Issue 3163 - Adapt "Block element" functionality for a change in Chrome dealing with "\0" in CSS se…

lib/filterComposer.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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/>.
  */
 
 /** @module filterComposer */
 
 let {extractHostFromFrame, stringifyURL, isThirdParty} = require("url");
 let {getKey, isFrameWhitelisted} = require("whitelisting");
 let {defaultMatcher} = require("matcher");
 let {RegExpFilter} = require("filterClasses");
 
+function isValidString(s) {
+  return s && s.indexOf("\0") == -1;
+}
+
 function escapeChar(chr)
 {
   let code = chr.charCodeAt(0);
 
   // Control characters and leading digits must be escaped based on
   // their char code in CSS. Moreover, curly brackets aren't allowed
   // in elemhide filters, and therefore must be escaped based on their
   // char code as well.
   if (code <= 0x1F || code == 0x7F || /[\d\{\}]/.test(chr))
     return "\\" + code.toString(16) + " ";
@@ skipping 77 matching lines @@
         if (filters.indexOf(filterText) == -1)
           filters.push(filterText);
       }
     }
 
     // If we couldn't generate any blocking filters, fallback to element hiding
     let selectors = [];
     if (filters.length == 0 && !isFrameWhitelisted(page, frame, RegExpFilter.typeMap.ELEMHIDE))
     {
       // Generate CSS selectors based on the element's "id" and "class" attribute
-      if (details.id)
+      if (isValidString(details.id))
         selectors.push("#" + escapeCSS(details.id));
-      if (details.classes.length > 0)
-        selectors.push(details.classes.map(c => "." + escapeCSS(c)).join(""));
+
+      let classes = details.classes.filter(isValidString);
+      if (classes.length > 0)
+        selectors.push(classes.map(c => "." + escapeCSS(c)).join(""));
 
       // If there is a "src" attribute, specifiying a URL that we can't block,
       // generate a CSS selector matching the "src" attribute
-      if (details.src)
+      if (isValidString(details.src))
         selectors.push(escapeCSS(details.tagName) + "[src=" + quoteCSS(details.src) + "]");
 
       // As last resort, if there is a "style" attribute, and we couldn't generate
       // any filters so far, generate a CSS selector matching the "style" attribute
-      if (details.style && selectors.length == 0 && filters.length == 0)
+      if (isValidString(details.style) && selectors.length == 0 && filters.length == 0)
         selectors.push(escapeCSS(details.tagName) + "[style=" + quoteCSS(details.style) + "]");
 
       // Add an element hiding filter for each generated CSS selector
       for (let selector of selectors)
         filters.push(docDomain.replace(/^www\./, "") + "##" + selector);
     }
   }
 
   return {filters: filters, selectors: selectors};
 };