1 files changed, 345 insertions, 104 deletions

diff --git a/gpg-interface.c b/gpg-interface.c
index d936f3a32f..127aecfc2b 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "commit.h"
 #include "config.h"
 #include "run-command.h"
 #include "strbuf.h"
@@ -7,10 +8,66 @@
 #include "tempfile.h"
 
 static char *configured_signing_key;
-static const char *gpg_program = "gpg";
+static enum signature_trust_level configured_min_trust_level = TRUST_UNDEFINED;
 
-#define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
-#define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
+struct gpg_format {
+	const char *name;
+	const char *program;
+	const char **verify_args;
+	const char **sigs;
+};
+
+static const char *openpgp_verify_args[] = {
+	"--keyid-format=long",
+	NULL
+};
+static const char *openpgp_sigs[] = {
+	"-----BEGIN PGP SIGNATURE-----",
+	"-----BEGIN PGP MESSAGE-----",
+	NULL
+};
+
+static const char *x509_verify_args[] = {
+	NULL
+};
+static const char *x509_sigs[] = {
+	"-----BEGIN SIGNED MESSAGE-----",
+	NULL
+};
+
+static struct gpg_format gpg_format[] = {
+	{ .name = "openpgp", .program = "gpg",
+	  .verify_args = openpgp_verify_args,
+	  .sigs = openpgp_sigs
+	},
+	{ .name = "x509", .program = "gpgsm",
+	  .verify_args = x509_verify_args,
+	  .sigs = x509_sigs
+	},
+};
+
+static struct gpg_format *use_format = &gpg_format[0];
+
+static struct gpg_format *get_format_by_name(const char *str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
+		if (!strcmp(gpg_format[i].name, str))
+			return gpg_format + i;
+	return NULL;
+}
+
+static struct gpg_format *get_format_by_sig(const char *sig)
+{
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(gpg_format); i++)
+		for (j = 0; gpg_format[i].sigs[j]; j++)
+			if (starts_with(sig, gpg_format[i].sigs[j]))
+				return gpg_format + i;
+	return NULL;
+}
 
 void signature_check_clear(struct signature_check *sigc)
 {
@@ -19,49 +76,234 @@ void signature_check_clear(struct signature_check *sigc)
 	FREE_AND_NULL(sigc->gpg_status);
 	FREE_AND_NULL(sigc->signer);
 	FREE_AND_NULL(sigc->key);
+	FREE_AND_NULL(sigc->fingerprint);
+	FREE_AND_NULL(sigc->primary_key_fingerprint);
 }
 
+/* An exclusive status -- only one of them can appear in output */
+#define GPG_STATUS_EXCLUSIVE	(1<<0)
+/* The status includes key identifier */
+#define GPG_STATUS_KEYID	(1<<1)
+/* The status includes user identifier */
+#define GPG_STATUS_UID		(1<<2)
+/* The status includes key fingerprints */
+#define GPG_STATUS_FINGERPRINT	(1<<3)
+/* The status includes trust level */
+#define GPG_STATUS_TRUST_LEVEL	(1<<4)
+
+/* Short-hand for standard exclusive *SIG status with keyid & UID */
+#define GPG_STATUS_STDSIG	(GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID|GPG_STATUS_UID)
+
 static struct {
 	char result;
 	const char *check;
+	unsigned int flags;
 } sigcheck_gpg_status[] = {
-	{ 'G', "\n[GNUPG:] GOODSIG " },
-	{ 'B', "\n[GNUPG:] BADSIG " },
-	{ 'U', "\n[GNUPG:] TRUST_NEVER" },
-	{ 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
-	{ 'E', "\n[GNUPG:] ERRSIG "},
-	{ 'X', "\n[GNUPG:] EXPSIG "},
-	{ 'Y', "\n[GNUPG:] EXPKEYSIG "},
-	{ 'R', "\n[GNUPG:] REVKEYSIG "},
+	{ 'G', "GOODSIG ", GPG_STATUS_STDSIG },
+	{ 'B', "BADSIG ", GPG_STATUS_STDSIG },
+	{ 'E', "ERRSIG ", GPG_STATUS_EXCLUSIVE|GPG_STATUS_KEYID },
+	{ 'X', "EXPSIG ", GPG_STATUS_STDSIG },
+	{ 'Y', "EXPKEYSIG ", GPG_STATUS_STDSIG },
+	{ 'R', "REVKEYSIG ", GPG_STATUS_STDSIG },
+	{ 0, "VALIDSIG ", GPG_STATUS_FINGERPRINT },
+	{ 0, "TRUST_", GPG_STATUS_TRUST_LEVEL },
+};
+
+static struct {
+	const char *key;
+	enum signature_trust_level value;
+} sigcheck_gpg_trust_level[] = {
+	{ "UNDEFINED", TRUST_UNDEFINED },
+	{ "NEVER", TRUST_NEVER },
+	{ "MARGINAL", TRUST_MARGINAL },
+	{ "FULLY", TRUST_FULLY },
+	{ "ULTIMATE", TRUST_ULTIMATE },
 };
 
-void parse_gpg_output(struct signature_check *sigc)
+static void replace_cstring(char **field, const char *line, const char *next)
 {
-	const char *buf = sigc->gpg_status;
-	int i;
+	free(*field);
 
-	/* Iterate over all search strings */
-	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
-		const char *found, *next;
+	if (line && next)
+		*field = xmemdupz(line, next - line);
+	else
+		*field = NULL;
+}
+
+static int parse_gpg_trust_level(const char *level,
+				 enum signature_trust_level *res)
+{
+	size_t i;
 
-		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);
+	for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_trust_level); i++) {
+		if (!strcmp(sigcheck_gpg_trust_level[i].key, level)) {
+			*res = sigcheck_gpg_trust_level[i].value;
+			return 0;
 		}
-		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);
-			/* The ERRSIG message is not followed by signer information */
-			if (sigc-> result != 'E') {
-				found += 17;
-				next = strchrnul(found, '\n');
-				sigc->signer = xmemdupz(found, next - found);
+	}
+	return 1;
+}
+
+static void parse_gpg_output(struct signature_check *sigc)
+{
+	const char *buf = sigc->gpg_status;
+	const char *line, *next;
+	int i, j;
+	int seen_exclusive_status = 0;
+
+	/* Iterate over all lines */
+	for (line = buf; *line; line = strchrnul(line+1, '\n')) {
+		while (*line == '\n')
+			line++;
+		if (!*line)
+			break;
+
+		/* Skip lines that don't start with GNUPG status */
+		if (!skip_prefix(line, "[GNUPG:] ", &line))
+			continue;
+
+		/* Iterate over all search strings */
+		for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
+			if (skip_prefix(line, sigcheck_gpg_status[i].check, &line)) {
+				/*
+				 * GOODSIG, BADSIG etc. can occur only once for
+				 * each signature.  Therefore, if we had more
+				 * than one then we're dealing with multiple
+				 * signatures.  We don't support them
+				 * currently, and they're rather hard to
+				 * create, so something is likely fishy and we
+				 * should reject them altogether.
+				 */
+				if (sigcheck_gpg_status[i].flags & GPG_STATUS_EXCLUSIVE) {
+					if (seen_exclusive_status++)
+						goto error;
+				}
+
+				if (sigcheck_gpg_status[i].result)
+					sigc->result = sigcheck_gpg_status[i].result;
+				/* Do we have key information? */
+				if (sigcheck_gpg_status[i].flags & GPG_STATUS_KEYID) {
+					next = strchrnul(line, ' ');
+					replace_cstring(&sigc->key, line, next);
+					/* Do we have signer information? */
+					if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) {
+						line = next + 1;
+						next = strchrnul(line, '\n');
+						replace_cstring(&sigc->signer, line, next);
+					}
+				}
+
+				/* Do we have trust level? */
+				if (sigcheck_gpg_status[i].flags & GPG_STATUS_TRUST_LEVEL) {
+					/*
+					 * GPG v1 and v2 differs in how the
+					 * TRUST_ lines are written.  Some
+					 * trust lines contain no additional
+					 * space-separated information for v1.
+					 */
+					size_t trust_size = strcspn(line, " \n");
+					char *trust = xmemdupz(line, trust_size);
+
+					if (parse_gpg_trust_level(trust, &sigc->trust_level)) {
+						free(trust);
+						goto error;
+					}
+					free(trust);
+				}
+
+				/* Do we have fingerprint? */
+				if (sigcheck_gpg_status[i].flags & GPG_STATUS_FINGERPRINT) {
+					const char *limit;
+					char **field;
+
+					next = strchrnul(line, ' ');
+					replace_cstring(&sigc->fingerprint, line, next);
+
+					/*
+					 * Skip interim fields.  The search is
+					 * limited to the same line since only
+					 * OpenPGP signatures has a field with
+					 * the primary fingerprint.
+					 */
+					limit = strchrnul(line, '\n');
+					for (j = 9; j > 0; j--) {
+						if (!*next || limit <= next)
+							break;
+						line = next + 1;
+						next = strchrnul(line, ' ');
+					}
+
+					field = &sigc->primary_key_fingerprint;
+					if (!j) {
+						next = strchrnul(line, '\n');
+						replace_cstring(field, line, next);
+					} else {
+						replace_cstring(field, NULL, NULL);
+					}
+				}
+
+				break;
 			}
 		}
 	}
+	return;
+
+error:
+	sigc->result = 'E';
+	/* Clear partial data to avoid confusion */
+	FREE_AND_NULL(sigc->primary_key_fingerprint);
+	FREE_AND_NULL(sigc->fingerprint);
+	FREE_AND_NULL(sigc->signer);
+	FREE_AND_NULL(sigc->key);
+}
+
+static 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;
+	struct gpg_format *fmt;
+	struct tempfile *temp;
+	int ret;
+	struct strbuf buf = STRBUF_INIT;
+
+	temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
+	if (!temp)
+		return error_errno(_("could not create temporary file"));
+	if (write_in_full(temp->fd, signature, signature_size) < 0 ||
+	    close_tempfile_gently(temp) < 0) {
+		error_errno(_("failed writing detached signature to '%s'"),
+			    temp->filename.buf);
+		delete_tempfile(&temp);
+		return -1;
+	}
+
+	fmt = get_format_by_sig(signature);
+	if (!fmt)
+		BUG("bad signature '%s'", signature);
+
+	strvec_push(&gpg.args, fmt->program);
+	strvec_pushv(&gpg.args, fmt->verify_args);
+	strvec_pushl(&gpg.args,
+		     "--status-fd=1",
+		     "--verify", temp->filename.buf, "-",
+		     NULL);
+
+	if (!gpg_status)
+		gpg_status = &buf;
+
+	sigchain_push(SIGPIPE, SIG_IGN);
+	ret = pipe_command(&gpg, payload, payload_size,
+			   gpg_status, 0, gpg_output, 0);
+	sigchain_pop(SIGPIPE);
+
+	delete_tempfile(&temp);
+
+	ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
+	strbuf_release(&buf); /* no matter it was used or not */
+
+	return ret;
 }
 
 int check_signature(const char *payload, size_t plen, const char *signature,
@@ -72,6 +314,7 @@ int check_signature(const char *payload, size_t plen, const char *signature,
 	int status;
 
 	sigc->result = 'N';
+	sigc->trust_level = -1;
 
 	status = verify_signed_buffer(payload, plen, signature, slen,
 				      &gpg_output, &gpg_status);
@@ -81,12 +324,14 @@ int check_signature(const char *payload, size_t plen, const char *signature,
 	sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
 	sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
 	parse_gpg_output(sigc);
+	status |= sigc->result != 'G';
+	status |= sigc->trust_level < configured_min_trust_level;
 
  out:
 	strbuf_release(&gpg_status);
 	strbuf_release(&gpg_output);
 
-	return sigc->result != 'G' && sigc->result != 'U';
+	return !!status;
 }
 
 void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
@@ -101,22 +346,32 @@ void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 		fputs(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)
+size_t parse_signed_buffer(const char *buf, size_t size)
 {
-	char *eol;
 	size_t len = 0;
-	while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
-			!starts_with(buf + len, PGP_MESSAGE)) {
+	size_t match = size;
+	while (len < size) {
+		const char *eol;
+
+		if (get_format_by_sig(buf + len))
+			match = len;
+
 		eol = memchr(buf + len, '\n', size - len);
 		len += eol ? eol - (buf + len) + 1 : size - len;
 	}
-	return len;
+	return match;
+}
+
+int parse_signature(const char *buf, size_t size, struct strbuf *payload, struct strbuf *signature)
+{
+	size_t match = parse_signed_buffer(buf, size);
+	if (match != size) {
+		strbuf_add(payload, buf, match);
+		remove_signature(payload);
+		strbuf_add(signature, buf + match, size - match);
+		return 1;
+	}
+	return 0;
 }
 
 void set_signing_key(const char *key)
@@ -127,14 +382,54 @@ void set_signing_key(const char *key)
 
 int git_gpg_config(const char *var, const char *value, void *cb)
 {
+	struct gpg_format *fmt = NULL;
+	char *fmtname = NULL;
+	char *trust;
+	int ret;
+
 	if (!strcmp(var, "user.signingkey")) {
+		if (!value)
+			return config_error_nonbool(var);
 		set_signing_key(value);
+		return 0;
+	}
+
+	if (!strcmp(var, "gpg.format")) {
+		if (!value)
+			return config_error_nonbool(var);
+		fmt = get_format_by_name(value);
+		if (!fmt)
+			return error("unsupported value for %s: %s",
+				     var, value);
+		use_format = fmt;
+		return 0;
 	}
-	if (!strcmp(var, "gpg.program")) {
+
+	if (!strcmp(var, "gpg.mintrustlevel")) {
 		if (!value)
 			return config_error_nonbool(var);
-		gpg_program = xstrdup(value);
+
+		trust = xstrdup_toupper(value);
+		ret = parse_gpg_trust_level(trust, &configured_min_trust_level);
+		free(trust);
+
+		if (ret)
+			return error("unsupported value for %s: %s", var,
+				     value);
+		return 0;
+	}
+
+	if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
+		fmtname = "openpgp";
+
+	if (!strcmp(var, "gpg.x509.program"))
+		fmtname = "x509";
+
+	if (fmtname) {
+		fmt = get_format_by_name(fmtname);
+		return git_config_string(&fmt->program, var, value);
 	}
+
 	return 0;
 }
 
@@ -145,12 +440,6 @@ const char *get_signing_key(void)
 	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;
@@ -158,11 +447,11 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 	size_t i, j, bottom;
 	struct strbuf gpg_status = STRBUF_INIT;
 
-	argv_array_pushl(&gpg.args,
-			 gpg_program,
-			 "--status-fd=2",
-			 "-bsau", signing_key,
-			 NULL);
+	strvec_pushl(&gpg.args,
+		     use_format->program,
+		     "--status-fd=2",
+		     "-bsau", signing_key,
+		     NULL);
 
 	bottom = signature->len;
 
@@ -191,51 +480,3 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 
 	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;
-	static struct tempfile temp;
-	int fd, ret;
-	struct strbuf buf = STRBUF_INIT;
-
-	fd = mks_tempfile_t(&temp, ".git_vtag_tmpXXXXXX");
-	if (fd < 0)
-		return error_errno(_("could not create temporary file"));
-	if (write_in_full(fd, signature, signature_size) < 0) {
-		error_errno(_("failed writing detached signature to '%s'"),
-			    temp.filename.buf);
-		delete_tempfile(&temp);
-		return -1;
-	}
-	close(fd);
-
-	argv_array_pushl(&gpg.args,
-			 gpg_program,
-			 "--status-fd=1",
-			 "--keyid-format=long",
-			 "--verify", temp.filename.buf, "-",
-			 NULL);
-
-	if (!gpg_status)
-		gpg_status = &buf;
-
-	sigchain_push(SIGPIPE, SIG_IGN);
-	ret = pipe_command(&gpg, payload, payload_size,
-			   gpg_status, 0, gpg_output, 0);
-	sigchain_pop(SIGPIPE);
-
-	delete_tempfile(&temp);
-
-	ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
-	strbuf_release(&buf); /* no matter it was used or not */
-
-	return ret;
-}