1 files changed, 29 insertions, 3 deletions

diff --git a/src/lib/libssl/tls13_handshake.c b/src/lib/libssl/tls13_handshake.c
index 310a2116b8..cca8560fc2 100644
--- a/src/lib/libssl/tls13_handshake.c
+++ b/src/lib/libssl/tls13_handshake.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: tls13_handshake.c,v 1.69 2021/07/01 17:53:39 jsing Exp $      */
+/*      $OpenBSD: tls13_handshake.c,v 1.70 2021/09/16 19:25:30 jsing Exp $      */
 /*
  * Copyright (c) 2018-2021 Theo Buehler <tb@openbsd.org>
  * Copyright (c) 2019 Joel Sing <jsing@openbsd.org>
@@ -331,6 +331,18 @@ tls13_handshake_advance_state_machine(struct tls13_ctx *ctx)
         return 1;
 }
 
+static int
+tls13_handshake_end_of_flight(struct tls13_ctx *ctx,
+    const struct tls13_handshake_action *previous)
+{
+        const struct tls13_handshake_action *current;
+
+        if ((current = tls13_handshake_active_action(ctx)) == NULL)
+                return 1;
+
+        return current->sender != previous->sender;
+}
+
 int
 tls13_handshake_msg_record(struct tls13_ctx *ctx)
 {
@@ -344,6 +356,7 @@ int
 tls13_handshake_perform(struct tls13_ctx *ctx)
 {
         const struct tls13_handshake_action *action;
+        int sending;
         int ret;
 
         if (!ctx->handshake_started) {
@@ -367,6 +380,13 @@ tls13_handshake_perform(struct tls13_ctx *ctx)
                 if ((action = tls13_handshake_active_action(ctx)) == NULL)
                         return TLS13_IO_FAILURE;
 
+                if (ctx->need_flush) {
+                        if ((ret = tls13_record_layer_flush(ctx->rl)) !=
+                            TLS13_IO_SUCCESS)
+                                return ret;
+                        ctx->need_flush = 0;
+                }
+
                 if (action->handshake_complete) {
                         ctx->handshake_completed = 1;
                         tls13_record_layer_handshake_completed(ctx->rl);
@@ -379,14 +399,16 @@ tls13_handshake_perform(struct tls13_ctx *ctx)
                         return TLS13_IO_SUCCESS;
                 }
 
+                sending = action->sender == ctx->mode;
+
                 DEBUGF("%s %s %s\n", tls13_handshake_mode_name(ctx->mode),
-                    (action->sender == ctx->mode) ? "sending" : "receiving",
+                    sending ? "sending" : "receiving",
                     tls13_handshake_message_name(action->handshake_type));
 
                 if (ctx->alert != 0)
                         return tls13_send_alert(ctx->rl, ctx->alert);
 
-                if (action->sender == ctx->mode)
+                if (sending)
                         ret = tls13_handshake_send_action(ctx, action);
                 else
                         ret = tls13_handshake_recv_action(ctx, action);
@@ -408,6 +430,10 @@ tls13_handshake_perform(struct tls13_ctx *ctx)
                 if (!tls13_handshake_advance_state_machine(ctx))
                         return TLS13_IO_FAILURE;
 
+                if (sending)
+                        ctx->need_flush = tls13_handshake_end_of_flight(ctx,
+                            action);
+
                 if (!tls13_handshake_set_legacy_state(ctx))
                         return TLS13_IO_FAILURE;
         }