[tor-bugs] #27471 [Core Tor/Tor]: HS intermittently fails: Non-fatal assertion failed in send_introduce1

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#27471: HS intermittently fails: Non-fatal assertion failed in send_introduce1
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 Reporter:  tgragnato            |          Owner:  dgoulet
     Type:  defect               |         Status:  accepted
 Priority:  Very High            |      Milestone:  Tor: 0.3.5.x-final
Component:  Core Tor/Tor         |        Version:  Tor: 0.3.4.7-rc
 Severity:  Minor                |     Resolution:
 Keywords:  tor-hs, regression?  |  Actual Points:
Parent ID:                       |         Points:
 Reviewer:                       |        Sponsor:
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Comment (by asn):

 Replying to [comment:4 dgoulet]:
 > I'm still unsure why this happened but it is clear that the RP/IP
 circuit were established. Once the RP ACKed the request, the
 authentication key in the IP `hs_ident` wasn't the one in the descriptor.
 >
 > So between the initial requests for that .onion and the ACK from the RP,
 the descriptor simply changed and the tor client fetched/stored it.
 >


 Hm, plausible.

 > That makes me think that when we store a *new* HS descriptor for A.onion
 that is we already had one in our cache and we are getting a new one, we
 should probably close every circuits related to the old one? Probably
 something like going over the IP in the old one, if they are different
 from the new one, close any related circuits.
 >
 > That way, we don't end up with leftover circuit for the *same* A.onion
 but with outdated data.

 Hm, how does v2 handle this situation?

 Also, the above fix seems plausible, but it engineering to be fixed.
 Another approach would be to gracefully handle this error, and let the Tor
 client handle it on its own by trying the next intro point (from the new
 desc this time)?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27471#comment:5>
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