Re: Support tls-exporter as channel binding for TLSv1.3

On Tue, Sep 20, 2022 at 11:01 AM Jacob Champion <jchampion@timescale.com> wrote:
> Well, I'm working on a next version, but it's ballooning in complexity
> as I try to navigate the fix for OpenSSL 1.0.1 (which is currently
> failing the tests, unsurprisingly).

To be more specific: I think I'm hitting the case that Heikki pointed
out several years ago [1]:

> The problematic case is when e.g. the server
> only supports tls-unique and the client only supports
> tls-server-end-point. What we would (usually) like to happen, is to fall
> back to not using channel binding. But it's not clear how to make that
> work, and still protect from downgrade attacks.

The problem was deferred when tls-unique was removed. We might have to
actually solve it now.

bcc: Heikki, in case he would like to weigh in.

--Jacob

[1] https://www.postgresql.org/message-id/ec787074-2305-c6f4-86aa-6902f98485a4%40iki.fi