Send dummy ChangeCipherSpec messages from the TLSv1.3 client.

When operating in middlebox compatibility mode, the TLSv1.3 client needs
to send a dummy ChangeCipherSpec message immediately before its second
flight of handshake messages (when early data is not offered).

ok tb@

1 files changed, 5 insertions, 1 deletions

diff --git a/src/lib/libssl/tls13_client.c b/src/lib/libssl/tls13_client.c
index d5ac6ba5e0..27b2d712ae 100644
--- a/src/lib/libssl/tls13_client.c
+++ b/src/lib/libssl/tls13_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_client.c,v 1.56 2020/05/09 15:30:21 jsing Exp $ */
+/* $OpenBSD: tls13_client.c,v 1.57 2020/05/09 15:47:11 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -150,6 +150,9 @@ tls13_client_hello_sent(struct tls13_ctx *ctx)
 
         tls1_transcript_freeze(ctx->ssl);
 
+        if (ctx->middlebox_compat)
+                ctx->send_dummy_ccs = 1;
+
         return 1;
 }
 
@@ -544,6 +547,7 @@ tls13_server_certificate_request_recv(struct tls13_ctx *ctx, CBS *cbs)
  err:
         if (ctx->alert == 0)
                 ctx->alert = TLS1_AD_DECODE_ERROR;
+
         return 0;
 }