Re: bytea(uuid) missing proleakproof?

> On Jun 22, 2026, at 11:59, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:
>
> Hi,
>
> While testing "[ba21f5bf8] Allow explicit casting between bytea and uuid", I noticed that the new proc bytea(uuid) is not marked as proleakproof, while the other functions in the group, bytea(int2), bytea(int4), and bytea(int8), are all marked as proleakproof.
>
> Looking into the backend function uuid_bytea(), it just returns uuid_send(fcinfo). For a valid uuid datum, uuid_send() only copies the UUID value into a bytea result, so I don't see an input-dependent error path or other reason not to mark bytea(uuid) as proleakproof.
>
> This matters for security barrier planning, because a qual using uuid::bytea is otherwise treated as leaky and cannot be pushed down. Attached is a tiny patch to fix that.
>
> I didn't mark uuid_send() itself as proleakproof because none of send/receive functions are marked as proleakproof in pg_proc.dat.
>
> Best regards,
> --
> Chao Li (Evan)
> HighGo Software Co., Ltd.
> https://www.highgo.com/
>
>
>
>
> <v1-0001-Mark-uuid-to-bytea-cast-as-leakproof.patch>

I just added this to the v19 open item list. Please feel free to reject it if it’s not considered an issue.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/