[tor-bugs] #20852 [Core Tor/Tor]: prop224: Update HSDir prop224 code based on newest descriptor changes

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#20852: prop224: Update HSDir prop224 code based on newest descriptor changes
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  asn
     Type:  defect                               |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.0.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-hs, prop224, TorCoreTeam201612,  |  Actual Points:
  review-group-14                                |
Parent ID:                                       |         Points:  3
 Reviewer:  dgoulet                              |        Sponsor:
                                                 |  SponsorR-can
-------------------------------------------------+-------------------------
Changes (by dgoulet):

 * status:  needs_review => needs_revision
 * reviewer:   => dgoulet


Comment:

 Replying to [comment:4 asn]:
 > Please find an initial version of (a) in my branch `bug20852`:
 > https://gitweb.torproject.org/user/asn/tor.git/log/?h=bug20852
 >
 > It basically does two things:
 > - Changes `encrypted` to `superencrypted` in the outter HS desc layer.
 > - Changes the max descriptor size to 50kb and introduces a consensus
 param `HSV3MaxDescriptorSize` that controls it.

 I like that this can be controlled by a consensus parameters which will be
 very helpful because we also plan to have a param for the number of
 introduction points which will ultimately affect the max size.

 One thing I would change is `hs_cache_get_max_hs_descriptor_size()`. The
 second "hs" in there is redundant as we are already in the HS subsystem
 here so `hs_cache_get_max_descriptor_size()" is enough imo.

 Also, `networkstatus_get_param()` returns a `int32_t` so we should NOT
 make it `unsigned int` for the max size but rather make sure we are in
 range and convert it before return. Even though it's probably not possible
 to have something not in range of what we ask, MORE safety net is good.

 >
 > I believe these two things address everything that was pending in
 prop224 and has to do with HSDir parsing of HS descriptors. Please check
 out the branch. I'm gonna do another pass of prop224 to make sure I didn't
 miss something.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20852#comment:7>
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