Ensure that a client hello does not have trailing data.

Found by tlsfuzzer.

ok beck@

1 files changed, 4 insertions, 1 deletions

diff --git a/src/lib/libssl/ssl_srvr.c b/src/lib/libssl/ssl_srvr.c
index a473d5af05..3a37fc7e09 100644
--- a/src/lib/libssl/ssl_srvr.c
+++ b/src/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.118 2021/08/30 19:25:43 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.119 2021/09/03 13:18:01 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1017,6 +1017,9 @@ ssl3_get_client_hello(SSL *s)
                 goto fatal_err;
         }
 
+        if (CBS_len(&cbs) != 0)
+                goto decode_err;
+
         if (!S3I(s)->renegotiate_seen && s->internal->renegotiate) {
                 al = SSL_AD_HANDSHAKE_FAILURE;
                 SSLerror(s, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);