Always treat .localhost as loopback

net/base/net_util.cc

Index: net/base/net_util.cc
diff --git a/net/base/net_util.cc b/net/base/net_util.cc
index 3b49dffb5c20d889003a09755276ddaa8e41542d..35ac9887c7e1293bd9668deff86009b8e3bb3236 100644
--- a/net/base/net_util.cc
+++ b/net/base/net_util.cc
@@ -144,6 +144,9 @@ static const int kAllowedFtpPorts[] = {
   22,   // ssh
 };
 
+static const char kLocalhostTLD[] = ".localhost";
+static const size_t kLocalhostTLDLength = arraysize(kLocalhostTLD) - 1;

[Ryan Sleevi, 2015/03/24 23:15:20]

Turns out you could move these to line 1024, since you never use this outside
this scope.

[estark, 2015/03/25 23:53:33]

Done.

+
 bool IPNumberPrefixCheck(const IPAddressNumber& ip_number,
                          const unsigned char* ip_prefix,
                          size_t prefix_length_in_bits) {
@@ -984,7 +987,8 @@ bool IsLocalhost(const std::string& host) {
   if (host == "localhost" ||
       host == "localhost.localdomain" ||
       host == "localhost6" ||
-      host == "localhost6.localdomain6")
+      host == "localhost6.localdomain6" ||
+      IsLocalhostTLD(host))
     return true;
 
   IPAddressNumber ip_number;
@@ -1014,6 +1018,21 @@ bool IsLocalhost(const std::string& host) {
   return false;
 }
 
+bool IsLocalhostTLD(const std::string& host) {
+  if (host.empty())
+    return false;
+
+  size_t host_len = host.size();
+  if (*host.rbegin() == '.')
+    --host_len;
+  if (host_len < kLocalhostTLDLength)
+    return false;
+
+  const char* host_suffix = host.data() + host_len - kLocalhostTLDLength;
+  return base::strncasecmp(host_suffix, kLocalhostTLD, kLocalhostTLDLength) ==
+         0;
+}
+
 NetworkInterface::NetworkInterface()
     : type(NetworkChangeNotifier::CONNECTION_UNKNOWN), prefix_length(0) {
 }