Re: ALTER ROLE/DATABASE RESET ALL versus security

Bruce Momjian wrote:
> Alvaro Herrera wrote:
> > Tom Lane wrote:
> > > Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > > > Tom Lane wrote:
> > > >> It looks to me like the code in AlterSetting() will allow an ordinary
> > > >> user to blow away all settings for himself. Even those that are for
> > > >> SUSET variables and were presumably set for him by a superuser. Isn't
> > > >> this a security hole? I would expect that an unprivileged user should
> > > >> not be able to change such settings, not even to the extent of
> > > >> reverting to the installation-wide default.
> > >
> > > > Yes, it is, but this is not a new hole. This works just fine in 8.4
> > > > too:
> > >
> > > So I'd argue for changing it in 8.4 too.
> >
> > Understood. I'm starting to look at what this requires.
>
> Any progress on this?

I have come up with the attached patch. I haven't tested it fully yet,
and I need to backport it. The gist of it is: we can't simply remove
the pg_db_role_setting tuple, we need to ask GUC to reset the settings
array, for which it checks superuser-ness on each setting.

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support