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authorLudovic Courtès <ludo@gnu.org>2022-01-28 17:20:43 +0100
committerLudovic Courtès <ludo@gnu.org>2022-02-14 11:23:08 +0100
commitca87601dd97dd9d356409827802eb0f8a3a535f0 (patch)
treee3a6c9e4abb95e45c27aa80dcdc9d99a2f661a6e /doc
parent87d49346f3072f7b4343b6fb387ee5f9311493b7 (diff)
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.
Diffstat (limited to 'doc')
-rw-r--r--doc/guix.texi4
1 files changed, 3 insertions, 1 deletions
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}