Horton

Re: Possibility to disable `ALTER SYSTEM`

Daniel Gustafsson <daniel@yesql.se>

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From: Daniel Gustafsson <daniel@yesql.se>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Jelte Fennema-Nio <postgres@jeltef.nl>, Bruce Momjian <bruce@momjian.us>, Joel Jacobson <joel@compiler.org>, Andrew Dunstan <andrew@dunslane.net>, Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>, Magnus Hagander <magnus.hagander@redpill-linpro.com>, Maciek Sakrejda <m.sakrejda@gmail.com>, Robert Haas <robertmhaas@gmail.com>
Date: 2024-03-19T17:57:10Z
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 19 Mar 2024, at 15:51, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 
> Heikki Linnakangas <hlinnaka@iki.fi> writes:
>> Perhaps we could make that even better with a GUC though. I propose a 
>> GUC called 'configuration_managed_externally = true / false". If you set 
>> it to true, we prevent ALTER SYSTEM and make the error message more 
>> definitive:
> 
>> postgres=# ALTER SYSTEM SET wal_level TO minimal;
>> ERROR:  configuration is managed externally
> 
>> As a bonus, if that GUC is set, we could even check at server startup 
>> that all the configuration files are not writable by the postgres user, 
>> and print a warning or refuse to start up if they are.
> 
> I like this idea.  The "bonus" is not optional though, because
> setting the files' ownership/permissions is the only way to be
> sure that the prohibition is even a little bit bulletproof.

Agreed, assuming we can solve the below..

> One small issue: how do we make that work on Windows?  Have recent
> versions grown anything that looks like real file permissions?

--
Daniel Gustafsson