Search Results: "alpha"

9 October 2024

Ben Hutchings: FOSS activity in September 2024

9 September 2024

Ben Hutchings: FOSS activity in July 2024

7 September 2024

Sergio Durigan Junior: Chatting in the 21st century

Several people have been asking me to explain and/or write about my solution for chatting nowadays. I realize that the current scenario is much more complex than, say, 10 or 20 years ago. Back then, this post would probably be more about the IRC client I used than about different chatting technologies. I have also spent a non trivial amount of time setting things up the way I want, so I understand that it s about time to write about my setup not only because I think it can be helpful to others, but also because I would like to document things for myself.

The backbone: Matrix I chose to use Matrix as the place where I integrate everything. Despite there being some heavy (and justified) criticism on the protocol itself, it serves me well for what I need right now. Obviously, I don t like the fact that I have to provide Matrix and all of its accompanying bridges a VPS with 4GB of RAM and 3 vCPUs, but I think that that ship has sailed, unfortunately. In an ideal world, I would be using XMPP and dedicating only a fraction of the resources I m using today to have a full chat system. And since I have been running my personal XMPP server for more than a decade now, I did try to find a solution that would allow me to keep using it, but unfortunately the protocol became almost a hobbyist thing, so there s that.

A few disclaimers I self-host everything, including my Matrix server. Much of what I did won t work if you don t self-host Matrix, so keep that in mind. This won t be a post teaching you how to deploy the services. My intention is to describe what I use and for what purpose. Also, as much as I try to use Debian packages for everything I do, I opted to deploy all services using a community-maintained Ansible playbook which is very well written and organized: matrix-docker-ansible-deploy. Last but not least, as I said above, you will likely need a machine with a good amount of RAM, CPU and storage, especially if you deploy Synapse as your Matrix homeserver (which is what I recommend if you plan to use the bridges I ll mention). My current VPS has 4GB of RAM, 3 vCPUs and 80GB of storage (of which I m currently using approximately 55GB).

Problem #1: my Matrix client(s) There are a lot of clients that can talk the Matrix protocol, but most of them are either web clients or GUI programs. I live on the terminal, more specifically inside Emacs, so I settled for the amazing ement.el Emacs mode. It works surprisingly well, but unfortunately doesn t support end-to-end encryption out of the box; for that, you have to hook it up with pantalaimon. Unfortunately, the project seems abandoned and therefore I don t recommend you to use it. I don t use it myself. When I have to reply some E2E encrypted message from another user, I go to my web browser and use my self-hosted Element client. It s a nuisance, but one that I m willing to accept because of security concerns. If you re into web clients and don t want to use Element (because it is heavy), you can try Cinny. It s lightweight and supports a decent set of features. If you re a terminal lover but don t use Emacs, you may want to try gomuks or iamb.

Problem #2: IRC bridging There are basically two types of IRC bridges for Matrix:
  • The regular and most used matrix-appservice-irc. This bridge takes Matrix to IRC (think of IRC users with the [m] suffix appended to their nicknames), and is what the matrix.org and other big homeservers (including matrix.debian.social) use. It s a complex service which allows thousands of Matrix users to connect to IRC networks, but that unfortunately has complex problems and is only worth using if you intend to host a community server.
  • A bouncer-like bridge called Heisenbridge. This is what I use personally. It takes IRC to Matrix, which means that people on IRC will not know that you re using Matrix. This bridge is much simpler, and because it acts like a bouncer it s pretty much impossible for it to cause problems with the IRC network.
Due to the fact that I sometimes like to use other IRC clients, I still run a regular ZNC bouncer, and I use Heisenbridge to connect to my ZNC. This means that I can use, e.g., ERC inside Emacs and my Matrix bridge at the same time. But you don t necessarily need to run another bouncer; you can simply use Heisenbridge and connect directly to the IRC network(s) you want. A word of caution, though: unlike ZNC, Heisenbridge doesn t support per-user configuration when you use it in bouncer mode. This is the reason why you need to self-host it, and why it s not possible to offer the service to other users (they would have access to your IRC network configuration otherwise). It s also worth talking about logs. I find that keeping logs of everything that goes on IRC has saved me a bunch of times, and so I find it really important to continue doing that. Unfortunately, neither ement.el nor Element support logging things out of the box (at least not that I know). This is also one of the reasons why I still keep my ZNC around: I configure it to log everything.

Problem #3: Telegram I don t use Telegram myself, but unfortunately several people from the Debian community do, especially in Brazil. There is a whole Debian community on Telegram, and I wanted to be able to bridge our Debian Matrix channels to their Telegram counterparts. I am currently using mautrix-telegram for that, and it s working great. You need someone with a Telegram account to configure their credentials so that the bridge can connect to it, but afterwards it s really easy to bridge channels together.

Problem #4: GitLab webhooks Something else I wanted to be able to do was to receive notifications regarding new issues, merge requests and other activities from Salsa. For this, I m using maubot, which is awesome and has a huge list of plugins. I m using the gitlab one.

Final thoughts Overall, I m satisfied with the setup I have now. It has certainly taken some time and effort to find the right tool for each problem I needed to solve, and I still feel like there are some rough edges to soften (like the fact that my Emacs client doesn t support E2E encryption out of the box, or the whole logging situation), but otherwise things are working fine and I haven t had any big problems with the deployment. You do have to be much more careful about stuff (for example, when I installed an unrelated service that hijacked my Apache configuration and made Matrix s federation silently stop working), though. If you have more specific questions about any part of my setup, shoot me an email and I ll do my best to help. Happy chatting!

8 August 2024

Jonathan Carter: DebConf24 Busan, South Korea

I m finishing typing up this blog entry hours before my last 13 hour leg back home, after I spent 2 weeks in Busan, South Korea for DebCamp24 and DebCamp24. I had a rough year and decided to take it easy this DebConf. So this is the first DebConf in a long time where I didn t give any talks. I mostly caught up on a bit of packaging, worked on DebConf video stuff, attended a few BoFs and talked to people. Overall it was a very good DebConf, which also turned out to be more productive than I expeced it would. In the welcome session on the first day of DebConf, Nicolas Dandrimont mentioned that a benefit of DebConf is that it provides a sort of caffeine for your Debian motivation. I could certainly feel that affect swell as the days went past, and it s nice to be excited about some ideas again that would otherwise be fading.

Recovering DPL It s a bit of a gear shift being DPL for 4 years, and DebConf Committee for nearly 5 years before that, and then being at DebConf while some issue arise (as it always does during a conference). At first I jump into high alert mode, but then I have to remind myself it s not your problem anymore and let others deal with it. It was nice spending a little in-person time with Andreas Tille, our new DPL, we did some more handover and discussed some current issues. I still have a few dozen emails in my DPL inbox that I need to collate and forward to Andreas, I hope to finish all that up by the end of August. During the Bits from the DPL talk, the usual question came up whether Andreas will consider running for DPL again, to which he just responded in a slide Maybe . I think it s a good idea for a DPL to do at least two terms if it all works out for everyone, since it takes a while to get up to speed on everything. Also, having been DPL for four years, I have a lot to say about it, and I think there s a lot we can fix in the role, or at least discuss it. If I had the bandwidth for it I would have scheduled a BoF for it, but I ll very likely do that for the next DebConf instead!

Video team I set up the standby loop for the video streaming setup. We call it loopy, it s a bunch of OBS scenes that provide announcements, shows sponsors, the schedule and some social content. I wrote about it back in 2020, but it s evolved quite a bit since then, so I m probably due to write another blog post with a bunch of updates on it. I hope to organise a video team sprint in Cape Town in the first half of next year, so I ll summarize everything before then.

It would ve been great if we could have some displays in social areas that could show talks, the loop and other content, but we were just too pressed for time for that. This year s DebConf had a very compressed timeline, and there was just too much that had to be done and that had to be figured out on the last minute. This put quite a lot of strain on the organisers, but I was glad to see how, for the most part, most attendees were very sympathetic to some rough edges (but I digress ). I added more of the OBS machine setup to the videoteam s ansible repository, so as of now it just needs an ansible setup and the OBS data and it s good to go. The loopy data is already in the videoteam git repository, so I could probably just add a git pull and create some symlinks in ansible and then that machine can be installed from 0% to 100% by just installing via debian-installer with our ansible hooks. This DebConf I volunteered quite a bit for actual video roles during the conference, something I didn t have much time for in recent DebConfs, and it s been fun, especially in a session or two where nearly none of the other volunteers showed up. Sometimes chaos is just fun :-)
Baekyongee is the university mascot, who s visible throughout the university. So of course we included this four legged whale creature on the loop too!

Packaging I was hoping to do more packaging during DebCamp, but at least it was a non-zero amount:
  • Uploaded gdisk 1.0.10-2 to unstable (previously tested effects of adding dh-sequence-movetousr) (Closes: #1073679).
  • Worked a bit on bcachefs-tools (updating git to 1.9.4), but has a build failure that I need to look into (we might need a newer bindgen) update: I m probably going to ROM this package soon, it doesn t seem suitable for packaging in Debian.
  • Calamares: Tested a fix for encrypted installs, and uploaded it.
  • Calamares: Uploaded (3.3.8-1) to backports (at the time of writing it s still in backports-NEW).
  • Backport obs-gradient-source for bookworm.
  • Did some initial packaging on Cambalache, I ll upload to unstable once wlroots (0.18) hits unstable.
  • Pixelorama 1.0 I did some initial packaging for Pixelorama back when we did the MiniDebConf Gaming Edition, but it had a few stoppers back then. Version 1.0 seems to fix all of that, but it depends on Godot 4.2 and we re still on the 3 series in Debian, so I ll upload this once Godot 4.2 hits at least experimental. Godot software/games is otherwise quite easy to run, it s basically just source code / data that is installed and then run via godot-runner (godot3-runner package in Debian).

BoFs Python Team BoF Link to the etherpad / pad archive link and video can be found on the talk page: https://debconf24.debconf.org/talks/31-python-bof/ The session ended up being extended to a second part, since all the issues didn t fit into the first session. I was distracted by too many thing during the Python 3.12 transition (to the point where I thought that 3.11 was still new in Debian), so it was very useful listening to the retrospective of that transition. There was a discussion whether Python 3.13 could still make it to testing in time for freeze, and it seems that there is consensus that it can, although, likely with new experimental features like disabling the global interpreter lock and the just in time compiler disabled. I learned for the first time about the dead batteries project, PEP-0594, which removes ancient modules that have mostly been superseded, from the Python standard library. There was some talk about the process for changing team policy, and a policy discussion on whether we should require autopkgtests as a SHOULD or a MUST for migration to testing. As with many things, the devil is in the details and in my opinion you could go either way and achieve a similar result (the original MUST proposal allowed exceptions which imho made it the same as the SHOULD proposal). There s an idea to do some ongoing remote sprints, like having co-ordinated days for bug squashing / working on stuff together. This is a nice idea and probably a good way to energise the team and also to gain some interest from potential newcomers. Louis-Philipe V ronneau was added as a new team admin and there was some discussion on various Sphinx issues and which Lintian tags might be needed for Python 3.13. If you want to know more, you probably have to watch the videos / read the notes :)
    Debian.net BoF Link to the etherpad / pad archive link can be found on the talk page: https://debconf24.debconf.org/talks/37-debiannet-team-bof Debian Developers can set up services on subdomains on debian.net, but a big problem we ve had before was that developers were on their own for hosting those services. This meant that they either hosted it on their DSL/fiber connection at home, paid for the hosting themselves, or hosted it at different services which became an accounting nightmare to claim back the used funds. So, a few of us started the debian.net hosting project (sometimes we just call it debian.net, this is probably a bit of a bug) so that Debian has accounts with cloud providers, and as admins we can create instances there that gets billed directly to Debian. We had an initial rush of services, but requests have slowed down since (not really a bad thing, we don t want lots of spurious requests). Last year we did a census, to check which of the instances were still used, whether they received system updates and to ask whether they are performing backups. It went well and some issues were found along the way, so we ll be doing that again. We also gained two potential volunteers to help run things, which is great. Debian Social BoF Link to the etherpad / pad archive link can be found on the talk page: https://debconf24.debconf.org/talks/34-debiansocial-bof We discussed the services we run, you can view the current state of things at: https://wiki.debian.org/Teams/DebianSocial Pleroma has shown some cracks over the last year or so, and there are some forks that seem promising. At the same time, it might be worth while considering Mastodon too. So we ll do some comparison of features and maintenance and find a way forward. At the time when Pleroma was installed, it was way ahead in terms of moderation features. Pixelfed is doing well and chugging along nicely, we should probably promote it more. Peertube is working well, although we learned that we still don t have all the recent DebConf videos on there. A bunch of other issues should be fixed once we move it to a new machine that we plan to set up. We re removing writefreely and plume. Nice concepts, but it didn t get much traction yet, and no one who signed up for these actually used it, which is fine, some experimentation with services is good and sometimes they prove to be very popular and other times not. The WordPress multisite instance has some mild use, otherwise haven t had any issues. Matrix ended up to be much, much bigger than we thought, both in usage and in its requirements. It s very stateful and remembers discussions for as long as you let it, so it s Postgres database is continuously expanding, this will also be a lot easier to manage once we have this on the new host. Jitsi is also quite popular, but it could probably be on jitsi.debian.net instead (we created this on debian.social during the initial height of COVID-19 where we didn t have the debian.net hosting yet), although in practice it doesn t really matter where it lives. Most of our current challenges will be solved by moving everything to a new big machine that has a few public IPs available for some VMs, so we ll be doing that shortly. Debian Foundation Discussion BoF This was some brainstorming about the future structure of Debian, and what steps might be needed to get there. It s way too big a problem to take on in a BoF, but we made some progress in figuring out some smaller pieces of the larger puzzle. The DPL is going to get in touch with some legal advisors and our trusted organisations so that we can aim to formalise our relationships a bit more by the time it s DebConf again. I also introduced my intention to join the Debian Partners delegation. When I was DPL, I enjoyed talking with external organisations who wanted to help Debian, but helping external organisations help Debian turned out to be too much additional load on the usual DPL roles, so I m pursuing this with the Debian Partners team, more on that some other time. This session wasn t recorded, but if you feel like you missed something, don t worry, all intentions will be communicated and discussed with project members before anything moves forward. There was a strong agreement in the room though that we should push forward on this, and not reach another DebConf where we didn t make progress on formalising Debian s structure more.

    Social Conference Dinner
    Conference Dinner Photo from Santiago
    The conference dinner took place in the university gymnasium. I hope not many people do sports there in the summer, because it got HOT. There was also some interesting observations on the thermodynamics of the attempted cooling solutions, which was amusing. On the plus side, the food was great, the company was good, and the speeches were kept to a minimum, so it was a great conference dinner, even though it was probably cut a bit short due to the heat. Cheese and Wine Cheese and Wine happened on 1 August, which happens to be the date I became a DD at DebConf17 in Montr al seven years before, so this was a nice accidental celebration of my Debiversary :) Since I m running out of time, I ll add some more photos to this post some time after publishing it :P Group Photo As per DebConf tradition, Aigars took the group photo. You can find the high resolution version on Debian s GitLab instance.
    Debian annual conference Debconf 24, Busan, South Korea
    Photography: Aigars Mahinovs aigarius@debian.org
    License: CC-BYv3+ or GPLv2+
    Talking Ah yes, talking to people is a big part of DebConf, but I didn t keep track of it very well.
    • I mostly listened to Alper a bit about his ideas for his talk about debian installer.
    • I talked to Rhonda a bit about ActivityPub and MQTT and whether they could be useful for publicising Debian activity.
    • Listened to Gunnar and Julian have a discussion about GPG and APT which was interesting.
    • I learned that you can learn Hangul, the Korean alphabet, in about an hour or so (I wish I knew that in all my years of playing StarCraft II).
    • We had the usual continuous keysigning party. Besides it s intended function, this is always a good ice breaker and a way to for shy people to meet other shy people.
    • and many other fly-by discussions.

    Stuff that didn t happen this DebConf
    • loo.py A simple Python script that could eventually replace the obs-advanced-scene-switcher sequencer in OBS. It would also be extremely useful if we d ever replace OBS for loopy. I was hoping to have some time to hack on this, and try to recreate the current loopy in loo.py, but didn t have the time.
    • toetally This year videoteam had to scramble to get a bunch of resistors to assemble some tally light. Even when assembled, they were a bit troublesome. It would ve been nice to hack on toetally and get something ready for testing, but it mostly relies on having something like a rasbperry pi zero with an attached screen in order to work on further. I ll try to have something ready for the next mini conf though.
    • extrepo on debian live I think we should have extrepo installed by default on desktop systems, I meant to start a discussion on this, but perhaps it s just time I go ahead and do it and announce it.
    • Live stream to peertube server It would ve been nice to live stream DebConf to PeerTube, but the dependency tree to get this going got a bit too huge. Following our plans discussed in the Debian Social BoF, we should have this safely ready before the next MiniDebConf and should be able to test it there.
    • Desktop Egg there was this idea to get a stand-in theme for Debian testing/unstable until the artwork for the next release is finalized (Debian bug: #1038660), I have an idea that I meant to implement months ago, but too many things got in the way. It s based on Juliette Taka s Homeworld theme, and basically transforms the homeworld into an egg. Get it? Something that hasn t hatched yet? I also only recently noticed that we never used the actual homeworld graphics (featuring the world image) in the final bullseye release. lol.
    So, another DebConf and another new plush animal. Last but not least, thanks to PKNU for being such a generous and fantastic host to us! See you again at DebConf25 in Brest, France next year!

      4 August 2024

      Matthias Klumpp: Freedesktop Specs Website Update

      The Freedesktop.org Specifications directory contains a list of common specifications that have accumulated over the decades and define how common desktop environment functionality works. The specifications are designed to increase interoperability between desktops. Common specifications make the life of both desktop-environment developers and especially application developers (who will almost always want to maximize the amount of Linux DEs their app can run on and behave as expected, to increase their apps target audience) a lot easier. Unfortunately, building the HTML specifications and maintaining the directory of available specs has become a bit of a difficult chore, as the pipeline for building the site has become fairly old and unmaintained (parts of it still depended on Python 2). In order to make my life of maintaining this part of Freedesktop easier, I aimed to carefully modernize the website. I do have bigger plans to maybe eventually restructure the site to make it easier to navigate and not just a plain alphabetical list of specifications, and to integrate it with the Wiki, but in the interest of backwards compatibility and to get anything done in time (rather than taking on a mega-project that can t be finished), I decided to just do the minimum modernization first to get a viable website, and do the rest later. So, long story short: Most Freedesktop specs are written in DocBook XML. Some were plain HTML documents, some were DocBook SGML, a few were plaintext files. To make things easier to maintain, almost every specification is written in DocBook now. This also simplifies the review process and we may be able to switch to something else like AsciiDoc later if we want to. Of course, one could have switched to something else than DocBook, but that would have been a much bigger chore with a lot more broken links, and I did not want this to become an even bigger project than it already was and keep its scope somewhat narrow. DocBook is a markup language for documentation which has been around for a very long time, and therefore has older tooling around it. But fortunately our friends at openSUSE created DAPS (DocBook Authoring and Publishing Suite) as a modern way to render DocBook documents to HTML and other file formats. DAPS is now used to generate all Freedesktop specifications on our website. The website index and the specification revisions are also now defined in structured TOML files, to make them easier to read and to extend. A bunch of specifications that had been missing from the original website are also added to the index and rendered on the website now. Originally, I wanted to put the website live in a temporary location and solicit feedback, especially since some links have changed and not everything may have redirects. However, due to how GitLab Pages worked (and due to me not knowing GitLab CI well enough ) the changes went live before their MR was actually merged. Rather than reverting the change, I decided to keep it (as the old website did not build properly anymore) and to see if anything breaks. So far, no dead links or bad side effects have been observed, but: If you notice any broken link to specifications.fd.o or anything else weird, please file a bug so that we can fix it! Thank you, and I hope you enjoy reading the specifications in better rendering and more coherent look!

      30 January 2024

      Matthew Palmer: Why Certificate Lifecycle Automation Matters

      If you ve perused the ActivityPub feed of certificates whose keys are known to be compromised, and clicked on the Show More button to see the name of the certificate issuer, you may have noticed that some issuers seem to come up again and again. This might make sense after all, if a CA is issuing a large volume of certificates, they ll be seen more often in a list of compromised certificates. In an attempt to see if there is anything that we can learn from this data, though, I did a bit of digging, and came up with some illuminating results.

      The Procedure I started off by finding all the unexpired certificates logged in Certificate Transparency (CT) logs that have a key that is in the pwnedkeys database as having been publicly disclosed. From this list of certificates, I removed duplicates by matching up issuer/serial number tuples, and then reduced the set by counting the number of unique certificates by their issuer. This gave me a list of the issuers of these certificates, which looks a bit like this:
      /C=BE/O=GlobalSign nv-sa/CN=AlphaSSL CA - SHA256 - G4
      /C=GB/ST=Greater Manchester/L=Salford/O=Sectigo Limited/CN=Sectigo RSA Domain Validation Secure Server CA
      /C=GB/ST=Greater Manchester/L=Salford/O=Sectigo Limited/CN=Sectigo RSA Organization Validation Secure Server CA
      /C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./OU=http://certs.godaddy.com/repository//CN=Go Daddy Secure Certificate Authority - G2
      /C=US/ST=Arizona/L=Scottsdale/O=Starfield Technologies, Inc./OU=http://certs.starfieldtech.com/repository//CN=Starfield Secure Certificate Authority - G2
      /C=AT/O=ZeroSSL/CN=ZeroSSL RSA Domain Secure Site CA
      /C=BE/O=GlobalSign nv-sa/CN=GlobalSign GCC R3 DV TLS CA 2020
      
      Rather than try to work with raw issuers (because, as Andrew Ayer says, The SSL Certificate Issuer Field is a Lie), I mapped these issuers to the organisations that manage them, and summed the counts for those grouped issuers together.

      The Data
      Lieutenant Commander Data from Star Trek: The Next Generation Insert obligatory "not THAT data" comment here
      The end result of this work is the following table, sorted by the count of certificates which have been compromised by exposing their private key:
      IssuerCompromised Count
      Sectigo170
      ISRG (Let's Encrypt)161
      GoDaddy141
      DigiCert81
      GlobalSign46
      Entrust3
      SSL.com1
      If you re familiar with the CA ecosystem, you ll probably recognise that the organisations with large numbers of compromised certificates are also those who issue a lot of certificates. So far, nothing particularly surprising, then. Let s look more closely at the relationships, though, to see if we can get more useful insights.

      Volume Control Using the issuance volume report from crt.sh, we can compare issuance volumes to compromise counts, to come up with a compromise rate . I m using the Unexpired Precertificates colume from the issuance volume report, as I feel that s the number that best matches the certificate population I m examining to find compromised certificates. To maintain parity with the previous table, this one is still sorted by the count of certificates that have been compromised.
      IssuerIssuance VolumeCompromised CountCompromise Rate
      Sectigo88,323,0681701 in 519,547
      ISRG (Let's Encrypt)315,476,4021611 in 1,959,480
      GoDaddy56,121,4291411 in 398,024
      DigiCert144,713,475811 in 1,786,586
      GlobalSign1,438,485461 in 31,271
      Entrust23,16631 in 7,722
      SSL.com171,81611 in 171,816
      If we now sort this table by compromise rate, we can see which organisations have the most (and least) leakiness going on from their customers:
      IssuerIssuance VolumeCompromised CountCompromise Rate
      Entrust23,16631 in 7,722
      GlobalSign1,438,485461 in 31,271
      SSL.com171,81611 in 171,816
      GoDaddy56,121,4291411 in 398,024
      Sectigo88,323,0681701 in 519,547
      DigiCert144,713,475811 in 1,786,586
      ISRG (Let's Encrypt)315,476,4021611 in 1,959,480
      By grouping by order-of-magnitude in the compromise rate, we can identify three bands :
      • The Super Leakers: Customers of Entrust and GlobalSign seem to love to lose control of their private keys. For Entrust, at least, though, the small volumes involved make the numbers somewhat untrustworthy. The three compromised certificates could very well belong to just one customer, for instance. I m not aware of anything that GlobalSign does that would make them such an outlier, either, so I m inclined to think they just got unlucky with one or two customers, but as CAs don t include customer IDs in the certificates they issue, it s not possible to say whether that s the actual cause or not.
      • The Regular Leakers: Customers of SSL.com, GoDaddy, and Sectigo all have compromise rates in the 1-in-hundreds-of-thousands range. Again, the low volumes of SSL.com make the numbers somewhat unreliable, but the other two organisations in this group have large enough numbers that we can rely on that data fairly well, I think.
      • The Low Leakers: Customers of DigiCert and Let s Encrypt are at least three times less likely than customers of the regular leakers to lose control of their private keys. Good for them!
      Now we have some useful insights we can think about.

      Why Is It So?
      Professor Julius Sumner Miller If you don't know who Professor Julius Sumner Miller is, I highly recommend finding out
      All of the organisations on the list, with the exception of Let s Encrypt, are what one might term traditional CAs. To a first approximation, it s reasonable to assume that the vast majority of the customers of these traditional CAs probably manage their certificates the same way they have for the past two decades or more. That is, they generate a key and CSR, upload the CSR to the CA to get a certificate, then copy the cert and key somewhere. Since humans are handling the keys, there s a higher risk of the humans using either risky practices, or making a mistake, and exposing the private key to the world. Let s Encrypt, on the other hand, issues all of its certificates using the ACME (Automatic Certificate Management Environment) protocol, and all of the Let s Encrypt documentation encourages the use of software tools to generate keys, issue certificates, and install them for use. Given that Let s Encrypt has 161 compromised certificates currently in the wild, it s clear that the automation in use is far from perfect, but the significantly lower compromise rate suggests to me that lifecycle automation at least reduces the rate of key compromise, even though it doesn t eliminate it completely.

      Explaining the Outlier The difference in presumed issuance practices would seem to explain the significant difference in compromise rates between Let s Encrypt and the other organisations, if it weren t for one outlier. This is a largely traditional CA, with the manual-handling issues that implies, but with a compromise rate close to that of Let s Encrypt. We are, of course, talking about DigiCert. The thing about DigiCert, that doesn t show up in the raw numbers from crt.sh, is that DigiCert manages the issuance of certificates for several of the biggest hosted TLS providers, such as CloudFlare and AWS. When these services obtain a certificate from DigiCert on their customer s behalf, the private key is kept locked away, and no human can (we hope) get access to the private key. This is supported by the fact that no certificates identifiably issued to either CloudFlare or AWS appear in the set of certificates with compromised keys. When we ask for all certificates issued by DigiCert , we get both the certificates issued to these big providers, which are very good at keeping their keys under control, as well as the certificates issued to everyone else, whose key handling practices may not be quite so stringent. It s possible, though not trivial, to account for certificates issued to these hosted TLS providers, because the certificates they use are issued from intermediates branded to those companies. With the crt.sh psql interface we can run this query to get the total number of unexpired precertificates issued to these managed services:
      SELECT SUM(sub.NUM_ISSUED[2] - sub.NUM_EXPIRED[2])
        FROM (
          SELECT ca.name, max(coalesce(coalesce(nullif(trim(cc.SUBORDINATE_CA_OWNER), ''), nullif(trim(cc.CA_OWNER), '')), cc.INCLUDED_CERTIFICATE_OWNER)) as OWNER,
                 ca.NUM_ISSUED, ca.NUM_EXPIRED
            FROM ccadb_certificate cc, ca_certificate cac, ca
           WHERE cc.CERTIFICATE_ID = cac.CERTIFICATE_ID
             AND cac.CA_ID = ca.ID
        GROUP BY ca.ID
        ) sub
       WHERE sub.name ILIKE '%Amazon%' OR sub.name ILIKE '%CloudFlare%' AND sub.owner = 'DigiCert';
      
      The number I get from running that query is 104,316,112, which should be subtracted from DigiCert s total issuance figures to get a more accurate view of what DigiCert s regular customers do with their private keys. When I do this, the compromise rates table, sorted by the compromise rate, looks like this:
      IssuerIssuance VolumeCompromised CountCompromise Rate
      Entrust23,16631 in 7,722
      GlobalSign1,438,485461 in 31,271
      SSL.com171,81611 in 171,816
      GoDaddy56,121,4291411 in 398,024
      "Regular" DigiCert40,397,363811 in 498,732
      Sectigo88,323,0681701 in 519,547
      All DigiCert144,713,475811 in 1,786,586
      ISRG (Let's Encrypt)315,476,4021611 in 1,959,480
      In short, it appears that DigiCert s regular customers are just as likely as GoDaddy or Sectigo customers to expose their private keys.

      What Does It All Mean? The takeaway from all this is fairly straightforward, and not overly surprising, I believe.

      The less humans have to do with certificate issuance, the less likely they are to compromise that certificate by exposing the private key. While it may not be surprising, it is nice to have some empirical evidence to back up the common wisdom. Fully-managed TLS providers, such as CloudFlare, AWS Certificate Manager, and whatever Azure s thing is called, is the platonic ideal of this principle: never give humans any opportunity to expose a private key. I m not saying you should use one of these providers, but the security approach they have adopted appears to be the optimal one, and should be emulated universally. The ACME protocol is the next best, in that there are a variety of standardised tools widely available that allow humans to take themselves out of the loop, but it s still possible for humans to handle (and mistakenly expose) key material if they try hard enough. Legacy issuance methods, which either cannot be automated, or require custom, per-provider automation to be developed, appear to be at least four times less helpful to the goal of avoiding compromise of the private key associated with a certificate.

      Humans Are, Of Course, The Problem
      Bender, the robot from Futurama, asking if we'd like to kill all humans No thanks, Bender, I'm busy tonight
      This observation that if you don t let humans near keys, they don t get leaked is further supported by considering the biggest issuers by volume who have not issued any certificates whose keys have been compromised: Google Trust Services (fourth largest issuer overall, with 57,084,529 unexpired precertificates), and Microsoft Corporation (sixth largest issuer overall, with 22,852,468 unexpired precertificates). It appears that somewhere between most and basically all of the certificates these organisations issue are to customers of their public clouds, and my understanding is that the keys for these certificates are managed in same manner as CloudFlare and AWS the keys are locked away where humans can t get to them. It should, of course, go without saying that if a human can never have access to a private key, it makes it rather difficult for a human to expose it. More broadly, if you are building something that handles sensitive or secret data, the more you can do to keep humans out of the loop, the better everything will be.

      Your Support is Appreciated If you d like to see more analysis of how key compromise happens, and the lessons we can learn from examining billions of certificates, please show your support by buying me a refreshing beverage. Trawling CT logs is thirsty work.

      Appendix: Methodology Limitations In the interests of clarity, I feel it s important to describe ways in which my research might be flawed. Here are the things I know of that may have impacted the accuracy, that I couldn t feasibly account for.
      • Time Periods: Because time never stops, there is likely to be some slight mismatches in the numbers obtained from the various data sources, because they weren t collected at exactly the same moment.
      • Issuer-to-Organisation Mapping: It s possible that the way I mapped issuers to organisations doesn t match exactly with how crt.sh does it, meaning that counts might be skewed. I tried to minimise that by using the same data sources (the CCADB AllCertificates report) that I believe that crt.sh uses for its mapping, but I cannot be certain of a perfect match.
      • Unwarranted Grouping: I ve drawn some conclusions about the practices of the various organisations based on their general approach to certificate issuance. If a particular subordinate CA that I ve grouped into the parent organisation is managed in some unusual way, that might cause my conclusions to be erroneous. I was able to fairly easily separate out CloudFlare, AWS, and Azure, but there are almost certainly others that I didn t spot, because hoo boy there are a lot of intermediate CAs out there.

      17 November 2023

      Reproducible Builds (diffoscope): diffoscope 252 released

      The diffoscope maintainers are pleased to announce the release of diffoscope version 252. This version includes the following changes:
      * As UI/UX improvement, try and avoid printing an extended traceback if
        diffoscope runs out of memory. This may not always be possible to detect.
      * Mark diffoscope as stable in setup.py (for PyPI.org). Whatever diffoscope
        is, at least, not "alpha" anymore.
      
      You find out more by visiting the project homepage.

      22 October 2023

      Ravi Dwivedi: Software Freedom Day at sflc.in

      Software Freedom Law Center, India, also known as sflc.in, organized an event to celebrate the Software Freedom Day on 30th September 2023. Me, Sahil, Contrapunctus and Suresh joined. The venue was at the SFLC India office in Delhi. The sflc.in office was on the second floor of what looked like someone s apartment:). I also met Chirag, Orendra, Surbhi and others. My plan was to have a stall on LibreOffice and Prav app to raise awareness about these projects. I didn t have QR code for downloading prav app printed already, so I asked the people at sflc.in if they can get it printed for me. They were very kind and helped me in getting a color printout for me. So, I got a stall in their main room. Surbhi was having an Inkscape stall next to mine and gave me company. People came and asked about the prav project and then I realized I was still too tired to explain the idea behind the prav project and about LibreOffice (after a long Kerala trip). We got a few prav app installs during the event, which is cool.
      My stall. Photo credits: Tejaswini.
      Sahil had Debian stall and contrapunctus had OpenStreetMap stall. After about an hour, Revolution OS was screened for all of us to watch, along with popcorn. The documentary gave an overview of history of Free Software Movement. The office had a kitchen where fresh chai was being made and served to us. The organizers ordered a lot of good snacks for us.
      Snacks and tea at the front desk. CC-BY-SA 4.0 by Ravi Dwivedi.
      I came out of the movie hall to take more tea and snacks from the front desk. I saw a beautiful painting was hanging at the wall opposite to the front desk and Tejaswini (from sflc.in) revealed that she had made it. The tea was really good as it was freshly made in the kitchen. After the movie, we played a game of pictionary. We were divided into two teams. The game goes as follows: A person from a team is selected and given a term related to freedom respecting software written on a piece of paper, but concealed from other participants. Then that person draws something on the board (no logo, no alphabets) without speaking. If the team from which the person belongs correctly guesses the term, the team gets one step ahead on the leader board. The team who reaches the finish line wins. I recall some fun pictionaries. Like, the one in the picture below seems far from the word Wireguard and even then someone from the team guessed that word. Our team won in the end \o/.
      Pictionary drawing nowhere close to the intended word Wireguard :), which was guessed. Photo by Ravi Dwivedi, CC-BY-SA 4.0.
      Then, we posed for a group picture. At the end, SFLC.in had a delicious cake in store for us. They had some merchandise - handbags, T-shirts, etc. which we could take if we donate some amount to SFLC.in. I bought a handbag with Ban Plastic, not Internet written on it in exchange for donation. I hope that gives people around me a powerful message :) .
      Group photo. Photo credits: Tejaswini.
      Tasty cake. CC-BY-SA 4.0 by Ravi Dwivedi.
      Merchandise by sflc.in. CC-BY-SA 4.0 by Ravi Dwivedi.
      All in all, a nice event by sflc.in :)

      27 September 2023

      Antoine Beaupr : How big is Debian?

      Now this was quite a tease! For those who haven't seen it, I encourage you to check it out, it has a nice photo of a Debian t-shirt I did not know about, to quote the Fine Article:
      Today, when going through a box of old T-shirts, I found the shirt I was looking for to bring to the occasion: [...] For the benefit of people who read this using a non-image-displaying browser or RSS client, they are respectively:
         10 years
        100 countries
       1000 maintainers
      10000 packages
      
      and
              1 project
             10 architectures
            100 countries
           1000 maintainers
          10000 packages
         100000 bugs fixed
        1000000 installations
       10000000 users
      100000000 lines of code
      
      20 years ago we celebrated eating grilled meat at J0rd1 s house. This year, we had vegan tostadas in the menu. And maybe we are no longer that young, but we are still very proud and happy of our project! Now How would numbers line up today for Debian, 20 years later? Have we managed to get the bugs fixed line increase by a factor of 10? Quite probably, the lines of code we also have, and I can only guess the number of users and installations, which was already just a wild guess back then, might have multiplied by over 10, at least if we count indirect users and installs as well
      Now I don't know about you, but I really expected someone to come up with an answer to this, directly on Debian Planet! I have patiently waited for such an answer but enough is enough, I'm a Debian member, surely I can cull all of this together. So, low and behold, here are the actual numbers from 2023! So it doesn't line up as nicely, but it looks something like this:
               1 project
              10 architectures
              30 years
             100 countries (actually 63, but we'd like to have yours!)
            1000 maintainers (yep, still there!)
           35000 packages
          211000 *binary* packages
         1000000 bugs fixed
      1000000000 lines of code
       uncounted installations and users, we don't track you
      
      So maybe the the more accurate, rounding to the nearest logarithm, would look something like:
               1 project
              10 architectures
             100 countries (actually 63, but we'd like to have yours!)
            1000 maintainers (yep, still there!)
          100000 packages
         1000000 bugs fixed
      1000000000 lines of code
       uncounted installations and users, we don't track you
      
      I really like how the "packages" and "bugs fixed" still have an order of magnitude between them there, but that the "bugs fixed" vs "lines of code" have an extra order of magnitude, that is we have fixed ten times less bugs per line of code since we last did this count, 20 years ago. Also, I am tempted to put 100 years in there, but that would be rounding up too much. Let's give it another 30 years first. Hopefully, some real scientist is going to balk at this crude methodology and come up with some more interesting numbers for the next t-shirt. Otherwise I'm available for bar mitzvahs and children parties.

      26 September 2023

      Ravi Dwivedi: Fixing keymaps in Chromebook Running Debian Bookworm

      I recently bought an HP Chromebook from Abhas who had already flashed coreboot in it. I ran a fresh installation of Debian 12 (Bookworm) on it with KDE Plasma. Right after installation, the Wi-Fi and bluetooth were working, but I was facing two issues: So I asked my friend Alper for help on fixing the same as he has some experience with Chromebooks. Thanks a lot Alper for the help. I am documenting our steps here for helping others who are facing this issue. Note: This works in X11. For wayland, the steps might differ. To set system-wide keyboard configuration on Debian systems:
      $ sudo dpkg-reconfigure keyboard-configuration
      
      Choose Chromebook as the Keyboard Model . Each DE should default to the system configuration, but might need its own configuration which would similarly be available in their GUI tools. But you can check and set it manually from the command line, for example as in this thread. To check the keyboard model Xorg-based DEs:
      $ setxkbmap -print -query   grep model:
      model:  pc104
      
      To change it temporarily, until a reboot:
      $ setxkbmap -model chromebook
      
      If it s not there in KDE settings that would be a bug, To change it persistently for KDE:
      $ cat >>.config/kxkbrc <<EOF
      [Layout]
      Model=chromebook
      EOF
      
      This thread was helpful.

      Ravi Dwivedi: Fixing audio and keymaps in Chromebook Running Debian Bookworm

      I recently bought an HP Chromebook from Abhas who had already flashed coreboot in it. I ran a fresh installation of Debian 12 (Bookworm) on it with KDE Plasma. Right after installation, the Wi-Fi and bluetooth were working, but I was facing two issues:

      Fixing audio I ran the script mentioned here and that fixed the audio. The instructions from that link are:
      git clone https://github.com/WeirdTreeThing/chromebook-linux-audio
      cd chromebook-linux-audio
      ./setup-audio
      

      Fixing keyboard I asked my friend Alper for help on fixing the keyboard as he has some experience with Chromebooks. Thanks a lot Alper for the help. I am documenting our steps here for helping others who are facing this issue. Note: This works in X11. For wayland, the steps might differ. To set system-wide keyboard configuration on Debian systems:
      $ sudo dpkg-reconfigure keyboard-configuration
      
      Choose Chromebook as the Keyboard Model . Each DE should default to the system configuration, but might need its own configuration which would similarly be available in their GUI tools. But you can check and set it manually from the command line, for example as in this thread. To check the keyboard model Xorg-based DEs:
      $ setxkbmap -print -query   grep model:
      model:  pc104
      
      To change it temporarily, until a reboot:
      $ setxkbmap -model chromebook
      
      If it s not there in KDE settings that would be a bug, To change it persistently for KDE:
      $ cat >>.config/kxkbrc <<EOF
      [Layout]
      Model=chromebook
      EOF
      
      This thread was helpful.

      24 September 2023

      Thomas Goirand: Searching for a Ryzen 9, 16 cores, small laptop

      The new 7945HX CPU from AMD is currently the most powerful. I d love to have one of them, to replace the now aging 6 core Xeon that I ve been using for more than 5 years. So, I ve been searching for a laptop with that CPU. Absolutely all of the laptops I found with this CPU also embed a very powerful RTX 40 0 series GPU, that I have no use: I don t play games, and I don t do AI. I just want something that builds Debian packages fast (like Ceph, that takes more than 1h to build for me ). The more cores I get, the faster all OpenStack unit tests are running too (stestr does a moderately good job at spreading the tests to all cores). That d be ok if I had to pay more for a GPU that I don t need, and I would have deal with the annoyance of the NVidia driver, if only I could find something with a correct size. But I can only find 16 or bigger laptops, that wont fit in my scooter back case (most of the time, these laptops have an 17 inch screen: that s a way too big). Currently, I found: If one of the readers of this post find a smaller laptop with a 7945HX CPU, please let me know! Even better if I can get rid of the expensive NVidia GPU.

      26 August 2023

      Christoph Berg: PostgreSQL Popularity Contest

      Back in 2015, when PostgreSQL 9.5 alpha 1 was released, I had posted the PostgreSQL data from Debian's popularity contest. 8 years and 8 PostgreSQL releases later, the graph now looks like this: Currently, the most popular PostgreSQL on Debian systems is still PostgreSQL 13 (shipped in Bullseye), followed by PostgreSQL 11 (Buster). At the time of writing, PostgreSQL 9.6 (Stretch) and PostgreSQL 15 (Bookworm) share the third place, with 15 rising quickly.

      25 August 2023

      Ian Jackson: I cycled to all the villages in alphabetical order

      This last weekend I completed a bike rides project I started during the first Covid lockdown in 2020: I ve cycled to every settlement (and radio observatory) within 20km of my house, in alphabetical order. Stir crazy In early 2020, during the first lockdown, I was going a bit stir crazy. Clare said you re going very strange, you have to go out and get some exercise . After a bit of discussion, we came up with this plan: I d visit all the local villages, in alphabetical order. Choosing the radius I decided that I would pick a round number of kilometers, as the crow flies, from my house. 20km seemed about right. 25km would have included Ely, which would have been nice, but it would have added a great many places, all of them quite distant. Software I wrote a short Rust program to process OSM data into a list of places to visit, and their distances and bearings. You can download a tarball of the alphabetical villages scanner. (I haven t published the git history because it has my house s GPS coordinates in it, and because I committed the output files from which that location can be derived.) The Rides I set off on my first ride, to Aldreth, on Sunday the 31st of May 2020. The final ride collected Yelling, on Saturday the 19th of August 2023. I did quite a few rides in June and July 2020 - more than one a week. (I d read the lockdown rules, and although some of the government messaging said you should stay near your house, that wasn t in the legislation. Of course I didn t go into any buildings or anything.) I m not much of a morning person, so I often set off after lunch. For the longer rides I would usually pack a picnic. Almost all of the rides I did just by myself. There were a handful where I had friends along: Dry Drayton, which I collected with Clare, at night. I held my bike up so the light shone at the village sign, so we could take a photo of it. Madingley, Melbourn and Meldreth, which was quite an expedition with my friend Ben. We went out as far as Royston and nearby Barley (both outside my radius and not on my list) mostly just so that my project would have visited Hertfordshire. The Hemingfords, where I had my friend Matthew along, and we had a very nice pub lunch. Girton and Wilburton, where I visited friends. Indeed, I stopped off in Wilburton on one or two other occasions. And, of course, Yelling, for which there were four of us, again with a nice lunch (in Eltisley). I had relatively little mechanical trouble. My worst ride for this was Exning: I got three punctures that day. Luckily the last one was close to home. I often would stop to take lots of photos en-route. My mum in particular appreciated all the pretty pictures. Rules I decided on these rules: I would cycle to each destination, in order, and it would count as collected if I rode both there and back. I allowed collecting multiple villages in the same outing, provided I did them in the right order. (And obviously I was allowed to pass through places out of order, without counting them.) I tried to get a picture of the village sign, where there was one. Failing that, I got a picture of something in the village with the village s name on it. I think the only one I didn t manage this for was Westley Bottom; I had to make do with the word Westley on some railway level crossing equipment. In Barway I had to make do with a planning application, stuck to a pole. I tried not to enter and leave a village by the same road, if possible. Edge cases I had to make some decisions: I decided that I would consider the project complete if I visited everywhere whose centre was within my radius. But the centre of a settlement is rather hard to define. I needed a hard criterion for my OpenStreetMap data mining: a place counted if there was any node, way or relation, with the relevant place tag, any part of which was within my ambit. That included some places that probably oughtn t to have counted, but, fine. I also decided that I wouldn t visit suburbs of Cambridge, separately from Cambridge itself. I don t consider them separate settlements, at least, not if they re conurbated with Cambridge. So that excluded Trumpington, for example. But I decided that Girton and Fen Ditton were (just) separable. Although the place where I consider Girton and Cambridge to nearly touch, is administratively well inside Girton, I chose to look at land use (on the ground, and in OSM data), rather than administrative boundaries. But I did visit both Histon and Impington, and all each of the Shelfords and Stapleford, as separate entries in my list. Mostly because otherwise I d have to decide whether to skip (say) Impington, or Histon. Whereas skipping suburbs of Cambridge in favour of Cambridge itself was an easy decision, and it also got rid of a bunch of what would have been quite short, boring, urban expeditions. I sorted all the Greats and Littles under G and L, rather than (say) Shelford, Great , which seemed like it would be cheating because then I would be able to do Shelford, Great and Shelford, Little in one go. Northstowe turned from mostly a building site into something that was arguably a settlement, during my project. It wasn t included in the output of my original data mining. Of course it s conurbated with Oakington - but happily, Northstowe inserts right before Oakington in the alphabetical list, so I decided to add it, visiting both the old and new in the same day. There are a bunch of other minor edge cases. Some villages have an outlying hamlet. Mostly I included these. There are some individual farms, which I generally didn t count. Some stats I visited 150 villages plus the Lords Bridge radio observatory. The project took 3 years and 3 months to complete. There were 96 rides, totalling about 4900km. So my mean distance was around 51km. The median distance per ride was a little higher, at around 52 km, and the median duration (including stoppages) was about 2h40. The total duration, if you add them all up, including stoppages, was about 275h, giving a mean speed including photo stops, lunches and all, of 18kph. The longest ride was 89.8km, collecting Scotland Farm, Shepreth, and Six Mile Bottom, so riding across the Cam valley. The shortest ride was 7.9km, collecting Cambridge (obviously); and I think that s the only one I did on my Brompton. The rest were all on my trusty Thorn Audax. My fastest ride (ranking by distance divided by time spent in motion) was to collect Haddenham, where I covered 46.3km in 1h39, giving an average speed in motion of 28.0kph. The most I collected in one day was 5 places: West Wickham, West Wratting, Westley Bottom, Westley Waterless, and Weston Colville. That was the day of the Wests. (There s only one East: East Hatley.) Map Here is a pretty picture of all of my tracklogs:
      Edited 2023-08-25 01:32 BST to correct a slip.


      comment count unavailable comments

      12 July 2023

      Reproducible Builds: Reproducible Builds in June 2023

      Welcome to the June 2023 report from the Reproducible Builds project In our reports, we outline the most important things that we have been up to over the past month. As always, if you are interested in contributing to the project, please visit our Contribute page on our website.


      We are very happy to announce the upcoming Reproducible Builds Summit which set to take place from October 31st November 2nd 2023, in the vibrant city of Hamburg, Germany. Our summits are a unique gathering that brings together attendees from diverse projects, united by a shared vision of advancing the Reproducible Builds effort. During this enriching event, participants will have the opportunity to engage in discussions, establish connections and exchange ideas to drive progress in this vital field. Our aim is to create an inclusive space that fosters collaboration, innovation and problem-solving. We are thrilled to host the seventh edition of this exciting event, following the success of previous summits in various iconic locations around the world, including Venice, Marrakesh, Paris, Berlin and Athens. If you re interesting in joining us this year, please make sure to read the event page] which has more details about the event and location. (You may also be interested in attending PackagingCon 2023 held a few days before in Berlin.)
      This month, Vagrant Cascadian will present at FOSSY 2023 on the topic of Breaking the Chains of Trusting Trust:
      Corrupted build environments can deliver compromised cryptographically signed binaries. Several exploits in critical supply chains have been demonstrated in recent years, proving that this is not just theoretical. The most well secured build environments are still single points of failure when they fail. [ ] This talk will focus on the state of the art from several angles in related Free and Open Source Software projects, what works, current challenges and future plans for building trustworthy toolchains you do not need to trust.
      Hosted by the Software Freedom Conservancy and taking place in Portland, Oregon, FOSSY aims to be a community-focused event: Whether you are a long time contributing member of a free software project, a recent graduate of a coding bootcamp or university, or just have an interest in the possibilities that free and open source software bring, FOSSY will have something for you . More information on the event is available on the FOSSY 2023 website, including the full programme schedule.
      Marcel Fourn , Dominik Wermke, William Enck, Sascha Fahl and Yasemin Acar recently published an academic paper in the 44th IEEE Symposium on Security and Privacy titled It s like flossing your teeth: On the Importance and Challenges of Reproducible Builds for Software Supply Chain Security . The abstract reads as follows:
      The 2020 Solarwinds attack was a tipping point that caused a heightened awareness about the security of the software supply chain and in particular the large amount of trust placed in build systems. Reproducible Builds (R-Bs) provide a strong foundation to build defenses for arbitrary attacks against build systems by ensuring that given the same source code, build environment, and build instructions, bitwise-identical artifacts are created.
      However, in contrast to other papers that touch on some theoretical aspect of reproducible builds, the authors paper takes a different approach. Starting with the observation that much of the software industry believes R-Bs are too far out of reach for most projects and conjoining that with a goal of to help identify a path for R-Bs to become a commonplace property , the paper has a different methodology:
      We conducted a series of 24 semi-structured expert interviews with participants from the Reproducible-Builds.org project, and iterated on our questions with the reproducible builds community. We identified a range of motivations that can encourage open source developers to strive for R-Bs, including indicators of quality, security benefits, and more efficient caching of artifacts. We identify experiences that help and hinder adoption, which heavily include communication with upstream projects. We conclude with recommendations on how to better integrate R-Bs with the efforts of the open source and free software community.
      A PDF of the paper is now available, as is an entry on the CISPA Helmholtz Center for Information Security website and an entry under the TeamUSEC Human-Centered Security research group.
      On our mailing list this month:
      The antagonist is David Schwartz, who correctly says There are dozens of complex reasons why what seems to be the same sequence of operations might produce different end results, but goes on to say I totally disagree with your general viewpoint that compilers must provide for reproducability [sic]. Dwight Tovey and I (Larry Doolittle) argue for reproducible builds. I assert Any program especially a mission-critical program like a compiler that cannot reproduce a result at will is broken. Also it s commonplace to take a binary from the net, and check to see if it was trojaned by attempting to recreate it from source.

      Lastly, there were a few changes to our website this month too, including Bernhard M. Wiedemann adding a simplified Rust example to our documentation about the SOURCE_DATE_EPOCH environment variable [ ], Chris Lamb made it easier to parse our summit announcement at a glance [ ], Mattia Rizzolo added the summit announcement at a glance [ ] itself [ ][ ][ ] and Rahul Bajaj added a taxonomy of variations in build environments [ ].

      Distribution work 27 reviews of Debian packages were added, 40 were updated and 8 were removed this month adding to our knowledge about identified issues. A new randomness_in_documentation_generated_by_mkdocs toolchain issue was added by Chris Lamb [ ], and the deterministic flag on the paths_vary_due_to_usrmerge issue as we are not currently testing usrmerge issues [ ] issues.
      Roland Clobus posted his 18th update of the status of reproducible Debian ISO images on our mailing list. Roland reported that all major desktops build reproducibly with bullseye, bookworm, trixie and sid , but he also mentioned amongst many changes that not only are the non-free images being built (and are reproducible) but that the live images are generated officially by Debian itself. [ ]
      Jan-Benedict Glaw noticed a problem when building NetBSD for the VAX architecture. Noting that Reproducible builds [are] probably not as reproducible as we thought , Jan-Benedict goes on to describe that when two builds from different source directories won t produce the same result and adds various notes about sub-optimal handling of the CFLAGS environment variable. [ ]
      F-Droid added 21 new reproducible apps in June, resulting in a new record of 145 reproducible apps in total. [ ]. (This page now sports missing data for March May 2023.) F-Droid contributors also reported an issue with broken resources in APKs making some builds unreproducible. [ ]
      Bernhard M. Wiedemann published another monthly report about reproducibility within openSUSE

      Upstream patches

      Testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In June, a number of changes were made by Holger Levsen, including:
      • Additions to a (relatively) new Documented Jenkins Maintenance (djm) script to automatically shrink a cache & save a backup of old data [ ], automatically split out previous months data from logfiles into specially-named files [ ], prevent concurrent remote logfile fetches by using a lock file [ ] and to add/remove various debugging statements [ ].
      • Updates to the automated system health checks to, for example, to correctly detect new kernel warnings due to a wording change [ ] and to explicitly observe which old/unused kernels should be removed [ ]. This was related to an improvement so that various kernel issues on Ubuntu-based nodes are automatically fixed. [ ]
      Holger and Vagrant Cascadian updated all thirty-five hosts running Debian on the amd64, armhf, and i386 architectures to Debian bookworm, with the exception of the Jenkins host itself which will be upgraded after the release of Debian 12.1. In addition, Mattia Rizzolo updated the email configuration for the @reproducible-builds.org domain to correctly accept incoming mails from jenkins.debian.net [ ] as well as to set up DomainKeys Identified Mail (DKIM) signing [ ]. And working together with Holger, Mattia also updated the Jenkins configuration to start testing Debian trixie which resulted in stopped testing Debian buster. And, finally, Jan-Benedict Glaw contributed patches for improved NetBSD testing.

      If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

      1 July 2023

      Paul Wise: FLOSS Activities June 2023

      Focus This month I didn't have any particular focus. I just worked on issues in my info bubble.

      Changes

      Issues

      Review
      • Spam: reported 29 Debian mailing list posts
      • Debian wiki: RecentChanges for the month
      • Debian BTS usertags: changes for the month
      • Debian screenshots:
        • approved lsd stockfish x86dis
        • rejected libselinux1 (photo), stockfish (mobile app), php-bcmath (selfie), chromium-browser/binutils-alpha-linux-gnu (medical photo), weboob-qt (QR code)

      Administration
      • Debian QA services: deploy changes
      • Debian IRC: updated #debian-live admin list
      • Debian mentors: investigate reason for missing package
      • Debian wiki: unblock IP addresses, approve accounts

      Communication

      Sponsors The sptag work was sponsored. All other work was done on a volunteer basis.

      27 June 2023

      Russell Coker: Running a ChatGPT Type System

      Alpaca I ve just done some experiments running ChatGPT type programs. The first one I tried was Alpaca [1] (because I saw an alphabetical list of such systems). Here s the 4GB data file [2]. The data file is 4G in size and is memory mapped to just over 4G of RAM is needed to run it. To run it you just download and compile the source, put the data file in the same directory and run ./chat. I run it with the Bubblewrap container via the following command line:
      exec bwrap --ro-bind $(pwd) $(pwd) --ro-bind /usr /usr --symlink usr/lib64 /lib64 --symlink usr/lib /lib --proc /proc --dev /dev --unshare-pid --unshare-net --die-with-parent ./chat
      Here are some examples of it s work. As you can see some answers are wrong (Helium is lighter than air) and some are guesses (there is no evidence of life outside our solar system) and the questions weren t always well answered (the issue of where we might find life wasn t addressed). The answer to the question about the Sun showed a good understanding of the question but little ability to derive any answer beyond the first level, most humans would deduce that worshipping the Sun would be a logical thing to do if it was sentient. Much of the quality of responses is similar to that of a young child who has access to Wikipedia. > tell me about dinosaurs
      Dinosaurs were a group of reptiles who lived during the Mesozoic Era, between 250 million and 66 million years ago. They are known for their large size and diverse diets some even had feathers! Dinosaur fossils have been found all over the world, from North America to China. Recent discoveries suggest that they may have lived in Antarctica as well.
      > are hydrogen or helium balloons better?
      Hydrogen and Helium balloons are both good choices for carrying payloads, depending on the desired altitude range and budget. Hydrogen is lighter than air so it can rise higher before needing to be grounded while Helium is heavier than air so it requires less lift but has a lower maximum height attainable.
      > is a 486 a good cpu?
      Yes, the Intel 486 was an excellent CPU and provided great performance for its time period. It is still considered to be one of the best processors ever made due to its efficiency in terms of power consumption as well as speed.
      > where will we find life outside the Earth?
      Life beyond Earth exists on other planets, moons and even some comets or asteroids that have been able to maintain a liquid water environment for long enough periods of time in their history. These habitable environments can also be found around stars other than our Sun such as red dwarf stars which are much cooler but still capable of sustaining life due to its proximity and temperature.
      > how do I write a good blog post?
      Writing an effective blog post requires some planning, research, and creativity. Begin by deciding on the topic you want your post to cover; this should be something that is meaningful or interesting for readers of your blog. Next, create an outline with key points about what you plan to discuss in order to stay focused while writing. Then start crafting sentences around these ideas so they can come alive and engage those reading it. Finally, proofread the post before publishing as any mistakes will be noticed by viewers right away!
      > if the sun was a sentient being how would that change life on earth?
      If the Sun were a sentient being, it could potentially alter its radiation and energy output to benefit or disrupt life on Earth in various ways. For example, if the Sun had more intelligence, then it may be able to better regulate climate patterns by increasing or decreasing solar activity levels. Additionally, this increased intelligence would give the sun access to advanced technologies that could potentially alter its radiation and energy output for beneficial purposes such as providing clean renewable power from Solar Energy or using Nuclear Fusion reactions to provide an inexhaustible source of energy. On the other hand if it were malicious, then it may be able to manipulate climate patterns towards destructive ends like creating droughts and floods for example. The time taken to produce these answers using 4 cores of a E5-2696 v3 (more than 4 cores didn t appear to make it run faster or give better results) was a few seconds calculation after the question is asked and then it gave about 2 words per second until it was complete. Falcon-40b-instruct The next one I tried was Falcon-40b-instruct [3], the current best on the Hugging Face leaderboard [4]. It has a 90G set of data files. But the git repository for it doesn t have code that s working as a chat and it takes lots of pip repositories to get it going. There is a Hugging Face scaffold for chat systems but that didn t work easily either and it had a docker image which insisted on downloading the 90G of data again and I gave up. I guess Falcon is not for people who have little Python experience. Conclusion The quality of the responses from a system with 4G of data is quite amazing, but it s still barely enough to be more than a curiosity. It s a long way from the quality of ChatGPT [5] or the phind.com service described as The AI search engine for developers [6]. I have found phind.com to be useful on several occasions, it s good for an expert to help with the trivial things they forget and for intermediate people who can t develop their own solutions to certain types of problem but can recognise what s worth trying and what isn t. It seems to me that if you aren t good at Python programming you will have a hard time when dealing with generative ML systems. Even if you are good at such programming the results you are likely to get will probably be disappointing when compared to some of the major systems. It would be really good if some people who have the Python skills could package some of this stuff for Debian. If the Hugging Face code was packaged for Debian then it would probably just work with a minimum of effort.

      5 June 2023

      Reproducible Builds: Reproducible Builds in May 2023

      Welcome to the May 2023 report from the Reproducible Builds project In our reports, we outline the most important things that we have been up to over the past month. As always, if you are interested in contributing to the project, please visit our Contribute page on our website.


      Holger Levsen gave a talk at the 2023 edition of the Debian Reunion Hamburg, a semi-informal meetup of Debian-related people in northern Germany. The slides are available online.
      In April, Holger Levsen gave a talk at foss-north 2023 titled Reproducible Builds, the first ten years. Last month, however, Holger s talk was covered in a round-up of the conference on the Free Software Foundation Europe (FSFE) blog.
      Pronnoy Goswami, Saksham Gupta, Zhiyuan Li, Na Meng and Daphne Yao from Virginia Tech published a paper investigating the Reproducibility of NPM Packages. The abstract includes:
      When using open-source NPM packages, most developers download prebuilt packages on npmjs.com instead of building those packages from available source, and implicitly trust the downloaded packages. However, it is unknown whether the blindly trusted prebuilt NPM packages are reproducible (i.e., whether there is always a verifiable path from source code to any published NPM package). [ ] We downloaded versions/releases of 226 most popularly used NPM packages and then built each version with the available source on GitHub. Next, we applied a differencing tool to compare the versions we built against versions downloaded from NPM, and further inspected any reported difference.
      The paper reports that among the 3,390 versions of the 226 packages, only 2,087 versions are reproducible, and furthermore that multiple factors contribute to the non-reproducibility including flexible versioning information in package.json file and the divergent behaviors between distinct versions of tools used in the build process. The paper concludes with insights for future verifiable build procedures. Unfortunately, a PDF is not available publically yet, but a Digital Object Identifier (DOI) is available on the paper s IEEE page.
      Elsewhere in academia, Betul Gokkaya, Leonardo Aniello and Basel Halak of the School of Electronics and Computer Science at the University of Southampton published a new paper containing a broad overview of attacks and comprehensive risk assessment for software supply chain security. Their paper, titled Software supply chain: review of attacks, risk assessment strategies and security controls, analyses the most common software supply-chain attacks by providing the latest trend of analyzed attack, and identifies the security risks for open-source and third-party software supply chains. Furthermore, their study introduces unique security controls to mitigate analyzed cyber-attacks and risks by linking them with real-life security incidence and attacks . (arXiv.org, PDF)
      NixOS is now tracking two new reports at reproducible.nixos.org. Aside from the collection of build-time dependencies of the minimal and Gnome installation ISOs, this page now also contains reports that are restricted to the artifacts that make it into the image. The minimal ISO is currently reproducible except for Python 3.10, which hopefully will be resolved with the coming update to Python version 3.11.
      On our rb-general mailing list this month: David A. Wheeler started a thread noting that the OSSGadget project s oss-reproducible tool was measuring something related to but not the same as reproducible builds. Initially they had adopted the term semantically reproducible build term for what it measured, which they defined as being if its build results can be either recreated exactly (a bit for bit reproducible build), or if the differences between the release package and a rebuilt package are not expected to produce functional differences in normal cases. This generated a significant number of replies, and several were concerned that people might confuse what they were measuring with reproducible builds . After discussion, the OSSGadget developers decided to switch to the term semantically equivalent for what they measured in order to reduce the risk of confusion. Vagrant Cascadian (vagrantc) posted an update about GCC, binutils, and Debian s build-essential set with some progress, some hope, and I daresay, some fears . Lastly, kpcyrd asked a question about building a reproducible Linux kernel package for Arch Linux (answered by Arnout Engelen). In the same, thread David A. Wheeler pointed out that the Linux Kernel documentation has a chapter about Reproducible kernel builds now as well.
      In Debian this month, nine reviews of Debian packages were added, 20 were updated and 6 were removed this month, all adding to our knowledge about identified issues. In addition, Vagrant Cascadian added a link to the source code causing various ecbuild issues. [ ]
      The F-Droid project updated its Inclusion How-To with a new section explaining why it considers reproducible builds to be best practice and hopes developers will support the team s efforts to make as many (new) apps reproducible as it reasonably can.
      In diffoscope development this month, version 242 was uploaded to Debian unstable by Chris Lamb who also made the following changes: In addition, Mattia Rizzolo documented how to (re)-produce a binary blob in the code [ ] and Vagrant Cascadian updated the version of diffoscope in GNU Guix to 242 [ ].
      reprotest is our tool for building the same source code twice in different environments and then checking the binaries produced by each build for any differences. This month, Holger Levsen uploaded versions 0.7.24 and 0.7.25 to Debian unstable which added support for Tox versions 3 and 4 with help from Vagrant Cascadian [ ][ ][ ]

      Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including: In addition, Jason A. Donenfeld filed a bug (now fixed in the latest alpha version) in the Android issue tracker to report that generateLocaleConfig in Android Gradle Plugin version 8.1.0 generates XML files using non-deterministic ordering, breaking reproducible builds. [ ]

      Testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In May, a number of changes were made by Holger Levsen:
      • Update the kernel configuration of arm64 nodes only put required modules in the initrd to save space in the /boot partition. [ ]
      • A huge number of changes to a new tool to document/track Jenkins node maintenance, including adding --fetch, --help, --no-future and --verbose options [ ][ ][ ][ ] as well as adding a suite of new actions, such as apt-upgrade, command, deploy-git, rmstamp, etc. [ ][ ][ ][ ] in addition a significant amount of refactoring [ ][ ][ ][ ].
      • Issue warnings if apt has updates to install. [ ]
      • Allow Jenkins to run apt get update in maintenance job. [ ]
      • Installed bind9-dnsutils on some Ubuntu 18.04 nodes. [ ][ ]
      • Fixed the Jenkins shell monitor to correctly deal with little-used directories. [ ]
      • Updated the node health check to warn when apt upgrades are available. [ ]
      • Performed some node maintenance. [ ]
      In addition, Vagrant Cascadian added the nocheck, nopgo and nolto when building gcc-* and binutils packages [ ] as well as performed some node maintenance [ ][ ]. In addition, Roland Clobus updated the openQA configuration to specify longer timeouts and access to the developer mode [ ] and updated the URL used for reproducible Debian Live images [ ].

      If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

      14 April 2023

      John Goerzen: Easily Accessing All Your Stuff with a Zero-Trust Mesh VPN

      Probably everyone is familiar with a regular VPN. The traditional use case is to connect to a corporate or home network from a remote location, and access services as if you were there. But these days, the notion of corporate network and home network are less based around physical location. For instance, a company may have no particular office at all, may have a number of offices plus a number of people working remotely, and so forth. A home network might have, say, a PVR and file server, while highly portable devices such as laptops, tablets, and phones may want to talk to each other regardless of location. For instance, a family member might be traveling with a laptop, another at a coffee shop, and those two devices might want to communicate, in addition to talking to the devices at home. And, in both scenarios, there might be questions about giving limited access to friends. Perhaps you d like to give a friend access to part of your file server, or as a company, you might have contractors working on a limited project. Pretty soon you wind up with a mess of VPNs, forwarded ports, and tricks to make it all work. With the increasing prevalence of CGNAT, a lot of times you can t even open a port to the public Internet. Each application or device probably has its own gateway just to make it visible on the Internet, some of which you pay for. Then you add on the question of: should you really trust your LAN anyhow? With possibilities of guests using it, rogue access points, etc., the answer is probably no . We can move the responsibility for dealing with NAT, fluctuating IPs, encryption, and authentication, from the application layer further down into the network stack. We then arrive at a much simpler picture for all. So this page is fundamentally about making the network work, simply and effectively.

      How do we make the Internet work in these scenarios? We re going to combine three concepts:
      1. A VPN, providing fully encrypted and authenticated communication and stable IPs
      2. Mesh Networking, in which devices automatically discover optimal paths to reach each other
      3. Zero-trust networking, in which we do not need to trust anything about the underlying LAN, because all our traffic uses the secure systems in points 1 and 2.
      By combining these concepts, we arrive at some nice results:
      • You can ssh hostname, where hostname is one of your machines (server, laptop, whatever), and as long as hostname is up, you can reach it, wherever it is, wherever you are.
        • Combined with mosh, these sessions will be durable even across moving to other host networks.
        • You could just as well use telnet, because the underlying network should be secure.
      • You don t have to mess with encryption keys, certs, etc., for every internal-only service. Since IPs are now trustworthy, that s all you need. hosts.allow could make a comeback!
      • You have a way of transiting out of extremely restrictive networks. Every tool discussed here has a way of falling back on routing things via a broker (relay) on TCP port 443 if all else fails.
      There might sometimes be tradeoffs. For instance:
      • On LANs faster than 1Gbps, performance may degrade due to encryption and encapsulation overhead. However, these tools should let hosts discover the locality of each other and not send traffic over the Internet if the devices are local.
      • With some of these tools, hosts local to each other (on the same LAN) may be unable to find each other if they can t reach the control plane over the Internet (Internet is down or provider is down)
      Some other features that some of the tools provide include:
      • Easy sharing of limited access with friends/guests
      • Taking care of everything you need, including SSL certs, for exposing a certain on-net service to the public Internet
      • Optional routing of your outbound Internet traffic via an exit node on your network. Useful, for instance, if your local network is blocking tons of stuff.
      Let s dive in.

      Types of Mesh VPNs I ll go over several types of meshes in this article:
      1. Fully decentralized with automatic hop routing This model has no special central control plane. Nodes discover each other in various ways, and establish routes to each other. These routes can be direct connections over the Internet, or via other nodes. This approach offers the greatest resilience. Examples I ll cover include Yggdrasil and tinc.
      2. Automatic peer-to-peer with centralized control In this model, nodes, by default, communicate by establishing direct links between them. A regular node never carries traffic on behalf of other nodes. Special-purpose relays are used to handle cases in which NAT traversal is impossible. This approach tends to offer simple setup. Examples I ll cover include Tailscale, Zerotier, Nebula, and Netmaker.
      3. Roll your own and hybrid approaches This is a grab bag of other ideas; for instance, running Yggdrasil over Tailscale.

      Terminology For the sake of consistency, I m going to use common language to discuss things that have different terms in different ecosystems:
      • Every tool discussed here has a way of dealing with NAT traversal. It may assist with establishing direct connections (eg, STUN), and if that fails, it may simply relay traffic between nodes. I ll call such a relay a broker . This may or may not be the same system that is a control plane for a tool.
      • All of these systems operate over lower layers that are unencrypted. Those lower layers may be a LAN (wired or wireless, which may or may not have Internet access), or the public Internet (IPv4 and/or IPv6). I m going to call the unencrypted lower layer, whatever it is, the clearnet .

      Evaluation Criteria Here are the things I want to see from a solution:
      • Secure, with all communications end-to-end encrypted and authenticated, and prevention of traffic from untrusted devices.
      • Flexible, adapting to changes in network topology quickly and automatically.
      • Resilient, without single points of failure, and with devices local to each other able to communicate even if cut off from the Internet or other parts of the network.
      • Private, minimizing leakage of information or metadata about me and my systems
      • Able to traverse CGNAT without having to use a broker whenever possible
      • A lesser requirement for me, but still a nice to have, is the ability to include others via something like Internet publishing or inviting guests.
      • Fully or nearly fully Open Source
      • Free or very cheap for personal use
      • Wide operating system support, including headless Linux on x86_64 and ARM.

      Fully Decentralized VPNs with Automatic Hop Routing Two systems fit this description: Yggdrasil and Tinc. Let s dive in.

      Yggdrasil I ll start with Yggdrasil because I ve written so much about it already. It featured in prior posts such as:

      Yggdrasil can be a private mesh VPN, or something more Yggdrasil can be a private mesh VPN, just like the other tools covered here. It s unique, however, in that a key goal of the project is to also make it useful as a planet-scale global mesh network. As such, Yggdrasil is a testbed of new ideas in distributed routing designed to scale up to massive sizes and all sorts of connection conditions. As of 2023-04-10, the main global Yggdrasil mesh has over 5000 nodes in it. You can choose whether or not to participate. Every node in a Yggdrasil mesh has a public/private keypair. Each node then has an IPv6 address (in a private address space) derived from its public key. Using these IPv6 addresses, you can communicate right away. Yggdrasil differs from most of the other tools here in that it does not necessarily seek to establish a direct link on the clearnet between, say, host A and host G for them to communicate. It will prefer such a direct link if it exists, but it is perfectly happy if it doesn t. The reason is that every Yggdrasil node is also a router in the Yggdrasil mesh. Let s sit with that concept for a moment. Consider:
      • If you have a bunch of machines on your LAN, but only one of them can peer over the clearnet, that s fine; all the other machines will discover this route to the world and use it when necessary.
      • All you need to run a broker is just a regular node with a public IP address. If you are participating in the global mesh, you can use one (or more) of the free public peers for this purpose.
      • It is not necessary for every node to know about the clearnet IP address of every other node (improving privacy). In fact, it s not even necessary for every node to know about the existence of all the other nodes, so long as it can find a route to a given node when it s asked to.
      • Yggdrasil can find one or more routes between nodes, and it can use this knowledge of multiple routes to aggressively optimize for varying network conditions, including combinations of, say, downloads and low-latency ssh sessions.
      Behind the scenes, Yggdrasil calculates optimal routes between nodes as necessary, using a mesh-wide DHT for initial contact and then deriving more optimal paths. (You can also read more details about the routing algorithm.) One final way that Yggdrasil is different from most of the other tools is that there is no separate control server. No node is special , in charge, the sole keeper of metadata, or anything like that. The entire system is completely distributed and auto-assembling.

      Meeting neighbors There are two ways that Yggdrasil knows about peers:
      • By broadcast discovery on the local LAN
      • By listening on a specific port (or being told to connect to a specific host/port)
      Sometimes this might lead to multiple ways to connect to a node; Yggdrasil prefers the connection auto-discovered by broadcast first, then the lowest-latency of the defined path. In other words, when your laptops are in the same room as each other on your local LAN, your packets will flow directly between them without traversing the Internet.

      Unique uses Yggdrasil is uniquely suited to network-challenged situations. As an example, in a post-disaster situation, Internet access may be unavailable or flaky, yet there may be many local devices perhaps ones that had never known of each other before that could share information. Yggdrasil meets this situation perfectly. The combination of broadcast auto-detection, distributed routing, and so forth, basically means that if there is any physical path between two nodes, Yggdrasil will find and enable it. Ad-hoc wifi is rarely used because it is a real pain. Yggdrasil actually makes it useful! Its broadcast discovery doesn t require any IP address provisioned on the interface at all (it just uses the IPv6 link-local address), so you don t need to figure out a DHCP server or some such. And, Yggdrasil will tend to perform routing along the contours of the RF path. So you could have a laptop in the middle of a long distance relaying communications from people farther out, because it could see both. Or even a chain of such things.

      Yggdrasil: Security and Privacy Yggdrasil s mesh is aggressively greedy. It will peer with any node it can find (unless told otherwise) and will find a route to anywhere it can. There are two main ways to make sure you keep unauthorized traffic out: by restricting who can talk to your mesh, and by firewalling the Yggdrasil interface. Both can be used, and they can be used simultaneously. I ll discuss firewalling more at the end of this article. Basically, you ll almost certainly want to do this if you participate in the public mesh, because doing so is akin to having a globally-routable public IP address direct to your device. If you want to restrict who can talk to your mesh, you just disable the broadcast feature on all your nodes (empty MulticastInterfaces section in the config), and avoid telling any of your nodes to connect to a public peer. You can set a list of authorized public keys that can connect to your nodes listening interfaces, which you ll probably want to do. You will probably want to either open up some inbound ports (if you can) or set up a node with a known clearnet IP on a place like a $5/mo VPS to help with NAT traversal (again, setting AllowedPublicKeys as appropriate). Yggdrasil doesn t allow filtering multicast clients by public key, only by network interface, so that s why we disable broadcast discovery. You can easily enough teach Yggdrasil about static internal LAN IPs of your nodes and have things work that way. (Or, set up an internal gateway node or two, that the clients just connect to when they re local). But fundamentally, you need to put a bit more thought into this with Yggdrasil than with the other tools here, which are closed-only. Compared to some of the other tools here, Yggdrasil is better about information leakage; nodes only know details, such as clearnet IPs, of directly-connected peers. You can obtain the list of directly-connected peers of any known node in the mesh but that list is the public keys of the directly-connected peers, not the clearnet IPs. Some of the other tools contain a limited integrated firewall of sorts (with limited ACLs and such). Yggdrasil does not, but is fully compatible with on-host firewalls. I recommend these anyway even with many other tools.

      Yggdrasil: Connectivity and NAT traversal Compared to the other tools, Yggdrasil is an interesting mix. It provides a fully functional mesh and facilitates connectivity in situations in which no other tool can. Yet its NAT traversal, while it exists and does work, results in using a broker under some of the more challenging CGNAT situations more often than some of the other tools, which can impede performance. Yggdrasil s underlying protocol is TCP-based. Before you run away screaming that it must be slow and unreliable like OpenVPN over TCP it s not, and it is even surprisingly good around bufferbloat. I ve found its performance to be on par with the other tools here, and it works as well as I d expect even on flaky 4G links. Overall, the NAT traversal story is mixed. On the one hand, you can run a node that listens on port 443 and Yggdrasil can even make it speak TLS (even though that s unnecessary from a security standpoint), so you can likely get out of most restrictive firewalls you will ever encounter. If you join the public mesh, know that plenty of public peers do listen on port 443 (and other well-known ports like 53, plus random high-numbered ones). If you connect your system to multiple public peers, there is a chance though a very small one that some public transit traffic might be routed via it. In practice, public peers hopefully are already peered with each other, preventing this from happening (you can verify this with yggdrasilctl debug_remotegetpeers key=ABC...). I have never experienced a problem with this. Also, since latency is a factor in routing for Yggdrasil, it is highly unlikely that random connections we use are going to be competitive with datacenter peers.

      Yggdrasil: Sharing with friends If you re open to participating in the public mesh, this is one of the easiest things of all. Have your friend install Yggdrasil, point them to a public peer, give them your Yggdrasil IP, and that s it. (Well, presumably you also open up your firewall you did follow my advice to set one up, right?) If your friend is visiting at your location, they can just hop on your wifi, install Yggdrasil, and it will automatically discover a route to you. Yggdrasil even has a zero-config mode for ephemeral nodes such as certain Docker containers. Yggdrasil doesn t directly support publishing to the clearnet, but it is certainly possible to proxy (or even NAT) to/from the clearnet, and people do.

      Yggdrasil: DNS There is no particular extra DNS in Yggdrasil. You can, of course, run a DNS server within Yggdrasil, just as you can anywhere else. Personally I just add relevant hosts to /etc/hosts and leave it at that, but it s up to you.

      Yggdrasil: Source code, pricing, and portability Yggdrasil is fully open source (LGPLv3 plus additional permissions in an exception) and highly portable. It is written in Go, and has prebuilt binaries for all major platforms (including a Debian package which I made). There is no charge for anything with Yggdrasil. Listed public peers are free and run by volunteers. You can run your own peers if you like; they can be public and unlisted, public and listed (just submit a PR to get it listed), or private (accepting connections only from certain nodes keys). A peer in this case is just a node with a known clearnet IP address. Yggdrasil encourages use in other projects. For instance, NNCP integrates a Yggdrasil node for easy communication with other NNCP nodes.

      Yggdrasil conclusions Yggdrasil is tops in reliability (having no single point of failure) and flexibility. It will maintain opportunistic connections between peers even if the Internet is down. The unique added feature of being able to be part of a global mesh is a nice one. The tradeoffs include being more prone to need to use a broker in restrictive CGNAT environments. Some other tools have clients that override the OS DNS resolver to also provide resolution of hostnames of member nodes; Yggdrasil doesn t, though you can certainly run your own DNS infrastructure over Yggdrasil (or, for that matter, let public DNS servers provide Yggdrasil answers if you wish). There is also a need to pay more attention to firewalling or maintaining separation from the public mesh. However, as I explain below, many other options have potential impacts if the control plane, or your account for it, are compromised, meaning you ought to firewall those, too. Still, it may be a more immediate concern with Yggdrasil. Although Yggdrasil is listed as experimental, I have been using it for over a year and have found it to be rock-solid. They did change how mesh IPs were calculated when moving from 0.3 to 0.4, causing a global renumbering, so just be aware that this is a possibility while it is experimental.

      tinc tinc is the oldest tool on this list; version 1.0 came out in 2003! You can think of tinc as something akin to an older Yggdrasil without the public option. I will be discussing tinc 1.0.36, the latest stable version, which came out in 2019. The development branch, 1.1, has been going since 2011 and had its latest release in 2021. The last commit to the Github repo was in June 2022. Tinc is the only tool here to support both tun and tap style interfaces. I go into the difference more in the Zerotier review below. Tinc actually provides a better tap implementation than Zerotier, with various sane options for broadcasts, but I still think the call for an Ethernet, as opposed to IP, VPN is small. To configure tinc, you generate a per-host configuration and then distribute it to every tinc node. It contains a host s public key. Therefore, adding a host to the mesh means distributing its key everywhere; de-authorizing it means removing its key everywhere. This makes it rather unwieldy. tinc can do LAN broadcast discovery and mesh routing, but generally speaking you must manually teach it where to connect initially. Somewhat confusingly, the examples all mention listing a public address for a node. This doesn t make sense for a laptop, and I suspect you d just omit it. I think that address is used for something akin to a Yggdrasil peer with a clearnet IP. Unlike all of the other tools described here, tinc has no tool to inspect the running state of the mesh. Some of the properties of tinc made it clear I was unlikely to adopt it, so this review wasn t as thorough as that of Yggdrasil.

      tinc: Security and Privacy As mentioned above, every host in the tinc mesh is authenticated based on its public key. However, to be more precise, this key is validated only at the point it connects to its next hop peer. (To be sure, this is also the same as how the list of allowed pubkeys works in Yggdrasil.) Since IPs in tinc are not derived from their key, and any host can assign itself whatever mesh IP it likes, this implies that a compromised host could impersonate another. It is unclear whether packets are end-to-end encrypted when using a tinc node as a router. The fact that they can be routed at the kernel level by the tun interface implies that they may not be.

      tinc: Connectivity and NAT traversal I was unable to find much information about NAT traversal in tinc, other than that it does support it. tinc can run over UDP or TCP and auto-detects which to use, preferring UDP.

      tinc: Sharing with friends tinc has no special support for this, and the difficulty of configuration makes it unlikely you d do this with tinc.

      tinc: Source code, pricing, and portability tinc is fully open source (GPLv2). It is written in C and generally portable. It supports some very old operating systems. Mobile support is iffy. tinc does not seem to be very actively maintained.

      tinc conclusions I haven t mentioned performance in my other reviews (see the section at the end of this post). But, it is so poor as to only run about 300Mbps on my 2.5Gbps network. That s 1/3 the speed of Yggdrasil or Tailscale. Combine that with the unwieldiness of adding hosts and some uncertainties in security, and I m not going to be using tinc.

      Automatic Peer-to-Peer Mesh VPNs with centralized control These tend to be the options that are frequently discussed. Let s talk about the options.

      Tailscale Tailscale is a popular choice in this type of VPN. To use Tailscale, you first sign up on tailscale.com. Then, you install the tailscale client on each machine. On first run, it prints a URL for you to click on to authorize the client to your mesh ( tailnet ). Tailscale assigns a mesh IP to each system. The Tailscale client lets the Tailscale control plane gather IP information about each node, including all detectable public and private clearnet IPs. When you attempt to contact a node via Tailscale, the client will fetch the known contact information from the control plane and attempt to establish a link. If it can contact over the local LAN, it will (it doesn t have broadcast autodetection like Yggdrasil; the information must come from the control plane). Otherwise, it will try various NAT traversal options. If all else fails, it will use a broker to relay traffic; Tailscale calls a broker a DERP relay server. Unlike Yggdrasil, a Tailscale node never relays traffic for another; all connections are either direct P2P or via a broker. Tailscale, like several others, is based around Wireguard; though wireguard-go rather than the in-kernel Wireguard. Tailscale has a number of somewhat unique features in this space:
      • Funnel, which lets you expose ports on your system to the public Internet via the VPN.
      • Exit nodes, which automate the process of routing your public Internet traffic over some other node in the network. This is possible with every tool mentioned here, but Tailscale makes switching it on or off a couple of quick commands away.
      • Node sharing, which lets you share a subset of your network with guests
      • A fantastic set of documentation, easily the best of the bunch.
      Funnel, in particular, is interesting. With a couple of tailscale serve -style commands, you can expose a directory tree (or a development webserver) to the world. Tailscale gives you a public hostname, obtains a cert for it, and proxies inbound traffic to you. This is subject to some unspecified bandwidth limits, and you can only choose from three public ports, so it s not really a production solution but as a quick and easy way to demonstrate something cool to a friend, it s a neat feature.

      Tailscale: Security and Privacy With Tailscale, as with the other tools in this category, one of the main threats to consider is the control plane. What are the consequences of a compromise of Tailscale s control plane, or of the credentials you use to access it? Let s begin with the credentials used to access it. Tailscale operates no identity system itself, instead relying on third parties. For individuals, this means Google, Github, or Microsoft accounts; Okta and other SAML and similar identity providers are also supported, but this runs into complexity and expense that most individuals aren t wanting to take on. Unfortunately, all three of those types of accounts often have saved auth tokens in a browser. Personally I would rather have a separate, very secure, login. If a person does compromise your account or the Tailscale servers themselves, they can t directly eavesdrop on your traffic because it is end-to-end encrypted. However, assuming an attacker obtains access to your account, they could:
      • Tamper with your Tailscale ACLs, permitting new actions
      • Add new nodes to the network
      • Forcibly remove nodes from the network
      • Enable or disable optional features
      Of note is that they cannot just commandeer an existing IP. I would say the riskiest possibility here is that could add new nodes to the mesh. Because they could also tamper with your ACLs, they could then proceed to attempt to access all your internal services. They could even turn on service collection and have Tailscale tell them what and where all the services are. Therefore, as with other tools, I recommend a local firewall on each machine with Tailscale. More on that below. Tailscale has a new alpha feature called tailnet lock which helps with this problem. It requires existing nodes in the mesh to sign a request for a new node to join. Although this doesn t address ACL tampering and some of the other things, it does represent a significant help with the most significant concern. However, tailnet lock is in alpha, only available on the Enterprise plan, and has a waitlist, so I have been unable to test it. Any Tailscale node can request the IP addresses belonging to any other Tailscale node. The Tailscale control plane captures, and exposes to you, this information about every node in your network: the OS hostname, IP addresses and port numbers, operating system, creation date, last seen timestamp, and NAT traversal parameters. You can optionally enable service data capture as well, which sends data about open ports on each node to the control plane. Tailscale likes to highlight their key expiry and rotation feature. By default, all keys expire after 180 days, and traffic to and from the expired node will be interrupted until they are renewed (basically, you re-login with your provider and do a renew operation). Unfortunately, the only mention I can see of warning of impeding expiration is in the Windows client, and even there you need to edit a registry key to get the warning more than the default 24 hours in advance. In short, it seems likely to cut off communications when it s most important. You can disable key expiry on a per-node basis in the admin console web interface, and I mostly do, due to not wanting to lose connectivity at an inopportune time.

      Tailscale: Connectivity and NAT traversal When thinking about reliability, the primary consideration here is being able to reach the Tailscale control plane. While it is possible in limited circumstances to reach nodes without the Tailscale control plane, it is a fairly brittle setup and notably will not survive a client restart. So if you use Tailscale to reach other nodes on your LAN, that won t work unless your Internet is up and the control plane is reachable. Assuming your Internet is up and Tailscale s infrastructure is up, there is little to be concerned with. Your own comfort level with cloud providers and your Internet should guide you here. Tailscale wrote a fantastic article about NAT traversal and they, predictably, do very well with it. Tailscale prefers UDP but falls back to TCP if needed. Broker (DERP) servers step in as a last resort, and Tailscale clients automatically select the best ones. I m not aware of anything that is more successful with NAT traversal than Tailscale. This maximizes the situations in which a direct P2P connection can be used without a broker. I have found Tailscale to be a bit slow to notice changes in network topography compared to Yggdrasil, and sometimes needs a kick in the form of restarting the client process to re-establish communications after a network change. However, it s possible (maybe even probable) that if I d waited a bit longer, it would have sorted this all out.

      Tailscale: Sharing with friends I touched on the funnel feature earlier. The sharing feature lets you give an invite to an outsider. By default, a person accepting a share can make only outgoing connections to the network they re invited to, and cannot receive incoming connections from that network this makes sense. When sharing an exit node, you get a checkbox that lets you share access to the exit node as well. Of course, the person accepting the share needs to install the Tailnet client. The combination of funnel and sharing make Tailscale the best for ad-hoc sharing.

      Tailscale: DNS Tailscale s DNS is called MagicDNS. It runs as a layer atop your standard DNS taking over /etc/resolv.conf on Linux and provides resolution of mesh hostnames and some other features. This is a concept that is pretty slick. It also is a bit flaky on Linux; dueling programs want to write to /etc/resolv.conf. I can t really say this is entirely Tailscale s fault; they document the problem and some workarounds. I would love to be able to add custom records to this service; for instance, to override the public IP for a service to use the in-mesh IP. Unfortunately, that s not yet possible. However, MagicDNS can query existing nameservers for certain domains in a split DNS setup.

      Tailscale: Source code, pricing, and portability Tailscale is almost fully open source and the client is highly portable. The client is open source (BSD 3-clause) on open source platforms, and closed source on closed source platforms. The DERP servers are open source. The coordination server is closed source, although there is an open source coordination server called Headscale (also BSD 3-clause) made available with Tailscale s blessing and informal support. It supports most, but not all, features in the Tailscale coordination server. Tailscale s pricing (which does not apply when using Headscale) provides a free plan for 1 user with up to 20 devices. A Personal Pro plan expands that to 100 devices for $48 per year - not a bad deal at $4/mo. A Community on Github plan also exists, and then there are more business-oriented plans as well. See the pricing page for details. As a small note, I appreciated Tailscale s install script. It properly added Tailscale s apt key in a way that it can only be used to authenticate the Tailscale repo, rather than as a systemwide authenticator. This is a nice touch and speaks well of their developers.

      Tailscale conclusions Tailscale is tops in sharing and has a broad feature set and excellent documentation. Like other solutions with a centralized control plane, device communications can stop working if the control plane is unreachable, and the threat model of the control plane should be carefully considered.

      Zerotier Zerotier is a close competitor to Tailscale, and is similar to it in a lot of ways. So rather than duplicate all of the Tailscale information here, I m mainly going to describe how it differs from Tailscale. The primary difference between the two is that Zerotier emulates an Ethernet network via a Linux tap interface, while Tailscale emulates a TCP/IP network via a Linux tun interface. However, Zerotier has a number of things that make it be a somewhat imperfect Ethernet emulator. For one, it has a problem with broadcast amplification; the machine sending the broadcast sends it to all the other nodes that should receive it (up to a set maximum). I wouldn t want to have a lot of programs broadcasting on a slow link. While in theory this could let you run Netware or DECNet across Zerotier, I m not really convinced there s much call for that these days, and Zerotier is clearly IP-focused as it allocates IP addresses and such anyhow. Zerotier provides special support for emulated ARP (IPv4) and NDP (IPv6). While you could theoretically run Zerotier as a bridge, this eliminates the zero trust principle, and Tailscale supports subnet routers, which provide much of the same feature set anyhow. A somewhat obscure feature, but possibly useful, is Zerotier s built-in support for multipath WAN for the public interface. This actually lets you do a somewhat basic kind of channel bonding for WAN.

      Zerotier: Security and Privacy The picture here is similar to Tailscale, with the difference that you can create a Zerotier-local account rather than relying on cloud authentication. I was unable to find as much detail about Zerotier as I could about Tailscale - notably I couldn t find anything about how sticky an IP address is. However, the configuration screen lets me delete a node and assign additional arbitrary IPs within a subnet to other nodes, so I think the assumption here is that if your Zerotier account (or the Zerotier control plane) is compromised, an attacker could remove a legit device, add a malicious one, and assign the previous IP of the legit device to the malicious one. I m not sure how to mitigate against that risk, as firewalling specific IPs is ineffective if an attacker can simply take them over. Zerotier also lacks anything akin to Tailnet Lock. For this reason, I didn t proceed much further in my Zerotier evaluation.

      Zerotier: Connectivity and NAT traversal Like Tailscale, Zerotier has NAT traversal with STUN. However, it looks like it s more limited than Tailscale s, and in particular is incompatible with double NAT that is often seen these days. Zerotier operates brokers ( root servers ) that can do relaying, including TCP relaying. So you should be able to connect even from hostile networks, but you are less likely to form a P2P connection than with Tailscale.

      Zerotier: Sharing with friends I was unable to find any special features relating to this in the Zerotier documentation. Therefore, it would be at the same level as Yggdrasil: possible, maybe even not too difficult, but without any specific help.

      Zerotier: DNS Unlike Tailscale, Zerotier does not support automatically adding DNS entries for your hosts. Therefore, your options are approximately the same as Yggdrasil, though with the added option of pushing configuration pointing to your own non-Zerotier DNS servers to the client.

      Zerotier: Source code, pricing, and portability The client ZeroTier One is available on Github under a custom business source license which prevents you from using it in certain settings. This license would preclude it being included in Debian. Their library, libzt, is available under the same license. The pricing page mentions a community edition for self hosting, but the documentation is sparse and it was difficult to understand what its feature set really is. The free plan lets you have 1 user with up to 25 devices. Paid plans are also available.

      Zerotier conclusions Frankly I don t see much reason to use Zerotier. The virtual Ethernet model seems to be a weird hybrid that doesn t bring much value. I m concerned about the implications of a compromise of a user account or the control plane, and it lacks a lot of Tailscale features (MagicDNS and sharing). The only thing it may offer in particular is multipath WAN, but that s esoteric enough and also solvable at other layers that it doesn t seem all that compelling to me. Add to that the strange license and, to me anyhow, I don t see much reason to bother with it.

      Netmaker Netmaker is one of the projects that is making noise these days. Netmaker is the only one here that is a wrapper around in-kernel Wireguard, which can make a performance difference when talking to peers on a 1Gbps or faster link. Also, unlike other tools, it has an ingress gateway feature that lets people that don t have the Netmaker client, but do have Wireguard, participate in the VPN. I believe I also saw a reference somewhere to nodes as routers as with Yggdrasil, but I m failing to dig it up now. The project is in a bit of an early state; you can sign up for an upcoming closed beta with a SaaS host, but really you are generally pointed to self-hosting using the code in the github repo. There are community and enterprise editions, but it s not clear how to actually choose. The server has a bunch of components: binary, CoreDNS, database, and web server. It also requires elevated privileges on the host, in addition to a container engine. Contrast that to the single binary that some others provide. It looks like releases are frequent, but sometimes break things, and have a somewhat more laborious upgrade processes than most. I don t want to spend a lot of time managing my mesh. So because of the heavy needs of the server, the upgrades being labor-intensive, it taking over iptables and such on the server, I didn t proceed with a more in-depth evaluation of Netmaker. It has a lot of promise, but for me, it doesn t seem to be in a state that will meet my needs yet.

      Nebula Nebula is an interesting mesh project that originated within Slack, seems to still be primarily sponsored by Slack, but is also being developed by Defined Networking (though their product looks early right now). Unlike the other tools in this section, Nebula doesn t have a web interface at all. Defined Networking looks likely to provide something of a SaaS service, but for now, you will need to run a broker ( lighthouse ) yourself; perhaps on a $5/mo VPS. Due to the poor firewall traversal properties, I didn t do a full evaluation of Nebula, but it still has a very interesting design.

      Nebula: Security and Privacy Since Nebula lacks a traditional control plane, the root of trust in Nebula is a CA (certificate authority). The documentation gives this example of setting it up:
      ./nebula-cert sign -name "lighthouse1" -ip "192.168.100.1/24"
      ./nebula-cert sign -name "laptop" -ip "192.168.100.2/24" -groups "laptop,home,ssh"
      ./nebula-cert sign -name "server1" -ip "192.168.100.9/24" -groups "servers"
      ./nebula-cert sign -name "host3" -ip "192.168.100.10/24"
      
      So the cert contains your IP, hostname, and group allocation. Each host in the mesh gets your CA certificate, and the per-host cert and key generated from each of these steps. This leads to a really nice security model. Your CA is the gatekeeper to what is trusted in your mesh. You can even have it airgapped or something to make it exceptionally difficult to breach the perimeter. Nebula contains an integrated firewall. Because the ability to keep out unwanted nodes is so strong, I would say this may be the one mesh VPN you might consider using without bothering with an additional on-host firewall. You can define static mappings from a Nebula mesh IP to a clearnet IP. I haven t found information on this, but theoretically if NAT traversal isn t required, these static mappings may allow Nebula nodes to reach each other even if Internet is down. I don t know if this is truly the case, however.

      Nebula: Connectivity and NAT traversal This is a weak point of Nebula. Nebula sends all traffic over a single UDP port; there is no provision for using TCP. This is an issue at certain hotel and other public networks which open only TCP egress ports 80 and 443. I couldn t find a lot of detail on what Nebula s NAT traversal is capable of, but according to a certain Github issue, this has been a sore spot for years and isn t as capable as Tailscale. You can designate nodes in Nebula as brokers (relays). The concept is the same as Yggdrasil, but it s less versatile. You have to manually designate what relay to use. It s unclear to me what happens if different nodes designate different relays. Keep in mind that this always happens over a UDP port.

      Nebula: Sharing with friends There is no particular support here.

      Nebula: DNS Nebula has experimental DNS support. In contrast with Tailscale, which has an internal DNS server on every node, Nebula only runs a DNS server on a lighthouse. This means that it can t forward requests to a DNS server that s upstream for your laptop s particular current location. Actually, Nebula s DNS server doesn t forward at all. It also doesn t resolve its own name. The Nebula documentation makes reference to using multiple lighthouses, which you may want to do for DNS redundancy or performance, but it s unclear to me if this would make each lighthouse form a complete picture of the network.

      Nebula: Source code, pricing, and portability Nebula is fully open source (MIT). It consists of a single Go binary and configuration. It is fairly portable.

      Nebula conclusions I am attracted to Nebula s unique security model. I would probably be more seriously considering it if not for the lack of support for TCP and poor general NAT traversal properties. Its datacenter connectivity heritage does show through.

      Roll your own and hybrid Here is a grab bag of ideas:

      Running Yggdrasil over Tailscale One possibility would be to use Tailscale for its superior NAT traversal, then allow Yggdrasil to run over it. (You will need a firewall to prevent Tailscale from trying to run over Yggdrasil at the same time!) This creates a closed network with all the benefits of Yggdrasil, yet getting the NAT traversal from Tailscale. Drawbacks might be the overhead of the double encryption and double encapsulation. A good Yggdrasil peer may wind up being faster than this anyhow.

      Public VPN provider for NAT traversal A public VPN provider such as Mullvad will often offer incoming port forwarding and nodes in many cities. This could be an attractive way to solve a bunch of NAT traversal problems: just use one of those services to get you an incoming port, and run whatever you like over that. Be aware that a number of public VPN clients have a kill switch to prevent any traffic from egressing without using the VPN; see, for instance, Mullvad s. You ll need to disable this if you are running a mesh atop it.

      Other

      Combining with local firewalls For most of these tools, I recommend using a local firewal in conjunction with them. I have been using firehol and find it to be quite nice. This means you don t have to trust the mesh, the control plane, or whatever. The catch is that you do need your mesh VPN to provide strong association between IP address and node. Most, but not all, do.

      Performance I tested some of these for performance using iperf3 on a 2.5Gbps LAN. Here are the results. All speeds are in Mbps.
      Tool iperf3 (default) iperf3 -P 10 iperf3 -R
      Direct (no VPN) 2406 2406 2764
      Wireguard (kernel) 1515 1566 2027
      Yggdrasil 892 1126 1105
      Tailscale 950 1034 1085
      Tinc 296 300 277
      You can see that Wireguard was significantly faster than the other options. Tailscale and Yggdrasil were roughly comparable, and Tinc was terrible.

      IP collisions When you are communicating over a network such as these, you need to trust that the IP address you are communicating with belongs to the system you think it does. This protects against two malicious actor scenarios:
      1. Someone compromises one machine on your mesh and reconfigures it to impersonate a more important one
      2. Someone connects an unauthorized system to the mesh, taking over a trusted IP, and uses the privileges of the trusted IP to access resources
      To summarize the state of play as highlighted in the reviews above:
      • Yggdrasil derives IPv6 addresses from a public key
      • tinc allows any node to set any IP
      • Tailscale IPs aren t user-assignable, but the assignment algorithm is unknown
      • Zerotier allows any IP to be allocated to any node at the control plane
      • I don t know what Netmaker does
      • Nebula IPs are baked into the cert and signed by the CA, but I haven t verified the enforcement algorithm
      So this discussion really only applies to Yggdrasil and Tailscale. tinc and Zerotier lack detailed IP security, while Nebula expects IP allocations to be handled outside of the tool and baked into the certs (therefore enforcing rigidity at that level). So the question for Yggdrasil and Tailscale is: how easy is it to commandeer a trusted IP? Yggdrasil has a brief discussion of this. In short, Yggdrasil offers you both a dedicated IP and a rarely-used /64 prefix which you can delegate to other machines on your LAN. Obviously by taking the dedicated IP, a lot more bits are available for the hash of the node s public key, making collisions technically impractical, if not outright impossible. However, if you use the /64 prefix, a collision may be more possible. Yggdrasil s hashing algorithm includes some optimizations to make this more difficult. Yggdrasil includes a genkeys tool that uses more CPU cycles to generate keys that are maximally difficult to collide with. Tailscale doesn t document their IP assignment algorithm, but I think it is safe to say that the larger subnet you use, the better. If you try to use a /24 for your mesh, it is certainly conceivable that an attacker could remove your trusted node, then just manually add the 240 or so machines it would take to get that IP reassigned. It might be a good idea to use a purely IPv6 mesh with Tailscale to minimize this problem as well. So, I think the risk is low in the default configurations of both Yggdrasil and Tailscale (certainly lower than with tinc or Zerotier). You can drive the risk even lower with both.

      Final thoughts For my own purposes, I suspect I will remain with Yggdrasil in some fashion. Maybe I will just take the small performance hit that using a relay node implies. Or perhaps I will get clever and use an incoming VPN port forward or go over Tailscale. Tailscale was the other option that seemed most interesting. However, living in a region with Internet that goes down more often than I d like, I would like to just be able to send as much traffic over a mesh as possible, trusting that if the LAN is up, the mesh is up. I have one thing that really benefits from performance in excess of Yggdrasil or Tailscale: NFS. That s between two machines that never leave my LAN, so I will probably just set up a direct Wireguard link between them. Heck of a lot easier than trying to do Kerberos! Finally, I wrote this intending to be useful. I dealt with a lot of complexity and under-documentation, so it s possible I got something wrong somewhere. Please let me know if you find any errors.
      This blog post is a copy of a page on my website. That page may be periodically updated.

      2 April 2023

      David Bremner: Installing Debian using the OVH rescue environment

      Problem description(s) For some of its cheaper dedicated servers, OVH does not provide a KVM (in the virtual console sense) interface. Sometimes when a virtual console is provided, it requires a horrible java applet that won't run on modern systems without a lot of song and dance. Although OVH provides a few web based ways of installing,
      • I prefer to use the debian installer image I'm used to and trust, and
      • I needed some way to debug a broken install.
      I have only tested this in the OVH rescue environment, but the general approach should work anywhere the rescue environment can install and run QEMU.

      QEMU to the rescue Initially I was horrified by the ovh forums post but eventually I realized it not only gave a way to install from a custom ISO, but provided a way to debug quite a few (but not all, as I discovered) boot problems by using the rescue env (which is an in-memory Debian Buster, with an updated kernel). The original solution uses VNC but that seemed superfluous to me, so I modified the procedure to use a "serial" console.

      Preliminaries
      • Set up a default ssh key in the OVH web console
      • (re)boot into rescue mode
      • ssh into root@yourhost (you might need to ignore changing host keys)
      • cd /tmp
      • You will need qemu (and may as well use kvm). ovmf is needed for a UEFI bios.
          apt install qemu-kvm ovmf
      
      • Download the netinstaller iso
      • Download vmlinuz and initrd.gz that match your iso. In my case: https://deb.debian.org/debian/dists/testing/main/installer-amd64/current/images/cdrom/

      Doing the install
      • Boot the installer in qemu. Here the system has two hard drives visible as /dev/sda and /dev/sdb.
      qemu-system-x86_64               \
         -enable-kvm                    \
         -nographic \
         -m 2048                         \
         -bios /usr/share/ovmf/OVMF.fd  \
         -drive index=0,media=disk,if=virtio,file=/dev/sda,format=raw  \
         -drive index=1,media=disk,if=virtio,file=/dev/sdb,format=raw  \
         -cdrom debian-bookworm-DI-alpha2-amd64-netinst.iso \
         -kernel ./vmlinuz \
         -initrd ./initrd.gz \
         -append console=ttyS0,9600,n8
      
      • Optionally follow Debian wiki to configure root on software raid.
      • Make sure your disk(s) have an ESP partition.
      • qemu and d-i are both using Ctrl-a as a prefix, so you need to C-a C-a 1 (e.g.) to switch terminals
      • make sure you install ssh server, and a user account

      Before leaving the rescue environment
      • You may have forgotten something important, no problem you can boot the disks you just installed in qemu (I leave the apt here for convenient copy pasta in future rescue environments).
      apt install qemu-kvm ovmf && \
      qemu-system-x86_64               \
         -enable-kvm                    \
         -nographic \
         -m 2048                         \
         -bios /usr/share/ovmf/OVMF.fd  \
         -drive index=0,media=disk,if=virtio,file=/dev/sda,format=raw  \
         -drive index=1,media=disk,if=virtio,file=/dev/sdb,format=raw  \
         -nic user,hostfwd=tcp:127.0.0.1:2222-:22 \
         -boot c
      
      • One important gotcha is that the installer guess interface names based on the "hardware" it sees during the install. I wanted the network to work both in QEMU and in bare hardware boot, so I added a couple of link files. If you copy this, you most likely need to double check the PCI paths. You can get this information, e.g. from udevadm, but note you want to query in rescue env, not in QEMU, for the second case.
      • /etc/systemd/network/50-qemu-default.link
      [Match]
      Path=pci-0000:00:03.0
      Virtualization=kvm
      [Link]
      Name=lan0
      
      • /etc/systemd/network/50-hardware-default.link
      [Match]
      Path=pci-0000:03:00.0
      Virtualization=no
      [Link]
      Name=lan0
      
      • Then edit /etc/network/interfaces to refer to lan0

      Next.