Provide the option to retry or return after post-handshake messages.

In TLSv1.3 post-handshake handshake messages are used for key updates and
session tickets. These are in-band and mean that when the upper layer goes
to read application data, we can end up reading and having to process
handshake messages - this option changes whether we retry and read the
next TLS record, or if we return, signalling that we want more data to
be available.

ok beck@ inoguchi@ tb@

2 files changed, 16 insertions, 4 deletions

diff --git a/src/lib/libssl/tls13_internal.h b/src/lib/libssl/tls13_internal.h
index 7e188981f4..770c18d6ad 100644
--- a/src/lib/libssl/tls13_internal.h
+++ b/src/lib/libssl/tls13_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_internal.h,v 1.81 2020/05/19 01:30:34 beck Exp $ */
+/* $OpenBSD: tls13_internal.h,v 1.82 2020/05/23 11:57:41 jsing Exp $ */
 /*
  * Copyright (c) 2018 Bob Beck <beck@openbsd.org>
  * Copyright (c) 2018 Theo Buehler <tb@openbsd.org>
@@ -198,6 +198,7 @@ void tls13_record_layer_set_hash(struct tls13_record_layer *rl,
     const EVP_MD *hash);
 void tls13_record_layer_set_legacy_version(struct tls13_record_layer *rl,
     uint16_t version);
+void tls13_record_layer_set_retry_after_phh(struct tls13_record_layer *rl, int retry);
 void tls13_record_layer_handshake_completed(struct tls13_record_layer *rl);
 int tls13_record_layer_set_read_traffic_key(struct tls13_record_layer *rl,
     struct tls13_secret *read_key);
diff --git a/src/lib/libssl/tls13_record_layer.c b/src/lib/libssl/tls13_record_layer.c
index 2188d517a8..658a6d6a9e 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 1.44 2020/05/20 14:58:33 beck Exp $ */
+/* $OpenBSD: tls13_record_layer.c,v 1.45 2020/05/23 11:57:41 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -34,6 +34,7 @@ struct tls13_record_layer {
         int handshake_completed;
         int legacy_alerts_allowed;
         int phh;
+        int phh_retry;
 
         /*
          * Read and/or write channels are closed due to an alert being
@@ -233,6 +234,12 @@ tls13_record_layer_handshake_completed(struct tls13_record_layer *rl)
         rl->handshake_completed = 1;
 }
 
+void
+tls13_record_layer_set_retry_after_phh(struct tls13_record_layer *rl, int retry)
+{
+        rl->phh_retry = retry;
+}
+
 static ssize_t
 tls13_record_layer_process_alert(struct tls13_record_layer *rl)
 {
@@ -930,8 +937,12 @@ tls13_record_layer_read_internal(struct tls13_record_layer *rl,
                                  */
                                 rl->phh = 0;
 
-                                if (ret == TLS13_IO_SUCCESS)
-                                        return TLS13_IO_WANT_RETRY;
+                                if (ret == TLS13_IO_SUCCESS) {
+                                        if (rl->phh_retry)
+                                                return TLS13_IO_WANT_RETRY;
+
+                                        return TLS13_IO_WANT_POLLIN;
+                                }
 
                                 return ret;
                         }