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Roll-out and Provisioning

For secure roll-out and provisioning, several steps in a secure environment are required.

Set secure boot keys

Before deploying the base system, set the trust anchors of the software signing PKI, e.g., in UEFI variables. Set other required keys, e.g., the KEK and PK. See Secure Boot Configuration

Note: If you use release images from Github add the following public key to your efi db
ssig_subca.esl (sha256: b52d9451de399ac5ce8d443ff0e118295b2ad9f08d781e53bc8d662c83ac341)

Boot into provisioning mode

At the first boot, trust|me automatically boots into a provisioning mode. In this mode, the virtualization layer exposes additional functionality to the core container via the control interface. At that time, the deployed trust|me base system is equipped with the software signing trust anchor and is thus capable of starting the core container. In order to allow running other GuestOSes, you can add the GuestOS signing trust anchors to the certificate store in the virtualization layer (via the control interface). This allows the virtualization layer to verify any GuestOS that can be added to the system via the core container at any time.

Further, the virtualization layer initializes the TPM and creates a device CSR corresponding to a TPM-bound signing keypair. The core container can request the CSR from the virtualization layer. This allows to sign the device CSR using the Device Sub CA and to deploy the device certificate back to the target. During this step, the trust anchor for device certificates can be also be deployed in order to verify other device certificates, such as a backend, which may have a device identity in the same PKI hierarchy.

Lastly, the virtualization layer creates a softtoken for wrapping container encryption keys. This token can be replaced during provisioning with an own token, its password can be changed, or the token can be removed to use a Secure Element in future builds.

Complete provisioning

Reboot the system to complete the provisioning. During the next boot, the trust|me base system no longer boots into provisioning mode and can use the deployed certificates and tokens during operation. This means that the control interface available in the core container no longer exposes the provisioning functionality. Future builds will come up with functionality to replace relevant key material during the operation to complete the device lifecycle management.

Self-Provisioning

Current development builds contain a self-provisioning mechansim. The self provisioning first generates self-signed device certificates for testing. The pre-deployed software signing trust anchors is used on development builds to verify all containers, i.e. core containers and other deployed containers.

Further, an initial softtoken with password trustme is generated. The token is used to wrap the encryption keys for container data and emulates a Secure Element (or other tamper-resistant key store). In future builds, trust|me will allow storing these keys in Secure Elements. At every container start, the softtoken’s password must be provided via the core container to the virtualization layer, which unlocks the softtoken or Secure Element, respectively.

Complete self-provisioning

Just reboot the system after finishing initial provisioning with shell

reboot

Change the softtoken password

There are two options to change the passphrase of the softtoken.

1. Control Interface

You can just use the control tool to change the token’s passhprase at any time, either during provisioning or later on during normal operation by:

control change_pin

2. Openssl tool

You can change the password in the virtualization layer by running openssl during provisioning mode or at the debug shell in development builds.

# unwrap existing token
openssl pkcs12 -in /data/cml/tokens/testuser.p12 -out /tmp/mycert.pem -nodes
# rewrap existing token, set new password
openssl pkcs12 -export -out /data/cml/tokens/testuser.p12 -in tmp/mycert.pem
# remove temp file
rm /tmp/mycert.pem