commit 8f820b4e439ee9f255ff93d94e0879fa798a6b2d
author David Benjamin <davidben@google.com> Wed Nov 30 11:24:40 2016 -0500
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Thu Dec 01 19:26:14 2016 +0000
tree e10b177746a70c5c92db21e2ec8b08f50ab1c0f0
parent ce1f62c3beba48d627698ba41695479eeb0d894c

Clean up resumption secret "derivation" step.

There is no more derivation step. We just use the resumption secret
directly. This saves us an unnecessary memcpy.

Change-Id: I203bdcc0463780c47cce655046aa1be560bb5b18
Reviewed-on: https://boringssl-review.googlesource.com/12472
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

ssl/tls13_client.c

diff --git a/ssl/tls13_client.c b/ssl/tls13_client.c
index 4a30ce3..5a1a90d 100644
--- a/ssl/tls13_client.c
+++ b/ssl/tls13_client.c
@@ -48,6 +48,8 @@
   state_done,
 };
 
+static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
+
 static enum ssl_hs_wait_t do_process_hello_retry_request(SSL *ssl,
                                                          SSL_HANDSHAKE *hs) {
   if (ssl->s3->tmp.message_type != SSL3_MT_HELLO_RETRY_REQUEST) {
@@ -275,20 +277,17 @@
   /* The PRF hash is now known. Set up the key schedule. */
   size_t hash_len =
       EVP_MD_size(ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl)));
-
-  /* Derive resumption material. */
-  uint8_t psk_secret[EVP_MAX_MD_SIZE] = {0};
-  if (ssl->s3->session_reused) {
-    if (hash_len != (size_t) ssl->s3->new_session->master_key_length) {
-      return ssl_hs_error;
-    }
-    memcpy(psk_secret, ssl->s3->new_session->master_key, hash_len);
+  if (!tls13_init_key_schedule(ssl)) {
+    return ssl_hs_error;
   }
 
-  /* Set up the key schedule, hash in the ClientHello, and incorporate the PSK
-   * into the running secret. */
-  if (!tls13_init_key_schedule(ssl) ||
-      !tls13_advance_key_schedule(ssl, psk_secret, hash_len)) {
+  /* Incorporate the PSK into the running secret. */
+  if (ssl->s3->session_reused) {
+    if (!tls13_advance_key_schedule(ssl, ssl->s3->new_session->master_key,
+                                    ssl->s3->new_session->master_key_length)) {
+      return ssl_hs_error;
+    }
+  } else if (!tls13_advance_key_schedule(ssl, kZeroes, hash_len)) {
     return ssl_hs_error;
   }
 
@@ -430,7 +429,6 @@
 
 static enum ssl_hs_wait_t do_process_server_finished(SSL *ssl,
                                                      SSL_HANDSHAKE *hs) {
-  static const uint8_t kZeroes[EVP_MAX_MD_SIZE] = {0};
   if (!tls13_check_message_type(ssl, SSL3_MT_FINISHED) ||
       !tls13_process_finished(ssl) ||
       !ssl_hash_current_message(ssl) ||

ssl/tls13_server.c

diff --git a/ssl/tls13_server.c b/ssl/tls13_server.c
index 83ef679..e10e88e 100644
--- a/ssl/tls13_server.c
+++ b/ssl/tls13_server.c
@@ -284,23 +284,20 @@
     return ssl_hs_error;
   }
 
-  /* The PRF hash is now known. */
+  /* The PRF hash is now known. Set up the key schedule. */
   size_t hash_len =
       EVP_MD_size(ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl)));
-
-  /* Derive resumption material. */
-  uint8_t psk_secret[EVP_MAX_MD_SIZE] = {0};
-  if (ssl->s3->session_reused) {
-    if (hash_len != (size_t) ssl->s3->new_session->master_key_length) {
-      return ssl_hs_error;
-    }
-    memcpy(psk_secret, ssl->s3->new_session->master_key, hash_len);
+  if (!tls13_init_key_schedule(ssl)) {
+    return ssl_hs_error;
   }
 
-  /* Set up the key schedule, hash in the ClientHello, and incorporate the PSK
-   * into the running secret. */
-  if (!tls13_init_key_schedule(ssl) ||
-      !tls13_advance_key_schedule(ssl, psk_secret, hash_len)) {
+  /* Incorporate the PSK into the running secret. */
+  if (ssl->s3->session_reused) {
+    if (!tls13_advance_key_schedule(ssl, ssl->s3->new_session->master_key,
+                                    ssl->s3->new_session->master_key_length)) {
+      return ssl_hs_error;
+    }
+  } else if (!tls13_advance_key_schedule(ssl, kZeroes, hash_len)) {
     return ssl_hs_error;
   }