Debian must ship reproducible packages

https://lists.debian.org/debian-devel-announce/2026/05/msg00001.html

by robalni • 2 months ago

372 166 2 months ago

lists.debian.org

blueflow• 2 months ago

zero improvement on end-user experience. does not solve supply chain issues, debian package will reproducabily contain the malware from upstream.

rlpb• 2 months ago

Debian has had a better "software supply chain" posture than any other player in the ecosystem since before the turn of the century. While we all face the risk of malware from upstream, Debian is the least at risk of being affected by it. See for example the stream of issues from npm et al. None of it has affected Debian.

alkindiffie• 2 months ago

for example the stream of issues from npm et al.

Curious, what distros where affected by npm supply chain attacks?

suprjami3• 2 months ago

You do remember the xz-utils backdoor was found in Sid right?

https://en.wikipedia.org/wiki/XZ_Utils_backdoor

iveqy• 2 months ago

It does not solve all supply chain issues, it do solve some supply chain issues.

Not being able to see if the source code shipped is the same as been used for creating the binary is scary

murderfs2• 2 months ago

Has there been a single publicly known attack that would have been prevented by this?

quantummagic• 2 months ago

zero improvement on end-user experience.

Maybe not by itself, but it does allow for the ecosystem to be audited, in a way that ultimately benefits the end-user. It really is an important part of a healthy supply chain.

PunchyHamster16• 2 months ago

no problem in Debian since the start of the effort would be solved by reproductible builds

This is nice pat yourself on the back achievement for people that prefer security theatre and checking boxes than doing something actually useful, and they wasted thousands man hours of poor victims that had to implement it

mschuster91• 2 months ago

That's not what reproducible builds aim to prevent, and no one claims that. When upstream pushes bad code, that's on upstream.

The thing reproducible builds aim to prevent is Debian or individual developers and system administrators with access rights to binary uploads and signing keys to get forced to sign and upload binary packages by attackers - be these governments (with or without court orders) or criminal organizations.

As of now, say if I were an administrator of Debian's CI infrastructure, technically there would be nothing preventing me from running an "extra" job on the CI infrastructure building a package for openssh with a knock-knock backdoor, properly signing it and uploading it to the repository. For someone to spot the attack and differentiate it, they'd have to notice that there is a package in the repository that has no corresponding build logs or has issues otherwise.

But with reproducible builds, anyone can set up infrastructure to rebuild Debian packages from source automatically and if there is a mismatch with what is on Debian's repository, raise alarm bells.

ownagefool• 2 months ago

Reproducible builds shows that, within a specific configuration, the code produced the binary, regardless of who signed or published it.

Indeed, this could mitigate an attacker replacing the binary with something that's not produced from the code, but it does not mitigate the tool chain or code itself containing the exploit, creating a malicious binary.

shevy-java2• 2 months ago

Well - reproducible also means code guarantee. It may not improve an end-user experience directly, but you get an extra quality control step, as guarantee, here. I think reproducibility is great. If we can achieve that, it should be achieved. See also NixOS; it can guarantee that snapshot xyz works, not just for one user, but ALL users. I see it as hopping from guarantee to guarantee. That's actually a good thing in the long run. Just think differently here.

hiAndrewQuinn• 2 months ago

This is some of the best news I've heard recently when it comes to figuring out how to produce high quality Software Bills of Materials for the upcoming EU Cyber Resilience Act, for what it's worth. Reproducible packages are actually worth a great deal when you are selling products with digital elements. Much easier to scan through, audit, etc. with confidence.

atoav• 2 months ago

If you find yourself holding opinions of the kind: "If it can't be made perfect, it shouldn't be changed at all?" you may want to consider that most things that work well today were incrementally improved.

Reproducable builds are not solving all issues as you rightly observed, but they can be a stepping stone (or even a pre-condition) for further measures.

otabdeveloper42• 2 months ago

zero improvement on end-user experience

The end-user experience is that now you can host your Debian binaries in caches and CDNs without worrying about supply chain hackers.

You can verify that file hashes match the ones on Debian's website and sleep much better at night.

If you don't trust Debian's website then you can rebuild yourself and check if Debian has been compromised.

tremon3• 2 months ago

You could already do that since Debian cryptographically signs all its package indexes, and the indexes contain the hash of all packages. The additional guarantee that reproducible builds bring is that you can re-build the packages in your own controlled environment and verify that the resulting package is bit-for-bit identical to what Debian offers.

MomsAVoxell13• 2 months ago

Who is this mythical end user? Reproducible builds are good for everyone - not just the average joe.

shevy-java2• 2 months ago

A small step for debian,

giant leap for mankind.

stingraycharles2• 2 months ago

As someone who recently spent a lot of time on making a large C++ program entirely reproducible on 4 different OS’es, one cannot understate just how many tiny details matter here.

gjvc• 2 months ago

"overstate"

jaypatelani• 2 months ago

Good thing. NetBSD has fully reproductible build since 2017. https://blog.netbsd.org/tnf/entry/netbsd_fully_reproducible_...

idoubtit• 2 months ago

As pointed in your link, NetBSD achieved this with some help from Debian. If I understand correctly, it's not that NetBSD tried harder, it's that their problem was easier: fewer packages which change less (they still use CVS, "stability" is an understatement!).

BTW, most Debian packages have reproducible builds. Those which have not (I'd say 5%) are shown in orange in the graph there: https://wiki.debian.org/ReproducibleBuilds

kakwa_2• 2 months ago

Also, the *BSD are structured somewhat differently to a Linux distro.

It's not like the Linux world where you have distinct projects like the Kernel, GNU, OpenSSL, and then it's the distributions job to assemble everything.

In the BSD projects, the scope is developing and distributing an entire base system, i.e., the kernel but also the libc, the shell/all posix utilities, and a few third parties like OpenSSH (which are usually "softforked").

It's quite visible in the sources, it's a lot more than just a kernel: https://github.com/NetBSD/src

Additional packages you could get from pkg_in/pkgsrc (NetBSD), pkg-ng/ports (FreeBSD) or pkg_add (OpenBSD) are clearly distinct from the base system, installed in a dedicated subtree (/usr/src in NetBSD, /usr/local/ OpenBSD/FreeBSD), and provided in a best effort manner.

The reproducible build target was almost certainly only for the base system, which is a few percent of what Debian tries to achieve, and on which NetBSD has a tighter control over (developer + distributor instead of downstream assembler+distributor).

A reproducible base system is useful, but given how quickly you typically need to install packages from pkgsrc, it's not quite enough.

mmooss2• 2 months ago

it's not that NetBSD tried harder, it's that their problem was easier: fewer packages which change less

Maybe that's trying harder on design rather than trying to remedy the consequences later.

lrvick2• 2 months ago

While we are bragging, stagex was the first to hit 100% full source bootstrapped deterministic and hermetic builds last year and the first to make multiple signed reproductions by different maintainers on their own hardware mandatory for every release.

Debian has come along way, but when Debian says reproducible they mean they grab third party binaries to build theirs. When we say reproducible we mean 100% bootstrapped from source code all the way through the entire software supply chain.

We think that distinction matters.

https://stagex.tools

PunchyHamster16• 2 months ago

That distro has smaller codebase than Debian Installer.

nrvn• 2 months ago

This!

Unfortunately, the term “reproducible” can be interpreted in many ways because there is no strict and complete definition. People and projects bend it to their liking.

Your approach is correct.

https://www.bootstrappable.org/

deknos5• 2 months ago

newcomers will always have it much easier. also guix i think also reached this.

also, stagex and others probably profited QUITE A LOT from the debian efforts, because they started to go upstream and talking to developers..

just arch linux profited from debian maintainers a decade before that an debian people asking upstream to improve...

matttttttttttt• 2 months ago

Stage -1: `hexdump`, `xxd`, or whatever you use to write files to your filesystem.

kkfx2• 2 months ago

Debian, like any other legacy distro, mush became declarative, because the '80s model of manual deploy and the absurd pain of D/I and Preseed must end.

kakwa_2• 2 months ago

In the end, Nix is just a thin veneer on this stuff.

Given how many quick & dirty sed patching or exec commands I've seen in the few nix package/modules I've read, I would not exactly bet my life on it being completely idempotent & reproducible.

kkfx2• 2 months ago

it's the best option after IllumOS (OpenSolaris) IPS integrated with ZFS. Far less powerful not imposing zfs (only well supported for root, swap, encryption etc), so not integrated in the package system and bootloader management (BEs, Boot Environments).

It's not reproducible bit by bit, it fetch the current version of anything, but it's still easy to reproduce enough, stable enough and complete enough, while classic distros need a fresh install every major release or facing issues an keeping a system in unknown state for long until it explode.

suprjami3• 2 months ago

bootcrew have bootc Containerfiles for Debian, Ubuntu, Arch, and openSUSE:

https://github.com/bootcrew/mono

farfatched4• 2 months ago

I've been 100% on NixOS on many years, but it's Debian that really drove this project.

They're still a pragmatic choice for many usecases.

Zopieux• 2 months ago

A great milestone, congrats Debian on taking a stance and holding high standards for yourself, especially in the current era.

inglor_cz• 2 months ago

Has anyone fought Microsoft Visual Studio successfully to produce reproducible builds of C++ programs? From what I have heard, it is one of the worst contexts to do it.

azkalam2• 2 months ago

Probably easiest way is to use Bazel to leverage the effort that has gone in there

einpoklum2• 2 months ago

Well, you can't build MSVS yourself, reproducibly or otherwise, so this is a less appealing endeavor I would think.

Dwedit2• 2 months ago

It's that RICH header that you need to exclude. I just tested my copy of MSVC 2019, and `/emittoolversioninfo:no` will exclude the RICH header from the binary. Supposedly also works in MSVC 2022.

The build timestamps in the PE header and export table are also a problem as well.

pixel_popping2• 2 months ago

Forbidden

You don't have permission to access this resource. Apache Server at lists.debian.org Port 443

ameliaquining• 2 months ago

I can see it just fine; maybe an overzealous firewall thinks you're a bot? At any rate, the Wayback Machine has it: https://web.archive.org/web/20260510074120/https://lists.deb...

baranul• 2 months ago

Unfortunately, many of these "protections" don't know what is a bot or a human. Many clueless websites are often just blocking huge swaths of legitimate readers and customers.

pixel_popping2• 2 months ago

Why would you block access to a static page, even Bots, what's the point? I'm not a bot, very typical non-privacy setup (Firefox, Linux, VPN) for personal usage.

It does work with my privacy/scrapping setup (residential proxy, spoofed fingerprints, Qubes and so on), great job debian.

perlgeek• 2 months ago

https://wiki.debian.org/ReproducibleBuilds has some more infos; some is outdated, but it also has a chart showing how many packages are built in the CI, and how many of those are reproducible builds.

(Orange = FTBR = "failed to build reproducibly")

I'm not good at reading numbers from charts, but I'd guess it's a few percent (4-5ish?).

bpavuk2• 2 months ago

all I get is this:

Forbidden
<p>You are not allowed to access this!</p>

(yes, with HTML tags on display) :)

EDIT: I also found a "I Challenge Thee" page in history. did I just get blocked by antibot measures? why???

unleaded• 2 months ago

Do you have JavaScript disabled? They put one of those anti-scraper things on it.

uecker7• 2 months ago

This is a huge achievement for Debian and the free software world.

It took a while though until this was understood. In 2007 when pointing out on debian-devel that this is needed, I was still told what huge waste of time this would be. And indeed it took a huge amount of work by many people to get there, but it is well worth it.

PunchyHamster16• 2 months ago

There was no bug or attack on Debian since 2007 that reproducible packages would prevent.

"Well worth it" is not correct. And it just ups the the contribution barrier to Debian higher, I already heard a lot of people complaining that contributing to Debian is hard and while in past I defended it by "they need all the checks and bounds to make sure packages play with eachother nicely", this is just step that makes it hard for no reason and little benefit.

aborsy• 2 months ago

There was perhaps no detected bug or attack. There have most likely been bugs or attacks that reproducible builds would have prevented.

savolai• 2 months ago

” If you are wondering why we are doing this at all, then hopefully the Reproducible Builds website will explain why this is useful.”

https://reproducible-builds.org/

Could you perhaps respond to the argumentation here?

azkalam2• 2 months ago

Reproducible builds reduce the need for trusted parties.

Have many organizations produce the binaries independently and post the arifacts.

Once n of m parties agree on the arifact hash, take that as the trusted build.

If every party reaches a different hash then we cannot build consensus.

eptcyka• 2 months ago

It makes shipping backdoors a whole lot harder, yes.

MomsAVoxell13• 2 months ago

Reproducible builds are applicable not only to respond to ‘attacks’, a subject you seem to be bikeshedding, but also for other reasons too.

Anyone having to maintain a code base or a distributed fleet of devices will gain from this decision, immensely, as their operational periods come and go.

Reproducible builds are about longevity as much as they are about security.

Please don’t make bold claims about ‘no reason and little benefit’ while demonstrating ignorance of this hard fact: reproducible builds should have been the norm, in computing, from the get-go.

benregenspan• 2 months ago

Is the "Jia Tan" XZ Utils compromise not a good example? That relied on code snuck into a release that was not in source.

(It was caught before being promoted into a stable Debian release, yes, but this sort of relied on a happy accident, too close for comfort)

deknos5• 2 months ago

"mimimimi".

Those people do not care about quality in opensource at all. For longliving software this is very important.

Of course, all those javascript and kubernetes packages which are irrelevant in a few years again, might complain, but let them complain.

ckastner3• 2 months ago

There was no bug or attack on Debian since 2007 that reproducible packages would prevent.

I'm reading this as a suggestion that the reproducible builds effort was an ineffective deterrent.

However, note that your observation could also be explained by the opposite: the reproducible builds effort was an effective deterrent, so nobody bothered with attempts.

And it just ups the the contribution barrier to Debian higher

Until yesterday, the package just got flagged in the tracker, and you could either ignore it, or fix it yourself, or the kind people behind the reproducible builds effort supplied a patch themselves.

Now, you can no longer ignore it. But fixes are often trivial. Use a (stable) timestamp provided by the build, seed RNGs with some constant (instead of eg: time), etc. These are best practices anyway.

charcircuit8• 2 months ago

So much time has been wasted on reproducible builds which could have better spent on securing more important parts of Debian. Practically minor changes like a build timestamp being different is not an issue.

Hendrikto3• 2 months ago

It allows verifying that the binaries actually match the source, which is extremely valuable.

charcircuit8• 2 months ago

Bit for bit matching is not required for that.

farfatched4• 2 months ago

Yes, making sure build timestamps are reproducible isn't a security win.

What is a win is that two independent parties can run the same build, and get the same binaries.

This is important because it removes trust from builders: anyone can verify their output.

It just so happens that unimportant things like build versions impede that.

charcircuit8• 2 months ago

Anyone can verify the actual code in the binary matches even if some bytes within the binary file itself are different. The verification routine doesn't have to be a basic bit for bit equality test.

deknos5• 2 months ago

you are free to provide patches instead of bitching.

charcircuit8• 2 months ago

And Debian is able to offer me a few million dollars yearly to help fix their security situation.

micw• 2 months ago

I wonder why this is a thing nowadays. I use yocto for embedded devices and it was almost a no-brainer to implement reproducible builds. I can also easily enable Debian package management, so everything is already available.

MomsAVoxell13• 2 months ago

What do you mean why is it a thing nowadays?

Reproducible builds are an essential method in industrial computing - Debian isn’t at the forefront of this, it is merely adopting industry wide techniques also applied to other operating systems in use in long-term and safety-related applications.

Certainly, a lot of the hard work of the Yocto and Debian developers is already in your hands.

What is interesting is that this is now being applied in a more forward-focused policy by the Debian developers, that it will now be the norm rather than an option…

dezgeg• 2 months ago

Did you actively verify that your builds were bit-reproducible?

einpoklum2• 2 months ago

Debian must ship packages without the hard dependence on systemd.

suprjami3• 2 months ago

I am always surprised Debian are leading this and not the commercial vendors. You'd think big organisations paying for RHEL and Ubuntu would be beating down the door for verifiable binaries.

tremon3• 2 months ago

If a competitor can prove that their packages are bit-for-bit identical to what a big organization is shipping, that allows the competitor to benefit from the security assurances of the big org. This is great for software freedom, not so great for wannabe monopolists.

jorams• 2 months ago

Reproducible builds exist to reduce the need for trust, while commercial vendors are in the business of selling trust.

Hendrikto3• 2 months ago

Why the fuck does that site break the back button? DO NOT do that.

em-bee• 2 months ago

since there is no other way to reach you please allow me to use this off topic message to let you know that there is a response to your comments on the gnupg discussion from two weeks ago.

TacticalCoder• 2 months ago

What people really don't understand about reproducible builds is that they're not a guarantee that there's no backdoor.

They're a guarantee that if there's a backdoor, it's reproducible 100% of the time.

This is a godsend for white hats fighting the good fight.

And, as a side note, it's strongarming vs the bad guys: "Would be too bad if we could reproduce your shiny exploit 100% of the time wouldn't it!?".

Note that we should go further (but it's a bit orthogonal to reproducible builds): builds of the final binary/package should happen by first entirely discarding all files not necessary for the final build (like all test cases and all test assets). The build should literally happen in an environment that gets rid of those (after, of course, having test in another environment that all tests cases succeed): if I'm not mistaken get rid of test assets would have stopped Jia Tan's XZ backdoor attempt dead in its track (for example). Because IIRC there were binary data part of the backdoor hidden in some asset only used by test cases.

P.S: as a bonus they also allow to detect bit-flips (I'm not saying there aren't other ways to detect bit-flips: what I'm saying is that if you have deterministic builds anyway and something doesn't reproduce correctly due to a flipped-bit, it's going to be noticed).

tofflos• 2 months ago

amd64 forky

reproduced: 97.02% good: 17586 bad: 511 fail: 30 unknown: 0

This, statistics for other architectures, and the reasons for unreproducibility can be found at https://reproduce.debian.net.

amelius• 2 months ago

That's cool but I'm honestly a bit disappointed in how apt refused to embrace/support both the container and AI/GPU aspects of computing. Are we going to see some changes there?

yjftsjthsd-h4• 2 months ago

Those seem like unrelated things? I can imagine ways for apt to integrate with containers, but what would it possibly do for AI or GPU other than delivering packages like it already does?

Arrowmaster• 2 months ago

What exactly are you talking about? Those don't seem related.

kkyktkrkekk• 2 months ago

”Optimize the code for 5 seconds”, as many compilers, including vc++ on windows did, was probably one of the dumbest thing ever invented. It meant that the binaries became more optimized when building on faster computers.

jgneff• 2 months ago

I'm so happy to see this change. I got involved with reproducible builds in 2021 after reading in horror about the SolarWinds attack. [1]

I think Magnus Ihse Bursie said it best while working on reproducible builds of OpenJDK: "If you were to ask me, the fact that compilers and build tools ever started to produce non-deterministic output has been a bug from day one." [2]

[1] https://www.linux.com/news/preventing-supply-chain-attacks-l...

[2] https://github.com/openjdk/jdk/pull/9152#issue-1270543997

rurban2• 2 months ago

... and most of this work is done by other distros and maintainers. Starting with binutils

casey2• 2 months ago

This fights against "opensource-washing" which is the practice of large companies claiming to release open source code, but the compile takes so long (as well as being overly-convoluted) that most people and many distros can't afford to maintain the package.

It feels like AI and traditional software are converging in complexity.

rurban2• 2 months ago

So these are broken on amd64. Debian arm64/forky rebuilderd stats https://reproduce.debian.net/arm64/stats/forky/

Most with failed to reproduce: NT_GNU_BUILD_ID. The others on some other bits. Mostly timestamps or hashes I assume

Debian must ship reproducible packages

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