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Date: Fri, 6 Sep 2002 10:04:06 +0000
From: Pavel Machek <pavel@suse.cz>
To: Ingo Molnar <mingo@elte.hu>
Cc: Amos Waterland <apw@us.ibm.com>, pwaechtler@mac.com,
       golbi@mat.uni.torun.pl, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] POSIX message queues
Message-ID: <20020906100406.C35@toy.ucw.cz>
References: <20020901015025.A10102@kvasir.austin.ibm.com> <Pine.LNX.4.44.0209041311550.4000-100000@localhost.localdomain>
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Hi!

> > That is the fundamental problem with a userspace shared memory
> > implementation: write permissions on a message queue should grant
> > mq_send(), but write permissions on shared memory grant a lot more than
> > just that.
> 
> is it really a problem? As long as the read and write queues are separated
> per sender, all that can happen is that a sender is allowed to read his
> own messages - that is not an exciting capability.

Imagine something that writes data into the que then erases the data and
gets rid of setuid.
								Pavel
-- 
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.

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