[tor-bugs] #8976 [Tor]: rend_service_introduce() doesn't notice if the rendezvous point is on 127.0.0.1

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#8976: rend_service_introduce() doesn't notice if the rendezvous point is on
127.0.0.1
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 Reporter:  arma      |          Owner:
     Type:  defect    |         Status:  needs_review
 Priority:  Medium    |      Milestone:  Tor: 0.2.8.x-final
Component:  Tor       |        Version:
 Severity:  Normal    |     Resolution:
 Keywords:  tor-hs    |  Actual Points:
Parent ID:  #17674    |         Points:
  Sponsor:  SponsorR  |
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Comment (by dgoulet):

 I've done an experiment for that and you can see my summary here:
 https://trac.torproject.org/projects/tor/ticket/17674#comment:6

 This is not entirely fixed by the parent ticket. We still have an issue of
 wasted resources if we don't catch it when we parse the intro cell.

 We should stop that once we have the INTRODUCE2 payload and just refuse it
 which would save us some resources instead of going through the whole
 process of extending at the second middle node and failing.

 Here is a branch with a fix: `bug8976_01_028`.

 I've added a function to check if we are allow to extend to a given
 address. We are starting to use this code pattern at multiple place now so
 better have a call that validates it. If we like this, we should use it
 also in #17674.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8976#comment:8>
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