Setuid binaries and File Ownerships in FreeBSD9.0

[Robert Bonomi]

> From: Martin McCormick <martin at dc.cis.okstate.edu>
> To: FreeBSD Questions <freebsd-questions at freebsd.org>
> Subject: Setuid binaries and File Ownerships in FreeBSD9.0
> Date: Wed, 23 Jan 2013 14:26:16 -0600
>

[[..  sneck  ..]]

> 	When the application first runs, it gets the UID and GID
> of the user and uses 
>
> setuid(heruid); and setgid(hergid); to temporarily downgrade and
> those files are owned by the right user but setuid(0); doesn't
> appear to upgrade back to root.
>
> 	Is there any other strategy that gets one back to root
> short of using chown and then a system call and never
> downgrading privilege?

man setEuid