[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: [tor-bugs] #18050 [Tor]: Relay submitted a descriptor with 0 DirPort due to a self-test race condition
#18050: Relay submitted a descriptor with 0 DirPort due to a self-test race
condition
-------------------------------------------------+-------------------------
Reporter: teor | Owner:
Type: defect | Status: new
Priority: Medium | Milestone: Tor:
Component: Tor | 0.2.8.x-final
Severity: Normal | Version: Tor:
Keywords: 026-maybe-backport, 027-maybe- | 0.2.6.10
backport | Resolution:
Parent ID: | Actual Points:
Sponsor: | Points:
-------------------------------------------------+-------------------------
Comment (by teor):
Replying to [comment:3 starlight]:
> Looked briefly at local logs and the logic. Current design appears to
always publish a descriptor with DirPort=0 during boot.
`run_scheduled_events()` publishes a changed descriptor once every 60
seconds, and the typical boot sequence runs the DirPort reachability at
slightly over 60 seconds from start.
> ...
> When this happens just before the consensus vote time at minute 50 of
each hour, the race condition identified by Teor occurs. Reexamined half
of the above events and in all cases problem descriptor was published at
46-49 minutes.
>
> Perhaps `consider_publishable_server()` should be adjusted to delay the
descriptor until the DirPort test is complete.
I agree.
This sounds somewhat similar to #17782. When its address changes, tor
doesn't test ORPort reachability. So it will go ahead and publish a
descriptor with the wrong address, as long as an old address was reachable
at some point.
We should make tor wait for ORPort and DirPort reachability every time:
* it starts up,
* the config changes address, ORPort, or DirPort.
There's a drawback here, which is that tor won't ever publish a descriptor
if only the ORPort is reachable (perhaps due to a broken firewall config).
I think we should have a timeout after which tor warns, then publishes the
descriptor without the DirPort. Given the time ranges we're seeing, the
timeout should be at least 20 minutes.
(Relays with no DirPort will still be used for directory requests once
#12538 is merged.)
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18050#comment:4>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
_______________________________________________
tor-bugs mailing list
tor-bugs@xxxxxxxxxxxxxxxxxxxx
https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-bugs