fine-grained sudoers configuration (allowed commandline arguments)

Question

is there a straight-forward way to allow a user to run (for example)

/usr/bin/pacman -S -u

as root, without allowing him to run

/usr/bin/pacman -S -u some_package

?

The line

user ALL=(root) NOPASSWD: /usr/bin/pacman -S -u

allows both, and

user ALL=(root) NOPASSWD: /usr/bin/pacman -S -u ""

appears to be semantically equivalent.

Answer 1

For your case try something like this:

Cmnd_Alias PACMAN = /usr/bin/pacman -S -u, ! /usr/bin/pacman -S -u some_package
user ALL=(root) NOPASSWD: PACMAN

You can use shell glob patterns like [a-z],[0-9],* etc. in your sudoers file to exclude packages that match a certain pattern.

Answer 2

Write a script that does what you want and give sudo access to it.

Also make sure that whatever environment this is run in does not have access to the networking at all, or they can just use their own dns to spoof the mirror and then run arbitrary code as root when it gets installed by pacman.