Horton

Re: Possibility to disable `ALTER SYSTEM`

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Maciek Sakrejda <m.sakrejda@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Joel Jacobson <joel@compiler.org>, Andrew Dunstan <andrew@dunslane.net>, Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Magnus Hagander <magnus.hagander@redpill-linpro.com>, "daniel@yesql.se" <daniel@yesql.se>
Date: 2024-03-14T23:43:15Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add allow_alter_system GUC.

  2. Rename COMPAT_OPTIONS_CLIENT to COMPAT_OPTIONS_OTHER.

  3. Remove support for version-0 calling conventions.

On Thu, Mar 14, 2024 at 5:15 PM Maciek Sakrejda <m.sakrejda@gmail.com> wrote:
> It's not a security feature: it's a usability feature.
>
> It's a usability feature because, when Postgres configuration is
> managed by an outside mechanism (e.g., as in a Kubernetes
> environment), ALTER SYSTEM currently allows a superuser to make
> changes that appear to work, but may be discarded at some point in the
> future when that outside mechanism updates the config. They may also
> be represented incorrectly in a management dashboard if that dashboard
> is based on the values in the outside configuration mechanism, rather
> than values directly from Postgres.
>
> In this case, the end user with access to Postgres superuser
> privileges presumably also has access to the outside configuration
> mechanism. The goal is not to prevent them from changing settings, but
> to offer guard rails that prevent them from changing settings in a way
> that will be unstable (revertible by a future update) or confusing
> (not showing up in a management UI).
>
> There are challenges here in making sure this is _not_ seen as a
> security feature. But I do think the feature itself is sensible and
> worthwhile.

This is what I would have said if I'd tried to offer an explanation,
except you said it better than I would have done.

-- 
Robert Haas
EDB: http://www.enterprisedb.com