[tbb-bugs] #16267 [Tor Browser]: NoCaptcha Recaptcha is not working because of canvas fingerprint blocking

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#16267: NoCaptcha Recaptcha is not working because of canvas fingerprint blocking
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 Reporter:  szgal        |          Owner:  tbb-team
     Type:  defect       |         Status:  new
 Priority:  major        |      Milestone:  TorBrowserBundle 2.3.x-stable
Component:  Tor Browser  |        Version:
 Keywords:               |  Actual Points:
Parent ID:               |         Points:
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 Now, the browser is blocking canvas fingerprinting. But the new ReCaptcha
 is not working without it. When I try to solve a NoCaptcha on any site
 EXCEPT google.com, there is no dialog asking whether to allow reading the
 canvas, it simply fails. I know what I need to select, but I cannot see
 the pictures.
 Repro steps:

  1. Run newest TOR browser
  1. Visit a page with recaptcha, like this:
 http://www.codediesel.com/demos/google-recaptcha/
  1. Try to solve

 Interestingly, it works on Google's page:
 http://www.google.com/recaptcha/api2/demo
 Not-so-good workaround: Open network inspector, click checkbox, look for
 something like "payload" in network inspector, view response. Now you can
 see the images.
 Workaround requiring modifications (I would like to have this option even
 if this bug is fixed): Allow user to disable canvas read blocking.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16267>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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