Always treat .localhost as loopback

net/dns/host_resolver_impl.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/dns/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 54 matching lines @@
 
 // Default TTL for successful resolutions with ProcTask.
 const unsigned kCacheEntryTTLSeconds = 60;
 
 // Default TTL for unsuccessful resolutions with ProcTask.
 const unsigned kNegativeCacheEntryTTLSeconds = 0;
 
 // Minimum TTL for successful resolutions with DnsTask.
 const unsigned kMinimumTTLSeconds = kCacheEntryTTLSeconds;
 
+const char kLocalhost[] = "localhost.";
+
 // We use a separate histogram name for each platform to facilitate the
 // display of error codes by their symbolic name (since each platform has
 // different mappings).
 const char kOSErrorsForGetAddrinfoHistogramName[] =
 #if defined(OS_WIN)
     "Net.OSErrorsForGetAddrinfo_Win";
 #elif defined(OS_MACOSX)
     "Net.OSErrorsForGetAddrinfo_Mac";
 #elif defined(OS_LINUX)
     "Net.OSErrorsForGetAddrinfo_Linux";
@@ skipping 1177 matching lines @@
     // The dispatcher could have started |this| in the above call to Add, which
     // could have called Schedule again. In that case |handle| will be null,
     // but |handle_| may have been set by the other nested call to Schedule.
     if (!handle.is_null()) {
       DCHECK(handle_.is_null());
       handle_ = handle;
     }
   }
 
   void AddRequest(scoped_ptr<Request> req) {
-    DCHECK_EQ(key_.hostname, req->info().hostname());
+    // .localhost queries are redirected to "localhost." to make sure
+    // that they are never sent out on the network, per RFC 6761.
+    if (IsLocalhostTLD(req->info().hostname())) {
+      DCHECK_EQ(key_.hostname, kLocalhost);
+    } else {
+      DCHECK_EQ(key_.hostname, req->info().hostname());
+    }
 
     req->set_job(this);
     priority_tracker_.Add(req->priority());
 
     req->source_net_log().AddEvent(
         NetLog::TYPE_HOST_RESOLVER_IMPL_JOB_ATTACH,
         net_log_.source().ToEventParametersCallback());
 
     net_log_.AddEvent(
         NetLog::TYPE_HOST_RESOLVER_IMPL_JOB_REQUEST_ATTACH,
@@ skipping 902 matching lines @@
             default_address_family_ != ADDRESS_FAMILY_UNSPECIFIED);
 
         effective_address_family = ADDRESS_FAMILY_IPV4;
         effective_flags |= HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
       }
     } else {
       effective_address_family = default_address_family_;
     }
   }
 
-  return Key(info.hostname(), effective_address_family, effective_flags);
+  std::string hostname = info.hostname();
+  // Redirect .localhost queries to "localhost." to make sure that they
+  // are never sent out on the network, per RFC 6761.
+  if (IsLocalhostTLD(info.hostname())) {

[Ryan Sleevi, 2015/02/27 03:21:10]

no braces around single-line conditionals in //net

(Google style says either/or, but follow local convention. //net outside of
//quic doesn't use em)

[estark, 2015/02/27 05:00:47]

Done.

+    hostname = kLocalhost;
+  }
+
+  return Key(hostname, effective_address_family, effective_flags);
 }
 
 void HostResolverImpl::AbortAllInProgressJobs() {
   // In Abort, a Request callback could spawn new Jobs with matching keys, so
   // first collect and remove all running jobs from |jobs_|.
   ScopedVector<Job> jobs_to_abort;
   for (JobMap::iterator it = jobs_.begin(); it != jobs_.end(); ) {
     Job* job = it->second;
     if (job->is_running()) {
       jobs_to_abort.push_back(job);
@@ skipping 157 matching lines @@
     dns_client_->SetConfig(dns_config);
     num_dns_failures_ = 0;
     if (dns_client_->GetConfig())
       UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
   }
 
   AbortDnsTasks();
 }
 
 }  // namespace net