At Wed, 08 Jun 2022 12:09:27 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in
> At Wed, 08 Jun 2022 04:38:02 +0200, Laurenz Albe <laurenz.albe@cybertec.at> wrote in
> > If anything, it should be done in the FDW, because it is only necessary if the
> > FDW calls the remote site during planning.
> >
> > The question is: is this a bug in postgres_fdw that should be fixed?
>
> It's depends on what we think about allowing remote access trials
> through unprivileged foreign table in any style. It won't be a
> problem if the system is configured appropriately but too-frequent
> estimate accesses via unprivileged foreign tables might be regarded as
> an attack attempt.
In other words, I don't think it's not a bug and no need to fix. If
one want to prevent such estimate accesses via unprivileged foreign
tables, it is enough to prevent non-privileged users from having a
user mapping. This might be worth documenting?
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center