[tor-bugs] #6530 [Tor Relay]: Out-of-bounds read in networkstatus_parse_vote_from_string()

["Tor Bug Tracker & Wiki" <torproject-admin@xxxxxxxxxxxxxx>]

#6530: Out-of-bounds read in networkstatus_parse_vote_from_string()
-----------------------+----------------------------------------------------
 Reporter:  asn        |          Owner:                    
     Type:  defect     |         Status:  new               
 Priority:  major      |      Milestone:  Tor: 0.2.2.x-final
Component:  Tor Relay  |        Version:                    
 Keywords:             |         Parent:                    
   Points:             |   Actualpoints:                    
-----------------------+----------------------------------------------------
 {{{
   tok = find_by_keyword(tokens, K_NETWORK_STATUS_VERSION);
   tor_assert(tok);
   if (tok->n_args > 1) {
     int flavor = networkstatus_parse_flavor_name(tok->args[1]);
     if (flavor < 0) {
       log_warn(LD_DIR, "Can't parse document with unknown flavor %s",
                escaped(tok->args[2]));
       goto err;
     }
     ns->flavor = flav = flavor;
   }
 }}}

 `networkstatus_parse_vote_from_string()` validates the '''second'''
 argument of `network-status-version` which is the flavor of the
 consensus. If the flavor is invalid it log_warn()s the '''third'''
 argument which is not guaranteed to exist. This means that `escaped()`
 receives a non-allocated section of memory as its argument and treats it
 as a pointer to a string; this should lead to a segfault.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6530>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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