Re: replacing role-level NOINHERIT with a grant-level option

On Thu, Jun 2, 2022 at 2:07 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
> I think we should also consider replacing role attributes with predefined
> roles.  I'm not sure that this proposal totally prepares us for such a
> change, given role attributes apply only to the specific role for which
> they are set and aren't inherited.  ISTM in order to support that, we'd
> need even more enhanced functionality.  For example, if I want 'robert' to
> be a superuser, and I want 'joe' to inherit the privileges of 'robert' but
> not 'pg_superuser', you'd need some way to specify inheriting only certain
> privileges possessed by an intermediate role.

I guess we could think about adding something like an ONLY clause,
like GRANT ONLY robert TO joe. I feel a little bit uncomfortable about
that, though, because it assumes that robert is a superuser but his
own privileges are distinguishable from those of the superuser. Are
they really? If I can assume robert's identity, I can presumably
Trojan my way into the superuser account pretty easily. I'll just
define a little trigger on one of his tables. I don't really see a way
where we can ever make it safe to grant a non-superuser membership in
a superuser role.

But even if there is a way, I think that is a separate patch from what
I'm proposing here. [NO]INHERIT only has to do with what privileges
you can exercise without SET ROLE. To solve the problem you're talking
about here, you'd need a way to control what privileges are conferred
in any manner, which is related, but different.

-- 
Robert Haas
EDB: http://www.enterprisedb.com