sanitize scope and host

apps/remoteStorage/auth.php

@@ -44,9 +44,9 @@ foreach($_GET as $k => $v) {
     $userId=$v;
   } else if($k=='redirect_uri'){
     $appUrlParts=explode('/', $v);
-    $appUrl = $appUrlParts[2];//bit dodgy i guess
+    $appUrl = htmlentities($appUrlParts[2]);//TODO: check if this is equal to client_id
   } else if($k=='scope'){
-    $categories=$v;
+    $categories=htmlentities($v);
   }
 }
 $currUser = OCP\USER::getUser();