Move RC4 behind a fallback.

net/http/http_network_transaction.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.
 
 #include "net/http/http_network_transaction.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 88 matching lines @@
     uint16 version_after,
     NetLog::LogLevel /* log_level */) {
   base::DictionaryValue* dict = new base::DictionaryValue();
   dict->SetString("host_and_port", GetHostAndPort(*url));
   dict->SetInteger("net_error", net_error);
   dict->SetInteger("version_before", version_before);
   dict->SetInteger("version_after", version_after);
   return dict;
 }
 
+base::Value* NetLogSSLCipherFallbackCallback(const GURL* url,
+                                             int net_error,
+                                             NetLog::LogLevel /* log_level */) {
+  base::DictionaryValue* dict = new base::DictionaryValue();
+  dict->SetString("host_and_port", GetHostAndPort(*url));
+  dict->SetInteger("net_error", net_error);
+  return dict;
+}
+
 }  // namespace
 
 //-----------------------------------------------------------------------------
 
 HttpNetworkTransaction::HttpNetworkTransaction(RequestPriority priority,
                                                HttpNetworkSession* session)
     : pending_auth_target_(HttpAuth::AUTH_NONE),
       io_callback_(base::Bind(&HttpNetworkTransaction::OnIOComplete,
                               base::Unretained(this))),
       session_(session),
@@ skipping 1114 matching lines @@
 }
 
 // TODO(rch): This does not correctly handle errors when an SSL proxy is
 // being used, as all of the errors are handled as if they were generated
 // by the endpoint host, request_->url, rather than considering if they were
 // generated by the SSL proxy. http://crbug.com/69329
 int HttpNetworkTransaction::HandleSSLHandshakeError(int error) {
   DCHECK(request_);
   HandleClientAuthError(error);
 
+  // Accept deprecated cipher suites, but only on a fallback. This makes UMA
+  // reflect servers require a deprecated cipher rather than merely prefer
+  // it. This, however, has no security benefit until the ciphers are actually
+  // removed.
+  if (!server_ssl_config_.enable_deprecated_cipher_suites &&
+      (error == ERR_SSL_VERSION_OR_CIPHER_MISMATCH ||
+       error == ERR_CONNECTION_CLOSED || error == ERR_CONNECTION_RESET)) {

[davidben, 2015/04/01 22:22:59]

This matches the set of error codes Mozilla uses. fonts.com does a reset
(happened to pick one that did at random).

Both BoringSSL and NSS ports should now map a handshake_failure in response to a
ClientHello to ERR_SSL_VERSION_OR_CIPHER_MISMATCH, so there shouldn't be any
need to toss ERR_SSL_PROTOCOL_ERROR into the mix.

+    net_log_.AddEvent(
+        NetLog::TYPE_SSL_CIPHER_FALLBACK,
+        base::Bind(&NetLogSSLCipherFallbackCallback, &request_->url, error));
+    server_ssl_config_.enable_deprecated_cipher_suites = true;
+    ResetConnectionAndRequestForResend();
+    return OK;
+  }
+
   bool should_fallback = false;
   uint16 version_max = server_ssl_config_.version_max;
 
   switch (error) {
     case ERR_CONNECTION_CLOSED:
     case ERR_SSL_PROTOCOL_ERROR:
     case ERR_SSL_VERSION_OR_CIPHER_MISMATCH:
       if (version_max >= SSL_PROTOCOL_VERSION_TLS1 &&
           version_max > server_ssl_config_.version_min) {
         // This could be a TLS-intolerant server or a server that chose a
@@ skipping 276 matching lines @@
       description = base::StringPrintf("Unknown state 0x%08X (%u)", state,
                                        state);
       break;
   }
   return description;
 }
 
 #undef STATE_CASE
 
 }  // namespace net