From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nathan Bossart <nathandbossart@gmail.com>
cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, michael@paquier.xyz,
        gurjeet@singh.im, pgsql-hackers@postgresql.org
Subject: Re: Unprivileged user can induce crash by using an SUSET param in
 PGOPTIONS
In-reply-to: <20220722223359.GB3998906@nathanxps13>
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 <729330.1658516182@sss.pgh.pa.us> <20220722223359.GB3998906@nathanxps13>
Comments: In-reply-to Nathan Bossart <nathandbossart@gmail.com>
	message dated "Fri, 22 Jul 2022 15:33:59 -0700"
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Date: Fri, 22 Jul 2022 18:44:04 -0400
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Nathan Bossart <nathandbossart@gmail.com> writes:
> On Fri, Jul 22, 2022 at 02:56:22PM -0400, Tom Lane wrote:
>> +	if (!bootstrap &&
>> +		!IsAutoVacuumWorkerProcess() &&
>> +		!IsBackgroundWorker &&
>> +		!am_walsender)
>> +		process_session_preload_libraries();

> I worry that this will be easily missed when adding new types of
> non-interactive sessions, but I can't claim to have a better idea.

Yeah, that bothered me too.  A variant that I'd considered is to
create a local variable "bool interactive" and set it properly
in each of the arms of the if-chain dealing with authentication
(starting about postinit.c:800).  While that approach would cover
most of the tests shown above, it would not have exposed the issue
of needing to check am_walsender, so I'm not very convinced that
it'd be any better.

Another idea is to add a "bool interactive" parameter to InitPostgres,
thereby shoving the issue out to the call sites.  Still wouldn't
expose the am_walsender angle, but conceivably it'd be more
future-proof anyway?

			regards, tom lane