Attestation Agent

Attestation Agent (AA for short) is a service function set for attestation procedure in Confidential Containers. It provides kinds of service APIs that need to make requests to the Relying Party (Key Broker Service) in Confidential Containers, and performs an attestation and establishes connection between the Key Broker Client (KBC) and corresponding KBS, so as to obtain the trusted services or resources of KBS.

Current consumers of AA include:

• ocicrypt-rs
• image-rs

Components

The main body of AA is a rust library crate, which contains KBC modules used to communicate with various KBS. In addition, this project also provides a gRPC service application, which allows callers to call the services provided by AA through gRPC.

Library crate

Import AA in Cargo.toml of your project with specific KBC(s):

attestation-agent = { git = "https://github.com/confidential-containers/guest-components", features = ["sample_kbc"] }

Note: When the version is stable, we will release AA on https://crate.io.

gRPC Application

Here are the steps of building and running gRPC application of AA:

Build

Build and install with default KBC modules:

git clone https://github.com/confidential-containers/guest-components
cd guest-components/attestation-agent
make && make install

or explicitly specify the KBS modules it contains. Taking sample_kbc as example:

make KBC=sample_kbc

Musl

To build and install with musl, just run:

make LIBC=musl && make install

Openssl support

To build and install with openssl support (which is helpful in specific machines like s390x)

make OPENSSL=1 && make install

Run

For help information, just run:

attestation-agent --help

Start AA and specify the endpoint of AA’s gRPC service:

attestation-agent --keyprovider_sock 127.0.0.1:50000 --getresource_sock 127.0.0.1:50001

Or start AA with default keyprovider address (127.0.0.1:50000) and default getresource address (127.0.0.1:50001):

attestation-agent

If you want to see the runtime log:

RUST_LOG=attestation_agent attestation-agent --keyprovider_sock 127.0.0.1:50000 --getresource_sock 127.0.0.1:50001

ttRPC

To build and install ttRPC Attestation Agent, just run:

make ttrpc=true && make install

ttRPC AA now only support Unix Socket, for example:

attestation-agent --keyprovider_sock unix:///tmp/keyprovider.sock --getresource_sock unix:///tmp/getresource.sock

Supported KBC modules

AA provides a flexible KBC module mechanism to support different KBS protocols required to make the communication between KBC and KBS. If the KBC modules currently supported by AA cannot meet your use requirement (e.g, need to use a new KBS protocol), you can write a new KBC module complying with the KBC development GUIDE. Welcome to contribute new KBC module to this project!

List of supported KBC modules:

CC KBC

CC KBC supports different kinds of hardware TEE attesters, now

To build cc kbc with all available attesters and install, use

make KBC=cc_kbc && make install

Tools

• Sample Keyprovider: A simple tool for encrypting container images with skopeo, please refer to its README.