diff options
authorCarlos Rica <>2007-09-09 00:39:29 (GMT)
committerJunio C Hamano <>2007-09-10 04:30:54 (GMT)
commitaba91192ae39cd1a2f79e7ed91e966df3cfe10b7 (patch)
parent7b02b85a66fee6b357e02f9e70dd0baa0fd24308 (diff)
git-tag -s must fail if gpg cannot sign the tag.
Most of this patch code and message was written by Shawn O. Pearce. I made some tests to know what the problem was, and then I changed the code related with the SIGPIPE signal. If the user has misconfigured `user.signingkey` in their .git/config or just doesn't have any secret keys on their keyring and they ask for a signed tag with `git tag -s` we better make sure the resulting tag was actually signed by gpg. Prior versions of builtin git-tag allowed this failure to slip by without error as they were not checking the return value of the finish_command() so they did not notice when gpg exited with an error exit status. They also did not fail if gpg produced an empty output or if read_in_full received an error from the read system call while trying to read the pipe back from gpg. Finally, we did not actually honor any return value from the do_sign function as it returns ssize_t but was being stored into an unsigned long. This caused the compiler to optimize out the die condition, allowing git-tag to continue along and create the tag object. However, when gpg gets a wrong username, it exits before any read was done and then the writing process receives SIGPIPE and program is terminated. By ignoring this signal, anyway, the function write_or_die gets EPIPE from write_in_full and exits returning 0 to the system without a message. Here we better call to write_in_full directly so we can fail printing a message and return safely to the caller. With these issues fixed `git-tag -s` will now fail to create the tag and will report a non-zero exit status to its caller, thereby allowing automated helper scripts to detect (and recover from) failure if gpg is not working properly. Proposed-by: Shawn O. Pearce <> Signed-off-by: Carlos Rica <> Signed-off-by: Junio C Hamano <>
2 files changed, 21 insertions, 4 deletions
diff --git a/builtin-tag.c b/builtin-tag.c
index 348919c..3a9d2ee 100644
--- a/builtin-tag.c
+++ b/builtin-tag.c
@@ -200,6 +200,10 @@ static ssize_t do_sign(char *buffer, size_t size, size_t max)
bracket[1] = '\0';
+ /* When the username signingkey is bad, program could be terminated
+ * because gpg exits without reading and then write gets SIGPIPE. */
+ signal(SIGPIPE, SIG_IGN);
memset(&gpg, 0, sizeof(gpg));
gpg.argv = args; = -1;
@@ -212,12 +216,17 @@ static ssize_t do_sign(char *buffer, size_t size, size_t max)
if (start_command(&gpg))
return error("could not run gpg.");
- write_or_die(, buffer, size);
+ if (write_in_full(, buffer, size) != size) {
+ close(;
+ finish_command(&gpg);
+ return error("gpg did not accept the tag data");
+ }
gpg.close_in = 0;
len = read_in_full(gpg.out, buffer + size, max - size);
- finish_command(&gpg);
+ if (finish_command(&gpg) || !len || len < 0)
+ return error("gpg failed to sign the tag");
if (len == max - size)
return error("could not read the entire signature from gpg.");
@@ -310,9 +319,10 @@ static void create_tag(const unsigned char *object, const char *tag,
size += header_len;
if (sign) {
- size = do_sign(buffer, size, max_size);
- if (size < 0)
+ ssize_t r = do_sign(buffer, size, max_size);
+ if (r < 0)
die("unable to sign the tag");
+ size = r;
if (write_sha1_file(buffer, size, tag_type, result) < 0)
diff --git a/t/ b/t/
index 606d4f2..0d07bc3 100755
--- a/t/
+++ b/t/
@@ -990,6 +990,13 @@ test_expect_success \
git diff expect actual
+# try to sign with bad user.signingkey
+git config user.signingkey BobTheMouse
+test_expect_failure \
+ 'git-tag -s fails if gpg is misconfigured' \
+ 'git tag -s -m tail tag-gpg-failure'
+git config --unset user.signingkey
# try to verify without gpg:
rm -rf gpghome