Re: [PATCH v39 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION

[Dave Hansen]

On 10/23/20 3:17 AM, Jarkko Sakkinen wrote:
> On Tue, Oct 20, 2020 at 02:19:26PM -0700, Dave Hansen wrote:
>> On 10/2/20 9:50 PM, Jarkko Sakkinen wrote:
>>> + * Failure to explicitly request access to a restricted attribute will cause
>>> + * sgx_ioc_enclave_init() to fail.  Currently, the only restricted attribute
>>> + * is access to the PROVISION_KEY.
>> Could we also justify why access is restricted, please?  Maybe:
>>
>> 	Access is restricted because PROVISION_KEY is burned uniquely
>> 	into each each processor, making it a perfect unique identifier
>> 	with privacy and fingerprinting implications.
>>
>> Are there any other reasons for doing it this way?
> AFAIK, if I interperet the SDM correctl, PROVISION_KEY and
> PROVISION_SEALING_KEY also have random salt added, i.e. they change
> every boot cycle.
> 
> There is "RAND = yes" on those keys in Table 40-64 of Intel SDM volume
> 3D :-)

Does that mean there are no privacy implications from access to the
provisioning keys?  If that's true, why do we need a separate permission
framework for creating provisioning enclaves?