Require ECDHE cipher in remoting client.

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 747 matching lines @@
 
   // Removing ciphers by ID from OpenSSL is a bit involved as we must use the
   // textual name with SSL_set_cipher_list because there is no public API to
   // directly remove a cipher by ID.
   STACK_OF(SSL_CIPHER)* ciphers = SSL_get_ciphers(ssl_);
   DCHECK(ciphers);
   // See SSLConfig::disabled_cipher_suites for description of the suites
   // disabled by default. Note that !SHA256 and !SHA384 only remove HMAC-SHA256
   // and HMAC-SHA384 cipher suites, not GCM cipher suites with SHA256 or SHA384
   // as the handshake hash.
-  std::string command(
-      "DEFAULT:!NULL:!aNULL:!SHA256:!SHA384:!aECDH:!AESGCM+AES256:!aPSK");
+  std::string command("DEFAULT:!SHA256:!SHA384:!AESGCM+AES256:!aPSK");
   // Walk through all the installed ciphers, seeing if any need to be
   // appended to the cipher removal |command|.
   for (size_t i = 0; i < sk_SSL_CIPHER_num(ciphers); ++i) {
     const SSL_CIPHER* cipher = sk_SSL_CIPHER_value(ciphers, i);
     const uint16 id = static_cast<uint16>(SSL_CIPHER_get_id(cipher));
-    // Remove any ciphers with a strength of less than 80 bits. Note the NSS
-    // implementation uses "effective" bits here but OpenSSL does not provide
-    // this detail. This only impacts Triple DES: reports 112 vs. 168 bits,
-    // both of which are greater than 80 anyway.
-    bool disable = SSL_CIPHER_get_bits(cipher, NULL) < 80;
+    bool disable = false;
+    if (ssl_config_.require_ecdhe) {
+      base::StringPiece kx_name(SSL_CIPHER_get_kx_name(cipher));
+      disable = kx_name != "ECDHE_RSA" && kx_name != "ECDHE_ECDSA";
+    }
     if (!disable) {
       disable = std::find(ssl_config_.disabled_cipher_suites.begin(),
                           ssl_config_.disabled_cipher_suites.end(), id) !=
                     ssl_config_.disabled_cipher_suites.end();
     }
     if (disable) {
        const char* name = SSL_CIPHER_get_name(cipher);
        DVLOG(3) << "Found cipher to remove: '" << name << "', ID: " << id
                 << " strength: " << SSL_CIPHER_get_bits(cipher, NULL);
        command.append(":!");
@@ skipping 1127 matching lines @@
 
   NextProto next_proto = NextProtoFromString(npn_proto_);
   for (NextProto allowed : ssl_config_.renego_allowed_for_protos) {
     if (next_proto == allowed)
       return true;
   }
   return false;
 }
 
 }  // namespace net