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From: Bill Paul <wpaul@skynet.ctr.columbia.edu>
Message-Id: <199611251403.JAA05764@skynet.ctr.columbia.edu>
Subject: Re: looking for an idea
To: j@uriah.heep.sax.de (J Wunsch)
Date: Mon, 25 Nov 1996 09:03:53 -0500 (EST)
Cc: hackers@freebsd.org
In-Reply-To: <199611250935.KAA16590@uriah.heep.sax.de> from "J Wunsch" at Nov 25, 96 10:35:28 am
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Of all the gin joints in all the towns in all the world, J Wunsch had to 
walk into mine and say:

> As Bill Paul wrote:
> 
> > Now, the problem is to find a way for A to verify B's UID without
> > resorting to grovelling in /dev/kmem. This is necessary since A would
> > need privileges to open /dev/kmem, and A and B might not be run by
> > privileged users.
> 
> /proc/$pid/status is readable by everyone, and contains the real and
> effective UID of the process.

I'm sorry that's incorrect, but that's for playing.

You didn't read the rest of my message, did you.

I said that I'd already thought of using /proc; I also said that in
order for that to work, I would need to know B's PID first (or am I 
supposed to just pull $pid out of thin air). Learning the PID of B is 
just as big a problem as learning the UID of B. Also, it doesn't work
if, for some reason, PROCFS isn't configured in the kernel or /proc
isn't mounted.

-Bill

-- 
=============================================================================
-Bill Paul            (212) 854-6020 | System Manager, Master of Unix-Fu
Work:         wpaul@ctr.columbia.edu | Center for Telecommunications Research
Home:  wpaul@skynet.ctr.columbia.edu | Columbia University, New York City
=============================================================================
 "If you're ever in trouble, go to the CTR. Ask for Bill. He will help you."
=============================================================================