[tor-bugs] #17945 [Core Tor/Tor]: Stop Tor2Web connecting to (Rendezvous) Single Onion Services

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#17945: Stop Tor2Web connecting to (Rendezvous) Single Onion Services
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 Reporter:  teor                        |          Owner:
     Type:  enhancement                 |         Status:  new
 Priority:  Medium                      |      Milestone:  Tor: 0.2.???
Component:  Core Tor/Tor                |        Version:
 Severity:  Normal                      |     Resolution:
 Keywords:  rsos, sos, tor2web, tor-hs  |  Actual Points:
Parent ID:                              |         Points:  small/medium
 Reviewer:                              |        Sponsor:
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Comment (by teor):

 Replying to [comment:8 teor]:
 > Replying to [comment:1 teor]:
 > > Replying to [ticket:17945 teor]:
 > > > Tor2Web clients make a one-hop connection to the rendezvous point.
 Rendezvous Single Onion Services also make a one-hop connection to the
 rendezvous point. (Single Onion Services expect a client to make an extend
 request to the Single Onion Service at the end of a 3-hop path.)
 > > The rendezvous point (and possibly the introduction point) could
 terminate the connection if it has a single hop on both ends. This seems
 to be the most correct option.
 >
 > This could result in false positives if the consensus gets out of sync.
 > Or is there a reliable way for a relay to detect non-relays without
 using the consensus?
 > (How does the padding do it?)

 arma says on tor-project@ that we can do it the same way exits do it - by
 aggressively fetching the consensus from the authorities. (Fortunately,
 fallback directories in 0.2.8 will reduce the client load on authorities,
 allowing relays scope to do this.)

 Then we can teach single onion services to advertise their single-hop
 nature in their descriptors, and tor2web and similar clients to build
 multi-hop paths to intro and rendezvous points for those services.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17945#comment:9>
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