Re: [HACKERS] Password identifiers, protocol aging and SCRAM protocol

On Fri, Dec 9, 2016 at 5:11 PM, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> Couple of things I should write down before I forget:
>
> 1. It's a bit cumbersome that the scram verifiers stored in
> pg_authid.rolpassword don't have any clear indication that they're scram
> verifiers. MD5 hashes are readily identifiable by the "md5" prefix. I think
> we should use a "scram-sha-256:" for scram verifiers.

scram-sha-256 would make the most sense to me.

> Actually, I think it'd be awfully nice to also prefix plaintext passwords
> with "plain:", but I'm not sure it's worth breaking the compatibility, if
> there are tools out there that peek into rolpassword. Thoughts?

pgbouncer is the only thing coming up in mind. It looks at pg_shadow
for password values. pg_dump'ing data from pre-10 instances will also
need to adapt. I see tricky the compatibility with the exiting CREATE
USER PASSWORD command though, so I am wondering if that's worth the
complication.

> 2. It's currently not possible to use the plaintext "password"
> authentication method, for a user that has a SCRAM verifier in rolpassword.
> That seems like an oversight. We can't do MD5 authentication with a SCRAM
> verifier, but "password" we could.

Yeah, that should be possible...
-- 
Michael