Simplify session ticket parsing/handling.

The original implementation is rather crazy and means that we effectively
have two lots of code that parse a ClientHello and two lots of code that
parse TLS extensions. Partially simplify this by passing a CBS containing
the extension block through to the session handling functions, removing the
need to reimplement the ClientHello parsing.

While here standarise on naming for session_id and session_id_len.

ok inoguchi@ tb@

1 files changed, 7 insertions, 8 deletions

diff --git a/src/lib/libssl/ssl_srvr.c b/src/lib/libssl/ssl_srvr.c
index b9b2c58705..f06491e558 100644
--- a/src/lib/libssl/ssl_srvr.c
+++ b/src/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.44 2018/08/24 17:44:22 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.45 2018/08/24 18:10:25 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -818,7 +818,6 @@ ssl3_get_client_hello(SSL *s)
         unsigned long alg_k;
         const SSL_METHOD *method;
         uint16_t shared_version;
-        unsigned char *end;
 
         /*
          * We do this so that we will respond with our native type.
@@ -842,8 +841,6 @@ ssl3_get_client_hello(SSL *s)
         if (n < 0)
                 goto err;
 
-        end = (unsigned char *)s->internal->init_msg + n;
-
         CBS_init(&cbs, s->internal->init_msg, n);
 
         /* Parse client hello up until the extensions (if any). */
@@ -928,10 +925,12 @@ ssl3_get_client_hello(SSL *s)
                 if (!ssl_get_new_session(s, 1))
                         goto err;
         } else {
-                /* XXX - pass CBS through instead... */
-                i = ssl_get_prev_session(s,
-                    (unsigned char *)CBS_data(&session_id),
-                    CBS_len(&session_id), end);
+                CBS ext_block;
+
+                CBS_dup(&cbs, &ext_block);
+
+                i = ssl_get_prev_session(s, CBS_data(&session_id),
+                    CBS_len(&session_id), &ext_block);
                 if (i == 1) { /* previous session */
                         s->internal->hit = 1;
                 } else if (i == -1)