Re: Incorrect allocation handling for cryptohash functions with OpenSSL

From: Heikki Linnakangas <hlinnaka(at)iki(dot)fi>
To: Michael Paquier <michael(at)paquier(dot)xyz>, Postgres hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Incorrect allocation handling for cryptohash functions with OpenSSL
Date: 2020-12-18 09:35:14
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On 18/12/2020 09:35, Michael Paquier wrote:
> Hi all,
> As of the work done in 87ae9691, I have played with error injections
> in the code paths using this code, but forgot to count for cases where
> cascading resowner cleanups are involved. Like other resources (JIT,
> DSM, etc.), this requires an allocation in TopMemoryContext to make
> sure that nothing gets forgotten or cleaned up on the way until the
> resowner that did the cryptohash allocation is handled.
> Attached is a small extension I have played with by doing some error
> injections, and a patch. If there are no objections, I would like to
> commit this fix.

pg_cryptohash_create() is now susceptible to leaking memory in
TopMemoryContext, if the allocations fail. I think the attached should
fix it (but I haven't tested it at all).

BTW, looking at pg_cryptohash_ctx and pg_cryptohash_state, why do we
need two structs? They're both allocated and controlled by the
cryptohash implementation. It would seem simpler to have just one.

- Heikki

Attachment Content-Type Size
cryptohash-leaks.patch text/x-patch 1.0 KB

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