Commit d07b00b7 authored by Michael J Gruber's avatar Michael J Gruber Committed by Junio C Hamano

verify-commit: scriptable commit signature verification

Commit signatures can be verified using "git show -s --show-signature"
or the "%G?" pretty format and parsing the output, which is well suited
for user inspection, but not for scripting.

Provide a command "verify-commit" which is analogous to "verify-tag": It
returns 0 for good signatures and non-zero otherwise, has the gpg output
on stderr and (optionally) the commit object on stdout, sans the
signature, just like "verify-tag" does.
Signed-off-by: default avatarMichael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
parent 71c214c8
git-verify-commit(1)
====================
NAME
----
git-verify-commit - Check the GPG signature of commits
SYNOPSIS
--------
[verse]
'git verify-commit' <commit>...
DESCRIPTION
-----------
Validates the gpg signature created by 'git commit -S'.
OPTIONS
-------
-v::
--verbose::
Print the contents of the commit object before validating it.
<commit>...::
SHA-1 identifiers of Git commit objects.
GIT
---
Part of the linkgit:git[1] suite
......@@ -999,6 +999,7 @@ BUILTIN_OBJS += builtin/update-ref.o
BUILTIN_OBJS += builtin/update-server-info.o
BUILTIN_OBJS += builtin/upload-archive.o
BUILTIN_OBJS += builtin/var.o
BUILTIN_OBJS += builtin/verify-commit.o
BUILTIN_OBJS += builtin/verify-pack.o
BUILTIN_OBJS += builtin/verify-tag.o
BUILTIN_OBJS += builtin/write-tree.o
......
......@@ -128,6 +128,7 @@ extern int cmd_update_server_info(int argc, const char **argv, const char *prefi
extern int cmd_upload_archive(int argc, const char **argv, const char *prefix);
extern int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix);
extern int cmd_var(int argc, const char **argv, const char *prefix);
extern int cmd_verify_commit(int argc, const char **argv, const char *prefix);
extern int cmd_verify_tag(int argc, const char **argv, const char *prefix);
extern int cmd_version(int argc, const char **argv, const char *prefix);
extern int cmd_whatchanged(int argc, const char **argv, const char *prefix);
......
/*
* Builtin "git commit-commit"
*
* Copyright (c) 2014 Michael J Gruber <git@drmicha.warpmail.net>
*
* Based on git-verify-tag
*/
#include "cache.h"
#include "builtin.h"
#include "commit.h"
#include "run-command.h"
#include <signal.h>
#include "parse-options.h"
#include "gpg-interface.h"
static const char * const verify_commit_usage[] = {
N_("git verify-commit [-v|--verbose] <commit>..."),
NULL
};
static int run_gpg_verify(const unsigned char *sha1, const char *buf, unsigned long size, int verbose)
{
struct signature_check signature_check;
memset(&signature_check, 0, sizeof(signature_check));
check_commit_signature(lookup_commit(sha1), &signature_check);
if (verbose && signature_check.payload)
fputs(signature_check.payload, stdout);
if (signature_check.gpg_output)
fputs(signature_check.gpg_output, stderr);
signature_check_clear(&signature_check);
return signature_check.result != 'G';
}
static int verify_commit(const char *name, int verbose)
{
enum object_type type;
unsigned char sha1[20];
char *buf;
unsigned long size;
int ret;
if (get_sha1(name, sha1))
return error("commit '%s' not found.", name);
buf = read_sha1_file(sha1, &type, &size);
if (!buf)
return error("%s: unable to read file.", name);
if (type != OBJ_COMMIT)
return error("%s: cannot verify a non-commit object of type %s.",
name, typename(type));
ret = run_gpg_verify(sha1, buf, size, verbose);
free(buf);
return ret;
}
static int git_verify_commit_config(const char *var, const char *value, void *cb)
{
int status = git_gpg_config(var, value, cb);
if (status)
return status;
return git_default_config(var, value, cb);
}
int cmd_verify_commit(int argc, const char **argv, const char *prefix)
{
int i = 1, verbose = 0, had_error = 0;
const struct option verify_commit_options[] = {
OPT__VERBOSE(&verbose, N_("print commit contents")),
OPT_END()
};
git_config(git_verify_commit_config, NULL);
argc = parse_options(argc, argv, prefix, verify_commit_options,
verify_commit_usage, PARSE_OPT_KEEP_ARGV0);
if (argc <= i)
usage_with_options(verify_commit_usage, verify_commit_options);
/* sometimes the program was terminated because this signal
* was received in the process of writing the gpg input: */
signal(SIGPIPE, SIG_IGN);
while (i < argc)
if (verify_commit(argv[i++], verbose))
had_error = 1;
return had_error;
}
......@@ -132,6 +132,7 @@ git-update-server-info synchingrepositories
git-upload-archive synchelpers
git-upload-pack synchelpers
git-var plumbinginterrogators
git-verify-commit ancillaryinterrogators
git-verify-pack plumbinginterrogators
git-verify-tag ancillaryinterrogators
gitweb ancillaryinterrogators
......
......@@ -441,6 +441,7 @@ static struct cmd_struct commands[] = {
{ "upload-archive", cmd_upload_archive },
{ "upload-archive--writer", cmd_upload_archive_writer },
{ "var", cmd_var, RUN_SETUP_GENTLY },
{ "verify-commit", cmd_verify_commit, RUN_SETUP },
{ "verify-pack", cmd_verify_pack },
{ "verify-tag", cmd_verify_tag, RUN_SETUP },
{ "version", cmd_version },
......
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