Refuse to resolve some types of invalid DNS addresses.

net/dns/dns_hosts.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/dns_hosts.h"
 
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
+#include "net/dns/dns_util.h"
 
 using base::StringPiece;
 
 namespace net {
 
 namespace {
 
 // Parses the contents of a hosts file.  Returns one token (IP or hostname) at
 // a time.  Doesn't copy anything; accepts the file as a StringPiece and
 // returns tokens as StringPieces.
@@ skipping 126 matching lines @@
         if (new_ip.AssignFromIPLiteral(parser.token())) {
           ip_text = new_ip_text;
           ip = new_ip;
           family = (ip.IsIPv4()) ? ADDRESS_FAMILY_IPV4 : ADDRESS_FAMILY_IPV6;
         } else {
           parser.SkipRestOfLine();
         }
       }
     } else {
       DnsHostsKey key(parser.token().as_string(), family);
+      if (!IsValidDNSDomain(key.first))
+        continue;
       key.first = base::ToLowerASCII(key.first);
       IPAddress* mapped_ip = &(*dns_hosts)[key];
       if (mapped_ip->empty())
         *mapped_ip = ip;
       // else ignore this entry (first hit counts)
     }
   }
 }
 
 }  // namespace
@@ skipping 38 matching lines @@
   std::string contents;
   if (!base::ReadFileToString(path, &contents))
     return false;
 
   ParseHosts(contents, dns_hosts);
   return true;
 }
 
 }  // namespace net