Opened 19 months ago

Last modified 3 weeks ago

#24487 assigned defect

Reverse path selection (choose outer hops first)

Reported by: mikeperry Owned by: mikeperry
Priority: High Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: guard-discovery-prop247-controller, needs-proposal, 034-roadmap-subtask, 034-triage-20180328, 034-included-20180328
Cc: asn Actual Points:
Parent ID: #25546 Points:
Reviewer: asn Sponsor:


Because Tor's path selection chooses inner nodes first, and then excludes those nodes from being used in outer hops, over many circuits, outer hops get information about the choice of inner hops/guards.

We need to reverse the selection of nodes in the loop circuit_establish_circuit() in order to fix this.

This isn't as bad as it might otherwise be, because the last hop already is chosen first in that function. So it is a little tricky to take advantage of this info leak.

Child Tickets

Change History (14)

comment:1 Changed 19 months ago by mikeperry

Keywords: guard-discovery-prop247-controller added; guard-discovery removed

comment:2 Changed 19 months ago by mikeperry

Owner: set to mikeperry
Status: newassigned

comment:3 Changed 19 months ago by asn

Cc: asn added

comment:4 Changed 19 months ago by nickm

Keywords: needs-proposal added

comment:5 Changed 17 months ago by nickm

Milestone: Tor: 0.3.3.x-finalTor: 0.3.4.x-final

Mark a lot of assigned/needs_revision tickets as 0.3.4. If you think this should happen in 0.3.3 instead, just let me know?

comment:6 Changed 16 months ago by asn

Reviewer: asn

comment:7 Changed 15 months ago by asn

Parent ID: #9001#25546

comment:8 Changed 15 months ago by nickm

Keywords: 034-roadmap-subtask added

comment:9 Changed 15 months ago by nickm

Keywords: 034-triage-20180328 added

comment:10 Changed 15 months ago by nickm

Keywords: 034-included-20180328 added

comment:11 Changed 14 months ago by asn

Do we still want to do this, even tho we did #25705 for vanguard circs?

comment:12 Changed 14 months ago by mikeperry

Milestone: Tor: 0.3.4.x-finalTor: unspecified

I think we're still thinking about path restrictions for prop291. We may still want this... Otoh, I suppose we could close and then open new tickets for prop291 as needed.

comment:13 Changed 3 weeks ago by gaba

Removing sponsor V as we do not have more time to include this tickets in the sponsor.

comment:14 Changed 3 weeks ago by gaba

Sponsor: SponsorV-can

Removing sponsor from tickets that we do not have time to fit in the remain of this sponsorship.

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