[tor-bugs] #7265 [Firefox Patch Issues]: Only display Canvas message for first parties; simply log third parties

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#7265: Only display Canvas message for first parties; simply log third parties
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 Reporter:  mikeperry                                        |          Owner:  mikeperry   
     Type:  enhancement                                      |         Status:  needs_review
 Priority:  major                                            |      Milestone:              
Component:  Firefox Patch Issues                             |        Version:              
 Keywords:  tbb-fingerprinting, tbb-bounty, MikePerry201307  |         Parent:              
   Points:                                                   |   Actualpoints:              
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Comment(by mcs):

 Replying to [comment:8 gk]:
 > http://getfoxyproxy.org/
 > http://foundation.zurb.com/
 >
 > But I am still not sure what exactly is causing the prompts in these
 cases. On the FoxyProxy page that is probably due to Modernizr which
 checks browser features. But even there a cursory glimpse at the source
 code did not convince me that this is not a false positive. I don't have a
 clue why the prompt is shown on foundation.zurb.com yet.

 It looks like both of those sites use a JS framework named Foundation or a
 close relative (see http://foundation.zurb.com/).  That framework uses a
 canvas to render some text and then uses toDataURL() to grab an image of
 it... so this is not a false positive.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7265#comment:9>
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