[tor-bugs] #30466 [Core Tor/Tor]: hs: Do not allow more than one control cell on a circuit

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#30466: hs: Do not allow more than one control cell on a circuit
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 Reporter:  dgoulet                     |          Owner:  neel
     Type:  defect                      |         Status:
                                        |  needs_information
 Priority:  Medium                      |      Milestone:  Tor: unspecified
Component:  Core Tor/Tor                |        Version:
 Severity:  Normal                      |     Resolution:
 Keywords:  tor-dos, tor-hs, tor-relay  |  Actual Points:
Parent ID:                              |         Points:  0.1
 Reviewer:  dgoulet                     |        Sponsor:  Sponsor27-can
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Changes (by dgoulet):

 * status:  needs_review => needs_information


Comment:

 This approach is sensible and code seems accurate. But we should put this
 one on hold for now.

 The reason is that there might be some cells, for instance
 `ESTABLISH_INTRO`, that we will want to be able to send multiple times
 during the lifetime of the circuit. (Relevant to #30924).

 These control cells could be useful for DoS mitigation systems in order to
 be able to tell different HS entity on how to behave coming from the
 service.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30466#comment:6>
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