ext/record_size_limit: new extensiontmp-record-size-limit

This implements the record_size_limit extension as defined in RFC 8449.

Although it obsoletes the max_record_size extension, for compatibility
reasons GnuTLS still sends it on certain occasions.  For example, when
the new size is representable as the codepoint defined for
max_record_size.

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

11 files changed, 615 insertions, 31 deletions

diff --git a/NEWS b/NEWS
index e6e4ffb6bb..7b9a53d00a 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,9 @@ See the end for copying conditions.
    certificate is presented by client and the gnutls_init() flag GNUTLS_ENABLE_EARLY_START
    is specified.
 
+** libgnutls: The 'record size limit' extension is added and preferred to the
+   'max record size' extension when possible.
+
 ** API and ABI modifications:
 GNUTLS_ENABLE_EARLY_START: Added
 gnutls_record_set_max_early_data_size: Added
diff --git a/lib/ext/Makefile.am b/lib/ext/Makefile.am
index cbd68c8588..b7f204f1d9 100644
--- a/lib/ext/Makefile.am
+++ b/lib/ext/Makefile.am
@@ -47,7 +47,8 @@ libgnutls_ext_la_SOURCES = max_record.c \
 	psk_ke_modes.c psk_ke_modes.h pre_shared_key.c pre_shared_key.h \
 	supported_groups.c supported_groups.h \
 	ec_point_formats.c ec_point_formats.h \
-	early_data.c early_data.h
+	early_data.c early_data.h \
+	record_size_limit.c record_size_limit.h
 
 if ENABLE_ALPN
 libgnutls_ext_la_SOURCES += alpn.c alpn.h
diff --git a/lib/ext/max_record.c b/lib/ext/max_record.c
index 8edf5a2183..2a7a9d3496 100644
--- a/lib/ext/max_record.c
+++ b/lib/ext/max_record.c
@@ -70,6 +70,9 @@ _gnutls_max_record_recv_params(gnutls_session_t session,
 	ssize_t new_size;
 	ssize_t data_size = _data_size;
 
+	if (session->internals.hsk_flags & HSK_RECORD_SIZE_LIMIT_NEGOTIATED)
+		return 0;
+
 	if (session->security_parameters.entity == GNUTLS_SERVER) {
 		if (data_size > 0) {
 			DECR_LEN(data_size, 1);
@@ -96,8 +99,12 @@ _gnutls_max_record_recv_params(gnutls_session_t session,
 
 			new_size = _gnutls_mre_num2record(data[0]);
 
-			if (new_size < 0 ||
-			    new_size != session->security_parameters.
+			if (new_size < 0) {
+				gnutls_assert();
+				return new_size;
+			}
+
+			if (new_size != session->security_parameters.
 			    max_record_send_size) {
 				gnutls_assert();
 				return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
@@ -127,11 +134,16 @@ _gnutls_max_record_send_params(gnutls_session_t session,
 	if (session->security_parameters.entity == GNUTLS_CLIENT) {
 		if (session->security_parameters.max_record_send_size !=
 		    DEFAULT_MAX_RECORD_SIZE) {
-			p = (uint8_t)
-			    _gnutls_mre_record2num
-			    (session->security_parameters.
-			     max_record_send_size);
+			ret = _gnutls_mre_record2num
+			      (session->security_parameters.
+			       max_record_send_size);
+
+			/* it's not an error, as long as we send the
+			 * record_size_limit extension with that value */
+			if (ret < 0)
+				return 0;
 
+			p = (uint8_t) ret;
 			ret = _gnutls_buffer_append_data(extdata, &p, 1);
 			if (ret < 0)
 				return gnutls_assert_val(ret);
@@ -143,11 +155,16 @@ _gnutls_max_record_send_params(gnutls_session_t session,
 
 		if (session->security_parameters.max_record_recv_size !=
 		    DEFAULT_MAX_RECORD_SIZE) {
-			p = (uint8_t)
-			    _gnutls_mre_record2num
-			    (session->security_parameters.
-			     max_record_recv_size);
+			ret = _gnutls_mre_record2num
+			      (session->security_parameters.
+			       max_record_recv_size);
 
+			/* it's not an error, as long as we send the
+			 * record_size_limit extension with that value */
+			if (ret < 0)
+				return 0;
+
+			p = (uint8_t) ret;
 			ret = _gnutls_buffer_append_data(extdata, &p, 1);
 			if (ret < 0)
 				return gnutls_assert_val(ret);
@@ -226,30 +243,28 @@ size_t gnutls_record_get_max_size(gnutls_session_t session)
  * connection.  This property can only be set to clients.  The server
  * may choose not to accept the requested size.
  *
- * Acceptable values are 512(=2^9), 1024(=2^10), 2048(=2^11) and
- * 4096(=2^12).  The requested record size does get in effect
- * immediately only while sending data. The receive part will take
- * effect after a successful handshake.
+ * The requested record size does get in effect immediately only while
+ * sending data. The receive part will take effect after a successful
+ * handshake.
  *
- * This function uses a TLS extension called 'max record size'.  Not
- * all TLS implementations use or even understand this extension.
+ * Prior to 3.6.4, this function was implemented using a TLS extension
+ * called 'max record size', which limits the acceptable values to
+ * 512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12). Since 3.6.4,
+ * it uses another TLS extension called 'record size limit', which
+ * doesn't have the limitation, as long as the value ranges between
+ * 512 and 16384.  Note that not all TLS implementations use or even
+ * understand those extension.
  *
  * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
  *   otherwise a negative error code is returned.
  **/
 ssize_t gnutls_record_set_max_size(gnutls_session_t session, size_t size)
 {
-	ssize_t new_size;
-
 	if (session->security_parameters.entity == GNUTLS_SERVER)
 		return GNUTLS_E_INVALID_REQUEST;
 
-	new_size = _gnutls_mre_record2num(size);
-
-	if (new_size < 0) {
-		gnutls_assert();
-		return new_size;
-	}
+	if (size < MIN_RECORD_SIZE || size > DEFAULT_MAX_RECORD_SIZE)
+		return GNUTLS_E_INVALID_REQUEST;
 
 	session->security_parameters.max_record_send_size = size;
 
diff --git a/lib/ext/record_size_limit.c b/lib/ext/record_size_limit.c
new file mode 100644
index 0000000000..0bc4c63792
--- /dev/null
+++ b/lib/ext/record_size_limit.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Daiki Ueno
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser 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/>
+ *
+ */
+
+/* This file contains the code for the Record Size Limit TLS extension.
+ */
+
+#include "gnutls_int.h"
+#include "errors.h"
+#include "num.h"
+#include <hello_ext.h>
+#include <ext/record_size_limit.h>
+
+static int _gnutls_record_size_limit_recv_params(gnutls_session_t session,
+						 const uint8_t * data,
+						 size_t data_size);
+static int _gnutls_record_size_limit_send_params(gnutls_session_t session,
+						 gnutls_buffer_st * extdata);
+
+const hello_ext_entry_st ext_mod_record_size_limit = {
+	.name = "Record Size Limit",
+	.tls_id = 28,
+	.gid = GNUTLS_EXTENSION_RECORD_SIZE_LIMIT,
+	.parse_type = GNUTLS_EXT_TLS,
+	.validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_DTLS | GNUTLS_EXT_FLAG_CLIENT_HELLO |
+		    GNUTLS_EXT_FLAG_EE,
+	.recv_func = _gnutls_record_size_limit_recv_params,
+	.send_func = _gnutls_record_size_limit_send_params
+};
+
+static int
+_gnutls_record_size_limit_recv_params(gnutls_session_t session,
+				      const uint8_t * data, size_t _data_size)
+{
+	ssize_t new_size;
+	ssize_t data_size = _data_size;
+
+	DECR_LEN(data_size, 2);
+	new_size = _gnutls_read_uint16(data);
+
+	/* treat receipt of a smaller value as a fatal error */
+	if (new_size < MIN_RECORD_SIZE)
+		return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
+
+	session->internals.hsk_flags |= HSK_RECORD_SIZE_LIMIT_NEGOTIATED;
+
+	/* if a larger record size limit than the protocol limit is
+	 * provided by the peer, ignore it and stick to the default */
+	if (unlikely(new_size > DEFAULT_MAX_RECORD_SIZE))
+		return gnutls_assert_val(0);
+
+	session->security_parameters.max_record_send_size = new_size;
+	session->security_parameters.max_record_recv_size = new_size;
+
+	return 0;
+}
+
+/* returns data_size or a negative number on failure
+ */
+static int
+_gnutls_record_size_limit_send_params(gnutls_session_t session,
+				      gnutls_buffer_st * extdata)
+{
+	int ret;
+
+	assert(session->security_parameters.max_record_send_size >= 64 &&
+	       session->security_parameters.max_record_send_size <=
+	       DEFAULT_MAX_RECORD_SIZE);
+
+	ret = _gnutls_buffer_append_prefix(extdata, 16,
+					   session->security_parameters.max_record_send_size);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+
+	return 2;
+}
diff --git a/lib/ext/record_size_limit.h b/lib/ext/record_size_limit.h
new file mode 100644
index 0000000000..16e027c6c9
--- /dev/null
+++ b/lib/ext/record_size_limit.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Daiki Ueno
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser 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/>
+ *
+ */
+
+#ifndef EXT_RECORD_SIZE_LIMIT_H
+#define EXT_RECORD_SIZE_LIMIT_H
+
+#include <hello_ext.h>
+
+extern const hello_ext_entry_st ext_mod_record_size_limit;
+
+#endif
diff --git a/lib/gnutls_int.h b/lib/gnutls_int.h
index f4dc71bb3c..dfec39ec33 100644
--- a/lib/gnutls_int.h
+++ b/lib/gnutls_int.h
@@ -201,6 +201,8 @@ typedef enum record_send_state_t {
 #define RECORD_HEADER_SIZE(session) (IS_DTLS(session) ? DTLS_RECORD_HEADER_SIZE : TLS_RECORD_HEADER_SIZE)
 #define MAX_RECORD_HEADER_SIZE DTLS_RECORD_HEADER_SIZE
 
+#define MIN_RECORD_SIZE 512
+
 /* The following macro is used to calculate the overhead when sending.
  * when receiving we use a different way as there are implementations that
  * store more data than allowed.
@@ -343,6 +345,7 @@ typedef enum extensions_t {
 	GNUTLS_EXTENSION_COOKIE,
 	GNUTLS_EXTENSION_EARLY_DATA,
 	GNUTLS_EXTENSION_PSK_KE_MODES,
+	GNUTLS_EXTENSION_RECORD_SIZE_LIMIT,
 	/*
 	 * pre_shared_key and dumbfw must always be the last extensions,
 	 * in that order */
@@ -1300,6 +1303,7 @@ typedef struct {
 #define HSK_TICKET_RECEIVED (1<<20) /* client: a session ticket was received */
 #define HSK_EARLY_START_USED (1<<21)
 #define HSK_EARLY_DATA_IN_FLIGHT (1<<22) /* server: early_data extension was seen in ClientHello */
+#define HSK_RECORD_SIZE_LIMIT_NEGOTIATED (1<<23)
 
 	/* The hsk_flags are for use within the ongoing handshake;
 	 * they are reset to zero prior to handshake start by gnutls_handshake. */
diff --git a/lib/hello_ext.c b/lib/hello_ext.c
index 6197dd5664..9e30bd5413 100644
--- a/lib/hello_ext.c
+++ b/lib/hello_ext.c
@@ -52,6 +52,7 @@
 #include <ext/etm.h>
 #include <ext/cookie.h>
 #include <ext/early_data.h>
+#include <ext/record_size_limit.h>
 #include "extv.h"
 #include <num.h>
 
@@ -92,6 +93,9 @@ static hello_ext_entry_st const *extfunc[MAX_EXT_TYPES+1] = {
 #endif
 	[GNUTLS_EXTENSION_PSK_KE_MODES] = &ext_psk_ke_modes,
 	[GNUTLS_EXTENSION_PRE_SHARED_KEY] = &ext_pre_shared_key,
+	[GNUTLS_EXTENSION_RECORD_SIZE_LIMIT] = &ext_mod_record_size_limit,
+	/* This must be the last extension registered.
+	 */
 	[GNUTLS_EXTENSION_DUMBFW] = &ext_mod_dumbfw,
 };
 
diff --git a/lib/record.c b/lib/record.c
index f0bf192cb8..745969a732 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -46,7 +46,6 @@
 #include "record.h"
 #include "datum.h"
 #include "constate.h"
-#include "ext/max_record.h"
 #include "tls13/key_update.h"
 #include <ext/heartbeat.h>
 #include <state.h>
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 646aa819bd..3a42b90bf9 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -202,7 +202,7 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 ip-check mini-x509-ipaddr trust-store base64-raw random-art dhex509self \
 	 dss-sig-val sign-pk-api tls-session-ext-override record-pad \
 	 tls13-server-kx-neg gnutls_ext_raw_parse_dtls key-export-pkcs8 \
-	 null_retrieve_function
+	 null_retrieve_function tls-record-size-limit
 
 if HAVE_SECCOMP_TESTS
 ctests += dtls-with-seccomp tls-with-seccomp dtls-client-with-seccomp tls-client-with-seccomp
diff --git a/tests/tls-record-size-limit.c b/tests/tls-record-size-limit.c
new file mode 100644
index 0000000000..7a56c0ec64
--- /dev/null
+++ b/tests/tls-record-size-limit.c
@@ -0,0 +1,434 @@
+/*
+ * Copyright (C) 2015 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 General Public License
+ * along with GnuTLS; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <gnutls/gnutls.h>
+#include "utils.h"
+
+#define SKIP16(pos, total) { \
+	uint16_t _s; \
+	if (pos+2 > total) fail("error\n"); \
+	_s = (msg->data[pos] << 8) | msg->data[pos+1]; \
+	if ((size_t)(pos+2+_s) > total) fail("error\n"); \
+	pos += 2+_s; \
+	}
+
+#define SKIP8(pos, total) { \
+	uint8_t _s; \
+	if (pos+1 > total) fail("error\n"); \
+	_s = msg->data[pos]; \
+	if ((size_t)(pos+1+_s) > total) fail("error\n"); \
+	pos += 1+_s; \
+	}
+
+#define HANDSHAKE_SESSION_ID_POS 34
+
+static size_t max_record_size;
+
+#define SERVER_PUSH_ADD if (len > max_record_size + 5+32) fail("max record set to %d, len: %d\n", (int)max_record_size, (int)len);
+#include "eagain-common.h"
+
+#include "cert-common.h"
+
+/* This tests whether the max-record extension is respected on TLS.
+ */
+
+const char *side;
+
+static void tls_log_func(int level, const char *str)
+{
+	fprintf(stderr, "%s|<%d>| %s", side, level, str);
+}
+
+struct handshake_cb_data_st {
+	gnutls_session_t session;
+	bool found_max_record_size;
+	bool found_record_size_limit;
+};
+
+static struct handshake_cb_data_st server_handshake_cb_data;
+static struct handshake_cb_data_st client_handshake_cb_data;
+
+static int ext_callback(void *ctx, unsigned tls_id, const unsigned char *data, unsigned size)
+{
+	struct handshake_cb_data_st *cb_data = ctx;
+	if (tls_id == 1) {	/* max record size */
+		cb_data->found_max_record_size = 1;
+	} else if (tls_id == 28) { /* record size limit */
+		cb_data->found_record_size_limit = 1;
+	}
+	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;
+	unsigned pos;
+	gnutls_datum_t mmsg;
+
+	if (!post)
+		return 0;
+
+	switch (htype) {
+	case GNUTLS_HANDSHAKE_CLIENT_HELLO:
+		assert(msg->size >= HANDSHAKE_SESSION_ID_POS);
+		pos = HANDSHAKE_SESSION_ID_POS;
+		SKIP8(pos, msg->size);
+		SKIP16(pos, msg->size);
+		SKIP8(pos, msg->size);
+
+		mmsg.data = &msg->data[pos];
+		mmsg.size = msg->size - pos;
+		ret = gnutls_ext_raw_parse(&server_handshake_cb_data, ext_callback, &mmsg, 0);
+		assert(ret >= 0);
+		break;
+	case GNUTLS_HANDSHAKE_ENCRYPTED_EXTENSIONS:
+		ret = gnutls_ext_raw_parse(&client_handshake_cb_data, ext_callback, msg, 0);
+		assert(ret >= 0);
+		break;
+	default:
+		abort();
+	}
+	return 0;
+}
+
+#define MAX_BUF 16384
+static char buffer[MAX_BUF];
+
+struct test_ext_st {
+	bool max_record_size;
+	bool record_size_limit;
+};
+
+struct test_st {
+	const char *prio;
+	size_t max_size;
+
+	int expect_error;
+	size_t expect_size;
+	struct test_ext_st expect_server_ext;
+	struct test_ext_st expect_client_ext;
+};
+
+static void check_exts(const struct test_ext_st *exp,
+		       struct handshake_cb_data_st *data)
+{
+	if (exp->max_record_size && !data->found_max_record_size)
+		fail("%s: didn't see max_record_size\n", side);
+	if (!exp->max_record_size && data->found_max_record_size)
+		fail("%s: did see max_record_size\n", side);
+
+	if (exp->record_size_limit && !data->found_record_size_limit)
+		fail("%s: didn't see record_size_limit\n", side);
+	if (!exp->record_size_limit && data->found_record_size_limit)
+		fail("%s: did see record_size_limit\n", side);
+}
+
+static void start(const struct test_st *test)
+{
+	int ret;
+	/* Server stuff. */
+	gnutls_certificate_credentials_t serverx509cred;
+	gnutls_session_t server;
+	int sret = GNUTLS_E_AGAIN;
+	/* Client stuff. */
+	gnutls_certificate_credentials_t clientx509cred;
+	gnutls_session_t client;
+	int cret = GNUTLS_E_AGAIN;
+
+	memset(&server_handshake_cb_data, 0, sizeof(server_handshake_cb_data));
+	memset(&client_handshake_cb_data, 0, sizeof(client_handshake_cb_data));
+
+	global_init();
+
+	/* General init. */
+	gnutls_global_set_log_function(tls_log_func);
+	if (debug)
+		gnutls_global_set_log_level(6);
+
+	/* Init server */
+	gnutls_certificate_allocate_credentials(&serverx509cred);
+	gnutls_certificate_set_x509_key_mem(serverx509cred,
+					    &server2_cert, &server2_key,
+					    GNUTLS_X509_FMT_PEM);
+
+	gnutls_init(&server, GNUTLS_SERVER);
+	gnutls_credentials_set(server, GNUTLS_CRD_CERTIFICATE,
+				serverx509cred);
+
+	gnutls_priority_set_direct(server, test->prio, NULL);
+	gnutls_transport_set_push_function(server, server_push);
+	gnutls_transport_set_pull_function(server, server_pull);
+	gnutls_transport_set_pull_timeout_function(server,
+						   server_pull_timeout_func);
+	gnutls_transport_set_ptr(server, server);
+
+	server_handshake_cb_data.session = server;
+	gnutls_handshake_set_hook_function(server,
+					   GNUTLS_HANDSHAKE_CLIENT_HELLO,
+					   GNUTLS_HOOK_POST,
+					   handshake_callback);
+
+
+	/* Init client */
+
+	ret = gnutls_certificate_allocate_credentials(&clientx509cred);
+	if (ret < 0)
+		exit(1);
+
+	ret = gnutls_certificate_set_x509_trust_mem(clientx509cred, &ca2_cert, GNUTLS_X509_FMT_PEM);
+	if (ret < 0)
+		exit(1);
+
+	ret = gnutls_init(&client, GNUTLS_CLIENT);
+	if (ret < 0)
+		exit(1);
+
+	ret = gnutls_credentials_set(client, GNUTLS_CRD_CERTIFICATE,
+				clientx509cred);
+	if (ret < 0)
+		exit(1);
+
+	ret = gnutls_priority_set_direct(client, test->prio, NULL);
+	if (ret < 0)
+		exit(1);
+
+	ret = gnutls_record_set_max_size(client, test->max_size);
+	if (ret != test->expect_error)
+		fail("unexpected error from gnutls_record_set_max_size()");
+	if (ret == 0)
+		max_record_size = test->max_size;
+	else
+		max_record_size = MAX_BUF;
+
+	gnutls_transport_set_push_function(client, client_push);
+	gnutls_transport_set_pull_function(client, client_pull);
+	gnutls_transport_set_pull_timeout_function(client,
+						   client_pull_timeout_func);
+	gnutls_transport_set_ptr(client, client);
+
+	client_handshake_cb_data.session = client;
+	gnutls_handshake_set_hook_function(client,
+					   GNUTLS_HANDSHAKE_ENCRYPTED_EXTENSIONS,
+					   GNUTLS_HOOK_POST,
+					   handshake_callback);
+
+	HANDSHAKE(client, server);
+
+	memset(buffer, 1, sizeof(buffer));
+	ret = gnutls_record_send(server, buffer, max_record_size + 1);
+	if (ret < 0) {
+		gnutls_perror(ret);
+		exit(1);
+	}
+	if (ret != (int)test->expect_size)
+		fail("unexpected record size sent: %d (%d)\n",
+		     ret, (int)test->expect_size);
+	success("did not send a %d-byte packet\n", (int)max_record_size + 1);
+
+	ret = gnutls_record_send(server, buffer, max_record_size);
+	if (ret < 0) {
+		gnutls_perror(ret);
+		exit(1);
+	}
+	success("did send a %d-byte packet\n", (int)max_record_size);
+
+	gnutls_bye(client, GNUTLS_SHUT_RDWR);
+	gnutls_bye(server, GNUTLS_SHUT_RDWR);
+
+	gnutls_deinit(client);
+	gnutls_deinit(server);
+
+	gnutls_certificate_free_credentials(serverx509cred);
+	gnutls_certificate_free_credentials(clientx509cred);
+
+	gnutls_global_deinit();
+
+	reset_buffers();
+
+	check_exts(&test->expect_server_ext,
+		   &server_handshake_cb_data);
+	check_exts(&test->expect_client_ext,
+		   &client_handshake_cb_data);
+}
+
+static const struct test_st tests[] = {
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.2",
+		.max_size = 511,
+		.expect_error = GNUTLS_E_INVALID_REQUEST,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 0
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.2",
+		.max_size = 512,
+		.expect_error = 0,
+		.expect_size = 512,
+		.expect_server_ext = {
+			.max_record_size = 1,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 0
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.2",
+		.max_size = 8192,
+		.expect_error = 0,
+		.expect_size = 8192,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 0
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.2",
+		.max_size = 16384,
+		.expect_error = 0,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 0
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.2",
+		.max_size = 16385,
+		.expect_error = GNUTLS_E_INVALID_REQUEST,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 0
+		}
+	},
+
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.3",
+		.max_size = 511,
+		.expect_error = GNUTLS_E_INVALID_REQUEST,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		}
+		},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.3",
+		.max_size = 512,
+		.expect_error = 0,
+		.expect_size = 512,
+		.expect_server_ext = {
+			.max_record_size = 1,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.3",
+		.max_size = 8192,
+		.expect_error = 0,
+		.expect_size = 8192,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.3",
+		.max_size = 16384,
+		.expect_error = 0,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		}
+	},
+	{
+		.prio = "NORMAL:-VERS-ALL:+VERS-TLS1.3",
+		.max_size = 16385,
+		.expect_error = GNUTLS_E_INVALID_REQUEST,
+		.expect_size = 16384,
+		.expect_server_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		},
+		.expect_client_ext = {
+			.max_record_size = 0,
+			.record_size_limit = 1
+		}
+	}
+};
+
+void doit(void)
+{
+	size_t i;
+	for (i = 0; i < sizeof(tests)/sizeof(tests[0]); i++)
+		start(&tests[i]);
+}
diff --git a/tests/tls13/prf.c b/tests/tls13/prf.c
index 61b96b246b..dc34973e8f 100644
--- a/tests/tls13/prf.c
+++ b/tests/tls13/prf.c
@@ -126,10 +126,10 @@ static void dump(const char *name, const uint8_t *data, unsigned data_size)
 	} \
 	}
 
-#define KEY_EXP_VALUE "\x2b\x6f\x94\xc8\xbc\xa0\x59\x4b\x61\xc8\x23\x12\x01\x8e\xb2\x3a\xdf\x48\x06\x98\x96\xaf\xf9\xe7\xcf\xd5\xa4\x56\x29\x6b\x84\xd3\xfc\x81"
-#define HELLO_VALUE "\x93\x78\x2d\x00\x88\x02\xd8\xd1\x75\xfe\x1d\xae\x99\x13\xf4\x36\xe0\x10\xc9\xfc\xae\xb8\xc0\x72\xd2\x99\x6e\xc3\x71\xf5\x1b"
-#define CONTEXT_VALUE "\x1e\x95\x2e\xa5\xb9\xff\xe4\xb0\xbe\xa3\x8b\x1f\x6c\x31\x74\x62\x4f\x9d\x0b\xf8\x1d\x5f\x3d\xa5\xa7\x45\x07\x99\xea\xfc\xa2"
-#define NULL_CONTEXT_VALUE "\x2f\x7e\x07\x52\xd4\x23\x0b\x7a\xa0\x7e\x2f\xad\xb5\xcc\xcf\x63\x8f\x6c\x27\x7e\xbb\x9e\xb8\xd3\xa0\x92\x3d\xd0\xaa\xe4\xb0"
+#define KEY_EXP_VALUE "\x42\xba\x1d\x14\x6d\x09\x4f\x64\x7a\x65\xc0\x39\xf8\xd6\x98\xa7\x71\xcd\xb5\xd1\x8d\xf7\x70\xca\x22\x2d\xad\x3f\xac\x47\xe9\x13\xfa\xd0"
+#define HELLO_VALUE "\x0a\xc9\xa4\x5b\xf8\x19\x07\x1c\x56\x61\x7f\xcf\x71\x8b\xff\x0d\xc3\x74\xd7\xf3\x12\xd8\xde\xa8\x33\xcb\x3d\xf3\xc2\x78\x51"
+#define CONTEXT_VALUE "\x7c\x89\xaf\x6f\x98\xbd\xa4\xc4\xad\x10\x54\xc2\x6d\x87\xb3\x94\x02\x62\x2f\x1f\x64\x82\x10\x30\xb6\x49\x08\x2f\x0d\x82\xc1"
+#define NULL_CONTEXT_VALUE "\xa6\xf4\x67\x86\x16\x06\xd0\x53\xcf\x19\xc7\x26\xa4\x94\xc4\x78\xea\xeb\x51\x8e\x04\x0b\x53\xaf\x9f\xde\x0b\xe8\xc3\x08\x04"
 static void check_prfs(gnutls_session_t session)
 {
 	unsigned char key_material[512];