From aba91192ae39cd1a2f79e7ed91e966df3cfe10b7 Mon Sep 17 00:00:00 2001 From: Carlos Rica Date: Sun, 9 Sep 2007 02:39:29 +0200 Subject: 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 --- 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 348919cff8..3a9d2eea71 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 606d4f2a2c..0d07bc39c7 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 -- cgit v1.2.3