[tor-bugs] #24186 [Core Tor/Tor]: vote: Voting schedule is not updated before voting

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#24186: vote: Voting schedule is not updated before voting
------------------------------+--------------------------------
     Reporter:  dgoulet       |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Very High     |  Milestone:  Tor: 0.3.2.x-final
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  tor-dirauth
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 Commit e67f4441eb2646368e3e7cb1bcee403667b786f0 introduced a safeguard in
 `dirvote_get_next_valid_after_time()` in order to recalculate the voting
 schedule if it is called before it was initialized.

 Turns out that it is actually called very early for a directory authority
 with `sr_init()` thus the voting schedule is first initialized through
 that safeguard.

 That made the following check in `dirvote_act()` not work so the voting
 schedule is never recalculated using the `now` that we are about to use to
 vote with:

 {{{
   if (!voting_schedule.voting_starts) {
     ...
     dirvote_recalculate_timing(options, now);
   }
 }}}

 This lead to warnings such as (snipping some lines):

 {{{
 Nov 08 11:58:19.169 [info] Choosing expected valid-after time as
 2017-11-08 16:58:20: consensus_set=0, interval=5
 [...]
 Nov 08 11:58:20.173 [notice] Time to vote.
 [...]
 Nov 08 11:58:20.175 [notice] Choosing valid-after time in vote as
 2017-11-08 16:58:25: consensus_set=0, last_interval=5
 Nov 08 11:58:20.181 [warn] Rejecting vote from 127.0.0.1 with valid-after
 time of 2017-11-08 16:58:25; we were expecting 2017-11-08 16:58:20
 Nov 08 11:58:20.181 [warn] Couldn't store my own vote! (I told myself,
 'Bad valid-after time'.)
 }}}

 Voting schedule object was set at "11:58:19" which made a valid_after time
 to "11:58:20" but we voted at "11:58:20" without updating that schedule so
 we ended up computing a valid_after = "11:58:25" in the vote but not in
 the voting schedule.

 I *think* the fix here is to always recalculate our voting schedule when
 we are about to vote to use the "now" value maybe?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24186>
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