[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 arma):

 Replying to [comment:6 arma]:
 > - i don't yet have an opinion on rransom's worry about "three
 authorities can set it to screw you". on first glance it looks like we
 don't have any other consensus params for which three auths can get
 together to harm anonymity. so we may in fact want to set tighter bounds
 on what failure percentages should cause a guard drop -- but i can't
 really speculate about that until we've resolved more of the issues i
 raise here. i wouldn't be opposed to some scheme where 3 auths acting by
 themselves are insufficient to set a consensus param; that should be a
 separate ticket if we want it.

 I think the short-term hack here can simply be for all dir auths to vote
 for "off" on this param. Then there's little risk that just 3 of them can
 force it to be something unsafe.

 That said: if there's a bug that makes the current counts wrong, then if
 we don't rip pb_disablepct out of 0.2.3, we'll need to rename the
 consensus param (use a new one) in the future after we've fixed that bug,
 or the 0.2.3.22 people will be rotating guards way more often than they
 should.

 Actually, since the feature is already in 0.2.3.x for earlier values of x,
 maybe it's too late, and the pb_disablepct name is already likely to be a
 lost cause?

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/7066#comment:11>
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