Add read and write support to tls_buffer.

tls_buffer was original created for a specific use case, namely reading in
length prefixed messages. This adds read and write support, along with a
capacity limit, allowing it to be used in additional use cases.

ok beck@ tb@

1 files changed, 3 insertions, 2 deletions

diff --git a/src/lib/libssl/tls13_handshake_msg.c b/src/lib/libssl/tls13_handshake_msg.c
index 946ccaccd6..134cfb2173 100644
--- a/src/lib/libssl/tls13_handshake_msg.c
+++ b/src/lib/libssl/tls13_handshake_msg.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_handshake_msg.c,v 1.5 2022/07/20 06:32:24 jsing Exp $ */
+/* $OpenBSD: tls13_handshake_msg.c,v 1.6 2022/07/22 19:33:53 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -136,7 +136,8 @@ tls13_handshake_msg_recv(struct tls13_handshake_msg *msg,
                     tls13_handshake_msg_read_cb, rl)) <= 0)
                         return ret;
 
-                tls_buffer_cbs(msg->buf, &cbs);
+                if (!tls_buffer_data(msg->buf, &cbs))
+                        return TLS13_IO_FAILURE;
 
                 if (!CBS_get_u8(&cbs, &msg_type))
                         return TLS13_IO_FAILURE;