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Date:      Thu, 27 Mar 1997 13:41:03 -0600 (CST)
From:      "Thomas H. Ptacek" <tqbf@enteract.com>
To:        marcs@znep.com
Cc:        tqbf@enteract.com, freebsd-security@FreeBSD.ORG
Subject:   Re: Privileged ports...
Message-ID:  <199703271941.NAA23050@enteract.com>
In-Reply-To: <Pine.BSF.3.95.970327063025.13195A-100000@alive.znep.com> from "Marc Slemko" at Mar 27, 97 06:38:58 am

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> I agree completely with you.  It is a very bad thing.  Start with the fact
> that, by default, inetd limits services to being called 256 times a minute
> and then shuts them off and then move on to more devious ways you could

inetd doesn't release the socket address when it shuts the port off, so I
doubt you'd be able to bind over something inetd's handling. You do have a
potential problem with specific binds (over inetd's INADDR_ANY) in this
configuration, though.

The real problem, as I see it, is that if reserved ports are enough of a
security concern for you that you'd dramatically complicate your inetd
configuration to handle them, you're going to have a real security concern
if inetd dies. I think it's bad to assume that an unprivileged user can't
cause a daemon to die.

> are set to a particular default but still allow them to be changed) that
> handles setting it then add a few lines of code to the kernel to allow you
> to set the uid who can bind to each priv'd port.  There are 1764 other
> things that it would be useful to be able to set in a similar way,

Why do you want a UID per reserved port? What is this getting you?

----------------
Thomas Ptacek at EnterAct, L.L.C., Chicago, IL [tqbf@enteract.com]
----------------
"If you're so special, why aren't you dead?"





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