Shard the SSL session cache by version fallback.

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 <errno.h>
@@ skipping 385 matching lines @@
 }
 
 SSLClientSocketOpenSSL::~SSLClientSocketOpenSSL() {
   Disconnect();
 }
 
 std::string SSLClientSocketOpenSSL::GetSessionCacheKey() const {
   std::string result = host_and_port_.ToString();
   result.append("/");
   result.append(ssl_session_cache_shard_);
+
+  // Shard the session cache based on maximum protocol version. This causes
+  // fallback connections to use a separate session cache.
+  result.append("/");
+  switch (ssl_config_.version_max) {
+    case SSL_PROTOCOL_VERSION_SSL3:
+      result.append("ssl3");
+      break;
+    case SSL_PROTOCOL_VERSION_TLS1:
+      result.append("tls1");
+      break;
+    case SSL_PROTOCOL_VERSION_TLS1_1:
+      result.append("tls1.1");
+      break;
+    case SSL_PROTOCOL_VERSION_TLS1_2:
+      result.append("tls1.2");
+      break;
+    default:
+      NOTREACHED();
+  }
+
   return result;
 }
 
 bool SSLClientSocketOpenSSL::InSessionCache() const {
   SSLContext* context = SSLContext::GetInstance();
   std::string cache_key = GetSessionCacheKey();
   return context->session_cache()->SSLSessionIsInCache(cache_key);
 }
 
 void SSLClientSocketOpenSSL::SetHandshakeCompletionCallback(
@@ skipping 1608 matching lines @@
                                             ct::SCT_STATUS_LOG_UNKNOWN));
   }
 }
 
 scoped_refptr<X509Certificate>
 SSLClientSocketOpenSSL::GetUnverifiedServerCertificateChain() const {
   return server_cert_;
 }
 
 }  // namespace net