Subject: Re: [PATCH 3/3] security: allow capable check to permit mmap or
	low vm space
From: Eric Paris <eparis@redhat.com>
To: James Morris <jmorris@namei.org>
Cc: linux-kernel@vger.kernel.org, sds@tycho.nsa.gov, selinux@tycho.nsa.gov,
       alan@redhat.com, chrisw@redhat.com, hpa@zytor.com,
       akpm@linux-foundation.org
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	 <Xine.LNX.4.64.0711170845050.22208@us.intercode.com.au>
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Date: Fri, 16 Nov 2007 16:53:29 -0500
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On Sat, 2007-11-17 at 08:47 +1100, James Morris wrote:
> On Fri, 16 Nov 2007, Eric Paris wrote:
> 
> > On a kernel with CONFIG_SECURITY but without an LSM which implements
> > security_file_mmap it is impossible for an application to mmap addresses
> > lower than mmap_min_addr.
> 
> Actually, should we be doing any checking in the dummy module, given that 
> it is not done with !CONFIG_SECURITY ?

I'm not sure I understand the question.  We already do a number of
capable type security checks in dummy functions. See dummy_settime() as
just one example.

If we have !CONFIG_SECURITY we don't have any security protections (how
could we?  we turned them off) so we don't get into dummy hooks.  If we
do checks or not in uncompiled code doesn't seem to me to matter.

Maybe I'm just confused...

-Eric

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