gpg-interface: remove other signature headers before verifying

When we have a multiply signed commit, we need to remove the signature
in the header before verifying the object, since the trailing signature
will not be over both pieces of data.  Do so, and verify that we
validate the signature appropriately.

Signed-off-by: brian m. carlson <>
Signed-off-by: Junio C Hamano <>
This commit is contained in:
brian m. carlson 2021-02-11 02:08:06 +00:00 committed by Junio C Hamano
parent 88bce0e24c
commit 9b27b49240
2 changed files with 27 additions and 0 deletions

View File

@ -1,4 +1,5 @@
#include "cache.h"
#include "commit.h"
#include "config.h"
#include "run-command.h"
#include "strbuf.h"
@ -366,6 +367,7 @@ int parse_signature(const char *buf, size_t size, struct strbuf *payload, struct
size_t match = parse_signed_buffer(buf, size);
if (match != size) {
strbuf_add(payload, buf, match);
strbuf_add(signature, buf + match, size - match);
return 1;

View File

@ -17,6 +17,13 @@ tag_exists () {
git show-ref --quiet --verify refs/tags/"$1"
test_expect_success 'setup' '
test_oid_cache <<-EOM
othersigheader sha1:gpgsig-sha256
othersigheader sha256:gpgsig
test_expect_success 'listing all tags in an empty tree should succeed' '
git tag -l &&
git tag
@ -1371,6 +1378,24 @@ test_expect_success GPG \
'test_config gpg.program echo &&
test_must_fail git tag -s -m tail tag-gpg-failure'
# try to produce invalid signature
test_expect_success GPG 'git verifies tag is valid with double signature' '
git tag -s -m tail tag-gpg-double-sig &&
git cat-file tag tag-gpg-double-sig >tag &&
othersigheader=$(test_oid othersigheader) &&
sed -ne "/^\$/q;p" tag >new-tag &&
cat <<-EOM >>new-tag &&
$othersigheader -----BEGIN PGP SIGNATURE-----
sed -e "1,/^tagger/d" tag >>new-tag &&
new_tag=$(git hash-object -t tag -w new-tag) &&
git update-ref refs/tags/tag-gpg-double-sig $new_tag &&
git verify-tag tag-gpg-double-sig &&
git fsck
# try to sign with bad user.signingkey
test_expect_success GPGSM \
'git tag -s fails if gpgsm is misconfigured (bad key)' \