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

[Andy Lutomirski]

On Tue, Nov 27, 2018 at 12:55 AM Dr. Greg <greg@xxxxxxxxxxxx> wrote:
> Since the thread has become a bit divergent I wanted to note that we
> have offered a proposal for a general policy management framework
> based on MRSIGNER values.  This framework is consistent with the SGX
> security model, ie. cryptographic rather then DAC based policy
> controls.  This framework also allows a much more flexible policy
> implementation that doesn't result in combinatoric issues.

Can you give a concrete explanation of a problem that your proposal
would solve?  As far as I can tell, it gets rid of a case in which an
unprivileged attacker who can run enclaves but hasn't compromised the
kernel can learn the PPID and other SGX-related permanent platform
identifiers, but it does nothing to prevent the same attacker from
learning non-SGX-related permanent identifiers, nor does it prevent
the attacker from using the Intel quoting enclave (unless configured
in a surprising way) and thus attesting to a remote system.

So what problem does it solve?