On Mon, Apr 9, 2018 at 4:41 PM, Ben Toews <[email protected]> wrote:
> From: Jeff King <[email protected]>
>
> A signed tag has a detached signature like this:
>
> object ...
> [...more header...]
>
> This is the tag body.
>
> -----BEGIN PGP SIGNATURE-----
> [opaque gpg data]
> -----END PGP SIGNATURE-----
>
> Our parser finds the _first_ line that appears to start a
> PGP signature block, meaning we may be confused by a
> signature (or a signature-like line) in the actual body.
> Let's keep parsing and always find the final block, which
> should be the detached signature over all of the preceding
> content.
> ---
> diff --git a/gpg-interface.c b/gpg-interface.c
> @@ -110,11 +110,17 @@ static int is_gpg_start(const char *line)
> size_t parse_signature(const char *buf, size_t size)
> {
> size_t len = 0;
> - while (len < size && !is_gpg_start(buf + len)) {
> - const char *eol = memchr(buf + len, '\n', size - len);
> + size_t match = size;
If no GPG-start line is found then 'size' will be returned, which
matches the logic before this change. Okay.
> + while (len < size) {
> + const char *eol;
> +
> + if (is_gpg_start(buf + len))
> + match = len;
Otherwise, the position of the final GPG-start line will be remembered
and returned. Makes sense.
> + eol = memchr(buf + len, '\n', size - len);
> len += eol ? eol - (buf + len) + 1 : size - len;
> }
> - return len;
> + return match;
> }
> diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
> @@ -1059,6 +1059,17 @@ test_expect_success GPG \
> +test_expect_success GPG 'signed tag with embedded PGP message' '
> + cat >msg <<-\EOF &&
> + -----BEGIN PGP MESSAGE-----
> +
> + this is not a real PGP message
> + -----END PGP MESSAGE-----
> + EOF
This bogus PGP message is just in the body...
> + git tag -s -F msg confusing-pgp-message &&
and "git tag -s" adds the real PGP message at the end...
> + git tag -v confusing-pgp-message
and the new logic finds the real PGP message rather than the bogus
one, so "git tag -v" exits successfully. Looks good.
> +'
