Re: [PATCH 05/25] x86/sgx: Introduce runtime protection bits

[Jarkko Sakkinen]

On Fri, Jan 14, 2022 at 04:01:33PM -0800, Reinette Chatre wrote:
> Hi Jarkko,
> 
> On 1/14/2022 3:15 PM, Jarkko Sakkinen wrote:
> > On Fri, Jan 14, 2022 at 03:05:21PM -0800, Reinette Chatre wrote:
> >> Hi Jarkko,
> > 
> > How enclave can check a page range that EPCM has the expected permissions?
> 
> Only way to change EPCM permissions from outside enclave is to run ENCLS[EMODPR]
> that needs to be accepted from within the enclave via ENCLU[EACCEPT]. At that
> time the enclave provides the expected permissions and that will fail
> if there is a mismatch with the EPCM permissions (SGX_PAGE_ATTRIBUTES_MISMATCH).

This is a very valid point but that does make the introspection possible
only at the time of EACCEPT.

It does not give tools for enclave to make sure that EMODPR-ETRACK dance
was ever exercised.

/Jarkko