How does the client library get the attestation report from inside the VM? AMD

Danko Miladinovic 0 Reputation points
2023-04-20T09:53:21.2+00:00

Hi,

Are the VMs that are used on azure in confidential computing alterd in some way. I am asking this question because the client attestation library is getting the attestation report from inside the VM, the clien libray from this repository:
https://github.com/Azure/confidential-computing-cvm-guest-attestation I tried to run the cvm-attestation-sample-app on a AMD SEV secure VM and it did not work. The error was that the /dev/tpm was missing.

Best regards,
Danko

Azure Virtual Machines
Azure Virtual Machines
An Azure service that is used to provision Windows and Linux virtual machines.
7,283 questions
{count} votes

1 answer

Sort by: Most helpful
  1. kobulloc-MSFT 24,321 Reputation points Microsoft Employee
    2023-04-21T21:46:41.6966667+00:00

    Hello, @Danko Miladinovic !

    I'll summarize what we discussed in the comments for anyone else who may be interested.

    Why doesn't the sample application of the Azure confidential VM guest attestation work on my VM running outside of an Azure datacenter?

    The sample application of Azure confidential VM guest attestation only works for Azure confidential VMs running inside of an Azure Data center. This is largely due to two factors:

    1. Azure confidential VMs are using AMD SEV-SNP features
    2. Implementation differences: On-prem SEV VMs may have different firmware leveraging VMPL (Virtual Machine Privilege Levels) and virtual TPM (Trusted Platform Module) authenticated by Azure.

    More reading:

    0 comments No comments