bug#61709: [PATCH] Security hardening: safely invoke `shell-command*' function.

[Eli Zaretskii]

> From: lux <lx@shellcodes.org>
> Cc: 61709@debbugs.gnu.org
> Date: Thu, 23 Feb 2023 21:17:12 +0800
> 
> You're right, thank you. I rewrited this patch.
> 
> Let me briefly explain this patch:
> 
> 1. I think `filesets-select-command' not need fixed, because it not
> used, and I cleaned up relevant old comments in `filesets-external-
> viewers'.
> 
> 2. Using `shell-quote-argument' to replace `filesets-quote' and
> `(format "%S" ...)'. Because in the shell, double quotation marks can
> still execute unexpected code, such as $(), `command` and $var.

Thanks.  I hesitate installing this because I don't myself use
filesets, and we don't have tests for it.  So I'm not sure how to
ensure that we don't break this package.

Does someone else here use filesets?