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Date:   Mon, 29 Jun 2020 18:02:42 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc:     x86@kernel.org, linux-sgx@vger.kernel.org,
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Subject: Re: [PATCH v33 12/21] x86/sgx: Allow a limited use of
 ATTRIBUTE.PROVISIONKEY for attestation
Message-ID: <20200629160242.GB32176@zn.tnic>
References: <20200617220844.57423-1-jarkko.sakkinen@linux.intel.com>
 <20200617220844.57423-13-jarkko.sakkinen@linux.intel.com>
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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