters

rclone supports a lot of parameters, like to limit upload bandwidth, copy multiples files at once, enable an interactive mode in case of file deletion/overwriting.

Mount

On Linux, FreeBSD and MacOS, rclone can use a FUSE filesystem to mount the remote repository on the filesystem, making its uses totally transparent.

This is extremely useful, avoiding the tediousness of the get/put paradigm of rclone.

This can even be used to make an encrypted repository on the local filesystem! :)

Create a webdav/sftp/ftp server

rclone has the capability of act as a server and expose a configured remote backend on various network protocol like webdav, sftp, ftp, s3 (minio) !

The serv document is available here

Example running a simple webdav server with hardcoded login/password:

$ rclone serv webdav --user solene --password ANicePassword home_nas_encrypted:

OpenVPN as the default gateway on OpenBSD

Written by Solène, on 27 October 2020.
Tags: #openbsd #openvpn

Comments on Fediverse/Mastodon

If you plan to use an OpenVPN tunnel to reach your default gateway, which would make the tun interface in the egress group, and use tun0 in your pf.conf which is loaded before OpenVPN starts?

Here are the few tips I use to solve the problems.

Remove your current default gateway

We don’t want a default gateway on the system. You need to know the remote address of the VPN server.

If you have a /etc/mygate file, remove it.

The /etc/hostname.if file (with if being your interface name, like em0 for example), should look like this:

192.168.1.200
up
!route add -host A.B.C.D 192.168.1.254
  • First line is the IP on my lan
  • Second line is to make the interface up.
  • Third line is means you want to reach A.B.C.D via 192.168.1.254, with the IP A.B.C.D being the remote VPN server.

Create the tun0 interface at boot

Create a /etc/hostname.tun0 file with only up as content, that will create tun0 at boot and make it available to pf.conf and you prevent it from loading the configuration.

You may think one could use “egress” instead of the interface name, but this is not allowed in queuing.

Don’t let OpenVPN manage the route

Don’t use redirect-gateway def1 bypass-dhcp from the OpenVPN configuration, this will create a route which is not default and so the tun0 interface won’t be in the egress group, which is not something we want.

Add those two lines in your configuration file, to execute a script once the tunnel is established, in which we will make the default route.

script-security 2
up /etc/openvpn/script_up.sh

In /etc/openvpn/script_up.sh you simply have to write

#!/bin/sh
/sbin/route add -net default X.Y.Z.A

If you have IPv6 connectivity, you have to add this line:

/sbin/route add -inet6 2000::/3 fe80::%tun0

(not sure it’s 100% correct for IPv6 but it works fine for me! If it’s wrong, please tell me how to make it better).

A curated non-violent games list

Written by Solène, on 18 October 2020.
Tags: #gaming

Comments on Fediverse/Mastodon

For long time I wanted to share a list of non-violent games I enjoyed, so here it is. Obviously, this list is FAR from being complete and exhaustive. It contains games I played and that I liked. They should all run on Linux and some on OpenBSD.

Aside this list, most tycoon and puzzle games should be non-violent.

Automation / Building games

This game is like Factorio, you have to automate production lines and increase the output of shapes/colors. Very time consuming.

The project is Open source but you need to buy the game if you don’t want to compile yourself. Or just use my compiled version working in a web browser.

Play shapez.io in web browser

A transport tycoon game, multiplayer possible! Very complex, the community is active and you can find tons of mods.

The game is Open source and you can certainly install it on any distribution with the package manager.

This game is about building equipment to restore the nature into a wasteland, improve the biodiversity and then remove all your structures.

The game is not open source but is free of charge. The music seems to be under an open licence. Still, you can pay what you want for it to support the developer.

This is a short game about chaining producing buildings into another, all from garbage up to some secret ending :)

The game is not open source but is free of charge.

Sandbox / Adventure game

This game is a clone of Minecraft, it supports a lot of mods (which can make the game very complex, like adding trains tracks with their signals, the pinnacle of complexity :D). As far as I know, the game now supports health but there are no fight involved.

The game is Open source and free of charge.

This game is about exploration in a forest. It has a nice music, gameplay is easy.

The game is not open source but it’s free. Still, you can pay what you want for it to support the developer.

Action / reflex games

This category of games contains games that require some reflexes or at least need to player to be active to play.

This game is about driving a 2D motocross and pass through obstacles, it can be very hard and will challenge you for long time.

it’s Open source and free of charge.

This is a fun game where you need to drive some big trucks only using a displayed control panel with your mouse which make things very hard.

The game is not open source and not free, but the cost isn’t very high (3.99€ at the moment from France).

This game is about a teenager character who is on vacation in a place with no cell network, and you will have to make a hike and meet people to go to the end. Very relaxing :)

The game isn’t open source and isn’t free, but costs around 8€ at the moment from France.

This game is about adding trains to tracks and avoid them to crash. I found this game to be more about reflexes than building, simulation or tycoon. You mostly need to route the trains in real time.

The game isn’t open source and not free but costs around 10€.

This game is a 2D platform game with interesting gameplay mechanics, it is surprisingly full of good ideas and a very nice music :) The characters are very cute and the whole environment looking great.

The game isn’t open source and not free.

Simulation

This game may not be liked by everyone, it consists at driving a truck in Europe and pick up a cargo to deliver it someone else, taking care of not hurting it and driving safely by respecting the law. You can also buy garages and hire people to drive trucks for you to make money. The game is relaxing and also pretty accurate in the environment. I have been driving in many European countries and this game really reflects country signs, cars, speed limits, country side etc… Some cities received more work and you can see monuments from the road. The game doesn’t cost much and works on Linux although it’s not open source.

This game is hard and will require learning. The goal is to create rockets to send astronauts in space, or even land on a planet or an asteroid, and come back. Doing a whole trip like this requires some knowledge about the game mechanics and physics. This game is certainly not for everyone if you want to achieve something, I never made better than just sending a rocket in space and let it crash on the planet after lacking fuel or drifting in space forever… The game works on Linux, requires an average computer and can be obtained at a very fair price like 10€ when it’s on sales (which happens very often). Definitely a must to play if you like space.

Puzzle games (Zachtronics games)

What’s a Zachtronics game? It’s a game edited by Zachtronics! Every game from this studio have a common pattern. You solve puzzles with more and more complexes systems, you can compare your result in speed / efficiency / steps to the others player. They are a mix in between automation and puzzles. Those games are really good. There are more than the 3 games I list, but I didn’t enjoy them all, check the full list

You play an alchemist who is asked to create product for a rich family. You need to setup devices to transforms and combine materials into the expected result.

The game isn’t open source and isn’t free. The average cost is 20€.

This game is in 3D, you receive materials on conveyor belts and you will have to rotate and wield them to deliver the expect material.

The game isn’t open source and isn’t free. The average cost is 20€.

This game is about writing code into assembly. There are calculations units that will add/sub values from registers and pass it to another unit. Even more fun if you print the old fashion instructions book!

The game isn’t open source and isn’t free. The average cost is 10€.

Visual Novel

The expression Amrilato

This game is about a Japanese girl who ends in a parallel world where everything seems similar but in this Japan, people talk Esperanto.

The game isn’t open source and isn’t free. The average cost is 20€.

Not very violent

Way of the Passive Fist

I would like to add this game to this list. It’s a brawler (like street of rage) in which you don’t fight people, but you only dodge attacks to exhaust enemies or counter-attack. It’s still a bit violent because it involves violence toward you, and throwing back a knife would still be violent… But still, I think this is an unique game that merits to be better known. :)

The game isn’t open source and isn’t free, expect around 15€ for it.

Making a home NAS using NixOS

Written by Solène, on 18 October 2020.
Tags: #nixos #linux #nas

Comments on Fediverse/Mastodon

Still playing with NixOS, I wanted to experience how difficult it would be to write a NixOS configuration file to turn a computer into a simple NAS with basics features: samba storage, dlna server and auto suspend/resume.

What is NixOS? As a reminder for some and introduction to the others, NixOS is a Linux distribution built by the Nix package manager, which make it very different than any other operating system out there, except Guix which has a similar approach with their own package manager written in Scheme.

NixOS uses a declarative configuration approach along with lot of others features derived from Nix. What’s big here is you no longer tweak anything in /etc or install packages, you can define the working state of the system in one configuration file. This system is a totally different beast than the others OS and require some time to understand how it work. Good news though, everything is documented in the man page configuration.nix, from fstab configuration to users managements or how to enable samba!

Here is the /etc/nixos/configuration.nix file on my NAS.

It enables ssh server, samba, minidlna and vnstat. Set up a user with my ssh public key. Ready to work.

Using rtcwake command (Linux specific), it’s possible to put the system into standby mode and schedule an auto resume after some time. This is triggered by a cron job at 01h00.

{ config, pkgs, ... }:
{
  # include stuff related to hardware, auto generated at install
  imports = [ ./hardware-configuration.nix ];
  boot.loader.grub.device = "/dev/sda";
      
  # network configuration
  networking.interfaces.enp3s0.ipv4.addresses = [ {
    address = "192.168.42.150";
    prefixLength = 24;
  } ];
  networking.defaultGateway = "192.168.42.1";
  networking.nameservers = [ "192.168.42.231" ];
      
  # FR locales and layout
  i18n.defaultLocale = "fr_FR.UTF-8";
  console = { font = "Lat2-Terminus16"; keyMap = "fr"; };
  time.timeZone = "Europe/Paris";
      
  # Packages management
  environment.systemPackages = with pkgs; [
    kakoune vnstat borgbackup utillinux
  ];
      
  # network disabled (I need to check the ports used first)
  networking.firewall.enable = false;
      
  # services to enable
  services.openssh.enable = true;
  services.vnstat.enable = true;
      
  # auto standby
  services.cron.systemCronJobs = [
      "0 1 * * * root rtcwake -m mem --date +6h"
  ]; 
      
  # samba service
  services.samba.enable = true;
  services.samba.enableNmbd = true;
  services.samba.extraConfig = ''
        workgroup = WORKGROUP
        server string = Samba Server
        server role = standalone server
        log file = /var/log/samba/smbd.%m
        max log size = 50
        dns proxy = no
        map to guest = Bad User
    '';
  services.samba.shares = {
      public = {
          path = "/home/public";
          browseable = "yes";
          "writable" = "yes";
          "guest ok" = "yes";
          "public" = "yes";
          "force user" = "share";
        };
     };
      
  # minidlna service
  services.minidlna.enable = true;
  services.minidlna.announceInterval = 60;
  services.minidlna.friendlyName = "Rorqual";
  services.minidlna.mediaDirs = ["A,/home/public/Musique/" "V,/home/public/Videos/"];
      
  # trick to create a directory with proper ownership
  # note that tmpfiles are not necesserarly temporary if you don't
  # set an expire time. Trick given on irc by someone I forgot the name..
  systemd.tmpfiles.rules = [ "d /home/public 0755 share users" ];
      
  # create my user, with sudo right and my public ssh key
  users.users.solene = {
    isNormalUser = true;
    extraGroups = [ "wheel" "sudo" ];
    openssh.authorizedKeys.keys = [
          "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOIZKLFQXVM15viQXHYRjGqE4LLfvETMkjjgSz0mzMzS personal"
          "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOIZKLFQXVM15vAQXBYRjGqE6L1fvETMkjjgSz0mxMzS pro"
    ];
  };
      
  # create a dedicated user for the shares
  # I prefer a dedicated one than "nobody"
  # can't log into it
  users.users.share= {
    isNormalUser = false;
  };
}

NixOS optional features in packages

Written by Solène, on 14 October 2020.
Tags: #nixos #linux #nix

Comments on Fediverse/Mastodon

As a claws-mail user, I like to have calendar support in the mail client to be able to “accept” invitations. In the default NixOS claws-mail package, the vcalendar module isn’t installed with the package. Still, it is possible to add support for the vcalendar module without ugly hack.

It turns out, by default, the claws-mail package in Nixpkg has an optional build option for the vcalendar module, we need to tell nixpkg we want this module and claws-mail will be compiled.

As stated in the NixOS manual, the optionals features can’t be searched yet. So what’s possible is to search for your package in the NixOS packages search, click on the package name to get to the details and click on the link named “Nix expression” that will open a link to the package definition on GitHUB, claws-mail nix expression

As you can see on the claws-mail nix expression code, there are lot of lines with optional, those are features we can enable. Here is a sample:

[..]
++ optional (!enablePluginArchive) "--disable-archive-plugin"
++ optional (!enablePluginLitehtmlViewer) "--disable-litehtml_viewer-plugin"
++ optional (!enablePluginPdf) "--disable-pdf_viewer-plugin"
++ optional (!enablePluginPython) "--disable-python-plugin"
[..]

In your configuration.nix file, where you define the package list you want, you can tell you want to enable the plugin vcalendar, this is done as in the following example:

environment.systemPackages = with pkgs; [
  kakoune git firefox irssi minetest
  (pkgs.claws-mail.override { enablePluginVcalendar = true;})
];

When you rebuild your system to match the configuration definition, claws-mail will be compiled with the extras options you defined.

Now, I have claws-mail with vCalendar support.

Unlock a full disk encryption NixOS with usb memory stick

Written by Solène, on 06 October 2020.
Tags: #nixos #linux

Comments on Fediverse/Mastodon

Using NixOS on a laptop on which the keyboard isn’t detected when I need to type the password to decrypt disk, I had to find a solution. This problem is hardware related, not Linux or NixOS related.

I highly recommend using full disk encryption on every computer following a thief threat model. Having your computer stolen is bad, but if the thief has access to all your data, you will certainly be in trouble.

This was time to find how to use an usb memory stick to unlock the full disk encryption in case I don’t have my hands on an usb keyboard to unlock the computer.

There are 4 steps to enable unlocking the luks volume using a device.

  1. Create the key
  2. Add the key on the luks volume
  3. Write the key on the usb device
  4. Configure NixOS

First step, creating the file. The easiest way is to the following:

# dd if=/dev/urandom of=/root/key.bin bs=4096 count=1

This will create a 4096 bytes key. You can choose the size you want.

Second step is to register that key in the luks volume, you will be prompted for luks password when doing so.

# cryptsetup luksAddKey /dev/sda1 /root/key.bin

Then, it’s time to write the key to your usb device, I assume it will be /dev/sdb.

# dd if=/root/key.bin of=/dev/sdb bs=4096 count=1

And finally, you will need to configure NixOS to give the information about the key. It’s important to give the correct size of the key. Don’t forget to adapt "crypted" to your luks volume name.

boot.initrd.luks.devices."crypted".keyFileSize = 4096;
boot.initrd.luks.devices."crypted".keyFile = "/dev/sdb";

Rebuild your system with nixos-rebuild switch and voilà!

Going further

I recommend using the fallback to password feature so if you lose or don’t have your memory stick, you can type the password to unlock the disk. Note that you need to not put anything looking like a /dev/sdb because if it exists and no key are there, the system won’t ask for password, and you will need to reboot.

boot.initrd.luks.devices."crypted".fallbackToPassword = true;

It’s also possible to write the key in a partition or at a specific offset into your memory disk. For this, look at boot.initrd.luks.devices."volume".keyFileOffset entry.

Playing chess by email

Written by Solène, on 28 September 2020.
Tags: #chess

Comments on Fediverse/Mastodon

It’s possible to play chess using email. This is possible because there are notations like PGN (Portable Game Notation) that describe the state of a game.

By playing on your computer and sending the PGN of the game to your opponent, that person will be able to play their move and send you the new PGN so you can play.

Using xboard

This is quite easy with xboard (which should be available in most bsd/linux/unix distributions), as long as you are aware of the few keybindings.

When you start a game, press Ctrl+E to enter edition mode, this will prevent the AI to play, then make your move.

From there, you can press Ctrl+C to copy the state of the game. You will have something like this in your clipboard.

[Event "Edited game"]
[Site "solene.local"]
[Date "2020.09.28"]
[Round "-"]
[White "-"]
[Black "-"]
[Result "*"]
    
1. d3
*

You can send this to your opponent, but the only needed data is 1. d3 which is the PGN notation of the moves. You can throw the rest.

In a more advanced game, you will end up mailing this kind of data:

1. d3 e6 2. e4 f5 3. exf5 exf5 4. Qe2+ Be7 5. Qxe7+ Qxe7+

When you want to play your turn, load that line and press Ctrl+V, you should see the moves happening on the board.

Using gnuchess

gnuchess allow playing chess in command line.

When you want to start a game, you will have a prompt, type manual to not play against the AI. I recommend using coords to display coordinates on the axis of the board.

When you type show board you will have this display:

  white  KQkq
    
8 r n b q k b n r 
7 p p p p p p p p 
6 . . . . . . . . 
5 . . . . . . . . 
4 . . . . . . . . 
3 . . . . . . . . 
2 P P P P P P P P 
1 R N B Q K B N R 
  a b c d e f g h 

Then, I can type d3 I get a display

8 r n b q k b n r 
7 p p p p p p p p 
6 . . . . . . . . 
5 . . . . . . . . 
4 . . . . . . . . 
3 . . . P . . . . 
2 P P P . P P P P 
1 R N B Q K B N R 
  a b c d e f g h 

From the game, you can save the game using pgnsave FILE and load a game using pgnload FILE.

You can see the list of the moves using show game.

About pipelining OpenBSD ports contributions

Written by Solène, on 27 September 2020.
Tags: #openbsd #automation

Comments on Fediverse/Mastodon

After modest contributions to the NixOS operating system which made me learn about the contribution process, I found enjoyable to have an automatic report and feedback about the quality of the submitted work. While on NixOS this requires GitHub, I think this could be applied as well on OpenBSD and the mailing list contributing system.

I made a prototype before starting the real work and actually I’m happy with the result.

This is what I get after feeding the script with a mail containing a patch:

Determining package path         ✓	
Verifying patch isn't committed  ✓	
Applying the patch               ✓	
Fetching distfiles               ✓	
Distfile checksum                ✓	
Applying ports patches           ✓	
Extracting sources               ✓	
Building result                  ✓

It requires a lot of checks to find a patch in the file, because we have have patches generated from cvs or git which have a slightly different output. And then, we need to find from where to apply this patch.

The idea would be to retrieve mails sent to ports@openbsd.org by subscribing, then store metadata about that submission into a database:

Sender
Date
Diff (raw text)
Status (already committed, doesn't apply, apply, compile)

Then, another program will pick a diff from the database, prepare a VM using a derivated qcow2 disk from a base image so it always start fresh and clean and ready, and do the checks within the VM.

Once it is finished, a mail could be sent as a reply to the original mail to give the status of each step until error or last check. The database could be reused to make a web page to track what compiles but is not yet committed. As it’s possible to verify if a patch is committed in the tree, this can automatically prune committed patches over time.

I really think this can improve tracking patches sent to ports@ and ease the contribution process.

DISCLAIMER

  • This would not be an official part of the project, I do it on my own
  • This may be cancelled
  • This may be a bad idea
  • This could be used “as a service” instead of pulling automatically from ports, meaning people could send mails to it to receive an automatic review. Ideally this should be done in portcheck(1) but I’m not sure how to verify a diff apply on the ports tree without enforcing requirements
  • Human work will still be required to check the content and verify the port works correctly!

Docker cheatsheet

Written by Solène, on 24 September 2020.
Tags: #docker

Comments on Fediverse/Mastodon

Simple Docker cheatsheet. This is a short introduction about Docker usage and common questions I have been asking myself about Docker.

The official documentation for building docker images can be found here

Build an image

Building an image is really easy. As a requirement, you need to be in a directory that can contain data you will use for building the image but most importantly, you need a Dockerfile file.

The Dockerfile file hold all the instructions to create the container. A simple example would be this description:

FROM busybox
CMD "echo" "hello world"

This will create a docker container using busybox base image and run echo "hello world" when you run it.

To create the container, use the following command in the same directory in which Dockerfile is:

$ docker build -t your-image-name .

Advanced image building

If you need to compile sources to distribute a working binary, you need to prepare the environment to have the required dependencies to compile and then you need to compile a static binary to ship the container without all the dependencies.

In the following example we will use a debian environment to build the software downloaded by git.

FROM debian as work
WORKDIR /project

RUN apt-get update
RUN apt-get install -y git make gcc
RUN git clone git://bitreich.org/sacc /project
RUN apt-get install -y libncurses5-dev libncurses5
RUN make LDFLAGS="-static -lncurses -ltinfo"

FROM debian

COPY --from=work /project/sacc /usr/local/bin/sacc

CMD "sacc" "gopherproject.org"

I won’t explain every command here, but you may see that I have split the packages installation in two commands. This was to help debugging.

The trick here is that the docker build process has a cache feature. Every time you use a FROM, COPY, RUN or CMD docker will cache the current state of the build process, if you re-run the process docker will be able to pick up the most recent state until the change.

I wasn’t sure how to compile statically the software at first, and having to install git make and gcc and run git clone EVERY TIME was very time consuming and bandwidth consuming.

In case you run this build and it fails, you can re-run the build and docker will catch up directly at the last working step.

If you change a line, docker will reuse the last state with a FROM/COPY/RUN/CMD command before the changed line. Knowing about this is really important for more efficient cache use.

Run an image

With the previously locally built image we can run it with the command:

$ docker run your-image-name
hello world

By default, when you use an image name to run, if you don’t have a local image that match the name docker will check on the docker official repository if an image exists, if so, it will be pulled and run.

$ docker run hello-world

This is a sample official container that will display some explanations about docker.

If you want to try a gopher client, I made a docker version of it that you can run with the following command:

$ docker run -t -i rapennesolene/sacc

Why did you require -t and -i parameters? The former is to tell docker you want a tty because it will manipulate a terminal and the latter is to ask an interactive session.

Persistant data

By default, every data of the docker container get wiped out once it stops, which may be really undesirable if you use docker to deploy a service that has a state and require an installation, configuration files etc…

Docker has two ways to solve it:

1) map a local directory 2) map a docker volume name

This is done with the parameter -v with the docker run command.

$ docker run -v data:/var/www/html/ nextcloud

This will map a persistent storage named “data” on the host on the path /var/www/html in the docker instance. By using data, docker will check if /var/lib/docker/volumes/data exists, if so it will reuse it and if not it will create it.

This is a convenient way to name volumes and let docker manage it.

The other way is to map a local path to a container environment path.

$ docker run -v /home/nextcloud:/var/www/html nextcloud

In this case, the directory /home/nextcloud on the host and /var/www/html in the docker environment will be the same directory.

A few tips about the cd command

Written by Solène, on 04 September 2020.
Tags: #unix

Comments on Fediverse/Mastodon

While everyone familiar with a shell know about the command cd there are a few tips you should know.

Moving to your $HOME directory

$ pwd
/tmp
$ cd
$ pwd
/home/solene

Using cd without argument will change your current directory to your $HOME.

Moving into someone $HOME directory

While this should fail most of the time because people shouldn’t allow anyone to visit their $HOME, there are use case it can be used though.

$ cd ~user1
$ pwd
/home/user1
$ cd ~solene
$ pwd
/home/solene

Using ~user as a parameter will move to that user $HOME directory, note that cd and cd ~youruser have the same result.

Moving to previous directory

This is a very useful command which allow going back and forth between two directories.

$ pwd
/home/solene
$ cd /tmp
$ pwd
/tmp
$ cd -
/home/solene
$ pwd
/home/solene

When you use cd - the command will move to the previous directory in which you were. There are two special variables in your shell: PWD and OLDPWD, when you move somewhere, OLDPWD will hold your current location before moving and then PWD hold the new path. When you use cd - the two variables get exchanged, this mean you can only jump from two paths using cd - multiple times.

Please note that when using cd - your new location is displayed.

Changing directory by modifying current PWD

thfr@ showed me a cd feature I never heard about, and it’s the perfect place to write about it. Note that this work in ksh and zsh but is reported to not work in bash.

One example will explain better than any text.

$ pwd
/tmp/pobj/foobar-1.2.0/work
$ cd 1.2.0 2.4.0
/tmp/pobj/foobar-2.4.0/work

This tells cd to replace first parameter pattern by the second parameter in the current PWD and then cd into it.

$ pwd
/home/solene
$ cd solene user1
/home/user1

This could be done in a bloated way with the following command:

$ cd $(echo $PWD | sed "s/solene/user1/")

I learned it a few minutes ago but I see a lot of uses cases where I could use it.

Moving into the current directory after removal

In some specific case, like having your shell into a directory that existed but was deleted and removed (this happens often when you working into compilation directories).

A simple trick is to tell cd to go to the current location.

$ cd .

or

$ cd $PWD

And cd will go into the same path and you can start hacking again in that directory.

Find which package provides a given file in OpenBSD

Written by Solène, on 04 September 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

There is one very handy package on OpenBSD named pkglocatedb which provides the command pkglocate.

If you need to find a file or binary/program and you don’t know which package contains it, use pkglocate.

$ pkglocate */bin/exiftool  
p5-Image-ExifTool-12.00:graphics/p5-Image-ExifTool:/usr/local/bin/exiftool

With the result, I know that the package p5-Image-ExifTool will provide me the command exiftool.

Another example looking for files containing the pattern “libc++”

$ pkglocate libc++
base67:/usr/lib/libc++.so.5.0
base67:/usr/lib/libc++abi.so.3.0
comp67:/usr/lib/libc++.a
comp67:/usr/lib/libc++_p.a
comp67:/usr/lib/libc++abi.a
comp67:/usr/lib/libc++abi_p.a
qt4-4.8.7p23:x11/qt4,-main:/usr/local/lib/qt4/mkspecs/unsupported/macx-clang-libc++/
qt4-4.8.7p23:x11/qt4,-main:/usr/local/lib/qt4/mkspecs/unsupported/macx-clang-libc++/Info.plist.app
qt4-4.8.7p23:x11/qt4,-main:/usr/local/lib/qt4/mkspecs/unsupported/macx-clang-libc++/Info.plist.lib
qt4-4.8.7p23:x11/qt4,-main:/usr/local/lib/qt4/mkspecs/unsupported/macx-clang-libc++/qmake.conf
qt4-4.8.7p23:x11/qt4,-main:/usr/local/lib/qt4/mkspecs/unsupported/macx-clang-libc++/qplatformdefs.h
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++-32/
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++-32/qmake.conf
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++-32/qplatformdefs.h
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++/
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++/qmake.conf
qtbase-5.13.2p0:x11/qt5/qtbase,-main:/usr/local/lib/qt5/mkspecs/linux-clang-libc++/qplatformdefs.h

As you can see, base sets are also in the database used by pkglocate, so you can easily find if a file is from a set (that you should have) or if the file comes from a package.

Find which package installed a file

Klemmens Nanni (kn@) told me it’s possible to find which package installed a file present in the filesystem using pkg_info command which comes from the base system. This can be handy to know from which package an installed file comes from, without requiring pkglocatedb.

$ pkg_info -E /usr/local/bin/convert
/usr/local/bin/convert: ImageMagick-6.9.10.86p0
ImageMagick-6.9.10.86p0 image processing tools

This tells me convert binary was installed by ImageMagick package.

Download files listed in a http index with wget

Written by Solène, on 16 June 2020.
Tags: #wget #internet

Comments on Fediverse/Mastodon

Sometimes I need to download files through http from a list on an “autoindex” page and it’s always painful to find a correct command for this.

The easy solution is wget but you need to use the correct parameters because wget has a lot of mirroring options but you only want specific ones to achieve this goal.

I ended up with the following command:

wget --continue --accept "*.tgz" --no-directories --no-parent --recursive http://ftp.fr.openbsd.org/pub/OpenBSD/6.7/amd64/

This will download every tgz files available at the address given as last parameter.

The parameters given will filter to only download the tgz files, put the files in the current working directory and most important, don’t try to escape to the parent directory to start downloading again. The `–continue`` parameter allow to interrupt wget and start again, downloaded file will be skipped and partially downloaded files will be completed.

Do not reuse this command if files changed on the remote server because continue feature only work if your local file and the remote file are the same, this simply look at the local and remote names and will ask the remote server to start downloading at the current byte range of your local file. If meanwhile the remote file changed, you will have a mix of the old and new file.

Obviously ftp protocol would be better suited for this download job but ftp is less and less available so I find wget to be a nice workaround for this.

Birthday dates management using calendar

Written by Solène, on 15 June 2020.
Tags: #openbsd #plaintext #automation

Comments on Fediverse/Mastodon

I manage my birthday list so I don’t forget about them in a calendar file so I can use it in scripts

The calendar file format is easy but sadly it only works using English month names.

This is an example file with differents spacing:

7  August	This is 7 august birthday!
 8 August	This is 8 august birthday!
16 August	This is 16 august birthday!

Now you have a calendar file you can use the calendar binary on it and show incoming events in the next n days using -A flag.

calendar -A 20

Note that the default file is ~/.calendar/calendar so if you use this file you don’t need to use the -f flag in calendar.

Now, I also use it in crontab with xmessage to show a popup once a day with incoming birthdays.

30 13 * * *  calendar -A 7 -f ~/.calendar/birthday | grep . && calendar -A 7 -f ~/.calendar/birthdays | env DISPLAY=:0 xmessage -file -

You have to set the DISPLAY variable so it appear on the screen.

It’s important to check if calendar will have any output before calling xmessage to prevent having an empty window.

prose - Blogging with email

Written by Solène, on 11 June 2020.
Tags: #blog #email #blog #plaintext

Comments on Fediverse/Mastodon

The software developer prx, his website is available at https://ybad.name/ (en/fr), released a new software called prose to publish a blog by sending emails.

I really like this idea, while this doesn’t suit my needs at all, I wanted to write about it.

The code can be downloaded from this address https://dev.ybad.name/prose/ .

I will briefly introduce how it works but the README file is well explaining, prose must be started from the mail server, upon email receival in /etc/mail/aliases the email will be piped into prose which will produce the html output.

On the security side, prose doesn’t use any external command and on OpenBSD it will use unveil and pledge features to reduce privileges of prose, unveil will restrict the process file system accesses outside of the html output directory.

I would also congrats prx who demonstrates again that writing good software isn’t exclusive to IT professionnal.

Gaming on OpenBSD

Written by Solène, on 05 June 2020.
Tags: #openbsd #gaming

Comments on Fediverse/Mastodon

While no one would expect this, there are huge efforts from a small team to bring more games into OpenBSD. In fact, now some commercial games works natively now, thanks to Mono or Java. There are no wine or linux emulation layer in OpenBSD.

Here is a small list of most well known games that run on OpenBSD:

  • Northguard (RTS)
  • Darksburg (RTS)
  • Dead Cells (Side scroller action game)
  • Stardew Valley (Farming / Roguelike)
  • Slay The Spire (Card / Roguelike)
  • Axiom Verge (Side scroller, metroidvania)
  • Crosscode (top view twin stick shooter)
  • Terraria (Side scroller action game with craft)
  • Ion Fury (FPS)
  • Doom 3 (FPS)
  • Minecraft (Sandbox - not working using latest version)
  • Tales Of Maj’Eyal (Roguelike with lot of things in it - open source and free)

I would also like to feature the recently made compatible games from Zachtronics developer, those are ingenious puzzles games requiring efficiency. There are games involving Assembly code, pseudo code, molecules etc…

  • Opus Magnum
  • Exapunks
  • Molek-Syntez

Finally, there are good RPG running thanks to devoted developer spending their free time working on game engine reimplementation:

  • Elder Scroll III: Morrowind (openmw engine)
  • Baldur’s Gate 1 and 2 (gemrb engine)
  • Planescape: Torment (gemrb engine)

There is a Peertube (opensource decentralized Youtube alternative) channel where I started publishing gaming videos recorded from OpenBSD. Now there are also videos from others people that are published. OpenBSD Gaming channel

The full list of running games is available in the Shopping guide webpage including information how they run, on which store you can buy them and if they are compatible.

Big thanks to thfr@ who works hard to keep the shopping guide up to date and who made most of this possible. Many thanks to all the other people in the OpenBSD Gaming community :)

All these efforts are important for software conservation over time.

Beautiful background pictures on OpenBSD

Written by Solène, on 20 May 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

While the title may appear quite strange, the article is about installing a package to have a new random wallpaper everytime you start the X session!

First, you need to install a package named openbsd-backgrounds which is quite large with a size of 144 MB. This package made by Marc Espie contains lot of pictures shot by some OpenBSD developers.

You can automatically set a picture as a background when xenodm start and prompt for your username by uncommenting a few lines in the file /etc/X11/xenodm/Xsetup_0:

Uncomment this part

if test -x /usr/local/bin/openbsd-wallpaper
then
/usr/local/bin/openbsd-wallpaper
fi

The command openbsd-wallpaper will display a different random picture on every screen (if you have multiples screen connected) every time you run it.

Communauté OpenBSD française

Written by Solène, on 17 May 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

This article is exceptionnaly in French because it’s about a French OpenBSD community.

Bonjour à toutes et à tous.

Exceptionnellement je publie un billet en français sur mon blog car je tiens à faire passer le mot concernant la communauté française obsd4a.

Vous pourrez par exemple trouver la quasi intégralité de la FAQ OpenBSD traduite à cette adresse

Sur l’accueil du site vous pourrez trouver des liens vers le forum, le wiki, le blog, la mailing list et aussi les informations pour rejoindre le salon irc (#obsd4* sur freenode)

https://openbsd.fr.eu.org/

New blog feature: Fediverse comments

Written by Solène, on 16 May 2020.
Tags: #fediverse #automation

Comments on Fediverse/Mastodon

I added a new feature to my blog today, when I post a new blog article this will trigger my dedicated Mastodon user https://bsd.network/@solenepercent to publish a Toot so people can discuss the content there.

Every article now contains a link to the toot if you want to discuss about an article.

This is not perfect but a good trade-off I think:

  1. the website remains static and light (nothing is included, only one more link per blog post)
  2. people who would like to discuss about it can proceed in a known place instead of writing reactions on reddit or other places without a chance for me to asnwer
  3. this is not relying on proprietary services

Of course, if you want to give me feedback, I’m still happy to reply to emails or on IRC.

FreeBSD 12.1 on a laptop

Written by Solène, on 11 May 2020.
Tags: #freebsd #mate #laptop

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Introduction

I’m using FreeBSD again on a laptop for some reasons so expect to read more about FreeBSD here. This tutorial explain how to get a graphical desktop using FreeBSD 12.1.

I used a Lenovo Thinkpad T480 for this tutorial.

Intel graphics hardware support

If you have a recent Intel integrated graphic card (maybe less than 3 years), you have to install a package containing the driver:

pkg install drm-kmod

and you also have to tell the system the correct path of the module (because another i915kms.ko file exist):

sysrc kld_list="/boot/modules/i915kms.ko"

Choose your desktop environnement

Install Xfce

pkg install xfce

Then in your user ~/.xsession file you must append:

exec ck-launch-session startxfce4

Install MATE

pkg install mate

Then in your user ~/.xsession file you must append:

exec ck-launch-session mate-session

Install KDE5

pkg install kde5

Then in your user ~/.xsession file you must append:

exec ck-launch-session startplasma-x11

Setting up the graphical interface

You have to enable a few services to have a working graphical session:

  • moused to get laptop mouse support
  • dbus for hald
  • hald for hardware detection
  • xdm for display manager where you log-in

You can install them with the command:

pkg install xorg dbus hal xdm

Then you can enable the services at boot using the following commands, order is important:

sysrc moused_enable="yes"
sysrc dbus_enable="yes"
sysrc hald_enable="yes"
sysrc xdm_enable="yes"

Reboot or start the services in the same order:

service moused start
service dbus start
service hald start
service xdm start

Note that xdm will be in qwerty layout.

Power management

The installer should have prompted for the service powerd, if you didn’t activate it at this time, you can still enable it.

Check if it’s running

service powerd status

Enabling

sysrc powerd_enable="yes"

Starting the service

service powerd start

Webcam support

If you have a webcam and want to use it, some configuration is required in order to make it work.

Install the package webcamd, it will displays all the instructions written below at the install step.

pkg install webcamd

From here, append this line to the file /boot/loader.conf to load webcam support at boot time:

cuse_load="yes"

Add your user to the webcamd group so it will be able to use the device:

pw groupmod webcamd -m YOUR_USER

Enable webcamd at boot:

sysrc webcamd_enable="yes"

Now, you have to logout from your user for the group change to take place. And if you want the webcamd daemon to work now and not wait next reboot:

kldload cuse
service webcamd start
service devd restart

You should have a /dev/video0 device now. You can test it easily with the package pwcview.

External resources

I found this blog very interesting, I wish I found it before I struggle with all the configuration as it explains how to install FreeBSD on the exact same laptop. The author explains how to make a transparent lagg0 interface for switching from ethernet to wifi automatically with a failover pseudo device.

https://genneko.github.io/playing-with-bsd/hardware/freebsd-on-thinkpad-t480/

Enable dark mode on Firefox

Written by Solène, on 04 May 2020.
Tags: #firefox

Comments on Fediverse/Mastodon

Some websites (like this one) now offers two differents themes: light and dark.

Dark themes are proven to be better for the eyes and reduce battery usage on mobiles devices because it requires less light to be displayed hence it requires less energy to display. The gain is optimal on OLED devices but it also works on classic LCD screens.

While on Windows and MacOS there is a global setting for the user interface in which you choose if your system is in light or dark mode, with that setting being used by lot of applications supporting dark/light themes, on Linux and BSDs (and others) operating systems there is no such settings and your web browser will keep displaying the light theme all the time.

Hopefully, it can be fixed in firefox as as explained in the documentation.

To make it short, in the about:config special Firefox page, one can create a new key ui.systemUsesDarkTheme with a number value of 1, the firefox about:config page should turn dark immediately and then Firefox will try to use dark themes when they are available.

You should note that as explained in the mozilla documentation, if you have the key privacy.resistFingerprinting set to true the dark mode can’t be used. It seems dark mode and privacy can’t belong together for some reasons.

Many thanks to https://tilde.zone/@andinus who pointed me this out after I overlooked that page and searched a long time with no result how to make Firefox display website using the dark theme.

Aggregate internet links with mlvpn

Written by Solène, on 28 March 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

In this article I’ll explain how to aggregate internet access bandwidth using mlvpn software. I struggled a lot to set this up so I wanted to share a how-to.

Pre-requisites

mlvpn is meant to be used with DSL / fiber links, not wireless or 4G links with variable bandwidth or packet loss.

mlvpn requires to be run on a server which will be the public internet access and on the client on which you want to aggregate the links, this is like doing multiples VPN to the same remote server with a VPN per link, and aggregate them.

Multi-wan roundrobin / load balancer doesn’t allow to stack bandwidth but doesn’t require a remote server, depend on what you want to do, this may be enough and mlvpn may not be required.

mlvpn should be OS agnostic between client / server but I only tried between two OpenBSD hosts, your setup may differ.

Some network diagram

Here is a simple network, the client has access to 2 ISP through two ethernet interfaces.

em0 and em1 will have to be on different rdomains (it’s a feature to separate routing tables).

Let’s say the public ip of the server is 1.2.3.4.

                [internet]
                    ↑
                    | (public ip on em0)
             #-------------#
             |             |
             |   Server    |
             |             |
             #-------------#
                |       |
                |       |
                |       |
                |       |
    (internet)  |       | (internet)
    #-------------#   #-------------#
    |             |   |             |
    |   ISP 1     |   |  ISP 2      |
    |             |   |             |  (you certainly don't control those)
    #-------------#   #-------------#
                |       |
                |       |
  (dsl1 via em0)|       | (dsl1 via em1)
             #-------------#
             |             |
             |   Client    |
             |             |
             #-------------#

Network configuration

As said previously, em0 and em1 must be on different rdomains, it can easily be done by adding rdomain 1 and rdomain 2 to the interfaces configuration.

Example in /etc/hostname.em0

rdomain 1
dhcp

mlvpn installation

On OpenBSD the installation is as easy as pkg_add mlvpn (should work starting from 6.7 because it required patching).

mlvpn configuration

Once the network configuration is done on the client, there are 3 steps to do to get aggregation working:

  1. mlvpn configuration on the server
  2. mlvpn configuration on the client
  3. activating NAT on the client

Server configuration

On the server we will use the UDP ports 5080 et 5081.

Connections speed must be defined in bytes to allow mlvpn to correctly balance the traffic over the links, this is really important.

The line bandwidth_upload = 1468006 is the maximum download bandwidth of the client on the specified link in bytes. If you have a download speed of 1.4 MB/s then you can choose a value of 1.4*1024*1024 => 1468006.

The line bandwidth_download = 102400 is the maximum upload bandwidth of the client on the specified link in bytes. If you have an upload speed of 100 kB/s then you can choose a value of 100*1024 => 102400.

The password line must be a very long random string, it’s a shared secret between the client and the server.

# config you don't need to change
[general]
statuscommand = "/etc/mlvpn/mlvpn_updown.sh"
protocol = "tcp"
loglevel = 4
mode = "server"
tuntap = "tun"
interface_name = "tun0"
cleartext_data = 0
ip4 = "10.44.43.2/30"
ip4_gateway = "10.44.43.1"
    
# things you need to change
password = "apoziecxjvpoxkvpzeoirjdskpoezroizepzdlpojfoiezjrzanzaoinzoi"
    
[dsl1]
bindhost = "1.2.3.4"
bindport = 5080
bandwidth_upload = 1468006
bandwidth_download = 102400
    
[dsl2]
bindhost = "1.2.3.4"
bindport = 5081
bandwidth_upload = 1468006
bandwidth_download = 102400

Client configuration

The password value must match the one on the server, the values of ip4 and ip4_gateway must be reversed compared to the server configuration (this is so in the following example).

The bindfib lines must correspond to the according rdomain values of your interfaces.

# config you don't need to change
[general]
statuscommand = "/etc/mlvpn/mlvpn_updown.sh"
loglevel = 4
mode = "client"
tuntap = "tun"
interface_name = "tun0"
ip4 = "10.44.43.1/30"
ip4_gateway = "10.44.43.2"
timeout = 30
cleartext_data = 0
    
password = "apoziecxjvpoxkvpzeoirjdskpoezroizepzdlpojfoiezjrzanzaoinzoi"
    
[dsl1]
remotehost = "1.2.3.4"
remoteport = 5080
bindfib = 1
    
[dsl2]
remotehost = "1.2.3.4"
remoteport = 5081
bindfib = 2

NAT configuration (server side)

As with every VPN you must enable packet forwarding and create a pf rule for the NAT.

Enable forwarding

Add this line in /etc/sysctl.conf:

net.inet.ip.forwarding=1

You can enable it now with sysctl net.inet.ip.forwarding=1 instead of waiting for a reboot.

In pf.conf you must allow the UDP ports 5080 and 5081 on the public interface and enable nat, this can be done with the following lines in pf.conf but you should obviously adapt to your configuration.

# allow NAT on VPN
pass in on tun0
pass out quick on em0 from 10.44.43.0/30 to any nat-to em0
    
# allow mlvpn to be reachable
pass in on egress inet proto udp from any to (egress) port 5080:5081

Start mlvpn

On both server and client you can run mlvpn with rcctl:

rcctl enable mlvpn
rcctl start mlvpn

You should see a new tun0 device on both systems and being able to ping them through tun0.

Now, on the client you have to add a default gateway through the mlvpn tunnel with the command route add -net default 10.44.43.2 (adapt if you use others addresses). I still didn’t find how to automatize it properly.

Your client should now use both WAN links and being visible with the remote server public IP address.

mlvpn can be used for more links, you only need to add new sections. mlvpn also support IPv6 but I didn’t take time to find how to make it work, si if you are comfortable with ipv6 it may be easy to set up IPv6 with the variables ip6 and ip6_gateway in mlvpn.conf.

OpenBSD -current - Frequently Asked Questions

Written by Solène, on 27 March 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

Hello, as there are so many questions about OpenBSD -current on IRC, Mastodon or reddit I’m writing this FAQ in hope it will help people.

The official FAQ already contains answers about -current like Following -current and using snapshots and Building the system from sources.

What is OpenBSD -current?

OpenBSD -current is the development version of OpenBSD. Lot of people use it for everyday tasks.

How to install OpenBSD -current?

OpenBSD -current refers to the last version built from sources obtained with CVS, however, it’s also possible to get a pre-built system (a snapshot) usually built and pushed on mirrors every 1 or 2 days.

You can install OpenBSD -current by getting an installation media like usual, but on the path /pub/OpenBSD/snapshots/ on the mirror.

How do I upgrade from -release to -current?

There are two ways to do so:

  1. Download bsd.rd file from the snapshots directory and boot it to upgrade like for a -release to -release upgrade
  2. Run sysupgrade -s command as root, this will basically download all sets under /home/_sysupgrade and boot on bsd.rd with an autoinstall(8) config.

How do I upgrade my -current snapshot to a newer snapshot?

Exactly the same process as going from -release to -current.

Can I downgrade to a -release if I switch to -current?

No.

What issues can I expect in OpenBSD -current?

There are a few issues possibles that one can expect

Out of sync packages

If a library get updated into the base system and you want to update packages, they won’t be installable until packages are rebuilt with that new library, this usually takes 1 up to 3 days.

This only create issues in case you want to install a package you don’t have.

The other way around, you can have an old snapshot and packages are not installable because the libraries linked to by the packages are newer than what is available in your system, in this case you have to upgrade snapshot.

Snapshots sets are getting updated on the mirror

If you download the sets on the mirror to update your -current version, you may have an issue with the sha256 sum, this is because the mirror is getting updated and the sha256 file is the first to be transferred, so sets you are downloading are not the one the sha256 will compare.

Unexpected system breakage

Sometimes, very rarely (maybe 2 or 3 time in a year?), some snapshots are borked and will prevent system to boot or lead to regularly crashes. In that case, it’s important to report the issue with the sendbug utility.

You can fix this by using an older snapshot from this archives server and prevent this to happen by reading bugs@ mailing list before updating.

Broken package

Sometimes, a package update will break it or break some others packages, this is often quickly fixed on popular packages but in some niche packages you may be the only one using it on -current and the only one who can report about it.

If you find breakage on something you use, it may be a good idea to report the problem on ports@openbsd.org mailing list if nobody did before. By doing so, the issue will be fixed and next -release users will be able to install a working package.

Is -current stable enough for a server or a workstation?

It’s really up to you. Developers are all using -current and are forbidden to break it, so the system should totally be usable for everyday use.

What may be complicated on a server is keep updating it regularly and face issues requires troubleshooting (like major database upgrade which was missing a quirk).

For a workstation I think it’s pretty safe as long as you can deal with packages that can’t be installed until they are in sync.

Advice for working remotely from home

Written by Solène, on 17 March 2020.
Tags: #life

Comments on Fediverse/Mastodon

Hello,

A few days ago, as someone working remotely since 3 years I published some tips to help new remote workers to feel more confident into their new workplace: home

I’ve been told I should publish it on my blog so it’s easier to share the information, so here it is.

  • dedicate some space to your work area, if you use a laptop try to dedicate a table corner for it, so you don’t have to remove your “work station” all the time

  • keep track of the time, remember to drink and stand up / walk every hour, you can set an alarm every hour to remember or use software like http://www.workrave.org/ or https://github.com/hovancik/stretchly which are very useful. If you are alone at home, you may lose track of time so this is important.

  • don’t forget to keep your phone at hand if you use it for communication with colleagues. Think that they may only know your phone number, so it’s their only way to reach you

  • keep some routine for lunch, you should eat correctly and take the time to do so, avoid eating in front of the computer

  • don’t work too much after work hours, do like at your workplace, leave work when you feel it’s time to and shutdown everything related to work, it’s a common trap to want to do more and keep an eye on mails, don’t fall into it.

  • depending on your social skills, work field and colleagues, speak with others (phone, text whatever), it’s important to keep social links.

Here are some others tips from Jason Robinson

  • after work, distance yourself from the work time by taking a short walk outside, cooking, doing laundry, or anything that gets you away from the work area and cuts the flow.

  • take at least one walk outside if possible during the day time to get fresh air.

  • get a desk that can be adjusted for both standing and sitting.

I hope those advices will help you going through the crisis, take care of yourselves.

A day as an OpenBSD developer

Written by Solène, on 19 February 2020.
Tags: #life #openbsd

Comments on Fediverse/Mastodon

This is a little story that happened a few days ago, it explains well how I usually get involved into ports in OpenBSD.

1 - Lurking into ports/graphics/

At first, I was looking in various ports there are in the graphics category, searching for an image editor that would run correctly on my offline laptop. Grafx2 is laggy when using the zoom mode and GIMP won’t run, so I just open ports randomly to read their pkg/DESCR file.

This way, I often find gems I reuse later, sometimes I have less luck and I only tried 20 ports which are useless to me. It happens I find issues in ports looking randomly like this…

2 - Find the port « comix »

Then, the second or third port I look at is « comix », here is the DESCR file.

Comix is a user-friendly, customizable image viewer. It is specifically
designed to handle comic books, but also serves as a generic viewer. It
reads images in ZIP, RAR or tar archives (also gzip or bzip2 compressed)
as well as plain image files.

That looked awesome, I have lot of books as PDF I want to read but it’s not convenient in a “normal” PDF reader, so maybe comix would help!

3 - Using comix

Once comix was compiled (a mix of python and gtk), I start it and I get errors opening PDFs… I start it again from console, and in the output I get the explanation that PDF files are not usable in comix.

Then I read about the CBZ or CBT files, they are archives (zip or tar) containing pictures, definitely not what a PDF is.

4 - mcomix > comix

After a few searches on the Internet, I find that comix last release is from 2009 and it never supported PDF, so nothing wrong here, but I also found comix had a fork named mcomix.

mcomix forked a long time ago from comix to fix issues and add support for new features (like PDF support), while last release is from 2016, it works and still receive commits (last is from late 2019). I’m going for using comix!

5 - Installing mcomix from ports

Best way to install a program on OpenBSD is to make a port, so it’s correctly packaged, can be deinstalled and submit to ports@ mailing list later.

I did copy comix folder into mcomix, use a brain dead sed command to replace all occurrence of comix by mcomix, and it mostly worked! I won’t explain little details, but I got mcomix to work within a few minutes and I was quite happy! Fun fact is that comix port Makefile was mentioning mcomix as a suggestion for upgrade.

6 - Enjoying a CBR reader

With mcomix installed, I was able to read some PDF, it was a good experience and I was pretty happy with it. I’ve spent a few hours reading, a few moments after mcomix was installed.

7 - mcomix works but not all the time

After reading 2 longs PDFs, I got issues with the third, some pages were not rendered and not displayed. After digging this issue a bit, I found about mcomix internals. Reading PDF is done by rendering every page of the PDF using mutool binary from mupdf software, this is quite CPU intensive, and for some reason in mcomix the command execution fails while I can do the exact same command a hundred time with no failure. Worse, the issue is not reproducible in mcomix, sometimes some pages will fail to be rendered, sometimes not!

8 - Time to debug some python

I really want to read those PDF so I take my favorite editor and start debugging some python, adding more debug output (mcomix has a -W parameter to enable debug output, which is very nice), to try to understand why it fails at getting output of a working command.

Sadly, my python foo is too low and I wasn’t able to pinpoint the issue. I just found it fail, sometimes, but I wasn’t able to understand why.

9 - mcomix on PowerPC

While mcomix is clunky with PDF, I wanted to check if it was working on PowerPC, it took some times to get all the dependencies installed on my old computer but finally I got mcomix displayed on the screen… and dying on PDF loading! Crash seems related to GTK and I don’t want to touch that, nobody will want to patch GTK for that anyway so I’ve lost hope there.

10 - Looking for alternative

Once I knew about mcomix, I was able to search the Internet for alternatives of it and also CBR readers. A program named zathura seems well known here and we have it in the OpenBSD ports tree.

Weird thing is that it comes with two different PDF plugins, one named mupdf and the other one poppler. I did try quickly on my amd64 machine and zathura was working.

11 - Zathura on PowerPC

As Zathura was working nice on my main computer, I installed it on the PowerPC, first with the poppler plugin, I was able to view PDF, but installing this plugin did pull so many packages dependencies it was a bit sad. I deinstalled the poppler PDF plugin and installed mupdf plugin.

I opened a PDF and… error. I tried again but starting zathura from the terminal, and I got the message that PDF is not a supported format, with a lot of lines related to mupdf.so file not being usable. The mupdf plugin work on amd64 but is not usable on powerpc, this is a bug I need to report, I don’t understand why this issue happens but it’s here.

12 - Back to square one

It seems that reading PDF is a mess, so why couldn’t I convert the PDF to CBT files and then use any CBT reader out there and not having to deal with that PDF madness!!

13 - Use big calibre for the job

I have found on the Internet that Calibre is the most used tool to convert a PDF into CBT files (or into something else but I don’t really care here). I installed calibre, which is not lightweight, started it and wanted to change the default library path, the software did hang when it displayed the file dialog. This won’t stop me, I restart calibre and keep the default path, I click on « Add a book » and then it hang again on file dialog. I did report this issue on ports@ mailing list, but it didn’t solve the issue and this mean calibre is not usable.

14 - Using the command line

After all, CBT files are images in a tar file, it should be easy to reproduce the mcomix process involving mutool to render pictures and make a tar of that.

IT WORKED.

I found two ways to proceed, one is extremely fast but may not make pages in the correct order, the second requires CPU time.

Making CBT files - easiest process

The first way is super easy, it requires mutool (from mupdf package) and it will extract the pictures from the PDF, given it’s not a vector PDF, not sure what would happen on those. The issue is that in the PDF, the embedded pictures have a name (which is a number from the few examples I found), and it’s not necessarily in the correct order. I guess this depend how the PDF is made.

$ mutool extract The_PDF_file.pdf
$ tar cvf The_PDF_file.tar *jpg

That’s all you need to have your CBT file. In my PDF there was jpg files in it, but it may be png in others, I’m not sure.

Making CBT files - safest process (slow)

The other way of making pictures out of the PDF is the one used in mcomix, call mutool for rendering each page as a PNG file using width/height/DPI you want. That’s the tricky part, you may not want to produce pictures with larger resolution than the original pictures (and mutool won’t automatically help you for this) because you won’t get any benefit. This is the same for the DPI. I think this could be done automatically using a correct script checking each PDF page resolution and using mutool to render the page with the exact same resolution.

As a rule of thumb, it seems that rendering using the same width as your screen is enough to produce picture of the correct size. If you use large values, it’s not really an issue, but it will create bigger files and take more time for rendering.

$ mutool draw -w 1920 -o page%d.png The_PDF_file.pdf
$ tar cvf The_PDF_file.tar page*.png

You will get PNG files for each page, correctly numbered, with a width of 1920 pixels. Note that instead of tar, you can use zip to create a zip file.

15 - Finally reading books again

After all this LONG process, I was finally able to read my PDF with any CBR reader out there (even on phone), and once the process is done, it uses no cpu for viewing files at the opposite of mcomix rendering all the pages when you open a file.

I have to use zathura on PowerPC, even if I like it less due to the continuous pages display (can’t be turned off), but mcomix definitely work great when not dealing with PDF. I’m still unsure it’s worth committing mcomix to the ports tree if it fails randomly on random pages with PDF.

16 - Being an open source activist is exhausting

All I wanted was to read a PDF book with a warm cup of tea at hand. It ended into learning new things, debugging code, making ports, submitting bugs and writing a story about all of this.

Daily life with the offline laptop

Written by Solène, on 18 February 2020.
Tags: #life #disconnected

Comments on Fediverse/Mastodon

Last year I wrote a huge blog post about an offline laptop attempt. It kinda worked but I wasn’t really happy with the setups, need and goals.

So, it is back and I use it know, and I am very happy with it. This article explains my experience at solving my needs, I would appreciate not receiving advice or judgments here.

State of the need

Internet is infinite, my time is not

Having access to the Internet is a gift, I can access anything or anyone. But this comes with a few drawbacks. I can waste my time on anything, which is not particularly helpful. There are so many content that I only scratch things, knowing it will still be there when I need it, and jump to something else. The amount of data is impressive, one human can’t absorb that much, we have to deal with it.

I used to spend time of what I had, and now I just spend time on what exist. An example of this statement is that instead of reading books I own, I’m looking for which book I may want to read once, meanwhile no book are read.

Network socialization requires time

When I say “network socialization” this is so to avoid the easy “social network” saying. I do speak with people on IRC (in real time most of the time), I am helping people on reddit, I am reading and writing mail most of the time for OpenBSD development.

Don’t get me wrong, I am happy doing this, but I always keep an eye on each, trying to help people as soon as they ask a question, but this is really time consuming for me. I spend a lot of time jumping from one thing to another to keep myself updated on everything, and so I am too distracted to do anything.

In my first attempt of the offline laptop, I wanted to get my mails on it, but it was too painful to download everything and keep mails in sync. Sending emails would have required network too, it wouldn’t be an offline laptop anymore.

IT as a living and as a hobby

On top of this, I am working in IT so I spend my day doing things over the Internet and after work I spend my time on open source projects. I can not really disconnect from the Internet for both.

How I solved this

First step was to define « What do I like to do? », and I came with this short list:

  • reading
  • listening to music
  • playing video games
  • writing things
  • learning things

One could say I don’t need a computer to read books, but I have lots of ebooks and PDF about lots of subjects. The key is to load everything you need on the computer, because it can be tempting to connect the device to the Internet because you need a bit of this or that.

I use a very old computer with a PowerPC CPU (1.3 GHz single core) with 512MB of ram. I like that old computer, and slower computer forbid doing multiple things at the same time and help me staying on focus.

Reading files

For reading, I found zathura or comix (and its fork mcomix) very useful for reading huge PDF, the scrolling customization make those tools useful.

Listening to music

I buy my music as FLAC files and download it, this doesn’t require any internet access except at purchase time, so nothing special there. I use moc player which is easy to use, have a lot of feature and supports FLAC (on powerpc).

Video games

Emulation is a nice way to play lot of games on OpenBSD, on my old computer it’s up to game boy advance / super nes / megadrive which should allow me to do again lots of games I own.

We also have a lot of nice games in ports, but my computer is too slow to run them or they won’t work on powerpc.

Encyclopedia - Wikipedia

I’ve set up a local wikipedia replica like I explained in a previous article, so anytime I need to find about something, I can ask my local wikipedia. It’s always available. This is the best I found for a local encyclopedia, works well.

Writing things

Since I started the offline computer experience, I started a diary. I never felt the need to do so but I wanted to give it a try. I have to admit summing up what I achieved in the day before going to bed is a satisfying experience and now I continue to update it.

You can use any text editor you want, there are special software with specific features, like rednotebook or lifeograph which supports embedded pictures or on the fly markdown rendering. But a text file and your favorite editor also do the job.

I also write some articles of this blog. It’s easy to do so as articles are text files in a git repository. When I finish and I need to publish, I get network and push changes to the connected computer which will do the publishing job.

Technical details

I will go fast on this. My set up is an old Apple IBook G4 with a 1024x768 screen (I love this 4:3 ratio) running OpenBSD.

The system firewall pf is configured to prevent any incoming connections, and only allow TCP on the network to port 22, because when I need to copy files, I use ssh / sftp. The /home partition is encrypted using the softraid crypto device, full disk encryption is not supported on powerpc.

The experience is even more enjoyable with a warm cup of tea on hand.

Cycling / bike trips and opensource

Written by Solène, on 06 February 2020.
Tags: #biking

Comments on Fediverse/Mastodon

Introduction

I started doing biking seriously a few months ago, as I love having statistics I needed to gather some. I found a lot of devices on the market but I prefered using opensource tool and not relying on any vendor.

The best option to do so for me was reusing a 6 years old smartphone on which the SIM card bus is broken, that phone lose the sim card when it is shaked a little and requires a reboot to find it again, I am happy I found a way to reuse it.

Tip: turn ON airplane mode on the smartphone while riding, even without a SIM card it will try to get network and it will draw battery + emitting useless radio waves. In case of emergency, just disable the airplane mode to get access to your local emergency call number. GPS is a passive module and doesn’t require any network.

This smartphone has a GPS receiver, it’s enough for recording my position as often I want. Using the correct GPS software from F-droid store and a program for sftp transfer, I can record data and transfer it easily to my computer.

The most common file format for recording GPS position is the GPX format, it’s a simple XML file containing all positions with their timestamp, sometimes with a few more information like speed at that time, but given you have all positions, software can calculate the speed between each position.

Android GPS Software

It seems GPS software for recording GPX tracks are becoming popular, and in the last months, lot of new software appeared, which is a good thing, I didn’t tested all of them though but they tend to be more easy to use and minimalistic.

OpenStreetMap app - OSMand~

You can install it from F-droid an alternate store for Android only with opensource software, it’s a full free version (and opensource) compared to the one you can find on Android store.

This is OpenStreetMap official software, it’s full of features and quite heavy, you can download maps for navigation, record tracks, view tracks statistics, contribute to OSM, get Wikipedia information for an area and everything of this while being OFFLINE. Not only on my bike, I use it all the time while walking or in my car.

Recorded GPX can be found in the default path Android/data/net.osmand.plus/files/tracks/rec/

Trekarta

I found another software named Trekarta which is a lot more lighter than OSM, but only focuses on recording your tracks. I would recommend it if you don’t want any other feature or have a really old android compatible phone or low disk space.

Analyzing GPX files / keep track of everything

I found Turtlesport, an opensource software in Java for which last release was years ago but still work out of the box, given you have a java implementation installed. You can find it at the following link.

/usr/local/bin/jdk-1.8.0/bin/java -jar turtlesport.jar

Turtlesport is a nice tool for viewing tracks, it’s not for only for cycling and can be used for various sports, the process is the following:

  • define sports you do (bike, skateboard, hiking etc..)
  • define equipments you use (bike, sport shoes, skis etc..)
  • import GPX files and tell Turtlesport which sport and equipment it’s related to

Then, for each GPX file, you will be able to see it on a map, see elevation and speed of that track, but you can also make statistics per sport or equipment, like “How many km I ride with that bike over last year, per week”.

If you don’t have a GPX file, you can still add a new trip into the database by drawing the path on a map.

In the equipments, you will see how many kilometers you used each, with an alert feature if the equipment goes beyond a defined wearing limit. I’m not sure about the use of this, maybe you want to know your shoes shouldn’t be used for more than 2000 km?? Maybe it’s possible to use it for maintenance purpose, says your bike has a wearing limit of 1000 km, when you reach it you get an alert, do your maintenance and set the new limit to 2000km.

Viewing GPX files

From OpenBSD 6.7 you can install the package gpxsee to open multiple GPX files, they will be shown on a map, each track with a different colour, and nice charts displaying the elevation or speed over the travel for every tracks.

Before gpxsee I was using the GIS (Geographical Information System) tool qgis but it is really heavy and complicated. But if you want to work on your recorded data like doing complex statistics, it’s a powerful tool if you know how to use it.

I like to use it in a gamification purpose: I’m trying to ride over every road around my home, viewing all GPX files at the same time allow me to plan the next trip where I never went.

Miscellaneous

Create an unique GPX file from all records

It is possible to merge GPX file into one giant one using gpsbabel .I was using this before having *gpxsee but I have no idea about what you can do with that, this create one big spaggheti track. I choose to keep the command here, in case it’s useful for someone one day:

gpsbabel -s -r -t -i GPX $(ls /path/to/files/*gpx | awk '{ printf "-f %s ", $1 }') -o GPX -F - > sum.gpx

Cycling using electronic devices

Of course, if you are a true cyclist racer and GPX files will not be enough for you, you will certainly want devices such as a power meter or a cadence meter and an on-board device to use them. I can’t help much about hardware.

However, you may want to give a try to Golden Cheetah to import all your data from various devices and make complex statistics from it. I tried it and I had no idea about the purpose of 90% of the features.

Have fun

Don’t forget to have fun and do not get obscessed by numbers!

Common LISP awk macro for easy text file operations

Written by Solène, on 04 February 2020.
Tags: #awk #lisp

Comments on Fediverse/Mastodon

I like Common LISP and I also like awk. Dealing with text files in Common LISP is often painful. So I wrote a small awk like common lisp macro, which helps a lot dealing with text files.

Here is the implementation, I used the uiop package for split-string function, it comes with sbcl. But it's possible to write your own split-string or reused the infamous split-str function shared on the Internet.

(defmacro awk(file separator &body code)
  "allow running code for each line of a text file,
   giving access to NF and NR variables, and also to
   fields list containing fields, and line containing $0"
    `(progn
       (let ((stream (open ,file :if-does-not-exist nil)))
         (when stream
           (loop for line = (read-line stream nil)
              counting t into NR
              while line do
                (let* ((fields (uiop:split-string line :separator ,separator))
                       (NF (length fields)))
                  ,@code))))))

It's interesting that the "do" in the loop could be replaced with a "collect", allowing to reuse awk output as a list into another function, a quick example I have in mind is this:

;; equivalent of awk '{ print NF }' file | sort | uniq
;; for counting how many differents fields long line we have
(uniq (sort (awk "file" " " NF)))

Now, here are a few examples of usage of this macro, I've written the original awk command in the comments in comparison:

;; numbering lines of a text file with NR
;; awk '{ print NR": "$0 }' file.txt
;;
(awk "file.txt" " "
     (format t "~a: ~a~%" NR line))

;; display NF-1 field (yes it's -2 in the example because -1 is last field in the list)
;; awk -F ';' '{ print NF-1 }' file.csv
;;
(awk "file.csv" ";"
     (print (nth (- NF 2) fields)))

;; filtering lines (like grep)
;; awk '/unbound/ { print }' /var/log/messages
;;
(awk "/var/log/messages" " "
     (when (search "unbound" line)
       (print line)))

;; printing 4nth field
;; awk -F ';' '{ print $4 }' data.csv
;;
(awk "data.csv" ";"
     (print (nth 4 fields)))

Using the OpenBSD ports tree with dedicated users

Written by Solène, on 11 January 2020.
Tags: #openbsd

Comments on Fediverse/Mastodon

If you want to contribute to OpenBSD ports collection you will want to enable thePORTS_PRIVSEP feature. When this variable is set, ports system will use dedicated users for tasks.

Source tarballs will be downloaded by the user _pfetch and all compilation and packaging will be done by the user _pbuild.

Those users are created at system install and pf have a default rule to prevent _pbuild user doing network access. This will prevent ports from doing network stuff, and this is what you want.

This adds a big security to the porting process and any malicious code run by ports being compiled will be harmless.

In order to enable this feature, a few changes must be made.

The file /etc/mk.conf must contains

PORTS_PRIVSEP=yes
SUDO=doas

Then, /etc/doas.conf must allows your user to become _pfetch and _pbuild

permit keepenv nopass solene as _pbuild
permit keepenv nopass solene as _pfetch
permit keepenv solene as root

If you don’t want to use the last line, there is an explanation in the bsd.port.mk(5) man page.

Finally, within the ports tree, some permissions must be changed.

# chown -R _pfetch:_pfetch /usr/ports/distfiles
# chown -R _pbuild:_pbuild /usr/ports/{packages,plist,pobj,bulk}

If directories doesn’t exist yet on your system (this is the case on a fresh ports checkout / untar), you can create them with the commands:

# install -d -o _pfetch -g _pfetch /usr/ports/distfiles
# install -d -o _pbuild -g _pbuild /usr/ports/{packages,plist,pobj,bulk}

Now, when you run a command in the ports tree, privileges should be dropped to according users.

Using rsnapshot for easy backups

Written by Solène, on 10 January 2020.
Tags: #openbsd

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Introduction

rsnapshot is a handy tool to manage backups using rsync and hard links on the filesystem. rsnapshot will copy folders and files but it will skip duplication over backups using hard links for files which has not changed.

This kinda create snapshots of your folders you want to backup, only using rsync, it’s very efficient and easy to use, and getting files from backups is really easy as they are stored as files under the rsnapshot backup.

Installation

Installing rsnapshot is very easy, on most systems it will be in your official repository packages.

To install it on OpenBSD: pkg_add rsnapshot (as root)

Configuration

Now you may want to configure it, in OpenBSD you will find a template in /etc/rsnapshot.conf that you can edit for your needs (you can make a backup of it first if you want to start over). As it’s stated in big (as big as it can be displayed in a terminal) letters at the top of the configuration sample file, you will see that things must be separated by TABS and not spaces. I’ve made the mistakes more than once, don’t forget using tabs.

I won’t explain all options, but only the most importants.

The variable snapshot_root is where you want to store the backups. Don’t put that directory in a directory you will backup (that will end into an infinite loop)

The variable backup is for telling rsnapshot what you want to backup from your system to which directory inside snapshot_root

Here are a few examples:

backup	/home/solene/	myfiles/
backup	/home/shera/Documents	shera_files/
backup	/home/shera/Music	shera_files/
backup	/etc/	etc/
backup	/var/	var/	exclude=logs/*

Be careful when using ending slashes to paths, it works the same as with rsync. /home/solene/ means that into target directory, it will contains the content of /home/solene/ while /home/solene will copy the folder solene within the target directory, so you end up with target_directory/solene/the_files_here.

The variables retain are very important, this will define how rsnapshot keep your data. In the example you will see alpha, beta, gamma but it could be hour, day, week or foo and bar. It’s only a name that will be used by rsnapshot to name your backups and also that you will use to tell rsnapshot which kind of backup to do. Now, I must explain how rsnapshot actually work.

How it work

Let’s go for a straighforward configuration. We want a backup every hour on the last 24h, a backup every day for the past 7 days and 3 manuals backup that we start manually.

We will have this in our rsnapshot configuration

retain	hourly	24
retain	daily	7
retain	manual	3

but how does rsnapshot know how to do what? The answer is that it doesn’t.

In root user crontab, you will have to add something like this:

# run rsnapshot every hour at 0 minutes
0 * * * * rsnapshot hourly

# run rsnapshot every day at 4 hours 0 minutes
0 4 * * * rsnapshot daily

and then, when you want to do a manual backup, just start rsnapshot manual

Every time you run rsnapshot for a “kind” of backup, the last version will be named in the rsnapshoot root directory like hourly.0 and every backups will be shifted by one. The directory getting a number higher than the number in the retain line will be deleted.

New to crontab?

If you never used crontab, I will share two important things to know about it.

Use MAILTO=“” if you don’t want to receive every output generated from scripts started by cron.

Use a PATH containing /usr/local/bin/ in it because in the default cron PATH it is not present. Instead of setting PATH you can also using full binary paths into the crontab, like /usr/local/bin/rsnapshot daily

You can edit the current user crontab with the command crontab -e.

Your crontab may then look like:

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/X11R6/bin:/usr/local/bin:/usr/local/sbin
MAILTO=""
# comments are allowed in crontab
# run rsnapshot every hour at 0 minutes
0 * * * * rsnapshot hourly
# run rsnapshot every day at 4 hours 0 minutes
0 4 * * * rsnapshot daily

Crop a video using ffmpeg

Written by Solène, on 20 December 2019.
Tags: #ffmpeg

Comments on Fediverse/Mastodon

If you ever need to crop a video, which mean that you want to reduce the area of the video to a square of it to trim areas you don’t want.

This is possible with ffmpeg using the video filter crop. To make the example more readable, I replaced values with variables names:

  • WIDTH = width of output video
  • HEIGHT = height of output video
  • START_LEFT = relative position of the area compared to the left, left being 0
  • START_TOP = relative position of the area compared to the top, top being 0

So the actual commands look like

ffmpeg -i input_video.mp4 -filter:v "crop=$WIDTH:$HEIGHT:$START_LEFT:$START_TOP" output_video.mp4

If you want to crop the video to get a 320x240 video from the top-left position 500,100 the command would be

ffmpeg -i input_video.mp4 -filter:v "crop=320:240:500:100" output_video.mp4

Separate or merge audio and video using ffmpeg

Written by Solène, on 20 December 2019.
Tags: #ffmpeg

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Extract audio and video (separation)

If for some reasons you want to separate the audio and the video from a file you can use those commands:

ffmpeg -i input_file.flv -vn -acodec copy audio.aac

ffmpeg -i input_file.flv -an -vcodec copy video.mp4

Short explanation:

  • -vn means -video null and so you discard video
  • -an means -audio null and so you discard audio
  • codec copy means the output is using original format from the file. If the audio is mp3 then the output file will be a mp3 whatever the extension you choose.

Instead of using codec copy you can choose a different codec for the extracted file, but copy is a good choice, it performs really fast because you don’t need to re-encode it and is loss-less.

I use this to rework the audio with audacity.

Merge audio and video into a single file (merge)

After you reworked tracks (audio and/or video) of your file, you can combine them into a single file.

ffmpeg -i input_audio.aac -i input_video.mp4 -acodec copy -vcodec copy -f flv merged_video.flv

Playing CrossCode within a web browser

Written by Solène, on 09 December 2019.
Tags: #gaming #openbsd #openindiana

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Good news for my gamers readers. It’s not really fresh news but it has never been written anywhere.

The commercial video game Crosscode is written in HTML5, making it available on every system having chromium or firefox. The limitation is that it may not support gamepad (except if you find a way to make it work).

A demo is downloadable at this address https://radicalfishgames.itch.io/crosscode and should work using the following instructions.

You need to buy the game to be able to play it, it’s not free and not opensource. Once you bought it, the process is easy:

  1. Download the linux installer from GOG (from steam it may be too)
  2. Extract the data
  3. Patch a file if you want to use firefox
  4. Serve the files through a http server

The first step is to buy the game and get the installer.

Once you get a file named like “crosscode_1_2_0_4_32613.sh”, run unzip on it, it’s a shell script but only a self contained archive that can extract itself using the small shell script at the top.

Change directory into data/noarch/game/assets and apply this patch, if you don’t know how to apply a patch or don’t want to, you only need to remove/comment the part you can see in the following patch:

--- node-webkit.html.orig	Mon Dec  9 17:27:17 2019
+++ node-webkit.html	Mon Dec  9 17:27:39 2019
@@ -51,12 +51,12 @@
 <script type="text/javascript">
     // make sure we don't let node-webkit show it's error page
     // TODO for release mode, there should be an option to write to a file or something.
-    window['process'].once('uncaughtException', function() {
+/*    window['process'].once('uncaughtException', function() {
         var win = require('nw.gui').Window.get();
         if(!(win.isDevToolsOpen && win.isDevToolsOpen())) {
             win.showDevTools && win.showDevTools();
         }
-    });
+    });*/
     
     function doStartCrossCodePlz(){
       if(window.startCrossCode){

Then you need to start a http server in the current path, an easy way to do it is using… php! Because php contains a http server, you can start the server with the following command:

$ php -S 127.0.0.1:8080

Now, you can play the game by opening http://localhost:8080/node-webkit.html

I really thank Thomas Frohwein aka thfr@ for finding this out!

Tested on OpenBSD and OpenIndiana, it works fine on an Intel Core 2 Duo T9400 (CPU from 2008).

Host your own wikipedia backup

Written by Solène, on 13 November 2019.
Tags: #openbsd #wikipedia #life

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Wikipedia and openzim

If you ever wanted to host your own wikipedia replica, here is the simplest way.

As wikipedia is REALLY huge, you don’t really want to host a php wikimedia software and load the huge database, instead, the project made the openzim format to compress the huge database that wikipedia became while allowing using it for fast searches.

Sadly, on OpenBSD, we have no software reading zim files and most software requires the library openzim to work which requires extra work to get it as a package on OpenBSD.

Hopefully, there is a python package implementing all you need as pure python to serve zim files over http and it’s easy to install.

This tutorial should work on all others unix like systems but packages or binary names may change.

Downloading wikipedia

The project Kiwix is responsible for wikipedia files, they create regularly files from various projects (including stackexchange, gutenberg, wikibooks etc…) but for this tutorial we want wikipedia: https://wiki.kiwix.org/wiki/Content_in_all_languages

You will find a lot of files, the language is contained into the filename. Some filenames will also self explain if they contain everything or categories, and if they have pictures or not.

The full French file is 31.4 GB worth.

Running the server

For the next steps, I recommend setting up a new user dedicated to this.

On OpenBSD, we will require python3 and pip:

$ doas pkg_add py3-pip--

Then we can use pip to fetch and install dependencies for the zimply software, the flag --user is rather important as it allows any user to download and install python libraries in its home folder instead of polluting the whole system as root.

$ pip3.7 install --user --upgrade zimply 

I wrote a small script to start the server using the zim file as a parameter, I rarely write python so the script may not be high standard.

File server.py:

from zimply import ZIMServer
import sys
import os.path
    
if len(sys.argv) == 1:
    print("usage: " + sys.argv[0] + " file")
    exit(1)
    
if os.path.exists(sys.argv[1]):
    ZIMServer(sys.argv[1])
else:
    print("Can't find file " + sys.argv[1])

And then you can start the server using the command:

$ python3.7 server.py /path/to/wikipedia_fr_all_maxi_2019-08.zim

You will be able to access wikipedia on the url http://localhost:9454/

Note that this is not a “wiki” as you can’t see history and edit/create pages.

This kind of backup is used in place like Cuba or Africa areas where people don’t have unlimited internet access, the project lead by Kiwix allow more people to access knowledge.

Creating new users dedicated to processes

Written by Solène, on 12 November 2019.
Tags: #openbsd

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What this article is about ?

For some times I wanted to share how I manage my personal laptop and systems. I got the habit to create a lot of users for just everything for security reasons.

Creating a new users is fast, I can connect as this user using doas or ssh -X if I need a X app and this allows preventing some code to steal data from my main account.

Maybe I went this way too much, I have a dedicated irssi users which is only for running irssi, same with mutt. I also have a user with a stupid name and I can use it for testing X apps and I can wipe the data in its home directory (to try fresh firefox profiles in case of ports update for example).

How to proceed?

Creating a new user is as easy as this command (as root):

# useradd -m newuser
# echo "permit keepenv solene as newuser" >> /etc/doas.conf

Then, from my main user, I can do:

$ doas -u newuser 'mutt'

and it will run mutt as this user.

This way, I can easily manage lots of services from packages which don’t come with dedicated daemons users.

For this to be effective, it’s important to have a chmod 700 on your main user account, so others users can’t browse your files.

Graphicals software with dedicated users

It becomes more tricky for graphical users. There are two options there:

  • allow another user to use your X session, it will have native performance but in case of security issue in the software your whole X session is accessible (recording keys, screnshots etc…)
  • running the software through ssh -X will restricts X access to the software but the rendering will be a bit sluggish and not suitable for some uses.

Example of using ssh -X compared to ssh -Y:

$ ssh -X foobar@localhost scrot
X Error of failed request:  BadAccess (attempt to access private resource denied)
  Major opcode of failed request:  104 (X_Bell)
  Serial number of failed request:  6
  Current serial number in output stream:  8

$ ssh -Y foobar@localhost scrot
(nothing output but it made a screenshot of the whole X area)

Real world example

On a server I have the following new users running:

  • torrents
  • idlerpg
  • searx
  • znc
  • minetest
  • quake server
  • awk cron parsing http

they can have crontabs.

Maybe I use it too much, but it’s fine to me.

How to remove a part of a video using ffmpeg

Written by Solène, on 02 October 2019.
Tags: #ffmpeg

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If you want to remove parts of a video, you have to cut it into pieces and then merge the pieces, so you can avoid parts you don’t want.

The command is not obvious at all (like in all ffmpeg uses), I found some parts on differents areas of the Internet.

Split in parts, we want to keep from 00:00:00 to 00:30:00 and 00:35:00 to 00:45:00

ffmpeg -i source_file.mp4 -ss 00:00:00 -t 00:30:00 -acodec copy -vcodec copy part1.mp4
ffmpeg -i source_file.mp4 -ss 00:35:00 -t 00:10:00 -acodec copy -vcodec copy part2.mp4

The -ss parameter tells ffmpeg where to start the video and -t parameter tells it about the duration.

Then, merge the files into one file:

printf "file %s\n" part1.mp4 part2.mp4 > file_list.txt
ffmpeg -f concat -i file_list.txt -c copy result.mp4

instead of printf you can write into file_list.txt the list of files like this:

file /path/to/test1.mp4
file /path/to/test2.mp4

GPG2 cheatsheet

Written by Solène, on 06 September 2019.
Tags: #security

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Introduction

I don’t use gpg a lot but it seems the only tool out there for encrypting data which “works” and widely used.

So this is my personal cheatsheet for everyday use of gpg.

In this post, I use the command gpg2 which is the binary to GPG version 2. On your system, “gpg” command could be gpg2 or gpg1. You can use gpg --versionif you want to check the real version behind gpg binary.

In your ~/.profile file you may need the following line:

export GPG_TTY=$(tty)

Install GPG

The real name of GPG is GnuPG, so depending on your system the package can be either gpg2, gpg, gnupg, gnugp2 etc…

On OpenBSD, you can install it with: pkg_add gnupg--%gnupg2

GPG Principle using private/public keys

  • YOU make a private and a public key (associated with a mail)
  • YOU give the public key to people
  • PEOPLE import your public key into they keyring
  • PEOPLE use your public key from the keyring
  • YOU will need your password everytime

I think gpg can do much more, but read the manual for that :)

Initialization

We need to create a public and a private key.

solene$ gpg2 --gen-key
gpg (GnuPG) 2.2.12; Copyright (C) 2018 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
    
Note: Use "gpg2 --full-generate-key" for a full featured key generation dialog.
    
GnuPG needs to construct a user ID to identify your key.

In this part, you should put your real name and your email address and validate with “O” if you are okay with the input. You will get ask for a passphrase after.

Real name: Solene
Email address: solene@domain.example
You selected this USER-ID:
    "Solene <solene@domain.example>"
    
Change (N)ame, (E)mail, or (O)kay/(Q)uit? o
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
gpg: key 368E580748D5CA75 marked as ultimately trusted
gpg: revocation certificate stored as '/home/solene/.gnupg/openpgp-revocs.d/7914C6A7439EADA52643933B368E580748D5CA75.rev'
public and secret key created and signed.
    
pub   rsa2048 2019-09-06 [SC] [expires: 2021-09-05]
      7914C6A7439EADA52643933B368E580748D5CA75
uid                    Solene <solene@domain.example>
sub   rsa2048 2019-09-06 [E] [expires: 2021-09-05]

The key will expire in 2 years, but this is okay. This is a good thing, if you stop using the key, it will die silently at it expiration time. If you still use it, you will be able to extend the expiracy time and people will be able to notice you still use that key.

Export the public key

If someone asks your GPG key, this is what they want:

gpg2 --armor --export solene@domain.example > solene.asc

Import a public key

Import the public key:

gpg2 --import solene.asc

If you want to mark this signature as trusted:

gpg --edit-key FINGERPRINT_HERE
> sign
# do you want to sign? (y/n): y
> save

Delete a public key

In case someone change their public key, you will want to delete it to import a new one, replace $FINGERPRINT by the actual fingerprint of the public key.

gpg2 --delete-keys $FINGERPRINT

Encrypt a file for someone

If you want to send file picture.jpg to remote@mail then use the command:

gpg2 --encrypt --recipient remote@domain.example picture.jpg > picture.jpg.gpg

You can now send picture.jpg.gpg to remote@mail who will be able to read the file with his/her private key.

You can use `–armor`` parameter to make the output plaintext, so you can put it into a mail or a text file.

Decrypt a file

Easy!

gpg2 --decrypt image.jpg.gpg > image.jpg

Get public key fingerprint

The fingerprint is a short string made out of your public key and can be embedded in a mail (often as a signature) or anywhere.

It allows comparing a public key you received from someone with the fingerprint that you may find in mailing list archives, twitter, a html page etc.. if the person spreaded it somewhere. This allow to multiple check the authenticity of the public key you received.

it looks like:

4398 3BAD 3EDC B35C 9B8F  2442 8CD4 2DFD 57F0 A909

This is my real key fingerprint, so if I send you my public key, you can use the fingerprint from this page to check it matches the key you received!

You can obtain your fingerprint using the following command:

solene@t480 ~ $ gpg2 --fingerprint
pub   rsa4096 2018-06-08 [SC]
      4398 3BAD 3EDC B35C 9B8F  2442 8CD4 2DFD 57F0 A909
uid          [  ultime ] XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
sub   rsa4096 2018-06-08 [E]

Add a new mail / identity

If for some reason, you need to add another mail to your GPG key (like personal/work keys) you can create a new identity with the new mail.

Type gpg2 --edit-key solene@domain.example and then in the prompt, type adduid and answer questions.

You can now export the public key with a different identity.

List known keys

If you want to get the list of keys you imported, you can use

gpg2 -k

Testing

If you want to do some tests, I’d recommend making new users on your system, exchanges their keys and try to encrypt a message from one user to another.

I have a few spare users on my system on which I can ssh locally for various tests, it is always useful.

Stream live video using nginx

Written by Solène, on 26 August 2019.
Tags: #openbsd #gaming #nginx

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This blog post is about a nginx rtmp module for turning your nginx server into a video streaming server.

The official website of the project is located on github at: https://github.com/arut/nginx-rtmp-module/

I use it to stream video from my computer to my nginx server, then viewers can use mpv rtmp://perso.pw/gaming in order to view the video stream. But the nginx server will also relay to twitch for more scalability (and some people prefer viewing there for some reasons).

The module will already be installed with nginx package since OpenBSD 6.6 (not already out at this time).

There is no package for install the rtmp module before 6.6. On others operating systems, check for something like “nginx-rtmp” or “rtmp” in an nginx context.

Install nginx on OpenBSD:

pkg_add nginx

Then, add the following to the file /etc/nginx/nginx.conf

load_module modules/ngx_rtmp_module.so;
rtmp {
    server {
        listen 1935;
        buflen 10s;
    
        application gaming {
            live on;
            allow publish 176.32.212.34;
            allow publish 175.3.194.6;
            deny publish all;
            allow play all;
    
            record all;
            record_path /htdocs/videos/;
            record_suffix %d-%b-%y_%Hh%M.flv;
    
        }
    }
}

The previous configuration sample is a simple example allowing 172.32.212.34 and 175.3.194.6 to stream through nginx, and that will record the videos under /htdocs/videos/ (nginx is chrooted in /var/www).

You can add the following line in the “application” block to relay the stream to your Twitch broadcasting server, using your API key.

push rtmp://live-ams.twitch.tv/app/YOUR_API_KEY;

I made a simple scripts generating thumbnails of the videos and generating a html index file.

Every 10 minutes, a cron check if files have to be generated, make thumbnails for videos (tries at 05:30 of the video and then 00:03 if it doesn’t work, to handle very small videos) and then create the html.

The script checking for new stuff and starting html generation:

#!/bin/sh
    
cd /var/www/htdocs/videos
    
for file in $(find . -mmin +1 -name '*.flv')
do
        echo $file
        PIC=$(echo $file | sed 's/flv$/jpg/')
        if [ ! -f "$PIC" ]
        then
                ffmpeg -ss 00:05:30 -i "$file" -vframes 1 -q:v 2 "$PIC"
                if [ ! -f "$PIC" ]
                then
                        ffmpeg -ss 00:00:03 -i "$file" -vframes 1 -q:v 2 "$PIC"
                        if [ ! -f "$PIC" ]
                        then
                                echo "problem with $file" | mail user@my-tld.com
                        fi
                fi
        fi
done
cd ~/dev/videos/ && sh html.sh

This one makes the html:

#!/bin/sh
    
cd /var/www/htdocs/videos
    
PER_ROW=3
COUNT=0
    
cat << EOF > index.html
<html>
  <body>
<h1>Replays</h1>
<table>
EOF
    
for file in $(find . -mmin +3 -name '*.flv')
do
        if [ $COUNT -eq 0 ]
        then
                echo "<tr>" >> index.html
                INROW=1
        fi
        COUNT=$(( COUNT + 1 ))
        SIZE=$(ls -lh $file  | awk '{ print $5 }')
        PIC=$(echo $file | sed 's/flv$/jpg/')
    
        echo $file
        echo "<td><a href=\"$file\"><img src=\"$PIC\" width=320 height=240 /><br />$file ($SIZE)</a></td>" >> index.html
        if [ $COUNT -eq $PER_ROW ]
        then
                echo "</tr>" >> index.html
                COUNT=0
                INROW=0
        fi
done
    
if [ $INROW -eq 1 ]
then
        echo "</tr>" >> index.html
fi
    
cat << EOF >> index.html
    </table>
  </body>
</html>
EOF

Minimalistic markdown subset to html converter using awk

Written by Solène, on 26 August 2019.
Tags: #unix #awk

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Hello

As on my blog I use different markup languages I would like to use a simpler markup language not requiring an extra package. To do so, I wrote an awk script handling titles, paragraphs and code blocks the same way markdown does.

16 December 2019 UPDATE: adc sent me a patch to add ordered and unordered list. Code below contain the addition.

It is very easy to use, like: awk -f mmd file.mmd > output.html

The script is the following:

BEGIN {
	in_code=0
	in_list_unordered=0
	in_list_ordered=0
	in_paragraph=0
}
    
{
	# escape < > characters
	gsub(/</,"\<",$0);
	gsub(/>/,"\>",$0);
    
	# close code blocks
	if(! match($0,/^    /)) {
		if(in_code) {
			in_code=0
			printf "</code></pre>\n"
		}
	}
    
	# close unordered list
	if(! match($0,/^- /)) {
		if(in_list_unordered) {
			in_list_unordered=0
			printf "</ul>\n"
		}
	}
    
	# close ordered list
	if(! match($0,/^[0-9]+\. /)) {
		if(in_list_ordered) {
			in_list_ordered=0
			printf "</ol>\n"
		}
	}
    
	# display titles
	if(match($0,/^#/)) {
		if(match($0,/^(#+)/)) {
			printf "<h%i>%s</h%i>\n", RLENGTH, substr($0,index($0,$2)), RLENGTH
		}
    
	# display code blocks
	} else if(match($0,/^    /)) {
		if(in_code==0) {
			in_code=1
			printf "<pre><code>"
			print substr($0,5)
		} else {
			print substr($0,5)
		}
    
	# display unordered lists
	} else if(match($0,/^- /)) {
		if(in_list_unordered==0) {
			in_list_unordered=1
			printf "<ul>\n"
			printf "<li>%s</li>\n", substr($0,3)
		} else {
			printf "<li>%s</li>\n", substr($0,3)
		}
    
	# display ordered lists
	} else if(match($0,/^[0-9]+\. /)) {
		n=index($0," ")+1
		if(in_list_ordered==0) {
			in_list_ordered=1
			printf "<ol>\n"
			printf "<li>%s</li>\n", substr($0,n)
		} else {
			printf "<li>%s</li>\n", substr($0,n)
		}
    
	# close p if current line is empty
	} else {
		if(length($0) == 0 && in_paragraph == 1 && in_code == 0) {
			in_paragraph=0
			printf "</p>"
		} # we are still in a paragraph
		if(length($0) != 0 && in_paragraph == 1) {
			print
		} # open a p tag if previous line is empty
		if(length(previous_line)==0 && in_paragraph==0) {
			in_paragraph=1
			printf "<p>%s\n", $0
		}
	}
	previous_line = $0
}
    
END {
	if(in_code==1) {
		printf "</code></pre>\n"
	}
	if(in_list_unordered==1) {
		printf "</ul>\n"
	}
	if(in_list_ordered==1) {
		printf "</ol>\n"
	}
	if(in_paragraph==1) {
		printf "</p>\n"
	}
}

Life with an offline laptop

Written by Solène, on 23 August 2019.
Tags: #openbsd #life #disconnected

Comments on Fediverse/Mastodon

Hello, this is a long time I want to work on a special project using an offline device and work on it.

I started using computers before my parents had an internet access and I was enjoying it. Would it still be the case if I was using a laptop with no internet access?

When I think about an offline laptop, I immediately think I will miss IRC, mails, file synchronization, Mastodon and remote ssh to my servers. But do I really need it _all the time_?

As I started thinking about preparing an old laptop for the experiment, differents ideas with theirs pros and cons came to my mind.

Over the years, I produced digital data and I can not deny this. I don't need all of them but I still want some (some music, my texts, some of my programs). How would I synchronize data from the offline system to my main system (which has replicated backups and such).

At first I was thinking about using a serial line over the two laptops to synchronize files, but both laptop lacks serial ports and buying gears for that would cost too much for its purpose.

I ended thinking that using an IP network _is fine_, if I connect for a specific purpose. This extended a bit further because I also need to install packages, and using an usb memory stick from another computer to get packages and allow the offline system to use it is _tedious_ and ineffective (downloading packages and correct dependencies is a hard task on OpenBSD in the case you only want the files). I also came across a really specific problem, my offline device is an old Apple PowerPC laptop being big-endian and amd64 is little-endian, while this does not seem particularly a problem, OpenBSD filesystem is dependent of endianness, and I could not share an usb memory device using FFS because of this, alternatives are fat, ntfs or ext2 so it is a dead end.

Finally, using the super slow wireless network adapter from that offline laptop allows me to connect only when I need for a few file transfers. I am using the system firewall pf to limit access to outside.

In my pf.conf, I only have rules for DNS, NTP servers, my remote server, OpenBSD mirror for packages and my other laptop on the lan. I only enable wifi if I need to push an article to my blog or if I need to pull a bit more music from my laptop.

This is not entirely _offline_ then, because I can get access to the internet at any time, but it helps me keeping the device offline. There is no modern web browser on powerpc, I restricted packages to the minimum.

So far, when using this laptop, there is no other distraction than the stuff I do myself.

At the time I write this post, I only use xterm and tmux, with moc as a music player (the audio system of the iBook G4 is surprisingly good!), writing this text with ed and a 72 long char prompt in order to wrap words correctly manually (I already talked about that trick!).

As my laptop has a short battery life, roughly two hours, this also helps having "sessions" of a reasonable duration. (Yes, I can still plug the laptop somewhere).

I did not use this laptop a lot so far, I only started the experiment a few days ago, I will write about this sometimes.

I plan to work on my gopher space to add new content only available there :)

OpenBSD ttyplot examples

Written by Solène, on 29 July 2019.
Tags: #openbsd #ttyplot

Comments on Fediverse/Mastodon

I said I will rewrite ttyplot examples to make them work on OpenBSD.

Here they are, but a small notice before:

Examples using systat will only work for 10000 seconds , or increase that -d parameter, or wrap it in an infinite loop so it restart (but don’t loop systat for one run at a time, it needs to start at least once for producing results).

The systat examples won’t work before OpenBSD 6.6, which is not yet released at the time I’m writing this, but it’ll work on a -current after 20 july 2019.

I made a change to systat so it flush output at every cycle, it was not possible to parse its output in realtime before.

Enjoy!

Examples list

ping

Replace test.example by the host you want to ping.

ping test.example | awk '/ms$/ { print substr($7,6) ; fflush }' | ttyplot -t "ping in ms"

cpu usage

vmstat 1 | awk 'NR>2 { print 100-$(NF); fflush(); }' | ttyplot -t "Cpu usage" -s 100

disk io

 systat -d 1000 -b  iostat 1 | awk '/^sd0/ && NR > 20 { print $2/1024 ; print $3/1024 ; fflush }' | ttyplot -2 -t "Disk read/write in kB/s"

load average 1 minute

{ while :; do uptime ; sleep 1 ; done } | awk '{ print substr($8,0,length($8)-1) ; fflush }' | ttyplot -t "load average 1"

load average 5 minutes

{ while :; do uptime ; sleep 1 ; done } | awk '{ print substr($9,0,length($9)-1) ; fflush }' | ttyplot -t "load average 5"

load average 15 minutes

{ while :; do uptime ; sleep 1 ; done } | awk '{ print $10 ; fflush }' | ttyplot -t "load average 15"

wifi signal strengh

Replace iwm0 by your interface name.

{ while :; do ifconfig iwm0 | tr ' ' '\n' ; sleep 1 ; done } | awk '/%$/ { print ; fflush }' | ttyplot -t "Wifi strength in %" -s 100

cpu temperature

{ while :; do sysctl -n hw.sensors.cpu0.temp0 ; sleep 1 ; done } | awk '{ print $1 ; fflush }' | ttyplot -t "CPU temperature in °C"

pf state searches rate

systat -d 10000 -b pf 1 | awk '/state searches/ { print $4 ; fflush }' | ttyplot -t "PF state searches per second"

pf state insertions rate

systat -d 10000 -b pf 1 | awk '/state inserts/ { print $4 ; fflush }' | ttyplot -t "PF state searches per second"

network bandwidth

Replace trunk0 by your interface. This is the same command as in my previous article.

netstat -b -w 1 -I trunk0 | awk 'NR>3 { print $1/1024; print $2/1024; fflush }' | ttyplot -2 -t "IN/OUT Bandwidth in KB/s" -u "KB/s" -c "#"

Tip

You can easily use those examples over ssh for gathering data, and leave the plot locally as in the following example:

ssh remote_server "netstat -b -w 1 -I trunk0" | awk 'NR>3 { print $1/1024; print $2/1024; fflush }' | ttyplot -2 -t "IN/OUT Bandwidth in KB/s" -u "KB/s" -c "#"

or

ssh remote_server "ping test.example" | awk '/ms$/ { print substr($7,6) ; fflush }' | ttyplot -t "ping in ms"

Realtime bandwidth terminal graph visualization

Written by Solène, on 19 July 2019.
Tags: #openbsd #ttyplot

Comments on Fediverse/Mastodon

If for some reasons you want to visualize your bandwidth traffic on an interface (in or out) in a terminal with a nice graph, here is a small script to do so, involving ttyplot, a nice software making graphics in a terminal.

The following will works on OpenBSD. You can install ttyplot by pkg_add ttyplot as root, ttyplot package appeared since OpenBSD 6.5.

For Linux, the ttyplot official website contains tons of examples.

Example

Output example while updating my packages:

                                          IN Bandwidth in KB/s
  ↑ 1499.2 KB/s#
  │            #
  │            #
  │            #
  │            ##
  │            ##
  │ 1124.4 KB/s##
  │            ##
  │            ##
  │            ##
  │            ##
  │            ##
  │ 749.6 KB/s ##
  │            ##
  │            ##
  │            ##                                                    #
  │            ##      # #       #                     #             ##
  │            ##  #   ###    # ##      #  #  #        ##            ##         #         # ##
  │ 374.8 KB/s ## ##  ####  # # ## # # ### ## ##      ###  #      ## ###    #   #     #   # ##   #    ##
  │            ## ### ##### ########## #############  ###  # ##  ### ##### #### ##    ## ###### ##    ##
  │            ## ### ##### ########## #############  ###  ####  ### ##### #### ## ## ## ###### ##   ###
  │            ## ### ##### ########## ############## ###  ####  ### ##### #### ## ## ######### ##  ####
  │            ## ### ##### ############################## ######### ##### #### ## ## ############  ####
  │            ## ### #################################################### #### ## #####################
  │            ## ### #################################################### #############################
  └────────────────────────────────────────────────────────────────────────────────────────────────────→
     # last=422.0 min=1.3 max=1499.2 avg=352.8 KB/s                             Fri Jul 19 08:30:25 2019
                                                                           github.com/tenox7/ttyplot 1.4

In the following command, we will use trunk0 with INBOUND traffic as the interface to monitor.

At the end of the article, there is a command for displaying both in and out at the same time, and also instructions for customizing to your need.

Article update: the following command is extremely long and complicated, at the end of the article you can find a shorter and more efficient version, removing most of the awk code.

You can copy/paste this command in your OpenBSD system shell, this will produce a graph of trunk0 inbound traffic.

{ while :; do netstat -i -b -n ; sleep 1 ; done } | awk 'BEGIN{old=-1} /^trunk0/ { if(!index($4,":") && old>=0)  { print ($5-old)/1024 ; fflush  ; old = $5 } if(old==-1) { old=$5 } }'  | ttyplot -t "IN Bandwidth in KB/s" -u "KB/s" -c "#"

The script will do an infinite loop doing netstat -ibn every second and sending that output to awk. You can quit it with Ctrl+C.

Explanations

Netstat output contains total bytes (in or out) since system has started so awk needs to remember last value and will display the difference between two output, avoiding first value because it would make a huge spike (aka the total network transfered since boot time).

If I decompose the awk script, this is a lot more readable. Awk is very readable if you take care to format it properly as any source code!

#!/bin/sh
{ while :;
  do
      netstat -i -b -n
      sleep 1
  done
} | awk '
    BEGIN {
        old=-1
    }
    /^trunk0/ { 
        if(!index($4,":") && old>=0) {
            print ($5-old)/1024
            fflush
            old = $5
        }
        if(old==-1) {
            old = $5
        }
    }' | ttyplot -t "IN Bandwidth in KB/s" -u "KB/s" -c "#"

Customization

  • replace trunk0 by your interface name
  • replace both instances of $5 by $6 for OUT traffic
  • replace /1024 by /1048576 for MB/s values
  • remove /1024 for B/s values
  • replace 1 in sleep 1 by another value if you want to have the value every n seconds

IN/OUT version for both data on the same graph + simpler

Thanks to leot on IRC, netstat can be used in a lot more efficient way and remove all the awk parsing! ttyplot supports having two graphs at the same time, one being in opposite color.

netstat -b -w 1 -I trunk0 | awk 'NR>3 { print $1/1024; print $2/1024; fflush }' | ttyplot -2 -t "IN/OUT Bandwidth in KB/s" -u "KB/s" -c "#"

Streaming to Twitch using OpenBSD

Written by Solène, on 06 July 2019.
Tags: #openbsd #gaming

Comments on Fediverse/Mastodon

Introduction

If you ever wanted to make a twitch stream from your OpenBSD system, this is now possible, thanks to OpenBSD developer thfr@ who made a wrapper named fauxstream using ffmpeg with relevant parameters.

GitHub repository: fauxstream

The setup is quite easy, it only requires a few steps and searching on Twitch website two informations, hopefully, to ease the process, I found the links for you.

You will need to make an account on twitch, get your api key (a long string of characters) which should stay secret because it allow anyone having it to stream on your account.

Preparation steps

  1. Register / connect on twitch
  2. Get your Stream API key at https://www.twitch.tv/YOUR_USERNAME/dashboard/settings (from this page you can also choose if twitch should automatically saves streams as videos for 14 days)
  3. Choose your nearest server from this page
  4. Add in your shell environnement a variable TWITCH=rtmp://SERVER_FROM_STEP_3/YOUR_API_KEY
  5. Get fauxstream with cvs -d anoncvs@anoncvs.thfr.info:/cvs checkout -P projects/fauxstream/
  6. chmod u+x fauxstream/fauxstream
  7. Allow recording of the microphone
  8. Allow recording of the output sound

Once you have all the pieces, start a new shell and check the $TWITCH variable is correctly set, it should looks like rtmp://live-ams.twitch.tv/app/live_2738723987238_jiozjeoizaeiazheizahezah (this is not a real api key).

Using fauxstream

fauxstream script comes with a README.md file containing some useful informations, you can also check the usage

View usage:

$ ./fauxstream

Starting a stream

When you start a stream, take care your API key isn’t displayed on the stream! I redirect stderr to /dev/null so all the output containing the key is not displayed.

Here is the settings I use to stream:

$ ./fauxstream -m -vmic 5.0 -vmon 0.2 -r 1920x1080 -f 20 -b 4000 $TWITCH 2> /dev/null

If you choose a smaller resolution than your screen, imagine a square of that resolution starting at the top left corner of your screen, the content of this square will be streamed.

I recommend bwm-ng package (I wrote a ports of the week article about it) to view your realtime bandwidth usage, if you see the bandwidth reach a fixed number this mean you reached your bandwidth limit and the stream is certainly not working correctly, you should lower resolution, fps or bitrate.

I recommend doing a few tries before you want to stream, to be sure it’s ok. Note that the flag -a may be be required in case of audio/video desynchronization, there is no magic value so you should guess and try.

Adding webcam

I found an easy trick to add webcam on top of a video game.

$ mpv --no-config --video-sync=display-vdrop --framedrop=vo --ontop av://v4l2:/dev/video1

The trick is to use mpv to display your webcam video on your screen and use the flag to make it stay on top of any other window (this won’t work with cwm(1) window manager). Then you can resize it and place it where you want. What you see is what get streamed.

The others mpv flags are to reduce lag between the webcam video stream and the display, mpv slowly get a delay and after 10 minutes, your webcam will be lagging by like 10 seconds and will be totally out of sync between the action and your face.

Don’t forget to use chown to change the ownership of your video device to your user, by default only root has access to video devices. This is reset upon reboot.

Viewing a stream

For less overhead, people can watch a stream using mpv software, I think this will require youtube-dl package too.

Example to view me streaming:

$ mpv https://www.twitch.tv/seriphyde

This would also work with a recorded video:

$ mpv https://www.twitch.tv/videos/447271018

High quality / low latency VOIP server with umurmur/Mumble on OpenBSD

Written by Solène, on 04 July 2019.
Tags: #openbsd #gaming

Comments on Fediverse/Mastodon

Hello,

I HATE Discord.

Discord users keep telling about their so called discord server, which is not dedicated to them at all. And Discord has a very bad quality and a lot of voice distorsion.

Why not run your very own mumble server with high voice quality and low latency and privacy respect? This is very easy to setup on OpenBSD!

Mumble is an open source voip client, it has a client named Mumble (available on various operating system) and at least Android, the server part is murmur but there is a lightweight server named umurmur. People authentication is done through certificate generated locally and automatically accepted on a server, and the certificate get associated with a nickname. Nobody can pick the same nickname as another person if it’s not the same certificate.

How to install?

# pkg_add umurmur
# rcctl enable umurmurd
# cp /usr/local/share/examples/umurmur/umurmur.conf /etc/umurmur/

We can start it as this, you may want to tweak the configuration file to add a password to your server, or set an admin password, create static channels, change ports etc….

You may want to increase the max_bandwidth value to increase audio quality, or choose the right value to fit your bandwidth. Using umurmur on a DSL line is fine up to 1 or 2 remote people. The daemon uses very little CPU and very little memory. Umurmur is meant to be used on a router!

# rcctl start umurmurd

If you have a restrictive firewall (I hope so), you will have to open the ports TCP and UDP 64738.

How to connect to it?

The client is named Mumble and is packaged under OpenBSD, we need to install it:

# pkg_add mumble

The first time you run it, you will have a configuration wizard that will take only a couple of minutes.

Don’t forget to set the sysctl kern.audio.record to 1 to enable audio recording, as OpenBSD did disable audio input by default a few releases ago.

You will be able to choose a push-to-talk mode or voice level to activate and quality level.

Once the configuration wizard is done, you will have another wizard for generating the certificate. I recommend choosing “Automatically create a certificate”, then validate and it’s done.

You will be prompted for a server, click on “Add new”, enter the name server so you can recognized it easily, type its hostname / IP, its port and your nickname and click OK.

Congratulations, you are now using your own private VOIP server, for real!

Nginx and acme-client on OpenBSD

Written by Solène, on 04 July 2019.
Tags: #openbsd #nginx #automation

Comments on Fediverse/Mastodon

I write this blog post as I spent too much time setting up nginx and SSL on OpenBSD with acme-client, due to nginx being chrooted and not stripping path and not doing it easily.

First, you need to set up /etc/acme-client.conf correctly. Here is mine for the domain ports.perso.pw:

authority letsencrypt {
        api url "https://acme-v02.api.letsencrypt.org/directory"
        account key "/etc/acme/letsencrypt-privkey.pem"
}
    
domain ports.perso.pw {
        domain key "/etc/ssl/private/ports.key"
        domain full chain certificate "/etc/ssl/ports.fullchain.pem"
        sign with letsencrypt
}

This example is for OpenBSD 6.6 (which is current when I write this) because of Let’s encrypt API URL. If you are running 6.5 or 6.4, replace v02 by v01 in the api url

Then, you have to configure nginx this way, the most important part in the following configuration file is the location block handling acme-challenge request. Remember that nginx is in chroot /var/www so the path to acme directory is acme.

http {
    include       mime.types;
    default_type  application/octet-stream;
    index         index.html index.htm;
    keepalive_timeout  65;
    server_tokens off;
    
    upstream backendurl {
        server unix:tmp/plackup.sock;
    }
     
    server {
      listen       80;
      server_name ports.perso.pw;
        
      access_log logs/access.log;
      error_log  logs/error.log info;
         
      root /htdocs/;
        
      location /.well-known/acme-challenge/ {
          rewrite ^/.well-known/acme-challenge/(.*) /$1 break;
          root /acme;
      } 
        
      location / {
          return 301 https://$server_name$request_uri;
      }
    }
        
    server {
      listen 443 ssl;
      server_name ports.perso.pw;
      access_log logs/access.log;
      error_log logs_error.log info;
      root /htdocs/;
        
      ssl_certificate /etc/ssl/ports.fullchain.pem;
      ssl_certificate_key /etc/ssl/private/ports.key;
      ssl_protocols TLSv1.1 TLSv1.2;
      ssl_prefer_server_ciphers on;
      ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH";

      [... stuff removed ...]
    }
    
}

That’s all! I wish I could have find that on the Internet so I share it here.

OpenBSD as an IPv6 router

Written by Solène, on 13 June 2019.
Tags: #openbsd #networking

Comments on Fediverse/Mastodon

This blog post is an update (OpenBSD 6.5 at that time) of this very same article I published in June 2018. Due to rtadvd replaced by rad, this text was not useful anymore.

I subscribed to a VPN service from the french association Grifon (Grifon website[FR] to get an IPv6 access to the world and play with IPv6. I will not talk about the VPN service, it would be pointless.

I now have an IPv6 prefix of 48 bits which can theorically have 280 addresses.

I would like my computers connected through the VPN to let others computers in my network to have IPv6 connectivity.

On OpenBSD, this is very easy to do. If you want to provide IPv6 to Windows devices on your network, you will need one more.

In my setup, I have a tun0 device which has the IPv6 access and re0 which is my LAN network.

First, configure IPv6 on your lan:

# ifconfig re0 inet6 autoconf

that’s all, you can add a new line “inet6 autoconf” to your file /etc/hostname.if to get it at boot.

Now, we have to allow IPv6 to be routed through the differents interfaces of the router.

# sysctl net.inet6.ip6.forwarding=1

This change can be made persistent across reboot by adding net.inet6.ip6.forwarding=1 to the file /etc/sysctl.conf.

Automatic addressing

Now we have to configure the daemon rad to advertise the we are routing, devices on the network should be able to get an IPv6 address from its advertisement.

The minimal configuration of /etc/rad.conf is the following:

interface re0 {
    prefix 2a00:5414:7311::/48
}

In this configuration file we only define the prefix available, this is equivalent to a dhcp addresses range. Others attributes could provide DNS servers to use for example, see rad.conf man page.

Then enable the service at boot and start it:

# rcctl enable rad
# rcctl start rad

Tweaking resolv.conf

By default OpenBSD will ask for IPv4 when resolving a hostname (see resolv.conf(5) for more explanations). So, you will never have IPv6 traffic until you use a software which will request explicit IPv6 connection or that the hostname is only defined with a AAAA field.

# echo "family inet6 inet4" >> /etc/resolv.conf.tail

The file resolv.conf.tail is appended at the end of resolv.conf when dhclient modifies the file resolv.conf.

Microsoft Windows

If you have Windows systems on your network, they won’t get addresses from rad. You will need to deploy dhcpv6 daemon.

The configuration file for what we want to achieve here is pretty simple, it consists of telling what range we want to allow on DHCPv6 and a DNS server. Create the file /etc/dhcp6s.conf:

interface re0 {
    address-pool pool1 3600;
};
pool pool1 {
    range 2a00:5414:7311:1111::1000 to 2a00:5414:7311:1111::4000;
};
option domain-name-servers 2001:db8::35;

Note that I added “1111” into the range because it should not be on the same network than the router. You can replace 1111 by what you want, even CAFE or 1337 if you want to bring some fun to network engineers.

Now, you have to install and configure the service:

# pkg_add wide-dhcpv6
# touch /etc/dhcp6sctlkey
# chmod 400 /etc/dhcp6sctlkey
# echo SOME_RANDOM_CHARACTERS | openssl enc -base64 > /etc/dhcp6sctlkey
# echo "dhcp6s -c /etc/dhcp6s.conf re0" >> /etc/rc.local

The openbsd package wide-dhcpv6 doesn’t provide a rc file to start/stop the service so it must be started from a command line, a way to do it is to type the command in /etc/rc.local which is run at boot.

The openssl command is needed for dhcpv6 to start, as it requires a base64 string as a secret key in the file /etc/dhcp6sctlkey.

RSS feed for OpenBSD stable packages repository (made with XSLT)

Written by Solène, on 05 June 2019.
Tags: #openbsd #automation

Comments on Fediverse/Mastodon

I am happy to announce there is now a RSS feed for getting news in case of new packages available on my repository https://stable.perso.pw/

The file is available at https://stable.perso.pw/rss.xml.

I take the occasion of this blog post to explain how the file is generated as I did not find easy tool for this task, so I ended up doing it myself.

I choosed to use XSLT, which is not quite common. Briefly, XSLT allows to use some kind of XML template on a XML data file, this allow loops, filtering etc… It requires only two parts: the template and the data.

Simple RSS template

The following file is a template for my RSS file, we can see a few tags starting by xsl like xsl:for-each or xsl:value-of.

It’s interesting to note that the xsl-for-each can use a condition like position < 10 in order to limit the loop to the 10 first items.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    
<xsl:template match="/">
    <rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
        <channel>
            <description></description>
    
            <!-- BEGIN CONFIGURATION -->
            <title>OpenBSD unofficial stable packages repository</title>
            <link>https://stable.perso.pw/</link>
            <atom:link href="https://stable.perso.pw/rss.xml" rel="self" type="application/rss+xml" />
            <!-- END CONFIGURATION -->
    
            <!-- Generating items -->
            <xsl:for-each select="feed/news[position()&lt;10]">
            <item>
                <title>
                    <xsl:value-of select="title"/>
                </title>
                <description>
                    <xsl:value-of select="description"/>
                </description>
                <pubDate>
                    <xsl:value-of select="date"/>
                </pubDate>
            </item>
            </xsl:for-each>
    
        </channel>
    </rss>
</xsl:template>
</xsl:stylesheet>

Simple data file

Now, we need some data to use with the template. I’ve added a comment block so I can copy / paste it to add a new entry into the RSS easily. As the date is in a painful format to write for a human, I added to my Makefile starting the commands a call to a script replacing the string DATE by the current date with the correct format.

<feed>
<news>
    <title>www/mozilla-firefox</title>
    <description>Firefox 67.0.1</description>
    <date>Wed, 05 Jun 2019 06:00:00 GMT</date>
</news>
    
<!-- copy paste for a new item
<news>
    <title></title>
    <description></description>
    <date></date>
</news>
-->
</feed>

Makefile

I love makefiles, so I share it even if this one is really short.

all:
	sh replace_date.sh
	xsltproc template.xml news.xml | xmllint -format - | tee rss.xml
	scp rss.xml perso.pw:/home/stable/
    
clean:
	rm rss.xml

When I want to add an entry, I copy / paste the comment block in news.xml, add DATE, run make and it’s uploaded :)

The command xsltproc is available from the package libxslt on OpenBSD.

And then, after writing this, I realise that manually editing the result file rss.xml is as much work as editing the news.xml file and then process it with xslt… But I keep that blog post as this can be useful for more complicated cases. :)

Simple way to use ssh tunnels in scripts

Written by Solène, on 15 May 2019.
Tags: #ssh #automation

Comments on Fediverse/Mastodon

While writing a script to backup a remote database, I did not know how to handle a ssh tunnel inside a script correctly/easily. A quick internet search pointed out this link to me: https://gist.github.com/scy/6781836

While I’m not a huge fan of the ControlMaster solution which consists at starting a ssh connection with ControlMaster activated, and tell ssh to close it, and don’t forget to put a timeout on the socket otherwise it won’t close if you interrupt the script.

But I really enjoyed a neat solution which is valid for most of the cases:

$ ssh -f -L 5432:localhost:5432 user@host "sleep 5" && pg_dumpall -p 5432 -h localhost > file.sql

This will create a ssh connection and make it go to background because of -f flag, but it will close itself after the command is run, sleep 5 in this case. As we chain it quickly to a command using the tunnel, ssh will only stops when the tunnel is not used anymore, keeping it alive only the required time for the pg_dump command, not more. If we interrupt the script, I’m not sure ssh will stop immediately or only after it ran successfully the command sleep, in both cases ssh will stop correctly. There is no need to use a long sleep value because as I said previously, the tunnel will stay up until nothing uses it.

You should note that the ControlMaster way is the only reliable way if you need to use the ssh tunnel for multiples commands inside the script.

Kermit command line to fetch remote files through ssh

Written by Solène, on 15 May 2019.
Tags: #kermit

Comments on Fediverse/Mastodon

I previously wrote about Kermit for fetching remote files using a kermit script. I found that it’s possible to achieve the same with a single kermit command, without requiring a script file.

Given I want to download files from my remote server from the path /home/mirror/pub and that I’ve setup a kermit server on the other part using inetd:

File /etc/inetd.conf:

7878 stream tcp nowait solene /usr/local/bin/kermit-sshsub kermit-sshsub

I can make a ssh tunnel to it to reach it locally on port 7878 to download my files.

kermit -I -j localhost:7878 -C "remote cd /home/mirror/pub","reget /recursive .",close,EXIT

Some flags can be added to make it even faster, like -v 31 -e 9042. I insist on kermit because it’s super reliable and there are no security issues if running behind a firewall and accessed through ssh.

Fetching files can be stopped at any time, it supports very poor connection too, it’s really reliable. You can also skip files, because sometimes you need some file first and you don’t want to modify your script to fetch a specific file (this only works if you don’t have too many files to get of course because you can skip them only one by one).

Simple shared folder with Samba on OpenBSD 6.5

Written by Solène, on 15 May 2019.
Tags: #samba #openbsd

Comments on Fediverse/Mastodon

This article explains how to set up a simple samba server to have a CIFS / Windows shared folder accessible by everyone. This is useful in some cases but samba configuration is not straightforward when you need it for a one shot time or this particular case.

The important covered case here is that no user are needed. The trick comes from map to guest = Bad User configuration line in [global] section. This option will automatically map an unknown user or no provided user to the guest account.

Here is a simple /etc/samba/smb.conf file to share /home/samba to everyone, except map to guest and the shared folder, it’s the stock file with comments removed.

[global]
   workgroup = WORKGROUP
   server string = Samba Server
   server role = standalone server
   log file = /var/log/samba/smbd.%m
   max log size = 50
   dns proxy = no 
   map to guest = Bad User
    
[myfolder]
   browseable = yes
   path = /home/samba
   writable = yes
   guest ok = yes
   public = yes

If you want to set up this on OpenBSD, it’s really easy:

# pkg_add samba
# rcctl enable smbd nmbd
# vi /etc/samba/smb.conf (you can use previous config)
# mkdir -p /home/samba
# chown nobody:nobody /home/samba
# rcctl start smbd nmbd

And you are done.

Neomutt cheatsheet

Written by Solène, on 23 April 2019.
Tags: #neomutt #openbsd

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I switched from a homemade script using mblaze to neomutt (after being using mutt, alpine and mu4e) and it’s difficult to remember everything. So, let’s do a cheatsheet!

  • Mark as read: Ctrl+R
  • Mark to delete: d
  • Execute deletion: $
  • Tag a mail: t
  • Move a mail: s (for save, which is a copy + delete)
  • Save a mail: c (for copy)
  • Operation on tagged mails: ;[OP] with OP being the key for that operation, like ;d for deleting tagged emails or ;s for moving them

Operations on attachments

  • Save to file: s
  • Pipe to view as html: | and then w3m -T text/html
  • Pipe to view as picture: | and then feh -

Delete mails based on date

  • use T to enter a date range, format [before]-[after] with before/after being a DD/MM/YYYY format (YYYY is optional)
  • ~d 24/04- to mark mails after 24/04 of this year
  • ~d -24/04 to mark mails before 24/04 of this year
  • ~d 24/04-25/04 to mark mails between 24/04 and 25/04 (inclusive)
  • ;d to tell neomutt we want to delete marked mails
  • $ to make deletion happen

Simple config

Here is a simple config I’ve built to get Neomutt usable for me.

set realname = "Jane Doe"
set from = "jane@doe.com"
set smtp_url = "smtps://login@doe.com:465"
alias me Jane Doe <login@doe.com>
set folder = "imaps://login@doe.com:993"
set imap_user = "login"
set header_cache     = /home/solene/.cache/neomutt/jane/headers
set message_cachedir = /home/solene/.cache/neomutt/jane/bodies
set imap_pass = "xx"
set smtp_pass = "xx"

set imap_idle = yes       # IMAP push (supposed to work)
set mbox_type = Maildir
set ssl_starttls = yes
set ssl_force_tls = yes

set spoolfile = "+INBOX"
set record = "+Sent"
set postponed = "+Drafts"
set trash = "+Trash"
set imap_list_subscribed = yes
set imap_check_subscribed

#sidebar
set sidebar_visible
set sidebar_format = "%B%?F? [%F]?%* %?N?%N/?%S"
set mail_check_stats
bind index,pager \Cp sidebar-prev         # Ctrl-Shift-p - Previous Mailbox
bind index,pager \Cn sidebar-next         # Ctrl-Shift-n - Next Mailbox
bind index,pager \Ca sidebar-open         # Ctrl-Shift-a - Open Highlighted Mailbox
bind index "," imap-fetch-mail            # ,            - Get new emails
bind index,pager "N" next-unread-mailbox  # Jump to next unread email

# regroup by threads
set sort=threads

# display only interesting headers
ignore *
unignore from date subject to cc
unignore organization organisation x-mailer: x-newsreader: x-mailing-list:
unignore posted-to:

Create a dedicated user for ssh tunneling only

Written by Solène, on 17 April 2019.
Tags: #openbsd #ssh

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I use ssh tunneling A LOT, for everything. Yesterday, I removed the public access of my IMAP server, it’s now only available through ssh tunneling to access the daemon listening on localhost. I have plenty of daemons listening only on localhost that I can only reach through a ssh tunnel. If you don’t want to bother with ssh and redirect ports you need, you can also make a VPN (using ssh, openvpn, iked, tinc…) between your system and your server. I tend to avoid setting up VPN for the current use case as it requires more work and more maintenance than running ssh server and a ssh client.

The last change, for my IMAP server, added an issue. I want my phone to access the IMAP server but I don’t want to connect to my main account from my phone for security reasons. So, I need a dedicated user that will only be allowed to forward ports.

This is done very easily on OpenBSD.

The steps are:

  1. generate ssh keys for the new user
  2. add a user with no password
  3. allow public key for port forwarding

Obviously, you must allow users (or only this one) to make port forwarding in your sshd_config.

Generating ssh keys

Please generate the keys in a safe place, using ssh-keygen

$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:SOMETHINGSOMETHINSOMETHINSOMETHINSOMETHING user@myhost
The key's randomart image is:
+---[RSA 3072]----+
|                 |
| **              |
|  *     **  .    |
|  *     *        |
|  ****  *        |
|     ****        |
|                 |
|                 |
|                 |
+----[SHA256]-----+

This will create your public key in ~/.ssh/id_rsa.pub and the private key in ~/.ssh/id_rsa

Adding a user

On OpenBSD, we will create a user named tunnel, this is done with the following command as root:

# useradd -m tunnel

This user has no password and can’t login on ssh.

Allow the public key to port forward only

We will use the command restriction in the authorized_keys file to allow the previously generated key to only forward.

Edit /home/tunnel/.ssh/authorized_keys as following

command="echo 'Tunnel only!'" ssh-rsa PUT_YOUR_PUBLIC_KEY_HERE

This will tell “Tunnel only” and abort the connection if the user connects and with a shell or a command.

Connect using ssh

You can connect with ssh(1) as usual but you will require the flag -N to not start a shell on the remote server.

$ ssh -N -L 10000:localhost:993 tunnel@host

If you want the tunnel to stay up in the most automated way possible, you can use autossh from ports, which will do a great job at keeping ssh up.

$ autossh -M 0 -o "ExitOnForwardFailure yes" -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -o "TCPKeepAlive yes" -N -v -L 9993:localhost:993 tunnel@host

This command will start autossh, restart if forwarding doesn’t work which is likely to happens when you lose connectivity, it takes some time for the remote server to disable the forwarding effectively. It will make a keep alive check so the tunnel stays up and ensure it’s up (this is particularly useful on wireless connection like 4G/LTE).

The others flags are also ssh parameters, to not start a shell, and for making a local forwarding. Don’t forget that as a regular user, you can’t bind on ports less than 1024, that’s why I redirect the port 993 to the local port 9993 in the example.

Making the tunnel on Android

If you want to access your personal services from your Android phone, you can use ConnectBot ssh client. It’s really easy:

  1. upload your private key to the phone
  2. add it in ConnectBot from the main menu
  3. create a new connection the user and your remote host
  4. choose to use public key authentication and choose the registered key
  5. uncheck “start a shell session” (this is equivalent to -N ssh flag)
  6. from the main menu, long touch the connection and edit the forwarded ports

Enjoy!

Deploying munin-node with drist

Written by Solène, on 17 April 2019.
Tags: #drist #automation #openbsd

Comments on Fediverse/Mastodon

The following guide is a real world example of drist usage. We will create a script to deploy munin-node on OpenBSD systems.

We need to create a script that will install munin-node package but also configure it using the default proposal. This is done easily using the script file.

#!/bin/sh
    
# checking munin not installed
pkg_info | grep munin-node
if [ $? -ne 0 ]; then
    pkg_add munin-node
    munin-node-configure --suggest --shell | sh
    rcctl enable munin_node
fi
    
rcctl restart munin_node

The script contains some simple logic to prevent trying installing munin-node each time we will run it, and also prevent re-configuring it automatically every time. This is done by checking if pkg_info output contains munin-node.

We also need to provide a munin-node.conf file to allow our munin server to reach the nodes. For this how-to, I’ll dump the configuration in the commands using cat, but of course, you can use your favorite editor to create the file, or copy an original munin-node.conf file and edit it to suit your needs.

mkdir -p files/etc/munin/
    
cat <<EOF > files/etc/munin/munin-node.conf
log_level 4
log_file /var/log/munin/munin-node.log
pid_file /var/run/munin/munin-node.pid
background 1
setsid 1
user root
group wheel
ignore_file [\#~]$
ignore_file DEADJOE$
ignore_file \.bak$
ignore_file %$
ignore_file \.dpkg-(tmp|new|old|dist)$
ignore_file \.rpm(save|new)$
ignore_file \.pod$
allow ^127\.0\.0\.1$
allow ^192\.168\.1\.100$
allow ^::1$
host *
port 4949
EOF

Now, we only need to use drist on the remote host:

drist root@myserver

Last version of drist as now also supports privilege escalation using doas instead of connecting to root by ssh:

drist -s -e doas user@myserver

Playing Slay the Spire on OpenBSD

Written by Solène, on 01 April 2019.
Tags: #openbsd #gaming

Comments on Fediverse/Mastodon

Thanks to a hard work from thfr@, it is now possible to play the commercial game **Slay The Spire** on OpenBSD.

Small introduction to the game: it's a solo deck building game where you need to escalate a tower. Each floor may contain enemie(s) or a treasure or a merchant or an elite (harder enemies) or an event.

There are four characters playable, each unlocked after playing with the previous one. The game is really easy to understand, every game (or run) restart from the beginning with your character, at every new floor you may earn items and cards to build a deck for this run.

When you die, you can unlock some new items per characters and unlock cards for next runs. The goal is to reach the top of the tower. Each character is really different to play and each allow a few obvious deck builds.

The game work with an OpenBSD 6.5 minimum but this method using libgdx will work since 6.9. For this you will need:

  1. Buy Slay The Spire on GOG or Steam
  2. Copy files from a Slay The Spire installation (Windows or Linux) to your OpenBSD system or unzip the linux installer .sh file
  3. Install some packages with pkg_add: openal jdk-11 lwjgl libgdx
  4. Search for the .jar file (biggest file), then run libgdx-setup to extract data from the jar file and prepare the game.
  5. Run the game with libgdx-run
  6. Don't forget to eat, hydrate yourself and sleep. This game is time consuming :)

All settings and saves are stored in the game folder, so you may want to backup it if you don't want to lose your progression.

Again, thanks to thfr@ for his huge work on making games working on OpenBSD!

Using haproxy for TLS layer

Written by Solène, on 07 March 2019.
Tags: #openbsd

Comments on Fediverse/Mastodon

This article explains how to use haproxy to add a TLS layer to any TCP protocol. This includes http or gopher. The following example explains the minimal setup required in order to make it work, haproxy has a lot of options and I won’t use them.

The idea is to let haproxy manage the TLS part and let your http server (or any daemon listening on TCP) replying within the wrapped connection.

You need a simple haproxy.cfg which can looks like that:

defaults
        mode    tcp
        timeout client 50s
        timeout server 50s
        timeout connect 50s
    
frontend haproxy
        bind *:7000 ssl crt /etc/ssl/certificat.pem
        default_backend gopher
    
backend gopher
        server gopher 127.0.0.1:7070 check

The idea is that it waits on port 7000 and will use the file /etc/ssl/certificat.pem as a certificate, and forward requests to the backend on 127.0.0.1:7070. That is ALL. If you want to do https, you need to listen on port 443 and redirect to your port 80.

The PEM file is made from the privkey concatenated with the fullchain certificate. If you use a self signed certificate, you can make it with the following command:

cat secret.key certificate.crt > cert.pem

One can use a folder with PEM certificates files inside instead of using a file. This will allow haproxy to receive connections for ALL the certificates loaded.

For more security, I recommend using the chroot feature and a dh file but it’s out of the current topic.

Add a TLS layer to your Gopher server

Written by Solène, on 07 March 2019.
Tags: #gopher #openbsd

Comments on Fediverse/Mastodon

Hi,

In this article I will explain how to setup a gopher server supporting TLS. Gopher TLS support is not “official” as there is currently no RFC to define it. It has been recently chose by the community how to make it work, while keeping compatibility with old servers / clients.

The way to do it is really simple.

Client A tries to connects to Server B, Client A tries TLS handshake, if Server B answers correctly to the TLS handshakes, then Client A sends the gopher request and Server B answers the gopher requests. If Server B doesn’t understand the TLS handshakes, then it will probably output a regular gopher page, then this is throwed and Client A retries the connection using plaintext gopher and Server B answers the gopher request.

This is easy to achieve because gopher protocol doesn’t require the server to send anything to the client before the client sends its request.

The way to add the TLS layer and the dispatching can be achieved using sslh and relayd. You could use haproxy instead of relayd, but the latter is in OpenBSD base system so I will use it. Thanks parazyd for sharing about sslh for this use case.

sslh is a protocol demultiplexer, it listens on a port, and depending on what it receives, it will try to guess the protocol used by the client and send it to the according backend. It’s first purpose was to make ssh available on port 443 while still having https daemon working on that server.

Here is a schema of the setup

                        +→ relayd for TLS + forwarding
                        ↑                        ↓
                        ↑ tls?                   ↓
client -> sslh TCP 70 → +                        ↓
                        ↓ not tls                ↓
                        ↓                        ↓
                        +→ → → → → → → gopher daemon on localhost

This method allows to wrap any server to make it TLS compatible. The best case would be to have TLS compatibles servers which do all the work without requiring sslh and something to add the TLS. But it’s currently a way to show TLS for gopher is real.

Relayd

The relayd(1) part is easy, you first need a x509 certificate for the TLS part, I will not explain here how to get one, there are already plenty of how-to and one can use let’s encrypt with acme-client(1) to get one on OpenBSD.

We will write our configuration in /etc/relayd.conf

log connection
relay "gopher" {
    listen on 127.0.0.1 port 7000 tls
    forward to 127.0.0.1 port 7070
}

In this example, relayd listens on port 7000 and our gopher daemon listens on port 7070. According to relayd.conf(5), relayd will look for the certificate at the following places: /etc/ssl/private/$LISTEN_ADDRESS:$PORT.key and /etc/ssl/$LISTEN_ADDRESS:$PORT.crt, with the current example you will need the files: /etc/ssl/private/127.0.0.1:7000.key and /etc/ssl/127.0.0.1:7000.crt

relayd can be enabled and started using rcctl:

# rcctl enable relayd
# rcctl start relayd

Gopher daemon

Choose your favorite gopher daemon, I recommend geomyidae but any other valid daemon will work, just make it listening on the correct address and port combination.

# pkg_add geomyidae
# rcctl enable geomyidae
# rcctl set geomyidae flags -p 7070
# rcctl start geomyidae

SSLH

We will use sslh_fork (but sslh_select would be valid too, they have differents pros/cons). The --tls parameters tells where to forward a TLS connection while --ssh will forward to the gopher daemon. This is so because the protocol ssh is already configured within sslh and acts exactly like a gopher daemon: the client doesn’t expect the server to be the first sending data.

# pkg_add sslh
# rcctl enable sslh_fork
# rcctl set sslh_fork flags --tls 127.0.0.1:7000 --ssh 127.0.0.1:7070 -p 0.0.0.0:70
# rcctl start sslh_fork

Client

You can easily test if this works using openssl to connect by hand to the port 70

$ openssl s_client -connect 127.0.0.1:7000

You should see a lot of output, which is the TLS handshake, then you can send a gopher request like “/” and you should get a result. Using telnet on the same address and port should give the same result.

My gopher client clic already supports gopher TLS and is available at git://bitreich.org/clic and only requires the ecl common lisp interpreter to compile.

OpenBSD and iSCSI part2: the initiator (client)

Written by Solène, on 21 February 2019.
Tags: #unix #openbsd #iscsi

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This is the second article of the serie about iSCSI. In this one, you will learn how to connect to an iSCSI target using OpenBSD base daemon iscsid.

The configuration file of iscsid doesn’t exist by default, its location is /etc/iscsi.conf. It can be easily written using the following:

target1="100.64.2.3"
myaddress="100.64.2.2"

target "disk1" {
    initiatoraddr $myaddress
    targetaddr $target1
    targetname "iqn.1994-04.org.netbsd.iscsi-target:target0"
}

While most lines are really obvious, it is mandatory to have the line initiatoraddr, many thanks to cwen@ for pointing this out when I was stuck on it.

The targetname value will depend of the iSCSI target server. If you use netbsd-iscsi-target, then you only need to care about the last part, aka target0 and replace it by the name of your target (which is target0 for the default one).

Then we can enable the daemon and start it:

# rcctl enable iscsid
# rcctl start iscsid

In your dmesg, you should see a line like:

sd4 at scsibus0 targ 1 lun 0: <NetBSD, NetBSD iSCSI, 0> SCSI3 0/direct fixed t10.NetBSD_0x5c6cf1b69fc3b38a

If you use netbsd-iscsi-target, the whole line should be identic except for the sd4 part which can change, depending of your hardware.

If you don’t see it, you may need to reload iscsid configuration file with iscsictl reload.

Warning: iSCSI is a bit of pain to debug, if it doesn’t work, double check the IPs in /etc/iscsi.conf, check your PF rules on the initiator and the target. You should be at least able to telnet into the target IP port 3260.

Once you found your new sd device, you can format it and mount it as a regular disk device:

# newfs /dev/rsd4c
# mount /dev/sd4c /mnt

iSCSI is far mor efficient and faster than NFS but it has a total different purpose. I’m using it on my powerpc machines to build packages on it. This reduce their old IDE disks usage while giving better response time and equivalent speed.

OpenBSD and iSCSI part1: the target (server)

Written by Solène, on 21 February 2019.
Tags: #unix #openbsd #iscsi

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This is the first article of a series about iSCSI.

iSCSI is a protocol designed for sharing a block device across network as if it was a local disk. This doesn’t permit using that disk from multiples places at once though, except if you use a specific filesystem like GFS2 or OCFS2 (Linux only). In this article, we will learn how to create an iSCSI target, which is the “server” part of iSCSI, the target is the system holding the disk and making it available to others on the network.

OpenBSD does not have an target server in base, we will have to use net/netbsd-iscsi-target for this. The setup is really simple.

First, we obviously need to install the package and we will activate the daemon so it start automatically at boot, but don’t start it yet:

# pkg_add netbsd-iscsi-target
# rcctl enable iscsi_target

The configurations files are in /etc/iscsi/ folder, it contains files auths and targets. The default configuration files are the same. By looking at the source code, it seems that auths is used there but it seems to have no use at all. We will just overwrite it everytime we modify targets to keep them in sync.

Default /etc/iscsi/targets (with comments stripped):

extent0         /tmp/iscsi-target0      0       100MB
target0         rw      extent0         10.4.0.0/16

The first line defines the file holding our disk in the second field, and the last field defines the size of it. When iscsi-target will be started, it will create files as required with the size defined here.

The second line defines permissions, in that case, the extent0 disk can be used read/write by the net 10.4.0.0/16. For this example, I will only change the netmask to suit my network, then I copy targets over auths.

Let’s start the daemon:

# rcctl start iscsi_target
# rcctl check iscsi_target
iscsi_target(ok)

If you want to restrict ports using PF, you only have to allows the TCP port 3260 from the network that will connect to the target. The according line would looks like this:

pass in proto tcp to port 3260

Done!

Drist release with persistent ssh

Written by Solène, on 18 February 2019.
Tags: #unix #automation #drist

Comments on Fediverse/Mastodon

Drist see its release 1.04 available. This adds support for the flag -p to make the ssh connection persistent across the script using the ssh ControlMaster feature. This fixes one use case where you modify ssh keys in two operations: copy file + script to change permissions and this makes drist a lot faster for fast tasks.

Drist makes a first ssh connection to get the real hostname of the remote machine, and then will ssh for each step (copy, copy-hostname, absent, absent-hostname, script, script-hostname), this mean in the use case where you copy one file and reload a service, it was doing 3 connections. Now with the persistent flag, drist will keep the first connection and reusing it, closing the control socket at the end of the script.

Drist is now 121 lines long.

Download v1.04

SHA512 checksum, it is split it in two to not break the display:

525a7dc1362877021ad2db8025832048d4a469b72e6e534ae4c92cc551b031cd
1fd63c6fa3b74a0fdae86c4311de75dce10601d178fd5f4e213132e07cf77caa

Aspell to check spelling

Written by Solène, on 12 February 2019.
Tags: #unix

Comments on Fediverse/Mastodon

I never used a command line utility to check the spelling in my texts because I did not know how to do. After taking five minutes to learn how to do it, I feel guilty about not having used it before as it is really simple.

First, you want to install aspell package, which may be already there pulled as a dependency. In order to proceed on OpenBSD it’s easy:

# pkg_add aspell

I will only explain how to use it on text files. I think it is possible to have some integration with text editors but then, it would be more relevant to check out the editor documentation.

If I want to check the spelling in my file draft.txt it is as simple as:

$ aspell -l en_EN -c draft.txt

The parameter -l en_EN will depend of your locale, I have fr_FR.UTF-8 so aspell uses it by default if I don’t enforce another language. With this command, aspell will make an interactive display in the terminal

The output looks like this, with the word ful highlighted which I can not render in my article.

It's ful of mistakkes!
    
I dont know how to type corectly!
    
    
1) flu                                              6) FL
2) foul                                             7) fl
3) fuel                                             8) UL
4) full                                             9) fol
5) furl                                             0) fur
i) Ignore                                           I) Ignore all
r) Replace                                          R) Replace all
a) Add                                              l) Add Lower
b) Abort                                            x) Exit
    
?

I am asked how I want to resolve the issue with ful, as I wanted to write full, I will type 4 and aspell will replace the word ful with full. This will automatically jump to the next error found, mistakkes in my case:

It's full of mistakkes!
    
I dont know how to type corectly!
    
    
1) mistakes                                         6) misstates
2) mistake's                                        7) mistimes
3) mistake                                          8) mistypes
4) mistaken                                         9) stake's
5) stakes                                           0) Mintaka's
i) Ignore                                           I) Ignore all
r) Replace                                          R) Replace all
a) Add                                              l) Add Lower
b) Abort                                            x) Exit
    
?

and it will continue until there are no errors left, then the file is saved with the changes.

I will use aspell everyday from now.

Port of the week: sct

Written by Solène, on 07 February 2019.
Tags: #unix #openbsd

Comments on Fediverse/Mastodon

Long time I didn’t write a “port of the week”.

This week, I am happy to present you sct, a very small utility software to set the color of your screen. You can install it on OpenBSD with pkg_add sct and its usage is really simple, just run sct $temp where $temp is the temperature you want to get on your screen.

The default temperature is 6500, if you lower this value, the screen will change toward red, meaning your screen will appear less blue and this may be more comfortable for some people. The temperature you want to use depend from the screen and from your feeling, I have one screen which is correct at 5900 but another old screen which turn too much red below 6200!

You can add sct 5900 to your .xsession file to start it when you start your X11 session.

There is an alternative to sct whose name is redshift, it is more complicated as you need to tell it your location with latitude and longitude and, as a daemon, it will correct continuously your screen temperature depending on the time. This is possible because when you know your location on earth and the time, you can compute the sunrise time and dawn time. sct is not a daemon, you run it once and does not change the temperature until you call it again.

How to parallelize Drist

Written by Solène, on 06 February 2019.
Tags: #drist #automation #unix

Comments on Fediverse/Mastodon

This article will show you how to make drist faster by using it on multiple servers at the same time, in a correct way.

What is drist?

It is easily possible to parallelize drist (this works for everything though) using Makefile. I use this to deploy a configuration on my servers at the same time, this is way faster.

A simple BSD Make compatible Makefile looks like this:

SERVERS=tor-relay.local srvmail.tld srvmail2.tld
${SERVERS}:
        drist $*
install: ${SERVERS}
.PHONY: all install ${SERVERS}

This create a target for each server in my list which will call drist. Typing make install will iterate over $SERVERS list but it is so possible to use make -j 3 to tell make to use 3 threads. The output may be mixed though.

You can also use make tor-relay.local if you don’t want make to iterate over all servers. This doesn’t do more than typing drist tor-relay.local in the example, but your Makefile may do other logic before/after.

If you want to type make to deploy everything instead of make install you can add the line all: install in the Makefile.

If you use GNU Make (gmake), the file requires a small change:

The part ${SERVERS}: must be changed to ${SERVERS}: %:, I think that gmake will print a warning but I did not succeed with better result. If you have the solution to remove the warning, please tell me.

If you are not comfortable with Makefiles, the .PHONY line tells make that the targets are not valid files.

Make is awesome!

Vincent Delft talk at FOSDEM 2019: OpenBSD as a full-featured NAS

Written by Solène, on 05 February 2019.
Tags: #unix #openbsd

Comments on Fediverse/Mastodon

Hi, I rarely post about external links or other people work, but at FOSDEM 2019 Vincent Delft had a talk about running OpenBSD as a full featured NAS.

I do use OpenBSD on my NAS, I wanted to write an article about it since long time but never did it. Thanks to Vincent, I can just share his work which is very very interesting if you plan to make your own NAS.

Videos can be downloaded directly with following links provided by Fosdem:

Transfer your files with Kermit

Written by Solène, on 31 January 2019.
Tags: #unix #kermit

Comments on Fediverse/Mastodon

Hi, it’s been long time I wanted to write this article. The topic is Kermit, which is a file transfer protocol from the 80’s which solved problems of that era (text files and binaries files, poor lines, high latency etc..).

There is a comm/kermit package on OpenBSD and I am going to show you how to use it. The package is the program ckermit which is a client/server for kermit.

Kermit is a lot of things, there is a protocol, but it’s also the client/server, when you type kermit, it opens a kermit shell, where you can type commands or write kermit scripts. This allows scripts to be done using a kermit in the shebang.

I personally use kermit over ssh to retrieve files from my remote server, this requires kermit on both machines. My script is the following:

#!/usr/local/bin/kermit +
set host /pty ssh -t -e none -l solene perso.pw kermit
remote cd /home/ftp/
cd /home/solene/Downloads/
reget /recursive /delete .
close
exit

This connects to the remote server and starts kermit. It changes the current directory on the remote server into /home/ftp and locally it goes into /home/solene/Downloads, then, it start retrieving data, continuing previous transfer if not finished (reget command), for every file finished, it’s deleted on the remote server. Once finished, it close the ssh connection and exits.

The transfer interfaces looks like this. It shows how you are connected, which file is currently transferring, its size, the percent done (0% in the example), time left, speed and some others information.

C-Kermit 9.0.302 OPEN SOURCE:, 20 Aug 2011, solene.perso.local [192.168.43.56]
    
   Current Directory: /home/downloads/openbsd
        Network Host: ssh -t -e none -l solene perso.pw kermit (UNIX)
        Network Type: TCP/IP
              Parity: none
         RTT/Timeout: 01 / 03
           RECEIVING: src.tar.gz => src.tar.gz => src.tar.gz
           File Type: BINARY
           File Size: 183640885
        Percent Done:
                          ...10...20...30...40...50...60...70...80...90..100
 Estimated Time Left: 00:43:32
  Transfer Rate, CPS: 70098
        Window Slots: 1 of 30
         Packet Type: D
        Packet Count: 214
       Packet Length: 3998
         Error Count: 0
          Last Error:
        Last Message:
    
X to cancel file, Z to cancel group, <CR> to resend last packet,
E to send Error packet, ^C to quit immediately, ^L to refresh screen.

What’s interesting is that you can skip a file by pressing “X”, kermit will stop the downloading (but keep the file for later resuming) and start downloading the next file. It can be useful sometimes when you transfer a bunch of files, and it’s really big and you don’t want it now and don’t want to type the command by hand, just “X” and it skips it. Z or E will exists the transfer and close the connection.

Speed can be improved by adding the following lines before the reget command:

set reliable
set window 32
set receive packet-length 9024

This improves performance because nowadays our networks are mostly reliable and fast. Kermit was designed at a time when serial line was used to transfer data. It’s also reported that Kermit is in use in the ISS (International Space Station), I can’t verify if it’s still in use there.

I never had any issue while transferring, even by getting a file by resuming it so many times or using a poor 4G hot-spot with 20s of latency.

I did some tests and I get same performances than rsync over the Internet, it’s a bit slower over Lan though.

I only described an use case. Scripts can be made, there are a lot of others commands. You can type “help” in the kermit shell to get some hints for more help, “?” will display the command list.

It can be used interactively, you can queue files by using “add” to create a send-list, and then proceed to transfer the queue.

Another way to use it is to start the local kermit shell, then type “ssh user@remote-server” which will ssh into a remote box. Then you can type “kermit” and type kermit commands, this make a link between your local kermit and the remote one. You can go back to the local kermit by typing "Ctrl+", and go back to the remote by entering the command “C”.

This is a piece of software I found by lurking into the ports tree for discovering new software and I felt in love with it. It’s really reliable.

It does a different job compared to rsync, I don’t think it can preserve time, permissions etc… but it can be scripted completely, using parameters, and it’s an awesome piece of software!

It should support HTTP, HTTPS and ftp transfers too, as a client, but I did not get it work. On OpenBSD, the HTTPS support is disabled, it requires some work to switch to libreSSL.

You can find information on the official website.

Some 2019 news

Written by Solène, on 14 January 2019.
Tags: #blog

Comments on Fediverse/Mastodon

Hi from 2019! Some news about me and this blog.

It’s been more than a month since the last article, which is unusual. I don’t have much time these days and the ideas in the queue are not easy topics, so I don’t publish anything.

I am now on Mastodon at solene@bsd.network, publishing things on the Fediverse. Mostly UNIX propaganda.

This year I plan to work on reed-alert to improve its usage, maybe write more how-to or documentation about it too. I also think about writing non-core probes in a separate repository.

Cl-yag, the blog generator that I use for this blog should deserve some attention too, I would like to make it possible to create static pages not in the index/RSS, this doesn’t require much code as I already have a proof of concept, but it requires some changes to better integrate within.

Finally, my deployment tool drist should definitely be fixed to support tcsh and csh on remote shells for script execution. This requires a few easy changes. Some better documentation and how-to would be nice too.

I also revived a project named faubackup, it’s a backup software which is now hosted on Framagit.

And I revived another project which is from me, a packages statistics website to have some stats about installed OpenBSD packages. The code is not great, the web UI is not great, the filters are not great but it works. It needs improvements. I’m thinking about making a package of it for people wishing to participate, that would install the client and add a cron to update the package list weekly. The Web UI is at this address Pkgstat, that name is not good but I did not find a good name yet. The code can be downloaded here.

Thank you for reading :)

Fun tip #3: Split a line using ed

Written by Solène, on 04 December 2018.
Tags: #fun-tip #unix #openbsd

Comments on Fediverse/Mastodon

In this new article I will explain how to programmaticaly a line (with a newline) using ed.

We will use commands sent to ed in its stdin to do so. The logic is to locate the part where to add the newline and if a character need to be replaced.

this is a file
with a too much line in it that should be split
but not this one.

In order to do so, we will format using printf(1) the command list using a small trick to insert the newline. The command list is the following:

/too much line
s/that /that
,p

This search the first line matching “too much line” and then replaced "that " by "that0, the trick is to escape using a backslash so the substitution command can accept the newline, and at the end we print the file (replace ,n by w to write it).

The resulting command line is:

$ printf '/too much line0/that /that\0n0 | ed file.txt
81
> with a too much line in it that should be split
> should be split
> 1     this is a file
2       with a too much line in it that
3       should be split
4       but not this one.
> ?

Configuration deployment made easy with drist

Written by Solène, on 29 November 2018.
Tags: #unix #drist #automation

Comments on Fediverse/Mastodon

Hello, in this article I will present you my deployement tool drist (if you speak Russian, I am already aware of what you think). It reached a feature complete status today and now I can write about it.

As a system administrator, I started using salt a few years ago. And honestly, I can not cope with it anymore. It is slow, it can get very complicated for some tasks like correctly ordering commands and a configuration file can become a nightmare when you start using condition in it.

History

I also tried alternatives like ansible, puppet, Rex etc… One day, when lurking in the ports tree, I found sysutils/radmind which got a lot interest from me even if it is really poorly documented. It is a project from 1995 if I remember correctly, but I liked the base idea. Radmind works with files, you create a known working set of files for your system, and you can propagate that whole set to other machines, or see differences between the reference and the current system. Sets could be negative, meaning that the listed files should not be present on the system, but it was also possible to add extra sets for specific hosts. The whole thing is really really cumbersome, this requires a lot of work, I found little documentation etc… so I did not used it but, that lead me to write my own deployment tool using ideas from radmind (working with files) and from Rex (using a script for doing changes).

Concept

drist aims at being simple to understand and pluggable with standard tools. There is no special syntax to learn, no daemon to run, no agent, and it relies on base tools like awk, sed, ssh and rsync.

drist is cross platform as it has a few requirements but it is not well suited for deploying on too much differents operating systems.

When executed, drist will execute six steps in a specific order, you can use only steps you need.

Shamelessly copied from the man page, explanations after:

  1. If folder files exists, its content is copied to server rsync(1).
  2. If folder files-HOSTNAME exists, its content is copied to server using rsync(1).
  3. If folder absent exists, filenames in it are deleted on server.
  4. If folder absent-HOSTNAME exists, filenames in it are deleted on server.
  5. If file script exists, it is copied to server and executed there.
  6. If file script-HOSTNAME exists, it is copied to server and executed there.

In the previous list, all the existences checks are done from the current working directory where drist is started. The text HOSTNAME is replaced by the output of uname -n of the remote server, and files are copied starting from the root directory.

drist does not do anything more. In a more litteral manner, it copies files to the remote server, using a local filesystem tree (folder files). It will delete on the remote server all files present in the local filesystem tree (folder absent), and it will run on the remote server a script named script.

Each of theses can be customized per-host by adding a “-HOSTNAME” suffix to the folder or file name, because experience taught me that some hosts does require specific configuration.

If a folder or a file does not exist, drist will skip it. So it is possible to only copy files, or only execute a script, or delete files and execute a script after.

Drist usage

The usage is pretty simple. drist has 3 flags which are optionals.

  • -n flag will show what happens (simuation mode)
  • -s flag tells drist to use sudo on the remote host
  • -e flag with a parameter will tell drist to use a specific path for the sudo program

The remote server address (ssh format like user@host) is mandatory.

$ drist my_user@my_remote_host

drist will look at files and folders in the current directory when executed, this allow to organize as you want using your filesystem and a revision control system.

Simple examples

Here are two examples to illustrate its usage. The examples are easy, for learning purpose.

Deploying ssh keys

I want to easily copy my users ssh keys to a remote server.

$ mkdir drist_deploy_ssh_keys
$ cd drist_deploy_ssh_keys
$ mkdir -p files/home/my_user1/.ssh
$ mkdir -p files/home/my_user2/.ssh
$ cp -fr /path/to/key1/id_rsa files/home/my_user1/.ssh/
$ cp -fr /path/to/key2/id_rsa files/home/my_user2/.ssh/
$ drist user@remote-host
Copying files from folder "files":
	/home/my_user1/.ssh/id_rsa
	/home/my_user2/.ssh/id_rsa

Deploying authorized_keys file

We can easily create the authorized_key file by using cat.

$ mkdir drist_deploy_ssh_authorized
$ cd drist_deploy_ssh_authorized
$ mkdir -p files/home/user/.ssh/
$ cat /path/to/user/keys/*.pub > files/home/user/.ssh/authorized_keys
$ drist user@remote-host
Copying files from folder "files":
	/home/user/.ssh/authorized_keys

This can be automated using a makefile running the cat command and then running drist.

all:
	cat /path/to/keys/*.pub > files/home/user.ssh/authorized_keys
drist user@remote-host

Installing nginx on FreeBSD

This module (aka a folder which contain material for drist) will install nginx on FreeBSD and start it.

$ mkdir deploy_nginx
$ cd deploy_nginx
$ cat >script <<EOF
#!/bin/sh
test -f /usr/local/bin/nginx
if [ $? -ne 0 ]; then
	pkg install -y nginx
fi
sysrc nginx_enable=yes
service nginx restart
EOF
$ drist user@remote-host
Executing file "script":
	Updating FreeBSD repository catalogue...
	FreeBSD repository is up to date.
	All repositories are up to date.
	The following 1 package(s) will be affected (of 0 checked):
	
	New packages to be INSTALLED:
	        nginx: 1.14.1,2
	
	Number of packages to be installed: 1
	
	The process will require 1 MiB more space.
	421 KiB to be downloaded.
	[1/1] Fetching nginx-1.14.1,2.txz: 100%  421 KiB 430.7kB/s    00:01
	Checking integrity... done (0 conflicting)
	[1/1] Installing nginx-1.14.1,2...
	===> Creating groups.
	Using existing group 'www'.
	===> Creating users
	Using existing user 'www'.
	[1/1] Extracting nginx-1.14.1,2: 100%
	Message from nginx-1.14.1,2:
	
	===================================================================
	Recent version of the NGINX introduces dynamic modules support.  In
	FreeBSD ports tree this feature was enabled by default with the DSO
	knob.  Several vendor's and third-party modules have been converted
	to dynamic modules.  Unset the DSO knob builds an NGINX without
	dynamic modules support.
	
	To load a module at runtime, include the new `load_module'
	directive in the main context, specifying the path to the shared
	object file for the module, enclosed in quotation marks.  When you
	reload the configuration or restart NGINX, the module is loaded in.
	It is possible to specify a path relative to the source directory,
	or a full path, please see
	https://www.nginx.com/blog/dynamic-modules-nginx-1-9-11/ and
	http://nginx.org/en/docs/ngx_core_module.html#load_module for
	details.
	
	Default path for the NGINX dynamic modules is
	
	/usr/local/libexec/nginx.
	===================================================================
	nginx_enable:  -> yes
	Performing sanity check on nginx configuration:
	nginx: the configuration file /usr/local/etc/nginx/nginx.conf syntax is ok
	nginx: configuration file /usr/local/etc/nginx/nginx.conf test is successful
	nginx not running? (check /var/run/nginx.pid).
	Performing sanity check on nginx configuration:
	nginx: the configuration file /usr/local/etc/nginx/nginx.conf syntax is ok
	nginx: configuration file /usr/local/etc/nginx/nginx.conf test is successful
	Starting nginx.

More complex example

Now I will show more complexes examples, with host specific steps. I will not display the output because the previous output were sufficient enough to give a rough idea of what drist does.

Removing someone ssh access

We will reuse an existing module here, a user should not be able to login anymore on its account on the servers using the ssh key.

$ cd ssh
$ mkdir -p absent/home/user/.ssh/
$ touch absent/home/user/.ssh/authorized_keys
$ drist user@server

Installing php on FreeBSD

The following module will install php and remove the opcache.ini file, and will install php72-pdo_pgsql if it is run on server production.domain.private.

$ mkdir deploy_php && cd deploy_php
$ mkdir -p files/usr/local/etc
$ cp /some/correct/config.ini files/usr/local/etc/php.ini
$ cat > script <<EOF
#!/bin/sh
test -f /usr/local/etc/php-fpm.conf || pkg install -f php-extensions
sysrc php_fpm_enable=yes
service php-fpm restart
test -f /usr/local/etc/php/opcache.ini || rm /usr/local/etc/php/opcache.ini
EOF
$ cat > script-production.domain.private <<EOF
#!/bin/sh
test -f /usr/local/etc/php/pdo_pgsql.ini || pkg install -f php72-pdo_pgsql
service php-fpm restart
EOF

The monitoring machine

This one is unique and I would like to avoid applying its configuration against another server (that happened to me once with salt and it was really really bad). So I will just do all the job using the hostname specific cases.

$ mkdir my_unique_machine && cd my_unique_machine
$ mkdir -p files-unique-machine.private/usr/local/etc/{smokeping,munin}
$ cp /good/config files-unique-machine.private/usr/local/etc/smokeping/config
$ cp /correct/conf files-unique-machine.private/usr/local/etc/munin/munin.conf
$ cat > script-unique-machine.private <<EOF
#!/bin/sh
pkg install -y smokeping munin-master munin-node
munin-configure --shell --suggest | sh
sysrc munin_node_enable=yes
sysrc smokeping_enable=yes
service munin-node restart
service smokeping restart
EOF
$ drist user@incorrect-host
$ drist user@unique-machine.private
Copying files from folder "files-unique-machine.private":
	/usr/local/etc/smokeping/config
	/usr/local/etc/munin/munin.conf
Executing file "script-unique-machine.private":
    [...]

Nothing happened on the wrong system.

Be creative

Everything can be automated easily. I have some makefile in a lot of my drist modules, because I just need to type “make” to run it correctly. Sometimes it requires concatenating files before being run, sometimes I do not want to make mistake or having to remember on which module apply on which server (if it’s specific), so the makefile does the job for me.

One of my drist module will look at all my SSL certificates from another module, and make a reed-alert configuration file using awk and deploying it on the monitoring server. All I do is typing “make” and enjoy my free time.

How to get it and install it

  • Drist can be downloaded at this address.
  • Sources can be cloned using git clone git://bitreich.org/drist

In the sources folder, type “make install” as root, that will copy drist binary to /usr/bin/drist and its man page to /usr/share/man/man1/drist.1

For copying files, drist requires rsync on both local and remote hosts.

For running the script file, a sh compatible shell is required (csh is not working).

Fun tip #2: Display trailing spaces using ed

Written by Solène, on 29 November 2018.
Tags: #unix #fun-tip #openbsd

Comments on Fediverse/Mastodon

This second fun-tip article will explain how to display trailing spaces in a text file, using the ed(1) editor. ed has a special command for showing a dollar character at the end of each line, which mean that if the line has some spaces, the dollar character will spaced from the last visible line character.

$ echo ",pl" | ed some-file.txt
453
This second fun-tip article will explain how to display trailing$
spaces in a text file, using the$
[ed(1)$](https://man.openbsd.org/ed)
editor.$
ed has a special command for showing a dollar character at the end of$
each line, which mean that if the line has some spaces, the dollar$
character will spaced from the last visible line character.$
$
.Bd -literal -offset indent$
echo ",pl" | ed some-file.txt$

This is the output of the article file while I am writing it. As you can notice, there is no trailing space here.

The first number shown in the ed output is the file size, because ed starts at the end of the file and then, wait for commands.

If I use that very same command on a small text files with trailing spaces, the following result is expected:

49
this is full    $
of trailing  $
spaces      !    $

It is also possible to display line numbers using the “n” command instead of the “p” command. This would produce this result for my current article file:

1559
1       .Dd November 29, 2018$
2       .Dt "Show trailing spaces using ed"$
3       This second fun-tip article will explain how to display trailing$
4       spaces in a text file, using the$
5       .Lk https://man.openbsd.org/ed ed(1)$
6       editor.$
7       ed has a special command for showing a dollar character at the end of$
8       each line, which mean that if the line has some spaces, the dollar$
9       character will spaced from the last visible line character.$
10      $
11      .Bd -literal -offset indent$
12      echo ",pl" | ed some-file.txt$
13      453$
14      .Dd November 29, 2018
15      .Dt "Show trailing spaces using ed"
16      This second fun-tip article will explain how to display trailing
17      spaces in a text file, using the
18      .Lk https://man.openbsd.org/ed ed(1)
19      editor.
20      ed has a special command for showing a '\ character at the end of
21      each line, which mean that if the line has some spaces, the '\
22      character will spaced from the last visible line character.
23
24      \&.Bd \-literal \-offset indent
25      \echo ",pl" | ed some-file.txt
26      .Ed$
27      $
28      This is the output of the article file while I am writing it. As you$
29      can notice, there is no trailing space here.$
30      $
31      The first number shown in the ed output is the file size, because ed$
32      starts at the end of the file and then, wait for commands.$
33      $
34      If I use that very same command on a small text files with trailing$
35      spaces, the following result is expected:$
36      $
37      .Bd -literal -offset indent$
38      49$
39      this is full
40      of trailing
41      spaces      !
42      .Ed$
43      $
44      It is also possible to display line numbers using the "n" command$
45      instead of the "p" command.$
46      This would produce this result for my current article file:$
47      .Bd -literal -offset indent$

This shows my article file with each line numbered plus the position of the last character of each line, this is awesome!

I have to admit though that including my own article as example is blowing up my mind, especially as I am writing it using ed.

Tor part 6: onionshare for sharing files anonymously

Written by Solène, on 21 November 2018.
Tags: #tor #unix #networking #openbsd

Comments on Fediverse/Mastodon

If for some reasons you need to share a file anonymously, this can be done through Tor using the port net/onionshare. Onionshare will start a web server displaying an unique page with a list of shared files and a Download Files button leading to a zip file.

While waiting for a download, onionshare will display HTTP logs. By default, onionshare will exit upon successful download of the files but this can be changed with the flag –stay-open.

Its usage is very simple, execute onionshare with the list of files to share, as you can see in the following example:

solene@computer ~ $ onionshare Epictetus-The_Enchiridion.txt
Onionshare 1.3 | https://onionshare.org/
Connecting to the Tor network: 100% - Done
Configuring onion service on port 17616.
Starting ephemeral Tor onion service and awaiting publication
Settings saved to /home/solene/.config/onionshare/onionshare.json
Preparing files to share.
 * Running on http://127.0.0.1:17616/ (Press CTRL+C to quit)
Give this address to the person you're sending the file to:
http://3ngjewzijwb4znjf.onion/hybrid-marbled

Press Ctrl-C to stop server

Now, I need to give the address http://3ngjewzijwb4znjf.onion/hybrid-marbled to the receiver who will need a web browser with Tor to download it.

Tor part 5: onioncat for IPv6 VPN over tor

Written by Solène, on 13 November 2018.
Tags: #tor #unix #networking #openbsd

Comments on Fediverse/Mastodon

This article is about a software named onioncat, it is available as a package on most Unix and Linux systems. This software allows to create an IPv6 VPN over Tor, with no restrictions on network usage.

First, we need to install onioncat, on OpenBSD:

$ doas pkg_add onioncat

Run a tor hidden service, as explained in one of my previous article, and get the hostname value. If you run multiples hidden services, pick one hostname.

# cat /var/tor/ssh_hidden_service/hostname
g6adq2w15j1eakzr.onion

Now that we have the hostname, we just need to run ocat.

# ocat g6adq2w15j1eakzr.onion

If everything works as expected, a tun interface will be created. With a fe80:: IPv6 address assigned to it, and a fd87:: address.

Your system is now reachable, via Tor, through its IPv6 address starting with fd87:: . It supports every IP protocol. Instead of using torsocks wrapper and .onion hostname, you can use the IPv6 address with any software.

Moving away from Emacs, 130 days after

Written by Solène, on 13 November 2018.
Tags: #emacs

Comments on Fediverse/Mastodon

It has been more than four months since I wrote my article about leaving Emacs. This article will quickly speak about my journey.

First, I successfully left Emacs. Long story short, I like Emacs and think it’s a great piece of software, but I’m not comfortable being dependent of it for everything I do. I chose to replace all my Emacs usage by other software (agenda, notes taking , todo-list, IRC client, jabber client, editor etc..).

  • agenda is not replaced by when (port productivity/when), but I plan to replace it by calendar(1) as it’s in base and that when doesn’t do much.
  • todo-list: I now use taskwarrior + a kanban board (using kanboard) for team work
  • notes: I wrote a small software named “notes” which is a wrapper for editing files and following edition using git. It’s available at git://bitreich.org/notes
  • IRC: weechat (not better or worse than emacs circe)
  • jabber: profanity
  • editor: vim, ed or emacs, that depend what I do. Emacs is excellent for writing Lisp or Scheme code, while I prefer to use vim for most of edition task. I now use ed for small editions.
  • mail: I wrote some kind of a wrapper on top of mblaze. I plan to share it someday.

I’m happy to have moved out from Emacs.

Fun tip #1: Apply a diff with ed

Written by Solène, on 13 November 2018.
Tags: #fun-tip #unix #openbsd

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I am starting a new kind of articles that I chose to name it ”fun facts“. Theses articles will be about one-liners which can have some kind of use, or that I find interesting from a technical point of view. While not useless, theses commands may be used in very specific cases.

The first of its kind will explain how to programmaticaly use diff to modify file1 to file2, using a command line, and without a patch.

First, create a file, with a small content for the example:

$ printf "first line\nsecond line\nthird line\nfourth line with text\n" > file1
$ cp file1{,.orig}
$ printf "very first line\nsecond line\n third line\nfourth line\n" > file1

We will use diff(1) -e flag with the two files.

$ diff -e file1 file1.orig
4c
fourth line
.
1c
very first line
.

The diff(1) output is batch of ed(1) commands, which will transform file1 into file2. This can be embedded into a script as in the following example. We also add w as the last command in order to save the file after changes.

#!/bin/sh
ed file1 <<EOF
4c
fourth line
.
1c
very first line
.
w
EOF

This is a convenient way to transform a file into another file, without pushing the entire file. This can be used in a deployment script. This is less error prone than a sed command.

In the same way, we can use ed to alter configuration file by writing instructions without using diff(1). The following script will change the first line containing “Port 22” into Port 2222 in /etc/ssh/sshd_config.

#!/bin/sh
ed /etc/ssh/sshd_config <<EOF
/Port 22
c
Port 2222
.
w
EOF

The sed(1) equivalent would be:

sed -i'' 's/.*Port 22.*/Port 2222/' /etc/ssh/sshd_config

Both programs have their use, pros and cons. The most important is to use the right tool for the right job.

Play Stardew Valley on OpenBSD

Written by Solène, on 09 November 2018.
Tags: #gaming #openbsd

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It’s possible to play native Stardew Valley on OpenBSD, and it’s not using a weird trick!

First, you need to buy Stardew Valley, it’s not very expensive and is often available at a lower price. I recommend to buy it on GOG.

Now, follow the steps:

  1. install packages unzip and fnaify
  2. On GOG, download the linux installer
  3. unzip the installer (use unzip command on the .sh file)
  4. cd into data/noarch/game
  5. fnaify -y
  6. ./StardewValley

Enjoy!

Safely restrict commands through SSH

Written by Solène, on 08 November 2018.
Tags: #ssh #security #openbsd #highlight

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sshd(8) has a very nice feature that is often overlooked. That feature is the ability to allow a ssh user to run a specified command and nothing else, not even a login shell.

This is really easy to use and the magic happens in the file authorized_keys which can be used to restrict commands per public key.

For example, if you want to allow someone to run the “uptime” command on your server, you can create a user account for that person, with no password so the password login will be disabled, and add his/her ssh public key in ~/.ssh/authorized_keys of that new user, with the following content.

restrict,command="/usr/bin/uptime" ssh-rsa the_key_content_here

The user will not be able to log-in, and doing the command ssh remoteserver will return the output of uptime. There is no way to escape this.

While running uptime is not really helpful, this can be used for a much more interesting use case, like allowing remote users to use vmctl without giving a shell account. The vmctl command requires parameters, the configuration will be slightly different.

restrict,pty,command="/usr/sbin/vmctl $SSH_ORIGINAL_COMMAND" ssh-rsa the_key_content_here"

The variable SSH_ORIGINAL_COMMAND contains the value of what is passed as parameter to ssh. The pty keyword also make an appearance, that will be explained later.

If the user connects to ssh, vmctl with no parameter will be output.

$ ssh remotehost
usage:  vmctl [-v] command [arg ...]
    vmctl console id
    vmctl create "path" [-b base] [-i disk] [-s size]
    vmctl load "path"
    vmctl log [verbose|brief]
    vmctl reload
    vmctl reset [all|vms|switches]
    vmctl show [id]
    vmctl start "name" [-Lc] [-b image] [-r image] [-m size]
            [-n switch] [-i count] [-d disk]* [-t name]
    vmctl status [id]
    vmctl stop [id|-a] [-fw]
    vmctl pause id
    vmctl unpause id
    vmctl send id
    vmctl receive id

If you pass parameters to ssh, it will be passed to vmctl.

$ ssh remotehost show
   ID   PID VCPUS  MAXMEM  CURMEM     TTY        OWNER NAME
1     -     1    1.0G       -       -       solene test
$ ssh remotehost start test
vmctl: started vm 1 successfully, tty /dev/ttyp9
$ ssh -t remotehost console test
(I)nstall, (U)pgrade, (A)utoinstall or (S)hell?

The ssh connections become a call to vmctl and ssh parameters become vmctl parameters.

Note that in the last example, I use “ssh -t”, this is so to force allocation of a pseudo tty device. This is required for vmctl console to get a fully working console. The keyword restrict does not allow pty allocation, that is why we have to add pty after restrict, to allow it.

Tor part 4: run a relay

Written by Solène, on 08 November 2018.
Tags: #unix #tor

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In this fourth Tor article, I will quickly cover how to run a Tor relay, the Tor project already have a very nice and up-to-date Guide for setting a relay. Those relays are what make Tor usable, with more relay, Tor gets more bandwidth and it makes you harder to trace, because that would mean more traffic to analyze.

A relay server can be an exit node, which will relay Tor traffic to the outside. This implies a lot of legal issues, the Tor project foundation offers to help you if your exit node gets you in trouble.

Remember that being an exit node is optional. Most relays are not exit nodes. They will either relay traffic between relays, or become a guard which is an entry point to the Tor network. The guard gets the request over non-tor network and send it to the next relay of the user circuit.

Running a relay requires a lot of CPU (capable of some crypto) and a huge amount of bandwidth. Running a relay requires at least a bandwidth of 10Mb/s, this is a minimal requirement. If you have less, you can still run a bridge with obfs4 but I won’t cover it here.

When running a relay, you will be able to set a daily/weekly/monthly traffic limit, so your relay will stop relaying when it reach the quota. It’s quiet useful if you don’t have unmeasured bandwidth, you can also limit the bandwidth allowed to Tor.

To get real-time information about your relay, the software Nyx (net/nyx) is a Tor top-like front end which show Tor CPU usage, bandwidth, connections, log in real time.

The awesome Official Tor guide

File versioning with rcs

Written by Solène, on 31 October 2018.
Tags: #openbsd #highlight #unix #versioning

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In this article I will present you the rcs tools and we will use it for versioning files in /etc to track changes between editions. These tools are part of the OpenBSD base install.

Prerequisites

You need to create a RCS folder where your files are, so the files versions will be saved in it. I will use /etc in the examples, you can adapt to your needs.

# cd /etc
# mkdir RCS

The following examples use the command ci -u. This will be explained later why so.

Tracking a file

We need to add a file to the RCS directory so we can track its revisions. Each time we will proceed, we will create a new revision of the file which contain the whole file at that point of time. This will allow us to see changes between revisions, and the date of each revision (and some others informations).

I really recommend to track the files you edit in your system, or even configuration file in your user directory.

In next example, we will create the first revision of our file with ci, and we will have to write some message about it, like what is doing that file. Once we write the message, we need to validate with a single dot on the line.

# cd /etc
# ci -u fstab
fstab,v  <--  fstab
enter description, terminated with single '.' or end of file:
NOTE: This is NOT the log message!
>> this is the /etc/fstab file
>> .
initial revision: 1.1
done

Editing a file

The process of edition has multiples steps, using ci and co:

  1. checkout the file and lock it, this will make the file available for writing and will prevent using co on it again (due to lock)
  2. edit the file
  3. commit the new file + checkout

When using ci to store the new revision, we need to write a small message, try to use something clear and short. The log messages can be seen in the file history, that should help you to know which change has been made and why. The full process is done in the following example.

# co -l fstab
RCS/fstab,v  -->  fstab
revision 1.1 (locked)
done
# echo "something wrong" >> fstab
# ci -u fstab
RCS/fstab,v  <--  fstab
new revision: 1.4; previous revision: 1.3
enter log message, terminated with a single '.' or end of file:
>> I added a mistake on purpose!
>> .
revision 1.4 (unlocked)
done

View changes since last version

Using previous example, we will use rcsdiff to check the changes since the last version.

# co -l fstab
RCS/fstab,v  -->  fstab
revision 1.1 (locked)
done
# echo "something wrong" >> fstab
# rcsdiff -u fstab
--- fstab	2018/10/28 14:28:29	1.1
+++ fstab	2018/10/28 14:30:41
@@ -9,3 +9,4 @@
 52fdd1ce48744600.j /usr/src ffs rw,nodev,nosuid 1 2
 52fdd1ce48744600.e /var ffs rw,nodev,nosuid 1 2
 52fdd1ce48744600.m /data ffs rw,dev,wxallowed,nosuid 1 2
+something wrong

The -u flag is so to produce an unified diff, which I find easier to read. Lines with + shows additions, and lines with - show deletions (there are none in the example).

Use of ci -u

The examples were using ci -u this is because, if you use ci some_file, the file will be saved in the RCS folder but will be missing in its place. You should use co some_file to get it back (in read-only).

# co -l fstab
RCS/fstab,v  -->  fstab
revision 1.1 (locked)
done
# echo "something wrong" >> fstab
# ci -u fstab
RCS/fstab,v  <--  fstab
new revision: 1.4; previous revision: 1.3
enter log message, terminated with a single '.' or end of file:
>> I added a mistake on purpose!
>> .
done
# ls fstab
ls: fstab: No such file or directory
# co fstab
RCS/fstab,v  -->  fstab
revision 1.5
done
# ls fstab
fstab

Using ci -u is very convenient because it prevent the user to forget to checkout the file after commiting the changes.

Show existing revisions of a file

# rlog fstab
RCS file: RCS/fstab,v
Working file: fstab
head: 1.2
branch:
locks: strict
access list:
symbolic names:
keyword substitution: kv
total revisions: 2;     selected revisions: 2
description:
new file
----------------------------
revision 1.2
date: 2018/10/28 14:45:34;  author: solene;  state: Exp;  lines: +1 -0;
Adding a disk
----------------------------
revision 1.1
date: 2018/10/28 14:45:18;  author: solene;  state: Exp;
Initial revision
=============================================================================

We have revisions 1.1 and 1.2, if we want to display the file in its 1.1 revision, we can use the following command:

# co -p1.1 fstab
RCS/fstab,v  -->  standard output
revision 1.1
52fdd1ce48744600.b none swap sw
52fdd1ce48744600.a / ffs rw 1 1
52fdd1ce48744600.l /home ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.d /tmp ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.f /usr ffs rw,nodev 1 2
52fdd1ce48744600.g /usr/X11R6 ffs rw,nodev 1 2
52fdd1ce48744600.h /usr/local ffs rw,wxallowed,nodev 1 2
52fdd1ce48744600.k /usr/obj ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.j /usr/src ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.e /var ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.m /data ffs rw,dev,wxallowed,nosuid 1 2
done

Note that there is no space between the flag and the revision! This is required.

We can see that the command did output some extra informations about the file and “done” at the end of the file. Thoses extra informations are sent to stderr while the actual file content is sent to stdout. That mean if we redirect stdout to a file, we will get the file content.

# co -p1.1 fstab > a_file
RCS/fstab,v  -->  standard output
revision 1.1
done
# cat a_file
52fdd1ce48744600.b none swap sw
52fdd1ce48744600.a / ffs rw 1 1
52fdd1ce48744600.l /home ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.d /tmp ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.f /usr ffs rw,nodev 1 2
52fdd1ce48744600.g /usr/X11R6 ffs rw,nodev 1 2
52fdd1ce48744600.h /usr/local ffs rw,wxallowed,nodev 1 2
52fdd1ce48744600.k /usr/obj ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.j /usr/src ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.e /var ffs rw,nodev,nosuid 1 2
52fdd1ce48744600.m /data ffs rw,dev,wxallowed,nosuid 1 2

Show a diff of a file since a revision

We can use rcsdiff using -r flag to tell it to show the changes between last and one specific revision.

# rcsdiff -u -r1.1 fstab
--- fstab	2018/10/29 14:45:18	1.1
+++ fstab	2018/10/29 14:45:34
@@ -9,3 +9,4 @@
 52fdd1ce48744600.j /usr/src ffs rw,nodev,nosuid 1 2
 52fdd1ce48744600.e /var ffs rw,nodev,nosuid 1 2
 52fdd1ce48744600.m /data ffs rw,dev,wxallowed,nosuid 1 2
+something wrong

Configure OpenSMTPD to relay on a network

Written by Solène, on 29 October 2018.
Tags: #openbsd #highlight #opensmtpd

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With the new OpenSMTPD syntax change which landed with OpenBSD 6.4 release, changes are needed for making opensmtpd to act as a lan relay to a smtp server. This case wasn’t covered in my previous article about opensmtpd, I was only writing about relaying from the local machine, not for a network. Mike (a reader of the blog) shared that it would be nice to have an article about it. Here it is! :)

A simple configuration would look like the following:

listen on em0
listen on lo0
    
table aliases db:/etc/mail/aliases.db
table secrets db:/etc/mail/secrets.db
    
action "local" mbox alias <aliases>
action "relay" relay host smtps://myrelay@remote-smtpd.tld auth <secrets>
    
match for local action "local"
match from local for any action "relay"
match from src 192.168.1.0/24 for action relay

The daemon will listen on em0 interface, and mail delivered from the network will be relayed to remote-smtpd.tld.

For a relay using authentication, the login and passwords must be defined in the file /etc/mail/secrets like this: myrelay login:Pa$$W0rd

smtpd.conf(5) explains creation of /etc/mail/secrets like this:

touch /etc/mail/secrets
chmod 640 /etc/mail/secrets
chown root:_smtpd /etc/mail/secrets

Tor part 3: Tor Browser

Written by Solène, on 24 October 2018.
Tags: #openbsd #unix #tor

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In this third Tor article, we will discover the web browser Tor Browser.

The Tor Browser is an official Tor project. It is a modified Firefox, including some defaults settings changes and some extensions. The default changes are all related to privacy and anonymity. It has been made to be easy to browse the Internet through Tor without leaving behind any information which could help identify you, because there are much more information than your public IP address which could be used against you.

It requires tor daemon to be installed and running, as I covered in my first Tor article.

Using it is really straightforward.

How to install tor-browser

$ pkg_add tor-browser

How to start tor-browser

$ tor-browser

It will create a ~/TorBrowser-Data folder at launch. You can remove it as you want, it doesn’t contain anything sensitive but is required for it to work.

Show OpenSMTPD queue and force sending queued mails

Written by Solène, on 24 October 2018.
Tags: #opensmtpd #highlight #openbsd

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If you are using opensmtpd on a device not always connected on the internet, you may want to see what mail did not go, and force it to be delivered NOW when you are finally connected to the Internet.

We can use smtpctl to show the current queue.

$ doas smtpctl show queue
1de69809e7a84423|local|mta|auth|so@tld|dest@tld|dest@tld|1540362112|1540362112|0|2|pending|406|No MX found for domain

The previous command will report nothing if the queue is empty.

In the previous output, we see that there is one mail from me to dest@tld which is pending due to “NO MX found for domain” (which is normal as I had no internet when I sent the mail).

We need to extract the first field, which is 1de69809e7a84423 in the current example.

In order to tell opensmtpd to deliver it now, we will use the following command:

$ doas smtpctl schedule 1de69809e7a84423
1 envelope scheduled
$ doas smtpctl show queue

My mail was delivered, it’s not in the queue anymore.

If you wish to deliver all enveloppes in the queue, this is as simple as:

$ doas smtpctl schedule all

New cl-yag version

Written by Solène, on 12 October 2018.
Tags: #cl-yag #unix

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My website/gopherhole static generator cl-yag has been updated today, and see its first release!

New feature added today is that the gopher output now supports an index menu of tags, and a menu for each tags displaying articles tagged by that tag. The gopher output was a bit of a second class citizen before this, only listing articles.

New release v1.00 can be downloaded here (sha512 sum 53839dfb52544c3ac0a3ca78d12161fee9bff628036d8e8d3f54c11e479b3a8c5effe17dd3f21cf6ae4249c61bfbc8585b1aa5b928581a6b257b268f66630819). Code can be cloned with git: git://bitreich.org/cl-yag

Tor part 2: hidden service

Written by Solène, on 11 October 2018.
Tags: #openbsd #unix #tor #security

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In this second Tor article, I will present an interesting Tor feature named hidden service. The principle of this hidden service is to make available a network service from anywhere, with only prerequisites that the computer must be powered on, tor not blocked and it has network access.

This service will be available through an address not disclosing anything about the server internet provider or its IP, instead, a hostname ending by .onion will be provided by tor for connecting. This hidden service will be only accessible through Tor.

There are a few advantages of using hidden services:

  • privacy, hostname doesn’t contain any hint
  • security, secure access to a remote service not using SSL/TLS
  • no need for running some kind of dynamic dns updater

The drawback is that it’s quite slow and it only work for TCP services.

From here, we assume that Tor is installed and working.

Running an hidden service require to modify the Tor daemon configuration file, located in /etc/tor/torrc on OpenBSD.

Add the following lines in the configuration file to enable a hidden service for SSH:

HiddenServiceDir /var/tor/ssh_service
HiddenServicePort 22 127.0.0.1:22

The directory /var/tor/ssh_service will be be created. The directory /var/tor is owned by user _tor and not readable by other users. The hidden service directory can be named as you want, but it should be owned by user _tor with restricted permissions. Tor daemon will take care at creating the directory with correct permissions once you reload it.

Now you can reload the tor daemon to make the hidden service available.

$ doas rcctl reload tor

In the /var/tor/ssh_service directory, two files are created. What we want is the content of the file hostname which contains the hostname to reach our hidden service.

$ doas cat /var/tor/ssh_service/hostname
piosdnzecmbijclc.onion

Now, we can use the following command to connect to the hidden service from anywhere.

$ torsocks ssh piosdnzecmbijclc.onion

In Tor network, this feature doesn’t use an exit node. Hidden services can be used for various services like http, imap, ssh, gopher etc…

Using hidden service isn’t illegal nor it makes the computer to relay tor network, as previously, just check if you can use Tor on your network.

Note: it is possible to have a version 3 .onion address which will prevent hostname collapsing, but this produce very long hostnames. This can be done like in the following example:

HiddenServiceDir /var/tor/ssh_service
HiddenServicePort 22 127.0.0.1:22
HiddenServiceVersion 3

This will produce a really long hostname like tgoyfyp023zikceql5njds65ryzvwei5xvzyeubu2i6am5r5uzxfscad.onion

If you want to have the short and long hostnames, you need to specify twice the hidden service, with differents folders.

Take care, if you run a ssh service on your website and using this same ssh daemon on the hidden service, the host keys will be the same, implying that someone could theoricaly associate both and know that this public IP runs this hidden service, breaking anonymity.

Tor part 1: how-to use Tor

Written by Solène, on 10 October 2018.
Tags: #openbsd #unix #tor #security

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Tor is a network service allowing to hide your traffic. People sniffing your network will not be able to know what server you reach and people on the remote side (like the administrator of a web service) will not know where you are from. Tor helps keeping your anonymity and privacy.

To make it quick, tor make use of an entry point that you reach directly, then servers acting as relay not able to decrypt the data relayed, and up to an exit node which will do the real request for you, and the network response will do the opposite way.

You can find more details on the Tor project homepage.

Installing tor is really easy on OpenBSD. We need to install it, and start its daemon. The daemon will listen by default on localhost on port 9050. On others systems, it may be quite similar, install the tor package and enable the daemon if not enabled by default.

# pkg_add tor
# rcctl enable tor
# rcctl start tor

Now, you can use your favorite program, look at the proxy settings and choose “SOCKS” proxy, v5 if possible (it manage the DNS queries) and use the default address: 127.0.0.1 with port 9050.

If you need to use tor with a program that doesn’t support setting a SOCKS proxy, it’s still possible to use torsocks to wrap it, that will work with most programs. It is very easy to use.

# pkg_add torsocks
$ torsocks ssh remoteserver

This will make ssh going through tor network.

Using tor won’t make you relaying anything, and is legal in most countries. Tor is like a VPN, some countries has laws about VPN, check for your country laws if you plan to use tor. Also, note that using tor may be forbidden in some networks (companies, schools etc..) because this allows to escape filtering which may be against some kind of “Agreement usage” of the network.

I will cover later the relaying part, which can lead to legal uncertainty.

Note: as torsocks is a bit of a hack, because it uses LD_PRELOAD to wrap network system calls, there is a way to do it more cleanly with ssh (or any program supporting a custom command for initialize the connection) using netcat.

ssh -o ProxyCommand='/usr/bin/nc -X 5 -x 127.0.0.1:9050 %h %p' address.onion

This can be simplified by adding the following lines to your ~/.ssh/config file, in order to automatically use the proxy command when you connect to a .onion hostname:

Host *.onion
ProxyCommand='/usr/bin/nc -X 5 -x 127.0.0.1:9050 %h %p'

This netcat command is tested under OpenBSD, there are differents netcat implementations, the flags may be differents or may not even exist.

Create a new OpenBSD partition from unused space

Written by Solène, on 20 September 2018.
Tags: #openbsd #highlight

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The default OpenBSD partition layout uses a pre-defined template. If you have a disk more than 356 GB you will have unused space with the default layout (346 GB before 6.4).

It’s possible to create a new partition to use that space if you did not modify the default layout at installation. You only need to start disklabel with flag -E* and type a to add a partition, default will use all remaining space for the partition.

# disklabel -E sd0
Label editor (enter '?' for help at any prompt)
> a
partition: [m]
offset: [741349952]
size: [258863586]
FS type: [4.2BSD]
> w
> q
No label changes.

The new partition here is m. We can format it with:

# newfs /dev/rsd0m

Then, you should add it to your /etc/fstab, for that, use the same uuid as for other partitions, it would look something like 52fdd1ce48744600

52fdd1ce48744600.e /data ffs rw,nodev,nosuid 1 2

It will be auto mounted at boot, you only need to create the folder /data. Now you can do

# mkdir /data
# mount /data

and /data is usable right now.

You can read disklabel(8) and newfs for more informations.

Display the size of installed packages ordered by size

Written by Solène, on 11 September 2018.
Tags: #openbsd #highlight

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Simple command line to display your installed packages listed by size from smallest to biggest.

$ pkg_info -sa | paste - - - - | sort -n -k 5

Thanks to sthen@ for the command, I was previously using one involving awk which was less readable. paste is often forgotten, it has very specifics uses which can’t be mimic easily with other tools, its purpose is to joins multiples lines into one with some specific rules.

You can easily modify the output to convert the size from bytes to megabytes with awk:

$ pkg_info -sa | paste - - - - | sort -n -k 5 | awk '{ $NF=$NF/1024/1024 ; print }'

This divides the last element (using space separator) of each line twice by 1024 and displays the line.

News about the blog

Written by Solène, on 11 September 2018.
Tags: #highlight

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Today I will write about my blog itself. While I started it as my own documentation for some specific things I always forget about (like “How to add a route through a specific interface on FreeBSD”) or to publish my dot files, I enjoyed it and wanted to share about some specific topics.

Then I started the “port of the week” things, but as time goes, I find less of those software and so I don’t have anything to write about. Then, as I run multiples servers, sometimes when I feel that the way I did something is clean and useful, I share it here, as it is a reminder for me I also write it to be helpful for others.

Doing things right is time consuming, but I always want to deliver a polished write. In my opinion, doing things right includes the following:

  • explain why something is needed
  • explain code examples
  • give hints about potential traps
  • where to look for official documentation
  • provide environment informations like the operating system version used at the writing time
  • make the reader to think and get inspired instead of providing a material ready to be copy / pasted brainlessly

I try to keep as much as possible close to those guidelines. I even update from time to time my previous articles to check it still works on the latest operating system version, so the content is still relevant. And until it’s not updated, having the system version let the reader think about “oh, it may have changed” (or not, but it becomes the reader problem).

Now, I want to share about some OpenBSD specifics features, in a way to highlight features. In OpenBSD everything is documented correctly, but as a Human, one can’t read and understand every man page to know what is possible. Here come the highlighting articles, trying to show features, how to use it and where they are documented.

I hope you, reader, like what I write. I am writing here since two years and I still like it.

Manage ”nice” priority of daemons on OpenBSD

Written by Solène, on 11 September 2018.
Tags: #openbsd70 #openbsd #highlight

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Following a discussion on the OpenBSD mailing list misc, today I will write about how to manage the priority (as in nice priority) of your daemons or services.

In man page rc(8), one can read:

Before init(8) starts rc, it sets the process priority, umask, and
resource limits according to the “daemon” login class as described in
login.conf(5).  It then starts rc and attempts to execute the sequence of
commands therein.

Using /etc/login.conf we can manage some limits for services and daemon, using their rc script name.

For example, to make jenkins at lowest priority (so it doesn’t make troubles if it builds), using this line will set it to nice 20.

jenkins:priority=20

If you have a file /etc/login.conf.db you have to update it from /etc/login.conf using the software cap_mkdb. This creates a hashed database for faster information retrieval when this file is big. By default, that file doesn’t exist and you don’t have to run cap_mkdb. See login.conf(5) for more informations.

Configuration of OpenSMTPD to relay mails to outbound smtp server

Written by Solène, on 06 September 2018.
Tags: #openbsd70 #openbsd #opensmtpd #highlight

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In this article I will show how to configure OpenSMTPD, the default mail server on OpenBSD, to relay mail sent locally to your smtp server. In pratice, this allows to send mail through “localhost” by the right relay, so it makes also possible to send mail even if your computer isn’t connected to the internet. Once connected, opensmtpd will send the mails.

All you need to understand the configuration and write your own one is in the man page smtpd.conf(5). This is only a highlight on was it possible and how to achieve it.

In OpenBSD 6.4 release, the configuration of opensmtpd changed drasticaly, now you have to defines rules and action to do when a mail match the rules, and you have to define those actions.

In the following example, we will see two kinds of relay, the first is through smtp over the Internet, it’s the most likely you will want to setup. And the other one is how to relay to a remote server not allowing relaying from outside.

/etc/mail/smtpd.conf

table aliases file:/etc/mail/aliases
table secrets file:/etc/mail/secrets
listen on lo0
    
action "local" mbox alias <aliases>
action "relay" relay
action "myserver" relay host smtps://myrelay@perso.pw auth <secrets>
action "openbsd"  relay host localhost:2525
    
match mail-from "@perso.pw"    for any action "myserver"
match mail-from "@openbsd.org" for any action "openbsd"
match for local action "local"
match for any action "relay"

I defined 2 actions, one from “myserver”, it has a label “myrelay” and we use auth <secrets> to tell opensmtpd it needs authentication.

The other action is “openbsd”, it will only relay to localhost on port 2525.

To use them, I define 2 matching rules of the very same kind. If the mail that I want to send match the @domain-name, then choose relay “myserver” or “openbsd”.

The “openbsd” relay is only available when I create a SSH tunnel, binding the local port 25 of the remote server to my port 2525, with flags -L 2525:127.0.0.1:25.

For a relay using authentication, the login and passwords must be defined in the file /etc/mail/secrets like this: myrelay login:Pa$$W0rd

smtpd.conf(5) explains creation of /etc/mail/secrets like this:

touch /etc/mail/secrets
chmod 640 /etc/mail/secrets
chown root:_smtpd /etc/mail/secrets

Now, restarts your server. Then if you need to send mails, just use “mail” command or localhost as a smtp server. Depending on your From address, a different relay will be used.

Deliveries can be checked in /var/log/maillog log file.

See mails in queue

doas smtpctl show queue

Try to deliver now

doas smtpctl schedule all

Automatic switch wifi/ethernet on OpenBSD

Written by Solène, on 30 August 2018.
Tags: #openbsd70 #openbsd #networking #highlight

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Today I will cover a specific topic on OpenBSD networking. If you are using a laptop, you may switch from ethernet to wireless network from time to time. There is a simple way to keep the network instead of having to disconnect / reconnect everytime.

It’s possible to aggregate your wireless and ethernet devices into one trunk pseudo device in failover mode, which give ethernet the priority if connected.

To achieve this, it’s quite simple. If you have devices em0 and iwm0 create the following files.

/etc/hostname.em0

up

/etc/hostname.iwm0

join "office_network"  wpakey "mypassword"
join "my_home_network" wpakey "9charshere"
join "roaming phone"   wpakey "something"
join "Public Wifi"
up

/etc/hostname.trunk0

trunkproto failover trunkport em0 trunkport iwm0
autoconf

As you can see in the wireless device configuration we can specify multiples network to join, it is a new feature that will be available from 6.4 release.

You can enable the new configuration by running sh /etc/netstart as root.

This setup is explained in trunk(4) man page and in the OpenBSD FAQ as well.

Tmux mastery

Written by Solène, on 05 July 2018.
Tags: #unix #shell

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Tips for using Tmux more efficiently

Enter in copy mode

By default Tmux uses the emacs key-bindings, to make a selection you need to enter in copy-mode by pressing Ctrl+b and then [ with Ctrl+b being the tmux prefix key, if you changed it then do the replacement while reading.

If you need to quit the copy-mode, type Ctrl+C.

Make a selection

While in copy-mode, selects your start or ending position for your selection and then press Ctrl+Space to start the selection. Now, move your cursor to select the text and press Ctrl+w to validate.

Paste a selection

When you want to paste your selection, press Ctrl+b ] (you should not be in copy-mode for this!).

Make a rectangular selection

If you want to make a rectangular selection, press Ctrl+space to start and immediately, press R (capitalized R), then move your cursor and validate with Ctrl+w.

Output the buffer to X buffer

Make a selection to put the content in tmux buffer, then type

tmux save-buffer - | xclip

You may want to look at xclip (it’s a package) man page.

Output the buffer to a file

tmux save-buffer file

Load a file into buffer

It’s possible to load the content of a file inside the buffer for pasting it somewhere.

tmux load-buffer file

You can also load into the buffer the output of a command, using a pipe and - as a file like in this example:

echo 'something very interesting' | tmux load-buffer -

Display the battery percentage in the status bar

If you want to display your battery percentage and update it every 40 seconds, you can add two following lines in ~/.tmux.conf:

set status-interval 40
set -g status-right "#[fg=colour155]#(apm -l)%% | #[fg=colour45]%d %b %R"

This example works on OpenBSD using apm command. You can reuse this example to display others informations.

Writing an article using mdoc format

Written by Solène, on 03 July 2018.
Tags: #unix

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I never wrote a man page. I already had to read at the source of a man page, but I was barely understand what happened there. As I like having fun and discovering new things (people call me a Hipster since last days days ;-) ).

I modified cl-yag (the website generator used for this website) to be only produced by mdoc files. The output was not very cool as it has too many html items (classes, attributes, tags etc…). The result wasn’t that bad but it looked like concatenated man pages.

I actually enjoyed playing with mdoc format (the man page format on OpenBSD, I don’t know if it’s used somewhere else). While it’s pretty verbose, it allows to separate the formatting from the paragraphs. As I’m playing with ed editor last days, it is easier to have an article written with small pieces of lines rather than a big paragraph including the formatting.

Finally I succeded at writing a command line which produced an usable html output to use it as a converter in cl-yag. Now, I’ll be able to write my articles in the mdoc format if I want :D (which is fun). The convert command is really ugly but it actually works, as you can see if you read this.

cat data/%IN  | mandoc -T markdown | sed -e '1,2d' -e '$d' | multimarkdown -t html -o %OUT

The trick here was to use markdown as an convert format between mdoc to html. As markdown is very weak compared to html (in possibilities), it will only use simple tags for formatting the html output. The sed command is needed to delete the mandoc output with the man page title at the top, and the operating system at the bottom.

By having played with this, writing a man page is less obscure to me and I have a new unusual format to use for writing my articles. Maybe unusual for this use case, but still very powerful!

Trying to move away from emacs

Written by Solène, on 03 July 2018.
Tags: #unix #emacs

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Hello

Today I will write about my current process of trying to get rid of emacs. I use it extensively with org-mode for taking notes and making them into a agenda/todo-list, this helped me a lot to remember tasks to do and what people told to me. I also use it for editing of course, any kind of text or source code. This is usually the editor I use for writing the blog articles that you can read here. This one is written using ed. I also read my emails in emacs with mu4e (which last version doesn’t work anymore on powerpc due to a c++14 feature used and no compiler available on powerpc to compile it…).

While I like Emacs, I never liked to use one big tool for everything. My current quest is to look for a portable and efficient way to replace differents emacs parts. I will not stop using Emacs if the replacements are not good enough to do the job.

So, I identified my Emacs uses:

  • todo-list / agenda / taking notes
  • writing code (perl, C, php, Common LISP)
  • IRC
  • mails
  • writing texts
  • playing chess by mail
  • jabber client

I will try for each topic to identify alternatives and challenge them to Emacs.

Todo-list / Agenda / Notes taking

This is the most important part of my emacs use and it is the one I would really like to get out of Emacs. What I need is: writing quickly a task, add a deadline to it, add explanations or a description to it, be able to add sub-tasks for a task and be able to display it correctly (like in order of deadline with days / hours before deadline).

I am trying to convert my current todo-list to taskwarrior, the learning curve is not easy but after spending one hour playing with it while reading the man page, I have understood enough to replace org-mode with it. I do not know if it will be as good as org-mode but only time will let us know.

By the way, I found vit, a ncurses front-end for taskwarrior.

Writing code

Actually Emacs is a good editor. It supports syntax coloring, can evaluates regions of code (depend of the language), the editor is nice etc… I discovered jed which is a emacs-like editor written in C+libslang, it’s stable and light while providing more features than mg editor (available in OpenBSD base installation).

While I am currently playing with ed for some reasons (I will certainly write about it), I am not sure I could use it for writing a software from scratch.

IRC

There are lots of differents IRC clients around, I just need to pick up one.

Mails

I really enjoy using mu4e, I can find my mails easily with it, the query system is very powerful and interesting. I don’t know what I could use to replace it. I have been using alpine some times ago, and I tried mutt before mu4e and I did not like it. I have heard about some tools to manage a maildir folder using unix commands, maybe I should try this one. I did not any searches on this topic at the moment.

Writing text

For writing plain text like my articles or for using $EDITOR for differents tasks, I think that ed will do the job perfectly :-) There is ONE feature I really like in Emacs but I think it’s really easy to recreate with a script, the function bind on M-q to wrap a text to the correct column numbers!

Update: meanwhile I wrote a little perl script using Text::Wrap module available in base Perl. It wraps to 70 columns. It could be extended to fill blanks or add a character for the first line of a paragraph.

#!/usr/bin/env perl
use strict;use warnings;
use Text::Wrap qw(wrap $columns);
open IN, '<'.$ARGV[0];
$columns = 70;
my @file = <IN>;
print wrap("","",@file);

This script does not modify the file itself though.

Some people pointed me that Perl was too much for this task. I have been told about Groff or Par to format my files.

Finally, I found a very BARE way to handle this. As I write my text with ed, I added an new alias named “ruled” with spawn ed with a prompt of 70 characters #, so I have a rule each time ed displays its prompt!!! :D

It looks like this for the last paragraph:

###################################################################### c
been told about Groff or Par to format my files.
    
Finally, I found a very **BARE** way to handle this. As I write my
text with ed, I added an new alias named "ruled" with spawn ed with a
prompt of 70 characters #, so I have a rule each time ed displays its
prompt!!! :D
.
###################################################################### w

Obviously, this way to proceed only works when writing the content at first. If I need to edit a paragraph, I will need a tool to format correctly my document again.

Jabber client

Using jabber inside Emacs is not a very good experience. I switched to profanity (featured some times ago on this blog).

Playing Chess

Well, I stopped playing chess by mails, I am still waiting for my recipient to play his turn since two years now. We were exchanging the notation of the whole play in each mail, by adding our turn each time, I was doing the rendering in Emacs, but I do not remember exactly why but I had problems with this (replaying the string).

Easy encrypted backups on OpenBSD with base tools

Written by Solène, on 26 June 2018.
Tags: #unix #openbsd66 #openbsd

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Old article

Hello, it turned out that this article is obsolete. The security used in is not safe at all so the goal of this backup system isn’t achievable, thus it should not be used and I need another backup system.

One of the most important feature of dump for me was to keep track of the inodes numbers. A solution is to save the list of the inodes numbers and their path in a file before doing a backup. This can be achieved with the following command.

$ doas ncheck -f "\I \P\n" /var

If you need a backup tool, I would recommend the following:

Duplicity

It supports remote backend like ftp/sftp which is quite convenient as you don’t need any configuration on this other side. It supports compression and incremental backup. I think it has some GUI tools available.

Restic

It supports remote backend like cloud storage provider or sftp, it doesn’t require any special tool on the remote side. It supports deduplication of the files and is able to manage multiples hosts in the same repository, this mean that if you backup multiple computers, the deduplication will work across them. This is the only backup software I know allowing this (I do not count backuppc which I find really unusable).

Borg

It supports remote backend like ssh only if borg is installed on the other side. It supports compression and deduplication but it is not possible to save multiples hosts inside the same repository without doing a lot of hacks (which I won’t recommend).

Change default application for xdg-open

Written by Solène, on 25 June 2018.
Tags: #unix

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I write it as a note for me and if it can helps some other people, it’s fine.

To change the program used by xdg-open for opening some kind of file, it’s not that hard.

First, check the type of the file:

$ xdg-mime query filetype file.pdf
application/pdf

Then, choose the right tool for handling this type:

$ xdg-mime default mupdf.desktop application/pdf

Honestly, having firefox opening PDF files with GIMP IS NOT FUN.

Share a tmux session with someone with tmate

Written by Solène, on 01 June 2018.
Tags: #unix

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New port of the week, and it’s about tmate.

If you ever wanted to share a terminal with someone without opening a remote access to your computer, tmate is the right tool for this.

Once started, tmate will create a new tmux instance connected through the tmate public server, by typing tmate show-messages you will get url for read-only or read-write links to share with someone, by ssh or web browser. Don’t forget to type clear to hide url after typing show-messages, otherwise viewing people will have access to the write url (and it’s not something you want).

If you don’t like the need of a third party, you can setup your own server, but we won’t cover this in this article.

When you want to end the share, you just need to exit the tmux opened by tmate.

If you want to install it on OpenBSD, just type pkg_add tmate and you are done. I think it’s available on most unix systems.

There is no much more to say about it, it’s great, simple, work out-of-the-box with no configuration needed.

Deploying cron programmaticaly the unix way

Written by Solène, on 31 May 2018.
Tags: #unix

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Here is a little script to automatize in some way your crontab deployment when you don’t want to use a configuration tool like ansible/salt/puppet etc… This let you package a file in your project containing the crontab content you need, and it will add/update your crontab with that file.

The script works this way:

$ ./install_cron crontab_solene

with crontab_solene file being an actual crontab correct, which could looks like this:

## TAG ##
MAILTO=""
*/5 * * * *  ( cd ~/dev/reed-alert && ecl --load check.lisp )
*/10 * * * * /usr/local/bin/r2e run
1 * * * * vacuumdb -azf -U postgres
## END_TAG ##

Then it will include the file into my current user crontab, the TAG in the file is here to be able to remove it and replace it later with the new version. The script could be easily modified to support the tag name as parameter, if you have multiple deployments using the same user on the same machine.

Example:

$ crontab -l
0 * * * * pgrep iridium | xargs renice -n +20
$ ./install_cron crontab_solene
$ crontabl -l 
0 * * * * pgrep iridium | xargs renice -n +20
## TAG ##
MAILTO=""
*/5 * * * *  ( cd ~/dev/reed-alert && ecl --load check.lisp )
*/10 * * * * /usr/local/bin/r2e run
1 * * * * vacuumdb -azf -U postgres
## END_TAG ##

If I add to crontab_solene the line 0 20 * * * ~/bin/faubackup.sh I can now reinstall the crontab file.

$ crontabl -l 
0 * * * * pgrep iridium | xargs renice -n +20
## TAG ##
MAILTO=""
*/5 * * * *  ( cd ~/dev/reed-alert && ecl --load check.lisp )
*/10 * * * * /usr/local/bin/r2e run
1 * * * * vacuumdb -azf -U postgres
## END_TAG ##
$ ./install_cron crontab_solene
$ crontabl -l 
0 * * * * pgrep iridium | xargs renice -n +20
## TAG ##
MAILTO=""
*/5 * * * *  ( cd ~/dev/reed-alert && ecl --load check.lisp )
*/10 * * * * /usr/local/bin/r2e run
1 * * * * vacuumdb -azf -U postgres
0 20 * * * ~/bin/faubackup.sh
## END_TAG ##

Here is the script:

#!/bin/sh
    
if [ -z "$1" ]; then
    echo "Usage: $0 user_crontab_file"
    exit 1
fi
    
VALIDATION=0
grep "^## TAG ##$" "$1" >/dev/null
VALIDATION=$?
grep "^## END_TAG ##$" "$1" >/dev/null
VALIDATION=$(( VALIDATION + $? ))
    
if [ "$VALIDATION" -ne 0 ]
then
    echo "file ./${1} needs \"## TAG ##\" and \"## END_TAG ##\" to be used"
	exit 2
fi
    
crontab -l | \
    awk '{ if($0=="## TAG ##") { hide=1 };  if(hide==0) { print } ; if($0=="## END_TAG ##") { hide=0 }; }' | \
    cat - "${1}" | \
    crontab -

Mount a folder on another folder

Written by Solène, on 22 May 2018.
Tags: #openbsd70 #openbsd

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This article will explain quickly how to bind a folder to access it from another path. It can be useful to give access to a specific folder from a chroot without moving or duplicating the data into the chroot.

Real world example: “I want to be able to access my 100GB folder /home/my_data/ from my httpd web server chrooted in /var/www/”.

The trick on OpenBSD is to use NFS on localhost. It’s pretty simple.

# rcctl enable portmap nfsd mountd
# echo "/home/my_data -network=127.0.0.1 -mask=255.255.255.255" > /etc/exports
# rcctl start portmap nfsd mountd

The order is really important. You can check that the folder is available through NFS with the following command:

$ showmount -e
Exports list on localhost:
/home/my_data               127.0.0.1

If you don’t have any line after “Exports list on localhost:”, you should kill mountd with pkill -9 mountd and start mountd again. I experienced it twice when starting all the daemons from the same commands but I’m not able to reproduce it. By the way, mountd only supports reload.

If you modify /etc/exports, you only need to reload mountd using rcctl reload mountd.

Once you have check that everything was alright, you can mount the exported folder on another folder with the command:

# mount localhost:/home/my_data /var/www/htdocs/my_data

You can add -ro parameter in the /etc/exports file on the export line if you want it to be read-only where you mount it.

Note: On FreeBSD/DragonflyBSD, you can use mount_nullfs /from /to, there is no need to setup a local NFS server. And on Linux you can use mount --bind /from /to and some others ways that I won’t cover here.

Faster SSH with multiplexing

Written by Solène, on 22 May 2018.
Tags: #unix #ssh

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I discovered today an OpenSSH feature which doesn’t seem to be widely known. The feature is called multiplexing and consists of reusing an opened ssh connection to a server when you want to open another one. This leads to faster connection establishment and less processes running.

To reuse an opened connection, we need to use the ControlMaster option, which requires ControlPath to be set. We will also set ControlPersist for convenience.

  • ControlMaster defines if we create, or use or nothing about multiplexing
  • ControlPath defines where to store the socket to reuse an opened connection, this should be a path only available to your user.
  • ControlPersist defines how much time to wait before closing a ssh connection multiplexer after all connection using it are closed. By default it’s “no” and once you drop all connections the multiplexer stops.

I choosed to use the following parameters into my ~/.ssh/config file:

Host *
ControlMaster auto
ControlPath ~/.ssh/sessions/%h%p%r.sock
ControlPersist 60

This requires to have ~/.ssh/sessions/ folder restricted to my user only. You can create it with the following command:

install -d -m 700 ~/.ssh/sessions

(you can also do mkdir ~/.ssh/sessions && chmod 700 ~/.ssh/sessions but this requires two commands)

The ControlPath variable will creates sessions with the name “\({hostname}\){port}${user}.sock”, so it will be unique per remote server.

Finally, I choose to use ControlPersist to 60 seconds, so if I logout from a remote server, I still have 60 seconds to reconnect to it instantly.

Don’t forget that if for some reason the ssh channel handling the multiplexing dies, all the ssh connections using it will die with it.

Benefits with ProxyJump

Another ssh feature that is very useful is ProxyJump, it’s really useful to access ssh hosts which are not directly available from your current place. Like servers with no public ssh server available. For my job, I have a lot of servers not facing the internet, and I can still connect to them using one of my public facing server which will relay my ssh connection to the destination. Using the ControlMaster feature, the ssh relay server doesn’t have to handle lot of connections anymore, but only one.

In my ~/.ssh/config file:

Host *.private.lan
ProxyJump public-server.com

Those two lines allow me to connect to every servers with .private.lan domains (which is known by my local DNS server) by typing ssh some-machine.private.lan. This will establish a connection to public-server.com and then connects to the next server.

Sending mail with mu4e

Written by Solène, on 22 May 2018.
Tags: #unix #emacs

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In my article about mu4e I said that I would write about sending mails with it. This will be the topic covered in this article.

There are a lot of ways to send mails with a lot of differents use cases. I will only cover a few of them, the documentation of mu4e and emacs are both very good, I will only give hints about some interestings setups.

I would thank Raphael who made me curious about differents ways of sending mails from mu4e and who pointed out some mu4e features I wasn’t aware of.

Send mails through your local server

The easiest way is to send mails through your local mail server (which should be OpenSMTPD by default if you are running OpenBSD). This only requires the following line to works in your ~/.emacs file:

(setq message-send-mail-function 'sendmail-send-it)

Basically, it would be only relayed to the recipient if your local mail is well configured, which is not the case for most servers. This requires a reverse DNS address correctly configured (assuming a static IP address), a SPF record in your DNS and a DKIM signing for outgoing mail. This is the minimum to be accepted to others SMTP servers. Usually people send mails from their personal computer and not from the mail server.

Configure OpenSMTPD to relay to another smtp server

We can bypass this problem by configuring our local SMTP server to relay our mails sent locally to another SMTP server using credentials for authentication.

This is pretty easy to set-up, by using the following /etc/mail/smtpd.conf configuration, just replace remoteserver by your server.

table aliases file:/etc/mail/aliases
table secrets file:/etc/mail/secrets
  
listen on lo0
  
accept for local alias <aliases> deliver to mbox
accept for any relay via secure+auth://label@remoteserver:465 auth <secrets>

You will have to create the file /etc/mail/secrets and add your credentials for authentication on the SMTP server.

From smtpd.conf(5) man page, as root:

# touch /etc/mail/secrets
# chmod 640 /etc/mail/secrets
# chown root:_smtpd /etc/mail/secrets
# echo "label username:password" > /etc/mail/secrets

Then, all mail sent from your computer will be relayed through your mail server. With 'sendmail-send-it, emacs will delivered the mail to your local server which will relay it to the outgoing SMTP server.

SMTP through SSH

One setup I like and I use is to relay the mails directly to the outgoing SMTP server, this requires no authentication except a SSH access to the remote server.

It requires the following emacs configuration in ~/.emacs:

(setq
  message-send-mail-function 'smtpmail-send-it
  smtpmail-smtp-server "localhost"
  smtpmail-smtp-service 2525)

The configuration tells emacs to connect to the SMTP server on localhost port 2525 to send the mails. Of course, no mail daemon runs on this port on the local machine, it requires the following ssh command to be able to send mails.

$ ssh -N -L 127.0.0.1:2525:127.0.0.1:25 remoteserver

This will bind the port 127.0.0.1:25 from the remote server point of view on your address 127.0.0.1:2525 from your computer point of view.

Your mail server should accept deliveries from local users of course.

SMTP authentication from emacs

It’s also possible to send mails from emacs using a regular smtp authentication directly from emacs. It is boring to setup, it requires putting credentials into a file named ~/.authinfo that it’s possible to encrypt using GPG but then it requires a wrapper to load it. It also requires to setup correctly the SMTP authentication. There are plenty of examples for this on the Internet, I don’t want to cover it.

Queuing mails for sending it later

Mu4e supports a very nice feature which is mail queueing from smtpmail emacs client. To enable it, it requires two easy steps:

In ~/.emacs:

(setq
  smtpmail-queue-mail t
  smtpmail-queue-dir "~/Mail/queue/cur")

In your shell:

$ mu mkdir ~/Mail/queue
$ touch ~/Mail/queue/.noindex

Then, mu4e will be aware of the queueing, in the home screen of mu4e, you will be able to switch from queuing to direct sending by pressing m and flushing the queue by pressing f.

Note: there is a bug (not sure it’s really a bug). When sending a mail into the queue, if your mail contains special characters, you will be asked to send it raw or to add a header containing the encoding.

Autoscrolling text for lazy reading

Written by Solène, on 17 May 2018.
Tags: #unix

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Today I found a software named Lazyread which can read and display file an autoscroll at a chosen speed. I had to read its source code to make it work, the documentation isn’t very helpful, it doesn’t read ebooks (as in epub or mobi format) and doesn’t support stdin… This software requires some C code + a shell wrapper to works, it’s complicated for only scrolling.

So, after thinking a few minutes, the autoscroll can be reproduced easily with a very simple awk command. Of course, it will not have the interactive keys like lazyread to increase/decrease speed or some others options, but the most important part is there: autoscrolling.

If you want to read a file with a rate of 1 line per 700 millisecond, just type the following command:

$ awk '{system("sleep 0.7");print}' file

Do you want to read an html file (documentation file on the disk or from the web), you can use lynx or w3m to convert the html file on the fly to a readable text and pass it to awk stdin.

$ w3m -dump doc/slsh/slshfun-2.html | awk '{system("sleep 0.7");print}'
$ lynx -dump doc/slsh/slshfun-2.html | awk '{system("sleep 0.7");print}'
$ w3m -dump https://dataswamp.org/~solene/ | awk '{system("sleep 0.7");print}'

Maybe you want to read a man page?

$ man awk | awk '{system("sleep 0.7");print}'

If you want to pause the reading, you can use the true unix way, Ctrl+Z to send a signal which will stop the command and let it paused in background. You can resume the reading by typing fg.

One could easily write a little script parsing parameters for setting the speed or handling files or url with the correct command.

Notes: If for some reasons you try to use lazyread, fix the shebang in the file lesspipe.sh and you will need to call lazyread binary with the environment variable LESSOPEN="|./lesspipe.sh %s" (the path of the script if needed). Without this variable, you will have a very helpful error “file not found”.

Port of the week: Sent

Written by Solène, on 15 May 2018.
Tags: #unix

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As the new port of the week, We will discover Sent. While we could think it is mail related, it is not. Sent is a nice software to make presentations from a simple text file. It has been developped by Suckless, a hacker community enjoying writing good software while keeping a small and sane source code, they also made software like st, dwm, slock, surf…

Sent is about simplicity. I will reuse a part of the example file which is also the documentation of the tool.

usage:
$ sent FILE1 [FILE2 …]
    
▸ one slide per paragraph
▸ lines starting with # are ignored
▸ image slide: paragraph containing @FILENAME
▸ empty slide: just use a \ as a paragraph

@nyan.png
this text will not be displayed, since the @ at the start of the first line
makes this paragraph an image slide.

The previous text, saved into a file and used with sent will open a fullscreen window containg three “slides”. Each slide will resize the text to maximize the display usage, this mean the font size will change on each slide.

It is really easy to use. To display next slide, you have the choice between pressing space, right arrow, return or clicking any button. Pressing left arrow will go back.

If you want to install it on OpenBSD: pkg_add sent, the package comes from the port misc/sent.

Be careful, Sent does not produce any file, you will need it for the presentation!

Suckless sent website

Use ramdisk on /tmp on OpenBSD

Written by Solène, on 08 May 2018.
Tags: #openbsd70 #openbsd

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If you have enough memory on your system and that you can afford to use a few hundred megabytes to store temporary files, you may want to mount a mfs filesystem on /tmp. That will help saving your SSD drive, and if you use an old hard drive or a memory stick, that will reduce your disk load and improve performances. You may also want to mount a ramdisk on others mount points like ~/.cache/ or a database for some reason, but I will just explain how to achieve this for /tmp with is a very common use case.

First, you may have heard about tmpfs, but it has been disabled in OpenBSD years ago because it wasn’t stable enough and nobody fixed it. So, OpenBSD has a special filesystem named mfs, which is a FFS filesystem on a reserved memory space. When you mount a mfs filesystem, the size of the partition is reserved and can’t be used for anything else (tmpfs, as the same on Linux, doesn’t reserve the memory).

Add the following line in /etc/fstab (following fstab(5)):

swap /tmp mfs rw,nodev,nosuid,-s=300m 0 0

The permissions of the mountpoint /tmp should be fixed before mounting it, meaning that the /tmp folder on / partition should be changed to 1777:

# umount /tmp
# chmod 1777 /tmp
# mount /tmp

This is required because mount_mfs inherits permissions from the mountpoint.

Mounting remote samba share through SSH tunnel

Written by Solène, on 04 May 2018.
Tags: #unix

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If for some reason you need to access a Samba share outside of the network, it is possible to access it through ssh and mount the share on your local computer.

Using the ssh command as root is required because you will bind local port 139 which is reserved for root:

# ssh -L 139:127.0.0.1:139 user@remote-server -N

Then you can mount the share as usual but using localhost instead of remote-server.

Example of a mount element for usmb

<mount id="public" credentials="me">
   <server>127.0.0.1</server>
   <!--server>192.168.12.4</server-->
   <share>public</share>
   <mountpoint>/mnt/share</mountpoint>
   <options>allow_other,uid=1000</options>
</mount>

As a reminder, <!--tag>foobar</tag--> is a XML comment.

Extract files from winmail.dat

Written by Solène, on 02 May 2018.
Tags: #unix #email

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If you ever receive a mail with an attachment named “winmail.dat” then you may be disappointed. It is a special format used by Microsoft Exchange, it contains the files attached to the mail and need some specific software to extract them.

Hopefully, there is a simple and effecient utility named tnef to extract the files.

Install it: pkg_add tnef

List files: tnef -t winmail.dat

Extract files: tnef winmail.dat

That’s all!

Port of the week: ledger

Written by Solène, on 02 May 2018.
Tags: #unix

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In this post I will do a short presentation of the port productivity/ledger, an very powerful command line accounting software, using plain text as back-end. Writing on it is not an easy task, I will use a real life workflow of my usage as material, even if my use is special.

As I said before, Ledger is very powerful. It can helps you manage your bank accounts, bills, rents, shares and others things. It uses a double entry system which means each time you add an operation (withdraw, paycheck, …) , this entry will also have to contain the current state of the account after the operation. This will be checked by ledger by recalculating every operations made since it has been initialized with a custom amount as a start. Ledger can also tracks categories where you spend money or statistics about your payment method (check, credit card, bank transfer, money…).

As I am not an english native speaker and that I don’t work in banks or related, I am not very familiar with accounting words in english, it makes me very hard to understand all ledger keywords, but I found a special use case for accounting things and not money which is really practical.

My special use case is that I work from home for a company working in a remote location. From time to time, I take the train to the to the office, the full travel is

[home]   → [underground A] → [train] → [underground B] → [office]
[office] → [underground B] → [train] → [underground A] → [home]

It means I need to buy tickets for both underground A and underground B system, and I want to track tickets I use for going to work. I buy the tickets 10 by 10 but sometimes I use it for my personal use or sometimes I give a ticket to someone. So I need to keep track of my tickets to know when I can give a bill to my work for being refunded.

Practical example: I buy 10 tickets of A, I use 2 tickets at day 1. On day 2, I give 1 ticket to someone and I use 2 tickets in the day for personal use. It means I still have 5 tickets in my bag but, from my work office point of view, I should still have 8 tickets. This is what I am tracking with ledger.

2018/02/01 * tickets stock Initialization + go to work
    Tickets:inv                                   10 City_A
    Tickets:inv                                   10 City_B
    Tickets:inv                                   -2 City_A
    Tickets:inv                                   -2 City_B
    Tickets
    
2018/02/08 * Work
    Tickets:inv                                    -2 City_A
    Tickets:inv                                    -2 City_B
    Tickets
    
2018/02/15 * Work + Datacenter access through underground
    Tickets:inv                                    -4 City_B
    Tickets:inv                                    -2 City_A
    Tickets

At the point, running ledger -f tickets.dat balance Tickets shows my tickets remaining:

4 City_A
2 City_B  Tickets:inv

Will add another entry which requires me to buy tickets:

2018/02/22 * Work + Datacenter access through underground
    Tickets:inv                                    -4 City_B
    Tickets:inv                                    -2 City_A
    Tickets:inv                                    10 City_B
    Tickets

Now, running ledger -f tickets.dat balance Tickets shows my tickets remaining:

2 City_A
8 City_B  Tickets:inv

I hope that the example was clear enought and interesting. There is a big tutorial document available on the ledger homepage, I recommend to read it before using ledger, it contains real world examples with accounting. Homepage link

Port of the week: dnstop

Written by Solène, on 18 April 2018.
Tags: #unix

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Dnstop is an interactive console application to watch in realtime the DNS queries going through a network interface. It currently only supports UDP DNS requests, the man page says that TCP isn’t supported.

It has a lot of parameters and keybinding for the interactive use

To install it on OpenBSD: doas pkg_add dnstop

We will start dnstop on the wifi interface using a depth of 4 for the domain names: as root type dnstop -l 4 iwm0 and then press ‘3’ to display up to 3 sublevel, the -l 4 parameter means we want to know domains with a depth of 4, it means that if a request for the domain my.very.little.fqdn.com. happens, it will be truncated as very.little.fqdn.com. If you press ‘2’ in the interactive display, the earlier name will be counted in the line fqdn.com'.

Example of output:

Queries: 0 new, 6 total                           Tue Apr 17 07:17:25 2018
    
Query Name          Count      %   cum%
--------------- --------- ------ ------
perso.pw                3   50.0   50.0
foo.bar                 1   16.7   66.7
hello.mydns.com         1   16.7   83.3
mydns.com.lan           1   16.7  100.0

If you want to use it, read the man page first, it has a lot of parameters and can filters using specific expressions.

How to read a epub book in a terminal

Written by Solène, on 17 April 2018.
Tags: #unix

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If you ever had to read an ebook in a epub format, you may have find yourself stumbling on Calibre software. Personally, I don’t enjoy reading a book in Calibre at all. Choice is important and it seems that Calibre is the only choice for this task.

But, as the epub format is very simple, it’s possible to easily read it with any web browser even w3m or lynx.

With a few commands, you can easily find xhtml files that can be opened with a web browser, an epub file is a zip containing mostly xhtml, css and images files. The xhtml files have links to CSS and images contained in others folders unzipped.

In the following commands, I prefer to copy the file in a new directory because when you will unzip it, it will create folder in your current working directory.

$ mkdir /tmp/myebook/
$ cd /tmp/myebook
$ cp ~/book.epub .
$ unzip book.epub
$ cd OPS/xhtml
$ ls *xhtml

I tried with differents epub files, in most case you should find a lot of files named chapters-XX.xhtml with XX being 01, 02, 03 and so forth. Just open the files in the correct order with a web browser aka “html viewer”.

Port of the week: tig

Written by Solène, on 10 April 2018.
Tags: #unix #git #versioning

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Today we will discover the software named tig whose name stands for Text-mode Interface for Git.

To install it on OpenBSD: pkg_add tig

Tig is a light and easy to use terminal application to browse a git repository in an interactive manner. To use it, just ‘cd’ into a git repository on your filesystem and type tig. You will get the list of all the commits, with the author and the date. By pressing “Enter” key on a commit, you will get the diff. Tig also displays branching and merging in a graphical way.

Tig has some parameters, one I like a lot if blame which is used like this: tig blame afile. Tig will show the file content and will display for each line to date of last commit, it’s author and the small identifier of the commit. With this function, it gets really easy to find who modified a line or when it was modified.

Tig has a lot of others possibilities, you can discover them in its man pages.

Unofficial OpenBSD FAQ

Written by Solène, on 16 March 2018.
Tags: #openbsd70 #openbsd

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Frequently asked questions (with answers) on #openbsd IRC channel

Please read the official OpenBSD FAQ

I am writing this to answer questions asked too many times. If some answers get good enough, maybe we could try to merge it in the OpenBSD FAQ if the topic isn’t covered. If the topic is covered, then a link to the official FAQ should be used.

If you want to participate, you can fetch the page using gopher protocol and send me a diff:

$ printf '/~solene/article-openbsd-faq.txt\r\n' | nc dataswamp.org 70 > faq.md

OpenBSD features / not features

Here is a list for newcomers to tell what is and what is not OpenBSD

See OpenBSD Innovations

  • Packet Filter : super awesome firewall

  • Sane defaults : you install, it works, no tweak

  • Stability : upgrades go smooth and are easy

  • pledge and unveil : security features to reduce privileges of software, lots of ports are patched

  • W^X security

  • Microphone muted by default, unlockable by root only

  • Video devices owned by root by default, not usable by users until permission change

  • Has only FFS file system which is slow and has no “feature”

  • No wine for windows compatibility

  • No linux compatibility

  • No bluetooth support

  • No usb3 full speed performance

  • No VM guest additions

  • Only in-house VMM for being a VM host, only supports OpenBSD and some Linux

  • Poor fuse support (it crashes quite often)

  • No nvidia support (nvidia’s fault)

  • No container / docker / jails

Does OpenBSD has a Code Of Conduct?

No and there is no known plan of having one.

This is a topic upsetting OpenBSD people, just don’t ask about it and send patches.

What is the OpenBSD release process?

OpenBSD FAQ official information

The last two releases are called “-release” and are officially supported (patches for security issues are provided).

-stable version is the latest release with the base system patches applied, the -stable ports tree has some patches backported from -current, mainly to fix security issues. Official packages for -stable are built and are picked up automatically by pkg_add(1).

What is -current?

It’s the development version with latest packages and latest code. You shouldn’t use it only to get latest package versions.

How do I install -current ?

OpenBSD FAQ about current

  • download the latest snapshot install .iso or .fs file from your favorite mirror under /snapshots/ directory
  • boot from it

How do I upgrade to -current

OpenBSD FAQ about current

You can use the script sysupgrade -s, note that the flag is only useful if you are not running -current right now but harmless otherwise.

Monitor your systems with reed-alert

Written by Solène, on 17 January 2018.
Tags: #unix #lisp #reed-alert

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This article will present my software reed-alert, it checks user-defined states and send user-defined notification. I made it really easy to use but still configurable and extensible.

Description

reed-alert is not a monitoring tool producing graph or storing values. It does a job sysadmins are looking for because there are no alternative product (the alternatives comes from a very huge infrastructure like Zabbix so it’s not comparable).

From its configuration file, reed-alert will check various states and then, if it fails, will trigger a command to send a notification (totally user-defined).

Fetch it

This is a open-source and free software released under MIT license, you can install it with the following command:

# git clone git://bitreich.org/reed-alert
# cd reed-alert
# make
# doas make install

This will install a script reed-alert in /usr/local/bin/ with the default Makefile variables. It will try to use ecl and then sbcl if ecl is not installed.

A README file is available as documentation to describe how to use it, but we will see here how to get started quickly.

You will find a few files there, reed-alert is a Common LISP software and it has been chose for (I hope) good reasons that the configuration file is plain Common LISP.

There is a configuration file looking like a real world example named config.lisp.sample and another configuration file I use for testing named example.lisp containing lot of cases.

Let’s start

In order to use reed-alert we only need to create a new configuration file and then add a cron job.

Configuration

We are going to see how to configure reed-alert. You can find more explanations or details in the README file.

Alerts

We have to configure two kind of parameters, first we need to set-up a way to receive alerts, easiest way to do so is by sending a mail with “mail” command. Alerts are declared with the function alert and as parameters the alert name and the command to be executed. Some variables are replaced with values from the probe, in the README file you can find the list of probes, it looks like %date% or %params%.

In Common LISP functions are called by using a parenthesis before its name and until the parenthesis is closed, we are giving its parameters.

Example:

(alert mail "echo 'problem on %hostname%' | mail me@example.com")

One should take care about nesting quotes here.

reed-alert will fork a shell to start the command, so pipes and redirection works. You can be creative when writing alerts that:

  • use a SMS service
  • write a script to post on a forum
  • publishing a file on a server
  • send text to IRC with ii client

Checks

Now we have some alerts, we will configure some checks in order to make reed-alert useful. It uses probes which are pre-defined checks with parameters, a probe could be “has this file not been updated since N minutes ?” or “Is the disk space usage of partition X more than Y ?”

I chose to name the function “=>” to make a check, it isn’t a name and reminds an item or something going forward. Both previous example using our previous mail notifier would look like:

(=> mail file-updated :path "/program/file.generated" :limit "10")
(=> mail disk-usage   :limit 90)

It’s also possible to use shell commands and check the return code using the command probe, allowing the user to define useful checks.

(=> mail command :command "echo '/is-this-gopher-server-up?' | nc -w 3 dataswamp.org 70"
                 :desc "dataswamp.org gopher server")

We use echo + netcat to check if a connection to a socket works. The :desc keyword will give a nicer name in the output instead of just “COMMAND”.

Garniture

We wrote the minimum required to configure reed-alert, now the configuration file so your my-config.lisp file should looks like this:

(alert mail "echo 'problem on %hostname%' | mail me@example.com")
(=> mail file-updated :path "/program/file.generated" :limit "10")
(=> mail disk-usage   :limit 90)

Now, you can start it every 5 minutes from a crontab with this:

*/5 * * * * ( reed-alert /path/to/my-config.lisp )

If you prefer to use ecl:

*/5 * * * * ( reed-alert /path/to/my-config.lisp )

The time between each run is up to you, depending on what you monitor.

Important

By default, when a check returns a failure, reed-alert will only trigger the notifier associated once it reach the 3rd failure. And then, will notify again when the service is back (the variable %state% is replaced by start or end to know if it starts or stops.)

This is to prevent reed-alert to send a notification each time it checks, there is absolutely no need for this for most users.

The number of failures before triggering can be modified by using the keyword “:try” as in the following example:

(=> mail disk-usage :limit 90 :try 1)

In this case, you will get notified at the first failure of it.

The number of failures of failed checks is stored in files (1 per check) in the “states/” directory of reed-alert working directory.

New cl-yag version

Written by Solène, on 16 December 2017.
Tags: #unix #cl-yag

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Introduction

cl-yag is a static website generator. It's a software used to publish a website and/or a gopher hole from a list of articles. As the developer of cl-yag I'm happy to announce that a new version has been released.

New features

The new version, with its number 0.6, bring lot of new features :

  • supporting different markup language per article
  • date format configurable
  • gopher output format configurable
  • ship with the default theme "clyma", minimalist but responsive (the one used on this website)
  • easier to use
  • full user documentation

The code is available at git://bitreich.org/cl-yag, the program requires sbcl or ecl to work.

Per article markup language

The best feature I'm proud of is allowing to use a different language per article. While on my blog I choosed to use markdown, it's sometimes not adapted for more elaborated articles like the one about LISP containing code which was written in org-mode then converted to markdown manually to fit to cl-yag. Now, the user can declare a named "converter" which is a command line with pattern replacement, to produce the html file. We can imagine a lot of things with this, even producing a gallery with find + awk command. Now, I can use markdown by default and specify if I want to use org-mode or something else.

This is the way to declare a converter, taking org-mode as example, which is not very simple, because of emacs not being script friendly :

(converter :name :org-mode  :extension ".org"
	   :command (concatenate 'string
				 "emacs data/%IN --batch --eval '(with-temp-buffer (org-mode) "
				 "(insert-file \"%IN\") (org-html-export-as-html nil nil nil t)"
				 "(princ (buffer-string)))' --kill | tee %OUT"))

And an easy way to produce a gallery with awk from a .txt file containing a list of images path.

(converter :name :gallery :extension ".txt"
	   :command (concatenate 'string
				 "awk 'BEGIN { print \"<div class=\\\"gallery\\\">\"} "
				 "{ print \"<img src=\\\"static/images/\"$1\"\\\" />\" } "
				 " END { print  \"</div>\"} data/%IN | tee %OUT"))

The concatenate function is only used to improve the presentation, to split the command in multiples lines and make it easier to read. It's possible to write all the command in one line.

The patterns %IN and %OUT are replaced by the input file name and the output file name when the command is executed.

For an easier example, the default markdown converter looks like this, calling multimarkdown command :

(converter :name :markdown :extension ".md"
	   :command "multimarkdown -t html -o %OUT data/%IN")

It's really easy (I hope !) to add new converters you need with this feature.

Date format configurable

One problem I had with cl-yag is that it's plain vanilla Common LISP without libraries, so it's easier to fetch and use but it lacks some elaborated libraries like one to parse date and format a date. Before this release, I was writing in plain text "14 December 2017" in the date field of a blog post. It was easy to use, but not really usable in the RSS feed in the pubDate attribute, and if I wanted to change the display of the date for some reason, I would have to rewrite everything.

Now, the date is simply in the format "YYYYMMDD" like "20171231" for the 31rd December 2017. And in the configuration variable, there is a :date-format keyword to define the date display. This variable is a string allowing pattern replacement of the following variables :

%DayNumber
day of the month in number, from 1 to 31
%DayName
day of the week, from Monday to Sunday, names are written in english in the source code and can be translated
%MonthNumber
month in number, from 1 to 12
%MonthName
month name, from January to December, names are written in english in the source code and can be translated
%Year
year

Currently, as the time of writing, I use the value "%DayNumber %MonthName %Year"

A :gopher-format keyword exist in the configuration file to configure the date format in the gopher export. It can be different from the html one.

More Gopher configuration

There are cases where the gopher server use an unusual syntax compared to most of the servers. I wanted to make it configurable, so the user could easily use cl-yag without having to mess with the code. I provide the default for geomyidae and in comments another syntax is available. There is also a configurable value to indicates where to store the gopher page menu, it's not always gophermap, it could be index.gph or whatever you need.

Easier to use

A comparison of code will make it easier to understand. There was a little change the way blog posts are declared :

From

(defparameter *articles*
  (list
   (list :id "third-article"  :title "My third article" :tag "me" :date "20171205")
   (list :id "second-article" :title "Another article"  :tag "me" :date "20171204")
   (list :id "first-article"  :title "My first article" :tag "me" :date "20171201")
   ))

to

(post :id "third-article"  :title "My third article" :tag "me" :date "20171205")
(post :id "second-article" :title "Another article"  :tag "me" :date "20171204")
(post :id "first-article"  :title "My first article" :tag "me" :date "20171201")

Each post are independtly declared and I plan to add a "page" function to create static pages, but this is going to be for the next version !

Future work

I am very happy to hack on cl-yag, I want to continue improving it but I should really think about each feature I want to add. I want to keep it really simple even if it limits the features.

I want to allow the creation of static pages like "About me", "Legal" or "websites I liked" that integrates well in the template. The user may not want all the static pages links to go at the same place in the template, or use the same template. I'm thinking about this.

Also, I think the gopher generation could be improved, but I still have no idea how.

Others themes may come in the default configuration, allowing the user to have a choice between themes. But as for now, I don't plan to bring a theme using javascript.

How to merge changes with git when you are a noob

Written by Solène, on 13 December 2017.
Tags: #git #versioning

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I’m very noob with git and I always screw everything when someone clone one of my repo, contributes and asks me to merge the changes.

Now I found an easy way to merge commits from another repository. Here is a simple way to handle this. We will get changes from project1_modified to merge it into our project1 repository. This is not the fastest way or maybe not the optimal way, but I found it to work reliabily.

$ cd /path/to/projects
$ git clone git://remote/project1_modified
$ cd my_project1
$ git checkout master
$ git remote add modified ../project1_modified/
$ git remote update
$ git checkout -b new_code
$ git merge modified/master
$ git checkout master
$ git merge new_code
$ git branch -d new_code

This process will makes you download the repository of the people who contributed to the code, then you add it as a remote sources into your project, you create a new branch where you will do the merge, if something is wrong you will be able to manage conflicts easily. Once you tried the code and you are fine, you need to merge this branch to master and then, when you are done, you can delete the branch.

If later you need to get new commits from the other repo, it become easier.

$ cd /path/to/projects
$ cd project1_modified
$ git pull
$ cd ../my_project1
$ git pull modified
$ git merge modified/master

And you are done !

How to type using only one hand: keyboard mirroring

Written by Solène, on 12 December 2017.
Tags: #unix

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Hello

Today is a bit special because I’m writing with a mirror keyboard layout. I use only half my keyboard to type all characters. To make things harder, the layout is qwerty while I use azerty usually (I’m used to qwerty but it doesn’t help).

Here, “caps lock” is a modifier key that must be pressed to obtain characters of the other side. As a mirror, one will find ‘p’ instead of ‘q’ or ‘h’ instead of ‘g’ while pressing caps lock.

It’s even possible to type backspace to delete characters or to achieve a newline. All the punctuation isn’t available throught this, only ‘.<|¦>’",'.

While I type this I get a bit faster and it become more and more easier. It’s definitely worth if you can’t use hands two.

This a been made possible by Randall Munroe. To enable it just download the file Here and type

xkbcomp mirrorlayout.kbd $DISPLAY

backspace is use with tilde and return with space, using the modifier of course.

I’ve spent approximately 15 minutes writing this, but the time spent hasn’t been linear, it’s much more fluent now !

[Mirrorboard: A one-handed keyboard layout for the lazy by Randall Munroe] (https://blog.xkcd.com/2007/08/14/mirrorboard-a-one-handed-keyboard-layout-for-the-lazy/)

Showing some Common Lisp features

Written by Solène, on 05 December 2017.
Tags: #lisp

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Introduction: comparing LISP to Perl and Python

We will refer to Common LISP as CL in the following article.

I wrote it to share what I like about CL. I’m using Perl to compare CL features. I am using real world cases for the average programmer. If you are a CL or perl expert, you may say that some example could be rewritten with very specific syntax to make it smaller or faster, but the point here is to show usual and readable examples for usual programmers.

This article is aimed at people with programming interest, some basis of programming knowledge are needed to understand the following. If you know how to read C, Php, Python or Perl it should be enough. Examples have been choosed to be easy.

I thank my friend killruana for his contribution as he wrote the python code.

Variables

Scope: global

Common Lisp code

(defparameter *variable* "value")

Defining a variable with defparameter on top-level (= outside of a function) will make it global. It is common to surround the name of global variables with * character in CL code. This is only for readability for the programmer, the use of * has no incidence.

Perl code

my $variable = "value";

Python code

variable = "value";

Scope: local

This is where it begins interesting in CL. Declaring a local variable with let create a new scope with parenthesis where the variable isn’t known outside of it. This prevent doing bad things with variables not set or already freed. let can define multiple variables at once, or even variables depending on previously declared variables using let*

Common Lisp code

(let ((value (http-request)))
  (when value
    (let* ((page-title (get-title value))
           (title-size (length page-title)))
      (when page-title
        (let ((first-char (subseq page-title 0 1)))
          (format t "First char of page title is ~a~%" first-char))))))

Perl code

{
    local $value = http_request;
    if($value) {
        local $page_title = get_title $value;
        local $title_size = get_size $page_title;
        if($page_title) {
            local $first_char = substr $page_title, 0, 1;
            printf "First char of page title is %s\n", $first_char;
        }
    }
}

The scope of a local value is limited to the parent curly brakets, of a if/while/for/foreach or plain brakets.

Python code

if True:
    hello = 'World'
print(hello) # displays World

There is no way to define a local variable in python, the scope of the variable is limited to the parent function.

Printing and format text

CL has a VERY powerful function to print and format text, it’s even named format. It can even manage plurals of words (in english only) !

Common Lisp code

(let ((words (list "hello" "Dave" "How are you" "today ?")))
  (format t "~{~a ~}~%" words))

format can loop over lists using ~{ as start and ~} as end.

Perl code

my @words = @{["hello", "Dave", "How are you", "today ?"]};
foreach my $element (@words) {
    printf "%s ", $element;
}
print "\n";

Python code

# Printing and format text
# Loop version
words = ["hello", "Dave", "How are you", "today ?"]
for word in words:
    print(word, end=' ')
print()
    
# list expansion version
words = ["hello", "Dave", "How are you", "today ?"]
print(*words)

Functions

function parameters: rest

Sometimes we need to pass to a function a not known number of arguments. CL supports it with &rest keyword in the function declaration, while perl supports it using the @_ sigil.

Common Lisp code

(defun my-function(parameter1 parameter2 &rest rest)
  (format t "My first and second parameters are ~a and ~a.~%Others parameters are~%~{    - ~a~%~}~%"
          parameter1 parameter2 rest))
    
(my-function "hello" "world" 1 2 3)

Perl code

sub my_function {
    my $parameter1 = shift;
    my $parameter2 = shift;
    my @rest = @_;
    
    printf "My first and second parameters are %s and %s.\nOthers parameters are\n",
        $parameter1, $parameter2;
    
    foreach my $element (@rest) {
        printf "    - %s\n", $element;
    }
}
    
my_function "hello", "world", 0, 1, 2, 3;

Python code

def my_function(parameter1, parameter2, *rest):
    print("My first and second parameters are {} and {}".format(parameter1, parameter2))
    print("Others parameters are")
    for parameter in rest:
        print(" - {}".format(parameter))
    
my_function("hello", "world", 0, 1, 2, 3)

The trick in python to handle rests arguments is the wildcard character in the function definition.

function parameters: named parameters

CL supports named parameters using a keyword to specify its name. While it’s not at all possible on perl. Using a hash has parameter can do the job in perl.

CL allow to choose a default value if a parameter isn’t set, it’s harder to do it in perl, we must check if the key is already set in the hash and give it a value in the function.

Common Lisp code

(defun my-function(&key (key1 "default") (key2 0))
  (format t "Key1 is ~a and key2 (~a) has a default of 0.~%"
          key1 key2))
    
(my-function :key1 "nice" :key2 ".Y.")

There is no way to pass named parameter to a perl function. The best way it to pass a hash variable, check the keys needed and assign a default value if they are undefined.

Perl code

sub my_function {
    my $hash = shift;
    
    if(! exists $hash->{key1}) {
        $hash->{key1} = "default";
    }
    
    if(! exists $hash->{key2}) {
        $hash->{key2} = 0;
    }
    
    printf "My key1 is %s and key2 (%s) default to 0.\n",
        $hash->{key1}, $hash->{key2};
}
    
my_function { key1 => "nice", key2 => ".Y." };

Python code

def my_function(key1="default", key2=0):
    print("My key1 is {} and key2 ({}) default to 0.".format(key1, key2))
    
my_function(key1="nice", key2=".Y.")

Loop

CL has only one loop operator, named loop, which could be seen as an entire language itself. Perl has do while, while, for and foreach.

loop: for

Common Lisp code

(loop for i from 1 to 100
   do
     (format t "Hello ~a~%" i))

Perl code

for(my $i=1; $i <= 100; $i++) {
    printf "Hello %i\n";
}

Python code

for i in range(1, 101):
   print("Hello {}".format(i))

loop: foreach

Common Lisp code

(let ((elements '(a b c d e f)))
  (loop for element in elements
     counting element into count
     do
       (format t "Element number ~s : ~s~%"
               count element)))

Perl code

# verbose and readable version
my @elements = @{['a', 'b', 'c', 'd', 'e', 'f']};
my $count = 0;
foreach my $element (@elements) {
    $count++;
    printf "Element number %i : %s\n", $count, $element;
}
    
# compact version
for(my $i=0; $i<$#elements+1;$i++) {
    printf "Element number %i : %s\n", $i+1, $elements[$i];
}

Python code

# Loop foreach
elements = ['a', 'b', 'c', 'd', 'e', 'f']
count = 0
for element in elements:
    count += 1
    print("Element number {} : {}".format(count, element))
    
# Pythonic version
elements = ['a', 'b', 'c', 'd', 'e', 'f']
for index, element in enumerate(elements):
    print("Element number {} : {}".format(index, element))

LISP only tricks

Store/restore data on disk

The simplest way to store data in LISP is to write a data structure into a file, using print function. The code output with print can be evaluated later with read.

Common Lisp code

(defun restore-data(file)
  (when (probe-file file)
    (with-open-file (x file :direction :input)
      (read x))))
    
(defun save-data(file data)
  (with-open-file (x file
                     :direction :output
                     :if-does-not-exist :create
                     :if-exists :supersede)
    (print data x)))
    
;; using the functions
(save-data "books.lisp" *books*)
(defparameter *books* (restore-data "books.lisp"))

This permit to skip the use of a data storage format like XML or JSON. Common LISP can read Common LISP, this is all it needs. It can store objets like arrays, lists or structures using plain text format. It can’t dump hash tables directly.

Creating a new syntax with a simple macro

Sometimes we have cases where we need to repeat code and there is no way to reduce it because it’s too much specific or because it’s due to the language itself. Here is an example where we can use a simple macro to reduce the written code in a succession of conditions doing the same check.

We will start from this

Common Lisp code

(when value
  (when (string= line-type "3")
    (progn
      (print-with-color "error" 'red line-number)
      (log-to-file "error")))
  (when (string= line-type "4")
    (print-with-color text))
  (when (string= line-type "5")
    (print-with-color "nothing")))

to this, using a macro

Common Lisp code

(defmacro check(identifier &body code)
  `(progn
     (when (string= line-type ,identifier)
     ,@code)))
    
(when value
  (check "3"
         (print-with-color "error" 'red line-number)
         (log-to-file "error"))
  (check "4"
         (print-with-color text))
  (check "5"
         (print-with-color "nothing")))

The code is much more readable and the macro is easy to understand. One could argue that in another language a switch/case could work here, I choosed a simple example to illustrate the use of a macro, but they can achieve more.

Create powerful wrappers with macros

I’m using macros when I need to repeat code that affect variables. A lot of CL modules offers a structure like with-something, it’s a wrapper macro that will do some logic like opening a database, checking it’s opened, closing it at the end and executing your code inside.

Here I will write a tiny http request wrapper, allowing me to write http request very easily, my code being able to use variables from the macro.

Common Lisp code

(defmacro with-http(url)
  `(progn
     (multiple-value-bind (content status head)
         (drakma:http-request ,url :connection-timeout 3)
       (when content
         ,@code))))
    
(with-http "https://dataswamp.org/"
  (format t "We fetched headers ~a with status ~a. Content size is ~d bytes.~%"
          status head (length content)))

In Perl, the following would be written like this

Perl code

sub get_http {
    my $url = $1;
    my %http = magic_http_get $url;
    if($http{content}) {
        return %http;
    } else {
        return undef;
    }
}
    
{
    local %data = get_http "https://dataswamp.org/";
    if(%data) {
        printf "We fetched headers %s with status %d. Content size is %d bytes.\n",
            $http{headers}, $http{status}, length($http{content});
    }
}

The curly brackets are important there, I want to emphase that the local %data variable is only available inside the curly brackets. Lisp is written in a successive of local scope and this is something I really like.

Python code

import requests
with requests.get("https://dataswamp.org/") as fd:
    print("We fetched headers %s with status %d. Content size is %s bytes." \
                % (list(fd.headers.keys()), fd.status_code, len(fd.content)))

Allow wide resolution on intel graphics laptop

Written by Solène, on 22 November 2017.
Tags: #hardware

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I just received a wide screen with a 2560x1080 resolution but xrandr wasn’t allowing me to use it. The intel graphics specifications say that I should be able to go up to 4096xsomething so it’s a software problem.

Generate the informations you need with the gtf command:

$ gtf 2560 1080 59.9

Keep the numbers after the resolution name between quotes, so in Modeline "2560x1080_59.90" 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync keep only 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync

Now add the new resolution and make it available to your output (mine is HDMI2):

$ xrandr --newmode "2560x1080" 230.37 2560 2728 3000 3440 1080 1081 1084 1118 -HSync +Vsync
$ xrandr --addmode HDMI2 2560x1080

You can now use this mode with arandr using the GUI or with xrandr by typing xrandr --output HDMI1 --mode 2560x1080

You will need to set the new mode each time the system start. I added the 2 lines in my ~/.xsession file which starts stumpwm.

Low bandwidth: Fetch OpenBSD sources

Written by Solène, on 09 November 2017.
Tags: #openbsd70 #openbsd #versioning

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When you fetch OpenBSD src or ports from CVS and that you want to save bandwidth during the process there is a little trick that change everything: compression

Just add -z9 to the parameter of your cvs command line and the remote server will send you compressed files, saving 10 times the bandwidth, or speeding up 10 times the transfer, or both (I’m in the case where I have differents users on my network and I’m limiting my incoming bandwidth so other people can have bandwidth too so it is important to reduce the packets transffered if possible).

The command line should looks like:

$ cvs -z9 -qd anoncvs@anoncvs.fr.openbsd.org:/cvs checkout -P src

Don’t abuse this, this consumes CPU on the mirror.

Gentoo port of the week: slrn

Written by Solène, on 08 November 2017.
Tags: #gentoo #portoftheweek

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Introduction

Hello,

Today I will speak about slrn, a nntp client. I’m using it to fetch mailing lists I’m following (without necesserarly subscribing to them) and read it offline. I’ll speak about using nntp to read news-groups, I’m not sure but in a more general way nntp is used to access usenet. I’m not sure to know what usenet is, so we will stick here by connecting to mailing-list archives offered by gmane.org (which offers access to mailing-lists and newsgroups through nntp).

Long story short, recently I moved and now I have a very poor DSL connection. Plus I’m often moving by train with nearly no 4G/LTE support during the trip. I’m going to write about getting things done offline and about reducing bandwith usage. This is a really interesting topic in our hyper-connected world.

So, back to slrn, I want to be able to fetch lot of news and read it later. Every nntp client I tried were getting the articles list (in nntp, an article = a mail, a forum = mailing list) and then it download each article when we want to read it. Some can cache the result when you fetch an article, so if you want to read it later it is already fetched. While slrn doesn’t support caching at all, it comes with the utility slrnpull which will create a local copy of forums you want, and slrn can be configured to fetch data from there. slrnpull need to be configured to tell it what to fetch, what to keep etc… and a cron will start it sometimes to fetch the new articles.

Configuration

The following configuration is made to be simple to use, it runs with your regular user. This is for gentoo, maybe some another system would provide a dedicated user and everything pre-configured.

Create the folder for slrnpull and change the owner:

$ sudo mkdir /var/spool/slrnpull
$ sudo chown user /var/spool/slrnpull

slrnpull configuration file must be placed in the folder it will use. So edit /var/spool/slrnpull/slrnpull.conf as you want, my configuration file is following.

default 200 45 0
# indicates a default value of 20 articles to be retrieved from the server and
# that such an article will expire after 14 days.
    
gmane.network.gopher.general
gmane.os.freebsd.questions
gmane.os.freebsd.devel.ports
gmane.os.openbsd.misc
gmane.os.openbsd.ports
gmane.os.openbsd.bugs

The client slrn needs to be configured to find the informations from slrnpull.

File ~/.slrnrc:

set hostname "your.hostname.domain"
set spool_inn_root "/var/spool/slrnpull"
set spool_root "/var/spool/slrnpull/news"
set spool_nov_root "/var/spool/slrnpull/news"
set read_active 1
set use_slrnpull 1
set post_object "slrnpull"
set server_object "spool"

Add this to your crontab to fetch news once per hour (at HH:00 minutes):

0 * * * * NNTPSERVER=news.gmane.org slrnpull -d /var/spool/slrnpull/

Now, just type slrn and enjoy.

Cheat Sheet

Quick cheat sheet for using slrn, there is a help using “?” but it is not very easy to understand at first.

  • h : hide/display the article view
  • space : scroll to next page in the article, go to next at the end
  • enter : scroll one line
  • tab : scroll to the end of quotes
  • c : mark all as read

Tips

  • when a forum is empty, it is not shown by default

I found that a slrnconf software provide a GUI to configure slrn exists, I didn’t try it.

Going further

It seems nntp clients supports a score file that can mark interesting articles using user defined rules.

nntp protocol allow to submit articles (reply or new thread) but I have no idea how it works. Someone told me to forget about this and use mails to mailing-lists when it is possible.

leafnode daemon can be used instead of slrnpull in a more generic way. It is a nntp server that one would use locally as a proxy to nntp servers. It will mirror forums you want and serve it back through nntp, allowing you to use any nntp client (slrnpull enforces the use of slrn). leafnode seems old, a v2 is still in development but seems rather inactive. Leafnode is old and complicated, I wanted something KISS (Keep It Simple Stupid) and it is not.

Others clients you may want to try

nntp console client

  • gnus (in emacs)
  • wanderlust (in emacs too)
  • alpine

GUI client

  • pan (may be able to download, but I failed using it)
  • seamonkey (the whole mozilla suite supports nntp)

Zooming with emacs, tmux or stumpwm

Written by Solène, on 25 October 2017.
Tags: #emacs #window-manager #tmux

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Hey ! You use stumpwm, emacs or tmux and your screen (not the GNU screen) split in lot of parts ? There is a solution to improve that. ZOOMING !

Each of them work with a screen divided into panes/windows (the meaning of theses words change between the program), sometime you want want to have the one where your work in fullscreen. An option exists in each of them to get fullscreen temporarly on a window.

Emacs: (not native)

This is not native in emacs, you will need to install zoom-window from your favorite repository.

Add the thoses lines in your ~/.emacs:

(require 'zoom-window)
(global-set-key (kbd "C-x C-z") 'zoom-window-zoom)

Type C-x C-z to zoom/unzoom your current frame

Tmux

Toogle zoom (in or out)

C-b z

Stumpwm

Add this to your ~/.stumpwmrc

(define-key *root-map* (kbd "z")            "fullscreen")

Using “prefix z” the current window will toggle fullscreen.

Gentoo port of the week: Nethogs

Written by Solène, on 17 October 2017.
Tags: #portoftheweek #gentoo

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Today I will present you a nice port (from Gentoo this time, not from a FreeBSD) and this port is even linux only.

nethogs is a console program which shows the bandwidth usage of each running application consuming network. This can be particulary helpful to find which application is sending traffic and at which rate.

It can be installed with emerge as simple as emerge -av net-analyzer/nethogs.

It is very simple of use, just type nethogs in a terminal (as root). There are some parameters and it’s a bit interactive but I recommend reading the manual if you need some details about them.

I am currently running Gentoo on my main workstation, that makes me discover new things so maybe I will write more regularly about gentoo ports.

Using firefox on Guix distribution

Written by Solène, on 16 August 2017.
Tags: #linux #guix

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Update 2020: This method may certainly not work anymore but I don’t have a Guix installation to try.

I’m new to Guix, it’s a wonderful system but it’s such different than any other usual linux distribution that it’s hard to achieve some basics tasks. As Guix is 100% free/libre software, Firefox has been removed and replaced by icecat. This is nearly the same software but some “features” has been removed (like webRTC) for some reasons (security, freedom). I don’t blame Guix team for that, I understand the choice.

But my problem is that I need Firefox. I finally achieve to get it working from the official binary downloaded from mozilla website.

You need to install some packages to get the libraries, which will become available under your profile directory. Then, tells firefox to load libraries from there and it will start.

guix package -i glibc glib gcc gtk+ libxcomposite dbus-glib libxt
LD_LIBRARY_PATH=~/.guix-profile/lib/ ~/.guix-profile/lib/ld-linux-x86-64.so.2 ~/firefox_directory/firefox

Also, it seems that running icecat and firefox simultanously works, they store data in ~/.mozilla/icecat and ~/.mozilla/firefox so they are separated.

Using emacs to manage mails with mu4e

Written by Solène, on 15 June 2017.
Tags: #emacs #email

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In this article we will see how to fetch, read and manage your emails from Emacs using mu4e. The process is the following: mbsync command (while mbsync is the command name, the software name is isync) create a mirror of an imap account into a Maildir format on your filesystem. mu from mu4e will create a database from the Maildir directory using xapian library (full text search database), then mu4e (mu for emacs) is the GUI which queries xapian database to manipulates your mails.

Mu4e handles with dynamic bookmarks, so you can have some predefined filters instead of having classic folders. You can also do a query and reduce the results with successives queries.

You may have heard about using notmuch with emacs to manage mails, mu4e and notmuch doesn’t do the same job. While notmuch is a nice tool to find messages from queries and create filters, it operates as a read-only tool and can’t do anything with your mail. mu4e let you write mail, move, delete, flag etc… AND still allow to make complex queries.

I wrote this article to allow people to try mu4e quickly, you may want to read both isync and mu4e manual to have a better configuration suiting your needs.

Installation

On OpenBSD you need to install 2 packages:

# pkg_add mu4 isync

isync configuration

We need to configure isync to connect to the IMAP server:

Edit the file ~/.mbsyncrc, there is a trick to not have the password in clear text in the configuration file, see isync configuration manual for this:

iMAPAccount my_imap
Host my_host_domain.info
User imap_user
Pass my_pass_in_clear_text
SSLType IMAPS
    
IMAPStore my_imap-remote
Account my_imap
    
MailDirStore my_imap-local
Path ~/Maildir/my_imap/
Inbox ~/Maildir/my_imap/Inbox
SubFolders Legacy
    
channel my_imap
Master :my_imap-remote:
Slave :my_imap-local:
Patterns *
Create Slave
Expunge Both

mu4e / emacs configuration

We need to configure mu4e in order to tell where to find the mail folder. Add this to your ~/.emacs file.

(require 'mu4e)
(setq mu4e-maildir "~/Maildir/my_imap/"
      mu4e-sent-folder "/Sent Messages/"
      mu4e-trash-folder "/Trash"
      mu4e-drafts-folder "/Drafts")

First start

A few commands are needed in order to make everything works. We need to create the base folder as mbsync command won’t do the job for some reason, and we need mu to index the mails the first time.

mbsync can takes a moment because it will download ALL your mails.

$ mkdir -p ~/Maildir/my_imap
$ mbsync -aC
$ mu init --maildir=~/Maildir/my_imap
$ mu index

How to use mu4e

start emacs, run M-x mu4e RET and enjoy, the documentation of mu4e is well done. Press “U” at mu4e screen to synchronize with imap server.

A query for mu4e looks like this:

list:misc.openbsd.org flag:unread avahi

This query will search mails having list header “misc.openbsd.org” and which are unread and which contains “avahi” pattern.

date:20140101..20150215 urgent

This one will looks for mails within date range of 1st january 2014 to 15th february 2015 containing word “urgent”.

Additional notes

The current setup doesn’t handle sending mails, I’ll write another article about this. This requires configuring a smtp authentification and an identify for mu4e.

Also, you may need to tweak mbsync configuration or mu4e configuration, some settings must be changed depending on the imap server, this is particuliarly important for deleted mails.

How to change Firefox locale to ... esperanto?

Written by Solène, on 14 May 2017.
Tags: #firefox

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Hello !

Today I felt the need to change the language of my Firefox browser to esperanto but I haven’t been able to do this, it is not straightforward…

First, you need to install your language pack, depending if you use the official Mozilla Firefox or Icecat, the rebranded firefox with non-free stuff removed

Then, open about:config in firefox, we will need to change 2 keys. Firefox needs to know that we don’t want to use our user’s locale as Firefox language and which language we want to set.

  • set intl.locale.matchOS to false
  • set general.useragent.locale to the language code you want (eo for esperanto)
  • restart firefox/icecat

you’re done ! Bonan tagon

Markup languages comparison

Written by Solène, on 13 April 2017.
Tags: #unix

Comments on Fediverse/Mastodon

For the fun, here is a few examples of the same output in differents markup languages. The list isn’t exhaustive of course.

This is org-mode:

* This is a title level 1
    
+ first item
+ second item
+ third item with a [[http://dataswamp.org][link]]
    
** title level 2
    
Blah blah blah blah blah
blah blah blah *bold* here

#+BEGIN_SRC lisp
(let ((hello (init-string)))
   (format t "~A~%" (+ 1 hello))
   (print hello))
#+END_SRC

This is markdown :

# this is title level 1
    
+ first item
+ second item
+ third item with a [Link](http://dataswamp.org)
    
## Title level 2
    
Blah blah blah blah blah
blah blah blah **bold** here
    
    (let ((hello (init-string)))
       (format t "~A~%" (+ 1 hello))
       (print hello))
    
or
    
```
(let ((hello (init-string)))
   (format t "~A~%" (+ 1 hello))
   (print hello))
```

This is HTML :

<h1>This is title level 1</h1>
<ul>
  <li>first item></li>
  <li>second item</li>
  <li>third item with a <a href="http://dataswamp.org">link</a></li>
</ul>
    
<h2>Title level 2</h2>
    
<p>Blah blah blah blah blah
  blah blah blah <strong>bold</strong> here
    
<code><pre>(let ((hello (init-string)))
   (format t "~A~%" (+ 1 hello))
   (print hello))</pre></code>

This is LaTeX :

\begin{document}
    
\section{This is title level 1}
    
\begin{itemize}
\item First item
\item Second item
\item Third item
\end{itemize}
    
\subsection{Title level 2}
    
Blah blah blah blah blah
blah blah blah \textbf{bold} here
    
\begin{verbatim}
(let ((hello (init-string)))
    (format t "~A~%" (+ 1 hello))
    (print hello))
\end{verbatim}
    
\end{document}

OpenBSD 6.1 released

Written by Solène, on 11 April 2017.
Tags: #openbsd #unix

Comments on Fediverse/Mastodon

Today OpenBSD 6.1 has been released, I won’t copy & paste the change list but, in a few words, it gets better.

Link to the official announce

I already upgraded a few servers, with both methods. One with bsd.rd upgrade but that requires physical access to the server and the other method well explained in the upgrade guide which requires to untar the files and do move some files. I recommend using bsd.rd if possible.

Connect to pfsense box console by usb

Written by Solène, on 10 April 2017.
Tags: #unix #networking #openbsd70 #openbsd

Comments on Fediverse/Mastodon

Hello,

I have a pfsense appliance (Netgate 2440) with a usb console port, while it used to be a serial port, now devices seems to have a usb one. If you plug an usb wire from an openbsd box to it, you woull see this in your dmesg

uslcom0 at uhub0 port 5 configuration 1 interface 0 "Silicon Labs CP2104 USB to UART Bridge Controller" rev 2.00/1.00 addr 7
ucom0 at uslcom0 portno 0

To connect to it from OpenBSD, use the following command:

# cu -l /dev/cuaU0 -s 115200

And you’re done

List of useful tools

Written by Solène, on 22 March 2017.
Tags: #unix

Comments on Fediverse/Mastodon

Here is a list of software that I find useful, I will update this list everytime I find a new tool. This is not an exhaustive list, theses are only software I enjoy using:

Backup Tool

  • duplicity
  • borg
  • restore/dump

File synchronization tool

  • unison
  • rsync
  • lsyncd

File sharing tool / “Cloud”

  • boar
  • nextcloud / owncloud
  • seafile
  • pydio
  • syncthing (works as peer-to-peer without a master)
  • sparkleshare (uses a git repository so I would recommend storing only text files)

Editors

  • emacs
  • vim
  • jed

Web browsers using keyboard

  • qutebrowser
  • firefox with vimperator extension

Todo list / Personal Agenda…

  • org-mode (within emacs)
  • ledger (accounting)

Mail client

  • mu4e (inside emacs, requires the use of offlineimap or mbsync to fetch mails)

Network

  • curl
  • bwm-ng (to see bandwith usage in real time)
  • mtr (traceroute with a gui that updates every n seconds)

Files integrity

  • bitrot
  • par2cmdline
  • aide

Image viewer

  • sxiv
  • feh

Stuff

  • entr (run command when a file change)
  • rdesktop (RDP client to connect to Windows VM)
  • xclip (read/set your X clipboard from a script)
  • autossh (to create tunnels that stays up)
  • mosh (connects to your ssh server with local input and better resilience)
  • ncdu (watch file system usage interactively in cmdline)
  • mupdf (PDF viewer)
  • pdftk (PDF manipulation tool)
  • x2x (share your mouse/keyboard between multiple computers through ssh)
  • profanity (XMPP cmdline client)
  • prosody (XMPP server)
  • pgmodeler (PostgreSQL database visualization tool)

How to check your data integrity?

Written by Solène, on 17 March 2017.
Tags: #unix #security

Comments on Fediverse/Mastodon

Today, the topic is data degradation, bit rot, birotting, damaged files or whatever you call it. It’s when your data get corrupted over the time, due to disk fault or some unknown reason.

What is data degradation ?

I shamelessy paste one line from wikipedia: “Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. The phenomenon is also known as data decay or data rot.”.

Data degradation on Wikipedia

So, how do we know we encounter a bit rot ?

bit rot = (checksum changed) && NOT (modification time changed)

While updating a file could be mistaken as bit rot, there is a difference

update = (checksum changed) && (modification time changed)

How to check if we encounter bitrot ?

There is no way you can prevent bitrot. But there are some ways to detect it, so you can restore a corrupted file from a backup, or repair it with the right tool (you can’t repair a file with a hammer, except if it’s some kind of HammerFS ! :D )

In the following I will describe software I found to check (or even repair) bitrot. If you know others tools which are not in this list, I would be happy to hear about it, please mail me.

In the following examples, I will use this method to generate bitrot on a file:

% touch -d "2017-03-16T21:04:00" my_data/some_file_that_will_be_corrupted
% generate_checksum_database_with_tool
% echo "a" >> my_data/some_file_that_will_be_corrupted
% touch -d "2017-03-16T21:04:00" my_data/some_file_that_will_be_corrupted
% start_tool_for_checking

We generate the checksum database, then we alter a file by adding a “a” at the end of the file and we restore the modification and acess time of the file. Then, we start the tool to check for data corruption.

The first touch is only for convenience, we could get the modification time with stat command and pass the same value to touch after modification of the file.

bitrot

This is a python script, it’s very easy to use. I will scan a directory and create a database with the checksum of the files and their modification date.

Initialization usage:

% cd /home/my_data/
% bitrot
Finished. 199.41 MiB of data read. 0 errors found.
189 entries in the database, 189 new, 0 updated, 0 renamed, 0 missing.
Updating bitrot.sha512... done.
% echo $?
0

Verify usage (case OK):

% cd /home/my_data/
% bitrot
Checking bitrot.db integrity... ok.
Finished. 199.41 MiB of data read. 0 errors found.
189 entries in the database, 0 new, 0 updated, 0 renamed, 0 missing.
% echo $?
0

Exit status is 0, so our data are not damaged.

Verify usage (case Error):

% cd /home/my_data/
% bitrot
Checking bitrot.db integrity... ok.
error: SHA1 mismatch for ./sometextfile.txt: expected 17b4d7bf382057dc3344ea230a595064b579396f, got db4a8d7e27bb9ad02982c0686cab327b146ba80d. Last good hash checked on 2017-03-16 21:04:39.
Finished. 199.41 MiB of data read. 1 errors found.
189 entries in the database, 0 new, 0 updated, 0 renamed, 0 missing.
error: There were 1 errors found.
% echo $?
1

When something is wrong. As the exit status of bitrot isn’t 0 when it fails, it’s easy to write a script running every day/week/month.

Github page

bitrot is available in OpenBSD ports in sysutils/bitrot since 6.1 release.

par2cmdline

This tool works with PAR2 archives (see below for more informations about what PAR ) and from them, it will be able to check your data integrity AND repair it.

While it has some pros like being able to repair data, the cons is that it’s not very easy to use. I would use this one for checking integrity of long term archives that won’t changes. The main drawback comes from PAR specifications, the archives are created from a filelist, if you have a directory with your files and you add new files, you will need to recompute ALL the PAR archives because the filelist changed, or create new PAR archives only for the new files, but that will make the verify process more complicated. That doesn’t seems suitable to create new archives for every bunchs of files added in the directory.

PAR2 let you choose the percent of a file you will be able to repair, by default it will create the archives to be able to repair up to 5% of each file. That means you don’t need a whole backup for the files (while it’s would be a bad idea) and only an approximately extra of 5% of your data to store.

Create usage:

% cd /home/
% par2 create -a integrity_archive -R my_data
Skipping 0 byte file: /home/my_data/empty_file
    
Block size: 3812
Source file count: 17
Source block count: 2000
Redundancy: 5%
Recovery block count: 100
Recovery file count: 7
    
Opening: my_data/[....]
[text cut here]
Opening: my_data/[....]

Computing Reed Solomon matrix.
Constructing: done.
Wrote 381200 bytes to disk
Writing recovery packets
Writing verification packets
Done

% echo $?
0
    
% ls -1
integrity_archive.par2
integrity_archive.vol000+01.par2
integrity_archive.vol001+02.par2
integrity_archive.vol003+04.par2
integrity_archive.vol007+08.par2
integrity_archive.vol015+16.par2
integrity_archive.vol031+32.par2
integrity_archive.vol063+37.par2
my_data

Verify usage (OK):

% par2 verify integrity_archive.par2 
Loading "integrity_archive.par2".
Loaded 36 new packets
Loading "integrity_archive.vol000+01.par2".
Loaded 1 new packets including 1 recovery blocks
Loading "integrity_archive.vol001+02.par2".
Loaded 2 new packets including 2 recovery blocks
Loading "integrity_archive.vol003+04.par2".
Loaded 4 new packets including 4 recovery blocks
Loading "integrity_archive.vol007+08.par2".
Loaded 8 new packets including 8 recovery blocks
Loading "integrity_archive.vol015+16.par2".
Loaded 16 new packets including 16 recovery blocks
Loading "integrity_archive.vol031+32.par2".
Loaded 32 new packets including 32 recovery blocks
Loading "integrity_archive.vol063+37.par2".
Loaded 37 new packets including 37 recovery blocks
Loading "integrity_archive.par2".
No new packets found
    
There are 17 recoverable files and 0 other files.
The block size used was 3812 bytes.
There are a total of 2000 data blocks.
The total size of the data files is 7595275 bytes.
    
Verifying source files:
    
Target: "my_data/....." - found.
[...cut here...]
Target: "my_data/....." - found.
    
    
All files are correct, repair is not required.
% echo $?
0

Verify usage (with error):

par2 verify integrity_archive.par.par2                                                 
Loading "integrity_archive.par.par2".
Loaded 36 new packets
Loading "integrity_archive.par.vol000+01.par2".
Loaded 1 new packets including 1 recovery blocks
Loading "integrity_archive.par.vol001+02.par2".
Loaded 2 new packets including 2 recovery blocks
Loading "integrity_archive.par.vol003+04.par2".
Loaded 4 new packets including 4 recovery blocks
Loading "integrity_archive.par.vol007+08.par2".
Loaded 8 new packets including 8 recovery blocks
Loading "integrity_archive.par.vol015+16.par2".
Loaded 16 new packets including 16 recovery blocks
Loading "integrity_archive.par.vol031+32.par2".
Loaded 32 new packets including 32 recovery blocks
Loading "integrity_archive.par.vol063+37.par2".
Loaded 37 new packets including 37 recovery blocks
Loading "integrity_archive.par.par2".
No new packets found
    
There are 17 recoverable files and 0 other files.
The block size used was 3812 bytes.
There are a total of 2000 data blocks.
The total size of the data files is 7595275 bytes.
    
Verifying source files:
    
    
Target: "my_data/....." - found.
[...cut here...]
Target: "my_data/....." - found.
Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - damaged. Found 95 of 95 data blocks.
    
Scanning extra files:
  
    
Repair is required.
1 file(s) exist but are damaged.
16 file(s) are ok.
You have 2000 out of 2000 data blocks available.
You have 100 recovery blocks available.
Repair is possible.
You have an excess of 100 recovery blocks.
None of the recovery blocks will be used for the repair.
    
% echo $?
1

Repair usage:

% par2 repair integrity_archive.par.par2      
Loading "integrity_archive.par.par2".
Loaded 36 new packets
Loading "integrity_archive.par.vol000+01.par2".
Loaded 1 new packets including 1 recovery blocks
Loading "integrity_archive.par.vol001+02.par2".
Loaded 2 new packets including 2 recovery blocks
Loading "integrity_archive.par.vol003+04.par2".
Loaded 4 new packets including 4 recovery blocks
Loading "integrity_archive.par.vol007+08.par2".
Loaded 8 new packets including 8 recovery blocks
Loading "integrity_archive.par.vol015+16.par2".
Loaded 16 new packets including 16 recovery blocks
Loading "integrity_archive.par.vol031+32.par2".
Loaded 32 new packets including 32 recovery blocks
Loading "integrity_archive.par.vol063+37.par2".
Loaded 37 new packets including 37 recovery blocks
Loading "integrity_archive.par.par2".
No new packets found
    
There are 17 recoverable files and 0 other files.
The block size used was 3812 bytes.
There are a total of 2000 data blocks.
The total size of the data files is 7595275 bytes.
    
Verifying source files:
    
Target: "my_data/....." - found.
[...cut here...]
Target: "my_data/....." - found.
Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - damaged. Found 95 of 95 data blocks.
    
Scanning extra files:
    
    
Repair is required.
1 file(s) exist but are damaged.
16 file(s) are ok.
You have 2000 out of 2000 data blocks available.
You have 100 recovery blocks available.
Repair is possible.
You have an excess of 100 recovery blocks.
None of the recovery blocks will be used for the repair.
    
    
Wrote 361069 bytes to disk
    
Verifying repaired files:
    
Target: "my_data/Ebooks/Lovecraft/Quete Onirique de Kadath l'Inconnue.epub" - found.
    
Repair complete.
    
% echo $?
0

par2cmdline is only one implementation doing the job, others tools working with PAR archives exists. They should be able to all works with the same PAR files.

Parchive on Wikipedia

Github page

par2cmdline is available in OpenBSD ports in archivers/par2cmdline.

If you find a way to add new files to existing archives, please mail me.

mtree

One can write a little script using mtree (in base system on OpenBSD and FreeBSD) which will create a file with the checksum of every files in the specified directories. If mtree output is different since last time, we can send a mail with the difference. This is a process done in base install of OpenBSD for /etc and some others files to warn you if it changed.

While it’s suited for directories like /etc, in my opinion, this is not the best tool for doing integrity check.

ZFS

I would like to talk about ZFS and data integrity because this is where ZFS is very good. If you are using ZFS, you may not need any other software to take care about your data. When you write a file, ZFS will also store its checksum as metadata. By default, the option “checksum” is activated on dataset, but you may want to disable it for better performance.

There is a command to ask ZFS to check the integrity of the files. Warning: scrub is very I/O intensive and can takes from hours to days or even weeks to complete depending on your CPU, disks and the amount of data to scrub:

# zpool scrub zpool

The scrub command will recompute the checksum of every file on the ZFS pool, if something is wrong, it will try to repair it if possible. A repair is possible in the following cases:

If you have multiple disks like raid-Z or raid-1 (mirror), ZFS will be look on the differents disks if the non corrupted version of the file exists, if it finds it, it will restore it on the disk(s) where it’s corrupted.

If you have set the ZFS option “copies” to 2 or 3 (1 = default), that means that the file is written 2 or 3 time on the disk. Each file of the dataset will be allocated 2 or 3 time on the disk, so take care if you want to use it on a dataset containing heavy files ! If ZFS find thats a version of a file is corrupted, it will check the others copies of it and tries to restore the corrupted file is possible.

You can see the percentage of filesystem already scrubbed with

zfs status zpool

and the scrub can be stopped with

zfs scrub -s zpool

BTRFS

Like ZFS, BTRFS is able to scrub its data and report bit rot, and repair it if data is available in another disk.

To start a scrub, run:

btrfs scrub start /

You can check progress using:

btrfs scrub status /

It’s possible to use btrfs scrub cancel / to stop a scrub, and resume it later with btrfs scrub resume /, however btrfs tries its best to scrub the data without affecting much the responsiveness of the system.

AIDE

Its name is an acronym for “Advanced Intrusion Detection Environment”, it’s an complicated software which can be used to check for bitrot. I would not recommend using it if you only need bitrot detection.

Here is a few hints if you want to use it for checking your file integrity:

/etc/aide.conf

/home/my_data/ R
# Rule definition
All=m+s+i+md5
report_summarize_changes=yes

The config file will create a database of all files in /home/my_data/ (R for recursive). “All” line list the checks we do on each file. For bitrot checking, we want to check modification time, size, checksum and inode of the files. The report_summarize_change displays a list of changes if something is wrong.

This is the most basic config file you can have. Then you will have to run aide to create the database and then run aide to create a new database and compare the two databases. It doesn’t update its database itself, you will have to move the old database and tell it where to found the older database.

My use case

I have different kind of data. On a side, I have static data like pictures, clips, music or things that won’t change over time and the other side I have my mails, documents and folders where the content changes regularly (creation, deletetion, modification). I am able to afford a backup for 100% of my data with some history of the backup on a few days, so I won’t be interested about file repairing.

I want to be warned quickly if a file get corrupted, so I can still get the backup in my history but I don’t keep every versions of my files for too long. I choose to go with the python tool bitrot, it’s very easy to use and it doesn’t become a mess with my folders getting updated often.

I would go with par2cmdline if I could not be able to backup all my data. Having 5% or 10% of redundancy of my files should be enough to restore it in case of corruption without taking too much space.

Port of the week: rss2email

Written by Solène, on 24 January 2017.
Tags: #portoftheweek #unix #email

Comments on Fediverse/Mastodon

This is the kind of Port of the week I like. This is a software I just discovered and fall in love to. The tool r2e which is the port mail/rss2email on OpenBSD is a small python utility that solves a problem: how to deal with RSS feeds?

Until last week, I was using a “web app” named selfoss which was aggregating my RSS feeds and displaying it on a web page, I was able to filter by read/unread/marked and also filter by source. It is a good tool that does the job well but I wanted something that doesn’t rely on a web browser. Here comes r2e !

This simple software will send you a mail for each new entry in your RSS feeds. It’s really easy to configure and set-up. Just look at how I configured mine:

$ r2e new my-address+rss@my-domain.com
$ r2e add "http://undeadly.org/cgi?action=rss"
$ r2e add "https://dataswamp.org/~solene/rss.xml"
$ r2e add "https://www.dragonflydigest.com/feed"
$ r2e add "http://phoronix.com/rss.php"

Add this in your crontab to check new RSS items every 10 minutes:

*/10 * * * * /usr/local/bin/r2e run

Add a rule for my-address+rss to store mails in a separate folder, and you’re done !

NOTE: you can use r2e run –no-send for the first time, it will create the database and won’t send you mails for current items in feeds.

Dovecot: folder appears empty

Written by Solène, on 23 January 2017.
Tags: #email

Comments on Fediverse/Mastodon

Today I encountered an unknown issue to me with my Imap server dovecot. In roundcube mail web client, my Inbox folder appeared empty after being reading a mail. My Android mail client K9-Mail was displaying “IOException:readStringUnti….” when trying to synchronize this folder.

I solved it easily by connecting to my server with SSH, cd-ing into the maildir directory and in the Inbox folder, renamed dovecot.index.log to dovecot.index.log.bak (you can remove it if it fix the problem).

And now, mails are back. This is the very first time I have a problem of this kind with dovecot…

New cl-yag version

Written by Solène, on 21 January 2017.
Tags: #lisp #cl-yag

Comments on Fediverse/Mastodon

Today I just updated my tool cl-yag that implies a slightly change on my website. Now, on the top of this blog, you can see a link “Index of articles”. This page only display articles titles, without any text from the article.

Cl-yag is a tool to generate static website like this one. It’s written in Common LISP. For reminder, it’s also capable of producing both html and gopher output now.

If you don’t know what Gopher is, you will learn a lot reading the following links Wikipedia : Gopher (Protocol) and Why is gopher still relevant

Let's encrypt on OpenBSD in 5 minutes

Written by Solène, on 20 January 2017.
Tags: #security #openbsd70 #openbsd

Comments on Fediverse/Mastodon

Let’s encrypt is a free service which provides free SSL certificates. It is fully automated and there are a few tools to generate your certificates with it. In the following lines, I will just explain how to get a certificate in a few minutes. You can find more informations on Let’s Encrypt website.

To make it simple, the tool we will use will generate some keys on the computer, send a request to Let’s Encrypt service which will use http challenging (there are also dns and another one kind of challenging) to see if you really own the domain for which you want the certificate. If the challenge process is ok, you have the certificate.

Please, if you don’t understand the following commands, don’t type it.

While the following is right for OpenBSD, it may change slightly for others systems. Acme-client is part of the base system, you can read the man page acme-client(1).

Prepare your http server

For each certificate you will ask a certificate, you will be challenged for each domain on the port 80. A file must be available in a path under “/.well-known/acme-challenge/”.

You must have this in your httpd config file. If you use another web server, you need to adapt.

server "mydomain.com" {
    root "/empty"
	listen on * port 80
	location "/.well-known/acme-challenge/*" {
		root { "/acme/" , request strip 2 }
	}
}

The request strip 2 part is IMPORTANT. (I’ve lost 45 minutes figuring out why root “/acme/” wasn’t working.)

Prepare the folders

As stated in acme-client man page and if you don’t need to change the path. You can do the following commands with root privileges :

# mkdir /var/www/acme
# mkdir -p /etc/ssl/acme/private /etc/acme
# chmod 0700 /etc/ssl/acme/private /etc/acme

Request the certificates

As root, in the acme-client sources folder, type the following the generate the certificates. The verbose flag is interesting and you will see if the challenging step work. If it doesn’t work, you should try manually to get a file like with the same path tried from Let’s encrypt, and try again the command when you succeed.

$ acme-client -vNn mydomain.com www.mydomain.com mail.mydomain.com

Use the certificates

Now, you can use your SSL certificates for your mail server, imap server, ftp server, http server…. There is a little drawback, if you generate certificates for a lot of domains, they are all written in the certificate. This implies that if someone visit one page, look at the certificate, this person will know every domain you have under SSL. I think that it’s possible to ask every certificate independently but you will have to play with acme-client flags and make some kind of scripts to automatize this.

Certificate file is located at /etc/ssl/acme/fullchain.pem and contains the full certification chain (as its name is explicit). And the private key is located at /etc/ssl/acme/private/privkey.pem.

Restart the service with the certificate.

Renew certificates

Certificates are valid for 3 months. Just type

./acme-client mydomain.com www.mydomain.com mail.mydomain.com

Restart your ssl services.

EASY !

How to use ssh tramp on Emacs Windows?

Written by Solène, on 18 January 2017.
Tags: #emacs #windows

Comments on Fediverse/Mastodon

If you are using emacs under Microsoft Windows and you want to edit remote files through SSH, it’s possible to do it without using Cygwin. Tramp can use the tool “plink” from putty tools to do ssh.

What you need is to get “plink.exe” from the following page and get it into your $PATH, or choose the installer which will install all putty tools.

Putty official website

Then, edit your emacs file to add the following lines to tell it that you want to use plink when using tramp

(require 'tramp)
(set-default 'tramp-default-method "plink")

Now, you can edit your remote files, but you will need to type your password. I think that in order to get password-less with ssh keys, you would need to use putty key agent.

Convert mailbox to maildir with dovecot

Written by Solène, on 17 January 2017.
Tags: #unix #email

Comments on Fediverse/Mastodon

I have been using mbox format for a few years on my personal mail server. For those who don’t know what mbox is, it consists of only one file per folder you have on your mail client, each file containing all the mails of the corresponding folder. It’s extremely ineficient when you backup the mail directory because it must copy everything each time. Also, it reduces the system cache possibility of the server because if you have folders with lots of mails with attachments, it may not be cached.

Instead, I switched to maildir, which is a format where every mail is a regular file on the file system. This takes a lot of inodes but at least, it’s easier to backup or to deal with it for analysis.

Here how to switch from mbox to maildir with a dovecot tool.

# dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox

That’s all ! In this case, my mbox folder was ~/mail/ and my INBOX file was ~/mail/inbox. It tooks me some time to find where my INBOX really was, at first I tried a few thing that didn’t work and tried a perl convert tool named mb2md.pl which has been able to extract some stuff but a lot of mails were broken. So I have been going back getting dsync working.

If you want to migrate, the whole process looks like:

# service smtpd stop
    
modify dovecot/conf.d/10-mail.conf, replace the first line
mail_location = mbox:~/mail:INBOX=/var/mail/%u   # BEFORE
mail_location = maildir:~/maildir                # AFTER
    
# service dovecot restart
# dsync -u solene mirror mbox:~/mail/:INBOX=~/mail/inbox
# service smtpd start

Port of the week: entr

Written by Solène, on 07 January 2017.
Tags: #unix

Comments on Fediverse/Mastodon

entr is a command line tool that let you run arbitrary command on file change. This is useful when you are doing something that requires some processing when you modify it.

Recently, I have used it to edit a man page. At first, I had to run mandoc each time I modified to file to check the render. This was the first time I edited a man page so I had to modify it a lot to get what I wanted. I remembered about entr and this is how you use it:

$ ls stagit.1 | entr mandoc /_

This simple command will run “mandoc stagit.1” each time stagit.1 is modified. The file names must be given by stdin to entr, and then use the characters sequence /_ to replace the names (like {} in find).

The man page of entr is very well documented if you need more examples.

Emacs 25: save cursor position

Written by Solène, on 08 December 2016.
Tags: #emacs

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Since I upgraded to Emacs 25 it was no longer saving my last cursor position in edited file. This is a feature I really like because I often fire and close emacs rather than keeping it opened.

Before (< emacs 25)

(setq save-place-file "~/.emacs.d/saveplace") 
(setq-default save-place t) 
(require 'saveplace)

Emacs 25

(save-place-mode t)
(setq save-place-file "~/.emacs.d/saveplace") 
(setq-default save-place t)

That’s all :)

Port of the week: dnscrypt-proxy

Written by Solène, on 19 October 2016.
Tags: #unix #security #portoftheweek

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2020 Update

Now, unwind on OpenBSD and unbound can support DNS over TLS or DNS over HTTPS, dnscrypt lost a bit of relevance but it’s still usable and a good alternative.

Dnscrypt

Today I will talk about net/dnscrypt-proxy. This let you encrypt your DNS traffic between your resolver and the remote DNS recursive server. More and more countries and internet provider use DNS to block some websites, and now they tend to do “man in the middle” with DNS answers, so you can’t just use a remote DNS you find on the internet. While a remote dnscrypt DNS server can still be affected by such “man in the middle” hijack, there is a very little chance DNS traffic is altered in datacenters / dedicated server hosting.

The article also deal with unbound as a dns cache because dnscrypt is a bit slow and asking multiple time the same domain in a few minutes is a waste of cpu/network/time for everyone. So I recommend setting up a DNS cache on your side (which can also permit to use it on a LAN).

At the time I write this article, their is a very good explanation about “how to install it” is named dnscrypt-proxy-1.9.5p3 in the folder /usr/local/share/doc/pkg-readmes/. The following article is made from this file. (Article updated at the time of OpenBSD 6.3)

While I write for OpenBSD this can be easily adapted to anthing else Unix-like.

Install dnscrypt

# pkg_add dnscrypt-proxy

Resolv.conf

Modify your resolv.conf file to this

/etc/resolv.conf :

nameserver 127.0.0.1
lookup file bind
options edns0

When using dhcp client

If you use dhcp to get an address, you can use the following line to force having 127.0.0.1 as nameserver by modifying dhclient config file. Beware, if you use it, when upgrading the system from bsd.rd, you will get 127.0.0.1 as your DNS server but no service running.

/etc/dhclient.conf :

supersede domain-name-servers 127.0.0.1;

Unbound

Now, we need to modify unbound config to tell him to ask DNS at 127.0.0.1 port 40. Please adapt your config, I will just add what is mandatory. Unbound configuration file isn’t in /etc because it’s chrooted

/var/unbound/etc/unbound.conf:

server:
    # this line is MANDATORY
    do-not-query-localhost: no

forward-zone:
    name: "."
    forward-addr: 127.0.0.1@40
	# address dnscrypt listen on

If you want to allow other to resolv through your unbound daemon, please see parameters interface and access-control. You will need to tell unbound to bind on external interfaces and allow requests on it.

Dnscrypt-proxy

Now we need to configure dnscrypt, pick a server in the following LIST /usr/local/share/dnscrypt-proxy/dnscrypt-resolvers.csv, the name is the first column.

As root type the following (or use doas/sudo), in the example we choose dnscrypt.eu-nl as a DNS provider

# rcctl enable dnscrypt_proxy
# rcctl set dnscrypt_proxy flags -E -m1 -R dnscrypt.eu-nl -a 127.0.0.1:40
# rcctl start dnscrypt_proxy

Conclusion

You should be able to resolv address through dnscrypt now. You can use tcpdump on your external interface to see if you see something on udp port 53, you should not see traffic there.

If you want to use dig hostname -p 40 @127.0.0.1 to make DNS request to dnscrypt without unbound, you will need net/isc-bind which will provide /usr/local/bin/dig. OpenBSD base dig can’t use a port different than 53.

How to publish a git repository on http

Written by Solène, on 07 October 2016.
Tags: #unix #git #versioning

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Here is an how-to in order to make a git repository available for cloning through a simple http server. This method only allow people to fetch the repository, not to push. I wanted to set-up this to get my code, I don’t plan to have any commit on it from other people at this time so it’s enough.

In a folder publicly available from your http server clone your repository in bare mode. As explained in the https://git-scm.com/book/tr/v2/Git-on-the-Server-The-Protocols:

$ cd /var/www/htdocs/some-path/
$ git clone --bare /path/to/git_project gitproject.git
$ cd gitproject.git
$ git update-server-info
$ mv hooks/post-update.sample hooks/post-update
$ chmod o+x hooks/post-update

Then you will be able to clone the repository with

$ git clone https://your-hostname/some-path/gitproject.git

I’ve lost time because I did not execute git update-server-info so the clone wasn’t possible.

Port of the week: rlwrap

Written by Solène, on 04 October 2016.
Tags: #unix #shell #portoftheweek

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Today I will present misc/rlwrap which is an utility tool when you use some command-line software which doesn’t provide you a nice readline input. By using rlwrap, you will be able to use telnet, a language REPL or any command-line tool where you input text with an history of what you type, ability to use emacs bindings like C-a C-e M-Ret etc… I use it often with telnet or sbcl.

Usage :

$ rlwrap telnet host port

Common LISP: How to open an SSL / TLS stream

Written by Solène, on 26 September 2016.
Tags: #lisp #networking

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Here is a tiny code to get a connection to an SSL/TLS server. I am writing an IRC client and an IRC bot too and it’s better to connect through a secure channel.

This requires usocket and cl+ssl:

(usocket:with-client-socket (socket stream *server* *port*)
  (let ((ssl-stream (cl+ssl:make-ssl-client-stream stream
    						   :external-format '(:iso-8859-1 :eol-style :lf)
    						   :unwrap-stream-p t
    						   :hostname *server*)))
    (format ssl-stream "hello there !~%")
    (force-output ssl-stream)))

Android phone and Unix

Written by Solène, on 06 September 2016.
Tags: #android #emacs

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If you have an android Phone, here are two things you may like:

Org-mode <=> Android

First is the MobileOrg app to synchronize your calendar/tasks between your computer org-mode files and your phone. I am using org-mode since a few months, I think I do pretty basics things with it like having a todo list with a deadline for each item. Having it in my phone calendar is a good enhancement. I can also add todo items from my phone to show it on my computer.

The phone and your computer get synced by publishing a special format of org files for the mobile on a remote server. Mobile Org supports ssh, webdav, dropbox or sdcard. I’m using ssh because I own a server and I can reliabily have my things connected together there on a dedicated account. Emacs will then use tramp to publish/retrieve the files.

Official MobileOrg website

MobileOrg on Google Play

Read/Write sms from a remote place

Second useful thing I like with my android phone is being able to write and send sms (+ some others things but I was most interested by SMS) from my computer. A few services already exists but they work with “cloud” logic and I don’t want my phone to be connected to one more service. The MAXS app provides me what I need : ability to read/write the sms of my phone from the computer without web browser and relying on my own services. MAXS connects the phone to a XMPP account and you set a whitelist of XMPP mails able to send commands, that’s all. Here are a few examples of use:

To write a SMS I just need to speak to the jabber account of my phone and write

sms send firstname lastname  hello how are you ?

Be careful, there are 2 spaces after the lastname ! I think it’s like this so MAXS can make easily the difference between the name and the message.

I can also reply quickly to the last contacted person

reply to Yes I'm answering from my computer

To read the last n sms

sms read n

It’s still not perfect because sometimes it lose connectivity and you can’t speak with it anymore but from the project author it’s not a problem seen on every phone. I did not have the time yet to report exactly the problem (I need to play with Android Debug Bridge for that). If you want to install MAXS, you will need a few app from the store to get it working. First, you will need MAXS main and MAXS transport (a plugin to use XMPP) and then plugins for the differents commands you want, so, maybe, smsread and smswrite. Check their website for more informations.

As presenter earlier on my website, I use profanity as XMPP client. It’s a light and easy to configure/use console client.

Official MAXS Website

MAXS on Google Play

How to kill processes by their name

Written by Solène, on 25 August 2016.
Tags: #unix

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If you want to kill a process by its name instead of its PID number, which is easier if you have to kill processes from the same binary, here are the commands depending of your operating system:

FreeBSD / Linux

$ killall pid_name

OpenBSD

$ pkill pid_name

Solaris

Be careful with Solaris killall. With no argument, the command will send a signal to every active process, which is not something you want.

$ killall pid_name

Automatically mute your Firefox tab

Written by Solène, on 17 August 2016.
Tags: #firefox

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At work I have the sound of my laptop not muted because I need sound from time to time. But browsing the internet with Firefox can sometime trigger some undesired sound, very boring in the office. There is the extension Mute Tab to auto-mute a new tab on Firefox so it won’t play sound. The auto-mute must be activated in the plugin options, it’s un-checked by default.

You can find it here, no restart required: Firefox Mute Tab addon

I also use FlashStopper which block by default flash and HTML5 videos, so you can click on it to activate them, it doesn’t autoplay.

Firefox FlashStopper addon

Port of the week: pwgen

Written by Solène, on 12 August 2016.
Tags: #security #portoftheweek

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I will talk about security/pwgen for the current port of the week. It’s a very light executable to generate passwords. But it’s not just a dumb password generator, it has options to choose what kind of password you want.

Here is a list of options with their flag, you will find a lot more in the nice man page of pwgen:

  • -A : don’t use capital letters
  • -B : don’t use characters which could be missread (O/0, I/l/1 …)
  • -v : don’t use vowels
  • etc…

You can also use a seed to generate your “random” password (which aren’t very random in this case), you may need it for some reason to be able to reproduce password you lost for a ftp/http access for example.

Example of pwgen output generating 5 password of 10 characters. Using -1 parameter so it will only display one password per line, otherwise it display a grid (on column and multiple lines) of passwords.

$ pwgen -1 10 5
fohchah9oP
haNgeik0ee
meiceeW8ae
OReejoi5oo
ohdae2Eisu

Website now compatible gopher !

Written by Solène, on 11 August 2016.
Tags: #gopher #networking #lisp

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My website is now available with Gopher protocol ! I really like this protocol. If you don’t know it, I encourage you reading this page : Why is Gopher still relevant?.

This has been made possible by modifying the tool generating the website pages to make it generating gopher compatible pages. This was a bit of work but I am now proud to have it working.

I have also made a “big” change into the generator, it now rely on a “markdown-to-html” tool which sadden me a bit. Before that, I was using ham-mode in emacs which was converting html on the fly to markdown so I can edit in markdown, and was exporting into html on save. This had pros and cons. Nothing more than a lisp interpreter was needed on the system generating the files, but I was sometimes struggling with ham-mode because the conversion was destructive. Multiple editing in a row of the same file was breaking code blocks, because it wasn’t exported the same way each time until it wasn’t a code block anymore. There are some articles that I update sometimes to keep it up-to-date or fix an error in it, and it was boring to fix the code everytime. Having the original markdown text was mandatory for gopher export, and is now easier to edit with any tool.

There is a link to my gopher site on the right of this page. You will need a gopher client to connect to it. There is an android client working, also Firefox can have an extension to become compatible (gopher support was native before it have been dropped). You can find a list of clients on Wikipedia.

Gopher is nice, don’t let it die.

Port of the week: feh

Written by Solène, on 08 August 2016.
Tags: #portoftheweek

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Today I will talk about graphics/feh, it’s a tool to view pictures and it can also be used to set an image as background.

I use this command line, invoked by stumpwm when my session starts so I can a nice background with cubes :)

$ feh --bg-scale /home/solene/Downloads/cubes.jpg

feh as a lot of options and is really easy to use, I still prefer sxiv for viewing but I use feh for my background.

Port of the week: Puddletag

Written by Solène, on 20 July 2016.
Tags: #portoftheweek

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If you ever need to modify the tags of your music library (made of MP3s) I would recommend you audio/puddletag. This tool will let you see all your music metadata like a spreadsheet and just modify the cells to change the artist name, title etc… You can also select multiple cells and type one text and it will be applied on all the selected cells. There is also a tool to extract data from the filename with a regex. This tool is very easy and pleasant to use.

There is an option in the configuration panel that is good to be aware of, by default, when you change the tag of a file, the modification time isn’t changed, so if you use some kind of backup relying on the modification time it won’t be synchronized. In the configuration panel, you will find an option to check which will bump the modification timestamp when you change a tag on a song.

Port of the week: Profanity

Written by Solène, on 12 July 2016.
Tags: #portoftheweek #networking

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1. Introduction §

Profanity official website

Profanity is a command-line ncurses based XMPP (Jabber) client. It's easy to use and seem inspired from irssi for the interface. It's available on OpenBSD as a package named "profanity".

It's really easy to use and the documentation on its website is really clear. It supports all main XMPP features including OMEMO / OTR / GPG for end-to-end encryption.

2. How to use (simple introduction) §

To log-in, just type **/connect myusername@mydomain** and after the password prompt, you will be connected. Easy.

Stop being tracked by Google search with Firefox

Written by Solène, on 04 July 2016.
Tags: #security #web

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When you use google search and you click on a link, you a redirected on a google server that will take care of saving your navigation choice from their search engine into their database.

  1. This is bad for your privacy
  2. This slow the process of using the search engine because you have a redirection (that you don’t see) when you want to visit a link

There is a firefox extension that will fix the links in the results of the search engine so when you click, you just go on the website without saying “hello Google I clicked there”: Google Search Link Fix

You can also use another web engine if you don’t like Google. I keep it because I have best results when searching technical. I tried to use Yahoo, Bing, Exalead, Qwant, Duck duck go, each one for a few days and Google has the bests results so far.

Port of the week: OpenSCAD

Written by Solène, on 04 July 2016.
Tags: #portoftheweek

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OpenSCAD is a software for creating 3D objects like a programming language, with the possibility to preview your creation.

I am personaly interested in 3D things, I have been playing with 3ds Max and Blender for creating 3d objects but I never felt really comfortable with them. I discovered pov-ray a few years ago which is used to create rendered pictures instead of creating objects. Pov-ray use its own “programming language” to describe the scene and make the render. Now, I have a 3D printer and I would like to create things to print, but I don’t like the GUI stuff of Blender and Pov-ray don’t create objects, so… OpenSCAD ! This is the pov-ray of objects !

Here is a simple example that create an empty box (difference of 2 cubes) and a screw propeller:

width = 3;
height = 3;
depth = 6;
thickness = 0.2;
    
difference() {
    cube( [width,depth,height], true);
    
translate( [0,0,thickness] )
    cube( [width-thickness, depth-thickness, height], true);
}
    
translate( [ width , 0 , 0 ])
    linear_extrude(twist = 400, height = height*2)
        square(2,true);

The following picture is made from the code above:

openscad
openscad

There are scad-mode and scad-preview for emacs for editing OpenSCAD files. scad-mode will check the coloration/syntax and scad-preview will create the OpenScad render inside a Emacs pane. Personaly, I use OpenSCAD opened in some corner of the screen with option set to render on file change, and I edit with emacs. Of course you can use any editor, or the embedded editor which is a Scintilla one which is pretty usable.

OpenSCAD website

OpenSCAD gallery

Port of the week: arandr

Written by Solène, on 27 June 2016.
Tags: #portoftheweek

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Today the Port of the week is x11/arandr, it’s a very simple tool to set-up your screen display when using multiple monitors. It’s very handy when you want to make something complicated or don’t want to use xrandr in command line. There is not much to say because it’s very easy to use!

It can generates your current configuration as a script that you will find under the ~/.screenlayout/ repertory. This is quite useful to configure your screens from your ~/.xsession file in case a monitor is connected.

xrandr | grep "HDMI-2 connected" && .screenlayout/dual-monitor.sh

If HDMI-2 has a screen connected, when I log-in my session, I will have my dual-monitor setup!

Port of the week: x2x

Written by Solène, on 23 June 2016.
Tags: #portoftheweek

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Port of the week is now presenting you x2x which stands for X to X connection. This is a really tiny tool in one executable file that let you move your mouse and use your keyboard on another X server than yours. It’s like the other tool synergy but easier to use and open-source (I think synergy isn’t open source anymore).

If you want to use the computer on your left, just use the following command (x2x must be installed on it and ssh available)

$ ssh -CX the_host_address "x2x -west -to :0.0"

and then you can move your cursor to the left of your screen and you will see that you can use your cursor or type with the keyboard on your other computer ! I am using it to manage a wall of screen made of raspberry Pi first generation. I used to connect to it with VNC but it was very very slow.

Git cheat sheet

Written by Solène, on 08 June 2016.
Tags: #cheatsheet #git #versioning

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Here is my git cheat sheet ! Because I don’t like git I never remember how to do X or Y with it so I need to write down simple commands ! (I am used to darcs and mercurial but with the “git trend” I need to learn it and use it).

Undo uncommited changes on a tracked file

$ git reset --hard

Get the latest version before working

$ git pull

Make a commit containing all tracked files

$ git commit -m "Commit message" -a

Send the commit to the repository

$ git push

How to send html signature in mu4e

Written by Solène, on 07 June 2016.
Tags: #email #emacs

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I switched to mu4e to manage my mails at work, and also to send mails. But in our corporation we all have a signature that include our logo and some hypertext links, so I couldn’t just insert my signature and be done with that. There is a simple way to deal with this problem, I fetched the html part of my signature (which include an image in base64) and pasted it into my emacs config file this way.

(setq mu4e-compose-signature 
  "<#part type=text/html><html><body><p>Hello ! I am the html signature which can contains anything in html !</p></body></html><#/part>" )

I pasted my signature instead of the hello world text of course, but you only have to use the part tag and you are done ! The rest of your mails will be plain text, except this part.

My Stumpwm config on OpenBSD

Written by Solène, on 06 June 2016.
Tags: #window-manager #lisp

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I want to talk about stumpwm, a window manager written in Common LISP. I think one must at least like emacs to like stumpwm. Stumpwm is a tiling window manager one which you create “panes” on the screen like windows on Emacs. A single pane takes 100% of the screen, then you can split it into 2 panes vertically or horizontally and resize it, and you can split again and again. There is no “automatic” tiling. By default, if you have ONE pane, you will only have ONE window displayed, this is a bit different that others tiling wm I had tried. Also, virtual desktops are named groups, nothing special here, you can create/delete groups and rename it. Finally, stumpwm is not minimalistic.

To install it, you need to get the sources of stumpwm, install a common lisp interpreter (sbcl, clisp, ecl etc…), install quicklisp (which is not in packages), install the quicklisp packages cl-ppcre and clx and then you can compile stumpwm, that will produce a huge binary which embedded a common lisp interpreter (that’s a way to share common lisp executables, the interpreter can create an executable from itself and include the files you want to execute). I would like to make a package for OpenBSD but packaging quicklisp and its packages seems too difficult for me at the moment.

Here is my config file in ~/.stumpwmrc.

Updated: 23th january 2018

(defun chomp(text) (subseq text 0 (- (length text) 1)))
(defmacro cmd(command) `(progn `(:eval (chomp (stumpwm:run-shell-command ,,command t)))))
    
(defun get-latence()
  (let ((now (get-universal-time)))
    (when (> (- now *latence-last-update* ) 30)
      (setf *latence-last-update* now)
      (when (probe-file "/tmp/latenceresult")
        (with-open-file (x "/tmp/latenceresult"
                           :direction :input)
          (setf *latence* (read-line x))))))
  *latence*)
    
(defvar *latence-last-update* (get-universal-time))
(defvar *latence* "nil")
    
    
(set-module-dir "~/dev/stumpwm-contrib/")
(stumpwm:run-shell-command "setxkbmap fr")
(stumpwm:run-shell-command "feh --bg-fill red_damask-wallpaper-1920x1080.jpg")
    
(defvar color1 "#886666")
(defvar color2 "#222222")
    
(setf
 stumpwm:*mode-line-background-color* color2 
 stumpwm:*mode-line-foreground-color* color1
 stumpwm:*mode-line-border-color* "#555555"
 stumpwm:*screen-mode-line-format* (list "%g | %v ^>^7 %B | " '(:eval (get-latence)) "ms %d    ")
 stumpwm:*mode-line-border-width* 1
 stumpwm:*mode-line-pad-x* 6
 stumpwm:*mode-line-pad-y* 1
 stumpwm:*mode-line-timeout* 5
 stumpwm:*mouse-focus-policy* :click
 ;;stumpwm:*group-format* "%n·%t
 stumpwm:*group-format* "%n"
 stumpwm:*time-modeline-string* "%H:%M"
 stumpwm:*window-format* "^b^(:fg \"#7799AA\")<%25t>"
 stumpwm:*window-border-style* :tight
 stumpwm:*normal-border-width* 1
 )
    
    
(stumpwm:set-focus-color "#7799CC")
(stumpwm:grename "Alpha")
(stumpwm:gnewbg "Beta")
(stumpwm:gnewbg "Tau")
(stumpwm:gnewbg "Pi")
(stumpwm:gnewbg "Zeta")
(stumpwm:gnewbg "Teta")
(stumpwm:gnewbg "Phi")
(stumpwm:gnewbg "Rho")
    
(stumpwm:toggle-mode-line (stumpwm:current-screen) (stumpwm:current-head))
    
(set-prefix-key (kbd "M-a"))
    
(define-key *root-map* (kbd "c")            "exec urxvtc")
(define-key *root-map* (kbd "RET")          "move-window down")
(define-key *root-map* (kbd "z")            "fullscreen")
    
(define-key *top-map* (kbd "M-&")           "gselect 1")
(define-key *top-map* (kbd "M-eacute")      "gselect 2")
(define-key *top-map* (kbd "M-\"")          "gselect 3")
(define-key *top-map* (kbd "M-quoteright")  "gselect 4")
(define-key *top-map* (kbd "M-(")           "gselect 5")
(define-key *top-map* (kbd "M--")           "gselect 6")
(define-key *top-map* (kbd "M-egrave")      "gselect 7")
(define-key *top-map* (kbd "M-underscore")  "gselect 8")
					    
(define-key *top-map* (kbd "s-l")           "exec slock")
(define-key *top-map* (kbd "s-t")           "exec urxvtc")
(define-key *top-map* (kbd "M-S-RET")       "exec urxvtc")
(define-key *top-map* (kbd "M-C")           "exec urxvtc")
    
(define-key *top-map* (kbd "s-s")           "exec /home/solene/dev/screen_up.sh")
    
(define-key *top-map* (kbd "s-Left")        "gprev")
(define-key *top-map* (kbd "s-Right")       "gnext")
    
(define-key *top-map* (kbd "M-ISO_Left_Tab")"other")
(define-key *top-map* (kbd "M-TAB")         "fnext")
(define-key *top-map* (kbd "M-twosuperior") "next-in-frame")
    
(load-module "battery-portable")
(load-module "stumptray")

I use a function to get latency from a script that is started every 20 seconds to display the network latency or nil if I don’t have internet access.

I use rxvt-unicode daemon (urxvtd) as a terminal emulator, so the terminal command is urxvtc (for client), it’s lighter and faster to load.

I also use a weird “alt+tab” combination:

  • Alt+tab switch between panes
  • Alt+² (the key above tab) circles windows in the current pane
  • Alt+Shift+Tab switch to the previous windows selected

StumpWM website

Port of the week: mbuffer

Written by Solène, on 31 May 2016.
Tags: #portoftheweek #networking

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This Port of the week is a bit special because sadly, the port isn’t available on OpenBSD. The port is mbuffer (which you can find in misc/mbuffer).

I discovered it while looking for a way to enhance one of my network stream scripts. I have some scripts that get a dump of a postgresql base through SSH, copy it from stdin to a file with tee and send it out to the local postgres, the command line looks like

$ ssh remote-base-server "pg_dump my_base | gzip -c -f -" | gunzip -f | tee dumps/my_base.dump | psql my_base

I also use the same kind of command to receive a ZFS snapshot from another server.

But there is an issue, the end server is relatively slow, postgresql and ZFS will eat lot of data from stdin and then it will stop for sometimes writing on the disk, when they are ready to take new data, it’s slow to fill them. This is where mbuffer takes places. This tool permit to add a buffer that will take data from stdin and fill its memory (that you set on the command line), so when the slowest part of the command is ready to take data, mbuffer will empty its memory into the pipe, so the slowlest command isn’t waiting to get filled before working again.

The new command looks like that for a buffer of 300 Mb

ssh remote-base-server "pg_dump my_base | gzip -c -f -" |  gunzip -f | tee dumps/my_base.dump | mbuffer -s 8192 -m 300M | psql my_base

mbuffer also comes with a nice console output, showing

  • bandwith in

  • bandwith out

  • percentage/consumption of memory filled

  • total transfered

    in @ 1219 KiB/s, out @ 1219 KiB/s, 906 MiB total, buffer 0% full

In this example the server is too fast so there is no wait, the buffer isn’t used (0% full).

mbuffer can also listen on TCP, unix socket and have a lot of parameters that I didn’t try, if you think that can be useful for you, just go for it !

FreeBSD 11 and Perc H720P Mini raid controller

Written by Solène, on 25 May 2016.
Tags: #freebsd11 #hardware

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I had a problem with my 3 latests R430 Dell server which all have a PERC H730P Mini raid controller. The installer could barely works and slowly, and 2 servers were booting and crashing with FS corruption while the latest just didn’t boot and the raid was cleared.

It is a problem with a driver of the raid controller. I don’t understand exatly the problem but I found a fix.

From man page mfi(4)

A tunable is provided to adjust the mfi driver's behaviour when attaching
to a card.  By default the driver will attach to all known cards with
high probe priority.  If the tunable hw.mfi.mrsas_enable is set to 1,
then the driver will reduce its probe priority to allow mrsas to attach
to the card instead of mfi.

In order to install the system, you have to set hw.mfi.mrsas_enable=1 on the install media, and set this on the installed system before booting it.

There are two ways for that:

  • if you use a usb media, you can mount it and edit /boot/loader.conf and add hw.mfi.mrsas_enable=1
  • at the boot screen with the logo freebsd, choose 3) Espace to boot prompt, type set hw.mfi.mrsas_enable=1 and boot

You will have to edit /boot/loader.conf to add the line on the installed system from the live system of the installer.

I have been struggling a long before understanding the problem. I hope this message could save time to somebody else.

Port of the week: rdesktop

Written by Solène, on 20 May 2016.
Tags: #portoftheweek

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This week we will have a quick look at the tool rdesktop. Rdesktop is a RDP client (RDP stands for Remote Desktop Protocol) which is used to share your desktop with another machine. RDP is a Microsoft thing and it’s most used on Windows.

I am personally using it because sometimes I need to use Microsoft Word/Excel or Windows only software and I have a dedidated virtual machine for this. So I use rdesktop to connect in fullscreen to the virtual machine and I can work on Windows. The RDP protocol is very efficient, on LAN network there is no lag. I appreciate much more using the VM with RDP than VNC.

You can also have RDP servers within virtual machines. VirtualBox let you have (with an additional package to add on the host) RDP server for a VM. Maybe VmWare provides RDP servers too. I know that Xen and KVM can give access through VNC or Spice but no RDP.

For its usage, if you want to connect to a RDP server whose IP address is 192.168.1.100 in fullscreen with max quality, type:

$ rdesktop -f -x 0x80 192.168.1.100

The -x 0x80 bit is needed to set the quality at maximum. If the machine needs username and password you can add -u my_user -p my_plaintext_pass to login automatically. I have an alias in my zsh shell, I just type “windows” and I get logged in in fullscreen to the windows machine.

To exit fullscreen type ctrl+alt+return to switch to windowed mode and again to go in fullscreen mode. I wasn’t able to remember the keyboard shortcut the first times and was stuck in Windows ! ;-)

In the OpenBSD ports tree, check x11/rdesktop.

Mbsync and imap login problem

Written by Solène, on 17 May 2016.
Tags: #solved #email

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I have not found any answer about this so I share my fixed. I wanted to use mbsync with one IMAP server and encountered the following error.

IMAP command 'AUTHENTICATE DIGEST-MD5' returned an error: NO Authentication failed

A fix is to add the following to your ~/.mbsyncrc IMAPAccount declaration.

AuthMechs LOGIN

Using LOGIN instead of DIGEST-MD5 is still secure if you have an encrypted connection (IMAPS or STARTTLS). The login will be given plaintext inside the connection.

Resize live UFS filesystem on FreeBSD 11

Written by Solène, on 17 May 2016.
Tags: #freebsd11

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I am using FreeBSD in virtual machines and sometimes I need to increase the disk capacity of the storage. From your VM Host, increase the capacity of the storage backend, then on the FreeBSD system (10.3 when writing), you should see this in the last line of dmesg.

GEOM_PART: vtbd0 was automatically resized.
  Use `gpart commit vtbd0` to save changes or `gpart undo vtbd0` to revert them.

Here is the gpart show output on the system:

>       34  335544253  vtbd0  GPT  (160G)
        34       1024      1  freebsd-boot  (512K)
      1058  159382528      2  freebsd-ufs  (76G)
 159383586    8388540      3  freebsd-swap  (4.0G)
 167772126  167772161         - free -  (80G)

The process is a bit harder here because I have my partition swap at the end of the storage, so if I want to increase the size of the ufs partition, I will need to remove the swap partition, increase the data partition and recreate the swap. This is not that hard but having the freebsd-ufs partition at the end would have been easier.

  1. swapoff the device : swapoff /dev/vtbd0p3
  2. delete the swap partition : gpart delete -i 3 vtbd0
  3. resize the freebsd-ufs partition : gpart resize -i 2 -a 4k -s 156G vtbd0
  4. create the swap : gpart add -t freebsd-swap -a 4k vtbd0
  5. swapon : swapon /dev/vtbd0p3
  6. tell UFS to resize : growfs /

If freebsd-ufs was the latest in the gpart order, only steps 3 and 6 would have been necessary.

Sources: FreeBSD Handbook and gpart(8)

Git push to non-bare repository

Written by Solène, on 17 May 2016.
Tags: #git #versioning #solved

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Hello

You have a git repository where you work in, and you would like to work on a clone of it and push the data back to it ? You may encounter issues if your git repository isn’t a bare one. I have been facing this problem by using gitit, which works with a non-bare git repository.

What is a bare git repository ?

Here is how to create a bare repository and what it looks like.

$ git init --bare repo 
$ ls -a repo/
.            HEAD         config       hooks        objects
..           branches     description  info         refs

You can’t work in this, but this is the kind of repository that should be used to store/push/clone etc..

What is a non-bare git repository ?

Here is how to create a non-bare repository and what it looks like.

$ git init repo2
$ ls -a repo2
.    ..   .git

You may use this one for local use, but you may want to clone it later, and work with this repository and doing push/pull. That’s how gitit works, it has a folder “wikidata” that should be initiated as git, and it will works locally. But if you want to clone it on your computer, work on the documentation and then push your changes to gitit, you may get this error when pushing :

Problem when pushing

I cloned the repository, made changes, committed and now I want to push, but no…

Décompte des objets: 3, fait.
Écriture des objets: 100% (3/3), 232 bytes | 0 bytes/s, fait.
Total 3 (delta 0), reused 0 (delta 0)
remote: error: refusing to update checked out branch: refs/heads/master
remote: error: By default, updating the current branch in a non-bare repository
remote: error: is denied, because it will make the index and work tree inconsistent
remote: error: with what you pushed, and will require 'git reset --hard' to match
remote: error: the work tree to HEAD.
remote: error: 
remote: error: You can set 'receive.denyCurrentBranch' configuration variable to
remote: error: 'ignore' or 'warn' in the remote repository to allow pushing into
remote: error: its current branch; however, this is not recommended unless you
remote: error: arranged to update its work tree to match what you pushed in some
remote: error: other way.
remote: error: 
remote: error: To squelch this message and still keep the default behaviour, set
remote: error: 'receive.denyCurrentBranch' configuration variable to 'refuse'.
 ! [remote rejected] master -> master (branch is currently checked out)

git is unhappy, I can’t push

Solution

You can fix this “problem” by changing a config in the server repository with this command :

$ git config --local receive.denyCurrentBranch updateInstead

Now you should be able to push to your non-bare repository.

Source: Stack Overflowk link where I found the solution

Port of the week: sxiv

Written by Solène, on 13 May 2016.
Tags: #portoftheweek

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This week I will talk about the command line image viewer sxiv. While it’s a command line tool, of course it spawn a X window to display the pictures. It’s very light and easy of use, it’s my favorite image viewer.

Quick start: (you should read the man page for more informations)

  • sxiv file1 file2… : Sxiv open only files given as parameter or filenames from stdin
  • p/n : previous/next
  • f : fullscreen
  • 12 G : go to 12th image of the list
  • Return : switch to the thumbnails mode / select the image from the thumbnails mode
  • q : quit
  • a lot more in the well written man page !

For power users who have a LOT of pictures to sort: Sxiv has a nice function that let you mark images you see and dump the list of marked images in a file (see parameter -o).

Tip for zsh users, if you want to read every jpg files in a tree, you
can use sxiv **/*.jpg globbing as seen in the Zsh cheat sheet
).

In OpenBSD ports tree, check graphics/sxiv.

Port of the week: bwm-ng

Written by Solène, on 06 May 2016.
Tags: #portoftheweek #networking

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I am starting a periodic posting for something I wanted to do since a long time. Take a port in the tree and introduce it quickly. There are tons of ports in the tree that we don’t know about. So, I will write frequently about ports that I use frequently and that I find useful, if you read this, maybe I will find a new tool to your collection of “useful program”. :-)

For a first one, I would like to present net/bwm-ng. Its name stands for “BandWitch Monitor next-generation”, it allows the user to watch in real-time the bandwith usage of the different network interfaces. By default, it will update the display every 0.5 second. You can change the frequency of updating by pressing keys ‘+’ and ‘-’.

Let see the bindings of the interactive mode :

  • ‘t’ will cycle between current rate, maximum peak, sum, average on 30 seconds.
  • ‘n’ will cycle between data sources, on OpenBSD it defaults to “getifaddrs” and you can also choose “sysctl” or “netstat -i”.
  • ‘d’ will change the unit, by default it shows KB but you can change to another units that suits better your current data.

Summary output after downloading a file

bwm-ng v0.6.1 (probing every 5.700s), press 'h' for help
input: getifaddrs type: sum
-         iface                   Rx                   Tx                Total
==============================================================================
            lo0:           0.00  B              0.00  B              0.00  B
            em0:          19.89 MB            662.82 KB             20.54 MB
         pflog0:           0.00  B              0.00  B              0.00  B
------------------------------------------------------------------------------
          total:          19.89 MB            662.82 KB             20.54 MB

It’s available on *BSD, Linux and maybe others.

In OpenBSD ports tree, look for net/bwm-ng.

My mutt cheat sheet

Written by Solène, on 03 May 2016.
Tags: #cheatsheet #mutt #email

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I am learning mutt and I am lost. If you are like me, you may like the following cheat sheet!

I am using it through imap, it may be different with local mailbox.

Note: case is important

  • Change folder : Y

  • Filter the display with l (for limit) and give a filter using this syntax:

  • ~d <2w: ~d for date and <2w for “less than 2 weeks”

  • ~b "hello mate": ~b is for body and the string is something to find in the body

  • ~f somebody@zxy.abc: ~f for from and you can make an expression

  • ~s "Urgent": ~s for subject and use a pattern

  • ; to apply a tag to marked messages

  • Deleting mails using a filter: press D and write the filter

  • Delete a mail: d (it will be marked as Deleted)

Deleted messages will be removed when you change the folder or if you exit. Press $ to trigger manually.

My zsh cheat sheet

Written by Solène, on 03 May 2016.
Tags: #cheatsheet #zsh

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I may add new things in the future, as they come for me, if I find new features useful.

How to repeat a command n time

repeat 5 curl http://localhost/counter_add.php

How to expand recursively

If you want to find every file ending by .lisp in the folder and subfolder you can use the following syntax. Using ****** inside a pattern while do a recursive globbing.

ls **/*.lisp

Work with temp files

If you want to work on some command outputs without having to manage temporary files, zsh can do it for you with the following syntax: =(command that produces stdout).

In the example we will use emacs to open the list of the files in our personal folder.

emacs =(find ~ -type f)

This syntax will produce a temp file that will be removed when emacs exits.

My ~/.zshrc

here is my ~/.zshrc, very simple (I didn’t pasted the aliases I have), I have a 1000 lines history that skips duplicates.

HISTFILE=~/.histfile
HISTSIZE=1000
SAVEHIST=1000
setopt hist_ignore_all_dups
setopt appendhistory
bindkey -e
zstyle :compinstall filename '/home/solene/.zshrc'
autoload -Uz compinit
compinit
export LANGUAGE=fr_FR.UTF-8
export LANG=fr_FR.UTF-8
export LC_ALL=fr_FR.UTF-8
export LC_CTYPE=fr_FR.UTF-8
export LC_MESSAGES=fr_FR.UTF-8

Simple emacs config

Written by Solène, on 02 May 2016.
Tags: #emacs #cheatsheet

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Here is a dump of my emacs config file. That may be useful for some emacs users who begin.

If you doesn’t want to have your_filename.txt~ files with a tilde at the end (this is a default backup file), add this

; I don't want to have backup files everywhere with filename~ name 
(setq backup-inhibited t) 
(setq auto-save-default nil)

To have parenthesis highlighting on match, which is very useful, you will need this

; show match parenthesis 
(show-paren-mode 1)

I really like this one. It will save the cursor position in every file you edit. When you edit it again, you start exactly where you leaved the last time.

; keep the position of the cursor after editing 
(setq save-place-file "~/.emacs.d/saveplace") 
(setq-default save-place t) 
(require 'saveplace)`

If you write in utf-8 (which is very common now) you should add this.

; utf8 
(prefer-coding-system 'utf-8)

Emacs modes are used depending on the extension of a file. Sometime you need to edit files with a custom extension but you want to use a mode for it. So, you just need to add some line like this to get your mode automatically when you load the file.

; associate extension - mode 
(add-to-list 'auto-mode-alist '("\\.md\\'" . markdown-mode)) 
(add-to-list 'auto-mode-alist '("\\.tpl$" . html-mode))

My Org-mode part in the config file

(require 'org)
(define-key global-map "\C-ca" 'org-agenda)
(setq org-log-done t)
(setq org-agenda-files (list "~/Org/work.org" "~/Org/home.org"))

Stop mixing tabs and space when indenting

(setq indent-tabs-mode nil)

How to add a route through a specific interface on FreeBSD (10 to 13)

Written by Solène, on 02 May 2016.
Tags: #freebsd #networking

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If one day under FreeBSD (from 10 to 13 at least) you have a system with multiple IP addresses on the same network and you need to use a specific IP for a route, you have to use the -ifa parameter in the route command.

In our example, we have to use the address 192.168.1.140 to access the network 192.168.30.0 through the router 192.168.1.1, this is as easy as the following.

route add -net 192.168.30.0 192.168.1.1 -ifa 192.168.1.140

You can add this specific route like any other route in your rc.conf as usual, just add the -ifa X.X.X.X parameter.