[tor-bugs] #24894 [Core Tor/Tor]: v3 onion services don't respect MAX_REND_FAILURES

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#24894: v3 onion services don't respect MAX_REND_FAILURES
------------------------------+--------------------------------
     Reporter:  arma          |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:  Tor: 0.3.3.x-final
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 In can_relaunch_service_rendezvous_point() we check
 {{{
   if (circ->build_state->failure_count > MAX_REND_FAILURES ||
       circ->build_state->expiry_time <= time(NULL)) {
 }}}
 for whether to abort the relaunch.

 But in retry_service_rendezvous_point(), we do this:
 {{{
   /* Transfer build state information to the new circuit state in part to
    * catch any other failures. */
   new_circ->build_state->failure_count = bstate->failure_count++;
 }}}

 That ++ increments the failure_count for the *old* circuit, which means
 the new circuit gets a failure_count of 0. No new circuits ever have a
 failure count of anything other than 0.

 The legacy onion services handle it better, by doing
 {{{
   newstate->failure_count = oldstate->failure_count+1;
 }}}

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24894>
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