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Bug 676262 - <dev-vcs/git-2.20: multiple commit signatures can cause confusing %GK/%GS output
Summary: <dev-vcs/git-2.20: multiple commit signatures can cause confusing %GK/%GS output
Status: IN_PROGRESS
Alias: None
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Security
URL: https://dev.gentoo.org/~mgorny/articl...
Whiteboard: A4 [glsa+ cleanup]
Keywords: STABLEREQ
Depends on:
Blocks:
 
Reported: 2019-01-26 10:31 UTC by Michał Górny
Modified: 2019-08-12 23:18 UTC (History)
3 users (show)

See Also:
Package list:
dev-vcs/git-2.21.0
Runtime testing required: Yes


Attachments

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Description Michał Górny archtester Gentoo Infrastructure gentoo-dev Security 2019-01-26 10:31:33 UTC
This is something I've discovered back in August 2018.  Fix is included in 2.20.0.

Long story short, if you take a commit with good signature, alter its contents and then add an additional untrusted signature, you end up with two signatures: one BAD signature made with trusted key, and GOOD signature made with other key.  Git format strings may end up reporting it as %G? = U (untrusted) with %GK/%GS listing the *trusted* key (taken from BAD signature).

This shouldn't affect normal git use or the tools used normally by Gentoo.  However, some poorly written verification script may be tricked into believing it got a commit with good signature from trusted key (if it assumes %G? = U is normal, and then verifies correctness via %GK).
Comment 1 Aaron Bauman Gentoo Infrastructure gentoo-dev Security 2019-03-29 20:33:51 UTC
@arches, please stabilize.
Comment 2 Mikle Kolyada archtester Gentoo Infrastructure gentoo-dev Security 2019-03-29 21:53:59 UTC
amd64 stable
Comment 3 Mikle Kolyada archtester Gentoo Infrastructure gentoo-dev Security 2019-03-30 19:02:19 UTC
arm stable
Comment 4 Thomas Deutschmann gentoo-dev Security 2019-04-02 01:38:53 UTC
x86 stable
Comment 5 Mikle Kolyada archtester Gentoo Infrastructure gentoo-dev Security 2019-04-06 13:41:35 UTC
alpha stable
Comment 6 Sergei Trofimovich gentoo-dev 2019-04-07 21:43:38 UTC
ia64 stable
Comment 7 Sergei Trofimovich gentoo-dev 2019-04-07 21:49:35 UTC
ppc64 stable
Comment 8 Mikle Kolyada archtester Gentoo Infrastructure gentoo-dev Security 2019-04-07 21:58:06 UTC
s390 stable
Comment 9 Sergei Trofimovich gentoo-dev 2019-04-08 06:10:03 UTC
ppc stable
Comment 10 Aaron Bauman Gentoo Infrastructure gentoo-dev Security 2019-04-09 13:52:13 UTC
arm64 stable
Comment 11 GLSAMaker/CVETool Bot gentoo-dev 2019-04-11 01:16:28 UTC
This issue was resolved and addressed in
 GLSA 201904-13 at https://security.gentoo.org/glsa/201904-13
by GLSA coordinator Aaron Bauman (b-man).
Comment 12 Aaron Bauman Gentoo Infrastructure gentoo-dev Security 2019-04-11 01:17:10 UTC
re-opened for final arches and cleanup
Comment 13 Rolf Eike Beer 2019-04-11 19:42:04 UTC
sparc finished
Comment 14 Rolf Eike Beer 2019-04-23 21:22:01 UTC
hppa stable
Comment 15 Aaron Bauman Gentoo Infrastructure gentoo-dev Security 2019-08-12 23:18:42 UTC
Just waiting on sh, which is not a stable arch, for cleanup to happen...