Re: GNU screen buffer overflow

[Casper Dik <casper () holland sun com>]

> On Mon, 1 Dec 2003, Kyle Sallee wrote:
>
> > > With devpts and libutempter it is possible to install fully functional
> > > screen without suid/sgid.
> >
> > Does that mean any program that links with libutempter gains
> > complete suid/sgid root functionality, or only when executing 
> > the functions in the libutempter library, please?
>
> This means you do not need setuid root because devpts sets up the slave
> pty owner and group automatically and you do not need direct access to
> utmp/wtmp, e.g. via setgid utmp, because libtempter functions call an
> external setgid utmp helper called utempter to modify those files (the
> calling process is required to hold a corresponding master pty).


Nearly exactly like in generic SVR4 where ptys are setup using
/usr/lib/pt_chmod; and in Solaris there's the additional "utmp_update"
programs which allows you to set utmp entries; this is all hidden behind the
libc routines.

Casper