[tor-bugs] #5458 [Tor Client]: Clients should warn and disable guards responsible for excessive circuit failures
Tor Bug Tracker & Wiki
torproject-admin at torproject.org
Wed Jun 6 22:22:07 UTC 2012
#5458: Clients should warn and disable guards responsible for excessive circuit
failures
-----------------------------+----------------------------------------------
Reporter: mikeperry | Owner: mikeperry
Type: defect | Status: needs_review
Priority: major | Milestone: Tor: 0.2.3.x-final
Component: Tor Client | Version:
Keywords: MikePerry201206 | Parent: #5456
Points: 6 | Actualpoints:
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Changes (by nickm):
* status: needs_revision => needs_review
Comment:
I pushed a "bug5458" to my repository that handles all of my issues above
other than:
* A four-hop circuit IMO doesn't need special treatment. A cannibalized
circuit, though, will get counted as having succeeded twice, which isn't
necessarily what we want. This could throw off results if a large enough
fraction of circuits gets cannibalized.
* Is it possible to have PATH_BIAS_MIN_CIRCS on a guard all in progress
at once? If so, there might be an annoying problem when starting up a new
guard.
* We should do the math to see how successful the attack can be under
different parameter choices. (Under the current parameter choices, it
seems like you can do route capture pretty darn effectively so long as you
treat each new client honestly for a sufficiently large number of circuits
before doing the attack.)
* We should figure out what kind of false positive rate we expect, and
document that, and maybe even mention it in the warning. (A tiny but not
vanishing false positive rate, multiplied by a very large number of users
and a lot of time, means that we should expect some number of spurious
reports.)
Totally untested! Needs review. Also:
* Needs a path-spec.txt writeup.
* Needs a changes file.
* Needs to have the new parameters noted in dir-spec.
Also Mike Perry owes me a tasty beverage, to be added to the innumerable
tally of tasty beverages that Mike and I owe one another. And if the
ratio of beverages ordered to bevereges enjoyed becomes too high, we need
to move to another restaurant.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5458#comment:22>
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