>From 4183e4ddb6f92a88090e489e2b4f09ea5e9f3a6b Mon Sep 17 00:00:00 2001
From: Carlos Rica <jasampler@xxxxxxxxx>
Date: Sun, 9 Sep 2007 02:39:29 +0200
Subject: [PATCH] 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 <spearce@xxxxxxxxxxx>
Signed-off-by: Carlos Rica <jasampler@xxxxxxxxx>
---
I resend this patch replying to my original message,
but fixing the things commented by Shawn in his
previous response. I also wrote my name as the author of
the patch, to mean that any errors found on these changes
will be only mine, since I spent some time running this to
follow the code involved and see what the real problem was.
Again, comments are welcomed.
This patch
builtin-tag.c | 18 ++++++++++++++----
t/t7004-tag.sh | 7 +++++++
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;
gpg.in = -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(gpg.in, buffer, size);
+ if (write_in_full(gpg.in, buffer, size) != size) {
+ close(gpg.in);
+ finish_command(&gpg);
+ return error("gpg did not accept the tag data");
+ }
close(gpg.in);
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/t7004-tag.sh b/t/t7004-tag.sh
index 606d4f2..0d07bc3 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -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
--
1.5.0
-
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