From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andreas Joseph Krogh <andreas@visena.com>
cc: pgsql-general@lists.postgresql.org
Subject: Re: prevent users from SELECT-ing from pg_roles/pg_database
In-reply-to: <VisenaEmail.66.54f51e587b38c9cc.18fab4b4eb6@origo-test01.app.internal.visena.net>
References: <VisenaEmail.66.54f51e587b38c9cc.18fab4b4eb6@origo-test01.app.internal.visena.net>
Comments: In-reply-to Andreas Joseph Krogh <andreas@visena.com>
	message dated "Fri, 24 May 2024 17:51:59 +0200"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <671404.1716570133.1@sss.pgh.pa.us>
Date: Fri, 24 May 2024 13:02:13 -0400
Message-ID: <671405.1716570133@sss.pgh.pa.us>
Archived-At: <https://www.postgresql.org/message-id/671405.1716570133%40sss.pgh.pa.us>
Precedence: bulk

Andreas Joseph Krogh <andreas@visena.com> writes:
> Hi, is there a way to prevent a user/role from SELECT-ing from certain 
> system-tables?
> I'd like the contents of pg_{user,roles,database} to not be visible to all 
> users.

As noted, you can in principle revoke the public SELECT grant from
those views/catalogs.  However, the system is not designed to hide
such information, which means you'll have (at least) two kinds of
issues to worry about:

1. Queries or tools breaking that you didn't expect to break.
It's hardly uncommon for instance for queries on pg_class to
join to pg_roles to get the owner names for tables.

2. Information leaks.  For example, mapping role OID to role name
is trivial with either regrole or pg_get_userbyid(), so it
wouldn't take long to scan the plausible range of role OIDs and
get all their names, even without SQL access to the underlying
catalog.

			regards, tom lane