Fix "IsLoopbackIp" to cover all loopback addresses; not just 127.0.0.1.

webrtc/p2p/base/turnport_unittest.cc

 /*
  *  Copyright 2012 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #if defined(WEBRTC_POSIX)
@@ skipping 434 matching lines @@
   // A certain security exploit works by redirecting to a loopback address,
   // which doesn't ever actually make sense. So redirects to loopback should
   // be treated as errors.
   // See: https://bugs.chromium.org/p/chromium/issues/detail?id=649118
   void TestTurnAlternateServerLoopback(ProtocolType protocol_type, bool ipv6) {
     const SocketAddress& local_address = ipv6 ? kLocalIPv6Addr : kLocalAddr1;
     const SocketAddress& server_address =
         ipv6 ? kTurnIPv6IntAddr : kTurnIntAddr;
 
     std::vector<rtc::SocketAddress> redirect_addresses;
-    SocketAddress loopback_address(ipv6 ? "::1" : "127.0.0.1",
+    // Pick an unusual address in the 127.0.0.0/8 range to make sure more than
+    // 127.0.0.1 is covered.
+    SocketAddress loopback_address(ipv6 ? "::1" : "127.1.2.3",
                                    TURN_SERVER_PORT);
     redirect_addresses.push_back(loopback_address);
 
     // Make a socket and bind it to the local port, to make extra sure no
     // packet is sent to this address.
     std::unique_ptr<rtc::Socket> loopback_socket(ss_->CreateSocket(
         protocol_type == PROTO_UDP ? SOCK_DGRAM : SOCK_STREAM));
     ASSERT_NE(nullptr, loopback_socket.get());
     ASSERT_EQ(0, loopback_socket->Bind(loopback_address));
     if (protocol_type == PROTO_TCP) {
@@ skipping 787 matching lines @@
   EXPECT_TRUE(turn_port_->Candidates().empty());
   turn_port_.reset();
   rtc::Thread::Current()->Post(RTC_FROM_HERE, this, MSG_TESTFINISH);
   // Waiting for above message to be processed.
   ASSERT_TRUE_SIMULATED_WAIT(test_finish_, 1, fake_clock_);
   EXPECT_EQ(last_fd_count, GetFDCount());
 }
 #endif
 
 }  // namespace cricket