From: Junio C Hamano <gitster@pobox.com>
To: "René Scharfe" <l.s.r@web.de>
Cc: Git List <git@vger.kernel.org>, Fabian Stelzer <fs@gigacodes.de>
Subject: Re: [PATCH 1/2] gpg-interface: handle missing " with " gracefully in parse_ssh_output()
Date: Sun, 31 Oct 2021 23:08:18 -0700 [thread overview]
Message-ID: <xmqqy268csrx.fsf@gitster.g> (raw)
In-Reply-To: <f6fca7c0-079c-4337-23d9-cd970c79b8ad@web.de> ("René Scharfe"'s message of "Sat, 30 Oct 2021 19:04:56 +0200")
René Scharfe <l.s.r@web.de> writes:
> If the output of ssh-keygen starts with "Good \"git\" signature for ",
> but is not followed by " with " for some reason, then parse_ssh_output()
> uses -1 as the len parameter of xmemdupz(), which in turn will end the
> program. Reject the signature and carry on instead in that case.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
> This code was added after v2.33.0.
> Patch formatted with --inter-hunk-context=2 for easier review.
Nice spotting.
> Silly bonus question: What's the purpose of the "+ 1" and "- 1", which
> seem to cancel each other out?
Fabian, we are in -rc phase where we concentrate on fixing bugs in
the new code in 'master'. A quick ack, "here is a better way to fix
it", or "no, that won't be needed because..." is very much
appreciated.
Thanks.
>
> gpg-interface.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/gpg-interface.c b/gpg-interface.c
> index 800d8caa67..62d340e78a 100644
> --- a/gpg-interface.c
> +++ b/gpg-interface.c
> @@ -387,17 +387,19 @@ static void parse_ssh_output(struct signature_check *sigc)
> line = to_free = xmemdupz(sigc->output, strcspn(sigc->output, "\n"));
>
> if (skip_prefix(line, "Good \"git\" signature for ", &line)) {
> - /* Valid signature and known principal */
> - sigc->result = 'G';
> - sigc->trust_level = TRUST_FULLY;
> -
> /* Search for the last "with" to get the full principal */
> principal = line;
> do {
> search = strstr(line, " with ");
> if (search)
> line = search + 1;
> } while (search != NULL);
> + if (line == principal)
> + goto cleanup;
> +
> + /* Valid signature and known principal */
> + sigc->result = 'G';
> + sigc->trust_level = TRUST_FULLY;
> sigc->signer = xmemdupz(principal, line - principal - 1);
> } else if (skip_prefix(line, "Good \"git\" signature with ", &line)) {
> /* Valid signature, but key unknown */
> --
> 2.33.1
next prev parent reply other threads:[~2021-11-01 6:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-30 17:04 [PATCH 1/2] gpg-interface: handle missing " with " gracefully in parse_ssh_output() René Scharfe
2021-10-30 17:07 ` [PATCH 2/2] gpg-interface: avoid buffer overrun " René Scharfe
2021-11-01 6:07 ` Junio C Hamano
2021-11-01 8:33 ` Fabian Stelzer
2021-11-01 17:44 ` Junio C Hamano
2021-11-01 6:08 ` Junio C Hamano [this message]
2021-11-01 8:40 ` [PATCH 1/2] gpg-interface: handle missing " with " gracefully " Fabian Stelzer
2021-11-01 18:36 ` René Scharfe
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