What's the importance of reproducible builds?
Edit: found this nice overview by clicking a few links from the original post https://reproducible-builds.org/
Edit: found this nice overview by clicking a few links from the original post https://reproducible-builds.org/
It would be a lot of work but could expose malicious providers.
Then again it might be hard to create an actual good environment considering all the software /firmware/hardware layers modern systems have.
There is still work to be done, but NYU was one of the organizations working on developing and running a rebuilder. The idea is that you pull buildinfo files from https://buildinfo.debian.net/, then try to verify them and if you got the same artifact you sign that you successfully verified this binary package.
A user could then configure "I trust rebuilder X, Y, Z and I require that at least N have successfully verified the package" before installing it.
if I cant run the build process, and I dont really know which patch sets have been applied on my system, and which version of the source was used, and I dont really have a handle on the dependencies. doesn't make it substantially more difficult to debug and work with the resulting system?
its really quite odd that the dominant open source platform settled on opaque and unreproducible binaries as the distribution mechanism early on.
It's not that odd. Reproducible builds are very hard. "gcc foo.c -o foo" is very easy.
> its really quite odd that the dominant open source platform settled on opaque and unreproducible binaries as the distribution mechanism early on
It was perfectly logical when I was installing slackware from floppies, and it remains more useful in most use cases - smaller downloads that installed faster. Debian's great innovation was dependency management of binary packages, after all.
and I agree that installing linux as a binary makes sense. but people didn't think it was important to maintain the reference back to the actual source used. I think to some extent (RedHat specifically), the patch sets used and the hidden build process was used to make it less trivial to reproduce.
apt source htop
apt build-dep htop
cd htop-2.0.2
dpkg-buildpackage -us -uc -ncSeriously, this is nit picking, and you seem to acknowledge that here by using the term "less trivial". Instead of "tar -x" you run "rpmbuild -bp" to get the patched source RedHat will unleash the compiler on. For debian its "dpkg-source -x". I'm not even sure that it could be called "less trivial".
Getting hold of the source in the first place it looks to be "more trivial" to me as there is no Wumpus hunt to find the URL. For Debian it's just "apt-get source package-name". The RedHat equivalent is "yumdownloader --source". In both cases that gets you the exact source used to build the binary on your machine. I don't know what you would call a strong reference back to the actual source used, but I'm struggling to see how it could be much stronger.
As for the "hidden build process": it's only hidden because it's automated. You may as well be blaming "make" for hiding the kernel build process, which is more complex than most distro package builds. But every step the distro build processes (any distro) can be made very visible, naturally enough because otherwise it would be impossible to debug when things go wrong. And there is excellent doco on how to do all of this for both Red Hat and Debian.
linux distributions were designed around the model of binary-only proprietary "unix" that just happened to have also have source available as a bonus instead of comprising a fully self-hosting source+binaries+documentation system like research unix and source-available derivatives/patchsets (like bsd, etc) always were from day 1
My personal opinion is that unix is a culture and not a trademark, the culture is the users and systems based around this self-hosting system with source lineage back to the original. Binary unix-derived distributions (and unix clones like linux) are therefore implicitly not unix since they are not out of the box self hosting and source included to one degree or another, and do not have a direct code lineage back to at&t v7. At best, they are some approximation of 'unix like', which can still of course be pretty useful.
What is hard is too reproduce binaries that are byte-for-byte identical. This is not really needed to debug or work with a system, but needed for security to assure that no-one has meddled with the binary.
If you think source package distribution are more useful than binary distribution, then Gentoo Linux is still a viable option.
The problem that reproducible builds is attempting to solve is that my build, while being 100% functional, might not be bit identical to yours or what shipped with the distro for any number of valid reasons.[2] The problem this creates given the current world of increasingly sophisticated malware is that I can't prove a given build is identical to what was intended based on the binaries. So it's an issue of 'we've always been giving you the source, now we're going to ensure that it's possible to create bit-identical binaries' rather than 'we were giving you free binaries, now we're giving you the source'.
If your argument is that one should always build from source, reproducible builds is part of getting to the same effective result without the overhead and headache that the vast majority of users are not willing to deal with.
[1] In the cases when this turned out not to be possible, holy hell tends to get raised... see things like the Chromium BLOB issues (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786909) etc. These issues tend to have a lot of noise made and get resolved very quickly since it goes against the very core of what Debian is intended to be. In cases where you have things that are binary-only such as proprietary GPU drivers, these get segregated into a separate repo with the general advice from Debian of 'you shouldn't use these'. This doesn't tend to be realistic advice for many users given the state of many of the open source drivers... but they've tried their best to steer people away while not making the distro unusable for those who insist on using them.
[2] A trivial example would be baking the build date/machine name into the binary... there's no expectation that one would ever reproduce that build again even on the same machine.
For example if I'm reporting a bug and I have a proposed patch, it would be nice to be able to say "I've been running with this patch for the last month and it's been fine".
Ideally there'd be a coherent way to download the source for a particular package, rebuild it, and have the system use the rebuilt result. Bonus marks if it did something useful when a newer version of the package came along.
I think https://packages.debian.org/sid/dgit is an attempt to make the download-and-rebuild part look more uniform, but I think there's still work to be done to make it easy to substitute the result for the distro package.
You can also host this somewhere so others can run/test your modified version easily. No real special infrastructure required they can sync this directory via git.
There are of course downsides. The annoyance of building updates and discovering bugs not discovered by others by some unique set of patches / build time options.
But yeah, I noticed that Debian is not going out of its way to advertise one blessed solution.
- coping with the variety of different patch systems used in Debian packages
- an integrated way of keeping track of which locally-built packages have been installed
Also of course getting pbuilder set up, and knowing that it's an option in the first place.
In an ideal world I'd like to be able to say that the only knowledge you need to modify one of the programs on your system is the language that the program is written in, rather than having to also fill your head with bits of distro-specific arcana.
I do think that things are better than they were even a few years ago (in particular, the variety-of-different-patch-systems situation is getting noticeably better).
2) There isn't really difference between locally built packages and ones from the distro, but one way to distinguish yours is to append a suffix to your versions, e.g. andrewshX in my case, where X is an incrementing number.
This I find especially moronic. A deterministic build would have provided a perfect way to trace back a binary to it's sources/source commit, but let's give that up and trade it for a date and the hostname of the build machine :/
But binary distributions are just convenient. Even MCC was a binary distribution and that's going a long way back. I remember rebuilding everything by hand because I wanted a lean system that included exactly what I wanted and nothing more, but that was considered pretty extreme even at that time.
One of the problems with having the flexibility of a pure source based system (including being about to recompile with exactly the flags and hence features you want) is making a decent dependency graph. If you install package X and it wants capability A, it's practically impossible to guarantee that it will "all just work" because the user can easily screw it up. In many ways, this was one of the problems with Gentoo (apart from it being unreasonable these days to keep a complete system up to date while recompiling every single package -- it just takes too much time).
Of course Gentoo (and derivatives) have binary packages these days as well. I've moved over to Arch which has very minimal configuration for packages and so you have to take responsibility for making everything work. You can easily build things and the build scripts make it very easy to see what patches, etc you are using. However, its a lot more work than most people want.
I think the reality of the situation is that most people do no debug their systems. They just use it. If it is "broken" then they complain that it is "broken" and wait for someone to fix it. Actually maintaining your system is akin to working on hotrods in your garage. It's mostly a hobby, even for professionals.
So, best use of time would be one of three activities:
1. Gradually rewriting apps or kernels in safe languages. Can even make stuff reproducible as a side effect of rewrites.
2. Improving tools like SAFEcode snd Softbound+CETS that make C code safe. Esp usability and packaging. If not that, then more mitigations in OS like OpenBSD does. Can even port theirs.
3. Running static analyzers, fuzzers, etc on all that code out there. Then, fixing the vulnerabilities. Id say prioritize highly-priveleged and newest code.
That would actually improve the security of Debian against the kind of attacks that hit it the most. There's some people doing this. Not enough by far.