Opened 7 years ago

Closed 6 years ago

Last modified 6 years ago

#6135 closed enhancement (fixed)

Tune + tighten path bias parameters

Reported by: mikeperry Owned by:
Priority: High Milestone: Tor: 0.2.4.x-final
Component: Core Tor/Tor Version:
Severity: Keywords: needs-proposal MikePerry201210d tor-client
Cc: nickm, arma Actual Points: 28
Parent ID: #5456 Points:
Reviewer: Sponsor:

Description

The path bias defenses in #5458 and #5956 will have tunable parameters to allow us to dial in on the lowest acceptable amount of bias while not also breaking stuff.

That is going to require more work and attention, though. It's possible that network scanners (ie #5459) can provide us with answers for #5458.

We can also ask our volunteer QA team to report what sorts of values they see in their logs for stuff like this, to get an idea on real ranges in real clients.

Child Tickets

Change History (10)

comment:1 Changed 7 years ago by mikeperry

Cc: nickm arma added

Ok, I did some work to get closer to a solution here. See
https://gitweb.torproject.org/torflow.git/tree/HEAD:/CircuitAnalysis/PathBias. In particular,
https://gitweb.torproject.org/torflow.git/blob/HEAD:/CircuitAnalysis/PathBias/observations.txt and
https://gitweb.torproject.org/torflow.git/blob_plain/HEAD:/CircuitAnalysis/PathBias/results.txt

Here's the 4 line summary:

  1. Parameter choice is blocked on getting a good measure of the ambient success rate.
  2. We should transform PATH_BIAS_SCALE_FACTOR into a percent, and make it high. Like 95.
  3. We might want to use a separate, lower PATH_BIAS_PCT before SCALE_THRESHOLD.
  4. After SCALE_THRESHOLD, PATH_BIAS_PCT can be pretty high for notice and warn

comment:2 Changed 7 years ago by nickm

Milestone: Tor: 0.2.4.x-final

comment:3 Changed 7 years ago by mikeperry

Keywords: proposal-needed added

comment:4 Changed 7 years ago by mikeperry

Keywords: MikePerry201210 added

comment:5 Changed 7 years ago by mikeperry

Keywords: MikePerry201210d added; MikePerry201210 removed

comment:6 Changed 7 years ago by nickm

Keywords: needs-proposal added; proposal-needed removed

comment:7 Changed 7 years ago by nickm

Keywords: tor-client added

comment:8 Changed 7 years ago by nickm

Component: Tor ClientTor

comment:9 Changed 6 years ago by mikeperry

Actual Points: 28
Resolution: fixed
Status: newclosed

I'm going to call this done by virtue of the proposal being written and the live scan + analysis I performed to decide values for "normal" operation. We do have more work to do for the path bias code, though. See #7157 and #7281.

comment:10 Changed 6 years ago by mikeperry

Parent ID: #5456
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