Re: [PATCH 1/2] gpg-interface: handle missing " with " gracefully in parse_ssh_output()
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Nov 1, 2021, 06:08 UTC
- Message-ID
- <xmqqy268csrx.fsf@gitster.g>
- In-Reply-To
- <f6fca7c0-079c-4337-23d9-cd970c79b8ad@web.de>
René Scharfe <l.s.r@web.de> writes:
Show 9 quoted lines
> 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.
Show 34 quoted lines
>
> 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