[tor-bugs] #29927 [Core Tor/Tor]: Tor protocol errors causing silent dropped cells

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#29927: Tor protocol errors causing silent dropped cells
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 Reporter:  mikeperry     |          Owner:  (none)
     Type:  defect        |         Status:  new
 Priority:  Medium        |      Milestone:
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:  tor-hs        |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
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Description changed by mikeperry:

Old description:

> While testing vanguards, I've got some mystery cases client side where
> circuits are getting closed with END_CIRC_REASON_TORPROTOCOL, but Tor is
> not emmitting any log lines that correspond to this. This is happening
> for circuits with purposes CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED and
> CIRCUIT_PURPOSE_C_GENERAL.
>
> Additionally, CIRCUIT_PURPOSE_C_INTRODUCE_ACKED circuits are getting
> closed with a END_CIRC_REASON_FINISHED after receiving an invalid cell,
> seemingly after they are done being used.
>
> See also https://github.com/mikeperry-tor/vanguards/issues/37

New description:

 While testing vanguards, I've got some mystery cases client side where
 circuits are getting closed with END_CIRC_REASON_TORPROTOCOL, but Tor is
 not emmitting any log lines that correspond to this, even at debug level.

 This is happening for circuits with purpose
 CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED. Additionally, all circuits seem
 able to fail during construction with END_CIRC_REASON_TORPROTOCOL, with no
 Tor log messages even at debug loglevel. Possibly more ntor handshake
 failures, similar to #29700?

 Finally, CIRCUIT_PURPOSE_C_INTRODUCE_ACKED circuits are getting closed
 with a END_CIRC_REASON_FINISHED after receiving an invalid cell, seemingly
 after they are done being used.

 See also https://github.com/mikeperry-tor/vanguards/issues/37

 The vanguards addon now outputs this bug number at INFO log level when
 this happens.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/29927#comment:1>
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