[tor-bugs] #7066 [Tor]: Guard disablement by path-bias detector must be disabled or removed

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#7066: Guard disablement by path-bias detector must be disabled or removed
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 Reporter:  rransom     |          Owner:                    
     Type:  defect      |         Status:  needs_revision    
 Priority:  blocker     |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor         |        Version:                    
 Keywords:  tor-client  |         Parent:                    
   Points:              |   Actualpoints:                    
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Comment(by mikeperry):

 Replying to [comment:4 rransom]:
 > Replying to [comment:2 nickm]:
 > > Please review branch "neuter_pathbias" in my public repository.
 >
 > The changes/ file is wrong -- the problem isn't that pb_disablepct could
 keep clients from building circuits at all (although it would have that
 effect on clients which use bridges); the problem is that pb_disablepct is
 a user-tracing backdoor which can be used to cause clients to cycle
 through all the available Guard nodes as entry nodes.

 Can you explain the attack vector here? Should we disable all of our
 consensus parameter support?

 > Other than that, looks good for 0.2.3.x (I grepped for
 “`path_bias_disabled`” on that branch and didn't find anything else that
 turns it on).  There will be a merge conflict on 0.2.4.x.

 I do not believe this is the right way to disable the guard rotation
 features for 0.2.3.x. Please see my proposal, particularly the last
 section "Implementation Notes: Differences between proposal and current
 source".

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7066#comment:5>
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