Re: [PATCH v17 18/23] platform/x86: Intel SGX driver

From: Jarkko Sakkinen
Date: Mon Nov 26 2018 - 17:16:52 EST

On Mon, Nov 26, 2018 at 05:00:39AM -0600, Dr. Greg wrote:
> We will be interested in your comments as to why the proposal is
> insufficient in the real world of FLC.
> I believe the proposed architecture can be defended as being effective
> in the real world, as it allows the root user to use cryptographic
> protections of access to the PROVISION bit and to enclave execution in
> general. On FLC that is the strongest guarantee that can be
> delivered.
> When we speak of 'unauthorized' users I believe we are speaking in the
> parlance of discretionary access controls which has a much wider TCB
> scope then the cryptographic model we are proposing. The model we
> propose allows the platform owner (root) to effectively implement the
> same level of security over the PROVISION bit that current locked
> platforms have, in a free and open fashion of course.
> We can certainly attempt to explain our position further.

I think kernel controlled provision would in all cases lower the
mitigations of thread scenarios (at least what you've presented so far)
assuming that a compromissed kernel could be detected fairly quickly,
wouldn't it?

Even without SGX, having a compromissed kernel, you can anyhow stealth
your malware in many ways.