Add record version checks.

When legacy version is below TLSv1.2 ensure that the record version is
SSL3/TLS, however when the legacy version is set to TLSv1.2 require this
specifically.

ok beck@ tb@

1 files changed, 12 insertions, 5 deletions

diff --git a/src/lib/libssl/tls13_record_layer.c b/src/lib/libssl/tls13_record_layer.c
index e7650b1ecc..8ca52d0b7f 100644
--- a/src/lib/libssl/tls13_record_layer.c
+++ b/src/lib/libssl/tls13_record_layer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_record_layer.c,v 1.39 2020/05/11 17:46:46 jsing Exp $ */
+/* $OpenBSD: tls13_record_layer.c,v 1.40 2020/05/11 18:03:51 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -769,11 +769,18 @@ tls13_record_layer_read_record(struct tls13_record_layer *rl)
                         goto err;
         }
 
-        if ((ret = tls13_record_recv(rl->rrec, rl->cb.wire_read, rl->cb_arg)) <= 0)
+        if ((ret = tls13_record_recv(rl->rrec, rl->cb.wire_read, rl->cb_arg)) <= 0) {
+                switch (ret) {
+                case TLS13_IO_RECORD_VERSION:
+                        return tls13_send_alert(rl, SSL_AD_PROTOCOL_VERSION);
+                }
                 return ret;
-
-        /* XXX - record version checks. */
-
+        }
+ 
+        if (rl->legacy_version == TLS1_2_VERSION &&
+            tls13_record_version(rl->rrec) != TLS1_2_VERSION)
+                return tls13_send_alert(rl, SSL_AD_PROTOCOL_VERSION);
+ 
         content_type = tls13_record_content_type(rl->rrec);
 
         /*