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";
 
-const {defaultMatcher} = require("matcher");
-const {BlockingFilter, RegExpFilter} = require("filterClasses");
-const {getDecodedHostname} = require("url");
-const {checkWhitelisted} = require("whitelisting");
+// 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))
+{
+  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)))
+  chrome.webRequest.onHeadersReceived.addListener(details =>
   {
-    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 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"]);
+    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, 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"]);
+}