[tor-bugs] #27288 [Core Tor/Tor]: Tor with NSS must not claim to support LinkAuth=1

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#27288: Tor with NSS must not claim to support LinkAuth=1
-------------------------------------------------+-------------------------
 Reporter:  nickm                                |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  reopened
 Priority:  Immediate                            |      Milestone:  Tor:
                                                 |  0.3.5.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Blocker                              |     Resolution:
 Keywords:  035-roadmap-master, 035-triaged-     |  Actual Points:
  in-20180711, rust                              |
Parent ID:  #26631                               |         Points:
 Reviewer:  teor                                 |        Sponsor:
                                                 |  Sponsor8
-------------------------------------------------+-------------------------
Changes (by teor):

 * priority:  Medium => Immediate
 * status:  closed => reopened
 * resolution:  implemented =>
 * severity:  Normal => Blocker


Comment:

 Replying to [comment:7 nickm]:
 > Enough authorities are now voting not to include LinkAuth=1.  I'll
 cherry-pick this commit to master.

 Please revert this change.

 When loading the consensus from disk, Tor does the protocol check *before*
 we do the consensus expiry check:
 https://github.com/torproject/tor/blob/b67f3b751a277fb940b155c0bc64f594db5549b0/src/feature/nodelist/networkstatus.c#L1871

 Therefore, any Tor that has an old cached consensus, and deploys this
 code, will restart in a loop without ever downloading a new consensus.

 Thanks to traumschule for this bug report.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27288#comment:8>
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