[$csp4 adblockpluschrome] Issue 5241 - Add support for Content Security Policy filters

lib/csp.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 {RegExpFilter, WhitelistFilter} = require("filterClasses");
 const {extractHostFromFrame, getDecodedHostname,
        isThirdParty, stringifyURL} = require("url");
 const {checkWhitelisted} = require("whitelisting");
 const {FilterNotifier} = require("filterNotifier");
 const devtools = require("devtools");
 
 const {typeMap} = RegExpFilter;
 
 browser.webRequest.onHeadersReceived.addListener(details =>
 {
   let url = new URL(details.url);
   let urlString = stringifyURL(url);
-
-  let parentFrame = details.parentFrameId != -1 &&
-                      ext.getFrame(details.tabId, details.parentFrameId);
-  let hostname = extractHostFromFrame(parentFrame);
-  let thirdParty = false;
-  if (hostname)
-    thirdParty = isThirdParty(url, hostname);
-  else
-    hostname = getDecodedHostname(url);

[Sebastian Noack, 2018/03/16 23:52:38]

Is this micro-optimization worth it? Otherwise, this code could be simplified:

  let hostname = extractHostFromFrame(parentFrame) || getDecodedHostname(url);
  let thirdParty = isThirdParty(url, hostname);

[kzar, 2018/03/19 14:41:30]

Done.

+  let parentFrame = ext.getFrame(details.tabId, details.parentFrameId);
+  let hostname = extractHostFromFrame(parentFrame) || getDecodedHostname(url);
+  let thirdParty = isThirdParty(url, hostname);
 
   let cspMatch = defaultMatcher.matchesAny(urlString, typeMap.CSP, hostname,
                                            thirdParty, null, false);
   if (cspMatch)
   {
     let page = new ext.Page({id: details.tabId, url: details.url});
     let frame = ext.getFrame(details.tabId, details.frameId);
 
+    if (checkWhitelisted(page, frame))
+      return;
+
     // To avoid an extra matchesAny for the common case we assumed no
     // $genericblock filters applied when searching for a matching $csp filter.
     // We must now pay the price by first checking for a $genericblock filter
     // and if necessary that our $csp filter is specific.
-    let specificOnly = checkWhitelisted(page, frame, typeMap.GENERICBLOCK);
+    let specificOnly = !!checkWhitelisted(page, frame, typeMap.GENERICBLOCK);
     if (specificOnly)
     {
       cspMatch = defaultMatcher.matchesAny(urlString, typeMap.CSP, hostname,
                                            thirdParty, null, specificOnly);
       if (!cspMatch)
         return;
     }
 
     devtools.logRequest(page, urlString, "CSP", hostname, thirdParty, null,
                         specificOnly, cspMatch);
+    FilterNotifier.emit("filter.hitCount", cspMatch, 0, 0, page);
 
-    if (checkWhitelisted(page, frame))

[Sebastian Noack, 2018/03/16 23:52:39]

Why not doing this check earlier?

[kzar, 2018/03/19 14:41:30]

Done.

+    if (cspMatch instanceof WhitelistFilter)
       return;
-
-    FilterNotifier.emit("filter.hitCount", cspMatch, 0, 0, page);
 
     details.responseHeaders.push({

[Sebastian Noack, 2018/03/16 23:52:38]

It seems this code path is reached if cspMatch is a whitelisting filter.

[kzar, 2018/03/19 14:41:30]

Done.

       name: "Content-Security-Policy",
       value: cspMatch.csp
     });
 
     return {responseHeaders: details.responseHeaders};
   }
 }, {
   urls: ["http://*/*", "https://*/*"],
   types: ["main_frame", "sub_frame"]
 }, ["blocking", "responseHeaders"]);