Split the tls12_record_layer_write_mac() function.

Split the existing tls12_record_layer_write_mac() function so that we can
soon reuse part of it for the read side.

No functional change.

ok tb@

1 files changed, 19 insertions, 10 deletions

diff --git a/src/lib/libssl/tls12_record_layer.c b/src/lib/libssl/tls12_record_layer.c
index d1686cb5bd..1984e177bd 100644
--- a/src/lib/libssl/tls12_record_layer.c
+++ b/src/lib/libssl/tls12_record_layer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls12_record_layer.c,v 1.2 2020/09/15 15:11:58 jsing Exp $ */
+/* $OpenBSD: tls12_record_layer.c,v 1.3 2020/09/15 16:07:17 jsing Exp $ */
 /*
  * Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
  *
@@ -227,9 +227,10 @@ tls12_record_layer_pseudo_header(struct tls12_record_layer *rl,
 }
 
 static int
-tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
-    uint8_t content_type, const uint8_t *content, size_t content_len,
-    size_t *out_len)
+tls12_record_layer_mac(struct tls12_record_layer *rl, CBB *cbb,
+    EVP_MD_CTX *hash_ctx, int stream_mac, uint16_t epoch, uint8_t *seq_num,
+    size_t seq_num_len, uint8_t content_type, const uint8_t *content,
+    size_t content_len, size_t *out_len)
 {
         EVP_MD_CTX *mac_ctx = NULL;
         uint8_t *header = NULL;
@@ -240,12 +241,11 @@ tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
 
         if ((mac_ctx = EVP_MD_CTX_new()) == NULL)
                 goto err;
-        if (!EVP_MD_CTX_copy(mac_ctx, rl->write_hash_ctx))
+        if (!EVP_MD_CTX_copy(mac_ctx, hash_ctx))
                 goto err;
 
         if (!tls12_record_layer_pseudo_header(rl, content_type, content_len,
-            rl->write_epoch, rl->write_seq_num, SSL3_SEQUENCE_SIZE,
-            &header, &header_len))
+            epoch, seq_num, seq_num_len, &header, &header_len))
                 goto err;
 
         if (EVP_DigestSignUpdate(mac_ctx, header, header_len) <= 0)
@@ -259,13 +259,12 @@ tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
         if (EVP_DigestSignFinal(mac_ctx, mac, &mac_len) <= 0)
                 goto err;
 
-        if (rl->write_stream_mac) {
-                if (!EVP_MD_CTX_copy(rl->write_hash_ctx, mac_ctx))
+        if (stream_mac) {
+                if (!EVP_MD_CTX_copy(hash_ctx, mac_ctx))
                         goto err;
         }
 
         *out_len = mac_len;
-
         ret = 1;
 
  err:
@@ -276,6 +275,16 @@ tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
 }
 
 static int
+tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
+    uint8_t content_type, const uint8_t *content, size_t content_len,
+    size_t *out_len)
+{
+        return tls12_record_layer_mac(rl, cbb, rl->write_hash_ctx,
+            rl->write_stream_mac, rl->write_epoch, rl->write_seq_num,
+            SSL3_SEQUENCE_SIZE, content_type, content, content_len, out_len);
+}
+
+static int
 tls12_record_layer_seal_record_plaintext(struct tls12_record_layer *rl,
     uint8_t content_type, const uint8_t *content, size_t content_len, CBB *out)
 {