Path: utzoo!attcan!uunet!munnari.oz.au!labtam!timr
From: timr@labtam.oz (Tim Roper)
Newsgroups: comp.windows.x
Subject: Re: xterm is setuid - why? Dangerous?
Summary: of relevance to System V Release 3.2++ sites
Message-ID: <4182@labtam.oz>
Date: 7 Apr 90 13:00:38 GMT
References: <1990Apr5.005054.6999@melba.bby.oz.au> <272@roo.UUCP> <5068@crltrx.crl.dec.com>
Organization: Labtam Limited., Melbourne, Australia
Lines: 18

In article <5068@crltrx.crl.dec.com>, jg@crltrx.crl.dec.com (Jim Gettys) writes:
> ...
> It is setuid since there is no other way to guarantee that
> xterm can use the pseudo-tty it needs; it might have been
> left in an unusable state (i.e. owner and protection set wrong)
> by a previous program.
> ... 
When using the ptm/pts/ptem flavour of pseudo-terminals as implemented by
System V Release 3.2 (and later) and supported by the X.V11R4
xterm, xterm does not need to be set uid root for the above reason as
a separate set uid root program is run to take care of these things.

If you want /etc/utmp to be updated and don't want to make it world writable
you still need to have xterm set uid root.  There is probably an
argument for making it set gid sys (say) and making /etc/utmp group
sys, group writable.

-Tim.