The Tor Browser: toolkit/components/telemetry/ThirdPartyCookieProbe.jsm@129ffea94266 (annotated)

toolkit/components/telemetry/ThirdPartyCookieProbe.jsm@129ffea94266 (annotated)

toolkit/components/telemetry/ThirdPartyCookieProbe.jsm

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 let Ci = Components.interfaces;
 let Cu = Components.utils;
 let Cr = Components.results;
 Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
 Cu.import("resource://gre/modules/Services.jsm", this);
 this.EXPORTED_SYMBOLS = ["ThirdPartyCookieProbe"];
 const MILLISECONDS_PER_DAY = 1000 * 60 * 60 * 24;
 /**
  * A probe implementing the measurements detailed at
  * https://wiki.mozilla.org/SecurityEngineering/ThirdPartyCookies/Telemetry
  *
  * This implementation uses only in-memory data.
  */
 this.ThirdPartyCookieProbe = function() {
   /**
    * A set of third-party sites that have caused cookies to be
    * rejected. These sites are trimmed down to ETLD + 1
    * (i.e. "x.y.com" and "z.y.com" are both trimmed down to "y.com",
    * "x.y.co.uk" is trimmed down to "y.co.uk").
    *
    * Used to answer the following question: "For each third-party
    * site, how many other first parties embed them and result in
    * cookie traffic?" (see
    * https://wiki.mozilla.org/SecurityEngineering/ThirdPartyCookies/Telemetry#Breadth
    * )
    *
    * @type Map<string, RejectStats> A mapping from third-party site
    * to rejection statistics.
    */
   this._thirdPartyCookies = new Map();
   /**
    * Timestamp of the latest call to flush() in milliseconds since the Epoch.
    */
   this._latestFlush = Date.now();
 };
 this.ThirdPartyCookieProbe.prototype = {
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
   init: function() {
     Services.obs.addObserver(this, "profile-before-change", false);
     Services.obs.addObserver(this, "third-party-cookie-accepted", false);
     Services.obs.addObserver(this, "third-party-cookie-rejected", false);
   },
   dispose: function() {
     Services.obs.removeObserver(this, "profile-before-change");
     Services.obs.removeObserver(this, "third-party-cookie-accepted");
     Services.obs.removeObserver(this, "third-party-cookie-rejected");
   },
   /**
    * Observe either
    * - "profile-before-change" (no meaningful subject or data) - time to flush statistics and unregister; or
    * - "third-party-cookie-accepted"/"third-party-cookie-rejected" with
    *    subject: the nsIURI of the third-party that attempted to set the cookie;
    *    data: a string holding the uri of the page seen by the user.
    */
   observe: function(docURI, topic, referrer) {
     try {
       if (topic == "profile-before-change") {
         // A final flush, then unregister
         this.flush();
         this.dispose();
       }
       if (topic != "third-party-cookie-accepted"
           && topic != "third-party-cookie-rejected") {
         // Not a third-party cookie
         return;
       }
       // Add host to this._thirdPartyCookies
       // Note: nsCookieService passes "?" if the issuer is unknown.  Avoid
       //       normalizing in this case since its not a valid URI.
       let firstParty = (referrer === "?") ? referrer : normalizeHost(referrer);
       let thirdParty = normalizeHost(docURI.QueryInterface(Ci.nsIURI).host);
       let data = this._thirdPartyCookies.get(thirdParty);
       if (!data) {
         data = new RejectStats();
         this._thirdPartyCookies.set(thirdParty, data);
       }
       if (topic == "third-party-cookie-accepted") {
         data.addAccepted(firstParty);
       } else {
         data.addRejected(firstParty);
       }
     } catch (ex) {
       if (ex instanceof Ci.nsIXPCException) {
         if (ex.result == Cr.NS_ERROR_HOST_IS_IP_ADDRESS ||
             ex.result == Cr.NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS) {
           return;
         }
       }
       // Other errors should not remain silent.
       Services.console.logStringMessage("ThirdPartyCookieProbe: Uncaught error " + ex + "\n" + ex.stack);
     }
   },
   /**
    * Clear internal data, fill up corresponding histograms.
    *
    * @param {number} aNow (optional, used for testing purposes only)
    * The current instant. Used to make tests time-independent.
    */
   flush: function(aNow = Date.now()) {
     let updays = (aNow - this._latestFlush) / MILLISECONDS_PER_DAY;
     if (updays <= 0) {
       // Unlikely, but regardless, don't risk division by zero
       // or weird stuff.
       return;
     }
     this._latestFlush = aNow;
     let acceptedSites = Services.telemetry.getHistogramById("COOKIES_3RDPARTY_NUM_SITES_ACCEPTED");
     let rejectedSites = Services.telemetry.getHistogramById("COOKIES_3RDPARTY_NUM_SITES_BLOCKED");
     let acceptedRequests = Services.telemetry.getHistogramById("COOKIES_3RDPARTY_NUM_ATTEMPTS_ACCEPTED");
     let rejectedRequests = Services.telemetry.getHistogramById("COOKIES_3RDPARTY_NUM_ATTEMPTS_BLOCKED");
     for (let [k, data] of this._thirdPartyCookies) {
       acceptedSites.add(data.countAcceptedSites / updays);
       rejectedSites.add(data.countRejectedSites / updays);
       acceptedRequests.add(data.countAcceptedRequests / updays);
       rejectedRequests.add(data.countRejectedRequests / updays);
     }
     this._thirdPartyCookies.clear();
   }
 };
 /**
  * Data gathered on cookies that a third party site has attempted to set.
  *
  * Privacy note: the only data actually sent to the server is the size of
  * the sets.
  *
  * @constructor
  */
 let RejectStats = function() {
   /**
    * The set of all sites for which we have accepted third-party cookies.
    */
   this._acceptedSites = new Set();
   /**
    * The set of all sites for which we have rejected third-party cookies.
    */
   this._rejectedSites = new Set();
   /**
    * Total number of attempts to set a third-party cookie that have
    * been accepted. Two accepted attempts on the same site will both
    * augment this count.
    */
   this._acceptedRequests = 0;
   /**
    * Total number of attempts to set a third-party cookie that have
    * been rejected. Two rejected attempts on the same site will both
    * augment this count.
    */
   this._rejectedRequests = 0;
 };
 RejectStats.prototype = {
   addAccepted: function(firstParty) {
     this._acceptedSites.add(firstParty);
     this._acceptedRequests++;
   },
   addRejected: function(firstParty) {
     this._rejectedSites.add(firstParty);
     this._rejectedRequests++;
   },
   get countAcceptedSites() {
     return this._acceptedSites.size;
   },
   get countRejectedSites() {
     return this._rejectedSites.size;
   },
   get countAcceptedRequests() {
     return this._acceptedRequests;
   },
   get countRejectedRequests() {
     return this._rejectedRequests;
   }
 };
 /**
  * Normalize a host to its eTLD + 1.
  */
 function normalizeHost(host) {
   return Services.eTLD.getBaseDomainFromHost(host);
 };

The Tor Browser / annotate

toolkit/components/telemetry/ThirdPartyCookieProbe.jsm@129ffea94266 (annotated)

toolkit/components/telemetry/ThirdPartyCookieProbe.jsm