Re: RFC: Non-user-resettable SET SESSION AUTHORISATION

Bruce Momjian wrote:
> On Sun, May 17, 2015 at 09:31:47PM +0200, José Luis Tallón wrote:
> > On 05/17/2015 07:39 PM, Tom Lane wrote:
> > >=?windows-1252?Q?Jos=E9_Luis_Tall=F3n?= <jltallon(at)adv-solutions(dot)net> writes:
> > >>On the other hand, ISTM that what we all intend to achieve is some
> > >>Postgres equivalent of the SUID bit... so why not just do something
> > >>equivalent?
> > >>-------
> > >> LOGIN -- as user with the appropriate role membership / privilege?
> > >> ...
> > >> SET ROLE / SET SESSION AUTHORIZATION WITH COOKIE / IMPERSONATE
> > >> ... do whatever ... -- unprivileged user can NOT do the
> > >>"impersonate" thing
> > >> DISCARD ALL -- implicitly restore previous authz
> > >>-------
> > >Oh? What stops the unprivileged user from doing DISCARD ALL?
> >
> > Indeed. The pooler would need to block this.
> > Or we would need to invent another (this time, privileged) verb in
> > order to restore authz.
>
> What if you put the SQL in a function then call the function? I don't
> see how the pooler could block this.

I think the idea of having SET SESSION AUTH pass a cookie, and only let
RESET SESSION AUTH work when the same cookie is supplied, is pretty
reasonable.

--
Álvaro Herrera http://www.2ndQuadrant.com/
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