[tor-bugs] #15515 [Tor]: Don't allow multiple INTRODUCE1s on the same circuit

[Tor Bug Tracker & Wiki]

#15515: Don't allow multiple INTRODUCE1s on the same circuit
-------------------------+-------------------------------------------------
     Reporter:  asn      |      Owner:
         Type:  defect   |     Status:  needs_review
     Priority:  normal   |  Milestone:  Tor: 0.2.6.x-final
    Component:  Tor      |    Version:
   Resolution:           |   Keywords:  026-backport 025-backport
Actual Points:           |  024-backport
       Points:           |  Parent ID:  #15463
-------------------------+-------------------------------------------------

Comment (by asn):

 Replying to [comment:3 asn]:
 > some more thoughts:
 > 16:31 < qwerty1> maybe it would be better to return 0 instead of goto
 err
 > 16:31 < qwerty1> if they get a nack they will know to try a new circuit
 > 16:32 < asn> qwerty1: hm plausible. maybe we should also not waste cells
 for them.

 As discussed yesterday, I implemented this alternative behavior in a fixup
 commit on my branch `bug15515_025` which is based on nick's rebase.
 Basically, it marks the circuit as closed and does not send a NAK, if we
 detect multiple `INTRODUCE1` cells.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15515#comment:9>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online