[tor-bugs] #27735 [Core Tor/Tor]: Tors with cached consensuses can't upgrade to a version that stops supporting a required protocol

[Tor Bug Tracker & Wiki]

#27735: Tors with cached consensuses can't upgrade to a version that stops
supporting a required protocol
-------------------------+-------------------------------------------------
     Reporter:  teor     |      Owner:  (none)
         Type:  defect   |     Status:  new
     Priority:  Medium   |  Milestone:  Tor: 0.3.5.x-final
    Component:  Core     |    Version:
  Tor/Tor                |   Keywords:  029-backport-maybe, 032-backport-
     Severity:  Normal   |  maybe, 033-backport-maybe, 034-backport-maybe
Actual Points:           |  Parent ID:  #27288
       Points:           |   Reviewer:
      Sponsor:           |
-------------------------+-------------------------------------------------
 When Tor loads the cached consensus, it checks the protocols in that
 consensus, and then exits if it does not have any required protocols.
 These checks happen before signatures and expiry are checked. (And before
 trying to get a new consensus.)

 This makes it impossible for a Tor with a cached consensus to stop
 supporting a protocol required in that consensus.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27735>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online