[enhancement] 0.0.0.0/0 IP Masks always match if they receive a valid IP as input

Author: sscarduzio

src/main/java/org/elasticsearch/plugin/readonlyrest/acl/blocks/rules/IPMask.java

@@ -86,6 +86,10 @@ private static int addrToInt(Inet4Address i4addr) {
    */
   public boolean matches(Inet4Address testAddr) {
     int testAddrInt = addrToInt(testAddr);
+    // Always allow 0.0.0.0/0 as a wild card
+    if (maskInt == -1 && addrInt == 0) {
+      return true;
+    }
     return (addrInt & maskInt) == (testAddrInt & maskInt);
   }