[tor-bugs] #28184 [Core Tor/Tor]: Reload is additive with regards to new v3 HS client authorizations but it won't subtract deleted ones

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#28184: Reload is additive with regards to new v3 HS client authorizations but it
won't subtract deleted ones
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 Reporter:  jchevali      |          Owner:  haxxpop
     Type:  defect        |         Status:  closed
 Priority:  Medium        |      Milestone:  Tor: 0.3.5.x-final
Component:  Core Tor/Tor  |        Version:  Tor: 0.3.5.2-alpha
 Severity:  Normal        |     Resolution:  wontfix
 Keywords:  tor-hs        |  Actual Points:
Parent ID:                |         Points:
 Reviewer:  asn           |        Sponsor:
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Changes (by dgoulet):

 * status:  needs_information => closed
 * resolution:   => wontfix


Comment:

 > I mean we should refetch only when we can't decode or can't use the IPs.
 It shouldn't be triggered by anything else like when the client change the
 auth config, or anything else. Otherwise, I think the code will be too
 complex.

 Data point to this. The tor client stores the descriptor *decoded* in the
 cache so my statement earlier was wrong that if the client authorization
 file is changed for a .onion for which we have a descriptor in our cache,
 it won't matter, tor will still use the descriptor because it is
 completely decoded (including decrypted ofc).

 Few observations I took the time to go over:

 1. The client cache does *not* store an undecodable descriptor so we don't
 have the problem of having "unusable descriptor" in our cache, they can
 only be unusable if the IPs aren't working (basically what I said above).

 2. If we can't decode a descriptor, tor will try a new HSDir until it runs
 out of HSDir to ask and then the SOCKS connection is cut off.

 3. If the intro points are unusable, tor client will do a refetch. And
 this will happen like (2) as in every HSDir will be queried until none
 remains. See `hs_client_any_intro_points_usable()`.

 Which means that all in all, I will close this ticket for now. If we want
 to improve something that I might have missed, lets open a new simpler
 ticket about it.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28184#comment:12>
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