From owner-freebsd-hackers  Sun Feb  9 09:25:24 1997
Return-Path: <owner-hackers>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id JAA24833
          for hackers-outgoing; Sun, 9 Feb 1997 09:25:24 -0800 (PST)
Received: from news1.gtn.com (news1.gtn.com [194.77.0.15])
          by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id JAA24828;
          Sun, 9 Feb 1997 09:25:21 -0800 (PST)
Received: (from uucp@localhost) by news1.gtn.com (8.7.2/8.7.2) with UUCP id SAA13068; Sun, 9 Feb 1997 18:15:36 +0100 (MET)
Received: (from andreas@localhost) by klemm.gtn.com (8.8.5/8.8.2) id RAA02064; Sun, 9 Feb 1997 17:16:49 +0100 (MET)
Message-ID: <19970209171649.EU26961@klemm.gtn.com>
Date: Sun, 9 Feb 1997 17:16:49 +0100
From: andreas@klemm.gtn.com (Andreas Klemm)
To: davidn@labs.usn.blaze.net.au (David Nugent)
Cc: freebsd-hackers@freebsd.org, current@freebsd.org
Subject: Re: should permissions of /usr/bin/login be changed to 0100 ???
References: <19970208135454.ZJ37734@klemm.gtn.com> <19970210010326.55168@usn.blaze.net.au>
X-Mailer: Mutt 0.60-PL0
Mime-Version: 1.0
In-Reply-To: <19970210010326.55168@usn.blaze.net.au>; from "David Nugent" on Feb 10, 1997 01:03:26 +1100
Sender: owner-hackers@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

David Nugent writes:
> On Feb 02, 1997 at 01:54:54PM, Andreas Klemm wrote:
> > >From the OPIE README file:
> > [...]
> >         While an almost universal "feature", most people remain unaware that
> > an intruder can log into a system, then log in again by running the "login"
> > command from a shell. Because the second login is from the local host, the
> > utmp entry will not show a remote login host anymore. The OPIE replacement
> > for /bin/login currently carries on this behavior for compatibility reasons.
> 
> Compatibility that is broken, imho. It breaks wtmp (and therefore
> last(1)), for example, by having a login record (the original) with
> no logout record.
> 
> 
> > If you would like to prevent this from happening, you should change the
> > permissions of /bin/login to 0100, thus preventing unprivileged users from
> > executing it. This fix should work on non-OPIE /bin/login programs as well.
> 
> Actually, imho, NO user should be able to execute it. login should
> not be setuid. I see no functionality that su(1) doesn't already
> take care of.
> 
> 
> > Our /usr/bin/login program has the following permissions:
> > -r-sr-xr-x  1 root  bin  24576  6 Feb 01:28 /usr/bin/login
> > 
> > Would it be useful to change permissions to 0100 ?
> 
> Just removing the setuid bit makes it harmless, but 0100 will
> prevent anyone but root trying, anyway. I'm all for it.

So would it be ok, to install "login" with 0100 permissions ? If
nobody is against it, I'd do the change in -current.

Wouldn't that be additionally something for 2.2 and 2.1.7 ?
After the whole security debate ?!

-- 
andreas@klemm.gtn.com         /\/\___      Wiechers & Partner Datentechnik GmbH
   Andreas Klemm          ___/\/\/         Support Unix -- andreas.klemm@wup.de
pgp p-key  http://www-swiss.ai.mit.edu/~bal/pks-toplev.html  >>> powered by <<<
ftp://sunsite.unc.edu/pub/Linux/system/Printing/aps-491.tgz  >>>    FreeBSD <<<