[tbb-bugs] #18560 [Applications/Tor Browser]: WEBGL_debug_renderer_info extension may leak information about graphics driver

[Tor Bug Tracker & Wiki]

#18560: WEBGL_debug_renderer_info extension may leak information about graphics
driver
-------------------------------------------------+-------------------------
 Reporter:  gk                                   |          Owner:  tbb-
                                                 |  team
     Type:  defect                               |         Status:
                                                 |  needs_review
 Priority:  High                                 |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  ff52-esr, tbb-fingerprinting,        |  Actual Points:
  tbb-7.0-must-alpha                             |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:  None
-------------------------------------------------+-------------------------
Changes (by arthuredelstein):

 * status:  new => needs_review


Comment:

 In 52ESR, this extension [https://dxr.mozilla.org/mozilla-
 esr52/rev/cb606065c4c1f021a03421eff069d64032cf9b4a/modules/libpref/init/all.js#4497
 remains disabled] in Beta and Release channels.

 Moreover, in Tor Browser, we [https://gitweb.torproject.org/tor-
 browser.git/tree/browser/app/profile/000-tor-browser.js?h=tor-
 browser-52.1.0esr-7.0-2#n112 have] `pref("webgl.disable-extensions",
 true)`, which means that all webgl extensions are disabled (including
 WEBGL_debug_renderer_info).

 To be extra sure, I manually confirmed in TBB 7.0a3 that entering
 {{{
 document.createElement("canvas").getContext("experimental-
 webgl").getSupportedExtensions();
 }}}
 in a content JS console returns an empty array.

 We could postpone this ticket again to ff59-esr, but as long as we are
 disabling all extensions, I think the conclusion will be the same. Setting
 to needs_review to see if my colleagues want to keep this ticket open.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18560#comment:4>
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