[tor-bugs] #1517 [Tor Browser]: Provide JS with reduced time precision

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#1517: Provide JS with reduced time precision
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     Reporter:           |      Owner:
  mikeperry              |     Status:  closed
         Type:           |  Milestone:
  enhancement            |    Version:
     Priority:  major    |   Keywords:  backport-to-mozilla, tbb-torbutton,
    Component:  Tor      |  tbb-fingerprinting-time-highres, ff38-esr,
  Browser                |  TorBrowserTeam201505R, PearlCrescent201505R
   Resolution:  fixed    |  Parent ID:
Actual Points:           |
       Points:  10       |
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Changes (by mikeperry):

 * status:  needs_review => closed
 * resolution:   => fixed


Comment:

 I looked into this more, and noticed one case where ToSeconds() was
 exposed to content. AnimationFrame events have an elapsedTime field. I
 truncated that timestamp to millisecond accuracy (though in reality, the
 timestamps were varying by as much as 20ms for me).

 I didn't see any other leaks to content by either ToSeconds or
 ToMilliseconds.. I pushed this to tor-browser-31.7.0esr-5.0-1 for 5.0a1 as
 commit dcd5fcc102a3eb19c20013542fa3ca399db66da4.

 Calling this 'fixed' for now, but I imagine we'll have a fun time testing
 everything and deciding what to do about breakage, and we'll want to
 revisit this for ff38-esr.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/1517#comment:32>
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