On Thu, Jun 18, 2020 at 01:08:34AM +0300, Jarkko Sakkinen wrote:

Provisioning Certification Enclave (PCE), the root of trust for other
enclaves, generates a signing key from a fused key called Provisioning
Certification Key. PCE can then use this key to certify an attestation key
of a QE, e.g. we get the chain of trust down to the hardware if the Intel

What's a QE?

I don't see this acronym resolved anywhere in the whole patchset.

signed PCE is used.

To use the needed keys, ATTRIBUTE.PROVISIONKEY is required but should be
only allowed for those who actually need it so that only the trusted
parties can certify QE's.

Obviously the attestation service should know the public key of the used
PCE and that way detect illegit attestation, but whitelisting the legit
users still adds an additional layer of defence.

Add new device file called /dev/sgx/provision. The sole purpose of this
file is to provide file descriptors that act as privilege tokens to allow
to build enclaves with ATTRIBUTE.PROVISIONKEY set. A new ioctl called
SGX_IOC_ENCLAVE_SET_ATTRIBUTE is used to assign this token to an enclave.

So I'm sure I'm missing something here: what controls which
enclave can open /dev/sgx/provision and thus pass the FD to
SGX_IOC_ENCLAVE_SET_ATTRIBUTE?

And in general, how does that whole flow look like: what calls
SGX_IOC_ENCLAVE_SET_ATTRIBUTE when?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette