[tor-bugs] #31369 [Core Tor/Stem]: HSv3 descriptor support in stem

[Tor Bug Tracker & Wiki]

#31369: HSv3 descriptor support in stem
-------------------------------+-----------------------------------------
     Reporter:  asn            |      Owner:  atagar
         Type:  defect         |     Status:  new
     Priority:  Medium         |  Milestone:
    Component:  Core Tor/Stem  |    Version:
     Severity:  Normal         |   Keywords:  tor-hs onionbalance scaling
Actual Points:                 |  Parent ID:
       Points:                 |   Reviewer:
      Sponsor:  Sponsor27-can  |
-------------------------------+-----------------------------------------
 Hello,

 it would be great if stem could support v3 onion service descriptors: both
 to parse them and to generate them.

 This would be particularly useful as part of onionbalance v3 (#26768). The
 old onionbalance actually generates the descriptors itself in an ad-hoc
 way, but it would be great if we could have stem make them in the new one.

 Damian asked me for an HSFETCH command that will fetch a stable v3 onion
 desc. I used Donncha's script from here
 (https://gist.github.com/DonnchaC/13b744a1e30b7d34bc26) like this:
 `python tmp/hsfetch.py
 vww6ybal4bd7szmgncyruucpgfkqahzddi37ktceo3ah7ngmcopnpyyd.onion` and that
 gives me the riseup onion descriptor (there is no DDG v3 onion right now).

 Also, v3 descriptors are more complicated than v2 descriptors because of
 their double-layer encryption. You can see more info here:
 https://github.com/torproject/torspec/blob/master/rend-spec-v3.txt#L1046
 https://github.com/torproject/tor/blob/0acfd7dcee2a4473eba05a53d6df2d6d4fe2050b/src/feature/hs/hs_descriptor.c#L2639

 Damian, let me know how that looks like to you and how we can help. We
 plan to start working on Onionbalance v3 at mid-to-late August, but if
 this is something we can have at a reasonaable timeframe we can
 potentially delay the descriptor parts of it for some time until stem
 support exists.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31369>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online