gnutls_ext_raw_parse: introduced GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO

This allows parsing extensions from a DTLS client hello.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

6 files changed, 345 insertions, 8 deletions

diff --git a/doc/cha-gtls-app.texi b/doc/cha-gtls-app.texi
index c775f4b2c1..05e1e03a49 100644
--- a/doc/cha-gtls-app.texi
+++ b/doc/cha-gtls-app.texi
@@ -1604,7 +1604,7 @@ handshake_hook_func(gnutls_session_t session, unsigned int htype,
     assert(when == GNUTLS_HOOK_PRE);
 
     ret = gnutls_ext_raw_parse(NULL, ext_hook_func, msg,
-                               GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO);
+                               GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO);
     assert(ret >= 0);
 
     gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cred);
diff --git a/lib/extv.c b/lib/extv.c
index 0abfd370fb..88b723ef39 100644
--- a/lib/extv.c
+++ b/lib/extv.c
@@ -83,13 +83,13 @@ int _gnutls_extv_parse(void *ctx,
  * @ctx: a pointer to pass to callback function
  * @cb: callback function to process each extension found
  * @data: TLS extension data
- * @flags: should be zero or %GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO
+ * @flags: should be zero or %GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO or %GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO
  *
  * This function iterates through the TLS extensions as passed in
  * @data, passing the individual extension data to callback. The
  * @data must conform to Extension extensions<0..2^16-1> format.
  *
- * If flags is %GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO then this function
+ * If flags is %GNUTLS_EXT_RAW_TLS_FLAG_CLIENT_HELLO then this function
  * will parse the extension data from the position, as if the packet in
  * @data is a client hello (without record or handshake headers) -
  * as provided by gnutls_handshake_set_hook_function().
@@ -104,7 +104,7 @@ int _gnutls_extv_parse(void *ctx,
 int gnutls_ext_raw_parse(void *ctx, gnutls_ext_raw_process_func cb,
 			 const gnutls_datum_t *data, unsigned int flags)
 {
-	if (flags & GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO) {
+	if (flags & GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO) {
 		ssize_t size = data->size;
 		size_t len;
 		uint8_t *p = data->data;
@@ -141,6 +141,50 @@ int gnutls_ext_raw_parse(void *ctx, gnutls_ext_raw_process_func cb,
 			return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
 
 		return _gnutls_extv_parse(ctx, cb, p, size);
+	} else if (flags & GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO) {
+		ssize_t size = data->size;
+		size_t len;
+		uint8_t *p = data->data;
+
+		DECR_LEN(size, HANDSHAKE_SESSION_ID_POS);
+
+		if (p[0] != 254)
+			return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_VERSION_PACKET);
+
+		p += HANDSHAKE_SESSION_ID_POS;
+
+		/* skip session id */
+		DECR_LEN(size, 1);
+		len = p[0];
+		p++;
+		DECR_LEN(size, len);
+		p += len;
+
+		/* skip cookie */
+		DECR_LEN(size, 1);
+		len = p[0];
+		p++;
+		DECR_LEN(size, len);
+		p += len;
+
+		/* CipherSuites */
+		DECR_LEN(size, 2);
+		len = _gnutls_read_uint16(p);
+		p += 2;
+		DECR_LEN(size, len);
+		p += len;
+
+		/* legacy_compression_methods */
+		DECR_LEN(size, 1);
+		len = p[0];
+		p++;
+		DECR_LEN(size, len);
+		p += len;
+
+		if (size <= 0)
+			return gnutls_assert_val(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
+
+		return _gnutls_extv_parse(ctx, cb, p, size);
 	}
 
 	if (flags != 0)
diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index 139355b0cb..b6473b98b5 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -2724,7 +2724,8 @@ typedef int (*gnutls_ext_pack_func) (gnutls_ext_priv_data_t data,
 typedef int (*gnutls_ext_unpack_func) (gnutls_buffer_t packed_data,
 				       gnutls_ext_priv_data_t *data);
 
-#define GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO 1
+#define GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO 1
+#define GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO (1<<1)
 typedef int (*gnutls_ext_raw_process_func)(void *ctx, unsigned tls_id, const unsigned char *data, unsigned data_size);
 int gnutls_ext_raw_parse(void *ctx, gnutls_ext_raw_process_func cb,
 			 const gnutls_datum_t *data, unsigned int flags);
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4243c5befe..f29da98724 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -193,7 +193,7 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 x509sign-verify-error rng-op-nonce rng-op-random rng-op-key x509-dn-decode-compat \
 	 ip-check mini-x509-ipaddr trust-store base64-raw random-art dhex509self \
 	 dss-sig-val sign-pk-api tls-session-ext-override mini-record-pad \
-	 tls13-server-kx-neg
+	 tls13-server-kx-neg gnutls_ext_raw_parse_dtls
 
 if HAVE_SECCOMP_TESTS
 ctests += dtls-with-seccomp tls-with-seccomp dtls-client-with-seccomp tls-client-with-seccomp
diff --git a/tests/gnutls_ext_raw_parse.c b/tests/gnutls_ext_raw_parse.c
index 8f1801fb8a..2ffbb77896 100644
--- a/tests/gnutls_ext_raw_parse.c
+++ b/tests/gnutls_ext_raw_parse.c
@@ -51,7 +51,7 @@ int main()
 #include "cert-common.h"
 #include "tls13/ext-parse.h"
 
-/* This program tests gnutls_ext_raw_parse with GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO
+/* This program tests gnutls_ext_raw_parse with GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO
  * flag.
  */
 
@@ -110,7 +110,7 @@ static int handshake_callback(gnutls_session_t session, unsigned int htype,
 
 	if (htype == GNUTLS_HANDSHAKE_CLIENT_HELLO && post) {
 		if (bare_version) {
-			ret = gnutls_ext_raw_parse(NULL, ext_callback, msg, GNUTLS_EXT_RAW_FLAG_CLIENT_HELLO);
+			ret = gnutls_ext_raw_parse(NULL, ext_callback, msg, GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO);
 		} else {
 			unsigned pos;
 			gnutls_datum_t mmsg;
diff --git a/tests/gnutls_ext_raw_parse_dtls.c b/tests/gnutls_ext_raw_parse_dtls.c
new file mode 100644
index 0000000000..6efbb119ba
--- /dev/null
+++ b/tests/gnutls_ext_raw_parse_dtls.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+
+int main()
+{
+	exit(77);
+}
+
+#else
+
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <time.h>
+#include <gnutls/gnutls.h>
+#include <signal.h>
+#include <assert.h>
+
+#include "utils.h"
+#include "cert-common.h"
+#include "tls13/ext-parse.h"
+
+/* This program tests gnutls_ext_raw_parse with GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO
+ * flag.
+ */
+
+#define HOSTNAME "example.com"
+
+static void server_log_func(int level, const char *str)
+{
+	fprintf(stderr, "server|<%d>| %s", level, str);
+}
+
+static void client_log_func(int level, const char *str)
+{
+	fprintf(stderr, "client|<%d>| %s", level, str);
+}
+
+static unsigned found_server_name = 0;
+static unsigned found_status_req = 0;
+
+static int ext_callback(void *ctx, unsigned tls_id, const unsigned char *data, unsigned size)
+{
+	if (tls_id == 0) { /* server name */
+		/* very interesting extension, 4 bytes of sizes
+		 * and 1 byte of type. */
+		unsigned esize = (data[0] << 8) | data[1];
+		assert(esize == strlen(HOSTNAME)+3);
+
+		size -= 2;
+		data += 2;
+
+		assert(data[0] == 0);
+		data++;
+		size--;
+
+		esize = (data[0] << 8) | data[1];
+
+		assert(esize == strlen(HOSTNAME));
+		data += 2;
+		size -= 2;
+
+		assert(memcmp(data, HOSTNAME, strlen(HOSTNAME)) == 0);
+		found_server_name = 1;
+	} else if (tls_id == 5) {
+		found_status_req = 1;
+	} else {
+		if (debug)
+			success("found extension: %u\n", tls_id);
+	}
+	return 0;
+}
+
+static int handshake_callback(gnutls_session_t session, unsigned int htype,
+	unsigned post, unsigned int incoming, const gnutls_datum_t *msg)
+{
+	int ret;
+
+	if (htype == GNUTLS_HANDSHAKE_CLIENT_HELLO && post) {
+		ret = gnutls_ext_raw_parse(NULL, ext_callback, msg, GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO);
+
+		assert(ret >= 0);
+	}
+	return 0;
+}
+
+static void client(int fd)
+{
+	int ret;
+	gnutls_certificate_credentials_t x509_cred;
+	gnutls_session_t session;
+
+	global_init();
+
+	if (debug) {
+		gnutls_global_set_log_function(client_log_func);
+		gnutls_global_set_log_level(7);
+	}
+
+	gnutls_certificate_allocate_credentials(&x509_cred);
+
+	/* Initialize TLS session
+	 */
+	gnutls_init(&session, GNUTLS_CLIENT|GNUTLS_DATAGRAM);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	assert(gnutls_priority_set_direct(session, "NORMAL:-VERS-ALL:+VERS-DTLS1.2", NULL)>= 0);
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+	assert(gnutls_server_name_set(session, GNUTLS_NAME_DNS, HOSTNAME, strlen(HOSTNAME))>=0);
+
+	/* Perform the TLS handshake
+	 */
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+	if (ret == GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM) {
+		/* success */
+		goto end;
+	}
+
+	if (ret < 0) {
+		fail("client: Handshake failed: %s\n", gnutls_strerror(ret));
+	} else {
+		if (debug)
+			success("client: Handshake was completed\n");
+	}
+
+	if (debug)
+		success("client: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+
+      end:
+
+	close(fd);
+
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+}
+
+
+static void server(int fd)
+{
+	int ret;
+	gnutls_session_t session;
+	gnutls_certificate_credentials_t x509_cred;
+
+	/* this must be called once in the program
+	 */
+	global_init();
+
+	if (debug) {
+		gnutls_global_set_log_function(server_log_func);
+		gnutls_global_set_log_level(4711);
+	}
+
+	gnutls_certificate_allocate_credentials(&x509_cred);
+	gnutls_certificate_set_x509_key_mem(x509_cred, &server_cert,
+					    &server_key,
+					    GNUTLS_X509_FMT_PEM);
+
+	gnutls_init(&session, GNUTLS_SERVER|GNUTLS_DATAGRAM);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	gnutls_handshake_set_hook_function(session, GNUTLS_HANDSHAKE_CLIENT_HELLO,
+					   GNUTLS_HOOK_POST,
+					   handshake_callback);
+
+	assert(gnutls_priority_set_direct(session, "NORMAL:-VERS-ALL:+VERS-DTLS1.2", NULL)>= 0);
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+
+	do {
+		ret = gnutls_handshake(session);
+	} while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+	if (ret < 0) {
+		/* failure is expected here */
+		goto end;
+	}
+
+	if (debug)
+		success("server: Handshake was completed\n");
+
+	if (debug)
+		success("server: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	assert(found_server_name != 0);
+	assert(found_status_req != 0);
+
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+
+ end:
+	close(fd);
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+
+	if (debug)
+		success("server: finished\n");
+}
+
+static void ch_handler(int sig)
+{
+	return;
+}
+
+void doit(void)
+{
+	int fd[2];
+	int ret, status = 0;
+	pid_t child;
+
+	signal(SIGCHLD, ch_handler);
+	signal(SIGPIPE, SIG_IGN);
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
+	if (ret < 0) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	child = fork();
+	if (child < 0) {
+		perror("fork");
+		fail("fork");
+		exit(1);
+	}
+
+	if (child) {
+		/* parent */
+		close(fd[1]);
+		server(fd[0]);
+		waitpid(child, &status, 0);
+		check_wait_status(status);
+	} else {
+		close(fd[0]);
+		client(fd[1]);
+		exit(0);
+	}
+
+	return;
+}
+
+
+#endif				/* _WIN32 */