Issue 5027 - Use updated webRequest API for WebSocket blocking

lib/csp.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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/>.
  */
 
 "use strict";
 
+// Before Chrome 58, the webRequest API did not intercept WebSocket
+// connections (see https://crbug.com/129353). Hence we inject CSP headers,
+// below, as a workaround.
 if (!("WEBSOCKET" in chrome.webRequest.ResourceType))

[Jon Sonesen, 2017/03/27 11:58:57]

I am not sure whether the imports should be in or out of this statement and do
not really have an opinion.

 {
   const {defaultMatcher} = require("matcher");
   const {BlockingFilter, RegExpFilter} = require("filterClasses");
   const {getDecodedHostname} = require("url");
   const {checkWhitelisted} = require("whitelisting");
 
   chrome.webRequest.onHeadersReceived.addListener(details =>
   {
     let hostname = getDecodedHostname(new URL(details.url));
     let match = defaultMatcher.matchesAny("", RegExpFilter.typeMap.WEBSOCKET,
                                           hostname, false, null, true);
     if (match instanceof BlockingFilter &&
         !checkWhitelisted(new ext.Page({id: details.tabId}),
                           ext.getFrame(details.tabId, details.frameId)))
     {
       details.responseHeaders.push({
         name: "Content-Security-Policy",
         // We're blocking WebSockets here by adding a connect-src restriction
         // since the Chrome extension API does not allow us to intercept them.
         // https://bugs.chromium.org/p/chromium/issues/detail?id=129353
         //
-        // We also need the frame-src and object-src restrictions since CSPs are
-        // not inherited from the parent for documents with data: and blob: URLs.
-        // https://bugs.chromium.org/p/chromium/issues/detail?id=513860
+        // We also need the frame-src and object-src restrictions since CSPs
+        // are not inherited from the parent for documents with data: and blob:
+        // URLs, see https://crbug.com/513860.
         //
         // We must use the deprecated child-src directive instead of worker-src
         // since that's not supported yet (as of Chrome 56.)
         //
         // "http:" also includes "https:" implictly.
         // https://www.chromestatus.com/feature/6653486812889088
         value: "connect-src http:; child-src http:; frame-src http:; object-src http:"
       });
       return {responseHeaders: details.responseHeaders};
     }
   }, {
     urls: ["http://*/*", "https://*/*"],
     // We must also intercept script requests since otherwise Web Workers can
     // be abused to execute scripts for which our Content Security Policy
     // won't be injected.
     // https://github.com/gorhill/uBO-Extra/issues/19
     types: ["main_frame", "sub_frame", "script"]
   }, ["blocking", "responseHeaders"]);
 }