Merge branch 'tmp-limit-ticket-age' into 'master'

limit the age of session tickets

Closes #476

See merge request gnutls/gnutls!697

9 files changed, 389 insertions, 37 deletions

diff --git a/doc/cha-intro-tls.texi b/doc/cha-intro-tls.texi
index 0c82f0853b..b95abc6b81 100644
--- a/doc/cha-intro-tls.texi
+++ b/doc/cha-intro-tls.texi
@@ -464,6 +464,9 @@ regularly.
 Since version 3.1.3 GnuTLS clients transparently support session tickets,
 unless forward secrecy is explicitly requested (with the PFS priority string).
 
+Under TLS 1.3 session tickets are mandatory for session resumption, and they
+do not share the forward secrecy concerns as with TLS 1.2 or earlier.
+
 @node HeartBeat
 @subsection HeartBeat
 @cindex TLS extensions
diff --git a/lib/constate.c b/lib/constate.c
index b1086fd838..8f15990ad6 100644
--- a/lib/constate.c
+++ b/lib/constate.c
@@ -669,8 +669,8 @@ int _gnutls_epoch_set_keys(gnutls_session_t session, uint16_t epoch, hs_stage_t
 		dst->pversion = src->pversion; \
 		memcpy( dst->session_id, src->session_id, GNUTLS_MAX_SESSION_ID_SIZE); \
 		dst->session_id_size = src->session_id_size; \
-		dst->timestamp = src->timestamp; \
 	} \
+	dst->timestamp = src->timestamp; \
 	dst->cert_type = src->cert_type; \
 	dst->client_auth_type = src->client_auth_type; \
 	dst->server_auth_type = src->server_auth_type
diff --git a/lib/ext/pre_shared_key.c b/lib/ext/pre_shared_key.c
index b12d853af8..dc56d1dc49 100644
--- a/lib/ext/pre_shared_key.c
+++ b/lib/ext/pre_shared_key.c
@@ -201,8 +201,7 @@ client_send_params(gnutls_session_t session,
 	unsigned next_idx;
 	const mac_entry_st *prf_res = NULL;
 	const mac_entry_st *prf_psk = NULL;
-	time_t cur_time;
-	int ticket_age;
+	time_t cur_time, ticket_age;
 	uint32_t ob_ticket_age;
 	int free_username = 0;
 	psk_auth_info_t info = NULL;
@@ -340,6 +339,13 @@ client_send_params(gnutls_session_t session,
 		binders_len += 1 + _gnutls_mac_get_algo_len(prf_psk);
 	}
 
+	/* if no tickets or identities to be sent */
+	if (psk_id_len == 0) {
+		/* reset extensions buffer */
+		extdata->length = spos;
+		return 0;
+	}
+
 	_gnutls_write_uint16(psk_id_len, &extdata->data[spos]);
 
 	binders_pos = extdata->length-spos;
@@ -470,7 +476,7 @@ static int server_recv_params(gnutls_session_t session,
 	struct psk_st psk;
 	psk_auth_info_t info;
 	tls13_ticket_t ticket_data;
-	int ticket_age;
+	time_t ticket_age;
 	bool resuming;
 
 	ret = _gnutls13_psk_ext_parser_init(&psk_parser, data, len);
diff --git a/lib/tls13/session_ticket.c b/lib/tls13/session_ticket.c
index dfe4992669..77edbcda91 100644
--- a/lib/tls13/session_ticket.c
+++ b/lib/tls13/session_ticket.c
@@ -177,9 +177,23 @@ generate_session_ticket(gnutls_session_t session, tls13_ticket_t *ticket)
 	int ret;
 	gnutls_datum_t packed = { NULL, 0 };
 	tls13_ticket_t ticket_data;
+	time_t now = gnutls_time(0);
+
+	if (session->internals.resumed != RESUME_FALSE) {
+		/* If we are resuming ensure that we don't extend the lifetime
+		 * of the ticket past the original session expiration time */
+		if (now >= session->security_parameters.timestamp + session->internals.expire_time)
+			return GNUTLS_E_INT_RET_0; /* don't send ticket */
+		else
+			ticket->lifetime = session->security_parameters.timestamp +
+					   session->internals.expire_time - now;
+	} else {
+		/* Set ticket lifetime to the default expiration time */
+		ticket->lifetime = session->internals.expire_time;
+	}
 
-	/* Generate a random 128-bit ticket nonce */
-	ticket->nonce_size = 16;
+	/* Generate a random 32-bit ticket nonce */
+	ticket->nonce_size = 4;
 
 	if ((ret = gnutls_rnd(GNUTLS_RND_NONCE,
 			ticket->nonce, ticket->nonce_size)) < 0)
@@ -188,8 +202,6 @@ generate_session_ticket(gnutls_session_t session, tls13_ticket_t *ticket)
 	if ((ret = gnutls_rnd(GNUTLS_RND_NONCE, &ticket->age_add, sizeof(uint32_t))) < 0)
 		return gnutls_assert_val(ret);
 
-	/* Set ticket lifetime to 1 day (86400 seconds) */
-	ticket->lifetime = session->internals.expire_time;
 
 	ticket->prf = session->security_parameters.prf;
 
@@ -239,11 +251,16 @@ int _gnutls13_send_session_ticket(gnutls_session_t session, unsigned again)
 	if (again == 0) {
 		memset(&ticket, 0, sizeof(tls13_ticket_t));
 
-		ret = _gnutls_buffer_init_handshake_mbuffer(&buf);
-		if (ret < 0)
+		ret = generate_session_ticket(session, &ticket);
+		if (ret < 0) {
+			if (ret == GNUTLS_E_INT_RET_0) {
+				return gnutls_assert_val(0);
+			}
+
 			return gnutls_assert_val(ret);
+		}
 
-		ret = generate_session_ticket(session, &ticket);
+		ret = _gnutls_buffer_init_handshake_mbuffer(&buf);
 		if (ret < 0) {
 			gnutls_assert();
 			goto cleanup;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c12887d4eb..2ad3b527a4 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -32,7 +32,7 @@ SUBDIRS += suite
 endif
 
 EXTRA_DIST = suppressions.valgrind eagain-common.h cert-common.h test-chains.h \
-	ocsp-common.h cmocka-common.h \
+	ocsp-common.h cmocka-common.h virt-time.h \
 	certs/ca-cert-ecc.pem  certs/cert-ecc256.pem  certs/cert-ecc521.pem \
 	certs/cert-rsa-2432.pem certs/ecc384.pem certs/ecc.pem hex.h \
 	certs/ca-ecc.pem certs/cert-ecc384.pem certs/cert-ecc.pem certs/ecc256.pem \
@@ -143,9 +143,9 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 mini-emsgsize-dtls chainverify-unsorted mini-overhead tls12-ffdhe \
 	 mini-dtls-heartbeat mini-x509-callbacks key-openssl priorities priorities-groups	\
 	 gnutls_x509_privkey_import gnutls_x509_crt_list_import \
-	 sign-verify-ext4 tls-neg-ext4-key \
+	 sign-verify-ext4 tls-neg-ext4-key resume-lifetime \
 	 mini-dtls-srtp rsa-encrypt-decrypt mini-loss-time gnutls-strcodes \
-	 mini-record mini-dtls-record mini-handshake-timeout mini-record-range \
+	 mini-record mini-dtls-record handshake-timeout mini-record-range \
 	 mini-cert-status fips-mode-pthread rsa-psk global-init sec-params sign-verify-data \
 	 fips-test fips-override-test mini-global-load name-constraints x509-extensions \
 	 long-session-id mini-x509-callbacks-intr mini-dtls-lowmtu set_x509_key_file-late \
diff --git a/tests/mini-handshake-timeout.c b/tests/handshake-timeout.c
index b4d1c2c962..c7ff20ca9e 100644
--- a/tests/mini-handshake-timeout.c
+++ b/tests/handshake-timeout.c
@@ -15,9 +15,8 @@
  * 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
+ * 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
@@ -46,6 +45,7 @@ int main()
 #include <gnutls/gnutls.h>
 #include <gnutls/dtls.h>
 #include <signal.h>
+#include <virt-time.h>
 
 #include "utils.h"
 
@@ -156,7 +156,7 @@ static void server(int fd, int wait)
 	gnutls_transport_set_int(session, fd);
 
 	if (wait) {
-		sec_sleep(25);
+		virt_sec_sleep(25);
 	} else {
 		do {
 			ret = gnutls_handshake(session);
@@ -217,6 +217,8 @@ static void ch_handler(int sig)
 
 void doit(void)
 {
+	virt_time_init();
+
 	signal(SIGCHLD, ch_handler);
 	signal(SIGPIPE, SIG_IGN);
 
diff --git a/tests/resume-lifetime.c b/tests/resume-lifetime.c
new file mode 100644
index 0000000000..99c9c5b346
--- /dev/null
+++ b/tests/resume-lifetime.c
@@ -0,0 +1,282 @@
+/*
+ * Copyright (C) 2016-2018 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>
+#include <string.h>
+#include <errno.h>
+#include <gnutls/gnutls.h>
+#include <assert.h>
+#include "utils.h"
+#include "virt-time.h"
+#include "eagain-common.h"
+#include "cert-common.h"
+
+/* This test checks whether the lifetime of a resumed session can
+ * be extended past the designated one */
+
+const char *side;
+
+static void tls_log_func(int level, const char *str)
+{
+	fprintf(stderr, "%s|<%d>| %s", side, level, str);
+}
+
+struct hsk_st {
+	unsigned sent_nst; /* whether the new session ticket was sent */
+	unsigned sent_psk; /* whether the PSK extension was sent */
+	unsigned sleep_at_finished; /* how long to wait at finished message reception */
+
+};
+
+static int ext_hook_func(void *ctx, unsigned tls_id,
+			 const unsigned char *data, unsigned size)
+{
+	if (tls_id == 41) {
+		struct hsk_st *h = ctx;
+		h->sent_psk = 1;
+	}
+	return 0;
+}
+
+static int handshake_callback(gnutls_session_t session, unsigned int htype,
+	unsigned post, unsigned int incoming, const gnutls_datum_t *msg)
+{
+	struct hsk_st *h = gnutls_session_get_ptr(session);
+
+	if (htype == GNUTLS_HANDSHAKE_FINISHED && incoming) {
+		if (h->sleep_at_finished)
+			virt_sec_sleep(h->sleep_at_finished);
+		return 0;
+	} else if (htype == GNUTLS_HANDSHAKE_CLIENT_HELLO) {
+		gnutls_ext_raw_parse(h, ext_hook_func, msg,
+				     GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO);
+	}
+
+	if (htype != GNUTLS_HANDSHAKE_NEW_SESSION_TICKET)
+		return 0;
+
+	if (h)
+		h->sent_nst = 1;
+	return 0;
+}
+
+/* Returns true if resumed */
+static unsigned handshake(const char *prio, unsigned t, const gnutls_datum_t *sdata,
+			  gnutls_datum_t *ndata,
+			  gnutls_datum_t *skey,
+			  struct hsk_st *h)
+{
+	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;
+	char buf[128];
+
+	gnutls_global_set_log_function(tls_log_func);
+	if (debug)
+		gnutls_global_set_log_level(6);
+
+	assert(gnutls_certificate_allocate_credentials(&serverx509cred)>=0);
+	assert(gnutls_certificate_set_x509_key_mem(serverx509cred,
+					    &server_cert, &server_key,
+					    GNUTLS_X509_FMT_PEM)>=0);
+
+	assert(gnutls_init(&server, GNUTLS_SERVER)>=0);
+	gnutls_credentials_set(server, GNUTLS_CRD_CERTIFICATE,
+				serverx509cred);
+	assert(gnutls_priority_set_direct(server, prio, NULL)>=0);
+	gnutls_transport_set_push_function(server, server_push);
+	gnutls_transport_set_pull_function(server, server_pull);
+	gnutls_transport_set_ptr(server, server);
+	gnutls_session_set_ptr(server, h);
+
+	gnutls_db_set_cache_expiration(server, t);
+	assert(gnutls_session_ticket_enable_server(server, skey) >= 0);
+
+	gnutls_handshake_set_hook_function(server, -1,
+					   GNUTLS_HOOK_POST,
+					   handshake_callback);
+
+	assert(gnutls_certificate_allocate_credentials(&clientx509cred)>=0);
+	assert(gnutls_certificate_set_x509_trust_mem(clientx509cred, &ca_cert, GNUTLS_X509_FMT_PEM)>=0);
+	assert(gnutls_init(&client, GNUTLS_CLIENT)>=0);
+
+	assert(gnutls_credentials_set(client, GNUTLS_CRD_CERTIFICATE,
+				      clientx509cred)>=0);
+
+	assert(gnutls_priority_set_direct(client, prio, NULL)>=0);
+	gnutls_transport_set_push_function(client, client_push);
+	gnutls_transport_set_pull_function(client, client_pull);
+	gnutls_transport_set_ptr(client, client);
+
+	if (sdata) {
+		assert(gnutls_session_set_data(client, sdata->data, sdata->size)>=0);
+	}
+
+	memset(buf, 0, sizeof(buf));
+	ret = gnutls_session_set_data(client, buf, sizeof(buf));
+	if (ret != GNUTLS_E_DB_ERROR) {
+		fail("unexpected error: %s\n", gnutls_strerror(ret));
+	}
+
+	HANDSHAKE(client, server);
+
+	gnutls_record_recv(client, buf, sizeof(buf));
+
+	if (ndata) {
+		ret = gnutls_session_get_data2(client, ndata);
+		if (ret < 0) {
+			fail("unexpected error: %s\n", gnutls_strerror(ret));
+		}
+	}
+
+	ret = gnutls_session_is_resumed(client);
+
+	gnutls_deinit(server);
+	gnutls_deinit(client);
+
+	gnutls_certificate_free_credentials(serverx509cred);
+	gnutls_certificate_free_credentials(clientx509cred);
+
+	reset_buffers();
+	return ret;
+}
+
+/* @t is the lifetime of the first ticket, @s is the
+ * time to wait before asking for a ticket the last try */
+static void start(const char *name, const char *prio, unsigned t, unsigned s)
+{
+	gnutls_datum_t sdata, ndata, skey;
+	unsigned ret;
+	struct hsk_st h;
+	memset(&h, 0, sizeof(h));
+
+	success("trying %s\n", name);
+
+	assert(gnutls_session_ticket_key_generate(&skey)>=0);
+
+	/* step1: get a fresh ticket */
+	ret = handshake(prio, t, NULL, &sdata, &skey, &h);
+	assert(ret == 0);
+	assert(h.sent_nst != 0);
+	memset(&h, 0, sizeof(h));
+
+	if (debug)
+		success("completed first handshake\n");
+
+	if (s)
+		virt_sec_sleep(s);
+
+	/* step2: get a ticket from the resumed session of the first */
+	ret = handshake(prio, t, &sdata, &ndata, &skey, &h);
+	assert(ret != 0);
+	assert(h.sent_nst != 0);
+	memset(&h, 0, sizeof(h));
+
+	/* wait until the ticket we got in step1 is invalid, although
+	 * the ticket we got in step2 is valid */
+
+	if (debug)
+		success("completed second handshake\n");
+
+	if (s)
+		virt_sec_sleep(s);
+
+	ret = handshake(prio, t, &ndata, NULL, &skey, &h);
+
+	if (s) {
+		if (ret != 0)
+			fail("server resumed session even if ticket expired!\n");
+
+		/* we shouldn't have sent the PSK extension as the ticket was expired */
+		assert(h.sent_psk == 0);
+	}
+
+	gnutls_free(ndata.data);
+	gnutls_free(sdata.data);
+	gnutls_free(skey.data);
+}
+
+/* @t is the lifetime of the first ticket, @s is the
+ * time to wait before asking for a ticket the last try
+ *
+ * This makes the ticket to expire during handshake (after resumtion),
+ * but before the client receives the new session ticket. In that
+ * case the server shouldn't send a session ticket.
+ */
+static void start2(const char *name, const char *prio, unsigned t, unsigned s)
+{
+	gnutls_datum_t sdata, ndata, skey;
+	unsigned ret;
+	struct hsk_st h;
+	memset(&h, 0, sizeof(h));
+
+	success("trying %s\n", name);
+
+	assert(gnutls_session_ticket_key_generate(&skey)>=0);
+
+	/* step1: get a fresh ticket */
+	ret = handshake(prio, t, NULL, &sdata, &skey, &h);
+	assert(ret == 0);
+	assert(h.sent_nst != 0);
+	memset(&h, 0, sizeof(h));
+
+	/* step2: get a ticket from the resumed session of the first */
+	ret = handshake(prio, t, &sdata, &ndata, &skey, &h);
+	assert(ret != 0);
+	assert(h.sent_nst != 0);
+	memset(&h, 0, sizeof(h));
+
+	/* wait until the ticket we got in step1 is invalid, although
+	 * the ticket we got in step2 is valid */
+
+	if (s)
+		h.sleep_at_finished = s;
+
+	ret = handshake(prio, t, &ndata, NULL, &skey, &h);
+
+	assert(ret != 0);
+	if (h.sent_nst != 0)
+		fail("server sent session ticket even if ticket expired!\n");
+
+	gnutls_free(ndata.data);
+	gnutls_free(sdata.data);
+	gnutls_free(skey.data);
+}
+
+void doit(void)
+{
+	virt_time_init();
+
+	start("TLS1.3 sanity", "NORMAL:-VERS-ALL:+VERS-TLS1.3", 64, 0);
+	start("TLS1.3 ticket extension", "NORMAL:-VERS-ALL:+VERS-TLS1.3", 5, 3);
+	start2("TLS1.3 ticket extension - expires at handshake", "NORMAL:-VERS-ALL:+VERS-TLS1.3", 2, 3);
+}
diff --git a/tests/session-tickets-ok.c b/tests/session-tickets-ok.c
index f33e1967c4..56aae5063c 100644
--- a/tests/session-tickets-ok.c
+++ b/tests/session-tickets-ok.c
@@ -74,7 +74,8 @@ static int handshake_callback(gnutls_session_t session, unsigned int htype,
 	if (htype != GNUTLS_HANDSHAKE_NEW_SESSION_TICKET)
 		return 0;
 
-	success("sent session ticket\n");
+	if (debug)
+		success("sent session ticket\n");
 	sent = 1;
 	return 0;
 }
@@ -86,7 +87,6 @@ static void client(int fd, const char *prio)
 	int ret;
 	gnutls_certificate_credentials_t x509_cred;
 	gnutls_session_t session;
-	/* Need to enable anonymous KX specifically. */
 
 	global_init();
 
@@ -97,31 +97,19 @@ static void client(int fd, const char *prio)
 
 	gnutls_certificate_allocate_credentials(&x509_cred);
 
-	/* Initialize TLS session
-	 */
-	gnutls_init(&session, GNUTLS_CLIENT);
+	assert(gnutls_init(&session, GNUTLS_CLIENT)>=0);
 
-	/* Use default priorities */
-	gnutls_priority_set_direct(session, "NORMAL:-KX-ALL:+ECDHE-RSA", NULL);
+	assert(gnutls_priority_set_direct(session, prio, NULL)>=0);
 
-	/* put the anonymous credentials to the current session
-	 */
 	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
 
 	gnutls_transport_set_int(session, fd);
 
-	/* 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));
 		terminate();
@@ -137,8 +125,6 @@ static void client(int fd, const char *prio)
 
 	gnutls_bye(session, GNUTLS_SHUT_WR);
 
-      end:
-
 	close(fd);
 
 	gnutls_deinit(session);
@@ -193,7 +179,7 @@ static void server(int fd, const char *prio)
 	/* avoid calling all the priority functions, since the defaults
 	 * are adequate.
 	 */
-	assert(gnutls_priority_set_direct(session, "NORMAL", NULL)>=0);
+	assert(gnutls_priority_set_direct(session, prio, NULL)>=0);
 
 	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
 
diff --git a/tests/virt-time.h b/tests/virt-time.h
new file mode 100644
index 0000000000..02c8cdb147
--- /dev/null
+++ b/tests/virt-time.h
@@ -0,0 +1,56 @@
+/*
+ * 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/>
+ */
+
+#ifndef VIRT_TIME_H
+#define VIRT_TIME_H
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <time.h>
+#include <gnutls/gnutls.h>
+
+/* virtualize time in a test. This freezes the time in the test, except for
+ * the advances due to calls to virt_sleep_sec(). This makes the test
+ * independent of the test system load, and avoids any long delays.
+ *
+ * This only affects the parts of the library that utilize gnutls_time(),
+ * not the higher precision gettime */
+static time_t _now = 0;
+
+#define virt_sec_sleep(s) _now += s
+
+#define virt_time_init() { \
+		_now = time(0); \
+		gnutls_global_set_time_function(mytime); \
+	}
+
+
+static time_t mytime(time_t * t)
+{
+	if (t)
+		*t = _now;
+
+	return _now;
+}
+
+#endif