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edgelesssys / constellation

Constellation is the first Confidential Kubernetes. Constellation shields entire Kubernetes clusters from the (cloud) infrastructure using confidential computing.
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spiffe/spire to proof: running on aws and in memory encrypted context #2667

Open hpvd opened 11 months ago

hpvd commented 11 months ago

Use case

Originally it is about things running within kubernetes, but I think it's worth to share - maybe this idea can somehow be adapted for hardening constellation:

We can now assert two statements are true, our agent runs:

  • On an AWS EC2 machine
  • In a memory encrypted context

https://control-plane.io/posts/spiffe-confidential-computing-august-2023/

spiffe intros: https://spiffe.io/ https://github.com/spiffe/spire https://control-plane.io/posts/spiffe-keystone-of-cloud-native/

and the spiffe plugin: RFC: SEV SNP Node Attestation Plugin https://github.com/spiffe/spire/issues/4469

Describe your solution

No response

Would you be willing to implement this feature?

3u13r commented 11 months ago

Hello,

the following points are already verified by Constellation:

We can now assert two statements are true, our agent runs:

On an AWS EC2 machine
In a memory encrypted context

This is because AWS is enrolled with AMD to use a VLEK instead of a VCEK (https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56860.pdf Section 3.6 and https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/snp-attestation.html). If you create a Constellation on AWS this is verified during constellation apply. To have a look at the VLEK certificate you can execute constellation verify. Sadly, AMD's specification is a bit behind their implementation. If you take the raw X.509 and have a look at the extension with OID 1.3.6.1.4.1.3704.1.5 it states CN=cc-eu-west-1.amazonaws.com.

Therefore, you already can prove that the VM is located in a specific AWS region. You cannot bind the name of the EC2 instance to the attestation but you have a better TCB since you don't have to reply on AWS' IMDS API. Does this already has the security properties you need? It would be great to have a clear picture of your requirements.

Also, with Constellation being a Kubernetes distribution pinning against concrete VM names sounds counter intuitive at first since e.g. on a Constellation upgrade all the nodes are replaced.

hpvd commented 9 months ago

just an example on this topic in general: why and how uber uses spiffe/spire: https://www.uber.com/en-DE/blog/our-journey-adopting-spiffe-spire/