[tor-bugs] #3375 [Tor Client]: NEWNYM does not abandon open rendezvous circuits

[Tor Bug Tracker & Wiki]

#3375: NEWNYM does not abandon open rendezvous circuits
------------------------+---------------------------------------------------
 Reporter:  rransom     |          Owner:  rransom           
     Type:  defect      |         Status:  needs_review      
 Priority:  major       |      Milestone:  Tor: 0.2.1.x-final
Component:  Tor Client  |        Version:                    
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
------------------------+---------------------------------------------------
Changes (by arma):

  * priority:  critical => major


Comment:

 Replying to [comment:4 nickm]:
 > Replying to [comment:3 rransom]:
 > > A rendezvous circuit's `timestamp_dirty` is reset every time a stream
 is attached to it,
 >
 > Ow.  This gives timestamp_dirty a different meaning for rendezvous
 circuits than for general circuits, where (unless I'm mistaken) only the
 first stream getting attached causes the circuit timestamp_dirty to get
 set.

 Correct. The idea was that the rendezvous process is expensive, so as long
 as you're still interacting with the hidden service, we should make it
 over the same circuit.

 Because we don't rotate circuits every 10 minutes for hidden services, a)
 interactions are faster and smoother, and b) interactions are more
 linkable.

 > > so this change would only cause clients to reintroduce to a hidden
 service if they had a long-lived stream open and had not opened a new
 stream to the HS in the last 10 minutes.  (If they don't have a long-lived
 stream open, Tor will currently close the circuit 10 minutes after the
 last time a stream was attached to it)  I don't see a problem with using a
 new circuit in that case, and it may be beneficial (e.g. for reliability
 reasons).
 >
 > I think that's _probably_ ok too, but it's definitely a behavior change,
 and as such I'm not too thrilled about having it in 0.2.1.x.

 It is definitely a behavior change. But I pondered the patch for a while
 and I think it should be ok to apply, either to 0.2.1 directly or to 0.2.2
 with plans to backport 'sometime'.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/3375#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online