serv, cli: add --keymatexport option

This adds --keymatexport and --keymatexportsize options to both
gnutls-serv and gnutls-cli.  Those would be useful for testing
interoperability with other implementations.

Signed-off-by: Daiki Ueno <dueno@redhat.com>

6 files changed, 78 insertions, 0 deletions

diff --git a/src/cli-args.def b/src/cli-args.def
index 518a97466e..621de61f3c 100644
--- a/src/cli-args.def
+++ b/src/cli-args.def
@@ -423,6 +423,20 @@ flag = {
     doc       = "";
 };
 
+flag = {
+    name      = keymatexport;
+    arg-type  = string;
+    descrip   = "Label used for exporting keying material";
+    doc      = "";
+};
+
+flag = {
+    name      = keymatexportsize;
+    arg-type  = number;
+    descrip   = "Size of the exported keying material";
+    doc      = "";
+};
+
 doc-section = {
   ds-type   = 'SEE ALSO'; // or anything else
   ds-format = 'texi';      // or texi or mdoc format
diff --git a/src/cli.c b/src/cli.c
index a770c74bcc..691eb98c54 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -1659,6 +1659,11 @@ int do_handshake(socket_st * socket)
 	if (ret == 0) {
 		/* print some information */
 		print_info(socket->session, verbose, HAVE_OPT(X509CERTFILE)?P_WAIT_FOR_CERT:0);
+		if (HAVE_OPT(KEYMATEXPORT))
+			print_key_material(socket->session,
+					   OPT_ARG(KEYMATEXPORT),
+					   HAVE_OPT(KEYMATEXPORTSIZE) ?
+					   OPT_VALUE_KEYMATEXPORTSIZE : 20);
 		socket->secure = 1;
 	} else {
 		gnutls_alert_send_appropriate(socket->session, ret);
diff --git a/src/common.c b/src/common.c
index 28452fd589..664513c9ad 100644
--- a/src/common.c
+++ b/src/common.c
@@ -876,6 +876,43 @@ void print_list(const char *priorities, int verbose)
 	}
 }
 
+void
+print_key_material(gnutls_session_t session, const char *label, size_t size)
+{
+	gnutls_datum_t bin = { NULL, 0 }, hex = { NULL, 0 };
+	int ret;
+
+	bin.data = gnutls_malloc(size);
+	if (!bin.data) {
+		fprintf(stderr, "Error in gnutls_malloc: %s\n",
+			gnutls_strerror(GNUTLS_E_MEMORY_ERROR));
+		goto out;
+	}
+
+	bin.size = size;
+
+	ret = gnutls_prf_rfc5705(session, strlen(label), label,
+				 0, NULL, size, (char *)bin.data);
+	if (ret < 0) {
+		fprintf(stderr, "Error in gnutls_prf_rfc5705: %s\n",
+			gnutls_strerror(ret));
+		goto out;
+	}
+
+	ret = gnutls_hex_encode2(&bin, &hex);
+	if (ret < 0) {
+		fprintf(stderr, "Error in hex encoding: %s\n",
+			gnutls_strerror(ret));
+		goto out;
+	}
+	log_msg(stdout, "- Key material: %s\n", hex.data);
+	fflush(stdout);
+
+ out:
+	gnutls_free(bin.data);
+	gnutls_free(hex.data);
+}
+
 int check_command(gnutls_session_t session, const char *str, unsigned no_cli_cert)
 {
 	size_t len = strnlen(str, 128);
diff --git a/src/common.h b/src/common.h
index 588ee82bf1..91b9ed04f2 100644
--- a/src/common.h
+++ b/src/common.h
@@ -61,6 +61,7 @@ extern const char str_unknown[];
 #define P_WAIT_FOR_CERT (1<<1)
 int print_info(gnutls_session_t state, int verbose, int flags);
 void print_cert_info(gnutls_session_t, int flag, int print_cert);
+void print_key_material(gnutls_session_t, const char *label, size_t size);
 
 int log_msg(FILE *file, const char *message, ...) __attribute__((format(printf, 2, 3)));
 void log_set(FILE *file);
diff --git a/src/serv-args.def b/src/serv-args.def
index ac056f37dc..4be3d9f298 100644
--- a/src/serv-args.def
+++ b/src/serv-args.def
@@ -318,6 +318,20 @@ flag = {
     doc      = "This will override the default options in /etc/gnutls/pkcs11.conf";
 };
 
+flag = {
+    name      = keymatexport;
+    arg-type  = string;
+    descrip   = "Label used for exporting keying material";
+    doc      = "";
+};
+
+flag = {
+    name      = keymatexportsize;
+    arg-type  = number;
+    descrip   = "Size of the exported keying material";
+    doc      = "";
+};
+
 doc-section = {
   ds-type   = 'SEE ALSO'; // or anything else
   ds-format = 'texi';      // or texi or mdoc format
diff --git a/src/serv.c b/src/serv.c
index bc490ee7da..0866bff903 100644
--- a/src/serv.c
+++ b/src/serv.c
@@ -1331,6 +1331,13 @@ static void retry_handshake(listener_item *j)
 #endif
 
 			print_info(j->tls_session, verbose, verbose);
+
+			if (HAVE_OPT(KEYMATEXPORT))
+				print_key_material(j->tls_session,
+						   OPT_ARG(KEYMATEXPORT),
+						   HAVE_OPT(KEYMATEXPORTSIZE) ?
+						   OPT_VALUE_KEYMATEXPORTSIZE :
+						   20);
 		}
 
 		j->close_ok = 1;