[tor-bugs] #32040 [Core Tor/Tor]: HS intro padding machine reactivates after receiving INTRODUCE_ACK

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#32040: HS intro padding machine reactivates after receiving INTRODUCE_ACK
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  asn
     Type:  defect                               |         Status:
                                                 |  assigned
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.4.4.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  wtf-pad, padding, circpad-           |  Actual Points:
  researchers-want, 043-deferred                 |
Parent ID:                                       |         Points:  1
 Reviewer:                                       |        Sponsor:
                                                 |  Sponsor2
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Comment (by mikeperry):

 Actually, no. No protover is required. Only client upgrade is needed, so
 no negotiation needs to happen. The things you can do with just endpoint
 upgrade are pretty crazy, if you spend a second thinking about it, as
 opposed to trying to define tokens endlessly in a committee of dinos...

 We just can remove CIRCUIT_PURPOSE_C_INTRODUCE_ACKED from
 apply_purpose_mask and set it and CIRCUIT_PURPOSE_C_INTRODUCING in
 keep_purpose_mask.

 This is done in this commit: https://github.com/mikeperry-
 tor/tor/commit/2b7b8a7cfd1124ec689e26439178cc312cf5c7d3

 The rend machines might need a similar fix if the REND circuit also has
 purpose flapping? I did not do that yet.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32040#comment:10>
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