gpg-interface: allow sign_buffer() to use default signing key

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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/tag.c b/builtin/tag.c
index aeb04c487fe95a671932937a83d577b0e76ac4a4..540d783c67ded24b0a6e4af197f7a85a17302b46 100644 (file)
--- 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 0ffdd6679eec804e9d51db4ba5a6f298d1223b75..80d8d078757dbc4fd534bc038f4774850e57bf6c 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -1170,18 +1170,6 @@ 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)
@@ -1759,7 +1747,8 @@ 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;
        }
@@ -1791,7 +1780,9 @@ 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 7e6a1520bd1535409fcdacb88465fc638865f516..27eacbb632628c09b3d37f0b1c6807ad997c0bb9 100644 (file)
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -974,11 +974,20 @@ 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 789d1ffac4785064657d6c2465078f9b23d8b9af..37f3ac42dbb99a3c5c3c85c697a834b0f2ca0d52 100644 (file)
--- 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 67d6987b1ccd7ed8a758c407e1e01bf7e53d6bd0..07ecfae4de92a29b5d6e303e2efaba8ed0a5fb35 100644 (file)
--- 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);