From: Phillip Wood <phillip.wood123@gmail.com>
To: Gregory David <gregory.david@p1sec.com>, git@vger.kernel.org
Cc: ptm-dev <ptm-dev@p1sec.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH] show-branch: fix SEGFAULT when `--current` and `--reflog` together
Date: Wed, 20 Apr 2022 11:04:11 +0100 [thread overview]
Message-ID: <0825f153-1d03-feb4-1e34-4aaed766deb0@gmail.com> (raw)
In-Reply-To: <a36fd2b0-0573-b93e-a765-ce57a651934e@p1sec.com>
Hi Gregory
Thanks for working on this
On 19/04/2022 17:32, Gregory David wrote:
> If run `show-branch` with `--current` and `--reflog` simultaneously, a
> SEGFAULT appears.
>
> The bug is that we read over the end of the `reflog_msg` array after
> having `append_one_rev()` for the current branch without supplying a
> convenient message to it.
>
> It seems that it has been introduced in:
> Commit 1aa68d6735 (show-branch: --current includes the current branch.,
> 2006-01-11)
>
> Signed-off-by: Gregory DAVID <gregory.david@p1sec.com>
> Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
> builtin/show-branch.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/builtin/show-branch.c b/builtin/show-branch.c
> index e12c5e80e3..892241ce0d 100644
> --- a/builtin/show-branch.c
> +++ b/builtin/show-branch.c
> @@ -812,6 +812,26 @@ int cmd_show_branch(int ac, const char **av, const
> char *prefix)
> }
> if (!has_head) {
> const char *name = head;
> + struct object_id oid;
> + char *ref;
> + unsigned int flags = 0;
> + char *log_msg;
> + char *end_log_msg;
> + timestamp_t timestamp;
> + int tz;
> +
> + if (!dwim_ref(*av, strlen(*av), &oid, &ref, 0))
> + die(_("no such ref %s"), *av);
> + if(read_ref_at(get_main_ref_store(the_repository),
> + ref, flags, 0, i, &oid, &log_msg,
> + ×tamp, &tz, NULL)) {
> + end_log_msg = strchr(log_msg, '\n');
> + if (end_log_msg)
> + *end_log_msg = '\0';
> + }
> + if(log_msg == 0 || *log_msg == '\0')
> + log_msg = xstrfmt("(none)");
> + reflog_msg[ref_name_cnt] = xstrfmt("(%s) (current) %s",
Do we need a bounds check here? I think we're only guaranteed that
ref_name_cnt - 1 < MAX_REVS though I found the existing code a bit hard
to follow
Best Wishes
Phillip
> show_date(timestamp, tz, DATE_MODE(RELATIVE)), log_msg);
> skip_prefix(name, "refs/heads/", &name);
> append_one_rev(name);
> }
next prev parent reply other threads:[~2022-04-20 10:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 16:32 [PATCH] show-branch: fix SEGFAULT when `--current` and `--reflog` together Gregory David
2022-04-19 20:49 ` Ævar Arnfjörð Bjarmason
2022-04-20 10:04 ` Phillip Wood [this message]
2022-04-21 13:34 Gregory David
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