require auth for the customDNS page

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

scripts/pi-hole/php/customdns.php

@@ -4,7 +4,18 @@
 
     $customDNSFile = "/etc/pihole/custom.list";
 
-    switch ($_REQUEST['action'])
+    require_once('auth.php');
+
+    // Authentication checks
+    if (isset($_POST['token'])) {
+        check_cors();
+        check_csrf($_POST['token']);
+    } else {
+        log_and_die('Not allowed (login session invalid or expired, please relogin on the Pi-hole dashboard)!');
+    }
+
+
+    switch ($_POST['action'])
     {
         case 'get':     echo json_encode(echoCustomDNSEntries()); break;
         case 'add':     echo json_encode(addCustomDNSEntry());    break;
@@ -12,4 +23,6 @@
         default:
             die("Wrong action");
     }
+
+
 ?>