ppp-on is only root executable despite permissions

[Carl Lowenstein]

> Date: Fri, 21 Jul 2000 09:08:38 -0700
> From: "Michael O'Keefe" <mokeefe at qualcomm.com>
> Organization: Qualcomm Incorporated
> To: kplug-list at kernel-panic.org
> Subject: Re: ppp-on is only root executable despite permissions
>
> > there is yet another way: group permissions
> > 
> > pick some group that seems approprite, i shall use ``dialout''
> > 
> > # chgrp dialout `which pppd`
> > # chmod 4550 `which pppd`
> > 
> > now edit /etc/groups to make sure that ralph is in group dialout, and
> > mike is not.
> > 
> > mike cannot execute pppd, but ralph can - thanks to the non-world
> > executability of pppd, but since ralph can, and pppd is suid root, pppd
> > can do all the happy things it needs to.
> > 
> > UNIX at its best
>
> And ppl say Unix doesn't have ACL's !!!

It's a very coarse-grained ACL.  And I was wrong a couple of minutes ago,
4550 (set UID) is the correct thing.  The program has root privileges,
but only root and members of group 'dialout' can execute it.

    carl