[tor-bugs] #18710 [Core Tor/Tor]: dnsserv.c asserts when no supported questions are requested

[Tor Bug Tracker & Wiki]

#18710: dnsserv.c asserts when no supported questions are requested
-------------------------------------------------+-------------------------
 Reporter:  geekmug                              |          Owner:
     Type:  defect                               |         Status:
 Priority:  Very High                            |  needs_review
Component:  Core Tor/Tor                         |      Milestone:  Tor:
 Severity:  Normal                               |  0.2.8.x-final
 Keywords:  dns dnsport tor-client 027-backport  |        Version:  Tor:
  TorCoreTeam201604                              |  0.2.7.6
Parent ID:                                       |     Resolution:
 Reviewer:  nickm                                |  Actual Points:
                                                 |         Points:
                                                 |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by nickm):

 It looks like this code, currently in dnsserv.c, prevents us from reaching
 the assert?

 {{{
   if (err != DNS_ERR_NONE || !supported_q) {
     /* We got an error?  There's no question we're willing to answer? Then
      * send back an answer immediately; we're done. */
     evdns_server_request_respond(req, err);
     return;
   }
 }}}

 The code as it stands _does_ look wrong, though.  And it looks like
 qtype_all would also have hit this test.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18710#comment:5>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online