Date: Thu, 21 Jul 2022 16:48:32 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Gurjeet Singh <gurjeet@singh.im>,
	Postgres Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Fwd: Unprivileged user can induce crash by using an SUSET param
 in PGOPTIONS
Message-ID: <20220721234832.GA3815415@nathanxps13>
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On Thu, Jul 21, 2022 at 07:30:20PM -0400, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> +    StartTransactionCommand();
>>      process_session_preload_libraries();
>> +    CommitTransactionCommand();
> 
> Yeah, that way would avoid any questions about changing the order of
> operations, but it seems like a mighty expensive solution: it's
> adding a transaction to each backend start on the off chance that
> (a) session_preload_libraries/local_preload_libraries is nonempty and
> (b) the loaded libraries are going to do anything where it'd matter.
> So that's why I thought of moving the call inside a pre-existing
> transaction.
> 
> If we had to back-patch this into any released versions, I'd agree with
> taking the performance hit in order to reduce the chance of side-effects.
> But I think as long as we only have to do it in v15, it's not too late to
> possibly cause some compatibility issues for extensions.

Yeah, fair point.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com