Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Tue, May 10, 2022 at 12:16 AM Euler Taveira <euler@eulerto.com> wrote:
> >
> > On Mon, May 9, 2022, at 11:09 AM, Antonin Houska wrote:
> >
> > Now that the user can specify rows and columns to be omitted from the logical
> > replication [1], I suppose hiding rows and columns from the subscriber is an
> > important use case. However, since the subscription connection user (i.e. the
> > user specified in the CREATE SUBSCRIPTION ... CONNECTION ... command) needs
> > SELECT permission on the replicated table (on the publication side), he can
> > just use another publication (which has different filters or no filters at
> > all) to get the supposedly-hidden data replicated.
> >
> > The required privileges were not relaxed on publisher after the row filter and
> > column list features. It is not just to "create another publication". Create
> > publications require CREATE privilege on databases (that is *not* granted to
> > PUBLIC).If you have an untrusted user that could bypass your rules about hidden
> > data, it is better to review your user privileges.
> >
>
> Also, to create a subscription (which combines multiple publications
> to bypass rules), a user must be a superuser. So, isn't that a
> sufficient guarantee that users shouldn't be able to bypass such
> rules?
My understanding is that the rows/columns filtering is a way for the
*publisher* to control which data is available to particular replica. From
this point of view, the publication privileges would just make the control
complete.
--
Antonin Houska
Web: https://www.cybertec-postgresql.com