#23764: hs-v3: No live consensus on client with a bridge
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Reporter: dgoulet | Owner: dgoulet
Type: defect | Status: new
Priority: High | Milestone: Tor:
| unspecified
Component: Core Tor/Tor | Version:
Severity: Normal | Resolution:
Keywords: tor-hs, prop224, | Actual Points:
034-triage-20180328, 034-removed-20180328 |
Parent ID: #23605 | Points:
Reviewer: | Sponsor:
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Comment (by teor):
Replying to [comment:13 dgoulet]:
> I'm gonna go on a limb here and say that this is a bit "out of scope" in
some ways or just too complicated for s8 at this stage.
I agree, I don't think we can get this done in a few weeks, but we should
do it eventually. Because Tor clients can now bootstrap and use exits with
a reasonably live consensus (or skewed clock), but they can't use v3 onion
services.
> I've gone over the thread above (which is kind of old, things have
changed a bit since then) and what I can say is that the changes would
need to happen in many places and thus require us to expand considerably
our reachability unit testing.
>
> First in `can_client_refetch_desc()` to let the client try to download a
descriptor without a live consensus.
>
> The second big part would be in `hs_get_responsible_hsdirs()` which also
requires a live consensus but also used by the service ... so some split
to be done.
No, services should also work with a reasonably live consensus. Otherwise,
people running services on small devices with skewed clocks will be sad.
> Then finaly, make `hs_get_time_period_num()` maybe fallback on the
"latest consensus" instead of `approx_time()` if the live consensus can't
be found. The idea here is that for the whole subsystem the same time
source has to be used. So having code path that use the "latest consensus
valid_after" time with approx_time is a recipe for reachability issue.
>
> We had so many issues with timing over the years and ended up realizing
that whatever we use, the entire subsystem needs to use the same time
source. In theory, right now, the "live consensus valid_after" should be
used across the board. Part of my thinks we would benefit from a "HS time
source" that is updated every time we get a new consensus and then the HS
subsystem only uses.
Sounds like we need a module that handles onion service time.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/23764#comment:14>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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