Reference Value Provider Service, or RVPS for short, is a component to receive software supply chain provenances/metadata, verify them, and extract the reference values. All the reference values will be stored inside RVPS. When the Attestation Service queries specific software claims, RVPS will response with related reference values.

RVPS contains the following components:

• Pre-Processor : Pre-Processor contains a set of Wares (like Middleware). The Wares can process the input Message and then deliver it to the Extractors.

• Extractors : Extractors has sub-modules to process different types of provenance. Each sub-module will consume the input Message, and then generate an output Reference Value.

• Store : Store is a trait object, which can provide a key-value like API. All verified reference values will be stored in the Store. When requested by Attestation Service, related reference value will be provided.

The following figure illustrates the message flow of RVPS:

A protocol helps to distribute provenance of binaries. It will be received and processed by RVPS, then RVPS will generate a Reference Value if working correctly.

{
    "version": <VERSION-NUMBER-STRING>,
    "type": <TYPE-OF-THE-PROVENANCE-STRING>,
    "provenance": #provenance,
}

The "version" field is the version of this message, making extensibility possible.

The "type" field specifies the concrete type of the provenance the message carries.

The "provenance" field is the main content passed to RVPS. This field contains the payload to be decrypted by RVPS. The meaning of the provenance depends on the type and concrete Extractor which process this.

It is the reference values really requested and used by Attestation Service to compare with the gathered evidence generated from HW TEE. They are usually digests. To avoid ambiguity, they are named trust digests rather than reference values.

Install the protocol buffer compiler package protobuf-compiler.

In this way, the RVPS can run as a single service. The gRPC protos are defined.

We can run using the following command

git clone https://github.com/confidential-containers/trustee
cd trustee/rvps
make build && sudo make install

Run RVPS

rvps

By default RVPS listens on localhost:50003 waiting for requests.

We can build an RVPS docker image

cd .. && docker build -t rvps -f rvps/docker/Dockerfile .

Run the container

docker run -d -p 50003:50003 rvps --address 0.0.0.0:50003

Or we can build RVPS as a podman image

cd .. && podman build -t rvps -f rvps/podman/Containerfile .

Run

podman run -d -p 50003:50003 --net host rvps

RVPS can be launched with a specified configuration file by -c flag. A configuration file looks like

{
    "storage": {
        "type": "LocalFs",
        "file_path": "/opt/confidential-containers/attestation-service/reference_values"
    }
}

• storage.type: backend storage type to store reference values. Currently LocalFs and LocalJson are supported.
• storage.*: Each different type of storage has its own associated configuration parameters. This is also a JSON map object.

In this mode, the RVPS will work as a crate inside the Attestation Service binary.

In this mode, the Attestation Service will connect to a remote RVPS. This requires the Attestation Service to be built with feature rvps-grpc.

cd ../attestation-service && cargo run --bin as-grpc -- --config-file config.json

The rvps-tool tool is a command line client to interact with RVPS. It can:

• Register reference values into the RVPS
• Query reference values from the RVPS
• Delete reference values from the RVPS

Run RVPS in docker or by issuing the following commands

RVPS_ADDR=127.0.0.1:50003
rvps --address $RVPS_ADDR

Create a test message in sample format

cat << EOF > sample
{
    "test-binary-1": [
        "reference-value-1",
        "reference-value-2"
    ],
    "test-binary-2": [
        "reference-value-3",
        "reference-value-4"
    ]
}
EOF
provenance=$(cat sample | base64 --wrap=0)
cat << EOF > message
{
    "version" : "0.1.0",
    "type": "sample",
    "payload": "$provenance"
}
EOF

Register the provenance into RVPS

rvps-tool register --path ./message --addr http://$RVPS_ADDR

It will say something like

[2023-03-09T04:44:11Z INFO  rvps_client] Register provenance succeeded.

Let's then query the reference values

rvps-tool query --addr http://$RVPS_ADDR

The output should display something like the following:

[2025-01-24T06:04:41Z INFO  rvps_tool] Get reference values succeeded:
     {"test-binary-1":["reference-value-1","reference-value-2"],
      "test-binary-2":["reference-value-3","reference-value-4"]}

Finally, let's delete a reference value

rvps-tool delete --name test-binary-1 --addr http://$RVPS_ADDR

It will say something like

[2025-01-24T06:05:15Z INFO  rvps_tool] Delete reference value succeeded.

Query again to verify the deletion:

rvps-tool query --addr http://$RVPS_ADDR

The output should now show that "test-binary-1" has been removed:

[2025-01-24T06:05:30Z INFO  rvps_tool] Get reference values succeeded:
     {"test-binary-2":["reference-value-3","reference-value-4"]}