[tor-bugs] #25347 [Core Tor/Tor]: Tor keeps on trying the same overloaded guard over and over

[Tor Bug Tracker & Wiki]

#25347: Tor keeps on trying the same overloaded guard over and over
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 Reporter:  teor                                 |          Owner:  asn
     Type:  defect                               |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.3.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.3.0.6
 Severity:  Normal                               |     Resolution:
 Keywords:  031-backport, 032-backport,          |  Actual Points:
  033-must, tor-guard, tor-client, tbb-          |
  usability-website, tbb-needs,                  |
  033-triage-20180320, 033-included-20180320     |
Parent ID:  #21969                               |         Points:  1
 Reviewer:                                       |        Sponsor:
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Comment (by s7r):

 It is not happening that often in order to make user experience that bad
 in order to force us to take a decision that might degrade security /
 anonymity. If that would be the case we would have hundreds of reports by
 now. I an not sure how often and bad it affect popular onion services that
 run in anonymous mode, but it looks like it can wait slightly more.

 The behavior to switch guard on first `DESTROY` cell received as a client
 sounds terrible to me, I say we should NACK it. A proper behavior would be
 for clients to only relax a little bit after receiving say 10 `DESTROY`
 cells triggered by `RESOURCELIMIT` in a row, not switch the overloaded
 guard entirely just yet, then increase the time wait period between
 circuit retries so that we preserve as much as possible Tor's guard
 rotation period interval.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25347#comment:32>
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