Bugs in the "at" command - fix

[bob at SU-SHASTA.ARPA]

The fix for making "at" secure under System III & System V is to do this:
	chmod 700 /usr/spool/at
	chown root /usr/spool/at
	chmod 4755 /usr/bin/at
If your cron doesn't run as root also do:
	chmod 4755 /usr/lib/atrun
	chown root /usr/lib/atrun

The several versions of "at" that I've seen all chown the spool file to the
real UID so it's safe to make it set-uid and also prevent one from reading
files that the real UID isn't allowed to.

Note that no source changes or re-compilation is required.

Bob Toxen
Silicon Graphics
ucbvax!Shasta!olympus!bob