[tor-bugs] #13027 [Tor Browser]: Make WebWorkers use spoofed navigator.* useragent values

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#13027: Make WebWorkers use spoofed navigator.* useragent values
-------------------------+-------------------------------------------------
     Reporter:           |      Owner:  gk
  mikeperry              |     Status:  needs_review
         Type:  defect   |  Milestone:
     Priority:  major    |    Version:
    Component:  Tor      |   Keywords:  ff31-esr, tbb-easy, tbb-
  Browser                |  fingerprinting, TorBrowserTeam201410Easy,
   Resolution:           |  MikePerry201410R
Actual Points:           |  Parent ID:
       Points:           |
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Comment (by gk):

 Seems the bug is triggerable by a Mozmill test without Workers being
 involved at all:
 {{{
     "use strict";

     Cu.import("resource://gre/modules/Services.jsm");

     const TEST_URL = "https://www.mediawiki.org/wiki/MediaWiki";

     var setupModule = function(aModule) {
       aModule.controller = mozmill.getBrowserController();
     }

     function load_page(controller, url) {
       var retry = 4;
       while (retry-- > 0) {
         var success = true;
         controller.open(url);
         try {
           controller.waitForPageLoad(10000);
         } catch(e) {
           success = false;
         }
         if (success) {
           return true;
         }
       }
       controller.open(url);
       return controller.waitForPageLoad(50000);
     }

     var testNavigatorPlatform = function() {
       Services.prefs.setCharPref("general.platform.override", "Win32");
       load_page(controller, TEST_URL);
       let nav = controller.tabs.activeTab.defaultView.navigator;
       for (var prop in nav) {
         if (prop === "platform")
           dump("Test result for " + prop + " is: " + nav[prop]);
       }
     }
 }}}
 A Tor Browser reports on my 64 bit Linux "Linux x86_64". The same holds
 for the current Firefox release (32.0.3) and the vanilla ESR 31 but not
 for Firefox nightly/aurora/beta. That's pretty weird but might help us
 writing a proper test verifying it is indeed fixed.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13027#comment:28>
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