OpenPGP key expiration is not a security measure

There seems to be some recurring confusion among Gentoo developers regarding the topic of OpenPGP key expiration dates. Some developers seem to believe them to be some kind of security measure — and start arguing about its weaknesses. Furthermore, some people seem to think of it as rotation mechanism, and believe that they are expected to generate new keys. The truth is, expiration date is neither of those.

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Inlining path_exists

The path_exists function in eutils was meant as a simple hack to check for existence of files matching a wildcard. However, it was kinda ugly and never became used widely. At this very moment, it is used correctly in three packages, semi-correctly in one package and totally misused in two packages. Therefore, I think it’s time to replace it with something nicer.

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Verifying repo/gentoo.git with gverify

Git commit signatures are recursive by design — that is, each signature covers not only the commit in question but also indirectly all past commits, via tree and parent commit hashes. This makes user-side commit verification much simpler, as the user needs only to verify the signature on the most recent commit; with the assumption that the developer making it has verified the earlier commit and so on. Sadly, this is usually not the case at the moment.

Most of the Gentoo developers do not really verify the base upon which they are making their commits. While they might verify the commits when pulling before starting to work on their changes, it is rather unlikely that they verify the correctness when they repeatedly need to rebase before pushing. Usually this does not cause problems as Gentoo Infrastructure is verifying the commit signatures before accepting the push. Nevertheless, the recent attack on our GitHub mirrors made me realize that if a smart attacker was able to inject a single malicious commit without valid signature, then a Gentoo developer would most likely make a signed commit on top of it without even noticing the problem.

In this article, I would like to shortly present my quick solution to this problem — app-portage/gverify. gverify is a trivial reimplementation of gkeys in <200 lines of code. It uses the gkeys seed data (yes, this means it relies on manual updates) combined with autogenerated developer keyrings to provide strict verification of commits. Unlike gkeys, it works out-of-the-box without root privileges and automatically updates the keys on use.

The package installs a gv-install tool that installs two hooks on your repo/gentoo.git working copy. Those are post-merge and pre-rebase hooks that verify the tip of upstream master branch, respectively every time merge on master is finished, and every time a rebase is about to be started. This covers the two main cases — git pull and git pull --rebase. The former causes a verbose error after the update, the latter prevents a rebase from proceeding.

While this is far from perfect, it seems reasonably good solution given the limitations of available git hooks. Most importantly, it should prevent the git pull --rebase -S && git push --sign loop from silently accepting a malicious commit. Currently the hook verifies the top upstream commit only; however, in the future I want to implement incremental verification of all new commits.

The story of Gentoo management

I have recently made a tabular summary of (probably) all Council members and Trustees in the history of Gentoo. I think that this table provides a very succinct way of expressing the changes within management of Gentoo. While it can’t express the complete history of Gentoo, it can serve as a useful tool of reference.

What questions can it answer? For example, it provides an easy way to see how many terms individuals have served, or how long Trustee terms were. You can clearly see who served both on the Council and on the Board and when those two bodies had common members. Most notably, it collects a fair amount of hard-to-find data in a single table.

Can you trust it? I’ve put an effort to make the developer lists correct but given the bad quality of data (see below), I can’t guarantee complete correctness. The Trustee term dates are approximate at best, and oriented around elections rather than actual term (which is hard to find). Finally, I’ve merged a few short-time changes such as empty seats between resignation and appointing a replacement, as expressing them one by one made little sense and would cause the tables to grow even longer.

This article aims to be the text counterpart to the table. I would like to tell the history of the presented management bodies, explain the sources that I’ve used to get the data and the problems that I’ve found while working on it.

As you could suspect, the further back I had to go, the less good data I was able to find. The problems included the limited scope of our archives and some apparent secrecy of decision-making processes at the early time (judging by some cross-posts, the traffic on -core mailing list was significant, and it was not archived before late 2004). Both due to lack of data, and due to specific interest in developer self-government, this article starts in mid-2003.

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Empty directories, *into, dodir, keepdir and tmpfiles.d

There seems to be some serious confusion around the way directories are installed in Gentoo. In this post, I would like to shortly explain the differences between different methods of creating directories in ebuilds, and instruct how to handle the issues related to installing empty directories and volatile locations.

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