[tor-bugs] #28511 [Core Tor/Tor]: Limit the number of open testing circuits, and the total number of testing circuits
Tor Bug Tracker & Wiki
blackhole at torproject.org
Mon Nov 19 03:24:17 UTC 2018
#28511: Limit the number of open testing circuits, and the total number of testing
circuits
-------------------------+-------------------------------------------------
Reporter: teor | Owner: (none)
Type: defect | Status: new
Priority: Medium | Milestone: Tor: 0.4.0.x-final
Component: Core | Version:
Tor/Tor | Keywords: tor-bwauth, tor-dos, 035-backport,
Severity: Normal | 034-backport-maybe, 033-backport-maybe, 029
| -backport-maybe-not
Actual Points: | Parent ID: #22453
Points: | Reviewer:
Sponsor: |
-------------------------+-------------------------------------------------
Tor relays can open many more testing circuits than they need:
When Tor is doing its first ORPort reachability test, it initiates one
testing circuit after the first successful circuit, then one testing
circuit per second until the ORPort is found reachable. Then it gives up
after 20 minutes. (1200 circuits is definitely too many.)
When tor receives any descriptor or consensus, it does another ORPort
reachability test, and initiates a testing circuit.
When a testing circuit opens, and there aren't enough testing circuits to
test bandwidth, then tor initiates another testing circuit.
When a testing circuit expires, tor doesn't stop opening testing circuits
to replace it.
We should place a timeout on bandwidth testing, a limit on the number of
open testing circuits, and a limit on the total number of testing circuits
that tor will builds over a certain time. (Maybe an hour?)
We should be careful to make these limits apply to relays, but not
authorities. Authorities need to test a large number of relays every hour.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28511>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
More information about the tor-bugs
mailing list