[tor-bugs] #4212 [Tor Hidden Services]: Circuit in CIRCUIT_PURPOSE_C_INTRODUCING with no rend_data

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#4212: Circuit in CIRCUIT_PURPOSE_C_INTRODUCING with no rend_data
---------------------------------+------------------------------------------
 Reporter:  rransom              |          Owner:                    
     Type:  defect               |         Status:  new               
 Priority:  major                |      Milestone:  Tor: 0.2.2.x-final
Component:  Tor Hidden Services  |        Version:                    
 Keywords:                       |         Parent:                    
   Points:                       |   Actualpoints:                    
---------------------------------+------------------------------------------
 With a somewhat recent Git master (commit
 [https://gitweb.torproject.org/tor.git/shortlog/2725a88d5e3ec362a4f866f53c26ca20f943eb49
 2725a88d5e3ec362a4f866f53c26ca20f943eb49]):
 {{{
 Oct 09 19:13:41.000 [info] circuit_expire_building(): Abandoning circ
 [redacted] (state 3:open, purpose 6)
 Oct 09 19:13:41.000 [info] internal (high-uptime) circ (length 4):
 [redacted](open) [redacted](open) [redacted](open) [redacted](open)
 Oct 09 19:13:41.000 [err] _circuit_mark_for_close(): Bug:
 circuitlist.c:1222: _circuit_mark_for_close: Assertion ocirc->rend_data
 failed; aborting.
 }}}

 (`CIRCUIT_PURPOSE_C_INTRODUCING == 6`)

 The assertion occurred in the following chunk of code, added to help fix
 #3825:
 {{{
  } else if (circ->purpose == CIRCUIT_PURPOSE_C_INTRODUCING &&
              reason != END_STREAM_REASON_TIMEOUT) {
     origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
     tor_assert(ocirc->build_state->chosen_exit);
     tor_assert(ocirc->rend_data);
     log_info(LD_REND, "Failed intro circ %s to %s "
              "(building circuit to intro point). "
              "Marking intro point as possibly unreachable.",
              safe_str_client(ocirc->rend_data->onion_address),
 safe_str_client(build_state_get_exit_nickname(ocirc->build_state)));
 rend_client_report_intro_point_failure(ocirc->build_state->chosen_exit,
                                            ocirc->rend_data,
 INTRO_POINT_FAILURE_UNREACHABLE);
 }}}

 But we should never have a circuit with that purpose with its `rend_data`
 field unset.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4212>
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