Re: WIP: SCRAM authentication

On Mon, Nov 16, 2015 at 10:53 PM, Michael Paquier wrote:
> Reviving an old thread for a patch still registered in this commit
> fest to make the arguing move on.
>
> Supporting multiple verifiers for a single role has IMO clear advantages:
> - help transition to new protocols and decommission of old protocols
> without the need to create alternative roles in the backend when
> switching from one or the other.
> - move on to a more complex password aging system. The patch currently
> submitted allows only one verifier per type and per role so this is
> not a complete system. Still, the new catalog table pg_auth_verifiers
> could be later easily extended based on other aging properties that we
> consider adapted to reach this goal.
>
> There are clear concerns about protocol aging and how to facilitate
> the life of users to switch to a new system. Hence, I think that the
> patch could include the following:
> - A compatibility GUC allowed_password_verifiers defaulting to a list
> of verifier protocols that we think are safe. This would be added in
> the patch adding infrastructure for multiple verifiers, with default
> to md5. In the patch adding SCRAM, the value of this parameter is
> changed to md5,scram. If a user create a password verifier with a
> protocol not listed in this parameter we return to him a WARNING.
> ERROR may be too much but opinions are welcome.
> - A superuser cleanup function for pg_auth_verifiers aimed at being
> used by pg_upgrade to do needed cleanup of this catalog based on the
> previous GUC to remove outdated verifiers. Optionally, we could have
> an argument for a list of protocols to clean up.
> Using both things we could leverage the upgrade experience and
> transition between systems. Say even if at some point we decide to
> decommission SCRAM we could reuse the same infrastructure to move on
> to a new major version.
>
> Thoughts?

I am going to mark this patch as returned with feedback because of a
visible lack of interest. It would be nice if I could get some
feedback about the suggestions above to help move on for (why not) a
patch aiming for January's CF.
--
Michael