[tor-bugs] #25882 [Core Tor/Tor]: clients not detecting stale onion service introduction points

Tor Bug Tracker & Wiki blackhole at torproject.org
Mon Apr 23 02:25:51 UTC 2018


#25882: clients not detecting stale onion service introduction points
--------------------------+------------------------------------
 Reporter:  cypherpunks   |          Owner:  (none)
     Type:  defect        |         Status:  assigned
 Priority:  Medium        |      Milestone:  Tor: 0.3.4.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:  tor-hs        |  Actual Points:
Parent ID:  #22455        |         Points:
 Reviewer:                |        Sponsor:
--------------------------+------------------------------------
Changes (by arma):

 * cc: dgoulet (added)


Comment:

 I think #21600 is not as related as you might think, since I think that
 ticket is for the onion service side.

 Theory 1: the intro point went down or was otherwise unreachable, and the
 Tor client made a circuit to try to reach it, but the circuit timed out,
 and so we launch a new parallel one every second, rather than once like we
 had intended. See {{{intro_going_on_but_too_old}}} in circuituse.c.

 Also, while you're looking at that clause:
 {{{
     /* Log an info message if we're going to launch a new intro circ in
      * parallel */
     if (purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT &&
         !must_be_open && origin_circ->hs_circ_has_timed_out &&
         !circ->marked_for_close) {
         intro_going_on_but_too_old = 1;
         continue;
     }
 }}}

 It isn't until later, in circuit_is_acceptable, which we don't call
 because of the "continue", that we check that the
 origin_circ->hs_circ_has_timed_out was for *our* intended intro point,
 right? What's up with that? I'm cc'ing dgoulet since he touched that code
 recently. I guess it isn't *so* bad, since that bug only controls whether
 we log a (potentially confusing) info-level log?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25882#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online


More information about the tor-bugs mailing list