Re: Fix search_path for all maintenance commands

On Thu, 2023-07-06 at 18:39 -0700, Jeff Davis wrote:

> * The fix might not go far enough or might be in the wrong place. I'm
> open to suggestion here, too. Maybe we can make it part of the
> general
> function call mechanism, and can be overridden by explicitly setting
> the function search path? Or maybe we need new syntax where the
> function can acquire the search path from the session explicitly, but
> uses a safe search path by default?

I'm inclined to proceed with the current approach here, which is to
just fix search_path for maintenance commands. Other approaches may be
possible, but:

(a) We already special-case the way functions are executed for
maintenance commands in other ways -- we run the functions as the table
owner (even SECURITY INVOKER functions) and run them as a
SECURITY_RESTRICTED_OPERATION. Setting the search_path to a safe value
seems like a natural extension of that; and

(b) The lack of a safe search path is blocking other useful features,
such as the MAINTAIN privilege; and

(c) I don't see other proposals, aside from a few ideas I put forward
here[1], which didn't get any responses.

The current approach seemed to get support from Noah, Nathan, and Greg
Stark.

Concerns were raised by Gurjeet, Tom, and Robert in the 16 cycle; but
I'm not sure whether those objections were specific to the 16 cycle or
whether they are objections to the approach entirely. Comments?

Regards,
Jeff Davis

[1]
https://www.postgresql.org/message-id/6781cc79580c464a63fc0a1343637ed2b2b0cf09.camel%40j-davis.com