Getting the Belgian eID to work on Linux systems should be fairly easy, although some people do struggle with it. For that reason, there is a lot of third-party documentation out there in the form of blog posts, wiki pages, and other kinds of things. Unfortunately, some of this documentation is simply wrong. Written by people who played around with things until it kind of worked, sometimes you get a situation where something that used to work in the past (but wasn't really necessary) now stopped working, but it's still added to a number of locations as though it were the gospel. And then people follow these instructions and now things don't work anymore. One of these revolves around OpenSC. OpenSC is an open source smartcard library that has support for a pretty large number of smartcards, amongst which the Belgian eID. It provides a PKCS#11 module as well as a number of supporting tools. For those not in the know, PKCS#11 is a standardized C API for offloading cryptographic operations. It is an API that can be used when talking to a hardware cryptographic module, in order to make that module perform some actions, and it is especially popular in the open source world, with support in NSS, amongst others. This library is written and maintained by mozilla, and is a low-level cryptographic library that is used by Firefox (on all platforms it supports) as well as by Google Chrome and other browsers based on that (but only on Linux, and as I understand it, only for linking with smartcards; their BoringSSL library is used for other things). The official eID software that we ship through eid.belgium.be, also known as "BeID", provides a PKCS#11 module for the Belgian eID, as well as a number of support tools to make interacting with the card easier, such as the "eID viewer", which provides the ability to read data from the card, and validate their signatures. While the very first public version of this eID PKCS#11 module was originally based on OpenSC, it has since been reimplemented as a PKCS#11 module in its own right, with no lineage to OpenSC whatsoever anymore. About five years ago, the Belgian eID card was renewed. At the time, a new physical appearance was the most obvious difference with the old card, but there were also some technical, on-chip, differences that are not so apparent. The most important one here, although it is not the only one, is the fact that newer eID cards now use a NIST P-384 elliptic curve-based private keys, rather than the RSA-based ones that were used in the past. This change required some changes to any PKCS#11 module that supports the eID; both the BeID one, as well as the OpenSC card-belpic driver that is written in support of the Belgian eID. Obviously, the required changes were implemented for the BeID module; however, the OpenSC card-belpic driver was not updated. While I did do some preliminary work on the required changes, I was unable to get it to work, and eventually other things took up my time so I never finished the implementation. If someone would like to finish the work that I started, the preliminal patch that I wrote could be a good start -- but like I said, it doesn't yet work. Also, you'll probably be interested in the official documentation of the eID card. Unfortunately, in the mean time someone added the Applet 1.8 ATR to the card-belpic.c file, without also implementing the required changes to the driver so that the PKCS#11 driver actually supports the eID card. The result of this is that if you have OpenSC installed in NSS for either Firefox or any Chromium-based browser, and it gets picked up before the BeID PKCS#11 module, then NSS will stop looking and pass all crypto operations to the OpenSC PKCS#11 module rather than to the official eID PKCS#11 module, and things will not work at all, causing a lot of confusion. I have therefore taken the following two steps:

The official eID packages now conflict with the OpenSC PKCS#11 module. Specifically only the PKCS#11 module, not the rest of OpenSC, so you can theoretically still use its tools. This means that once we release this new version of the eID software, when you do an upgrade and you have OpenSC installed, it will remove the PKCS#11 module and anything that depends on it. This is normal and expected.
I have filed a pull request against OpenSC that removes the Applet 1.8 ATR from the driver, so that OpenSC will stop claiming that it supports the 1.8 applet.

When the pull request is accepted, we will update the official eID software to make the conflict versioned, so that as soon as it works again you will again be able to install the OpenSC and BeID packages at the same time. In the mean time, if you have the OpenSC PKCS#11 module installed on your system, and your eID authentication does not work, try removing it.

ceb and I are members of the Derril Water Solar Park cooperative. We were recently invited to vote on whether the coop should bid for a Contract for Difference, in a government green electricity auction. We ve voted No.

Green electricity from your mainstream supplier is a lie For a while

ceb and I have wanted to contribute directly to green energy provision. This isn t really possible in the mainstream consumer electricy market. Mainstream electricity suppliers 100% green energy tariffs are pure greenwashing. In a capitalist boondoogle, they basically divvy up the electricity so that customers on the (typically more expensive) green tariff get the green electricity, and the other customers get whatever is left. (Of course the electricity is actually all mixed up by the National Grid.) There are fewer people signed up for these tariffs than there is green power generated, so this basically means signing up for a green tariff has no effect whatsoever, other than giving evil people more money. Ripple About a year ago we heard about Ripple. The structure is a little complicated, but the basic upshot is: Ripple promote and manage renewable energy schemes. The schemes themselves are each an individual company; the company is largely owned by a co-operative. The co-op is owned by consumers of electricity in the UK., To stop the co-operative being an purely financial investment scheme, shares ownership is limited according to your electricity usage. The electricity is be sold on the open market, and the profits are used to offset members electricity bills. (One gotcha from all of this is that for this to work your electricity billing provider has to be signed up with Ripple, but ours, Octopus, is.) It seemed to us that this was a way for us to directly cause (and pay for!) the actual generation of green electricity. So, we bought shares in one these co-operatives: we are co-owners of the Derril Water Solar Farm. We signed up for the maximum: funding generating capacity corresponding to 120% of our current electricity usage. We paid a little over 5000 for our shares. Contracts for Difference The UK has a renewable energy subsidy scheme, which goes by the name of Contracts for Difference. The idea is that a renewable energy generation company bids in advance, saying that they ll sell their electricity at Y price, for the duration of the contract (15 years in the current round). The lowest bids win. All the electricity from the participating infrastructure is sold on the open market, but if the market price is low the government makes up the difference, and if the price is high, the government takes the winnings. This is supposedly good for giving a stable investment environment, since the price the developer is going to get now doesn t depends on the electricity market over the next 15 years. The CfD system is supposed to encourage development, so you can only apply before you ve commissioned your generation infrastructure. Ripple and CfD Ripple recently invited us to agree that the Derril Water co-operative should bid in the current round of CfDs. If this goes ahead, and we are one of the auction s winners, the result would be that, instead of selling our electricity at the market price, we ll sell it at the fixed CfD price. This would mean that our return on our investment (which show up as savings on our electricity bills) would be decoupled from market electricity prices, and be much more predictable. They can t tell us the price they d want to bid at, and future electricity prices are rather hard to predict, but it s clear from the accompanying projections that they think we d be better off on average with a CfD. The documentation is very full of financial projections and graphs; other factors aren t really discussed in any detail. The rules of the co-op didn t require them to hold a vote, but very sensibly, for such a fundamental change in the model, they decided to treat it roughly the same way as for a rules change: they re hoping to get 75% Yes votes. Voting No The reason we re in this co-op at all is because we want to directly fund renewable electricity. Participating in the CfD auction would involve us competing with capitalist energy companies for government subsidies. Subsidies which are supposed to encourage the provision of green electricity. It seems to us that participating in this auction would remove most of the difference between what we hoped to do by investing in Derril Water, and just participating in the normal consumer electricity market. In particular, if we do win in the auction, that s probably directly removing the funding and investment support model for other, market-investor-funded, projects. In other words, our buying into Derril Water ceases to be an additional green energy project, changing (in its minor way) the UK s electricity mix. It becomes a financial transaction much more tenously connected (if connected at all) to helping mitigate the climate emergency. So our conclusion was that we must vote against.

comments

Today at $WORK I needed to add the private company Certificate Authority (CA) to Firefox, and I found the steps were unnecessarily complex. Time to blog about that, and I also made a Debian wiki article of that post, so that future generations can update the information, when Firefox 742 is released on Debian 17. The cacert certificate authority is not included in Debian and Firefox, and is thus a good example of adding a private CA. Note that this does not mean I specifically endorse that CA.

Test that SSL connections to a site signed by the private CA is failing

$ gnutls-cli wiki.cacert.org:443
...
- Status: The certificate is NOT trusted. The certificate issuer is unknown. 
*** PKI verification of server certificate failed...
*** Fatal error: Error in the certificate.

Download the private CA

$ wget http://www.cacert.org/certs/root_X0F.crt

test that a connection works with the private CA

$ gnutls-cli --x509cafile root_X0F.crt wiki.cacert.org:443
...
- Status: The certificate is trusted. 
- Description: (TLS1.2-X.509)-(ECDHE-SECP256R1)-(RSA-SHA256)-(AES-256-GCM)
- Session ID: 37:56:7A:89:EA:5F:13:E8:67:E4:07:94:4B:52:23:63:1E:54:31:69:5D:70:17:3C:D0:A4:80:B0:3A:E5:22:B3
- Options: safe renegotiation,
- Handshake was completed
...

add the private CA to the Debian trust store located in /etc/ssl/certs/ca-certificates.crt

$ sudo cp root_X0F.crt /usr/local/share/ca-certificates/cacert-org-root-ca.crt
$ sudo update-ca-certificates --verbose
...
Adding debian:cacert-org-root-ca.pem
...

verify that we can connect without passing the private CA on the command line

$ gnutls-cli wiki.cacert.org:443
... 
 - Status: The certificate is trusted.

At that point most applications are able to connect to systems with a certificate signed by the private CA (curl, Gnome builtin Browser ). However Firefox is using its own trust store and will still display a security error if connecting to https://wiki.cacert.org. To make Firefox trust the Debian trust store, we need to add a so called security device, in fact an extra library wrapping the Debian trust store. The library will wrap the Debian trust store in the PKCS#11 industry format that Firefox supports.
install the pkcs#11 wrapping library and command line tools

$ sudo apt install p11-kit p11-kit-modules

verify that the private CA is accessible via PKCS#11

$ trust list   grep --context 2 'CA Cert'
pkcs11:id=%16%B5%32%1B%D4%C7%F3%E0%E6%8E%F3%BD%D2%B0%3A%EE%B2%39%18%D1;type=cert
    type: certificate
    label: CA Cert Signing Authority
    trust: anchor
    category: authority

now we need to add a new security device in Firefox pointing to the pkcs11 trust store. The pkcs11 trust store is located in /usr/lib/x86_64-linux-gnu/pkcs11/p11-kit-trust.so

$ dpkg --listfiles p11-kit-modules   grep trust
/usr/lib/x86_64-linux-gnu/pkcs11/p11-kit-trust.so

in Firefox (tested in version 115 esr), go to Settings -> Privacy & Security -> Security -> Security Devices.
Then click Load , in the popup window use My local trust as a module name, and /usr/lib/x86_64-linux-gnu/pkcs11/p11-kit-trust.so as a module filename. After adding the module, you should see it in the list of Security Devices, having /etc/ssl/certs/ca-certificates.crt as a description.
now restart Firefox and you should be able to browse https://wiki.cacert.org without security errors

A woman wearing a white top with a wide neck with ruffles and puffy sleeves that are gathered at the cuff. The top is tucked in the trousers to gather the fullness at the waist.

After making my Elastic Neck Top I knew I wanted to make another one less constrained by the amount of available fabric. I had a big cut of white cotton voile, I bought some more swimsuit elastic, and I also had a spool of n 100 sewing cotton, but then I postponed the project for a while I was working on other things. Then FOSDEM 2024 arrived, I was going to remote it, and I was working on my Augusta Stays, but I knew that in the middle of FOSDEM I risked getting to the stage where I needed to leave the computer to try the stays on: not something really compatible with the frenetic pace of a FOSDEM weekend, even one spent at home. I needed a backup project¹, and this was perfect: I already had everything I needed, the pattern and instructions were already on my site (so I didn t need to take pictures while working), and it was mostly a lot of straight seams, perfect while watching conference videos. So, on the Friday before FOSDEM I cut all of the pieces, then spent three quarters of FOSDEM on the stays, and when I reached the point where I needed to stop for a fit test I started on the top. Like the first one, everything was sewn by hand, and one week after I had started everything was assembled, except for the casings for the elastic at the neck and cuffs, which required about 10 km of sewing, and even if it was just a running stitch it made me want to reconsider my lifestyle choices a few times: there was really no reason for me not to do just those seams by machine in a few minutes. Instead I kept sewing by hand whenever I had time for it, and on the next weekend it was ready. We had a rare day of sun during the weekend, so I wore my thermal underwear, some other layer, a scarf around my neck, and went outside with my SO to have a batch of pictures taken (those in the jeans posts, and others for a post I haven t written yet. Have I mentioned I have a backlog?). And then the top went into the wardrobe, and it will come out again when the weather will be a bit warmer. Or maybe it will be used under the Augusta Stays, since I don t have a 1700 chemise yet, but that requires actually finishing them. The pattern for this project was already online, of course, but I ve added a picture of the casing to the relevant section, and everything is as usual #FreeSoftWear.

yes, I could have worked on some knitting WIP, but lately I m more in a sewing mood.

In light of the recent cancellation of the queer.af domain registration by the Taliban, the fragile and difficult nature of country-code top-level domains (ccTLDs) has once again been comprehensively demonstrated. Since many people may not be aware of the risks, I thought I d give a solid explainer of the whole situation, and explain why you should, in general, not have anything to do with domains which are registered under ccTLDs.

Top-level What-Now? A top-level domain (TLD) is the last part of a domain name (the collection of words, separated by periods, after the `https://` in your web browser s location bar). It s the com in `example.com`, or the af in `queer.af`. There are two kinds of TLDs: country-code TLDs (ccTLDs) and generic TLDs (gTLDs). Despite all being TLDs, they re very different beasts under the hood.

What s the Difference? Generic TLDs are what most organisations and individuals register their domains under: old-school technobabble like com , net , or org , historical oddities like gov , and the new-fangled world of words like tech , social , and bank . These gTLDs are all regulated under a set of rules created and administered by ICANN (the Internet Corporation for Assigned Names and Numbers ), which try to ensure that things aren t a complete wild-west, limiting things like price hikes (well, sometimes, anyway), and providing means for disputes over names¹. Country-code TLDs, in contrast, are all two letters long², and are given out to countries to do with as they please. While ICANN kinda-sorta has something to do with ccTLDs (in the sense that it makes them exist on the Internet), it has no authority to control how a ccTLD is managed. If a country decides to raise prices by 100x, or cancel all registrations that were made on the 12th of the month, there s nothing anyone can do about it. If that sounds bad, that s because it is. Also, it s not a theoretical problem the Taliban deciding to asssert its bigotry over the little corner of the Internet namespace it has taken control of is far from the first time that ccTLDs have caused grief.

Shifting Sands The `queer.af` cancellation is interesting because, at the time the domain was reportedly registered, 2018, Afghanistan had what one might describe as, at least, a different political climate. Since then, of course, things have changed, and the new bosses have decided to get a bit more active. Those running `queer.af` seem to have seen the writing on the wall, and were planning on moving to another, less fraught, domain, but hadn t completed that move when the Taliban came knocking.

The Curious Case of Brexit When the United Kingdom decided to leave the European Union, it fell foul of the EU s rules for the registration of domains under the eu ccTLD³. To register (and maintain) a domain name ending in `.eu`, you have to be a resident of the EU. When the UK ceased to be part of the EU, residents of the UK were no longer EU residents. Cue much unhappiness, wailing, and gnashing of teeth when this was pointed out to Britons. Some decided to give up their domains, and move to other parts of the Internet, while others managed to hold onto them by various legal sleight-of-hand (like having an EU company maintain the registration on their behalf). In any event, all very unpleasant for everyone involved.

Geopolitics on the Internet?!? After Russia invaded Ukraine in February 2022, the Ukranian Vice Prime Minister asked ICANN to suspend ccTLDs associated with Russia. While ICANN said that it wasn t going to do that, because it wouldn t do anything useful, some domain registrars (the companies you pay to register domain names) ceased to deal in Russian ccTLDs, and some websites restricted links to domains with Russian ccTLDs. Whether or not you agree with the sort of activism implied by these actions, the fact remains that even the actions of a government that aren t directly related to the Internet can have grave consequences for your domain name if it s registered under a ccTLD. I don t think any gTLD operator will be invading a neighbouring country any time soon.

Money, Money, Money, Must Be Funny When you register a domain name, you pay a registration fee to a registrar, who does administrative gubbins and causes you to be able to control the domain name in the DNS. However, you don t own that domain name⁴ you re only renting it. When the registration period comes to an end, you have to renew the domain name, or you ll cease to be able to control it. Given that a domain name is typically your brand or identity online, the chances are you d prefer to keep it over time, because moving to a new domain name is a massive pain, having to tell all your customers or users that now you re somewhere else, plus having to accept the risk of someone registering the domain name you used to have and capturing your traffic it s all a gigantic hassle. For gTLDs, ICANN has various rules around price increases and bait-and-switch pricing that tries to keep a lid on the worst excesses of registries. While there are any number of reasonable criticisms of the rules, and the Internet community has to stay on their toes to keep ICANN from totally succumbing to regulatory capture, at least in the gTLD space there s some degree of control over price gouging. On the other hand, ccTLDs have no effective controls over their pricing. For example, in 2008 the Seychelles increased the price of `.sc` domain names from US$25 to US$75. No reason, no warning, just pay up .

Who Is Even Getting That Money? A closely related concern about ccTLDs is that some of the cool ones are assigned to countries that are not great. The poster child for this is almost certainly Libya, which has the ccTLD ly . While Libya was being run by a terrorist-supporting extremist, companies thought it was a great idea to have domain names that ended in `.ly`. These domain registrations weren t (and aren t) cheap, and it s hard to imagine that at least some of that money wasn t going to benefit the Gaddafi regime. Similarly, the British Indian Ocean Territory, which has the io ccTLD, was created in a colonialist piece of chicanery that expelled thousands of native Chagossians from Diego Garcia. Money from the registration of `.io` domains doesn t go to the (former) residents of the Chagos islands, instead it gets paid to the UK government. Again, I m not trying to suggest that all gTLD operators are wonderful people, but it s not particularly likely that the direct beneficiaries of the operation of a gTLD stole an island chain and evicted the residents.

Are ccTLDs Ever Useful? The answer to that question is an unqualified maybe . I certainly don t think it s a good idea to register a domain under a ccTLD for vanity purposes: because it makes a word, is the same as a file extension you like, or because it looks cool. Those ccTLDs that clearly represent and are associated with a particular country are more likely to be OK, because there is less impetus for the registry to try a naked cash grab. Unfortunately, ccTLD registries have a disconcerting habit of changing their minds on whether they serve their geographic locality, such as when auDA decided to declare an open season in the `.au` namespace some years ago. Essentially, while a ccTLD may have geographic connotations now, there s not a lot of guarantee that they won t fall victim to scope creep in the future. Finally, it might be somewhat safer to register under a ccTLD if you live in the location involved. At least then you might have a better idea of whether your domain is likely to get pulled out from underneath you. Unfortunately, as the `.eu` example shows, living somewhere today is no guarantee you ll still be living there tomorrow, even if you don t move house. In short, I d suggest sticking to gTLDs. They re at least lower risk than ccTLDs.

+1, Helpful If you ve found this post informative, why not buy me a refreshing beverage? My typing fingers (both of them) thank you in advance for your generosity.

Footnotes

don t make the mistake of thinking that I approve of ICANN or how it operates; it s an omnishambles of poor governance and incomprehensible decision-making.

corresponding roughly, though not precisely (because everything has to be complicated, because humans are complicated), to the entries in the ISO standard for Codes for the representation of names of countries and their subdivisions , ISO 3166.

yes, the EU is not a country; it s part of the roughly, though not precisely caveat mentioned previously.

despite what domain registrars try very hard to imply, without falling foul of deceptive advertising regulations.

New Year, Same Great People! Our Debian User Group met for the first of our 2024 bi-monthly meetings on February 4th and it was loads of fun. Around twelve different people made it this time to Koumbit, where the meeting happened. As a reminder, our meetings are called "Debian & Stuff" because we want to be as open as possible and welcome people that want to work on "other stuff" than Debian. Here is what we did: pollo:

tested a laptop that had a defective battery with a known good one (the problem was indeed with the battery :D)
renewed his expiring OpenPGP key
worked on removing trapperkeeper-scheduler-clojure from the DebCI reject_list
helped anarcat with packaging sigal
managed to feed most of the people present :)

LeLutin:

worked with lavamind to upload new upstream release of smokeping

mjeanson:

migrated from lxd to incus on his servers
helped anarcat with flashing his AirGradient

lavamind:

submitted a bug report on r-cran-rserve (promptly fixed/uploaded by maintainer!)
reviewed and uploaded smokeping
bug triaged the facter package
worked on puppet-agent new upstream version 8.4.0

viashimo:

updated puppet-strings from 2.9.0 to 4.2.1
reported upstream test failures on puppet-strings with recent versions of mdl

tvaz & tassia:

drafted a call & request for funding for the Vanier College FLOSS Club hardware marathon at Eastern Bloc
worked on an application to conduct research at Vanier College on Debian usability
babysitted :-)

joeDoe:

worked on his AirGradient
debugged the WiFi and VPN setup on his new laptop

anarcat:

worked on packaging sigal
worked on flashing his AirGradient boards
rewrote a Prometheus exporter for Airgradient devices
brought over a car full of old computer gear to donate

Pictures I was pretty busy this time around and ended up not taking a lot of pictures. Here's a bad one of the ceiling at Koumbit I took, and a picture by anarcat of the content of his boxes of loot: A picture of the ceiling at Koumbit

Now that I m freelancing, I need to actually track my time, which is something I ve had the luxury of not having to do before. That meant something of a rethink of the way I ve been keeping track of my to-do list. Up to now that was a combination of things like the bug lists for the projects I m working on at the moment, whatever task tracking system Canonical was using at the moment (Jira when I left), and a giant flat text file in which I recorded logbook-style notes of what I d done each day plus a few extra notes at the bottom to remind myself of particularly urgent tasks. I could have started manually adding times to each logbook entry, but ugh, let s not. In general, I had the following goals (which were a bit reminiscent of my address book):

free software throughout
storage under my control
ability to annotate tasks with URLs (especially bugs and merge requests)
lightweight time tracking (I m OK with having to explicitly tell it when I start and stop tasks)
ability to drive everything from the command line
decent filtering so I don t have to look at my entire to-do list all the time
ability to easily generate billing information for multiple clients
optionally, integration with Android (mainly so I can tick off personal tasks like change bedroom lightbulb or whatever that don t involve being near a computer)

I didn t do an elaborate evaluation of multiple options, because I m not trying to come up with the best possible solution for a client here. Also, there are a bazillion to-do list trackers out there and if I tried to evaluate them all I d never do anything else. I just wanted something that works well enough for me. Since it came up on Mastodon: a bunch of people swear by Org mode, which I know can do at least some of this sort of thing. However, I don t use Emacs and don t plan to use Emacs. nvim-orgmode does have some support for time tracking, but when I ve tried vim-based versions of Org mode in the past I ve found they haven t really fitted my brain very well. Taskwarrior and Timewarrior One of the other Freexian collaborators mentioned Taskwarrior and Timewarrior, so I had a look at those. The basic idea of Taskwarrior is that you have a task command that tracks each task as a blob of JSON and provides subcommands to let you add, modify, and remove tasks with a minimum of friction. task add adds a task, and you can add metadata like project:Personal (I always make sure every task has a project, for ease of filtering). Just running task shows you a task list sorted by Taskwarrior s idea of urgency, with an ID for each task, and there are various other reports with different filtering and verbosity. task <id> annotate lets you attach more information to a task.

task <id>
done

marks it as done. So far so good, so a redacted version of my to-do list looks like this:

$ task ls
ID A Project     Tags                 Description
17   Freexian                         Add Incus support to autopkgtest [2]
 7   Columbiform                      Figure out Lloyds online banking [1]
 2   Debian                           Fix troffcvt for groff 1.23.0 [1]
11   Personal                         Replace living room curtain rail

Once I got comfortable with it, this was already a big improvement. I haven t bothered to learn all the filtering gadgets yet, but it was easy enough to see that I could do something like task all project:Personal and it d show me both pending and completed tasks in that project, and that all the data was stored in ~/.task - though I have to say that there are enough reporting bells and whistles that I haven t needed to poke around manually. In combination with the regular backups that I do anyway (you do too, right?), this gave me enough confidence to abandon my previous text-file logbook approach. Next was time tracking. Timewarrior integrates with Taskwarrior, albeit in an only semi-packaged way, and it was easy enough to set that up. Now I can do:

$ task 25 start
Starting task 00a9516f 'Write blog post about task tracking'.
Started 1 task.
Note: '"Write blog post about task tracking"' is a new tag.
Tracking Columbiform "Write blog post about task tracking"
  Started 2024-01-10T11:28:38
  Current                  38
  Total               0:00:00
You have more urgent tasks.
Project 'Columbiform' is 25% complete (3 of 4 tasks remaining).

When I stop work on something, I do task active to find the ID, then

task
<id> stop

. Timewarrior does the tedious stopwatch business for me, and I can manually enter times if I forget to start/stop a task. Then the really useful bit: I can do something like timew summary :month <name-of-client> and it tells me how much to bill that client for this month. Perfect. I also started using VIT to simplify the day-to-day flow a little, which means I m normally just using one or two keystrokes rather than typing longer commands. That isn t really necessary from my point of view, but it does save some time. Android integration I left Android integration for a bit later since it wasn t essential. When I got round to it, I have to say that it felt a bit clumsy, but it did eventually work. The first step was to set up a taskserver. Most of the setup procedure was OK, but I wanted to use Let s Encrypt to minimize the amount of messing around with CAs I had to do. Getting this to work involved hitting things with sticks a bit, and there s still a local CA involved for client certificates. What I ended up with was a certbot setup with the webroot authenticator and a custom deploy hook as follows (with cert_name replaced by a DNS name in my house domain):

#! /bin/sh
set -eu
cert_name=taskd.example.org
found=false
for domain in $RENEWED_DOMAINS; do
    case "$domain" in
        $cert_name)
            found=:
            ;;
    esac
done
$found   exit 0
install -m 644 "/etc/letsencrypt/live/$cert_name/fullchain.pem" \
    /var/lib/taskd/pki/fullchain.pem
install -m 640 -g Debian-taskd "/etc/letsencrypt/live/$cert_name/privkey.pem" \
    /var/lib/taskd/pki/privkey.pem
systemctl restart taskd.service

I could then set this in /etc/taskd/config (server.crl.pem and ca.cert.pem were generated using the documented taskserver setup procedure):

server.key=/var/lib/taskd/pki/privkey.pem
server.cert=/var/lib/taskd/pki/fullchain.pem
server.crl=/var/lib/taskd/pki/server.crl.pem
ca.cert=/var/lib/taskd/pki/ca.cert.pem

Then I could set taskd.ca on my laptop to /usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt and otherwise follow the client setup instructions, run task sync init to get things started, and then task sync every so often to sync changes between my laptop and the taskserver. I used TaskWarrior Mobile as the client. I have to say I wouldn t want to use that client as my primary task tracking interface: the setup procedure is clunky even beyond the necessity of copying a client certificate around, it expects you to give it a .taskrc rather than having a proper settings interface for that, and it only seems to let you add a task if you specify a due date for it. It also lacks Timewarrior integration, so I can only really use it when I don t care about time tracking, e.g. personal tasks. But that s really all I need, so it meets my minimum requirements. Next? Considering this is literally the first thing I tried, I have to say I m pretty happy with it. There are a bunch of optional extras I haven t tried yet, but in general it kind of has the vim nature for me: if I need something it s very likely to exist or easy enough to build, but the features I don t use don t get in my way. I wouldn t recommend any of this to somebody who didn t already spend most of their time in a terminal - but I do. I m glad people have gone to all the effort to build this so I didn t have to.

Welcome to the December 2023 report from the Reproducible Builds project! In these reports we outline the most important things that we have been up to over the past month. As a rather rapid recap, whilst anyone may inspect the source code of free software for malicious flaws, almost all software is distributed to end users as pre-compiled binaries (more).

Reproducible Builds: Increasing the Integrity of Software Supply Chains awarded IEEE Software Best Paper award In February 2022, we announced in these reports that a paper written by Chris Lamb and Stefano Zacchiroli was now available in the March/April 2022 issue of IEEE Software. Titled Reproducible Builds: Increasing the Integrity of Software Supply Chains (PDF). This month, however, IEEE Software announced that this paper has won their Best Paper award for 2022.

Reproducibility to affect package migration policy in Debian In a post summarising the activities of the Debian Release Team at a recent in-person Debian event in Cambridge, UK, Paul Gevers announced a change to the way packages are migrated into the staging area for the next stable Debian release based on its reproducibility status:
The folks from the Reproducibility Project have come a long way since they started working on it 10 years ago, and we believe it s time for the next step in Debian. Several weeks ago, we enabled a migration policy in our migration software that checks for regression in reproducibility. At this moment, that is presented as just for info, but we intend to change that to delays in the not so distant future. We eventually want all packages to be reproducible. To stimulate maintainers to make their packages reproducible now, we ll soon start to apply a bounty [speedup] for reproducible builds, like we ve done with passing autopkgtests for years. We ll reduce the bounty for successful autopkgtests at that moment in time.

Speranza: Usable, privacy-friendly software signing Kelsey Merrill, Karen Sollins, Santiago Torres-Arias and Zachary Newman have developed a new system called Speranza, which is aimed at reassuring software consumers that the product they are getting has not been tampered with and is coming directly from a source they trust. A write-up on TechXplore.com goes into some more details:
What we have done, explains Sollins, is to develop, prove correct, and demonstrate the viability of an approach that allows the [software] maintainers to remain anonymous. Preserving anonymity is obviously important, given that almost everyone software developers included value their confidentiality. This new approach, Sollins adds, simultaneously allows [software] users to have confidence that the maintainers are, in fact, legitimate maintainers and, furthermore, that the code being downloaded is, in fact, the correct code of that maintainer. [ ]
The corresponding paper is published on the arXiv preprint server in various formats, and the announcement has also been covered in MIT News.

Nondeterministic Git bundles Paul Baecher published an interesting blog post on Reproducible git bundles. For those who are not familiar with them, Git bundles are used for the offline transfer of Git objects without an active server sitting on the other side of a network connection. Anyway, Paul wrote about writing a backup system for his entire system, but:
I noticed that a small but fixed subset of [Git] repositories are getting backed up despite having no changes made. That is odd because I would think that repeated bundling of the same repository state should create the exact same bundle. However [it] turns out that for some, repositories bundling is nondeterministic.
Paul goes on to to describe his solution, which involves forcing git to be single threaded makes the output deterministic . The article was also discussed on Hacker News.

Output from libxlst now deterministic

libxslt is the XSLT C library developed for the GNOME project, where XSLT itself is an XML language to define transformations for XML files. This month, it was revealed that the result of the generate-id() XSLT function is now deterministic across multiple transformations, fixing many issues with reproducible builds. As the Git commit by Nick Wellnhofer describes:

Rework the generate-id() function to return deterministic values. We use
a simple incrementing counter and store ids in the 'psvi' member of
nodes which was freed up by previous commits. The presence of an id is
indicated by a new "source node" flag.
This fixes long-standing problems with reproducible builds, see
https://bugzilla.gnome.org/show_bug.cgi?id=751621
This also hardens security, as the old implementation leaked the
difference between a heap and a global pointer, see
https://bugs.chromium.org/p/chromium/issues/detail?id=1356211
The old implementation could also generate the same id for dynamically
created nodes which happened to reuse the same memory. Ids for namespace
nodes were completely broken. They now use the id of the parent element
together with the hex-encoded namespace prefix.

Community updates There were made a number of improvements to our website, including Chris Lamb fixing the `generate-draft` script to not blow up if the input files have been corrupted today or even in the past [ ], Holger Levsen updated the Hamburg 2023 summit to add a link to farewell post [ ] & to add a picture of a Post-It note. [ ], and Pol Dellaiera updated the paragraph about `tar` and the `--clamp-mtime` flag [ ]. On our mailing list this month, Bernhard M. Wiedemann posted an interesting summary on some of the reasons why packages are still not reproducible in 2023. diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes, including processing `objdump` symbol comment filter inputs as Python `byte` (and not `str`) instances [ ] and Vagrant Cascadian extended diffoscope support for GNU Guix [ ] and updated the version in that distribution to version 253 [ ].

Challenges of Producing Software Bill Of Materials for Java Musard Balliu, Benoit Baudry, Sofia Bobadilla, Mathias Ekstedt, Martin Monperrus, Javier Ron, Aman Sharma, Gabriel Skoglund, C sar Soto-Valero and Martin Wittlinger (!) of the KTH Royal Institute of Technology in Sweden, have published an article in which they:
deep-dive into 6 tools and the accuracy of the SBOMs they produce for complex open-source Java projects. Our novel insights reveal some hard challenges regarding the accurate production and usage of software bills of materials.
The paper is available on arXiv.

Debian Non-Maintainer campaign As mentioned in previous reports, the Reproducible Builds team within Debian has been organising a series of online and offline sprints in order to clear the huge backlog of reproducible builds patches submitted by performing so-called NMUs (Non-Maintainer Uploads). During December, Vagrant Cascadian performed a number of such uploads, including:

`crack` [ ] (#1021521 & #1021522)

`dustmite` [ ] (#1020878 & #1020879)

`edid-decode` [ ] (#1020877)

`gentoo` [ ] (#1024284)

`haskell98-report` [ ] (#1024007)

`infinipath-psm` [ ] (#990862)

`lcm` [ ] (#1024286)

`libapache-mod-evasive` [ ] (#1020800)

`libccrtp` [ ] (#860470)

`libinput` [ ] (#995809)

`lirc` [ ] (#979019, #979023 & #979024)

`mm-common` [ ] (#977177)

`mpl-sphinx-theme` [ ] (#1005826)

`psi` [ ] (#1017473)

`python-parse-type` [ ] (#1002671)

`ruby-tioga` [ ] (#1005727)

`ucspi-proxy` [ ] (#1024125)

`ypserv` [ ] (#983138)

In addition, Holger Levsen performed three no-source-change NMUs in order to address the last packages without `.buildinfo` files in Debian trixie, specifically `lorene` (0.0.0~cvs20161116+dfsg-1.1), `maria` (1.3.5-4.2) and `ruby-rinku` (1.7.3-2.1).

Reproducibility 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 December, a number of changes were made by Holger Levsen:

Debian-related changes:

Fix matching packages for the [R programming language](https://en.wikipedia.org/wiki/R_(programming_language). [ ][ ][ ]

Add a Certbot configuration for the Nginx web server. [ ]

Enable debugging for the `create-meta-pkgs` tool. [ ][ ]

Arch Linux-related changes

The `asp` has been deprecated by `pkgctl`; thanks to dvzrv for the pointer. [ ]

Disable the Arch Linux builders for now. [ ]

Stop referring to the `/trunk` branch / subdirectory. [ ]

Use `--protocol https` when cloning repositories using the `pkgctl` tool. [ ]

Misc changes:

Install the `python3-setuptools` and `swig` packages, which are now needed to build OpenWrt. [ ]

Install `pkg-config` needed to build Coreboot artifacts. [ ]

Detect failures due to an issue where the `fakeroot` tool is implicitly required but not automatically installed. [ ]

Detect failures due to rename of the `vmlinuz` file. [ ]

Improve the grammar of an error message. [ ]

Document that `freebsd-jenkins.debian.net` has been updated to FreeBSD 14.0. [ ]

In addition, node maintenance was performed by Holger Levsen [ ] and 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:

Bernhard M. Wiedemann:

`apr` (hostname issue)

`dune` (parallelism)

`epy` (time-based `.pyc` issue)

`fpc` (Year 2038)

`gap` (date)

`gh` (FTBFS in 2024)

`kubernetes` (fixed random build path)

`libgda` (date)

`libguestfs` (tar)

`metamail` (date)

`mpi-selector` (date)

`neovim` (randomness in Lua)

`nml` (time-based `.pyc`)

`pommed` (parallelism)

`procmail` (benchmarking)

`pysnmp` (FTBFS in 2038)

`python-efl` (drop Sphinx doctrees)

`python-pyface` (time)

`python-pytest-salt-factories` (time-based `.pyc` issue)

`python-quimb` (fails to build on single-CPU systems)

`python-rdflib` (random)

`python-yarl` (random path)

`qt6-webengine` (parallelism issue in documentation)

`texlive` (Gzip modification time issue)

`waf` (time-based `.pyc`)

`warewulf` (CPIO modification time and inode issue)

`xemacs` (toolchain hostname)

Chris Lamb:

#1057710 filed against `python-aiostream`.

#1057721 filed against `openpyxl`.

#1058681 filed against `python-multipletau`.

#1059013 filed against `wxmplot`.

#1059014 filed against `stunnel4`.

James Addison:

#1059592 & #1059631 filed against `qttools-opensource-src`.

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:

IRC: `#reproducible-builds` on `irc.oftc.net`.

Mailing list: `rb-general@lists.reproducible-builds.org`

Mastodon: @reproducible_builds

Twitter: @ReproBuilds

Debian Public Statement about the EU Cyber Resilience Act and the Product Liability Directive The European Union is currently preparing a regulation "on horizontal cybersecurity requirements for products with digital elements" known as the Cyber Resilience Act (CRA). It is currently in the final "trilogue" phase of the legislative process. The act includes a set of essential cybersecurity and vulnerability handling requirements for manufacturers. It will require products to be accompanied by information and instructions to the user. Manufacturers will need to perform risk assessments and produce technical documentation and, for critical components, have third-party audits conducted. Discovered security issues will have to be reported to European authorities within 25 hours (1). The CRA will be followed up by the Product Liability Directive (PLD) which will introduce compulsory liability for software. While a lot of these regulations seem reasonable, the Debian project believes that there are grave problems for Free Software projects attached to them. Therefore, the Debian project issues the following statement:

Free Software has always been a gift, freely given to society, to take and to use as seen fit, for whatever purpose. Free Software has proven to be an asset in our digital age and the proposed EU Cyber Resilience Act is going to be detrimental to it. a. As the Debian Social Contract states, our goal is "make the best system we can, so that free works will be widely distributed and used." Imposing requirements such as those proposed in the act makes it legally perilous for others to redistribute our work and endangers our commitment to "provide an integrated system of high-quality materials with no legal restrictions that would prevent such uses of the system". (2) b. Knowing whether software is commercial or not isn't feasible, neither in Debian nor in most free software projects - we don't track people's employment status or history, nor do we check who finances upstream projects (the original projects that we integrate in our operating system). c. If upstream projects stop making available their code for fear of being in the scope of CRA and its financial consequences, system security will actually get worse rather than better. d. Having to get legal advice before giving a gift to society will discourage many developers, especially those without a company or other organisation supporting them.
Debian is well known for its security track record through practices of responsible disclosure and coordination with upstream developers and other Free Software projects. We aim to live up to the commitment made in the Debian Social Contract: "We will not hide problems." (3) a.The Free Software community has developed a fine-tuned, tried-and-tested system of responsible disclosure in case of security issues which will be overturned by the mandatory reporting to European authorities within 24 hours (Art. 11 CRA). b. Debian spends a lot of volunteering time on security issues, provides quick security updates and works closely together with upstream projects and in coordination with other vendors. To protect its users, Debian regularly participates in limited embargos to coordinate fixes to security issues so that all other major Linux distributions can also have a complete fix when the vulnerability is disclosed. c. Security issue tracking and remediation is intentionally decentralized and distributed. The reporting of security issues to ENISA and the intended propagation to other authorities and national administrations would collect all software vulnerabilities in one place. This greatly increases the risk of leaking information about vulnerabilities to threat actors, representing a threat for all the users around the world, including European citizens. d. Activists use Debian (e.g. through derivatives such as Tails), among other reasons, to protect themselves from authoritarian governments; handing threat actors exploits they can use for oppression is against what Debian stands for. e. Developers and companies will downplay security issues because a "security" issue now comes with legal implications. Less clarity on what is truly a security issue will hurt users by leaving them vulnerable.
While proprietary software is developed behind closed doors, Free Software development is done in the open, transparent for everyone. To retain parity with proprietary software the open development process needs to be entirely exempt from CRA requirements, just as the development of software in private is. A "making available on the market" can only be considered after development is finished and the software is released.
Even if only "commercial activities" are in the scope of CRA, the Free Software community - and as a consequence, everybody - will lose a lot of small projects. CRA will force many small enterprises and most probably all self employed developers out of business because they simply cannot fulfill the requirements imposed by CRA. Debian and other Linux distributions depend on their work. If accepted as it is, CRA will undermine not only an established community but also a thriving market. CRA needs an exemption for small businesses and, at the very least, solo-entrepreneurs.

Information about the voting process: Debian uses the Condorcet method for voting. Simplistically, plain Condorcets method can be stated like so : "Consider all possible two-way races between candidates. The Condorcet winner, if there is one, is the one candidate who can beat each other candidate in a two-way race with that candidate." The problem is that in complex elections, there may well be a circular relationship in which A beats B, B beats C, and C beats A. Most of the variations on Condorcet use various means of resolving the tie. Debian's variation is spelled out in the constitution, specifically, A.5(3) Sources: (1) CRA proposals and links & PLD proposals and links (2) Debian Social Contract No. 2, 3, and 4 (3) Debian Constitution

Review: Wintersmith, by Terry Pratchett

Series:	Discworld #35
Publisher:	Clarion Books
Copyright:	2006
Printing:	2007
ISBN:	0-06-089033-9
Format:	Mass market
Pages:	450

Wintersmith is the 35th Discworld novel and the 3rd Tiffany Aching novel. You could probably start here, since understanding the backstory isn't vital for following the plot, but I'm not sure why you would. Tiffany is now training with Miss Treason, a 113-year-old witch who is quite different in her approach from Miss Level, Tiffany's mentor in A Hat Full of Sky. Miss Level was the unassuming and constantly helpful glue that held the neighborhood together. Miss Treason is the judge; her neighbors are scared of her and proud of being scared of her, since that means they have a proper witch who can see into their heads and sort out their problems. On the surface, they're quite different; part of the story of this book is Tiffany learning to see the similarities. First, though, Miss Treason rushes Tiffany to a strange midnight Morris Dance, without any explanation. The Morris Dance usually celebrates the coming of spring and is at the center of a village party, so Tiffany is quite confused by seeing it danced on a dark and windy night in late autumn. But there is a hole in the dance where the Fool normally is, and Tiffany can't keep herself from joining it. This proves to be a mistake. That space was left for someone very different from Tiffany, and now she's entangled herself in deep magic that she doesn't understand. This is another Pratchett novel where the main storyline didn't do much for me. All the trouble stems from Miss Treason being maddeningly opaque, and while she did warn Tiffany, she did so in that way that guarantees a protagonist of a middle-grade novel will ignore. The Wintersmith is a boring, one-note quasi-villain, and the plot mainly revolves around elemental powers being dumber than a sack of hammers. The one thing I will say about the main plot is that the magic Tiffany danced into is entangled with courtship and romance, Tiffany turns thirteen over the course of this book, and yet this is not weird and uncomfortable reading the way it would be in the hands of many other authors. Pratchett has a keen eye for the age range that he's targeting. The first awareness that there is such a thing as romance that might be relevant to oneself pairs nicely with the Wintersmith's utter confusion at how Tiffany's intrusion unbalanced his dance. This is a very specific age and experience that I think a lot of authors would shy away from, particularly with a female protagonist, and I thought Pratchett handled it adroitly. I personally found the Wintersmith's awkward courting tedious and annoying, but that's more about me than about the book. As with A Hat Full of Sky, though, everything other than the main plot was great. It is becoming obvious how much Tiffany and Granny Weatherwax have in common, and that Granny Weatherwax recognizes this and is training Tiffany herself. This is high-quality coming-of-age material, not in the traditional fantasy sense of chosen ones and map explorations, but in the sense of slowly-developing empathy and understanding of people who think differently than you do. Tiffany, like Granny Weatherwax, has very little patience with nonsense, and her irritation with stupidity is one of her best characteristics. But she's learning how to blunt it long enough to pay attention, and to understand how people she doesn't like can still be the right people for specific situations. I particularly loved how Granny carries on with a feud at the same time that Tiffany is learning to let go of one. It's not a contradiction or hypocrisy; it's a sign that Tiffany is entitled to her judgments and feelings, but has to learn how to keep them in their place and not let them take over. One of the great things about the Tiffany Aching books is that the villages are also characters. We don't see that much of the individual people, but one of the things Tiffany is learning is how to see the interpersonal dynamics and patterns of village life. Somehow the feelings of irritation and exasperation fade once you understand people's motives and see more sides to their character. There is a lot more Nanny Ogg in this book than there has been in the last few, and that reminded me of how much I love her character. She has a completely different approach than Granny Weatherwax, but it's just as effective in different ways. She's also the perfect witch to have around when you've stumbled into a stylized love story that you don't want to be a part of, and yet find oddly fascinating. It says something about the skill of Pratchett's characterization that I could enjoy a book this much while having no interest in the main plot. The Witches have always been great characters, but somehow they're even better when seen through Tiffany's perspective. Good stuff; if you liked any of the other Tiffany Aching books, you will like this as well. Followed by Making Money in publication order. The next Tiffany Aching novel is I Shall Wear Midnight. Rating: 8 out of 10

I'd planned to write some private mail on the subject of preparing and delivering conference talks. However, each time I try to write that mail, I've managed to somehow contrive to lose it. So I thought I'd try as a blog post instead, to break the curse. The first aspect I wanted to write about is the pre-planning phase, or, the bit where you decide to give a talk in the first place. But first a bit about me. I don't talk all that regularly. I think I'm averaging one talk a year. I don't consider myself to be a natural talk-giver: I don't particularly enjoy it and I still get quite nervous. So the first question is: why do it? One motivation is that you want to attend a particular conference, and presenting at it makes it much easier to get institutional support for doing so (i.e., travel and accommodation covered). At the moment, I've written some talk proposals for FOSDEM because I want to attend, and it increases my chances if I'm delivering a talk. Another reason, pertinent to academia, is you wish to have a paper published. Last year I attended a conference in Portland that I had a paper accepted to. A condition of the paper being accepted is you attend and do a presentation about it. Obviously, the presentation itself is a useful form of dissemination for your work, but the paper has the potential to reach more people. You may wish to promote what you're talking about: academic work, but perhaps a piece of open source software that would benefit from wider awareness, more adoption, more bug reports, testing, and patches. You may wish to support the venue. There are a some of small-scale conferences that I enjoy participating in which don't receive a lot of submissions and so I tend to send one or more in order to help make sure there are enough possible talks to keep the whole thing viable. Finally, you may wish to promote yourself: certainly, some Software Engineers I've met seem to spend as much time on talks and travelling as writing software. It's a good way to see a lot of the world, and might be a good way to get your name known and increase your employment prospects. I feel lucky I haven't had to rely on this.

Welcome to the November 2023 report from the Reproducible Builds project! In these reports we outline the most important things that we have been up to over the past month. As a rather rapid recap, whilst anyone may inspect the source code of free software for malicious flaws, almost all software is distributed to end users as pre-compiled binaries (more).

Reproducible Builds Summit 2023 Between October 31st and November 2nd, we held our seventh Reproducible Builds Summit in Hamburg, Germany! Amazingly, the agenda and all notes from all sessions are all online many thanks to everyone who wrote notes from the sessions. As a followup on one idea, started at the summit, Alexander Couzens and Holger Levsen started work on a cache (or tailored front-end) for the snapshot.debian.org service. The general idea is that, when rebuilding Debian, you do not actually need the whole ~140TB of data from snapshot.debian.org; rather, only a very small subset of the packages are ever used for for building. It turns out, for `amd64`, `arm64`, `armhf`, `i386`, `ppc64el`, `riscv64` and `s390` for Debian trixie, unstable and experimental, this is only around 500GB ie. less than 1%. Although the new service not yet ready for usage, it has already provided a promising outlook in this regard. More information is available on https://rebuilder-snapshot.debian.net and we hope that this service becomes usable in the coming weeks. The adjacent picture shows a sticky note authored by Jan-Benedict Glaw at the summit in Hamburg, confirming Holger Levsen s theory that rebuilding all Debian packages needs a very small subset of packages, the text states that 69,200 packages (in Debian sid) list 24,850 packages in their `.buildinfo` files, in 8,0200 variations. This little piece of paper was the beginning of rebuilder-snapshot and is a direct outcome of the summit! The Reproducible Builds team would like to thank our event sponsors who include Mullvad VPN, openSUSE, Debian, Software Freedom Conservancy, Allotropia and Aspiration Tech.

Beyond Trusting FOSS presentation at SeaGL On November 4th, Vagrant Cascadian presented Beyond Trusting FOSS at SeaGL in Seattle, WA in the United States. Founded in 2013, SeaGL is a free, grassroots technical summit dedicated to spreading awareness and knowledge about free source software, hardware and culture. The summary of Vagrant s talk mentions that it will:
[ ] introduce the concepts of Reproducible Builds, including best practices for developing and releasing software, the tools available to help diagnose issues, and touch on progress towards solving decades-old deeply pervasive fundamental security issues Learn how to verify and demonstrate trust, rather than simply hoping everything is OK!
Germane to the contents of the talk, the slides for Vagrant s talk can be built reproducibly, resulting in a PDF with a SHA1 of `cfde2f8a0b7e6ec9b85377eeac0661d728b70f34` when built on Debian bookworm and `c21fab273232c550ce822c4b0d9988e6c49aa2c3` on Debian sid at the time of writing.

Human Factors in Software Supply Chain Security Marcel Fourn , Dominik Wermke, Sascha Fahl and Yasemin Acar have published an article in a Special Issue of the IEEE s Security & Privacy magazine. Entitled A Viewpoint on Human Factors in Software Supply Chain Security: A Research Agenda, the paper justifies the need for reproducible builds to reach developers and end-users specifically, and furthermore points out some under-researched topics that we have seen mentioned in interviews. An author pre-print of the article is available in PDF form.

Community updates On our mailing list this month:

Julien Lepiller mentioned that they were interested in translating our website, and provided offered GNU Guix s translation framework (Weblate) as a potential model to emulate.

Bernhard M. Wiedemann posted a positive LibreOffice success story documenting that, after some work:
[ ] today I hold in my hands the first two bit-identical LibreOffice rpm packages. And this is the success I wanted to share with you all today [and] it makes me feel as if we can solve anything.

kpcyrd reported on their excellent results with making `esp32c3` microcontroller firmware reproducible with Rust, repro-env and Arch Linux:
I chose the `esp32c3` [board] because it has good Rust support from the `esp-rs` project, and you can get a dev board for about 6-8 . To document my build environment I used `repro-env` together with Arch Linux because its archive is very reliable and contains all the different Rust development tools I needed.

Separate to their work on LibreOffice however, Bernhard M. Wiedemann also requested assistance with a number of packages that so far refuse to build reproducibly. He writes that the common theme around them is that they use scheme or lisp to produce binaries with a `dump` command and hopes that someone may be able to help.

Finally, Fay Stegerman regrettably reports that she will no longer be able to work on Android reproducible builds nor update the Reproducible Builds community with the status of reproducibility within F-Droid.

openSUSE updates Bernhard M. Wiedemann has created a wiki page outlining an proposal to create a general-purpose Linux distribution which consists of 100% bit-reproducible packages albeit minus the embedded signature within RPM files. It would be based on openSUSE Tumbleweed or, if available, its Slowroll-variant. In addition, Bernhard posted another monthly update for his work elsewhere in openSUSE.

Reproducibility-related changes in Debian As recently reported in the most recent Debian Developer News, Paul Gevers has integrated a package s reproducibility status into the way Debian migrates packages into the next stable release. For the `amd64`, `arm64`, `i386` and `armhf` architectures, data is collected from the Reproducible Builds testing framework is collected by this migration software even though, at the time of writing, it neither causes nor migration bonuses nor blocks migration. Indeed, the information only results are visible on Britney s excuses as well as on individual packages pages on tracker.debian.org.

Ubuntu Launchpad now supports `.buildinfo` files Back in 2017, Steve Langasek filed a bug against Ubuntu s Launchpad code hosting platform to report that `.changes` files (artifacts of building Ubuntu and Debian packages) reference `.buildinfo` files that aren t actually exposed by Launchpad itself. This was causing issues when attempting to process `.changes` files with tools such as Lintian. However, it was noticed last month that, in early August of this year, Simon Quigley had resolved this issue, and `.buildinfo` files are now available from the Launchpad system.

PHP reproducibility updates There have been two updates from the PHP programming language this month. Firstly, the widely-deployed PHPUnit framework for the PHP programming language have recently released version 10.5.0, which introduces the inclusion of a `composer.lock` file, ensuring total reproducibility of the shipped binary file. Further details and the discussion that went into their particular implementation can be found on the associated GitHub pull request. In addition, the presentation Leveraging Nix in the PHP ecosystem has been given in late October at the PHP International Conference in Munich by Pol Dellaiera. While the video replay is not yet available, the (reproducible) presentation slides and speaker notes are available.

diffoscope changes diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes, including:

Improving DOS/MBR extraction by adding support for `7z`. [ ]

Adding a missing `RequiredToolNotFound` import. [ ]

As a UI/UX improvement, try and avoid printing an extended traceback if diffoscope runs out of memory. [ ]

Mark diffoscope as stable on PyPI.org. [ ]

Uploading version `252` to Debian unstable. [ ]

Website updates A huge number of notes were added to our website that were taken at our recent Reproducible Builds Summit held between October 31st and November 2nd in Hamburg, Germany. In particular, a big thanks to Arnout Engelen, Bernhard M. Wiedemann, Daan De Meyer, Evangelos Ribeiro Tzaras, Holger Levsen and Orhun Parmaks z. In addition to this, a number of other changes were made, including:

Chris Lamb migrated the website s homepage to a hero image [ ], improved the documentation related to `SOURCE_DATE_EPOCH` and CMake [ ], added iomart (ne Bytemark) and DigitalOcean to our sponsors page [ ] and dropped an unnecessary link on some horizontal navigation buttons [ ].

Holger Levsen also made a large number of notes pages from our 2022 summit in Venice [ ], migrated the website s syntax highlighter from [Pygments]https://pygments.org/() to Rouge [ ], fixed some grammar on our donate page [ ][ ][ ] and did a lot of updates to the Hamburg Summit s general information page [ ][ ].

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:

Bernhard M. Wiedemann:

`amber-cli` (date-related issue)

`bin86` (FTBFS-2038)

`buildah` (timestamp)

`colord` (CPU)

`google-noto-fonts` (file modification issue)

`grub2` (directory-related metadata)

`guile-fibers` (parallelism issue)

`guile-newt` (parallelism issue)

`gutenprint` (embedded date/hostname)

`hub` (random build path)

`ipxe` (nondeterministic behavoiour)

`joker` / `joker`

`kopete` (undefined behaviour)

`kraft` (embedde hostname)

`libcamera` (signature)

`libguestfs` (embeds build host file)

`llvm` (toolchain/Rust-related issue)

`nfdump` (date-related issue)

`ovmf` (unknown cause)

`quazip` (missing fonts)

`rdflib` (nondeterminstic behaviour)

`rpm` (toolchain)

`tigervnc` (embedded an RSA signature)

`whatsie` (date-related issue)

`xen` (time-related issue)

Cathy Hu:

`policycoreutils` (sort-related issue)

Chris Lamb:

#1055919 filed against `python-ansible-pygments`.

#1055920 filed against `bidict`.

#1056117 filed against `meson`.

#1056118 filed against `radsecproxy`.

#1056119 filed against `taffybar`.

#1056398 filed against `php-doc`.

#1056571 filed against `pelican`.

#1056572 filed against `maildir-utils`.

#1056573 filed against `openmrac-data`.

#1056649 filed against `vectorscan`.

Vagrant Cascadian:

#1055969 filed against `kuttypy`.

Reproducibility 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 October, a number of changes were made by Holger Levsen:

Debian-related changes:

Track packages marked as `Priority: important` in a new package set. [ ][ ]

Stop scheduling packages that fail to build from source in bookworm [ ] and bullseye. [ ].

Add old releases dashboard link in web navigation. [ ]

Permit re-run of the `pool_buildinfos` script to be re-run for a specific year. [ ]

Grant jbglaw access to the `osuosl4` node [ ][ ] along with lynxis [ ].

Increase RAM on the `amd64` Ionos builders from 48 GiB to 64 GiB; thanks IONOS! [ ]

Move buster to archived suites. [ ][ ]

Reduce the number of `arm64` architecture workers from 24 to 16 in order to improve stability [ ], reduce the workers for `amd64` from 32 to 28 and, for `i386`, reduce from 12 down to 8 [ ].

Show the entire build history of each Debian package. [ ]

Stop scheduling already tested package/version combinations in Debian bookworm. [ ]

Snapshot service for rebuilders

Add an HTTP-based API endpoint. [ ][ ]

Add a Gunicorn instance to serve the HTTP API. [ ]

Add an NGINX config [ ][ ][ ][ ]

System-health:

Detect failures due to HTTP 503 Service Unavailable errors. [ ]

Detect failures to update package sets. [ ]

Detect unmet dependencies. (This usually occurs with builds of Debian `live-build`.) [ ]

Misc-related changes:

do install systemd-ommd on jenkins. [ ]

fix harmless typo in squid.conf for codethink04. [ ]

fixup: reproducible Debian: add gunicorn service to serve /api for rebuilder-snapshot.d.o. [ ]

Increase codethink04 s Squid `cache_dir` size setting to 16 GiB. [ ]

Don t install `systemd-oomd` as it unfortunately kills `sshd` [ ]

Use `debootstrap` from backports when commisioning nodes. [ ]

Add the `live_build_debian_stretch_gnome`, `debsums-tests_buster` and `debsums-tests_buster` jobs to the zombie list. [ ][ ]

Run `jekyll build` with the `--watch` argument when building the Reproducible Builds website. [ ]

Misc node maintenance. [ ][ ][ ]

Other changes were made as well, however, including Mattia Rizzolo fixing `rc.local` s Bash syntax so it can actually run [ ], commenting away some file cleanup code that is (potentially) deleting too much [ ] and fixing the `html_brekages` page for Debian package builds [ ]. Finally, diagnosed and submitted a patch to add a `AddEncoding gzip .gz` line to the tests.reproducible-builds.org Apache configuration so that Gzip files aren t re-compressed as Gzip which some clients can t deal with (as well as being a waste of time). [ ]

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:

IRC: `#reproducible-builds` on `irc.oftc.net`.

Mailing list: `rb-general@lists.reproducible-builds.org`

Mastodon: @reproducible_builds

Twitter: @ReproBuilds

Hello from a snowy Montr al! My life has been pretty busy lately¹ so please forgive this late report. On November 19th, our local Debian User Group met at Montreal's most prominent hackerspace, Foulab. We've been there a few times already, but since our last visit, Foulab has had some membership/financial troubles. Happy to say things are going well again and a new team has taken over the space. This meetup wasn't the most productive day for me (something about being exhausted apparently makes it hard to concentrate), but other people did a bunch of interesting stuff :)

Kienan & Gabriel worked on the libinfluxdb-http-perl package (now in Sid!), which is needed for smokeping.
J r me worked on updating JRuby to the latest upstream version.
I failed to update monitoring-plugins-systemd to the latest upstream version. It seems the entire test suite has been re-written and I couldn't make it work in sbuild...
Tiago and Tassia worked on the Debian Contributors website. More specifically, they added a DSA domains data source and created a scheduler on dcf.debian.net to make daily updates on the data sources in the dc-sources repository.
Michael worked on the 2024 NorthSec badge.
Gerard worked on debugging his broken AirGradient board.

Pictures Here are a bunch of pictures I took! Foulab is always a great place to snap quirky things :) A sign on a whiteboard that says 'Bienvenue aux laboratoires qui rends fou'

A sign on a whiteboard that says 'Bienvenue aux laboratoires qui rends fou'

The entrance of the bio-hacking house, with a list of rules

An exploded keyboard with a 'Press F1 to continue' sign

More busy than the typical end of semester rush... At work, we are currently renegotiating our collective bargaining agreement and things aren't going so well. We went on strike for a few days already and we're planning on another 7 days starting on Friday 8th.

Due to the current state of affairs in Israel, who were to host DebConf24, the DebConf committee has decided to renew calls for bids to host DebConf24 at another venue and location. The DebConf committee would like to express our sincere appreciation for the DebConf Israeli team, and the work they've done over several years. However, given the uncertainty about the situation, we regret that it will most likely not be possible to hold DebConf in Israel. As we ask for submissions for new host locations we ask that you please review and understand the details and requirements for a bid submission to host the Debian Developer Conference. Please review the template for a DebConf bid for guidelines on how to sumbit a proper bid. To submit a bid, please create the appropriate page(s) under DebConf Wiki Bids, and add it to the "Bids" section in the main DebConf 24 page. There isn't very much time to make a decision. We need bids by the end of November in order to make a decision by the end of the year. After your submission is completed please send us a notification at debconf-team@lists.debian.org to let us know that your bid submission is ready for review. We also suggest hanging out in our IRC chat room #debconf-team. Given this short deadline, we understand that bids won't be as complete as they would usually be. Do the best you can in the time available. Bids will be evaluated according to The Priority List. You can get in contact with the DebConf team by email to debconf-team@lists.debian.org, or via the #debconf-team IRC channel on OFTC or via our Matrix Channel. Thank you, The Debian Debconf Committee

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.

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.

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/.

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 :) .

All in all, a nice event by sflc.in :)

I have made a new helper for producing Debian packages called debputy. Today, I uploaded it to Debian unstable for the first time. This enables others to migrate their package build using dh +debputy rather than the classic dh. Eventually, I hope to remove dh entirely from this equation, so you only need debputy. But for now, debputy still leverages dh support for managing upstream build systems. The debputy tool takes a radicially different approach to packaging compared to our existing packaging methods by using a single highlevel manifest instead of all the debian/install (etc.) and no hook targets in debian/rules. Here are some of the things that debputy can do or does:

debputy can perform installation similar to dh_install, dh_installdocs (etc.) plus a bit of the dh-exec support. Notably, debputy supports install /usr/bin/foo into foo and install everything else in /usr/bin into foo-utils without you having to resort to weird tricks. With debhelper, this would require dh-exec s => /usr/bin/foo operator.
debputy can assign mode to files without needing hooks and static file ownership can be assigned without resorting to fakeroot. If you request Rules-Requires-Root: no, debputy will assemble the deb without using fakeroot. The fragileness of fakeroot may some day just be a horror story we tell our unruly children that they do not really believe is true.
debputy defaults to all scripts with a #! /bin/tool or #! /usr/bin/tool to have mode 0755 (a+x) unless they are placed in directories known not to have executable files (such as the perl module dirs). As an example, scripts in the examples directory may now get an automatic executable bit if they have a proper #!-line for /usr/bin or /bin.
debputy supports the default flow of 48 debhelper tools. If you are using pure dh $@ with no sequence add-ons and no hook targets in debian/rules (or only hook targets for the upstream side), odds are that debputy got your needs covered.

There are also some features that debputy does not support at the moment:

Almost any debhelper sequence add-on. The debputy tool comes with a migration tool that will auto-detect any unsupported dh add-on from Build-Depends and will flag them as potential problematic. The migration tool works from an list of approved add-ons. Note that manually activated add-ons via dh $@ with are not detected.
Anything that installs or recently installed into /lib or another /usr-merged location. My life is too short to be directly involved in the /usr-merge transition. This means no udev and no systemd unit support at the moment (note tmpfiles and sysusers is supported). For the systemd side, I am also contemplating a different model for how to deal with services. Even without the /usr-merge transition, these would not have been supported. The migration tool will detect problematic file in the debian directory immediately and debputy will detect upstream provided systemd unit files at build time.
There is also no support for packager provided maintscript files at this time. If you have your own maintscripts, then you will not be able to migrate. The migration tool detects the debhelper based path and warns you (such as debian/postinst).
Additionally, if you need special cases in tools (such as perl-base dependency with dh_perl) or rely on dh_strip-nondeterminsm for reproducibility, then you cannot or is advised not to migrate at this time.

There are all limitations of the current work in progress. I hope to resolve them all in due time.

Trying debputy With the limitations aside, lets talk about how you would go about migrating a package:

# Assuming here you have already run: apt install dh-debputy
$ git clone https://salsa.debian.org/rra/kstart
[...]
$ cd kstart
# Add a Build-Dependency on dh-sequence-debputy
$ perl -n -i -e \
   'print; print " dh-sequence-debputy,\n" if m/debhelper-compat/;' \
    debian/control
$ debputy migrate-from-dh --apply-changes
debputy: info: Loading plugin debputy (version: archive/debian/4.3-1) ...
debputy: info: Verifying the generating manifest
debputy: info: Updated manifest debian/debputy.manifest
debputy: info: Removals:
debputy: info:   rm -f "./debian/docs"
debputy: info:   rm -f "./debian/examples"
debputy: info: Migrations performed successfully
debputy: info: Remember to validate the resulting binary packages after rebuilding with debputy
$ cat debian/debputy.manifest 
manifest-version: '0.1'
installations:
- install-docs:
    sources:
    - NEWS
    - README
    - TODO
- install-examples:
    source: examples/krenew-agent
$ git add debian/debputy.manifest
$ git commit --signoff -am"Migrate to debputy"
# Run build tool of choice to verify the output.

This is of course a specific example that works out of the box. If you were to try this on debianutils (from git), the output would look something like this:

$ debputy migrate-from-dh
debputy: info: Loading plugin debputy (version: 5.13-13-g9836721) ...
debputy: error: Unable to migrate automatically due to missing features in debputy.
  * The "debian/triggers" debhelper config file (used by dh_installdeb is currently not supported by debputy.
Use --acceptable-migration-issues=[...] to convert this into a warning [...]

And indeed, debianutils requires at least 4 debhelper features beyond what debputy can support at the moment (all related to maintscripts and triggers).

Rapid feedback Rapid feedback cycles are important for keeping developers engaged in their work. The debputy tool provides the following features to enable rapid feedback.

Immediate manifest validation It would be absolutely horrible if you had to do a full-rebuild only to realize you got the manifest syntax wrong. Therefore, debputy has a check-manifest command that checks the manifest for syntactical and semantic issues.

$ cat debian/debputy.manifest
manifest-version: '0.1'
installations:
- install-docs:
    sources:
    - GETTING-STARTED-WITH-dh-debputy.md
    - MANIFEST-FORMAT.md
    - MIGRATING-A-DH-PLUGIN.md
$ debputy check-manifest
debputy: info: Loading plugin debputy (version: 0.1.7-1-gf34bd66) ...
debputy: info: No errors detected.
$ cat <<EOF >> debian/debputy.manifest
- install:
    sourced: foo
    as: usr/bin/foo
EOF
# Did I typo anything?
$ debputy check-manifest
debputy: info: Loading plugin debputy (version: 0.1.7-2-g4ef8c2f) ...
debputy: warning: Possible typo: The key "sourced" at "installations[1].install" should probably have been 'source'
debputy: error: Unknown keys " 'sourced' " at installations[1].install".  Keys that could be used here are: sources, when, dest-dir, source, into.
debputy: info: Loading plugin debputy (version: 0.1.7-2-g4ef8c2f) ...
$ sed -i s/sourced:/source:/ debian/debputy.manifest
$ debputy check-manifest
debputy: info: Loading plugin debputy (version: 0.1.7-2-g4ef8c2f) ...
debputy: info: No errors detected.

The debputy check-manifest command is limited to the manifest itself and does not warn about foo not existing as it could be produced as apart of the upstream build system. Therefore, there are still issues that can only be detected at package build time. But where debputy can reliably give you immediate feedback, it will do so.

Idempotence: Clean re-runs of dh_debputy without clean/rebuild If you read the fine print of many debhelper commands, you may see the following note their manpage:
This command is not idempotent. dh_prep(1) should be called between invocations of this command Manpage of an anonymous debhelper tool
What this usually means, is that if you run the command twice, you will get its maintscript change (etc.) twice in the final deb. This fits into our single-use clean throw-away chroot builds on the buildds and CI as well as dpkg-buildpackage s no-clean (-nc) option. Single-use throw-away chroots are not very helpful for debugging though, so I rarely use them when doing the majority of my packaging work as I do not want to wait for the chroot initialization (including installing of build-depends). But even then, I have found that dpkg-buildpackage -nc has been useless for me in many cases as I am stuck between two options:

With -nc, you often still interact with the upstream build system. As an example, debhelper will do a dh_prep followed by dh_auto_install, so now we are waiting for upstream s install target to run again. What should have taken seconds now easily take 0.5-1 minute extra per attempt.

If you want to by-pass this, you have to manually call the helpers needed (in correct order) and every run accumulates cruft from previous runs to the point that cruft drowns out the actual change you want to see. Also, I am rarely in the mood to play human dh, when I am debugging an issue that I failed to fix in my first, second and third try.

As you can probably tell, neither option has worked that well for me. But with dh_debputy, I have made it a goal that it will not self-taint the final output. If dh_debputy fails, you should be able to tweak the manifest and re-run dh_debputy with the same arguments.

No waiting for dpkg-buildpackage -nc nor anything implied by that.

No self-tainting of the final deb. The result you get, is the result you would have gotten if the previous dh_debputy run never happened.

Because dh_debputy produces the final result, I do not have to run multiple tools in the right order.

Obviously, this is currently a lot easier, because debputy is not involved in the upstream build system at all. If this feature is useful to you, please do let me know and I will try to preserve it as debputy progresses in features.

Packager provided files On a different topic, have you ever wondered what kind of files you can place into the debian directory that debhelper automatically picks up or reacts too? I do not have an answer to that beyond it is over 80 files and that as the maintainer of debhelper, I am not willing to manually maintain such a list manually. However, I do know what the answer is in debputy, because I can just ask debputy:

$ debputy plugin list packager-provided-files
+-----------------------------+---------------------------------------------[...]
  Stem                          Installed As                                [...]
+-----------------------------+---------------------------------------------[...]
  NEWS                          /usr/share/doc/ name /NEWS.Debian           [...]
  README.Debian                 /usr/share/doc/ name /README.Debian         [...]
  TODO                          /usr/share/doc/ name /TODO.Debian           [...]
  bug-control                   /usr/share/bug/ name /control               [...]
  bug-presubj                   /usr/share/bug/ name /presubj               [...]
  bug-script                    /usr/share/bug/ name /script                [...]
  changelog                     /usr/share/doc/ name /changelog.Debian      [...]
  copyright                     /usr/share/doc/ name /copyright             [...]
[...]

This will list all file types (Stem column) that debputy knows about and it accounts for any plugin that debputy can find. Note to be deterministic, debputy will not auto-load plugins that have not been explicitly requested during package builds. So this list could list files that are available but not active for your current package. Note the output is not intended to be machine readable. That may come in later version. Feel free to chime in if you have a concrete use-case.

Take it for a spin As I started this blog post with, debputy is now available in unstable. I hope you will take it for a spin on some of your simpler packages and provide feedback on it. For documentation, please have a look at:

GETTING-STARTED-WITH-dh-debputy.md (how-to guide)

MANIFEST-FORMAT.md (reference documentation)

Thanks for considering PS: My deepest respect to the fakeroot maintainers. That game of whack-a-mole is not something I would have been willing to maintain. I think fakeroot is like the Python GIL in the sense that it has been important in getting Debian to where it is today. But at the same time, I feel it is time to let go of the crutch and find a proper solution.

I m one of the few folks left who run and maintain mail servers. Recently I had major troubles receiving mails from the mail servers used by a bank, and when asking my favourite search engine, I m clearly not the only one who ran into such an issue. Actually, I should have checked off the issue and not become a customer at that bank, but the tech nerd in me couldn t resist getting to the bottom of the problem. Since I got it working and this might be useful for others, here we are. :) I was trying to get an online banking account set up, but the corresponding account creation mail didn t arrive me, at all. Looking at my mail server logs, my postfix mail server didn t accept the mail due to:

postfix/smtpd[3319640]: warning: TLS library problem: error:1417A0C1:SSL routines:tls_post_process_client_hello:no shared cipher:../ssl/statem/statem_srvr.c:2283:
postfix/smtpd[3319640]: lost connection after STARTTLS from mx01.arz.at[193.110.182.61]

Huh, what s going on here?! Let s increase the TLS loglevel (setting smtpd_tls_loglevel = 2) and retry. But how can I retry receiving yet another mail? Luckily, on the registration website of the bank there was a URL available, that let me request a one-time password. This triggered another mail, so I did that and managed to grab this in the logs:

postfix/smtpd[3320018]: initializing the server-side TLS engine
postfix/tlsmgr[3320020]: open smtpd TLS cache btree:/var/lib/postfix/smtpd_scache
postfix/tlsmgr[3320020]: tlsmgr_cache_run_event: start TLS smtpd session cache cleanup
postfix/smtpd[3320018]: connect from mx01.arz.at[193.110.182.61]
postfix/smtpd[3320018]: setting up TLS connection from mx01.arz.at[193.110.182.61]
postfix/smtpd[3320018]: mx01.arz.at[193.110.182.61]: TLS cipher list "aNULL:-aNULL:HIGH:MEDIUM:+RC4:@STRENGTH"
postfix/smtpd[3320018]: SSL_accept:before SSL initialization
postfix/smtpd[3320018]: SSL_accept:before SSL initialization
postfix/smtpd[3320018]: SSL3 alert write:fatal:handshake failure
postfix/smtpd[3320018]: SSL_accept:error in error
postfix/smtpd[3320018]: SSL_accept error from mx01.arz.at[193.110.182.61]: -1
postfix/smtpd[3320018]: warning: TLS library problem: error:1417A0C1:SSL routines:tls_post_process_client_hello:no shared cipher:../ssl/statem/statem_srvr.c:2283:
postfix/smtpd[3320018]: lost connection after STARTTLS from mx01.arz.at[193.110.182.61]
postfix/smtpd[3320018]: disconnect from mx01.arz.at[193.110.182.61] ehlo=1 starttls=0/1 commands=1/2
postfix/smtpd[3320018]: connect from mx01.arz.at[193.110.182.61]
postfix/smtpd[3320018]: disconnect from mx01.arz.at[193.110.182.61] ehlo=1 quit=1 commands=2

Ok, so this TLS cipher list aNULL:-aNULL:HIGH:MEDIUM:+RC4:@STRENGTH looked like the tls_medium_cipherlist setting in postfix, but which ciphers might we expect? Let s see what their SMTP server would speak to us:

% testssl --cipher-per-proto -t=smtp mx01.arz.at:25
[...]
Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
SSLv2
SSLv3
TLS 1
TLS 1.1
TLS 1.2
 xc030   ECDHE-RSA-AES256-GCM-SHA384       ECDH 256   AESGCM      256      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
 xc028   ECDHE-RSA-AES256-SHA384           ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
 xc014   ECDHE-RSA-AES256-SHA              ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 x9d     AES256-GCM-SHA384                 RSA        AESGCM      256      TLS_RSA_WITH_AES_256_GCM_SHA384
 x3d     AES256-SHA256                     RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA256
 x35     AES256-SHA                        RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA
 xc02f   ECDHE-RSA-AES128-GCM-SHA256       ECDH 256   AESGCM      128      TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
 xc027   ECDHE-RSA-AES128-SHA256           ECDH 256   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
 xc013   ECDHE-RSA-AES128-SHA              ECDH 256   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 x9c     AES128-GCM-SHA256                 RSA        AESGCM      128      TLS_RSA_WITH_AES_128_GCM_SHA256
 x3c     AES128-SHA256                     RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA256
 x2f     AES128-SHA                        RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA
TLS 1.3

Looks like a very small subset of ciphers, and they don t seem to be talking TLS v1.3 at all? Not great. :( A nice web service to verify the situation from another point of view is checktls, which also confirmed this:

[000.705] 	<-- 	220 2.0.0 Ready to start TLS
[000.705] 		STARTTLS command works on this server
[001.260] 		Connection converted to SSL
		SSLVersion in use: TLSv1_2
		Cipher in use: ECDHE-RSA-AES256-GCM-SHA384
		Perfect Forward Secrecy: yes
		Session Algorithm in use: Curve P-256 DHE(256 bits)
		Certificate #1 of 3 (sent by MX):
		Cert VALIDATED: ok
		Cert Hostname VERIFIED (mx01.arz.at = *.arz.at   DNS:*.arz.at   DNS:arz.at)
[...]
[001.517] 		TLS successfully started on this server

I got distracted by some other work, and when coming back to this problem, the one-time password procedure no longer worked, as the password reset URL was no longer valid. :( I managed to find the underlying URL, and with some web developer tools tinkering I could still use the website to let me trigger sending further one-time password mails, phew. Let s continue, so my mail server was running Debian/bullseye with postfix v3.5.18-0+deb11u1 and openssl v1.1.1n-0+deb11u5, let s see what it offers:

% testssl --cipher-per-proto -t=smtp mail.example.com:25
[...]
Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
SSLv2
SSLv3
TLS 1
 xc00a   ECDHE-ECDSA-AES256-SHA            ECDH 253   AES         256      TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 xc009   ECDHE-ECDSA-AES128-SHA            ECDH 253   AES         128      TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
TLS 1.1
 xc00a   ECDHE-ECDSA-AES256-SHA            ECDH 253   AES         256      TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 xc009   ECDHE-ECDSA-AES128-SHA            ECDH 253   AES         128      TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
TLS 1.2
 xc02c   ECDHE-ECDSA-AES256-GCM-SHA384     ECDH 253   AESGCM      256      TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
 xc024   ECDHE-ECDSA-AES256-SHA384         ECDH 253   AES         256      TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
 xc00a   ECDHE-ECDSA-AES256-SHA            ECDH 253   AES         256      TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
 xcca9   ECDHE-ECDSA-CHACHA20-POLY1305     ECDH 253   ChaCha20    256      TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
 xc0af   ECDHE-ECDSA-AES256-CCM8           ECDH 253   AESCCM8     256      TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8
 xc0ad   ECDHE-ECDSA-AES256-CCM            ECDH 253   AESCCM      256      TLS_ECDHE_ECDSA_WITH_AES_256_CCM
 xc073   ECDHE-ECDSA-CAMELLIA256-SHA384    ECDH 253   Camellia    256      TLS_ECDHE_ECDSA_WITH_CAMELLIA_256_CBC_SHA384
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 xa7     ADH-AES256-GCM-SHA384             DH 2048    AESGCM      256      TLS_DH_anon_WITH_AES_256_GCM_SHA384
 x6d     ADH-AES256-SHA256                 DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA256
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 xc5     ADH-CAMELLIA256-SHA256            DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA256
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 xc05d   ECDHE-ECDSA-ARIA256-GCM-SHA384    ECDH 253   ARIAGCM     256      TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384
 xc02b   ECDHE-ECDSA-AES128-GCM-SHA256     ECDH 253   AESGCM      128      TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
 xc023   ECDHE-ECDSA-AES128-SHA256         ECDH 253   AES         128      TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
 xc009   ECDHE-ECDSA-AES128-SHA            ECDH 253   AES         128      TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
 xc0ae   ECDHE-ECDSA-AES128-CCM8           ECDH 253   AESCCM8     128      TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8
 xc0ac   ECDHE-ECDSA-AES128-CCM            ECDH 253   AESCCM      128      TLS_ECDHE_ECDSA_WITH_AES_128_CCM
 xc072   ECDHE-ECDSA-CAMELLIA128-SHA256    ECDH 253   Camellia    128      TLS_ECDHE_ECDSA_WITH_CAMELLIA_128_CBC_SHA256
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 xa6     ADH-AES128-GCM-SHA256             DH 2048    AESGCM      128      TLS_DH_anon_WITH_AES_128_GCM_SHA256
 x6c     ADH-AES128-SHA256                 DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA256
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 xbf     ADH-CAMELLIA128-SHA256            DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA256
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
 xc05c   ECDHE-ECDSA-ARIA128-GCM-SHA256    ECDH 253   ARIAGCM     128      TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256
TLS 1.3
 x1302   TLS_AES_256_GCM_SHA384            ECDH 253   AESGCM      256      TLS_AES_256_GCM_SHA384
 x1303   TLS_CHACHA20_POLY1305_SHA256      ECDH 253   ChaCha20    256      TLS_CHACHA20_POLY1305_SHA256
 x1301   TLS_AES_128_GCM_SHA256            ECDH 253   AESGCM      128      TLS_AES_128_GCM_SHA256

Not so bad, but sadly no overlap with any of the ciphers that mx01.arz.at offers. What about disabling STARTTLS for the mx01.arz.at (+ mx02.arz.at being another one used by the relevant domain) mail servers when talking to mine? Let s try that:

% sudo postconf -nf smtpd_discard_ehlo_keyword_address_maps
smtpd_discard_ehlo_keyword_address_maps =
    hash:/etc/postfix/smtpd_discard_ehlo_keywords
% cat /etc/postfix/smtpd_discard_ehlo_keywords
# *disable* starttls for mx01.arz.at / mx02.arz.at:
193.110.182.61 starttls
193.110.182.62 starttls

But the remote mail server doesn t seem to send mails without TLS:

postfix/smtpd[4151799]: connect from mx01.arz.at[193.110.182.61]
postfix/smtpd[4151799]: discarding EHLO keywords: STARTTLS
postfix/smtpd[4151799]: disconnect from mx01.arz.at[193.110.182.61] ehlo=1 quit=1 commands=2

Let s verify this further, but without fiddling with the main mail server too much. We can add a dedicated service to postfix (see serverfault), and run it in verbose mode, to get more detailled logging:

% sudo postconf -Mf
[...]
10025      inet  n       -       -       -       -       smtpd
    -o syslog_name=postfix/smtpd/badstarttls
    -o smtpd_tls_security_level=none
    -o smtpd_helo_required=yes
    -o smtpd_helo_restrictions=pcre:/etc/postfix/helo_badstarttls_allow,reject
    -v
[...]
% cat /etc/postfix/helo_badstarttls_allow
/mx01.arz.at/ OK
/mx02.arz.at/ OK
/193.110.182.61/ OK
/193.110.182.62/ OK

We redirect the traffic from mx01.arz.at + mx02.arz.at towards our new postfix service, listening on port 10025:

% sudo iptables -t nat -A PREROUTING -p tcp -s 193.110.182.61 --dport 25 -j REDIRECT --to-port 10025
% sudo iptables -t nat -A PREROUTING -p tcp -s 193.110.182.62 --dport 25 -j REDIRECT --to-port 10025

With this setup we get very detailed logging, and it seems to confirm our suspicion that the mail server doesn t want to talk unencrypted with us:

[...]
postfix/smtpd/badstarttls/smtpd[3491900]: connect from mx01.arz.at[193.110.182.61]
[...]
postfix/smtpd/badstarttls/smtpd[3491901]: disconnect from mx01.arz.at[193.110.182.61] ehlo=1 quit=1 commands=2
postfix/smtpd/badstarttls/smtpd[3491901]: master_notify: status 1
postfix/smtpd/badstarttls/smtpd[3491901]: connection closed
[...]

Let s step back and revert those changes, back to our original postfix setup. Might the problem be related to our Let s Encrypt certificate? Let s see what we have:

% echo QUIT   openssl s_client -connect mail.example.com:25 -starttls
[...]
issuer=C = US, O = Let's Encrypt, CN = R3
---
No client certificate CA names sent
Peer signing digest: SHA384
Peer signature type: ECDSA
Server Temp Key: X25519, 253 bits
---
SSL handshake has read 4455 bytes and written 427 bytes
Verification: OK
---
New, TLSv1.3, Cipher is TLS_AES_256_GCM_SHA384
Server public key is 384 bit
[...]

We have an ECDSA based certificate, what about switching to RSA instead? Thanks to the wonderful dehydrated, this is as easy as:

% echo KEY_ALGO=rsa > certs/mail.example.com/config
% ./dehydrated -c --domain mail.example.com --force
% sudo systemctl reload postfix

With switching to RSA type key we get:

% echo QUIT   openssl s_client -connect mail.example.com:25 -starttls smtp
CONNECTED(00000003)
[...]
issuer=C = US, O = Let's Encrypt, CN = R3
---
No client certificate CA names sent
Peer signing digest: SHA256
Peer signature type: RSA-PSS
Server Temp Key: X25519, 253 bits
---
SSL handshake has read 5295 bytes and written 427 bytes
Verification: OK
---
New, TLSv1.3, Cipher is TLS_AES_256_GCM_SHA384
Server public key is 4096 bit

Which ciphers do we offer now? Let s check:

% testssl --cipher-per-proto -t=smtp mail.example.com:25
[...]
Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
SSLv2
SSLv3
TLS 1
 xc014   ECDHE-RSA-AES256-SHA              ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 x39     DHE-RSA-AES256-SHA                DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA
 x88     DHE-RSA-CAMELLIA256-SHA           DH 2048    Camellia    256      TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 x35     AES256-SHA                        RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA
 x84     CAMELLIA256-SHA                   RSA        Camellia    256      TLS_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc013   ECDHE-RSA-AES128-SHA              ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 x33     DHE-RSA-AES128-SHA                DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA
 x9a     DHE-RSA-SEED-SHA                  DH 2048    SEED        128      TLS_DHE_RSA_WITH_SEED_CBC_SHA
 x45     DHE-RSA-CAMELLIA128-SHA           DH 2048    Camellia    128      TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
 x2f     AES128-SHA                        RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA
 x96     SEED-SHA                          RSA        SEED        128      TLS_RSA_WITH_SEED_CBC_SHA
 x41     CAMELLIA128-SHA                   RSA        Camellia    128      TLS_RSA_WITH_CAMELLIA_128_CBC_SHA
TLS 1.1
 xc014   ECDHE-RSA-AES256-SHA              ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 x39     DHE-RSA-AES256-SHA                DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA
 x88     DHE-RSA-CAMELLIA256-SHA           DH 2048    Camellia    256      TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 x35     AES256-SHA                        RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA
 x84     CAMELLIA256-SHA                   RSA        Camellia    256      TLS_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc013   ECDHE-RSA-AES128-SHA              ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 x33     DHE-RSA-AES128-SHA                DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA
 x9a     DHE-RSA-SEED-SHA                  DH 2048    SEED        128      TLS_DHE_RSA_WITH_SEED_CBC_SHA
 x45     DHE-RSA-CAMELLIA128-SHA           DH 2048    Camellia    128      TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
 x2f     AES128-SHA                        RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA
 x96     SEED-SHA                          RSA        SEED        128      TLS_RSA_WITH_SEED_CBC_SHA
 x41     CAMELLIA128-SHA                   RSA        Camellia    128      TLS_RSA_WITH_CAMELLIA_128_CBC_SHA
TLS 1.2
 xc030   ECDHE-RSA-AES256-GCM-SHA384       ECDH 253   AESGCM      256      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
 xc028   ECDHE-RSA-AES256-SHA384           ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
 xc014   ECDHE-RSA-AES256-SHA              ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 x9f     DHE-RSA-AES256-GCM-SHA384         DH 2048    AESGCM      256      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
 xcca8   ECDHE-RSA-CHACHA20-POLY1305       ECDH 253   ChaCha20    256      TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 xccaa   DHE-RSA-CHACHA20-POLY1305         DH 2048    ChaCha20    256      TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 xc0a3   DHE-RSA-AES256-CCM8               DH 2048    AESCCM8     256      TLS_DHE_RSA_WITH_AES_256_CCM_8
 xc09f   DHE-RSA-AES256-CCM                DH 2048    AESCCM      256      TLS_DHE_RSA_WITH_AES_256_CCM
 x6b     DHE-RSA-AES256-SHA256             DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
 x39     DHE-RSA-AES256-SHA                DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA
 xc077   ECDHE-RSA-CAMELLIA256-SHA384      ECDH 253   Camellia    256      TLS_ECDHE_RSA_WITH_CAMELLIA_256_CBC_SHA384
 xc4     DHE-RSA-CAMELLIA256-SHA256        DH 2048    Camellia    256      TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256
 x88     DHE-RSA-CAMELLIA256-SHA           DH 2048    Camellia    256      TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc019   AECDH-AES256-SHA                  ECDH 253   AES         256      TLS_ECDH_anon_WITH_AES_256_CBC_SHA
 xa7     ADH-AES256-GCM-SHA384             DH 2048    AESGCM      256      TLS_DH_anon_WITH_AES_256_GCM_SHA384
 x6d     ADH-AES256-SHA256                 DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA256
 x3a     ADH-AES256-SHA                    DH 2048    AES         256      TLS_DH_anon_WITH_AES_256_CBC_SHA
 xc5     ADH-CAMELLIA256-SHA256            DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA256
 x89     ADH-CAMELLIA256-SHA               DH 2048    Camellia    256      TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA
 x9d     AES256-GCM-SHA384                 RSA        AESGCM      256      TLS_RSA_WITH_AES_256_GCM_SHA384
 xc0a1   AES256-CCM8                       RSA        AESCCM8     256      TLS_RSA_WITH_AES_256_CCM_8
 xc09d   AES256-CCM                        RSA        AESCCM      256      TLS_RSA_WITH_AES_256_CCM
 x3d     AES256-SHA256                     RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA256
 x35     AES256-SHA                        RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA
 xc0     CAMELLIA256-SHA256                RSA        Camellia    256      TLS_RSA_WITH_CAMELLIA_256_CBC_SHA256
 x84     CAMELLIA256-SHA                   RSA        Camellia    256      TLS_RSA_WITH_CAMELLIA_256_CBC_SHA
 xc051   ARIA256-GCM-SHA384                RSA        ARIAGCM     256      TLS_RSA_WITH_ARIA_256_GCM_SHA384
 xc053   DHE-RSA-ARIA256-GCM-SHA384        DH 2048    ARIAGCM     256      TLS_DHE_RSA_WITH_ARIA_256_GCM_SHA384
 xc061   ECDHE-ARIA256-GCM-SHA384          ECDH 253   ARIAGCM     256      TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384
 xc02f   ECDHE-RSA-AES128-GCM-SHA256       ECDH 253   AESGCM      128      TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
 xc027   ECDHE-RSA-AES128-SHA256           ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
 xc013   ECDHE-RSA-AES128-SHA              ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 x9e     DHE-RSA-AES128-GCM-SHA256         DH 2048    AESGCM      128      TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
 xc0a2   DHE-RSA-AES128-CCM8               DH 2048    AESCCM8     128      TLS_DHE_RSA_WITH_AES_128_CCM_8
 xc09e   DHE-RSA-AES128-CCM                DH 2048    AESCCM      128      TLS_DHE_RSA_WITH_AES_128_CCM
 xc0a0   AES128-CCM8                       RSA        AESCCM8     128      TLS_RSA_WITH_AES_128_CCM_8
 xc09c   AES128-CCM                        RSA        AESCCM      128      TLS_RSA_WITH_AES_128_CCM
 x67     DHE-RSA-AES128-SHA256             DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
 x33     DHE-RSA-AES128-SHA                DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA
 xc076   ECDHE-RSA-CAMELLIA128-SHA256      ECDH 253   Camellia    128      TLS_ECDHE_RSA_WITH_CAMELLIA_128_CBC_SHA256
 xbe     DHE-RSA-CAMELLIA128-SHA256        DH 2048    Camellia    128      TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256
 x9a     DHE-RSA-SEED-SHA                  DH 2048    SEED        128      TLS_DHE_RSA_WITH_SEED_CBC_SHA
 x45     DHE-RSA-CAMELLIA128-SHA           DH 2048    Camellia    128      TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA
 xc018   AECDH-AES128-SHA                  ECDH 253   AES         128      TLS_ECDH_anon_WITH_AES_128_CBC_SHA
 xa6     ADH-AES128-GCM-SHA256             DH 2048    AESGCM      128      TLS_DH_anon_WITH_AES_128_GCM_SHA256
 x6c     ADH-AES128-SHA256                 DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA256
 x34     ADH-AES128-SHA                    DH 2048    AES         128      TLS_DH_anon_WITH_AES_128_CBC_SHA
 xbf     ADH-CAMELLIA128-SHA256            DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA256
 x9b     ADH-SEED-SHA                      DH 2048    SEED        128      TLS_DH_anon_WITH_SEED_CBC_SHA
 x46     ADH-CAMELLIA128-SHA               DH 2048    Camellia    128      TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA
 x9c     AES128-GCM-SHA256                 RSA        AESGCM      128      TLS_RSA_WITH_AES_128_GCM_SHA256
 x3c     AES128-SHA256                     RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA256
 x2f     AES128-SHA                        RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA
 xba     CAMELLIA128-SHA256                RSA        Camellia    128      TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256
 x96     SEED-SHA                          RSA        SEED        128      TLS_RSA_WITH_SEED_CBC_SHA
 x41     CAMELLIA128-SHA                   RSA        Camellia    128      TLS_RSA_WITH_CAMELLIA_128_CBC_SHA
 xc050   ARIA128-GCM-SHA256                RSA        ARIAGCM     128      TLS_RSA_WITH_ARIA_128_GCM_SHA256
 xc052   DHE-RSA-ARIA128-GCM-SHA256        DH 2048    ARIAGCM     128      TLS_DHE_RSA_WITH_ARIA_128_GCM_SHA256
 xc060   ECDHE-ARIA128-GCM-SHA256          ECDH 253   ARIAGCM     128      TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256
TLS 1.3
 x1302   TLS_AES_256_GCM_SHA384            ECDH 253   AESGCM      256      TLS_AES_256_GCM_SHA384
 x1303   TLS_CHACHA20_POLY1305_SHA256      ECDH 253   ChaCha20    256      TLS_CHACHA20_POLY1305_SHA256
 x1301   TLS_AES_128_GCM_SHA256            ECDH 253   AESGCM      128      TLS_AES_128_GCM_SHA256

With switching our SSL certificate to RSA, we gained around 51 new cipher options, amongst them being ones that also mx01.arz.at claimed to support. FTR, the result from above is what you get with the default settings for postfix v3.5.18, being:

smtpd_tls_ciphers = medium
smtpd_tls_mandatory_ciphers = medium
smtpd_tls_mandatory_exclude_ciphers =
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3

But the delay between triggering the password reset mail and getting a mail server connect was getting bigger and bigger. Therefore while waiting for the next mail to arrive, I decided to capture the network traffic, to be able to look further into this if it should continue to be failing:

% sudo tshark -n -i eth0 -s 65535 -w arz.pcap -f "host 193.110.182.61 or host 193.110.182.62"

A few hours later the mail server connected again, and the mail went through!

postfix/smtpd[4162835]: connect from mx01.arz.at[193.110.182.61]
postfix/smtpd[4162835]: Anonymous TLS connection established from mx01.arz.at[193.110.182.61]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
postfix/smtpd[4162835]: E50D6401E6: client=mx01.arz.at[193.110.182.61]
postfix/smtpd[4162835]: disconnect from mx01.arz.at[193.110.182.61] ehlo=2 starttls=1 mail=1 rcpt=1 data=1 quit=1 commands=7

Now also having the captured network traffic, we can check the details there:

[...]
% tshark -o smtp.decryption:true -r arz.pcap
    1 0.000000000 193.110.182.61   203.0.113.42 TCP 74 24699   25 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=2261106119 TSecr=0 WS=128
    2 0.000042827 203.0.113.42   193.110.182.61 TCP 74 25   24699 [SYN, ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=3233422181 TSecr=2261106119 WS=128
    3 0.020719269 193.110.182.61   203.0.113.42 TCP 66 24699   25 [ACK] Seq=1 Ack=1 Win=29312 Len=0 TSval=2261106139 TSecr=3233422181
    4 0.022883259 203.0.113.42   193.110.182.61 SMTP 96 S: 220 mail.example.com ESMTP
    5 0.043682626 193.110.182.61   203.0.113.42 TCP 66 24699   25 [ACK] Seq=1 Ack=31 Win=29312 Len=0 TSval=2261106162 TSecr=3233422203
    6 0.043799047 193.110.182.61   203.0.113.42 SMTP 84 C: EHLO mx01.arz.at
    7 0.043811363 203.0.113.42   193.110.182.61 TCP 66 25   24699 [ACK] Seq=31 Ack=19 Win=65280 Len=0 TSval=3233422224 TSecr=2261106162
    8 0.043898412 203.0.113.42   193.110.182.61 SMTP 253 S: 250-mail.example.com   PIPELINING   SIZE 20240000   VRFY   ETRN   AUTH PLAIN   AUTH=PLAIN   ENHANCEDSTATUSCODES   8BITMIME   DSN   SMTPUTF8   CHUNKING
    9 0.064625499 193.110.182.61   203.0.113.42 SMTP 72 C: QUIT
   10 0.064750257 203.0.113.42   193.110.182.61 SMTP 81 S: 221 2.0.0 Bye
   11 0.064760200 203.0.113.42   193.110.182.61 TCP 66 25   24699 [FIN, ACK] Seq=233 Ack=25 Win=65280 Len=0 TSval=3233422245 TSecr=2261106183
   12 0.085573715 193.110.182.61   203.0.113.42 TCP 66 24699   25 [FIN, ACK] Seq=25 Ack=234 Win=30336 Len=0 TSval=2261106204 TSecr=3233422245
   13 0.085610229 203.0.113.42   193.110.182.61 TCP 66 25   24699 [ACK] Seq=234 Ack=26 Win=65280 Len=0 TSval=3233422266 TSecr=2261106204
   14 1799.888108373 193.110.182.61   203.0.113.42 TCP 74 10330   25 [SYN] Seq=0 Win=29200 Len=0 MSS=1460 SACK_PERM=1 TSval=2262906007 TSecr=0 WS=128
   15 1799.888161311 203.0.113.42   193.110.182.61 TCP 74 25   10330 [SYN, ACK] Seq=0 Ack=1 Win=65160 Len=0 MSS=1460 SACK_PERM=1 TSval=3235222069 TSecr=2262906007 WS=128
   16 1799.909030335 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=1 Ack=1 Win=29312 Len=0 TSval=2262906028 TSecr=3235222069
   17 1799.956621011 203.0.113.42   193.110.182.61 SMTP 96 S: 220 mail.example.com ESMTP
   18 1799.977229656 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=1 Ack=31 Win=29312 Len=0 TSval=2262906096 TSecr=3235222137
   19 1799.977229698 193.110.182.61   203.0.113.42 SMTP 84 C: EHLO mx01.arz.at
   20 1799.977266759 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=31 Ack=19 Win=65280 Len=0 TSval=3235222158 TSecr=2262906096
   21 1799.977351663 203.0.113.42   193.110.182.61 SMTP 267 S: 250-mail.example.com   PIPELINING   SIZE 20240000   VRFY   ETRN   STARTTLS   AUTH PLAIN   AUTH=PLAIN   ENHANCEDSTATUSCODES   8BITMIME   DSN   SMTPUTF8   CHUNKING
   22 1800.011494861 193.110.182.61   203.0.113.42 SMTP 76 C: STARTTLS
   23 1800.011589267 203.0.113.42   193.110.182.61 SMTP 96 S: 220 2.0.0 Ready to start TLS
   24 1800.032812294 193.110.182.61   203.0.113.42 TLSv1 223 Client Hello
   25 1800.032987264 203.0.113.42   193.110.182.61 TLSv1.2 2962 Server Hello
   26 1800.032995513 203.0.113.42   193.110.182.61 TCP 1266 25   10330 [PSH, ACK] Seq=3158 Ack=186 Win=65152 Len=1200 TSval=3235222214 TSecr=2262906151 [TCP segment of a reassembled PDU]
   27 1800.053546755 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=186 Ack=3158 Win=36096 Len=0 TSval=2262906172 TSecr=3235222214
   28 1800.092852469 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=186 Ack=4358 Win=39040 Len=0 TSval=2262906212 TSecr=3235222214
   29 1800.092892905 203.0.113.42   193.110.182.61 TLSv1.2 900 Certificate, Server Key Exchange, Server Hello Done
   30 1800.113546769 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=186 Ack=5192 Win=41856 Len=0 TSval=2262906232 TSecr=3235222273
   31 1800.114763363 193.110.182.61   203.0.113.42 TLSv1.2 192 Client Key Exchange, Change Cipher Spec, Encrypted Handshake Message
   32 1800.115000416 203.0.113.42   193.110.182.61 TLSv1.2 117 Change Cipher Spec, Encrypted Handshake Message
   33 1800.136070200 193.110.182.61   203.0.113.42 TLSv1.2 113 Application Data
   34 1800.136155526 203.0.113.42   193.110.182.61 TLSv1.2 282 Application Data
   35 1800.158854473 193.110.182.61   203.0.113.42 TLSv1.2 162 Application Data
   36 1800.159254794 203.0.113.42   193.110.182.61 TLSv1.2 109 Application Data
   37 1800.180286407 193.110.182.61   203.0.113.42 TLSv1.2 144 Application Data
   38 1800.223005960 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=5502 Ack=533 Win=65152 Len=0 TSval=3235222404 TSecr=2262906299
   39 1802.230300244 203.0.113.42   193.110.182.61 TLSv1.2 146 Application Data
   40 1802.251994333 193.110.182.61   203.0.113.42 TCP 2962 [TCP segment of a reassembled PDU]
   41 1802.252034015 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=5582 Ack=3429 Win=63616 Len=0 TSval=3235224433 TSecr=2262908371
   42 1802.252279083 193.110.182.61   203.0.113.42 TLSv1.2 1295 Application Data
   43 1802.252288316 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=5582 Ack=4658 Win=64128 Len=0 TSval=3235224433 TSecr=2262908371
   44 1802.272816060 193.110.182.61   203.0.113.42 TLSv1.2 833 Application Data, Application Data
   45 1802.272827542 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=5582 Ack=5425 Win=64128 Len=0 TSval=3235224453 TSecr=2262908392
   46 1802.338807683 203.0.113.42   193.110.182.61 TLSv1.2 131 Application Data
   47 1802.398968611 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=5425 Ack=5647 Win=44800 Len=0 TSval=2262908518 TSecr=3235224519
   48 1863.257457500 193.110.182.61   203.0.113.42 TLSv1.2 101 Application Data
   49 1863.257495688 203.0.113.42   193.110.182.61 TCP 66 25   10330 [ACK] Seq=5647 Ack=5460 Win=64128 Len=0 TSval=3235285438 TSecr=2262969376
   50 1863.257654942 203.0.113.42   193.110.182.61 TLSv1.2 110 Application Data
   51 1863.257721010 203.0.113.42   193.110.182.61 TLSv1.2 97 Encrypted Alert
   52 1863.278242216 193.110.182.61   203.0.113.42 TCP 66 10330   25 [ACK] Seq=5460 Ack=5691 Win=44800 Len=0 TSval=2262969397 TSecr=3235285438
   53 1863.278464176 193.110.182.61   203.0.113.42 TCP 66 10330   25 [RST, ACK] Seq=5460 Ack=5723 Win=44800 Len=0 TSval=2262969397 TSecr=3235285438

% tshark -O tls -r arz.pcap
[...]
Transport Layer Security
    TLSv1 Record Layer: Handshake Protocol: Client Hello
        Content Type: Handshake (22)
        Version: TLS 1.0 (0x0301)
        Length: 152
        Handshake Protocol: Client Hello
            Handshake Type: Client Hello (1)
            Length: 148
            Version: TLS 1.2 (0x0303)
            Random: 4575d1e7c93c09a564edc00b8b56ea6f5d826f8cfe78eb980c451a70a9c5123f
                GMT Unix Time: Dec  5, 2006 21:09:11.000000000 CET
                Random Bytes: c93c09a564edc00b8b56ea6f5d826f8cfe78eb980c451a70a9c5123f
            Session ID Length: 0
            Cipher Suites Length: 26
            Cipher Suites (13 suites)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (0xc030)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (0xc02f)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (0xc028)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (0xc027)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014)
                Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013)
                Cipher Suite: TLS_RSA_WITH_AES_256_GCM_SHA384 (0x009d)
                Cipher Suite: TLS_RSA_WITH_AES_128_GCM_SHA256 (0x009c)
                Cipher Suite: TLS_RSA_WITH_AES_256_CBC_SHA256 (0x003d)
                Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA256 (0x003c)
                Cipher Suite: TLS_RSA_WITH_AES_256_CBC_SHA (0x0035)
                Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA (0x002f)
                Cipher Suite: TLS_EMPTY_RENEGOTIATION_INFO_SCSV (0x00ff)
[...]
Transport Layer Security
    TLSv1.2 Record Layer: Handshake Protocol: Server Hello
        Content Type: Handshake (22)
        Version: TLS 1.2 (0x0303)
        Length: 89
        Handshake Protocol: Server Hello
            Handshake Type: Server Hello (2)
            Length: 85
            Version: TLS 1.2 (0x0303)
            Random: cf2ed24e3300e95e5f56023bf8b4e5904b862bb2ed8a5796444f574e47524401
                GMT Unix Time: Feb 23, 2080 23:16:46.000000000 CET
                Random Bytes: 3300e95e5f56023bf8b4e5904b862bb2ed8a5796444f574e47524401
            Session ID Length: 32
            Session ID: 63d041b126ecebf857d685abd9d4593c46a3672e1ad76228f3eacf2164f86fb9
            Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (0xc030)
[...]

In this network dump we see what cipher suites are offered, and the TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 here is the Cipher Suite Name in IANA/RFC speak. Whis corresponds to the ECDHE-RSA-AES256-GCM-SHA384 in openssl speak (see Mozilla s Mozilla s cipher suite correspondence table), which we also saw in the postfix log. Mission accomplished! :) Now, if we re interested in avoiding certain ciphers and increase security level, we can e.g. get rid of the SEED, CAMELLIA and all anonymous ciphers, and could accept only TLS v1.2 + v1.3, by further adjusting postfix s main.cf:

smtpd_tls_ciphers = high
smtpd_tls_exclude_ciphers = aNULL CAMELLIA
smtpd_tls_mandatory_ciphers = high
smtpd_tls_mandatory_protocols = TLSv1.2 TLSv1.3
smtpd_tls_protocols = TLSv1.2 TLSv1.3

Which would then gives us:

% testssl --cipher-per-proto -t=smtp mail.example.com:25
[...]
Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
-----------------------------------------------------------------------------------------------------------------------------
SSLv2
SSLv3
TLS 1
TLS 1.1
TLS 1.2
 xc030   ECDHE-RSA-AES256-GCM-SHA384       ECDH 253   AESGCM      256      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
 xc028   ECDHE-RSA-AES256-SHA384           ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
 xc014   ECDHE-RSA-AES256-SHA              ECDH 253   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
 x9f     DHE-RSA-AES256-GCM-SHA384         DH 2048    AESGCM      256      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
 xcca8   ECDHE-RSA-CHACHA20-POLY1305       ECDH 253   ChaCha20    256      TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 xccaa   DHE-RSA-CHACHA20-POLY1305         DH 2048    ChaCha20    256      TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 xc0a3   DHE-RSA-AES256-CCM8               DH 2048    AESCCM8     256      TLS_DHE_RSA_WITH_AES_256_CCM_8
 xc09f   DHE-RSA-AES256-CCM                DH 2048    AESCCM      256      TLS_DHE_RSA_WITH_AES_256_CCM
 x6b     DHE-RSA-AES256-SHA256             DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
 x39     DHE-RSA-AES256-SHA                DH 2048    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA
 x9d     AES256-GCM-SHA384                 RSA        AESGCM      256      TLS_RSA_WITH_AES_256_GCM_SHA384
 xc0a1   AES256-CCM8                       RSA        AESCCM8     256      TLS_RSA_WITH_AES_256_CCM_8
 xc09d   AES256-CCM                        RSA        AESCCM      256      TLS_RSA_WITH_AES_256_CCM
 x3d     AES256-SHA256                     RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA256
 x35     AES256-SHA                        RSA        AES         256      TLS_RSA_WITH_AES_256_CBC_SHA
 xc051   ARIA256-GCM-SHA384                RSA        ARIAGCM     256      TLS_RSA_WITH_ARIA_256_GCM_SHA384
 xc053   DHE-RSA-ARIA256-GCM-SHA384        DH 2048    ARIAGCM     256      TLS_DHE_RSA_WITH_ARIA_256_GCM_SHA384
 xc061   ECDHE-ARIA256-GCM-SHA384          ECDH 253   ARIAGCM     256      TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384
 xc02f   ECDHE-RSA-AES128-GCM-SHA256       ECDH 253   AESGCM      128      TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
 xc027   ECDHE-RSA-AES128-SHA256           ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
 xc013   ECDHE-RSA-AES128-SHA              ECDH 253   AES         128      TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
 x9e     DHE-RSA-AES128-GCM-SHA256         DH 2048    AESGCM      128      TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
 xc0a2   DHE-RSA-AES128-CCM8               DH 2048    AESCCM8     128      TLS_DHE_RSA_WITH_AES_128_CCM_8
 xc09e   DHE-RSA-AES128-CCM                DH 2048    AESCCM      128      TLS_DHE_RSA_WITH_AES_128_CCM
 xc0a0   AES128-CCM8                       RSA        AESCCM8     128      TLS_RSA_WITH_AES_128_CCM_8
 xc09c   AES128-CCM                        RSA        AESCCM      128      TLS_RSA_WITH_AES_128_CCM
 x67     DHE-RSA-AES128-SHA256             DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
 x33     DHE-RSA-AES128-SHA                DH 2048    AES         128      TLS_DHE_RSA_WITH_AES_128_CBC_SHA
 x9c     AES128-GCM-SHA256                 RSA        AESGCM      128      TLS_RSA_WITH_AES_128_GCM_SHA256
 x3c     AES128-SHA256                     RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA256
 x2f     AES128-SHA                        RSA        AES         128      TLS_RSA_WITH_AES_128_CBC_SHA
 xc050   ARIA128-GCM-SHA256                RSA        ARIAGCM     128      TLS_RSA_WITH_ARIA_128_GCM_SHA256
 xc052   DHE-RSA-ARIA128-GCM-SHA256        DH 2048    ARIAGCM     128      TLS_DHE_RSA_WITH_ARIA_128_GCM_SHA256
 xc060   ECDHE-ARIA128-GCM-SHA256          ECDH 253   ARIAGCM     128      TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256
TLS 1.3
 x1302   TLS_AES_256_GCM_SHA384            ECDH 253   AESGCM      256      TLS_AES_256_GCM_SHA384
 x1303   TLS_CHACHA20_POLY1305_SHA256      ECDH 253   ChaCha20    256      TLS_CHACHA20_POLY1305_SHA256
 x1301   TLS_AES_128_GCM_SHA256            ECDH 253   AESGCM      128      TLS_AES_128_GCM_SHA256

Don t forget to also adjust the smpt_tls_* accordingly (for your sending side). For further information see the Postfix TLS Support documentation. Also check out options like tls_ssl_options (setting it to e.g. NO_COMPRESSION) and tls_preempt_cipherlist (setting it to yes would prefer the servers order of ciphers over clients). Conclusions:

no matter what you change in your mail server settings, be aware that the type of your SSL certificate also matters for what ciphers are offered and used
there are mail servers out there that don t support SSL certificates with ECDSA, using RSA for those ensure better compatibility (nowadays postfix supports parallel usage of ECDSA and RSA keys BTW, check out the smtpd_tls_eccert_file + smtpd_tls_eckey_file options)
testssl is a very useful tool, especially with its cipher-per-proto -t=smtp option to check SMTP servers
if you re uncertain what s going on, consider capturing network data (tshark/tcpdump/ are your friends)
review your postfix configuration and logs every now and then :)

TL;DR: Color is a visual perception. Human eyes can detect a broader range of colors than any devices in the graphics chain. Since each device can generate, capture or reproduce a specific subset of colors and tones, color management controls color conversion and calibration across devices to ensure a more accurate and consistent color representation. We can expose a GPU-accelerated display color management pipeline to support this process and enhance results, and this is what we are doing on Linux to improve color management on `Gamescope/SteamDeck`. Even with the challenges of being external developers, we have been working on mapping `AMD GPU color capabilities` to `the Linux kernel color management interface`, which is a combination of DRM and AMD driver-specific color properties. This more extensive color management pipeline includes `pre-defined Transfer Functions`, `1-Dimensional LookUp Tables (1D LUTs)`, and `3D LUTs` before and after the plane composition/blending.
The study of color is well-established and has been explored for many years. Color science and research findings have also guided technology innovations. As a result, color in Computer Graphics is a very complex topic that I m putting a lot of effort into becoming familiar with. I always find myself rereading all the materials I have collected about color space and operations since I started this journey (about one year ago). I also understand how hard it is to find consensus on some color subjects, as exemplified by all explanations around the 2015 online viral phenomenon of The Black and Blue Dress. Have you heard about it? What is the color of the dress for you? So, taking into account my skills with colors and building consensus, this blog post only focuses on GPU hardware capabilities to support color management :-D If you want to learn more about color concepts and color on Linux, you can find useful links at the end of this blog post.

Linux Kernel, show me the colors ;D DRM color management interface only exposes a small set of post-blending color properties. Proposals to enhance the DRM color API from different vendors have landed the subsystem mailing list over the last few years. On one hand, we got some suggestions to extend DRM post-blending/CRTC color API: DRM CRTC 3D LUT for R-Car (2020 version); DRM CRTC 3D LUT for Intel (draft - 2020); DRM CRTC 3D LUT for AMD by Igalia (v2 - 2023); DRM CRTC 3D LUT for R-Car (v2 - 2023). On the other hand, some proposals to extend DRM pre-blending/plane API: DRM plane colors for Intel (v2 - 2021); DRM plane API for AMD (v3 - 2021); DRM plane 3D LUT for AMD - 2021. Finally, Simon Ser sent the latest proposal in May 2023: Plane color pipeline KMS uAPI, from discussions in the 2023 Display/HDR Hackfest, and it is still under evaluation by the Linux Graphics community. All previous proposals seek a generic solution for expanding the API, but many seem to have stalled due to the uncertainty of matching well the hardware capabilities of all vendors. Meanwhile, the use of AMD color capabilities on Linux remained limited by the DRM interface, as the `DCN 3.0 family color caps and mapping` diagram below shows the Linux/DRM color interface without driver-specific color properties [*]: Bearing in mind that we need to know the variety of color pipelines in the subsystem to be clear about a generic solution, we decided to approach the issue from a different perspective and worked on enabling a set of `Driver-Specific Color Properties for AMD Display Drivers`. As a result, I recently sent another round of the AMD driver-specific color mgmt API. For those who have been following the AMD driver-specific proposal since the beginning (see [RFC][V1]), the main new features of the latest version [v2] are the addition of `pre-blending Color Transformation Matrix (plane CTM)` and the differentiation of `Pre-defined Transfer Functions (TF)` supported by color blocks. For those who just got here, I will recap this work in two blog posts. This one describes the current status of the AMD display driver in the Linux kernel/DRM subsystem and what changes with the driver-specific properties. In the next post, we go deeper to describe the features of each color block and provide a better picture of what is available in terms of color management for Linux.

The Linux kernel color management API and AMD hardware color capabilities Before discussing colors in the Linux kernel with AMD hardware, consider accessing the Linux kernel documentation (version 6.5.0-rc5). In the AMD Display documentation, you will find my previous work documenting AMD hardware color capabilities and the Color Management Properties. It describes how `AMD Display Manager (DM)` intermediates requests between the `AMD Display Core component (DC)` and the `Linux/DRM kernel` interface for color management features. It also describes the relevant function to call the AMD color module in building curves for content space transformations. A subsection also describes hardware color capabilities and how they evolve between versions. This subsection, DC Color Capabilities between DCN generations, is a good starting point to understand what we have been doing on the kernel side to provide a broader color management API with AMD driver-specific properties.

Why do we need more kernel color properties on Linux? Blending is the process of combining multiple planes (framebuffers abstraction) according to their mode settings. Before blending, we can manage the colors of various planes separately; after blending, we have combined those planes in only one output per CRTC. Color conversions after blending would be enough in a single-plane scenario or when dealing with planes in the same color space on the kernel side. Still, it cannot help to handle the blending of multiple planes with different color spaces and luminance levels. With plane color management properties, userspace can get a more accurate representation of colors to deal with the diversity of color profiles of devices in the graphics chain, bring a `wide color gamut (WCG)`, convert `High-Dynamic-Range (HDR)` content to `Standard-Dynamic-Range (SDR)` content (and vice-versa). With a GPU-accelerated display color management pipeline, we can use hardware blocks for color conversions and color mapping and support advanced color management. The current DRM color management API enables us to perform some color conversions after blending, but there is no interface to calibrate input space by planes. Note that here I m not considering some workarounds in the AMD display manager mapping of DRM CRTC de-gamma and DRM CRTC CTM property to pre-blending DC de-gamma and gamut remap block, respectively. So, in more detail, it only exposes three post-blending features:

DRM CRTC de-gamma: used to convert the framebuffer s colors to linear gamma;

DRM CRTC CTM: used for color space conversion;

DRM CRTC gamma: used to convert colors to the gamma space of the connected screen.

AMD driver-specific color management interface We can compare the Linux color management API with and without the driver-specific color properties. From now, we denote driver-specific properties with the AMD prefix and generic properties with the DRM prefix. For visual comparison, I bring the `DCN 3.0 family color caps and mapping` diagram closer and present it here again: Mixing AMD driver-specific color properties with DRM generic color properties, we have a broader Linux color management system with the following features exposed by properties in the plane and CRTC interface, as summarized by this updated diagram: The blocks highlighted by `red lines` are the `new properties` in the driver-specific interface developed by me (Igalia) and Joshua (Valve). The `red dashed lines` are new `links between API and AMD driver components` implemented by us to connect the Linux/DRM interface to AMD hardware blocks, mapping components accordingly. In short, we have the following color management properties exposed by the DRM/AMD display driver:

Pre-blending - AMD Display Pipe and Plane (DPP):

AMD plane de-gamma: 1D LUT and pre-defined transfer functions; used to linearize the input space of a plane;

AMD plane CTM: 3x4 matrix; used to convert plane color space;

AMD plane shaper: 1D LUT and pre-defined transfer functions; used to delinearize and/or normalize colors before applying 3D LUT;

AMD plane 3D LUT: 17x17x17 size with 12 bit-depth; three dimensional lookup table used for advanced color mapping;

AMD plane blend/out gamma: 1D LUT and pre-defined transfer functions; used to linearize back the color space after 3D LUT for blending.

Post-blending - AMD Multiple Pipe/Plane Combined (MPC):

DRM CRTC de-gamma: 1D LUT (can t be set together with plane de-gamma);

DRM CRTC CTM: 3x3 matrix (remapped to post-blending matrix);

DRM CRTC gamma: 1D LUT + AMD CRTC gamma TF; added to take advantage of driver pre-defined transfer functions;

Note: You can find more about AMD display blocks in the Display Core Next (DCN) - Linux kernel documentation, provided by Rodrigo Siqueira (Linux/AMD display developer) in a 2021-documentation series. In the next post, I ll revisit this topic, explaining display and color blocks in detail.

How did we get a large set of color features from AMD display hardware? So, looking at AMD hardware color capabilities in the first diagram, we can see no post-blending (MPC) de-gamma block in any hardware families. We can also see that the AMD display driver maps CRTC/post-blending CTM to pre-blending (DPP) gamut_remap, but there is post-blending (MPC) gamut_remap (DRM CTM) from newer hardware versions that include SteamDeck hardware. You can find more details about hardware versions in the Linux kernel documentation/AMDGPU Product Information. I needed to rework these two mappings mentioned above to provide pre-blending/plane de-gamma and CTM for SteamDeck. I changed the DC mapping to detach `stream gamut remap` matrixes from the `DPP gamut remap` block. That means mapping AMD plane CTM directly to DPP/pre-blending gamut remap block and DRM CRTC CTM to MPC/post-blending gamut remap block. In this sense, I also limited plane CTM properties to those hardware versions with MPC/post-blending gamut_remap capabilities since older versions cannot support this feature without clashes with DRM CRTC CTM. Unfortunately, I couldn t prevent conflict between AMD plane de-gamma and DRM plane de-gamma since post-blending de-gamma isn t available in any AMD hardware versions until now. The fact is that a post-blending de-gamma makes little sense in the AMD color pipeline, where plane blending works better in a linear space, and there are enough color blocks to linearize content before blending. To deal with this conflict, the driver now rejects atomic commits if users try to set both AMD plane de-gamma and DRM CRTC de-gamma simultaneously. Finally, we had no other clashes when enabling other AMD driver-specific color properties for our use case, Gamescope/SteamDeck. Our main work for the remaining properties was understanding the data flow of each property, the hardware capabilities and limitations, and how to shape the data for programming the registers - AMD color block capabilities (and limitations) are the topics of the next blog post. Besides that, we fixed some driver bugs along the way since it was the first Linux use case for most of the new color properties, and some behaviors are only exposed when exercising the engine. Take a look at the Gamescope/Steam Deck Color Pipeline[**], and see how Gamescope uses the new API to manage color space conversions and calibration (please click on the image for a better view): In the next blog post, I ll describe the implementation and technical details of each pre- and post-blending color block/property on the AMD display driver. * Thank Harry Wentland for helping with diagrams, color concepts and AMD capabilities. Thank Joshua Ashton for providing and explaining Gamescope/Steam Deck color pipeline. * Thanks to the Linux Graphics community - explicitly Harry, Joshua, Pekka, Simon, Sebastian, Siqueira, Alex H. and Ville - to all the learning during this Linux DRM/AMD color journey. Also, Carlos and Tomas for organizing the 2023 Display/HDR Hackfest where we have a great and immersive opportunity to discuss Color & HDR on Linux.

Useful Links

Cinematic Color - 2012 SIGGRAPH course notes by Jeremy Selan: an introduction to color science, concepts and pipelines.

Color management and HDR documentation for FOSS graphics by Pekka Paalanen: documentation and useful links on applying color concepts to the Linux graphics stack.

HDR in Linux by Jeremy Cline: a blog post exploring color concepts for HDR support on Linux.

Methods for conversion of high dynamic range content to standard dynamic range content and vice-versa by ITU-R: guideline for conversions between HDR and SDR contents.

Using Lookup Tables to Accelerate Color Transformations by Jeremy Selan: Nvidia blog post about Lookup Tables on color management.

The Importance of Being Linear by Larry Gritz and Eugene d Eon: Nvidia blog post about gamma and color conversions.

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

Marcel Fourn et al. presented at the IEEE Symposium on Security and Privacy in San Francisco, CA on The Importance and Challenges of Reproducible Builds for Software Supply Chain Security. As summarised in last month s report, the abstract of their paper begins:

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. (PDF)

Chris Lamb published an interview with Simon Butler, associate senior lecturer in the School of Informatics at the University of Sk vde, on the business adoption of Reproducible Builds. (This is actually the seventh instalment in a series featuring the projects, companies and individuals who support our project. We started this series by featuring the Civil Infrastructure Platform project, and followed this up with a post about the Ford Foundation as well as recent ones about ARDC, the Google Open Source Security Team (GOSST), Bootstrappable Builds, the F-Droid project and David A. Wheeler.)

Vagrant Cascadian presented Breaking the Chains of Trusting Trust at FOSSY 2023.

Rahul Bajaj has been working with Roland Clobus on merging an overview of environment variations to our website:

I have identified 16 root causes for unreproducible builds in my empirical study, which I have linked to the corresponding documentation. The initial MR right now contains information about 10 root causes. For each root cause, I have provided a definition, a notable instance, and a workaround. However, I have only found workarounds for 5 out of the 10 root causes listed in this merge request. In the upcoming commits, I plan to add an additional 6 root causes. I kindly request you review the text for any necessary refinements, modifications, or corrections. Additionally, I would appreciate the help with documentation for the solutions/workarounds for the remaining root causes: Archive Metadata, Build ID, File System Ordering, File Permissions, and Snippet Encoding. Your input on the identified root causes for unreproducible builds would be greatly appreciated. [ ]

Just a reminder that our upcoming Reproducible Builds Summit is set to take place from October 31st November 2nd 2023 in 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. If you re interested in joining us this year, please make sure to read the event page which has more details about the event and location.

There was more progress towards making the Go programming language ecosystem reproducible this month, including:

Adding a new subpage on the GoLang website to show reproduction of the published Go binaries, along with release candidates along with a new binary to produce the given results. This has resulted in page of unreproducible packages as well as a reproducible releases page. This was achieved via Go bug #513700.
In addition a tool to reproduce posted Go binaries was added: This command rebuilds or verifies all the artifacts [ ] for the latest supported releases.

In addition, kpcyrd posted to our mailing list to report that:

while packaging govulncheck for Arch Linux I noticed a checksum mismatch for a tar file I downloaded from go.googlesource.com. I used diffoscope to compare the .tar file I downloaded with the .tar file the build server downloaded, and noticed the timestamps are different.

In Debian, 20 reviews of Debian packages were added, 25 were updated and 25 were removed this month adding to our knowledge about identified issues. A number of issue types were updated, including marking ffile_prefix_map_passed_to_clang being fixed since Debian bullseye [ ] and adding a Debian bug tracker reference for the nondeterminism_added_by_pyqt5_pyrcc5 issue [ ]. In addition, Roland Clobus posted another detailed update of the status of reproducible Debian ISO images on our mailing list. In particular, Roland helpfully summarised that live images are looking good, and the number of (passing) automated tests is growing .

Bernhard M. Wiedemann published another monthly report about reproducibility within openSUSE.

F-Droid added 20 new reproducible apps in July, making 165 apps in total that are published with Reproducible Builds and using the upstream developer s signature. [ ]
The Sphinx documentation tool recently accepted a change to improve deterministic reproducibility of documentation. It s internal util.inspect.object_description attempts to sort collections, but this can fail. The change handles the failure case by using string-based object descriptions as a fallback deterministic sort ordering, as well as adding recursive object-description calls for list and tuple datatypes. As a result, documentation generated by Sphinx will be more likely to be automatically reproducible. Lastly in news, kpcyrd posted to our mailing list announcing a new repro-env tool:

My initial interest in reproducible builds was how do I distribute pre-compiled binaries on GitHub without people raising security concerns about them . I ve cycled back to this original problem about 5 years later and built a tool that is meant to address this. [ ]

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:

Bernhard M. Wiedemann:

`django-graphql-jwt` (fails to build in 2038)

`doxygen` (filesystem ordering issue)

`git-interactive-rebase-tool` (date-related issue)

`obs-build`

`procmeter` (parallelism race condition)

`promu`

`python-cx_Freeze` (version update for year 2038 fix)

`python-zope.deprecation`

`python310` (ASLR-related issue)

`python-control` (fails to build-j4)

`python-DateTime` (fails to build in 2038)

`python-pyface` (date/time-related issue)

`python-quantities` (date/time-related issue)

`python-scipy` (date/time-related issue)

`rpmlint`

`starship` (filesystem ordering issue)

`Telethon`

`xindy` (fails to build in 2036)

`yt` (filesystem ordering issue)

Drop Sphinx doctrees in `python-bpython`, `python-flup`, `python-mysqlclient`, `python-waitress`, `python-WebOb`, `python-WebTest`, `python-zope.event`, `python-zope.hookable` & `python-zope.i18nmessageid`

Chris Lamb (lamby):

#1040232 filed against `dotenv-cli`.

#1040904 filed against `unity-java`.

#1041840 filed against `ruby-babosa` (forwarded upstream).

#1041842 filed against `guidata` (forwarded upstream).

Johannes Schauer Marin Rodrigues (josch):

#1040450 filed against `binutils`.

John Neffenger:

openjdk/jfx#446 (openjfx), Enable reproducible builds with `SOURCE_DATE_EPOCH`, a three-and-a-half year effort started by Bernhard M. Wiedemann in January 2020, taken over by John Neffenger in March 2021, integrated upstream in June 2023, and available starting with JavaFX 21 on September 19, 2023.

In diffoscope development this month, versions `244`, `245` and `246` were uploaded to Debian unstable by Chris Lamb, who also made the following changes:

Don t include the file size in image metadata. It is, at best, distracting, and it is already in the directory metadata. [ ]

Add compatibility with `libarchive-5`. [ ]

Mark that the `test_dex::test_javap_14_differences` test requires the `procyon` tool. [ ]

Initial work on DOS/MBR extraction. [ ]

Move to using `assert_diff` in the `.ico` and `.jpeg` tests. [ ]

Temporarily mark some Android-related as `XFAIL` due to Debian bugs #1040941 & #1040916. [ ]

Fix the test skipped reason generation in the case of a version outside of the required range. [ ]

Update copyright years. [ ][ ]

Fix try.diffoscope.org. [ ]

In addition, Gianfranco Costamagna added support for LLVM version 16. [ ]

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 July, a number of changes were made by Holger Levsen:

General changes:

Upgrade Jenkins host to Debian bookworm now that Debian 12.1 is out. [ ][ ][ ][ ]

djm: improve UX when rebooting a node fails. [ ]

djm: reduce wait time between rebooting nodes. [ ]

Debian-related changes:

Various refactoring of the Debian scheduler. [ ][ ][ ]

Make Debian live builds more robust with respect to salsa.debian.org returning HTTP 502 errors. [ ][ ]

Use the legacy SCP protocol instead of the SFTP protocol when transfering Debian live builds. [ ][ ]

Speed up a number of database queries thanks, Myon! [ ][ ][ ][ ][ ]

Split `create_meta_pkg_sets` job into two (for Debian unstable and Debian testing) to half the job runtime to approximately 90 minutes. [ ][ ]

Split scheduler job into four separate jobs, one for each tested architecture. [ ][ ]

Treat more PostgreSQL errors as serious (for some jobs). [ ]

Re-enable automatic database documentation now that `postgresql_autodoc` is back in Debian bookworm. [ ]

Remove various hardcoding of Debian release names. [ ]

Drop some i386 special casing. [ ]

Other distributions:

Speed up Alpine SQL queries. [ ]

Adjust CSS layout for Arch Linux pages to match 3 and not 4 repos being tested. [ ]

Drop the community Arch Linux repo as it has now been merged into the extra repo. [ ]

Speed up a number of Arch-related database queries. [ ]

Try harder to properly cleanup after building OpenWrt packages. [ ]

Drop all `kfreebsd`-related tests now that it s officially dead. [ ]

System health:

Always ignore some well-known harmless orphan processes. [ ][ ][ ]

Detect another case of job failure due to Jenkins shutdown. [ ]

Show all non co-installable package sets on the status page. [ ]

Warn that some specific reboot nodes are currently false-positives. [ ]

Node health checks:

Run system and node health checks for Jenkins less frequently. [ ]

Try to restart any failed `dpkg-db-backup` [ ] and `munin-node services` [ ].

In addition, Vagrant Cascadian updated the paths in our automated to tests to use the same paths used by the official Debian build servers. [ ]

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:

IRC: `#reproducible-builds` on `irc.oftc.net`.

Mailing list: `rb-general@lists.reproducible-builds.org`

Mastodon: @reproducible_builds@fosstodon.org

Twitter: @ReproBuilds

The Reproducible Builds project relies on several projects, supporters and sponsors for financial support, but they are also valued as ambassadors who spread the word about our project and the work that we do. This is the seventh instalment in a series featuring the projects, companies and individuals who support the Reproducible Builds project. We started this series by featuring the Civil Infrastructure Platform project, and followed this up with a post about the Ford Foundation as well as recent ones about ARDC, the Google Open Source Security Team (GOSST), Bootstrappable Builds, the F-Droid project and David A. Wheeler. Today, however, we will be talking with Simon Butler, an associate senior lecturer in the School of Informatics at the University of Sk vde, where he undertakes research in software engineering that focuses on IoT and open source software, and contributes to the teaching of computer science to undergraduates.

Chris: For those who have not heard of it before, can you tell us more about the School of Informatics at Sk vde University? Simon: Certainly, but I may be a little long-winded. Sk vde is a city in the area between the two large lakes in southern Sweden. The city is a busy place. Sk vde is home to the regional hospital, some of Volvo s manufacturing facilities, two regiments of the Swedish defence force, a lot of businesses in the Swedish computer games industry, other tech companies and more.

The University of Sk vde is relatively small. Sweden s large land area and low population density mean that regional centres such as Sk vde are important and local universities support businesses by training new staff and supporting innovation. The School of Informatics has two divisions. One focuses on teaching and researching computer games. The other division encompasses a wider range of teaching and research, including computer science, web development, computer security, network administration, data science and so on.

Chris: You recently had a open-access paper published in Software Quality Journal. Could you tell us a little bit more about it and perhaps briefly summarise its key findings? Simon: The paper is one output of a collaborative research project with six Swedish businesses that use open source software. There are two parts to the paper. The first consists of an analysis of what the group of businesses in the project know about Reproducible Builds (R-Bs), their experiences with R-Bs and their perception of the value of R-Bs to the businesses. The second part is an interview study with business practitioners and others with experience and expertise in R-Bs. We set out to try to understand the extent to which software-intensive businesses were aware of R-Bs, the technical and business reasons they were or were not using R-Bs and to document the business and technical use cases for R-Bs. The key findings were that businesses are aware of R-Bs, and some are using R-Bs as part of their day-to-day development process. Some of the uses for R-Bs we found were not previously documented. We also found that businesses understood the value R-Bs have as part of engineering and software quality processes. They are also aware of the costs of implementing R-Bs and that R-Bs are an intangible value proposition - in other words, businesses can add value through process improvement by using R-Bs. But, that, currently at least, R-Bs are not a selling point for software or products.
Chris: You performed a large number of interviews in order to prepare your paper. What was the most surprising response to you? Simon: Most surprising is a good question. Everybody I spoke to brought something new to my understanding of R-Bs, and many responses surprised me. The interviewees that surprised me most were I01 and I02 (interviews were anonymised and interviewees were assigned numeric identities). I02 described the sceptical perspective that there is a viable, pragmatic alternative to R-Bs - verifiable builds - which I was aware of before undertaking the research. The company had developed a sufficiently robust system for their needs and worked well. With a large archive of software used in production, they couldn t justify the cost of retrofitting a different solution that might only offer small advantages over the existing system. Doesn t really sound too surprising, but the interview was one of the first I did on this topic, and I was very focused on the value of, and need for, trust in a system that motivated the R-B. The solution used by the company requires trust, but they seem to have established sufficient trust for their needs by securing their build systems to the extent that they are more or less tamper-proof. The other big surprise for me was I01 s use of R-Bs to support the verification of system configuration in a system with multiple embedded components at boot time. It s such an obvious application of R-Bs, and exactly the kind of response I hoped to get from interviewees. However, it is another instance of a solution where trust is only one factor. In the first instance, the developer is using R-Bs to establish trust in the toolchain. There is also the second application that the developer can use a set of R-Bs to establish that deployed system consists of compatible components. While this might not sound too significant, there appear to be some important potential applications. One that came to mind immediately is a problem with firmware updates on nodes in IoT systems where the node needs to update quickly with limited downtime and without failure. The node also needs to be able to roll back any update proposed by a server if there are conflicts with the current configuration or if any tests on the node fail. Perhaps the chances of failure could be reduced, if a node can instead negotiate with a server to determine a safe path to migrate from its current configuration to a working configuration with the upgraded components the central system requires? Another potential application appears to be in the configuration management of AI systems, where decisions need to be explainable. A means of specifying validated configurations of training data, models and deployed systems might, perhaps, be leveraged to prevent invalid or broken configurations from being deployed in production.
Chris: One of your findings was that reproducible builds were perceived to be good engineering practice . To what extent do you believe cultural forces affect the adoption or rejection of a given technology or practice? Simon: To a large extent. People s decisions are informed by cultural norms, and business decisions are made by people acting collectively. Of course, decision-making, including assessments of risk and usefulness, is mediated by individual positions on the continuum from conformity to non-conformity, as well as individual and in-group norms. Whether a business will consider a given technology for adoption will depend on cultural forces. The decision to adopt may well be made on the grounds of cost and benefits.
Chris: Another conclusion implied by your research is that businesses are often dealing with software deployment lifespans (eg. 20+ years) that differ from widely from those of the typical hobbyist programmer. To what degree do you think this temporal mismatch is a problem for both groups? Simon: This is a fascinating question. Long-term software maintenance is a requirement in some industries because of the working lifespans of the products and legal requirements to maintain the products for a fixed period. For some other industries, it is less of a problem. Consequently, I would tend to divide developers into those who have been exposed to long-term maintenance problems and those who have not. Although, more professional than hobbyist developers will have been exposed to the problem. Nonetheless, there are areas, such as music software, where there are also long-term maintenance challenges for data formats and software.
Chris: Based on your research, what would you say are the biggest blockers for the adoption of reproducible builds within business ? And, based on this, would you have any advice or recommendations for the broader reproducible builds ecosystem? Simon: From the research, the main blocker appears to be cost. Not an absolute cost, but there is an overhead to introducing R-Bs. Businesses (and thus business managers) need to understand the business case for R-Bs.

Making decision-makers in businesses aware of R-Bs and that they are valuable will take time. Advocacy at multiple levels appears to be the way forward and this is being done. I would recommend being persistent while being patient and to keep talking about reproducible builds. The work done in Linux distributions raises awareness of R-Bs amongst developers. Guix, NixOS and Software Heritage are all providing practical solutions and getting attention - I ve been seeing progressively more mentions of all three during the last couple of years. Increased awareness amongst developers should lead to more interest within companies. There is also research money being assigned to supply chain security and R-B s. The CHAINS project at KTH in Stockholm is one example of a strategic research project. There may be others that I m not aware of. The policy-level advocacy is slowly getting results in some countries, and where CISA leads, others may follow.
Chris: Was there a particular reason you alighted on the question of the adoption of reproducible builds in business? Do you think there s any truth behind the shopworn stereotype of hacker types neglecting the resources that business might be able to offer? Simon: Much of the motivation for the research came from the contrast between the visibility of R-Bs in open source projects and the relative invisibility of R-Bs in industry. Where companies are known to be using R-Bs (e.g. Google, etc.) there is no fuss, no hype. They were not selling R-Bs as a solution; instead the documentation is very matter-of-fact that R-Bs are part of a customer-facing process in their cloud solutions. An obvious question for me was that if some people use R-B s in software development, why doesn t everybody? There are limits to the tooling for some programming languages that mean R-Bs are difficult or impossible. But where creating an R-B is practical, why are they not used more widely? So, to your second question. There is another factor, which seems to be more about a lack of communication rather than neglecting opportunities. Businesses may not always be willing to discuss their development processes and innovations. Though I do think the increasing number of conferences (big and small) for software practitioners is helping to facilitate more communication and greater exchange of ideas.
Chris: Has your personal view of reproducible builds changed since before you embarked on writing this paper? Simon: Absolutely! In the early stages of the research, I was interested in questions of trust and how R-Bs were applied to resolve build and supply chain security problems. As the research developed, however, I started to see there were benefits to the use of R-Bs that were less obvious and that, in some cases, an R-B can have more than a single application.
Chris: Finally, do you have any plans to do future research touching on reproducible builds? Simon: Yes, definitely. There are a set of problems that interest me. One already mentioned is the use of reproducible builds with AI systems. Interpretable or explainable AI (XAI) is a necessity, and I think that R-Bs can be used to support traceability in the configuration and testing of both deployed systems and systems used during model training and evaluation. I would also like to return to a problem discussed briefly in the article, which is to develop a deeper understanding of the elements involved in the application of R-Bs that can be used to support reasoning about existing and potential applications of R-Bs. For example, R-Bs can be used to establish trust for different groups of individuals at different times, say, between remote developers prior to the release of software and by users after release. One question is whether when an R-B is used might be a significant factor. Another group of questions concerns the ways in which trust (of some sort) propagates among users of an R-B. There is an example in the paper of a company that rebuilds Debian reproducibly for security reasons and is then able to collaborate on software projects where software is built reproducibly with other companies that use public distributions of Debian.

Chris: Many thanks for this interview, Simon. If someone wanted to get in touch or learn more about you and your colleagues at the School of Informatics, where might they go? Thank you for the opportunity. It has been a pleasure to reflect a little more widely on the research! Personally, you can find out about my work on my official homepage and on my personal site. The software systems research group (SSRG) has a website, and the University of Sk vde s English language pages are also available. Chris: Many thanks for this interview, Simon!

For more information about the Reproducible Builds project, please see our website at reproducible-builds.org. If you are interested in ensuring the ongoing security of the software that underpins our civilisation and wish to sponsor the Reproducible Builds project, please reach out to the project by emailing contact@reproducible-builds.org.

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