From: Jonathan Nielsen <jonathan@...>
Date: 2010-04-05T01:08:44+09:00
Subject: Re: $SAFE=0 for setuid?

> From most documentation I see that $SAFE is automatically set to 1 if
> you run ruby as root.

Not entirely true, it sets $SAFE to 1 if you run it with setuid, but
just running as root $SAFE will still be 0.

> I need $SAFE=0 for pcap to function, however I also need to run it with
> root privileges for it to function, but as soon as setuid is used, $SAFE
> changes to 1.
>
> Is there a way to have the safety level be overridden to 0 with setuid
> active? Otherwise I don't see how a library like pcap can be used.

If you need to run it setuid, I found some C code that claims to be
able to do this (with lots and lots of warnings that it's a bad idea
and could damage your system) here:
http://www.justskins.com/forums/setuid-wrapper-71480.html

And yeah, it really is a bad idea to use that code... terribly
insecure.  Just execute it as root with sudo or su unless you REALLY
need setuid.

-Jonathan Nielsen