How can I drop privileges in Perl?

Question

I created a server program that will be started as root. After it is started I want to drop privileges to another user. How can I do this securely?

Answer 1

See Privileges::Drop.

Answer 2

You don't really need a module, although the one linked by Benji York looks pretty nice.

It's a simple matter of setting the UID via $< and $>. See perlvar for further information on these. You can also set the GID this way using $( and $); note that you need to set $) = "$target_gid $target_gid" if you want to drop supplemental groups. Don't forget to test for success afterwards.