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Date: Tue, 30 Oct 2007 12:30:18 -0000
Subject: Re: Defense in depth: LSM *modules*, not a static interface
From: "Simon Arlott" <simon@fire.lp0.eu>
To: "Cliffe" <cliffe@ii.net>
Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
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On Tue, October 30, 2007 07:14, Cliffe wrote:
> And while I acknowledge that many of these layers are currently buried
> within the kernel (netfilter...) they are security layers which in many
> cases would probably make sense as stackable security modules.
>
> Making the interface static forces mammoth solutions which then must
> attempt to solve all of the above in one ls*m*. What happened to
> dividing tasks into easy to manage chunks?

Would it be possible to have Kconfig select which LSM should handle each
area of security? Selecting LSM A would automatically disable LSM B and
C since they both implement the same security functions, while LSM D
would still be selectable since it implements something else. The default
capabilities code would then turn off parts of itself that another LSM
is handling.

Alternatively the M in LSM can be restored and modules can be stacked.
It should be possible for the primary LSM to check the security_ops of the
secondary LSM(s) and complain if it considers there to be an incompatiblity.

-- 
Simon Arlott
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