[thirdparty/git.git] / gpg-interface.c

#include "cache.h"
#include "run-command.h"
#include "strbuf.h"
#include "gpg-interface.h"
#include "sigchain.h"

static char *configured_signing_key;
static const char *gpg_program = "gpg";

#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"

void signature_check_clear(struct signature_check *sigc)
{
	free(sigc->payload);
	free(sigc->gpg_output);
	free(sigc->gpg_status);
	free(sigc->signer);
	free(sigc->key);
	sigc->payload = NULL;
	sigc->gpg_output = NULL;
	sigc->gpg_status = NULL;
	sigc->signer = NULL;
	sigc->key = NULL;
}

static struct {
	char result;
	const char *check;
} sigcheck_gpg_status[] = {
	{ 'G', "\n[GNUPG:] GOODSIG " },
	{ 'B', "\n[GNUPG:] BADSIG " },
	{ 'U', "\n[GNUPG:] TRUST_NEVER" },
	{ 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
};

void parse_gpg_output(struct signature_check *sigc)
{
	const char *buf = sigc->gpg_status;
	int i;

	/* Iterate over all search strings */
	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
		const char *found, *next;

		if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
			found = strstr(buf, sigcheck_gpg_status[i].check);
			if (!found)
				continue;
			found += strlen(sigcheck_gpg_status[i].check);
		}
		sigc->result = sigcheck_gpg_status[i].result;
		/* The trust messages are not followed by key/signer information */
		if (sigc->result != 'U') {
			sigc->key = xmemdupz(found, 16);
			found += 17;
			next = strchrnul(found, '\n');
			sigc->signer = xmemdupz(found, next - found);
		}
	}
}

int check_signature(const char *payload, size_t plen, const char *signature,
	size_t slen, struct signature_check *sigc)
{
	struct strbuf gpg_output = STRBUF_INIT;
	struct strbuf gpg_status = STRBUF_INIT;
	int status;

	sigc->result = 'N';

	status = verify_signed_buffer(payload, plen, signature, slen,
				      &gpg_output, &gpg_status);
	if (status && !gpg_output.len)
		goto out;
	sigc->payload = xmemdupz(payload, plen);
	sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
	sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
	parse_gpg_output(sigc);

 out:
	strbuf_release(&gpg_status);
	strbuf_release(&gpg_output);

	return sigc->result != 'G' && sigc->result != 'U';
}

void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
{
	if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
		fputs(sigc->payload, stdout);

	if (sigc->gpg_output)
		fputs(sigc->gpg_output, stderr);
}

/*
 * Look at GPG signed content (e.g. a signed tag object), whose
 * payload is followed by a detached signature on it.  Return the
 * offset where the embedded detached signature begins, or the end of
 * the data when there is no such signature.
 */
size_t parse_signature(const char *buf, unsigned long size)
{
	char *eol;
	size_t len = 0;
	while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
			!starts_with(buf + len, PGP_MESSAGE)) {
		eol = memchr(buf + len, '\n', size - len);
		len += eol ? eol - (buf + len) + 1 : size - len;
	}
	return len;
}

void set_signing_key(const char *key)
{
	free(configured_signing_key);
	configured_signing_key = xstrdup(key);
}

int git_gpg_config(const char *var, const char *value, void *cb)
{
	if (!strcmp(var, "user.signingkey")) {
		set_signing_key(value);
	}
	if (!strcmp(var, "gpg.program")) {
		if (!value)
			return config_error_nonbool(var);
		gpg_program = xstrdup(value);
	}
	return 0;
}

const char *get_signing_key(void)
{
	if (configured_signing_key)
		return configured_signing_key;
	return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
}

/*
 * Create a detached signature for the contents of "buffer" and append
 * it after "signature"; "buffer" and "signature" can be the same
 * strbuf instance, which would cause the detached signature appended
 * at the end.
 */
int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
{
	struct child_process gpg = CHILD_PROCESS_INIT;
	const char *args[4];
	ssize_t len;
	size_t i, j, bottom;

	gpg.argv = args;
	gpg.in = -1;
	gpg.out = -1;
	args[0] = gpg_program;
	args[1] = "-bsau";
	args[2] = signing_key;
	args[3] = NULL;

	if (start_command(&gpg))
		return error(_("could not run gpg."));

	/*
	 * When the username signingkey is bad, program could be terminated
	 * because gpg exits without reading and then write gets SIGPIPE.
	 */
	sigchain_push(SIGPIPE, SIG_IGN);

	if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
		close(gpg.in);
		close(gpg.out);
		finish_command(&gpg);
		return error(_("gpg did not accept the data"));
	}
	close(gpg.in);

	bottom = signature->len;
	len = strbuf_read(signature, gpg.out, 1024);
	close(gpg.out);

	sigchain_pop(SIGPIPE);

	if (finish_command(&gpg) || !len || len < 0)
		return error(_("gpg failed to sign the data"));

	/* Strip CR from the line endings, in case we are on Windows. */
	for (i = j = bottom; i < signature->len; i++)
		if (signature->buf[i] != '\r') {
			if (i != j)
				signature->buf[j] = signature->buf[i];
			j++;
		}
	strbuf_setlen(signature, j);

	return 0;
}

/*
 * Run "gpg" to see if the payload matches the detached signature.
 * gpg_output, when set, receives the diagnostic output from GPG.
 * gpg_status, when set, receives the status output from GPG.
 */
int verify_signed_buffer(const char *payload, size_t payload_size,
			 const char *signature, size_t signature_size,
			 struct strbuf *gpg_output, struct strbuf *gpg_status)
{
	struct child_process gpg = CHILD_PROCESS_INIT;
	const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
	char path[PATH_MAX];
	int fd, ret;
	struct strbuf buf = STRBUF_INIT;
	struct strbuf *pbuf = &buf;

	args_gpg[0] = gpg_program;
	fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
	if (fd < 0)
		return error(_("could not create temporary file '%s': %s"),
			     path, strerror(errno));
	if (write_in_full(fd, signature, signature_size) < 0)
		return error(_("failed writing detached signature to '%s': %s"),
			     path, strerror(errno));
	close(fd);

	gpg.argv = args_gpg;
	gpg.in = -1;
	gpg.out = -1;
	if (gpg_output)
		gpg.err = -1;
	args_gpg[3] = path;
	if (start_command(&gpg)) {
		unlink(path);
		return error(_("could not run gpg."));
	}

	write_in_full(gpg.in, payload, payload_size);
	close(gpg.in);

	if (gpg_output) {
		strbuf_read(gpg_output, gpg.err, 0);
		close(gpg.err);
	}
	if (gpg_status)
		pbuf = gpg_status;
	strbuf_read(pbuf, gpg.out, 0);
	close(gpg.out);

	ret = finish_command(&gpg);

	unlink_or_warn(path);

	ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
	strbuf_release(&buf); /* no matter it was used or not */

	return ret;
}
Commit	Line	Data
2f47eae2 JH	1	#include "cache.h"
	2	#include "run-command.h"
	3	#include "strbuf.h"
	4	#include "gpg-interface.h"
	5	#include "sigchain.h"
	6
	7	static char *configured_signing_key;
0c5e70f0	8	static const char *gpg_program = "gpg";
2f47eae2	9
d7c67668 JH	10	#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
	11	#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
	12
01e57b5d MG	13	void signature_check_clear(struct signature_check *sigc)
01e57b5d MG	14	{
71c214c8	15	free(sigc->payload);
01e57b5d MG	16	free(sigc->gpg_output);
	17	free(sigc->gpg_status);
	18	free(sigc->signer);
	19	free(sigc->key);
71c214c8	20	sigc->payload = NULL;
01e57b5d MG	21	sigc->gpg_output = NULL;
	22	sigc->gpg_status = NULL;
	23	sigc->signer = NULL;
	24	sigc->key = NULL;
	25	}
	26
a50e7ca3 JH	27	static struct {
	28	char result;
	29	const char *check;
	30	} sigcheck_gpg_status[] = {
	31	{ 'G', "\n[GNUPG:] GOODSIG " },
	32	{ 'B', "\n[GNUPG:] BADSIG " },
	33	{ 'U', "\n[GNUPG:] TRUST_NEVER" },
	34	{ 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
	35	};
	36
	37	void parse_gpg_output(struct signature_check *sigc)
	38	{
	39	const char *buf = sigc->gpg_status;
	40	int i;
	41
	42	/* Iterate over all search strings */
	43	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
	44	const char found, next;
	45
	46	if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
	47	found = strstr(buf, sigcheck_gpg_status[i].check);
	48	if (!found)
	49	continue;
	50	found += strlen(sigcheck_gpg_status[i].check);
	51	}
	52	sigc->result = sigcheck_gpg_status[i].result;
	53	/* The trust messages are not followed by key/signer information */
	54	if (sigc->result != 'U') {
	55	sigc->key = xmemdupz(found, 16);
	56	found += 17;
	57	next = strchrnul(found, '\n');
	58	sigc->signer = xmemdupz(found, next - found);
	59	}
	60	}
	61	}
	62
434060ec	63	int check_signature(const char payload, size_t plen, const char signature,
a4cc18f2	64	size_t slen, struct signature_check *sigc)
	65	{
	66	struct strbuf gpg_output = STRBUF_INIT;
	67	struct strbuf gpg_status = STRBUF_INIT;
	68	int status;
	69
	70	sigc->result = 'N';
	71
	72	status = verify_signed_buffer(payload, plen, signature, slen,
	73	&gpg_output, &gpg_status);
	74	if (status && !gpg_output.len)
	75	goto out;
	76	sigc->payload = xmemdupz(payload, plen);
	77	sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
	78	sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
	79	parse_gpg_output(sigc);
	80
	81	out:
	82	strbuf_release(&gpg_status);
	83	strbuf_release(&gpg_output);
434060ec	84
434060ec	85	return sigc->result != 'G' && sigc->result != 'U';
a4cc18f2	86	}
a4cc18f2	87
ca194d50	88	void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
	89	{
	90	if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
	91	fputs(sigc->payload, stdout);
	92
	93	if (sigc->gpg_output)
	94	fputs(sigc->gpg_output, stderr);
	95	}
	96
d7c67668 JH	97	/*
	98	* Look at GPG signed content (e.g. a signed tag object), whose
	99	* payload is followed by a detached signature on it. Return the
	100	* offset where the embedded detached signature begins, or the end of
	101	* the data when there is no such signature.
	102	*/
	103	size_t parse_signature(const char *buf, unsigned long size)
	104	{
	105	char *eol;
	106	size_t len = 0;
	107	while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
	108	!starts_with(buf + len, PGP_MESSAGE)) {
	109	eol = memchr(buf + len, '\n', size - len);
	110	len += eol ? eol - (buf + len) + 1 : size - len;
	111	}
	112	return len;
	113	}
	114
2f47eae2 JH	115	void set_signing_key(const char *key)
	116	{
	117	free(configured_signing_key);
	118	configured_signing_key = xstrdup(key);
	119	}
	120
	121	int git_gpg_config(const char var, const char value, void *cb)
	122	{
	123	if (!strcmp(var, "user.signingkey")) {
0c5e70f0 JH	124	set_signing_key(value);
	125	}
	126	if (!strcmp(var, "gpg.program")) {
2f47eae2 JH	127	if (!value)
2f47eae2 JH	128	return config_error_nonbool(var);
0c5e70f0	129	gpg_program = xstrdup(value);
2f47eae2 JH	130	}
	131	return 0;
	132	}
	133
	134	const char *get_signing_key(void)
	135	{
	136	if (configured_signing_key)
	137	return configured_signing_key;
f9bc573f	138	return git_committer_info(IDENT_STRICT\|IDENT_NO_DATE);
2f47eae2 JH	139	}
	140
	141	/*
	142	* Create a detached signature for the contents of "buffer" and append
	143	* it after "signature"; "buffer" and "signature" can be the same
	144	* strbuf instance, which would cause the detached signature appended
	145	* at the end.
	146	*/
	147	int sign_buffer(struct strbuf buffer, struct strbuf signature, const char *signing_key)
	148	{
d3180279	149	struct child_process gpg = CHILD_PROCESS_INIT;
2f47eae2 JH	150	const char *args[4];
	151	ssize_t len;
	152	size_t i, j, bottom;
	153
2f47eae2 JH	154	gpg.argv = args;
	155	gpg.in = -1;
	156	gpg.out = -1;
0c5e70f0	157	args[0] = gpg_program;
2f47eae2 JH	158	args[1] = "-bsau";
	159	args[2] = signing_key;
	160	args[3] = NULL;
	161
	162	if (start_command(&gpg))
	163	return error(_("could not run gpg."));
	164
	165	/*
	166	* When the username signingkey is bad, program could be terminated
	167	* because gpg exits without reading and then write gets SIGPIPE.
	168	*/
	169	sigchain_push(SIGPIPE, SIG_IGN);
	170
	171	if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
	172	close(gpg.in);
	173	close(gpg.out);
	174	finish_command(&gpg);
	175	return error(_("gpg did not accept the data"));
	176	}
	177	close(gpg.in);
	178
	179	bottom = signature->len;
	180	len = strbuf_read(signature, gpg.out, 1024);
	181	close(gpg.out);
	182
	183	sigchain_pop(SIGPIPE);
	184
	185	if (finish_command(&gpg) \|\| !len \|\| len < 0)
	186	return error(_("gpg failed to sign the data"));
	187
	188	/* Strip CR from the line endings, in case we are on Windows. */
	189	for (i = j = bottom; i < signature->len; i++)
	190	if (signature->buf[i] != '\r') {
	191	if (i != j)
	192	signature->buf[j] = signature->buf[i];
	193	j++;
	194	}
	195	strbuf_setlen(signature, j);
	196
	197	return 0;
	198	}
	199
	200	/*
	201	* Run "gpg" to see if the payload matches the detached signature.
e3f55e07	202	* gpg_output, when set, receives the diagnostic output from GPG.
b60b7566	203	* gpg_status, when set, receives the status output from GPG.
2f47eae2 JH	204	*/
	205	int verify_signed_buffer(const char *payload, size_t payload_size,
	206	const char *signature, size_t signature_size,
9cc4ac8f	207	struct strbuf gpg_output, struct strbuf gpg_status)
2f47eae2	208	{
d3180279	209	struct child_process gpg = CHILD_PROCESS_INIT;
b60b7566	210	const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
2f47eae2 JH	211	char path[PATH_MAX];
2f47eae2 JH	212	int fd, ret;
b60b7566	213	struct strbuf buf = STRBUF_INIT;
9cc4ac8f	214	struct strbuf *pbuf = &buf;
2f47eae2	215
0c5e70f0	216	args_gpg[0] = gpg_program;
2f47eae2 JH	217	fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
2f47eae2 JH	218	if (fd < 0)
4c9a4182	219	return error(_("could not create temporary file '%s': %s"),
2f47eae2 JH	220	path, strerror(errno));
2f47eae2 JH	221	if (write_in_full(fd, signature, signature_size) < 0)
4c9a4182	222	return error(_("failed writing detached signature to '%s': %s"),
2f47eae2 JH	223	path, strerror(errno));
	224	close(fd);
	225
2f47eae2 JH	226	gpg.argv = args_gpg;
2f47eae2 JH	227	gpg.in = -1;
b60b7566	228	gpg.out = -1;
2f47eae2 JH	229	if (gpg_output)
2f47eae2 JH	230	gpg.err = -1;
b60b7566	231	args_gpg[3] = path;
2f47eae2 JH	232	if (start_command(&gpg)) {
2f47eae2 JH	233	unlink(path);
4c9a4182	234	return error(_("could not run gpg."));
2f47eae2 JH	235	}
	236
	237	write_in_full(gpg.in, payload, payload_size);
	238	close(gpg.in);
	239
7dac3f83	240	if (gpg_output) {
2f47eae2	241	strbuf_read(gpg_output, gpg.err, 0);
7dac3f83 SB	242	close(gpg.err);
7dac3f83 SB	243	}
9cc4ac8f MG	244	if (gpg_status)
	245	pbuf = gpg_status;
	246	strbuf_read(pbuf, gpg.out, 0);
b60b7566 MG	247	close(gpg.out);
b60b7566 MG	248
2f47eae2 JH	249	ret = finish_command(&gpg);
	250
	251	unlink_or_warn(path);
	252
9cc4ac8f MG	253	ret \|= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
9cc4ac8f MG	254	strbuf_release(&buf); /* no matter it was used or not */
b60b7566	255
2f47eae2 JH	256	return ret;
2f47eae2 JH	257	}