net: disable TLS compression with OpenSSL.

net/socket/ssl_client_socket_openssl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // OpenSSL binding for SSLClientSocket. The class layout and general principle
 // of operation is derived from SSLClientSocketNSS.
 
 #include "net/socket/ssl_client_socket_openssl.h"
 
 #include <openssl/ssl.h>
@@ skipping 472 matching lines @@
   options.ConfigureFlag(SSL_OP_NO_TLSv1_1, !tls1_1_enabled);
 #endif
 #if defined(SSL_OP_NO_TLSv1_2)
   bool tls1_2_enabled =
       (ssl_config_.version_min <= SSL_PROTOCOL_VERSION_TLS1_2 &&
        ssl_config_.version_max >= SSL_PROTOCOL_VERSION_TLS1_2);
   options.ConfigureFlag(SSL_OP_NO_TLSv1_2, !tls1_2_enabled);
 #endif
 
 #if defined(SSL_OP_NO_COMPRESSION)
-  // If TLS was disabled also disable compression, to provide maximum site
-  // compatibility in the case of protocol fallback. See http://crbug.com/31628
-  options.ConfigureFlag(SSL_OP_NO_COMPRESSION,
-                        ssl_config_.version_max < SSL_PROTOCOL_VERSION_TLS1);
+  options.ConfigureFlag(SSL_OP_NO_COMPRESSION, true);
 #endif
 
   // TODO(joth): Set this conditionally, see http://crbug.com/55410
   options.ConfigureFlag(SSL_OP_LEGACY_SERVER_CONNECT, true);
 
   SSL_set_options(ssl_, options.set_mask);
   SSL_clear_options(ssl_, options.clear_mask);
 
   // Same as above, this time for the SSL mode.
   SslSetClearMask mode;
@@ skipping 814 matching lines @@
     net_log_.AddByteTransferEvent(NetLog::TYPE_SSL_SOCKET_BYTES_SENT, rv,
                                   user_write_buf_->data());
     return rv;
   }
 
   int err = SSL_get_error(ssl_, rv);
   return MapOpenSSLError(err, err_tracer);
 }
 
 }  // namespace net