Opened 2 years ago

Last modified 4 months ago

#22251 new enhancement

Spec should change: stop requiring Tor relays to support old link versions

Reported by: arma Owned by:
Priority: Medium Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: 032-unreached
Cc: ishbir@… Actual Points:
Parent ID: #9476 Points:
Reviewer: Sponsor:

Description (last modified by arma)

In our spec, we have

   All new relay implementations of the Tor protocol MUST support
   backwards-compatible renegotiation

But the v3 link handshake came out in Tor 0.2.3.6-alpha. That's certainly older than any relays. Is it older than any clients that we expect to work?

Step 0 in phasing out old link versions would be to admit in tor-spec that supporting them is not a MUST. I'd say we're ready to do this one any time. We could put v3 as the minimum you MUST implement, or we might pick v4, since it came out in 0.2.4.11-alpha, and that's pretty old now too.

Step 1 in phasing out old link versions would be to actually remove the code from mainline Tor. That's #9476.

Child Tickets

Change History (9)

comment:1 Changed 2 years ago by Insolsence

Cc: ishbir@… added

comment:2 Changed 2 years ago by yawning

Depends on #9476, though I'm not sure how much is left to do there.

comment:3 Changed 2 years ago by nickm

Agreed that a spec patch comes first, and then comes testing of what happens when old Tors hit the new behavior.

comment:4 Changed 2 years ago by arma

Description: modified (diff)
Summary: Time to retire old link versions?Time to not require Tor relays to support old link versions?

In light of #9476, I'm going to change this ticket to be only about the spec change.

comment:5 in reply to:  description Changed 2 years ago by teor

Replying to arma:

... the v3 link handshake came out in Tor 0.2.3.6-alpha. That's certainly older than any relays. Is it older than any clients that we expect to work?

We don't expect clients older than 0.2.4.26 or 0.2.5.11 to work: they don't believe enough current directory authority identities.

arma and I did the exact analysis by email the last time we dropped a directory authority, then posted it to tor-project:

Constraint 6: Tor versions before 0.2.8.1-alpha don't believe in
dannenberg's current v3 identity key, and Tor versions before 0.2.4.26
or 0.2.5.11 don't believe in longclaw at all. The dannenberg issue can
be solved by having dannenberg resume voting with its legacy v3 identity
key (I don't know why it stopped -- maybe it never started?), and the
longclaw issue can be solved by declaring that versions that old don't
matter to us.

https://lists.torproject.org/pipermail/tor-project/2016-July/000491.html

So we can declare v4 the only required version, if we like.

Last edited 2 years ago by teor (previous) (diff)

comment:6 Changed 2 years ago by nickm

Keywords: 032-unreached added
Milestone: Tor: 0.3.2.x-finalTor: unspecified

Mark a large number of tickets that I do not think we will do for 0.3.2.

comment:7 Changed 22 months ago by teor

Keywords: added
Parent ID: #9476

comment:8 Changed 22 months ago by teor

Keywords: removed

comment:9 Changed 4 months ago by arma

Summary: Time to not require Tor relays to support old link versions?Spec should change: stop requiring Tor relays to support old link versions

We have a potential fast zombie problem blocking us from ripping out the actual code (though that ship might have sailed some years ago), but in any case we could, any time we like, change the spec to say that relays don't need to support the old design.

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