[PATCH v5 2/3] gpg-interface: allow sign_buffer() to use default signing key
- From
Justin Tobler <jltobler@gmail.com>
- Date
- Mar 12, 2026, 19:22 UTC
- Message-ID
- <20260312192228.481134-3-jltobler@gmail.com>
- In-Reply-To
- <20260312192228.481134-1-jltobler@gmail.com>
The `sign_commit_to_strbuf()` helper in "commit.c" provides fallback logic to get the default configured signing key when a key is not provided and handles generating the commit signature accordingly. This signing operation is not really specific to commits as any arbitrary buffer can be signed. Also, in a subsequent commit, this same logic is reused by git-fast-import(1) when signing commits with invalid signatures.
Remove the `sign_commit_to_strbuf()` helper from "commit.c" and extend `sign_buffer()` in "gpg-interface.c" to support using the default key as a fallback when the `SIGN_BUFFER_USE_DEFAULT_KEY` flag is provided. Call sites are updated accordingly.
Signed-off-by: Justin Tobler <jltobler@gmail.com> --- builtin/tag.c | 4 ++-- commit.c | 19 +++++-------------- gpg-interface.c | 13 +++++++++++-- gpg-interface.h | 12 ++++++++++-- send-pack.c | 2 +- 5 files changed, 29 insertions(+), 21 deletions(-)
diff --git a/builtin/tag.c b/builtin/tag.c index aeb04c487f..540d783c67 100644 --- a/builtin/tag.c +++ b/builtin/tag.c @@ -167,7 +167,7 @@ static int do_sign(struct strbuf *buffer, struct object_id **compat_oid, char *keyid = get_signing_key(); int ret = -1; - if (sign_buffer(buffer, &sig, keyid)) + if (sign_buffer(buffer, &sig, keyid, 0)) goto out; if (compat) { @@ -176,7 +176,7 @@ static int do_sign(struct strbuf *buffer, struct object_id **compat_oid, if (convert_object_file(the_repository ,&compat_buf, algo, compat, buffer->buf, buffer->len, OBJ_TAG, 1)) goto out; - if (sign_buffer(&compat_buf, &compat_sig, keyid)) + if (sign_buffer(&compat_buf, &compat_sig, keyid, 0)) goto out; add_header_signature(&compat_buf, &sig, algo); strbuf_addbuf(&compat_buf, &compat_sig); diff --git a/commit.c b/commit.c index d16ae73345..1b9b2d4499 100644 --- a/commit.c +++ b/commit.c @@ -1148,18 +1148,6 @@ int add_header_signature(struct strbuf *buf, struct strbuf *sig, const struct gi return 0; } -static int sign_commit_to_strbuf(struct strbuf *sig, struct strbuf *buf, const char *keyid) -{ - char *keyid_to_free = NULL; - int ret = 0; - if (!keyid || !*keyid) - keyid = keyid_to_free = get_signing_key(); - if (sign_buffer(buf, sig, keyid)) - ret = -1; - free(keyid_to_free); - return ret; -} - int parse_signed_commit(const struct commit *commit, struct strbuf *payload, struct strbuf *signature, const struct git_hash_algo *algop) @@ -1737,7 +1725,8 @@ int commit_tree_extended(const char *msg, size_t msg_len, oidcpy(&parent_buf[i++], &p->item->object.oid); write_commit_tree(&buffer, msg, msg_len, tree, parent_buf, nparents, author, committer, extra); - if (sign_commit && sign_commit_to_strbuf(&sig, &buffer, sign_commit)) { + if (sign_commit && sign_buffer(&buffer, &sig, sign_commit, + SIGN_BUFFER_USE_DEFAULT_KEY)) { result = -1; goto out; } @@ -1769,7 +1758,9 @@ int commit_tree_extended(const char *msg, size_t msg_len, free_commit_extra_headers(compat_extra); free(mapped_parents); - if (sign_commit && sign_commit_to_strbuf(&compat_sig, &compat_buffer, sign_commit)) { + if (sign_commit && sign_buffer(&compat_buffer, &compat_sig, + sign_commit, + SIGN_BUFFER_USE_DEFAULT_KEY)) { result = -1; goto out; } diff --git a/gpg-interface.c b/gpg-interface.c index 87fb6605fb..ce935908cc 100644 --- a/gpg-interface.c +++ b/gpg-interface.c @@ -973,11 +973,20 @@ const char *gpg_trust_level_to_str(enum signature_trust_level level) return sigcheck_gpg_trust_level[level].display_key; } -int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key) +int sign_buffer(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key, enum sign_buffer_flags flags) { + char *keyid_to_free = NULL; + int ret = 0; + gpg_interface_lazy_init(); - return use_format->sign_buffer(buffer, signature, signing_key); + if (flags & SIGN_BUFFER_USE_DEFAULT_KEY && (!signing_key || !*signing_key)) + signing_key = keyid_to_free = get_signing_key(); + + ret = use_format->sign_buffer(buffer, signature, signing_key); + free(keyid_to_free); + return ret; } /* diff --git a/gpg-interface.h b/gpg-interface.h index 789d1ffac4..37f3ac42db 100644 --- a/gpg-interface.h +++ b/gpg-interface.h @@ -74,6 +74,15 @@ int parse_signature(const char *buf, size_t size, struct strbuf *payload, struct */ size_t parse_signed_buffer(const char *buf, size_t size); +/* Flags for sign_buffer(). */ +enum sign_buffer_flags { + /* + * Use the default configured signing key as returned by `get_signing_key()` + * when the provided "signing_key" is NULL or empty. + */ + SIGN_BUFFER_USE_DEFAULT_KEY = (1 << 0), +}; + /* * Create a detached signature for the contents of "buffer" and append * it after "signature"; "buffer" and "signature" can be the same @@ -81,8 +90,7 @@ size_t parse_signed_buffer(const char *buf, size_t size); * at the end. Returns 0 on success, non-zero on failure. */ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, - const char *signing_key); - + const char *signing_key, enum sign_buffer_flags flags); /* * Returns corresponding string in lowercase for a given member of diff --git a/send-pack.c b/send-pack.c index 67d6987b1c..07ecfae4de 100644 --- a/send-pack.c +++ b/send-pack.c @@ -391,7 +391,7 @@ static int generate_push_cert(struct strbuf *req_buf, if (!update_seen) goto free_return; - if (sign_buffer(&cert, &cert, signing_key)) + if (sign_buffer(&cert, &cert, signing_key, 0)) die(_("failed to sign the push certificate")); packet_buf_write(req_buf, "push-cert%c%s", 0, cap_string);
-- 2.53.0.381.g628a66ccf6