From ca87601dd97dd9d356409827802eb0f8a3a535f0 Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Fri, 28 Jan 2022 17:20:43 +0100 Subject: git-authenticate: Ensure the target is a descendant of the introductory commit. Fixes a bug whereby authentication of a commit *not* descending from the introductory commit could succeed, provided the commit verifies the authorization invariant. In the example below, A is a common ancestor of the introductory commit I and of commit X. Authentication of X would succeed, even though it is not a descendant of I, as long as X is authorized according to the '.guix-authorizations' in A: X I \ / A This is because, 'authenticate-repository' would not check whether X descends from I, and the call (commit-difference X I) would return X. In practice that only affects forks because it means that ancestors of the introductory commit already contain a '.guix-authorizations' file. * guix/git-authenticate.scm (authenticate-repository): Add call to 'commit-descendant?'. * tests/channels.scm ("authenticate-channel, not a descendant of introductory commit"): New test. * tests/git-authenticate.scm ("authenticate-repository, target not a descendant of intro"): New test. * tests/guix-git-authenticate.sh: Expect earlier test to fail since 9549f0283a78fe36f2d4ff2a04ef8ad6b0c02604 is not a descendant of $intro_commit. Add new test targeting an ancestor of the introductory commit, and another test targeting the v1.2.0 commit. * doc/guix.texi (Specifying Channel Authorizations): Add a sentence. --- doc/guix.texi | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'doc') diff --git a/doc/guix.texi b/doc/guix.texi index 86dbe9f201..c116be8907 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -5448,7 +5448,9 @@ commit of a channel that should be authenticated. The first time a channel is fetched with @command{guix pull} or @command{guix time-machine}, the command looks up the introductory commit and verifies that it is signed by the specified OpenPGP key. From then on, it -authenticates commits according to the rule above. +authenticates commits according to the rule above. Authentication fails +if the target commit is neither a descendant nor an ancestor of the +introductory commit. Additionally, your channel must provide all the OpenPGP keys that were ever mentioned in @file{.guix-authorizations}, stored as @file{.key} -- cgit v1.2.3