[PATCH v2 2/3] commit: refactor verify_commit_buffer()
- From
Christian Couder <christian.couder@gmail.com>
- Date
- Nov 17, 2025, 04:34 UTC
- Message-ID
- <20251117043450.322644-3-christian.couder@gmail.com>
- In-Reply-To
- <20251117043450.322644-1-christian.couder@gmail.com>
In a following commit, we are going to check commit signatures, but we won't have a commit yet, only a commit buffer, and we are going to discard this commit buffer if the signature is invalid. So it would be wasteful to create a commit that we might discard, just to be able to check a commit signature.
It would be simpler instead to be able to check commit signatures using only a commit buffer instead of a commit.
To be able to do that, let's extract some code from the check_commit_signature() function into a new verify_commit_buffer() function, and then let's make check_commit_signature() call verify_commit_buffer().
Note that this doesn't fundamentally change how check_commit_signature() works. It used to call parse_signed_commit() which calls repo_get_commit_buffer(), parse_buffer_signed_by_header() and repo_unuse_commit_buffer(). Now these 3 functions are called directly by verify_commit_buffer().
Signed-off-by: Christian Couder <chriscool@tuxfamily.org> --- commit.c | 17 +++++++++++++++-- commit.h | 7 +++++++ 2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/commit.c b/commit.c index 16d91b2bfc..709c9eed58 100644 --- a/commit.c +++ b/commit.c @@ -1315,7 +1315,8 @@ static void handle_signed_tag(const struct commit *parent, struct commit_extra_h free(buf); } -int check_commit_signature(const struct commit *commit, struct signature_check *sigc) +int verify_commit_buffer(const char *buffer, size_t size, + struct signature_check *sigc) { struct strbuf payload = STRBUF_INIT; struct strbuf signature = STRBUF_INIT; @@ -1323,7 +1324,8 @@ int check_commit_signature(const struct commit *commit, struct signature_check * sigc->result = 'N'; - if (parse_signed_commit(commit, &payload, &signature, the_hash_algo) <= 0) + if (parse_buffer_signed_by_header(buffer, size, &payload, + &signature, the_hash_algo) <= 0) goto out; sigc->payload_type = SIGNATURE_PAYLOAD_COMMIT; @@ -1337,6 +1339,17 @@ int check_commit_signature(const struct commit *commit, struct signature_check * return ret; } +int check_commit_signature(const struct commit *commit, struct signature_check *sigc) +{ + unsigned long size; + const char *buffer = repo_get_commit_buffer(the_repository, commit, &size); + int ret = verify_commit_buffer(buffer, size, sigc); + + repo_unuse_commit_buffer(the_repository, commit, buffer); + + return ret; +} + void verify_merge_signature(struct commit *commit, int verbosity, int check_trust) { diff --git a/commit.h b/commit.h index 1d6e0c7518..5406dd2663 100644 --- a/commit.h +++ b/commit.h @@ -333,6 +333,13 @@ int remove_signature(struct strbuf *buf); */ int check_commit_signature(const struct commit *commit, struct signature_check *sigc); +/* + * Same as check_commit_signature() but accepts a commit buffer and + * its size, instead of a `struct commit *`. + */ +int verify_commit_buffer(const char *buffer, size_t size, + struct signature_check *sigc); + /* record author-date for each commit object */ struct author_date_slab; void record_author_date(struct author_date_slab *author_date,
-- 2.52.0.rc2.6.g1f299c9613