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Date: Tue, 10 Apr 2012 16:32:10 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Oleg Nesterov <oleg@redhat.com>
CC: Cyrill Gorcunov <gorcunov@openvz.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
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        Glauber Costa <glommer@parallels.com>,
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        Jonathan Corbet <corbet@lwn.net>
Subject: Re: + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree
References: <20120215143606.GA14037@redhat.com> <20120215160652.GA17680@redhat.com> <20120215162752.GF4533@moon> <20120409151027.7f3e0fa5.akpm@linux-foundation.org> <20120409222443.GW1625@moon> <4F836F3E.9090207@zytor.com> <20120410223758.GL24857@moon> <20120410230833.GA17620@redhat.com>
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On 04/10/2012 04:08 PM, Oleg Nesterov wrote:
> 
> OK, since this is discussed again...
> 
> Can this comment can also explain why do we obfuscate the pointers
> by type? I mean, I don't really understand why the one-dimensional
> cookies[2] is "not enough" from security pov.
> 

Because it's cheap.  "Just enough" is not what you want to shoot for,
ever, you want to get past the "just enough" point and then consider
"what can I get for cheap at this point"?

	-hpa