search

tlswg / tls13-spec

TLS 1.3 Specification
565 stars 157 forks source link

Forbid the sender from sending duplicate supported groups entries. #1354

Closed bob-beck closed 2 months ago

bob-beck commented 4 months ago

Supported Groups is intimately tied to Key Share, where Key Share must be sent in the preference order specified by Supported Groups.

Duplicate Key Shares for a group are already forbidden from being sent, but allowing duplicates in Supported Groups makes this a bit muddled if supported groups is permitted to be, for example, ABA and the client sends key share B then A.

Now, nothing sane should actually be sending duplicate supported groups in a preference order, but it's still not forbidden to do so today. I'm suggesting we just not allow this so server side implementations can reject attempts to do so.

ekr commented 4 months ago

This seems reasonable, but it's a normative change, so the chairs need to tell us how to proceed.

@seanturner @jsalowey @dconnolly

ekr commented 3 months ago

@seanturner @jsalowey @dconnolly do the chairs want to entertain this?

seanturner commented 2 months ago

@ekr this PR is ready to merge; see mail.