Split tls13_record_layer_set_traffic_keys() into two separate functions.

This allows the read traffic key to be set independently of the write
traffic key. This will become necessary for KeyUpdate handling, however
also allows for switching to application traffic keys at more appropriate
stages of the handshake.

ok tb@

3 files changed, 23 insertions, 17 deletions

diff --git a/src/lib/libssl/tls13_client.c b/src/lib/libssl/tls13_client.c
index c8345f3a36..5353b5a3c8 100644
--- a/src/lib/libssl/tls13_client.c
+++ b/src/lib/libssl/tls13_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_client.c,v 1.8 2019/02/13 16:29:18 jsing Exp $ */
+/* $OpenBSD: tls13_client.c,v 1.9 2019/02/14 17:55:31 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -308,8 +308,10 @@ tls13_server_hello_recv(struct tls13_ctx *ctx)
         tls13_record_layer_set_aead(ctx->rl, ctx->aead);
         tls13_record_layer_set_hash(ctx->rl, ctx->hash);
 
-        if (!tls13_record_layer_set_traffic_keys(ctx->rl,
-            &secrets->server_handshake_traffic,
+        if (!tls13_record_layer_set_read_traffic_key(ctx->rl,
+            &secrets->server_handshake_traffic))
+                goto err;
+        if (!tls13_record_layer_set_write_traffic_key(ctx->rl,
             &secrets->client_handshake_traffic))
                 goto err;
 
diff --git a/src/lib/libssl/tls13_internal.h b/src/lib/libssl/tls13_internal.h
index 2d23e6609b..71abb6c443 100644
--- a/src/lib/libssl/tls13_internal.h
+++ b/src/lib/libssl/tls13_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_internal.h,v 1.18 2019/02/14 17:50:07 jsing Exp $ */
+/* $OpenBSD: tls13_internal.h,v 1.19 2019/02/14 17:55:32 jsing Exp $ */
 /*
  * Copyright (c) 2018 Bob Beck <beck@openbsd.org>
  * Copyright (c) 2018 Theo Buehler <tb@openbsd.org>
@@ -114,8 +114,10 @@ void tls13_record_layer_set_aead(struct tls13_record_layer *rl,
 void tls13_record_layer_set_hash(struct tls13_record_layer *rl,
     const EVP_MD *hash);
 void tls13_record_layer_handshake_completed(struct tls13_record_layer *rl);
-int tls13_record_layer_set_traffic_keys(struct tls13_record_layer *rl,
-    struct tls13_secret *read_key, struct tls13_secret *write_key);
+int tls13_record_layer_set_read_traffic_key(struct tls13_record_layer *rl,
+    struct tls13_secret *read_key);
+int tls13_record_layer_set_write_traffic_key(struct tls13_record_layer *rl,
+    struct tls13_secret *write_key);
 
 ssize_t tls13_read_handshake_data(struct tls13_record_layer *rl, uint8_t *buf, size_t n);
 ssize_t tls13_write_handshake_data(struct tls13_record_layer *rl, const uint8_t *buf,
diff --git a/src/lib/libssl/tls13_record_layer.c b/src/lib/libssl/tls13_record_layer.c
index b70f9f174e..dbb5695d5e 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 1.1 2019/01/20 10:31:54 jsing Exp $ */
+/* $OpenBSD: tls13_record_layer.c,v 1.2 2019/02/14 17:55:32 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -260,21 +260,23 @@ tls13_record_layer_set_traffic_key(const EVP_AEAD *aead, EVP_AEAD_CTX *aead_ctx,
 }
 
 int
-tls13_record_layer_set_traffic_keys(struct tls13_record_layer *rl,
-    struct tls13_secret *read_key, struct tls13_secret *write_key)
+tls13_record_layer_set_read_traffic_key(struct tls13_record_layer *rl,
+    struct tls13_secret *read_key)
 {
         memset(rl->read_seq_num, 0, TLS13_RECORD_SEQ_NUM_LEN);
-        memset(rl->write_seq_num, 0, TLS13_RECORD_SEQ_NUM_LEN);
 
-        if (!tls13_record_layer_set_traffic_key(rl->aead, &rl->read_aead_ctx,
-            rl->hash, &rl->read_iv, &rl->read_nonce, read_key))
-                return 0;
+        return tls13_record_layer_set_traffic_key(rl->aead, &rl->read_aead_ctx,
+            rl->hash, &rl->read_iv, &rl->read_nonce, read_key);
+}
 
-        if (!tls13_record_layer_set_traffic_key(rl->aead, &rl->write_aead_ctx,
-            rl->hash, &rl->write_iv, &rl->write_nonce, write_key))
-                return 0;
+int
+tls13_record_layer_set_write_traffic_key(struct tls13_record_layer *rl,
+    struct tls13_secret *write_key)
+{
+        memset(rl->write_seq_num, 0, TLS13_RECORD_SEQ_NUM_LEN);
 
-        return 1;
+        return tls13_record_layer_set_traffic_key(rl->aead, &rl->write_aead_ctx,
+            rl->hash, &rl->write_iv, &rl->write_nonce, write_key);
 }
 
 static int