thegraph-core 0.15.2

//! Attestation types and functions for verifying attestations.

use alloy::{
    primitives::{Address, B256, ChainId, Signature, b256, keccak256, normalize_v},
    signers::SignerSync,
    sol_types::{Eip712Domain, SolStruct, eip712_domain},
};

use crate::{allocation_id::AllocationId, deployment_id::DeploymentId};

/// Attestation EIP-712 domain salt
const ATTESTATION_EIP712_DOMAIN_SALT: B256 =
    b256!("a070ffb1cd7409649bf77822cce74495468e06dbfaef09556838bf188679b9c2");

/// An attestation of a request-response pair.
///
/// An attestation is an EIP-712 signature over a request, `request_cid`, and response,
/// `response_cid`, keccak-256 hash, and the subgraph deployment ID, `deployment`, being queried.
///
/// The attestation is signed by the indexer that processed the request. The indexer signs the
/// allocation by signing the EIP-712 hash with the private key of the allocation associated with
/// the deployment being queried.
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct Attestation {
    /// The keccak-256 hash of the request being attested.
    #[cfg_attr(feature = "serde", serde(rename = "requestCID"))]
    pub request_cid: B256,
    /// The keccak-256 hash of the response being attested.
    #[cfg_attr(feature = "serde", serde(rename = "responseCID"))]
    pub response_cid: B256,
    /// The subgraph deployment ID being queried.
    #[cfg_attr(feature = "serde", serde(rename = "subgraphDeploymentID"))]
    pub deployment: B256,
    /// The `r` component of the attestation signature.
    pub r: B256,
    /// The `s` component of the attestation signature.
    pub s: B256,
    /// The parity indicator of the attestation signature.
    pub v: u8,
}

alloy::sol! {
    /// EIP-712 receipt struct for attestation signing.
    struct Receipt {
        bytes32 requestCID;
        bytes32 responseCID;
        bytes32 subgraphDeploymentID;
    }
}

/// Errors that can occur when verifying an attestation.
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, thiserror::Error)]
pub enum VerificationError {
    /// The request hash in the attestation does not match the expected request hash
    #[error("invalid request hash")]
    InvalidRequestHash,

    /// The response hash in the attestation does not match the expected response hash
    #[error("invalid response hash")]
    InvalidResponseHash,

    /// Failed to recover the signer addres (allocation address) from the attestation signature
    #[error("failed to recover signer")]
    FailedSignerRecovery,

    /// The recovered signer address does not match the expected signer address
    #[error("recovered signer is not expected")]
    RecoveredSignerNotExpected,
}

/// Create an EIP-712 domain given a chain ID and dispute manager address.
pub fn eip712_domain(chain_id: ChainId, dispute_manager: Address) -> Eip712Domain {
    eip712_domain! {
        name: "Graph Protocol",
        version: "0",
        chain_id: chain_id,
        verifying_contract: dispute_manager,
        salt: ATTESTATION_EIP712_DOMAIN_SALT,
    }
}

/// Verify an attestation.
///
/// Checks that the request and response hashes match the attestation, and the address recovered
/// from the signature of the attestation matches the expected signer.
pub fn verify(
    domain: &Eip712Domain,
    attestation: &Attestation,
    expected_signer: &Address,
    request: &str,
    response: &str,
) -> Result<(), VerificationError> {
    // Check that the request and response hashes match the attestation
    if attestation.request_cid != keccak256(request) {
        return Err(VerificationError::InvalidRequestHash);
    }

    // Check that the request and response hashes match the attestation
    if attestation.response_cid != keccak256(response) {
        return Err(VerificationError::InvalidResponseHash);
    }

    // Recover the attestation signer public address (the allocation address) from the attestation
    // and check that it matches the expected signer address
    let signer = recover_allocation(domain, attestation)?;
    if &signer != expected_signer {
        return Err(VerificationError::RecoveredSignerNotExpected);
    }

    Ok(())
}

/// Create an attestation.
///
/// Signs the attestation with the signer's private key.
pub fn create<S: SignerSync>(
    domain: &Eip712Domain,
    signer: &S,
    deployment: &DeploymentId,
    request: &str,
    response: &str,
) -> Attestation {
    let msg = Receipt {
        requestCID: keccak256(request),
        responseCID: keccak256(response),
        subgraphDeploymentID: deployment.into(),
    };

    let signature = signer
        .sign_typed_data_sync(&msg, domain)
        .expect("failed to sign attestation");

    Attestation {
        request_cid: msg.requestCID,
        response_cid: msg.responseCID,
        deployment: deployment.into(),
        r: signature.r().into(),
        s: signature.s().into(),
        v: signature.recid().into(),
    }
}

/// Recover the signer's allocation address from the attestation.
pub fn recover_allocation(
    domain: &Eip712Domain,
    attestation: &Attestation,
) -> Result<AllocationId, VerificationError> {
    // Recover the signature components
    let signature_parity =
        normalize_v(attestation.v as u64).ok_or(VerificationError::FailedSignerRecovery)?;
    let signature_r = attestation.r.into();
    let signature_s = attestation.s.into();

    // Calculate the signing hash
    let msg = Receipt {
        requestCID: attestation.request_cid,
        responseCID: attestation.response_cid,
        subgraphDeploymentID: attestation.deployment,
    };
    let signing_hash = msg.eip712_signing_hash(domain);

    // Recover the allocation ID from the signature
    Signature::new(signature_r, signature_s, signature_parity)
        .recover_address_from_prehash(&signing_hash)
        .map(Into::into)
        .map_err(|_| VerificationError::FailedSignerRecovery)
}

#[cfg(feature = "fake")]
impl fake::Dummy<fake::Faker> for Attestation {
    fn dummy_with_rng<R: fake::Rng + ?Sized>(config: &fake::Faker, rng: &mut R) -> Self {
        Self {
            request_cid: B256::from(<[u8; 32]>::dummy_with_rng(config, rng)),
            response_cid: B256::from(<[u8; 32]>::dummy_with_rng(config, rng)),
            deployment: DeploymentId::dummy_with_rng(config, rng).into(),
            r: B256::from(<[u8; 32]>::dummy_with_rng(config, rng)),
            s: B256::from(<[u8; 32]>::dummy_with_rng(config, rng)),
            v: u8::dummy_with_rng(config, rng),
        }
    }
}

#[cfg(test)]
mod tests {
    use alloy::{
        primitives::{Address, B256, ChainId, address, b256},
        signers::{SignerSync, local::PrivateKeySigner},
        sol_types::Eip712Domain,
    };

    use super::{Attestation, create, eip712_domain, verify};
    use crate::{DeploymentId, deployment_id};

    const CHAIN_ID: ChainId = 1337;
    const DISPUTE_MANAGER_ADDRESS: Address = address!("16def7e0108a5467a106DBd7537F8591F470342e");
    const ALLOCATION_ADDRESS: Address = address!("90f8bf6a479f320ead074411a4b0e7944ea8c9c1");
    const ALLOCATION_PRIVATE_KEY: B256 =
        b256!("4f3edf983ac636a65a842ce7c78d9aa706d3b113bce9c46f30d7d21715b23b1d");
    const DEPLOYMENT: DeploymentId =
        deployment_id!("QmeVg9Da6uyBvjUEy5JqCgw2VKdkTxjPvcYuE5riGpkqw1");

    /// Create a domain for testing:
    /// - `chain_id`: `1337`
    /// - `dispute_manager`: `0x16DEF7E0108A5467A106dbD7537f8591f470342E`
    fn domain() -> Eip712Domain {
        eip712_domain(CHAIN_ID, DISPUTE_MANAGER_ADDRESS)
    }

    /// Create a signer for testing
    ///
    /// - `private_key`: `0x4f3edf983ac636a65a842ce7c78d9aa706d3b113bce9c46f30d7d21715b23b1d`
    /// - `address`: `0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1`
    ///
    /// Returns the allocation address and signer.
    fn signer() -> (Address, impl SignerSync) {
        (
            ALLOCATION_ADDRESS,
            PrivateKeySigner::from_bytes(&ALLOCATION_PRIVATE_KEY).expect("failed to create signer"),
        )
    }

    /// Verify an attestation (created by old indexer-native module from TS indexer implementation)
    #[test]
    fn verify_attestation() {
        //* Given
        let domain = domain();
        let (address, _signer) = signer();
        let deployment = DEPLOYMENT;

        let request = "foo";
        let response = "bar";

        let attestation = Attestation {
            request_cid: b256!("41b1a0649752af1b28b3dc29a1556eee781e4a4c3a1f7f53f90fa834de098c4d"),
            response_cid: b256!("435cd288e3694b535549c3af56ad805c149f92961bf84a1c647f7d86fc2431b4"),
            deployment: deployment.into(),
            r: b256!("e1fb47e7f0b278d4c88564c3a3b46180e476edcb2b783f253f3eec3b36f8fd4f"),
            s: b256!("467a881937edf2faf76e2e497085caf370c9689a1d83b245030757f70a1f64de"),
            v: 28,
        };

        //* When
        let result = verify(&domain, &attestation, &address, request, response);

        //* Then
        assert_eq!(result, Ok(()));
    }

    #[test]
    fn create_and_sign_an_attestation() {
        //* Given
        let domain = domain();
        let (address, signer) = signer();
        let deployment = DEPLOYMENT;

        let request = "foo";
        let response = "bar";

        //* When
        let attestation = create(&domain, &signer, &deployment, request, response);

        //* Then
        let result = verify(&domain, &attestation, &address, request, response);
        assert_eq!(result, Ok(()));
    }
}