Rework setting next cipher suite

Only update cipher_suite if all internal check succeed and next epoch
will use this ciphe suite. Also while we are at at, actually check for
_gnutls_set_cipher_suite() return value.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

3 files changed, 26 insertions, 40 deletions

diff --git a/lib/constate.c b/lib/constate.c
index 07140c8748..41071eaa69 100644
--- a/lib/constate.c
+++ b/lib/constate.c
@@ -231,8 +231,8 @@ _gnutls_init_record_state(record_parameters_st * params,
 }
 
 int
-_gnutls_epoch_set_cipher_suite(gnutls_session_t session,
-			       int epoch_rel, const uint8_t suite[2])
+_gnutls_set_cipher_suite(gnutls_session_t session,
+			 const uint8_t suite[2])
 {
 	const cipher_entry_st *cipher_algo;
 	const mac_entry_st *mac_algo;
@@ -240,7 +240,7 @@ _gnutls_epoch_set_cipher_suite(gnutls_session_t session,
 	const gnutls_cipher_suite_entry_st *cs;
 	int ret;
 
-	ret = _gnutls_epoch_get(session, epoch_rel, &params);
+	ret = _gnutls_epoch_get(session, EPOCH_NEXT, &params);
 	if (ret < 0)
 		return gnutls_assert_val(ret);
 
@@ -274,6 +274,7 @@ _gnutls_epoch_set_cipher_suite(gnutls_session_t session,
 		session->security_parameters.prf_mac = GNUTLS_MAC_MD5_SHA1;
 	}
 
+	memcpy(session->security_parameters.cipher_suite, suite, 2);
 	params->cipher = cipher_algo;
 	params->mac = mac_algo;
 
diff --git a/lib/constate.h b/lib/constate.h
index bfec4534bb..9f0128b7e1 100644
--- a/lib/constate.h
+++ b/lib/constate.h
@@ -23,8 +23,8 @@
 #ifndef GNUTLS_CONSTATE_H
 #define GNUTLS_CONSTATE_H
 
-int _gnutls_epoch_set_cipher_suite(gnutls_session_t session, int epoch_rel,
-				   const uint8_t suite[2]);
+int _gnutls_set_cipher_suite(gnutls_session_t session,
+			     const uint8_t suite[2]);
 int _gnutls_epoch_set_compression(gnutls_session_t session, int epoch_rel,
 				  gnutls_compression_method_t comp_algo);
 int _gnutls_epoch_get_compression(gnutls_session_t session, int epoch_rel);
diff --git a/lib/handshake.c b/lib/handshake.c
index 4b73842403..eefd816af4 100644
--- a/lib/handshake.c
+++ b/lib/handshake.c
@@ -135,17 +135,14 @@ static int resume_copy_required_values(gnutls_session_t session)
 	 * That is because the client must see these in our
 	 * hello message.
 	 */
-	memcpy(session->security_parameters.cipher_suite,
-	       session->internals.resumed_security_parameters.cipher_suite,
-	       2);
 	session->security_parameters.compression_method =
 	    session->internals.resumed_security_parameters.
 	    compression_method;
 
-	ret = _gnutls_epoch_set_cipher_suite(session, EPOCH_NEXT,
-					     session->internals.
-					     resumed_security_parameters.
-					     cipher_suite);
+	ret = _gnutls_set_cipher_suite(session,
+				       session->internals.
+				       resumed_security_parameters.
+				       cipher_suite);
 	if (ret < 0)
 		return gnutls_assert_val(ret);
 
@@ -987,17 +984,9 @@ _gnutls_server_select_suite(gnutls_session_t session, uint8_t * data,
 					     session,
 					     _gnutls_cipher_suite_get_name
 					     (&data[j]));
-					memcpy(session->
-					       security_parameters.
-					       cipher_suite,
-					       &cipher_suites[i], 2);
-					_gnutls_epoch_set_cipher_suite
-					    (session, EPOCH_NEXT,
-					     session->security_parameters.
-					     cipher_suite);
-
+					retval = _gnutls_set_cipher_suite
+					    (session, &data[j]);
 
-					retval = 0;
 					goto finish;
 				}
 			}
@@ -1013,17 +1002,9 @@ _gnutls_server_select_suite(gnutls_session_t session, uint8_t * data,
 					     session,
 					     _gnutls_cipher_suite_get_name
 					     (&data[j]));
-					memcpy(session->
-					       security_parameters.
-					       cipher_suite,
-					       &cipher_suites[i], 2);
-					_gnutls_epoch_set_cipher_suite
-					    (session, EPOCH_NEXT,
-					     session->security_parameters.
-					     cipher_suite);
-
+					retval = _gnutls_set_cipher_suite
+					    (session, &data[j]);
 
-					retval = 0;
 					goto finish;
 				}
 			}
@@ -1546,6 +1527,7 @@ set_client_ciphersuite(gnutls_session_t session, uint8_t suite[2])
 	uint8_t cipher_suites[MAX_CIPHERSUITE_SIZE];
 	int cipher_suite_size;
 	int i;
+	int ret;
 
 	z = 1;
 	cipher_suite_size =
@@ -1572,10 +1554,9 @@ set_client_ciphersuite(gnutls_session_t session, uint8_t suite[2])
 		return GNUTLS_E_UNKNOWN_CIPHER_SUITE;
 	}
 
-	memcpy(session->security_parameters.cipher_suite, suite, 2);
-	_gnutls_epoch_set_cipher_suite(session, EPOCH_NEXT,
-				       session->security_parameters.
-				       cipher_suite);
+	ret = _gnutls_set_cipher_suite(session, suite);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
 
 	_gnutls_handshake_log("HSK[%p]: Selected cipher suite: %s\n",
 			      session,
@@ -1668,6 +1649,7 @@ client_check_if_resuming(gnutls_session_t session,
 				 uint8_t * session_id, int session_id_len)
 {
 	char buf[2 * GNUTLS_MAX_SESSION_ID_SIZE + 1];
+	int ret;
 
 	_gnutls_handshake_log("HSK[%p]: SessionID length: %d\n", session,
 			      session_id_len);
@@ -1693,15 +1675,17 @@ client_check_if_resuming(gnutls_session_t session,
 		       session->security_parameters.client_random,
 		       GNUTLS_RANDOM_SIZE);
 
-		memcpy(session->security_parameters.cipher_suite,
-			session->internals.resumed_security_parameters.cipher_suite, 2);
 		session->security_parameters.compression_method =
 			session->internals.resumed_security_parameters.compression_method;
 
-		_gnutls_epoch_set_cipher_suite
-		    (session, EPOCH_NEXT,
+		ret = _gnutls_set_cipher_suite
+		    (session,
 		     session->internals.resumed_security_parameters.
 		     cipher_suite);
+		if (ret < 0) {
+			gnutls_assert();
+			goto no_resume;
+		}
 		_gnutls_epoch_set_compression(session, EPOCH_NEXT,
 					      session->internals.
 					      resumed_security_parameters.
@@ -1711,6 +1695,7 @@ client_check_if_resuming(gnutls_session_t session,
 
 		return 0;
 	} else {
+no_resume:
 		/* keep the new session id */
 		session->internals.resumed = RESUME_FALSE;	/* we are not resuming */
 		session->security_parameters.session_id_size =