Group HelloVerifyRequest decoding and add missing check for trailing data.

ok tb@

diff --git a/lib/libssl/ssl_clnt.c b/lib/libssl/ssl_clnt.c
index 0c7bdbc..680cafa 100644 (file)
--- a/lib/libssl/ssl_clnt.c
+++ b/lib/libssl/ssl_clnt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_clnt.c,v 1.78 2021/02/07 15:26:32 jsing Exp $ */
+/* $OpenBSD: ssl_clnt.c,v 1.79 2021/02/20 08:19:01 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -812,6 +812,10 @@ ssl3_get_dtls_hello_verify(SSL *s)
 
        if (!CBS_get_u16(&hello_verify_request, &ssl_version))
                goto truncated;
+       if (!CBS_get_u8_length_prefixed(&hello_verify_request, &cookie))
+               goto truncated;
+       if (CBS_len(&hello_verify_request) != 0)
+               goto truncated;
 
        if (ssl_version != s->version) {
                SSLerror(s, SSL_R_WRONG_SSL_VERSION);
@@ -820,9 +824,6 @@ ssl3_get_dtls_hello_verify(SSL *s)
                goto f_err;
        }
 
-       if (!CBS_get_u8_length_prefixed(&hello_verify_request, &cookie))
-               goto truncated;
-
        if (!CBS_write_bytes(&cookie, D1I(s)->cookie,
            sizeof(D1I(s)->cookie), &cookie_len)) {
                D1I(s)->cookie_len = 0;