Re: [PATCH v4 17/18] nitro_enclaves: Add overview documentation

[Stefan Hajnoczi]

On Wed, Jun 24, 2020 at 05:39:39PM +0300, Paraschiv, Andra-Irina wrote:
> 
> 
> On 23/06/2020 11:59, Stefan Hajnoczi wrote:
> > On Mon, Jun 22, 2020 at 11:03:28PM +0300, Andra Paraschiv wrote:
> > > +The kernel bzImage, the kernel command line, the ramdisk(s) are part of the
> > > +Enclave Image Format (EIF); plus an EIF header including metadata such as magic
> > > +number, eif version, image size and CRC.
> > > +
> > > +Hash values are computed for the entire enclave image (EIF), the kernel and
> > > +ramdisk(s). That's used, for example, to check that the enclave image that is
> > > +loaded in the enclave VM is the one that was intended to be run.
> > > +
> > > +These crypto measurements are included in a signed attestation document
> > > +generated by the Nitro Hypervisor and further used to prove the identity of the
> > > +enclave; KMS is an example of service that NE is integrated with and that checks
> > > +the attestation doc.
> > > +
> > > +The enclave image (EIF) is loaded in the enclave memory at offset 8 MiB. The
> > > +init process in the enclave connects to the vsock CID of the primary VM and a
> > > +predefined port - 9000 - to send a heartbeat value - 0xb7. This mechanism is
> > > +used to check in the primary VM that the enclave has booted.
> > > +
> > > +If the enclave VM crashes or gracefully exits, an interrupt event is received by
> > > +the NE driver. This event is sent further to the user space enclave process
> > > +running in the primary VM via a poll notification mechanism. Then the user space
> > > +enclave process can exit.
> > > +
> > > +[1] https://aws.amazon.com/ec2/nitro/nitro-enclaves/
> > > +[2] https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt
> > > +[3] https://lwn.net/Articles/807108/
> > > +[4] https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
> > > +[5] https://man7.org/linux/man-pages/man7/vsock.7.html
> > Is the EIF specification and the attestation protocol available?
> 
> For now, they are not publicly available. Once the refs are available (e.g.
> AWS documentation, GitHub documentation), I'll include them in the kernel
> documentation as well.
> 
> As a note here, the NE project is currently in preview
> (https://aws.amazon.com/ec2/nitro/nitro-enclaves/) and part of the
> documentation / codebase will be publicly available when NE is generally
> available (GA). This will be in addition to the ones already publicly
> available, like the NE kernel driver.
> 
> Let me know if I can help with any particular questions / clarifications.

Thanks!

Stefan

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