SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support)

[Andy Lutomirski]

> On May 16, 2019, at 12:24 AM, James Morris <jmorris at namei.org> wrote:
>
>> On Wed, 15 May 2019, Andy Lutomirski wrote:
>>
>>> On Wed, May 15, 2019 at 3:46 PM James Morris <jmorris at namei.org> wrote:
>>>
>>> You could try user.sigstruct, which does not require any privs.
>>>
>>
>> I don't think I understand your proposal.  What file would this
>> attribute be on?  What would consume it?
>
> It would be on the enclave file, so you keep the sigstruct bound to it,
> rather than needing a separate file to manage.  It would simplify any LSM
> policy check.
>
> It would be consumed by (I guess) the SGX_INIT_THE_ENCLAVE ioctl in your
> example, instead of having a 2nd fd.
>
>

Okay, I think I see what you’re suggesting. I don’t think it works
well, though, since loading the data from the enclave file will almost
always be done in multiple chunks, and it’s not clear when the kernel
should look for the xattr or what to do if the xattr changes part way
through.