session tickets: check timestamp for validitytmp-session-ticket-key-rotation-ajuaristi

We were previously only relying on the client's view of the
ticket lifetime for TLS1.3 tickets. This makes sure that we
only resume tickets that the server considers valid and consolidates
the expiration time checks to _gnutls_check_resumed_params().

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

4 files changed, 29 insertions, 28 deletions

diff --git a/lib/db.c b/lib/db.c
index 38225d31f5..a029f351cd 100644
--- a/lib/db.c
+++ b/lib/db.c
@@ -260,12 +260,28 @@ int _gnutls_server_register_current_session(gnutls_session_t session)
 
 int _gnutls_check_resumed_params(gnutls_session_t session)
 {
-	if (session->internals.resumed_security_parameters.ext_master_secret != 
-	    session->security_parameters.ext_master_secret)
-	    return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
-
-	if (!_gnutls_server_name_matches_resumed(session))
-	    return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+	time_t timestamp = gnutls_time(0);
+	const version_entry_st *vers;
+
+	/* check whether the session is expired */
+	if (timestamp -
+	    session->internals.resumed_security_parameters.timestamp >
+	    session->internals.expire_time
+	    || session->internals.resumed_security_parameters.timestamp >
+	    timestamp)
+		return gnutls_assert_val(GNUTLS_E_EXPIRED);
+
+	/* check various parameters applicable to resumption in TLS1.2 or earlier
+	 */
+	vers = get_version(session);
+	if (!vers || !vers->tls13_sem) {
+		if (session->internals.resumed_security_parameters.ext_master_secret !=
+		    session->security_parameters.ext_master_secret)
+			return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+
+		if (!_gnutls_server_name_matches_resumed(session))
+			return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+	}
 
 	return 0;
 }
@@ -311,7 +327,6 @@ _gnutls_server_restore_session(gnutls_session_t session,
 		return GNUTLS_E_INVALID_SESSION;
 	}
 
-	/* expiration check is performed inside */
 	ret = gnutls_session_set_data(session, data.data, data.size);
 	gnutls_free(data.data);
 
@@ -320,6 +335,7 @@ _gnutls_server_restore_session(gnutls_session_t session,
 		return ret;
 	}
 
+	/* expiration check is performed inside */
 	ret = _gnutls_check_resumed_params(session);
 	if (ret < 0)
 		return gnutls_assert_val(ret);
diff --git a/lib/ext/session_ticket.c b/lib/ext/session_ticket.c
index 177135e642..3eb63818b9 100644
--- a/lib/ext/session_ticket.c
+++ b/lib/ext/session_ticket.c
@@ -349,7 +349,6 @@ static int
 unpack_session(gnutls_session_t session, const gnutls_datum_t *state)
 {
 	int ret;
-	time_t timestamp = gnutls_time(0);
 
 	if (unlikely(!state))
 		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
@@ -358,13 +357,6 @@ unpack_session(gnutls_session_t session, const gnutls_datum_t *state)
 	if (ret < 0)
 		return gnutls_assert_val(ret);
 
-	if (timestamp -
-	    session->internals.resumed_security_parameters.timestamp >
-	    session->internals.expire_time
-	    || session->internals.resumed_security_parameters.timestamp >
-	    timestamp)
-		return gnutls_assert_val(GNUTLS_E_EXPIRED);
-
 	ret = _gnutls_check_resumed_params(session);
 	if (ret < 0)
 		return gnutls_assert_val(ret);
diff --git a/lib/session_pack.c b/lib/session_pack.c
index f8b1830568..c5801fb32e 100644
--- a/lib/session_pack.c
+++ b/lib/session_pack.c
@@ -960,8 +960,6 @@ unpack_security_parameters(gnutls_session_t session, gnutls_buffer_st * ps)
 	session->internals.resumed_security_parameters.timestamp =
 	    timestamp;
 
-	timestamp = gnutls_time(0);
-
 	BUFFER_POP_NUM(ps,
 		       session->internals.resumed_security_parameters.
 		       entity);
@@ -1071,15 +1069,6 @@ unpack_security_parameters(gnutls_session_t session, gnutls_buffer_st * ps)
 		}
 	}
 
-	if (timestamp -
-	    session->internals.resumed_security_parameters.timestamp >
-	    session->internals.expire_time
-	    || session->internals.resumed_security_parameters.timestamp >
-	    timestamp) {
-		gnutls_assert();
-		return GNUTLS_E_EXPIRED;
-	}
-
 	ret = 0;
 
       error:
diff --git a/lib/tls13/session_ticket.c b/lib/tls13/session_ticket.c
index 8087ba7a8b..36d5dc5260 100644
--- a/lib/tls13/session_ticket.c
+++ b/lib/tls13/session_ticket.c
@@ -31,6 +31,7 @@
 #include "auth/cert.h"
 #include "tls13/session_ticket.h"
 #include "session_pack.h"
+#include "db.h"
 
 static int
 pack_ticket(gnutls_session_t session, tls13_ticket_t *ticket, gnutls_datum_t *packed)
@@ -422,9 +423,12 @@ int _gnutls13_unpack_session_ticket(gnutls_session_t session,
 	/* Return ticket parameters */
 	ret = unpack_ticket(session, &decrypted, ticket_data);
 	_gnutls_free_datum(&decrypted);
-	if (ret < 0) {
+	if (ret < 0)
 		return ret;
-	}
+
+	ret = _gnutls_check_resumed_params(session);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
 
 	return 0;
 }