arbiter/server/crates/arbiter-server/tests/user_agent/unseal.rs

use arbiter_proto::proto::user_agent::{
    AuthChallengeRequest, UnsealEncryptedKey, UnsealResult, UnsealStart,
    UserAgentRequest,
    user_agent_request::Payload as UserAgentRequestPayload,
    user_agent_response::Payload as UserAgentResponsePayload,
};
use arbiter_server::{
    actors::{
        GlobalActors,
        bootstrap::GetToken,
        keyholder::{Bootstrap, Seal},
        user_agent::{UserAgentActor, UserAgentError},
    },
    db,
};
use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
use memsafe::MemSafe;
use x25519_dalek::{EphemeralSecret, PublicKey};


async fn setup_authenticated_user_agent(
    seal_key: &[u8],
) -> (
    arbiter_server::db::DatabasePool,
    UserAgentActor,
) {
    let db = db::create_test_pool().await;

    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
    actors
        .key_holder
        .ask(Bootstrap {
            seal_key_raw: MemSafe::new(seal_key.to_vec()).unwrap(),
        })
        .await
        .unwrap();
    actors.key_holder.ask(Seal).await.unwrap();

    let mut user_agent = UserAgentActor::new_manual(db.clone(), actors.clone());

    let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
    let auth_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
    user_agent
        .process_transport_inbound(UserAgentRequest {
            payload: Some(UserAgentRequestPayload::AuthChallengeRequest(
                AuthChallengeRequest {
                    pubkey: auth_key.verifying_key().to_bytes().to_vec(),
                    bootstrap_token: Some(token),
                },
            )),
        })
        .await
        .unwrap();

    (db, user_agent)
}

async fn client_dh_encrypt(
    user_agent: &mut UserAgentActor,
    key_to_send: &[u8],
) -> UnsealEncryptedKey {
    let client_secret = EphemeralSecret::random();
    let client_public = PublicKey::from(&client_secret);

    let response = user_agent
        .process_transport_inbound(UserAgentRequest {
            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
                client_pubkey: client_public.as_bytes().to_vec(),
            })),
        })
        .await
        .unwrap();

    let server_pubkey = match response.payload.unwrap() {
        UserAgentResponsePayload::UnsealStartResponse(resp) => resp.server_pubkey,
        other => panic!("Expected UnsealStartResponse, got {other:?}"),
    };
    let server_public = PublicKey::from(<[u8; 32]>::try_from(server_pubkey.as_slice()).unwrap());

    let shared_secret = client_secret.diffie_hellman(&server_public);
    let cipher = XChaCha20Poly1305::new(shared_secret.as_bytes().into());
    let nonce = XNonce::from([0u8; 24]);
    let associated_data = b"unseal";
    let mut ciphertext = key_to_send.to_vec();
    cipher
        .encrypt_in_place(&nonce, associated_data, &mut ciphertext)
        .unwrap();

    UnsealEncryptedKey {
        nonce: nonce.to_vec(),
        ciphertext,
        associated_data: associated_data.to_vec(),
    }
}

fn unseal_key_request(req: UnsealEncryptedKey) -> UserAgentRequest {
    UserAgentRequest {
        payload: Some(UserAgentRequestPayload::UnsealEncryptedKey(req)),
    }
}

#[tokio::test]
#[test_log::test]
pub async fn test_unseal_success() {
    let seal_key = b"test-seal-key";
    let (_db, mut user_agent) = setup_authenticated_user_agent(seal_key).await;

    let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;

    let response = user_agent
        .process_transport_inbound(unseal_key_request(encrypted_key))
        .await
        .unwrap();

    assert_eq!(
        response.payload.unwrap(),
        UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
    );
}

#[tokio::test]
#[test_log::test]
pub async fn test_unseal_wrong_seal_key() {
    let (_db, mut user_agent) = setup_authenticated_user_agent(b"correct-key").await;

    let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;

    let response = user_agent
        .process_transport_inbound(unseal_key_request(encrypted_key))
        .await
        .unwrap();

    assert_eq!(
        response.payload.unwrap(),
        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
    );
}

#[tokio::test]
#[test_log::test]
pub async fn test_unseal_corrupted_ciphertext() {
    let (_db, mut user_agent) = setup_authenticated_user_agent(b"test-key").await;

    let client_secret = EphemeralSecret::random();
    let client_public = PublicKey::from(&client_secret);

    user_agent
        .process_transport_inbound(UserAgentRequest {
            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
                client_pubkey: client_public.as_bytes().to_vec(),
            })),
        })
        .await
        .unwrap();

    let response = user_agent
        .process_transport_inbound(unseal_key_request(UnsealEncryptedKey {
            nonce: vec![0u8; 24],
            ciphertext: vec![0u8; 32],
            associated_data: vec![],
        }))
        .await
        .unwrap();

    assert_eq!(
        response.payload.unwrap(),
        UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
    );
}

#[tokio::test]
#[test_log::test]
pub async fn test_unseal_start_without_auth_fails() {
    let db = db::create_test_pool().await;

    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
    let mut user_agent = UserAgentActor::new_manual(db.clone(), actors);

    let client_secret = EphemeralSecret::random();
    let client_public = PublicKey::from(&client_secret);

    let result = user_agent
        .process_transport_inbound(UserAgentRequest {
            payload: Some(UserAgentRequestPayload::UnsealStart(UnsealStart {
                client_pubkey: client_public.as_bytes().to_vec(),
            })),
        })
        .await;

    match result {
        Err(err) => {
            assert_eq!(err, UserAgentError::StateTransitionFailed);
        }
        other => panic!("Expected state machine error, got {other:?}"),
    }
}

#[tokio::test]
#[test_log::test]
pub async fn test_unseal_retry_after_invalid_key() {
    let seal_key = b"real-seal-key";
    let (_db, mut user_agent) = setup_authenticated_user_agent(seal_key).await;

    {
        let encrypted_key = client_dh_encrypt(&mut user_agent, b"wrong-key").await;

        let response = user_agent
            .process_transport_inbound(unseal_key_request(encrypted_key))
            .await
            .unwrap();

        assert_eq!(
            response.payload.unwrap(),
            UserAgentResponsePayload::UnsealResult(UnsealResult::InvalidKey.into()),
        );
    }

    {
        let encrypted_key = client_dh_encrypt(&mut user_agent, seal_key).await;

        let response = user_agent
            .process_transport_inbound(unseal_key_request(encrypted_key))
            .await
            .unwrap();

        assert_eq!(
            response.payload.unwrap(),
            UserAgentResponsePayload::UnsealResult(UnsealResult::Success.into()),
        );
    }
}