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Date:      Mon, 1 Nov 1999 14:36:32 +1100
From:      Peter Jeremy <jeremyp@gsmx07.alcatel.com.au>
To:        Spidey <beaupran@iro.umontreal.ca>
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: Examining FBSD set[ug]ids and their use
Message-ID:  <99Nov1.143118est.40332@border.alcanet.com.au>
In-Reply-To: <14364.64172.638014.558487@anarcat.dyndns.org>
References:  <14364.64172.638014.558487@anarcat.dyndns.org>

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On 1999-Nov-01 13:27:56 +1100, Spidey wrote:
>I started 'compiling' some info about the use of the setuid and setgid 
>files in FreeBSD.

An excellent idea.  Note that some of the files you specify are
ports.

As a general rule, anything that is setgid kmem should be converted
to a new sysctl with an unprivileged task to access it.

># Allow users to see processes?  Users cannot see the 'STARTED' and
># 'TIME' columns, from ps aux... I don't want to dig much more..
>	ps gname=kmem mode=2555

I believe it's necessary for users to see other users' processes.
The information should probably be available via /proc instead.

># I don't have a ccd... I can't test this.
>	ccdconfig gname=kmem

Probably unnecessary.  No-one but root needs to be able to run ccdconfig.

># Allow users to dump on remote (see dump(1), the BUGS section)
>	dump gname=tty
>	rdump gname=tty
>	restore gname=tty
>	rrestore gname=tty

As I recall it, this is to allow dump/restore to write to the console
(and wake up the operator) when it needs feeding.

># Allow users to bind on a socket (which? where?)
>	ping mode=4555
Needed to allow ordinary mortals to sent raw IP (ICMP) packets.

># Allow users to consult routing tables
>	route mode=4555

Needed to allow ordinary mortals to access the routing socket.
This is probably another sysctl candidate.

># ????? Look what's here?!
>			Xwrapper mode=4711

This is a wrapper for the X-server.  The idea is that Xwrapper is
slightly smaller :-) and less subject to security holes.

># Allow users to read master.passwd, skeykeys and probably other
># things...
>		login

Necessary to allow users to log in as another user.

># Allow users to read the mail queue
># Again, this is part of the sendmail suite and _can_ be replaced :)
>		mailq

Hard link to newaliases and sendmail.  Only needs root for local
mail delivery in the absence of a setuid local delivery agent.
(It's fairly trivial to sandbox sendmail).

># Allow users to use the catman cache
                  ^^^ update
>		man uname=man

># Allow users to 'read' /etc/master.passwd
>		su
Actually it's to allow users to change thir uid.

># I never understood what uucp was....
>/set mode=4555 uname=uucp gname=wheel
>		uucp
>		uuname
>		uustat gname=dialer mode=6555
>		uux

UUCP lives in it's own sandbox.

># "Gaming" management
>		dm

All games live in their own group for sandboxing.

># This is the sendmail super-program that does everything. Get rid of
># it, install postfix.. :)
Religious comments don't belong in a file being touted as a part
of generic FreeBSD.

Peter


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