Remove the free_buffer parameter to release_current_message.

With on_handshake_complete, this can be managed internally by the TLS
code. The next commit will add a ton more calls to this function.

Change-Id: I91575d3e4bfcccbbe492017ae33c74b8cc1d1340
Reviewed-on: https://boringssl-review.googlesource.com/18865
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>

ssl/d1_both.cc

@@ -425,7 +425,7 @@ int dtls1_get_message(SSL *ssl) {
     assert(ssl->init_msg != NULL);
     ssl->s3->tmp.reuse_message = 0;
   } else {
-    dtls1_release_current_message(ssl, 0 /* don't free buffer */);
+    dtls1_release_current_message(ssl);
   }
 
   /* Process handshake records until the current message is ready. */
@@ -463,7 +463,7 @@ void dtls1_get_current_message(const SSL *ssl, CBS *out) {
   CBS_init(out, frag->data, DTLS1_HM_HEADER_LENGTH + frag->msg_len);
 }
 
-void dtls1_release_current_message(SSL *ssl, int free_buffer) {
+void dtls1_release_current_message(SSL *ssl) {
   if (ssl->init_msg == NULL) {
     return;
   }

ssl/dtls_method.cc

@@ -73,6 +73,7 @@ static int dtls1_supports_cipher(const SSL_CIPHER *cipher) {
 }
 
 static void dtls1_on_handshake_complete(SSL *ssl) {
+  dtls1_release_current_message(ssl);
   /* If we wrote the last flight, we'll have a timer left over without waiting
    * for a read. Stop the timer but leave the flight around for post-handshake
    * transmission logic. */

ssl/handshake_client.cc

@@ -492,7 +492,6 @@ int ssl3_connect(SSL_HANDSHAKE *hs) {
 
       case SSL3_ST_FINISH_CLIENT_HANDSHAKE:
         ssl->method->on_handshake_complete(ssl);
-        ssl->method->release_current_message(ssl, 1 /* free_buffer */);
 
         SSL_SESSION_free(ssl->s3->established_session);
         if (ssl->session != NULL) {

ssl/handshake_server.cc

@@ -418,7 +418,6 @@ int ssl3_accept(SSL_HANDSHAKE *hs) {
 
       case SSL_ST_OK:
         ssl->method->on_handshake_complete(ssl);
-        ssl->method->release_current_message(ssl, 1 /* free_buffer */);
 
         /* If we aren't retaining peer certificates then we can discard it
          * now. */

ssl/internal.h

@@ -2137,7 +2137,7 @@ int ssl3_get_finished(SSL_HANDSHAKE *hs);
 int ssl3_send_alert(SSL *ssl, int level, int desc);
 int ssl3_get_message(SSL *ssl);
 void ssl3_get_current_message(const SSL *ssl, CBS *out);
-void ssl3_release_current_message(SSL *ssl, int free_buffer);
+void ssl3_release_current_message(SSL *ssl);
 
 int ssl3_send_finished(SSL_HANDSHAKE *hs);
 int ssl3_dispatch_alert(SSL *ssl);
@@ -2216,7 +2216,7 @@ void dtls1_free(SSL *ssl);
 
 int dtls1_get_message(SSL *ssl);
 void dtls1_get_current_message(const SSL *ssl, CBS *out);
-void dtls1_release_current_message(SSL *ssl, int free_buffer);
+void dtls1_release_current_message(SSL *ssl);
 int dtls1_dispatch_alert(SSL *ssl);
 
 int tls1_change_cipher_state(SSL_HANDSHAKE *hs, int which);
@@ -2362,9 +2362,9 @@ struct ssl_protocol_method_st {
   /* get_current_message sets |*out| to the current handshake message. This
    * includes the protocol-specific message header. */
   void (*get_current_message)(const SSL *ssl, CBS *out);
-  /* release_current_message is called to release the current handshake message.
-   * If |free_buffer| is one, buffers will also be released. */
-  void (*release_current_message)(SSL *ssl, int free_buffer);
+  /* release_current_message is called to release the current handshake
+   * message. */
+  void (*release_current_message)(SSL *ssl);
   /* read_app_data reads up to |len| bytes of application data into |buf|. On
    * success, it returns the number of bytes read. Otherwise, it returns <= 0
    * and sets |*out_got_handshake| to whether the failure was due to a

ssl/s3_both.cc

@@ -683,6 +683,14 @@ static int read_v2_client_hello(SSL *ssl) {
 }
 
 int ssl3_get_message(SSL *ssl) {
+  if (ssl->s3->tmp.reuse_message) {
+    /* There must be a current message. */
+    assert(ssl->init_msg != NULL);
+    ssl->s3->tmp.reuse_message = 0;
+  } else {
+    ssl3_release_current_message(ssl);
+  }
+
   /* Re-create the handshake buffer if needed. */
   if (ssl->init_buf == NULL) {
     ssl->init_buf = BUF_MEM_new();
@@ -700,14 +708,6 @@ int ssl3_get_message(SSL *ssl) {
     ssl->s3->v2_hello_done = 1;
   }
 
-  if (ssl->s3->tmp.reuse_message) {
-    /* There must be a current message. */
-    assert(ssl->init_msg != NULL);
-    ssl->s3->tmp.reuse_message = 0;
-  } else {
-    ssl3_release_current_message(ssl, 0 /* don't free buffer */);
-  }
-
   /* Read the message header, if we haven't yet. */
   int ret = extend_handshake_buffer(ssl, SSL3_HM_HEADER_LENGTH);
   if (ret <= 0) {
@@ -757,19 +757,23 @@ int ssl_hash_current_message(SSL_HANDSHAKE *hs) {
   return hs->transcript.Update(CBS_data(&cbs), CBS_len(&cbs));
 }
 
-void ssl3_release_current_message(SSL *ssl, int free_buffer) {
-  if (ssl->init_msg != NULL) {
-    /* |init_buf| never contains data beyond the current message. */
-    assert(SSL3_HM_HEADER_LENGTH + ssl->init_num == ssl->init_buf->length);
-
-    /* Clear the current message. */
-    ssl->init_msg = NULL;
-    ssl->init_num = 0;
-    ssl->init_buf->length = 0;
-    ssl->s3->is_v2_hello = 0;
+void ssl3_release_current_message(SSL *ssl) {
+  if (ssl->init_msg == NULL) {
+    return;
   }
 
-  if (free_buffer) {
+  /* |init_buf| never contains data beyond the current message. */
+  assert(SSL3_HM_HEADER_LENGTH + ssl->init_num == ssl->init_buf->length);
+
+  /* Clear the current message. */
+  ssl->init_msg = NULL;
+  ssl->init_num = 0;
+  ssl->init_buf->length = 0;
+  ssl->s3->is_v2_hello = 0;
+
+  /* Post-handshake messages are rare, so release the buffer after every
+   * message. During the handshake, |on_handshake_complete| will release it. */
+  if (!SSL_in_init(ssl)) {
     BUF_MEM_free(ssl->init_buf);
     ssl->init_buf = NULL;
   }

ssl/s3_pkt.cc

@@ -377,7 +377,7 @@ int ssl3_read_app_data(SSL *ssl, int *out_got_handshake, uint8_t *buf, int len,
   assert(!ssl->s3->aead_read_ctx->is_null_cipher());
   *out_got_handshake = 0;
 
-  ssl->method->release_current_message(ssl, 0 /* don't free buffer */);
+  ssl->method->release_current_message(ssl);
 
   SSL3_RECORD *rr = &ssl->s3->rrec;
 

ssl/ssl_lib.cc

@@ -942,7 +942,7 @@ static int ssl_read_impl(SSL *ssl, void *buf, int num, int peek) {
     if (!ssl_do_post_handshake(ssl)) {
       return -1;
     }
-    ssl->method->release_current_message(ssl, 1 /* free buffer */);
+    ssl->method->release_current_message(ssl);
   }
 }
 

ssl/tls_method.cc

@@ -69,7 +69,11 @@ namespace bssl {
 
 static int ssl3_supports_cipher(const SSL_CIPHER *cipher) { return 1; }
 
-static void ssl3_on_handshake_complete(SSL *ssl) {}
+static void ssl3_on_handshake_complete(SSL *ssl) {
+  ssl3_release_current_message(ssl);
+  BUF_MEM_free(ssl->init_buf);
+  ssl->init_buf = NULL;
+}
 
 static int ssl3_set_read_state(SSL *ssl, UniquePtr<SSLAEADContext> aead_ctx) {
   if (ssl->s3->rrec.length != 0) {