Issue 491 - Validate custom filters

background.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 with(require("filterClasses"))
 {
   this.Filter = Filter;
   this.RegExpFilter = RegExpFilter;
   this.BlockingFilter = BlockingFilter;
   this.WhitelistFilter = WhitelistFilter;
+  this.InvalidFilter = InvalidFilter;
 }
 with(require("subscriptionClasses"))
 {
   this.Subscription = Subscription;
   this.DownloadableSubscription = DownloadableSubscription;
   this.SpecialSubscription = SpecialSubscription;
 }
 with(require("whitelisting"))
 {
   this.isWhitelisted = isWhitelisted;
@@ skipping 483 matching lines @@
     case "get-domain-enabled-state":
       // Returns whether this domain is in the exclusion list.
       // The browser action popup asks us this.
       if(sender.page)
       {
         sendResponse({enabled: !isWhitelisted(sender.page.url)});
         return;
       }
       break;
     case "add-filters":
-      if (msg.filters && msg.filters.length)
+      var filters = [];
+

[kzar, 2014/11/18 16:32:10]

How come you don't check that msg.filters and msg.filters.length are truthy here
any more?

[Sebastian Noack, 2014/11/18 17:42:55]

There was no point in checking it in the first place, since this message is
always send with an array, and whether it is empty or not doesn't matter.

+      for (var i = 0; i < msg.filters.length; i++)
       {
-        for (var i = 0; i < msg.filters.length; i++)
-          FilterStorage.addFilter(Filter.fromText(msg.filters[i]));
+        var filter = Filter.fromText(msg.filters[i], true);

[kzar, 2014/11/18 16:32:10]

Instead of having this separate filter variable how about pushing the filter
onto the filters array straight away? Then you could check if filters[i] was an
instance of InvalidFilter before proceeding.

[Sebastian Noack, 2014/11/18 17:42:55]

We have to access the filter object 3 times (or 2 times if directly pushed to
the array). So accessing that object via an array index, is neither more
readable nor efficient.

+        if (filter instanceof InvalidFilter)
+        {
+          sendResponse({status: "invalid", error: filter.reason});
+          return;
+        }
+        filters.push(filter);
       }
+
+      for (var i = 0; i < filters.length; i++)

[kzar, 2014/11/18 16:32:10]

You've re-declared the `i` variable here.

+        FilterStorage.addFilter(filters[i]);
+
+      sendResponse({status: "ok"});
       break;
     case "add-subscription":
       ext.showOptions(function(page)
       {
         page.sendMessage(msg);
       });
       break;
     case "add-sitekey":
       processKey(msg.token, sender.page, sender.frame);
       break;
@@ skipping 22 matching lines @@
   page.sendMessage({type: "clickhide-deactivate"});
   refreshIconAndContextMenu(page);
 });
 
 setTimeout(function()
 {
   var notificationToShow = Notification.getNextToShow();
   if (notificationToShow)
     showNotification(notificationToShow);
 }, 3 * 60 * 1000);