Avoid unbounded memory growth, which can be triggered by a client

repeatedly renegotiating and sending OCSP Status Request TLS extensions.

Fix based on OpenSSL.

1 files changed, 20 insertions, 9 deletions

diff --git a/src/lib/libssl/t1_lib.c b/src/lib/libssl/t1_lib.c
index 6853bc210e..3f66e2e6d0 100644
--- a/src/lib/libssl/t1_lib.c
+++ b/src/lib/libssl/t1_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_lib.c,v 1.89 2016/09/22 06:57:40 guenther Exp $ */
+/* $OpenBSD: t1_lib.c,v 1.90 2016/09/22 12:33:50 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1444,10 +1444,28 @@ ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
                                 /* Read in responder_id_list */
                                 n2s(data, dsize);
                                 size -= 2;
-                                if (dsize > size  ) {
+                                if (dsize > size) {
                                         *al = SSL_AD_DECODE_ERROR;
                                         return 0;
                                 }
+
+                                /*
+                                 * We remove any OCSP_RESPIDs from a
+                                 * previous handshake to prevent
+                                 * unbounded memory growth.
+                                 */
+                                sk_OCSP_RESPID_pop_free(s->tlsext_ocsp_ids,
+                                    OCSP_RESPID_free);
+                                s->tlsext_ocsp_ids = NULL;
+                                if (dsize > 0) {
+                                        s->tlsext_ocsp_ids =
+                                            sk_OCSP_RESPID_new_null();
+                                        if (s->tlsext_ocsp_ids == NULL) {
+                                                *al = SSL_AD_INTERNAL_ERROR;
+                                                return 0;
+                                        }
+                                }
+
                                 while (dsize > 0) {
                                         OCSP_RESPID *id;
                                         int idsize;
@@ -1475,13 +1493,6 @@ ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
                                                 *al = SSL_AD_DECODE_ERROR;
                                                 return 0;
                                         }
-                                        if (!s->tlsext_ocsp_ids &&
-                                            !(s->tlsext_ocsp_ids =
-                                            sk_OCSP_RESPID_new_null())) {
-                                                OCSP_RESPID_free(id);
-                                                *al = SSL_AD_INTERNAL_ERROR;
-                                                return 0;
-                                        }
                                         if (!sk_OCSP_RESPID_push(
                                             s->tlsext_ocsp_ids, id)) {
                                                 OCSP_RESPID_free(id);