Only permit CCS messages if requesting middlebox compatibility mode.

Currently the TLSv1.3 client always permits the server to send CCS
messages. Be more strict and only permit this if the client is actually
requesitng middlebox compatibility mode.

ok tb@

diff --git a/lib/libssl/tls13_client.c b/lib/libssl/tls13_client.c
index 8775963..33ef55d 100644 (file)
--- a/lib/libssl/tls13_client.c
+++ b/lib/libssl/tls13_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_client.c,v 1.98 2022/08/17 07:39:19 jsing Exp $ */
+/* $OpenBSD: tls13_client.c,v 1.99 2022/09/11 14:33:07 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -148,12 +148,12 @@ tls13_client_hello_send(struct tls13_ctx *ctx, CBB *cbb)
 int
 tls13_client_hello_sent(struct tls13_ctx *ctx)
 {
-       tls13_record_layer_allow_ccs(ctx->rl, 1);
-
        tls1_transcript_freeze(ctx->ssl);
 
-       if (ctx->middlebox_compat)
+       if (ctx->middlebox_compat) {
+               tls13_record_layer_allow_ccs(ctx->rl, 1);
                ctx->send_dummy_ccs = 1;
+       }
 
        return 1;
 }