[tor-bugs] #6866 [Tor Client]: pathbias_count_first_hop(): Bug: circuitbuild.c:2650

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#6866: pathbias_count_first_hop(): Bug: circuitbuild.c:2650
------------------------+---------------------------------------------------
 Reporter:  fob         |          Owner:                    
     Type:  defect      |         Status:  new               
 Priority:  major       |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:  Tor: 0.2.3.21-rc  
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
------------------------+---------------------------------------------------
Changes (by rransom):

  * priority:  normal => major
  * milestone:  => Tor: 0.2.3.x-final


Comment:

 Replying to [ticket:6866 fob]:
 > I installed Tor 0.2.3.22-rc yesterday and after a few hours it crashes
 with this error.
 >
 > Sep 16 22:35:52.000 [err] pathbias_count_first_hop(): Bug:
 circuitbuild.c:2650: pathbias_count_first_hop: Assertion
 circ->build_state->desired_path_len == 1 failed; aborting.

 From `pathbias_count_first_hop` in `src/or/circuitbuild.c`:
 {{{
   /* Completely ignore one hop circuits */
   if (circ->build_state->onehop_tunnel) {
     tor_assert(circ->build_state->desired_path_len == 1);
     return 0;
   }
 }}}

 I see no reason for a piece of code which claims to only attempt to detect
 path-bias attacks to contain this assertion.  Someone will have to review
 that code to check for other inappropriate assertions as well before
 0.2.3.x becomes ‘stable’.


 > My torrc is default except for the following lines.
 > Tor2WebMode 1
 > CircuitBuildTimeout 10
 >
 > P.S. Tor with tor2webmode on wont work at all unless I put in the
 CircuitBuildTimeout line, it seems to default to 0 seconds which makes
 every connection time out instantly.

 That's #6304.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6866#comment:1>
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