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Date:      Mon, 18 Nov 1996 22:21:49 -0700 (MST)
From:      Marc Slemko <marcs@znep.com>
To:        Poul-Henning Kamp <phk@critter.tfs.com>
Cc:        freebsd-security@FreeBSD.org
Subject:   Re: BoS: Exploit for sendmail smtpd bug (ver. 8.7-8.8.2). 
Message-ID:  <Pine.BSF.3.95.961118220414.523B-100000@alive.ampr.ab.ca>
In-Reply-To: <9172.848302243@critter.tfs.com>

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All arguments about just how much of a MTA needs to bet setuid and why it
can/can't be that way in real/fake life, do people think what phk suggests
would be a useful thing, either as a seperate patch or in the base kernel? 

It is trivial to implement; took 10 minutes to hack together a limited
version (ie. uses names like net.inet.tcp.uidforport_25 because I didn't
feel like creating a new level just for my hack and all the ports aren't
implemented). 

The biggest problem I see to implementing such a thing is that I can't see
a pretty way to make it fit into the sysctl mold without having 1024
lines, one for each port < 1024.  Anyone have any ideas on how to do that
nicely or if 1024 lines is ok?

On Mon, 18 Nov 1996, Poul-Henning Kamp wrote:

> What we REALLY need, is a way for root, to hand out certain priviledges.
> 
> Imagine this:
> 
> 	sysctl -w net.inet.tcp.uidforport.25=`id -ur smtp`
> 	sysctl -w net.inet.tcp.uidforport.20=`id -ur ftp`
> 	sysctl -w net.inet.tcp.uidforport.21=`id -ur ftp`
> 	sysctl -w net.inet.tcp.uidforport.119=`id -ur nntp`
> 
> This means that users with UID smtp can bind to socket 25 (aka smtp),
> and so on.  Now sendmail NEVER needs to be root.
> 
> How's that for security ?




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