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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
Date: Fri, 6 Sep 2002 10:04:06 +0000	[thread overview]
Message-ID: <20020906100406.C35@toy.ucw.cz> (raw)
In-Reply-To: <Pine.LNX.4.44.0209041311550.4000-100000@localhost.localdomain>; from mingo@elte.hu on Wed, Sep 04, 2002 at 01:13:28PM +0200

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.


  reply	other threads:[~2002-09-06 20:53 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-08-29 21:53 [PATCH] POSIX message queues pwaechtler
2002-08-30  9:48 ` Amos Waterland
2002-08-31 11:43   ` pwaechtler
2002-08-31 13:14     ` Krzysztof Benedyczak
2002-09-01  0:22     ` Amos Waterland
2002-09-01  1:50   ` Amos Waterland
2002-09-04 11:13     ` Ingo Molnar
2002-09-06 10:04       ` Pavel Machek [this message]
2002-09-07 14:16         ` pwaechtler
2002-09-06 22:48       ` Amos Waterland
2002-09-07 14:11         ` pwaechtler
2002-09-07 15:17           ` Ingo Molnar
2002-09-08 22:00             ` Amos Waterland
2002-08-31 12:53 ` Krzysztof Benedyczak
2002-09-07 14:39   ` pwaechtler
  -- strict thread matches above, loose matches on Subject: below --
2002-09-04 16:03 Manfred Spraul
2002-08-27 21:48 Krzysztof Benedyczak
2002-08-27 22:16 ` Christoph Hellwig
2002-08-31 13:28   ` Krzysztof Benedyczak
2002-09-01  7:24     ` Jakub Jelinek

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