Remove TLSv1.3 tickets from the client cache as we use them
authorMatt Caswell <matt@openssl.org>
Tue, 26 Jun 2018 17:07:56 +0000 (18:07 +0100)
committerMatt Caswell <matt@openssl.org>
Tue, 3 Jul 2018 08:44:46 +0000 (09:44 +0100)
Tickets are supposed to be single use so we remove them from the cache on
use.

Fixes #6377

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/6601)

ssl/statem/statem_clnt.c
ssl/statem/statem_lib.c
test/sslapitest.c

index 26be9cb..88c3437 100644 (file)
@@ -2682,6 +2682,7 @@ MSG_PROCESS_RETURN tls_process_new_session_ticket(SSL *s, PACKET *pkt)
         goto err;
     }
     s->session->session_id_length = sess_len;
+    s->session->not_resumable = 0;
 
     /* This is a standalone message in TLSv1.3, so there is no more to read */
     if (SSL_IS_TLS13(s)) {
index 91d304e..61fc3ca 100644 (file)
@@ -1068,12 +1068,21 @@ WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst, int clearbufs, int stop)
                 dtls1_start_timer(s);
             }
         } else {
-            /*
-             * In TLSv1.3 we update the cache as part of processing the
-             * NewSessionTicket
-             */
-            if (!SSL_IS_TLS13(s))
+            if (SSL_IS_TLS13(s)) {
+                /*
+                 * We encourage applications to only use TLSv1.3 tickets once,
+                 * so we remove this one from the cache.
+                 */
+                if ((s->session_ctx->session_cache_mode
+                     & SSL_SESS_CACHE_CLIENT) != 0)
+                    SSL_CTX_remove_session(s->session_ctx, s->session);
+            } else {
+                /*
+                 * In TLSv1.3 we update the cache as part of processing the
+                 * NewSessionTicket
+                 */
                 ssl_update_cache(s, SSL_SESS_CACHE_CLIENT);
+            }
             if (s->hit)
                 CRYPTO_atomic_add(&s->session_ctx->stats.sess_hit, 1, &discard,
                                   s->session_ctx->lock);
index 6e08795..598b02a 100644 (file)
@@ -944,11 +944,12 @@ static int execute_test_session(int maxprot, int use_int_cache,
     if (maxprot == TLS1_3_VERSION) {
         /*
          * In TLSv1.3 we should have created a new session even though we have
-         * resumed.
+         * resumed. Since we attempted a resume we should also have removed the
+         * old ticket from the cache so that we try to only use tickets once.
          */
         if (use_ext_cache
                 && (!TEST_int_eq(new_called, 1)
-                    || !TEST_int_eq(remove_called, 0)))
+                    || !TEST_int_eq(remove_called, 1)))
             goto end;
     } else {
         /*