[tor-bugs] #6537 [Tor Client]: Possible timing side-channel in router selection

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#6537: Possible timing side-channel in router selection
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    Reporter:  nickm       |       Owner:                    
        Type:  defect      |      Status:  closed            
    Priority:  major       |   Milestone:  Tor: 0.2.2.x-final
   Component:  Tor Client  |     Version:                    
  Resolution:  fixed       |    Keywords:                    
      Parent:              |      Points:                    
Actualpoints:              |  
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Comment(by cypherpunks):

 No one of smartlists used by router selection funcs is strongly sorted.
 Order of it members is depend by limits from launch_descriptor_downloads()
 and by network timings from connection_dir_client_reached_eof(). Two
 different clients has differently ordered smartlists in result.

 How could attacker using cpu-time of router selection funcs if attacker
 can't be sure about lists' order?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6537#comment:3>
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