[tor-bugs] #24509 [Core Tor/Tor]: circuit_can_use_tap() should only allow TAP for v2 onion services

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#24509: circuit_can_use_tap() should only allow TAP for v2 onion services
-------------------------------------------------+-------------------------
 Reporter:  teor                                 |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.3.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.3.2.1-alpha
 Severity:  Normal                               |     Resolution:
 Keywords:  prop224, tor-hs, security-low,       |  Actual Points:
  easy, intro                                    |
Parent ID:                                       |         Points:  0.5
 Reviewer:                                       |        Sponsor:
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Changes (by dgoulet):

 * status:  needs_review => needs_revision


Comment:

 Replying to [comment:1 irl]:
 > The above patch uses `circ->rend_data->version` to determine the onion
 service version in use for the circuit. There is an assert that that
 structure exists before trying to dereference the version from it, which I
 think it should always be the case that it does exist unless there are
 maybe Tor2Web things I'm unfamiliar with.

 Unfortunately, that won't work. We introduced the `rend_data` version back
 before we did prop224 because we were planning on using a specialized
 version for v3 but it turns out that it wasn't really usable the way we
 wanted. We should probably also add a big comment in `rend_data_t` to tell
 the world that it is ONLY for v2 even thought a version field exists and
 all this ABI/API business.

 So v2 circuits have a `rend_data` object attached and v3 circuits have an
 `hs_ident` object.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24509#comment:2>
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