Re: RFC: Additional Directory for Extensions

On Apr 3, 2024, at 8:54 AM, David E. Wheeler <david(at)justatheory(dot)com> wrote:

> Yes, I like the suggestion to make it require a restart, which lets the sysadmin control it and not limited to whatever the person who compiled it thought would make sense.

Here’s a revision of the Debian patch that requires a server start.

However, in studying the patch, it appears that the `extension_directory` is searched for *all* shared libraries, not just those being loaded for an extension. Am I reading the `expand_dynamic_library_name()` function right?

If so, this seems like a good way for a bad actor to muck with things, by putting an exploited libpgtypes library into the extension directory, where it would be loaded in preference to the core libpgtypes library, if they couldn’t exploit the original.

I’m thinking it would be better to have the dynamic library lookup for extension libraries (and LOAD libraries?) separate, so that the `extension_directory` would not be used for core libraries.

This would also allow the lookup of extension libraries prefixed by the directory field from the control file, which would enable much tidier extension installation: The control file, SQL scripts, and DSOs could all be in a single directory for an extension.

Thoughts?

Best,

David