From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: "Michael V. Scovetta" <michael.scovetta@gmail.com>,
Phillip Wood <phillip.wood@dunelm.org.uk>,
git@vger.kernel.org
Subject: Re: [PATCH] sequencer: detect author name errors in read_author_script()
Date: Mon, 03 Oct 2022 09:34:26 -0700 [thread overview]
Message-ID: <xmqq8rlwx3vx.fsf@gitster.g> (raw)
In-Reply-To: <YzqhEcTDwMwa8dQX@coredump.intra.peff.net> (Jeff King's message of "Mon, 3 Oct 2022 04:45:05 -0400")
Jeff King <peff@peff.net> writes:
> On Sun, Oct 02, 2022 at 11:39:16PM -0700, Michael V. Scovetta wrote:
>
>> In commit 2a7d63a2, sequencer.c:912 looks like:
>> 912 if (name_i == -2)
>> 913 error(_("missing 'GIT_AUTHOR_NAME'"));
>> 914 if (email_i == -2)
>> 915 error(_("missing 'GIT_AUTHOR_EMAIL'"));
>> 916 if (date_i == -2)
>> 917 error(_("missing 'GIT_AUTHOR_DATE'"));
>> 918 if (date_i < 0 || email_i < 0 || date_i < 0 || err) <-- date_i
>> is referenced here twice
>> 919 goto finish;
>>
>> I'm fairly sure that line 918 should be:
>> 918 if (name_i < 0 || email_i < 0 || date_i < 0 || err)
>
> Agreed, but +cc Phillip as the original author.
>
>> I haven't validated this, but I suspect that if
>> `rebase-merge/author-script` contained two GIT_AUTHOR_NAME fields,
>> then name_i would be set to -1 (by the error function), but control
>> wouldn't flow to finish, but instead to line 920 ( *name =
>> kv.items[name_i].util; ) where it would attempt to access memory
>> slightly outside of items' memory space.
>
> Correct. It also happens if GIT_AUTHOR_NAME is missing.
>
>> I haven't been able to actually trigger the bug, but strongly suspect
>> I'm just not familiar enough with how rebasing works under the covers.
>
> It's a little tricky, because we avoid writing and reading the
> author-script file unless necessary. An easy way to need it is to break
> with a conflict (which writes it), and then resume with "git rebase
> --continue" (which reads it back while committing).
>
> Here's a patch to fix it. Thanks for your report!
And thanks for your fix ;-)
next prev parent reply other threads:[~2022-10-03 16:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 6:39 Bug Report: Duplicate condition in read_author_script (sequencer.c) Michael V. Scovetta
2022-10-03 8:45 ` [PATCH] sequencer: detect author name errors in read_author_script() Jeff King
2022-10-03 9:29 ` Phillip Wood
2022-10-03 17:15 ` Jeff King
2022-10-03 9:40 ` Ævar Arnfjörð Bjarmason
2022-10-03 17:27 ` Jeff King
2022-10-03 17:39 ` Jeff King
2022-10-03 18:05 ` Junio C Hamano
2022-10-03 16:34 ` Junio C Hamano [this message]
2022-10-03 17:35 ` Jeff King
2022-10-03 18:07 ` Junio C Hamano
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