GetNetworkList() copies sa_family of ifa_addr to ifa_netmask if unset

net/base/net_util_posix.cc

 // Copyright (c) 2011 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/base/net_util.h"
 
 #include <sys/types.h>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 125 matching lines @@
     } else {
       // Skip non-IP addresses.
       continue;
     }
 
     IPEndPoint address;
     std::string name = interface->ifa_name;
     if (address.FromSockAddr(addr, addr_size)) {
       uint8 net_mask = 0;
       if (interface->ifa_netmask) {
+        // If not otherwise set, assume the same sa_family as ifa_addr.
+        if (interface->ifa_netmask->sa_family == 0) {
+          interface->ifa_netmask->sa_family = addr->sa_family;
+        }
         IPEndPoint netmask;
         if (netmask.FromSockAddr(interface->ifa_netmask, addr_size)) {
           net_mask = MaskPrefixLength(netmask.address());
         }
       }
 
       networks->push_back(
           NetworkInterface(name, if_nametoindex(name.c_str()),
                            address.address(), net_mask));
     }
   }
 
   freeifaddrs(interfaces);
 
   return true;
 #endif
 }
 
 WifiPHYLayerProtocol GetWifiPHYLayerProtocol() {
   return WIFI_PHY_LAYER_PROTOCOL_UNKNOWN;
 }
 
 }  // namespace net