[tor-bugs] #33541 [Applications/Tor Browser]: fingerprinting: zoom.min/maxPercent should be fixed at 100

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#33541: fingerprinting: zoom.min/maxPercent should be fixed at 100
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 Reporter:  cypherpunks                    |          Owner:  tbb-team
     Type:  defect                         |         Status:  new
 Priority:  Medium                         |      Milestone:
Component:  Applications/Tor Browser       |        Version:
 Severity:  Normal                         |     Resolution:
 Keywords:  tbb-fingerprinting-resolution  |  Actual Points:
Parent ID:                                 |         Points:
 Reviewer:                                 |        Sponsor:
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Changes (by Thorin):

 * keywords:   => tbb-fingerprinting-resolution
 * priority:  High => Medium


Comment:

 Site-specific zoom settings are disabled. And new windows/tabs always
 start with 100%. But any zoom set on a tab **remains** until reset/changed
 - even if the domain changes.

 Zoom affects almost everything (as you can see from my test) - all the
 measurements, dpi, dppx, dpcm, devicePixelRatio etc, you can just use the
 size of an element.... and so on.

 But, in general, everyone would be the same: i.e everyone starts at
 1000x1000px, they zoom to 133% and everyone returns 750x750. There's no
 entropy here

 I do not think disabling zoom is the answer: accessibility issues and
 different threat models and all that. But what could be tightened is that
 zoom is reset to 100% on a domain change **per tab**

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33541#comment:1>
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