[net/dns] If the only name server is 0.0.0.0:53 assume DnsConfig is invalid.

net/dns/dns_config_service_posix.cc

Index: net/dns/dns_config_service_posix.cc
diff --git a/net/dns/dns_config_service_posix.cc b/net/dns/dns_config_service_posix.cc
index a0571912541db487d1b3ea7dd54cff33bbfce0fa..0caf2f481fe526b55fccfb021eb2d6d2cfdcf14d 100644
--- a/net/dns/dns_config_service_posix.cc
+++ b/net/dns/dns_config_service_posix.cc
@@ -13,6 +13,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_util.h"
+#include "net/dns/dns_protocol.h"
 #include "net/dns/serial_worker.h"
 
 namespace net {
@@ -189,6 +190,11 @@ bool ConvertResStateToDnsConfig(const struct __res_state& res,
 #endif
   dns_config->edns0 = res.options & RES_USE_EDNS0;
 
+  // If the only name server is 0.0.0.0:53, assume the configuration is invalid.
+  const IPEndPoint kDefaultAddress(IPAddressNumber(kIPv4AddressSize),
+                                   dns_protocol::kDefaultPort);
+  if (dns_config->nameservers.size() == 1)
+    return !(dns_config->nameservers.front() == kDefaultAddress);

[mmenke, 2012/06/11 22:38:54]

Wonder if it makes more sense to fail if any of the entries are 0.0.0.0:53 (Or
0.0.0.0:X), since then we presumably wouldn't be behaving the same as
getaddrinfo.

[szym, 2012/06/14 16:18:20]

Done.

   return true;
 }
 #endif  // !defined(OS_ANDROID)