Add code to build and send a server hello for tls 1.3

ok jsing@

1 files changed, 40 insertions, 3 deletions

diff --git a/src/lib/libssl/tls13_server.c b/src/lib/libssl/tls13_server.c
index 88935cf645..6171010772 100644
--- a/src/lib/libssl/tls13_server.c
+++ b/src/lib/libssl/tls13_server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_server.c,v 1.8 2020/01/23 02:24:38 jsing Exp $ */
+/* $OpenBSD: tls13_server.c,v 1.9 2020/01/23 06:59:11 beck Exp $ */
 /*
  * Copyright (c) 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -44,6 +44,8 @@ tls13_server_init(struct tls13_ctx *ctx)
         if (!tls1_transcript_init(s))
                 return 0;
 
+        arc4random_buf(s->s3->server_random, SSL3_RANDOM_SIZE);
+
         return 1;
 }
 
@@ -287,12 +289,47 @@ tls13_client_key_update_recv(struct tls13_ctx *ctx, CBS *cbs)
         return 0;
 }
 
+static int
+tls13_server_hello_build(struct tls13_ctx *ctx, CBB *cbb)
+{
+        CBB session_id;
+        SSL *s = ctx->ssl;
+        uint16_t cipher;
+
+        cipher = SSL_CIPHER_get_value(S3I(s)->hs.new_cipher);
+
+        if (!CBB_add_u16(cbb, TLS1_2_VERSION))
+                goto err;
+        if (!CBB_add_bytes(cbb, s->s3->server_random, SSL3_RANDOM_SIZE))
+                goto err;
+        if (!CBB_add_u8_length_prefixed(cbb, &session_id))
+                goto err;
+        if (!CBB_add_bytes(&session_id, ctx->hs->legacy_session_id,
+            ctx->hs->legacy_session_id_len))
+                goto err;
+        if (!CBB_add_u16(cbb, cipher))
+                goto err;
+        if (!CBB_add_u8(cbb, 0))
+                goto err;
+        if (!tlsext_server_build(s, cbb, SSL_TLSEXT_MSG_SH))
+                goto err;
+
+        if (!CBB_flush(cbb))
+                goto err;
+
+        return 1;
+err:
+        return 0;
+}
+
 int
 tls13_server_hello_send(struct tls13_ctx *ctx, CBB *cbb)
 {
-        ctx->handshake_stage.hs_type |= NEGOTIATED;
+        if (!tls13_server_hello_build(ctx, cbb))
+                return 0;
 
-        return 0;
+        ctx->handshake_stage.hs_type |= NEGOTIATED;
+        return 1;
 }
 
 int