Re: RFC: Additional Directory for Extensions

On Mon, 24 Jun 2024 at 18:11, Nathan Bossart <nathandbossart@gmail.com> wrote:
> At first glance, the general idea seems reasonable to me.  I'm wondering
> whether there is a requirement for this directory to be prepended or if it
> could be appended to the end.  That way, the existing ones would take
> priority, which might be desirable from a security standpoint.

Citus does ship with some override library for pgoutput to make
logical replication/CDC work correctly with sharded tables. Right now
using this override library requires changing dynamic_library_path. It
would be nice if that wasn't necessary. But this is obviously a small
thing. And I definitely agree that there's a security angle to this as
well, but honestly that seems rather small too. If an attacker can put
shared libraries into the extension_destdir, I'm pretty sure you've
lost already, no matter if extension_destdir is prepended or appended
to the existing $libdir.