Re: Q: GRANT ... WITH ADMIN on PG 17

Hi ,

Found this interesting :
"gm-dbo" can manage membership in "gm-doctors" (ADMIN TRUE), but does not inherit
the role's privileges, nor can "gm-dbo" assume the identity of "gm-doctors".

INHERIT option should be used in caution to reduce the risk of privilege escalation, especially for sensitive roles:

*
Set NOINHERIT to TRUE on roles with elevated privileges (e.g., roles that have SUPERUSER, CREATEDB, CREATEROLE, or access to critical data or functions).
*
Tag such roles as sensitive, and prioritize restricting their inheritance to avoid unintended privilege propagation.
*
Enforce role separation by ensuring that users can manage sensitive roles without inheriting their privileges.

Thanks & Regards

Dinesh Nair

________________________________
From: Dominique Devienne <ddevienne(at)gmail(dot)com>
Sent: Monday, August 25, 2025 6:08 PM
To: Pavel Luzanov <p(dot)luzanov(at)postgrespro(dot)ru>
Cc: Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>; Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net>; pgsql-general(at)lists(dot)postgresql(dot)org <pgsql-general(at)lists(dot)postgresql(dot)org>
Subject: Re: Q: GRANT ... WITH ADMIN on PG 17

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On Mon, Aug 25, 2025 at 2:22 PM Pavel Luzanov <p(dot)luzanov(at)postgrespro(dot)ru> wrote:
>> On 22.08.2025 11:40, Laurenz Albe wrote:
>> Yes, that should work as follows: [...]

> [...] A safer option is to use security definer function to grant membership

FWIW, it's basically what I did.

My primary "admin" application role lost CREATEROLE,
and instead gained EXECUTE on security-definer procs
from a new lower-level role (with CREATEROLE),
in a new separate schema, which does all create/drop
roles or grant/revoke DDLs.

Which has the added benefits to enforce naming conventions for roles,
to enforce grants are only between our "per-DB" roles,
and made it easy to generate an audit-log for all those DDLs.

So the v16 ROLE changes created a BIG MESS for us,
slowing us down quite a bit, but we ended up with a much
better "v2" architecture, so it was not all a loss... YMMV.

So +1 to Pavel. --DD