[tor-bugs] #5394 [Tor Client]: warn users about their clock if they see a consensus from the future

[Tor Bug Tracker & Wiki]

#5394: warn users about their clock if they see a consensus from the future
------------------------+---------------------------------------------------
 Reporter:  arma        |          Owner:                    
     Type:  defect      |         Status:  new               
 Priority:  normal      |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:                    
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
------------------------+---------------------------------------------------
 In router_set_networkstatus_v2() we check if the v2 ns is from the future,
 and warn if so:
 {{{
   if (ns->published_on > now + NETWORKSTATUS_ALLOW_SKEW) {
     char dbuf[64];
     long delta = now - ns->published_on;
     format_time_interval(dbuf, sizeof(dbuf), delta);
     log_warn(LD_GENERAL, "Network status from %s was published %s in the "
              "future (%s GMT). Check your time and date settings! "
              "Not caching.",
              source_desc, dbuf, published);
     control_event_general_status(LOG_WARN,
                        "CLOCK_SKEW MIN_SKEW=%ld
 SOURCE=NETWORKSTATUS:%s:%d",
                        delta, ns->source_address, ns->source_dirport);
     skewed = 1;
   }
 }}}

 We should do something similar for v3 consensuses.

 Also, we might want to use a smaller value than '24 hours' for skew
 tolerance, since there's really no realistic way a consensus will validly
 appear from even the near future.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5394>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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