Process finality proofs in solidity PoA -> Substrate contract

modules/ethereum-contract/builtin/Cargo.toml

@@ -10,11 +10,36 @@ edition = "2018"
 # General dependencies
 
 codec = { package = "parity-scale-codec", version = "1.0.0" }
-finality-grandpa = { version = "0.12.2", features = ["derive-codec"] }
-sp-blockchain = "2.0.0-alpha.5"
-sp-finality-grandpa = "2.0.0-alpha.5"
-sp-runtime = "2.0.0-alpha.5"
+ethereum-types = "0.9.1"
 
 # Runtime/chain specific dependencies
 
 bridge-node-runtime = { path = "../../../bin/node/runtime" }
+
+[dependencies.sp-blockchain]
+version = "2.0.0-alpha.6"
+rev = "c13ad41634d0bd7cf07897c2aa062b917d520520"
+git = "https://github.com/paritytech/substrate/"
+
+[dependencies.sp-finality-grandpa]
+version = "2.0.0-alpha.6"
+rev = "c13ad41634d0bd7cf07897c2aa062b917d520520"
+git = "https://github.com/paritytech/substrate/"
+
+[dependencies.sp-runtime]
+version = "2.0.0-alpha.6"
+rev = "c13ad41634d0bd7cf07897c2aa062b917d520520"
+git = "https://github.com/paritytech/substrate/"
+
+[dependencies.sc-finality-grandpa]
+version = "0.8.0-dev"
+rev = "c13ad41634d0bd7cf07897c2aa062b917d520520"
+git = "https://github.com/paritytech/substrate/"
+
+[dev-dependencies]
+hex = "0.4"
+
+[dev-dependencies.sp-core]
+version = "2.0.0-alpha.6"
+rev = "c13ad41634d0bd7cf07897c2aa062b917d520520"
+git = "https://github.com/paritytech/substrate/"

modules/ethereum-contract/builtin/src/lib.rs

@@ -14,25 +14,29 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
-use bridge_node_runtime::{BlockNumber, Hash, Header as RuntimeHeader};
-use codec::Decode;
+use bridge_node_runtime::{Block, BlockNumber, Hash, Header as RuntimeHeader};
+use codec::{Decode, Encode};
+use ethereum_types::U256;
 use sp_blockchain::Error as ClientError;
+use sp_finality_grandpa::{AuthorityList, ConsensusLog, GRANDPA_ENGINE_ID};
 
 /// Builtin errors.
 #[derive(Debug)]
 pub enum Error {
+	/// Failed to decode block number.
+	BlockNumberDecode,
 	/// Failed to decode Substrate header.
 	HeaderDecode(codec::Error),
 	/// Failed to decode best voters set.
-	BestVotersDecode(codec::Error),
+	BestSetDecode(codec::Error),
 	/// Failed to decode finality proof.
 	FinalityProofDecode(codec::Error),
 	/// Failed to verify justification.
 	JustificationVerify(ClientError),
 }
 
 /// Substrate header.
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub struct Header {
 	/// Header hash.
 	pub hash: Hash,
@@ -45,35 +49,272 @@ pub struct Header {
 }
 
 /// GRANDPA validators set change signal.
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub struct ValidatorsSetSignal {
 	/// Signal delay.
 	pub delay: BlockNumber,
 	/// New validators set.
 	pub validators: Vec<u8>,
 }
 
+/// Convert from U256 to BlockNumber. Fails if `U256` value isn't fitting within `BlockNumber`
+/// limits (the runtime referenced by this module uses u32 as `BlockNumber`).
+pub fn to_substrate_block_number(number: U256) -> Result<BlockNumber, Error> {
+	match number == number.low_u32().into() {
+		true => Ok(number.low_u32()),
+		false => Err(Error::BlockNumberDecode),
+	}
+}
+
+/// Convert from BlockNumber to U256.
+pub fn from_substrate_block_number(number: BlockNumber) -> Result<U256, Error> {
+	Ok(U256::from(number as u64))
+}
+
 /// Parse Substrate header.
 pub fn parse_substrate_header(raw_header: &[u8]) -> Result<Header, Error> {
 	RuntimeHeader::decode(&mut &raw_header[..])
 		.map(|header| Header {
 			hash: header.hash(),
 			parent_hash: header.parent_hash,
 			number: header.number,
-			signal: None, // TODO: parse me
+			signal: sp_runtime::traits::Header::digest(&header)
+				.log(|log| {
+					log.as_consensus().and_then(|(engine_id, log)| {
+						if engine_id == GRANDPA_ENGINE_ID {
+							Some(log)
+						} else {
+							None
+						}
+					})
+				})
+				.and_then(|log| ConsensusLog::decode(&mut &log[..]).ok())
+				.and_then(|log| match log {
+					ConsensusLog::ScheduledChange(scheduled_change) => Some(ValidatorsSetSignal {
+						delay: scheduled_change.delay,
+						validators: scheduled_change.next_authorities.encode(),
+					}),
+					_ => None,
+				}),
 		})
 		.map_err(Error::HeaderDecode)
 }
 
 /// Verify GRANDPA finality proof.
 pub fn verify_substrate_finality_proof(
-	_best_set_id: u64,
-	_raw_best_voters: &[u8],
-	_raw_best_header: &[u8],
-	_raw_headers: &[&[u8]],
-	_raw_finality_proof: &[u8],
-) -> Result<(usize, usize), Error> {
-	Err(Error::JustificationVerify(ClientError::Msg(
-		"Not yet implemented".into(),
-	))) // TODO: implement me
+	finality_target_number: BlockNumber,
+	finality_target_hash: Hash,
+	best_set_id: u64,
+	raw_best_set: &[u8],
+	raw_finality_proof: &[u8],
+) -> Result<(), Error> {
+	let best_set = AuthorityList::decode(&mut &raw_best_set[..]).map_err(Error::BestSetDecode)?;
+	sc_finality_grandpa::GrandpaJustification::<Block>::decode_and_verify_finalizes(
+		&raw_finality_proof,
+		(finality_target_hash, finality_target_number),
+		best_set_id,
+		&best_set.into_iter().collect(),
+	)
+	.map_err(Error::JustificationVerify)
+	.map(|_| ())
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use bridge_node_runtime::DigestItem;
+	use sp_core::crypto::Public;
+	use sp_finality_grandpa::{AuthorityId, ScheduledChange};
+	use sp_runtime::generic::Digest;
+
+	#[test]
+	fn to_substrate_block_number_succeeds() {
+		assert_eq!(to_substrate_block_number(U256::zero()).unwrap(), 0);
+		assert_eq!(
+			to_substrate_block_number(U256::from(std::u32::MAX as u64)).unwrap(),
+			0xFFFFFFFF
+		);
+	}
+
+	#[test]
+	fn to_substrate_block_number_fails() {
+		assert!(matches!(
+			to_substrate_block_number(U256::from(std::u32::MAX as u64 + 1)),
+			Err(Error::BlockNumberDecode)
+		));
+	}
+
+	#[test]
+	fn from_substrate_block_number_succeeds() {
+		assert_eq!(from_substrate_block_number(0).unwrap(), U256::zero());
+		assert_eq!(
+			from_substrate_block_number(std::u32::MAX).unwrap(),
+			U256::from(std::u32::MAX)
+		);
+	}
+
+	#[test]
+	fn substrate_header_without_signal_parsed() {
+		let raw_header = RuntimeHeader {
+			parent_hash: [0u8; 32].into(),
+			number: 0,
+			state_root: "b2fc47904df5e355c6ab476d89fbc0733aeddbe302f0b94ba4eea9283f7e89e7"
+				.parse()
+				.unwrap(),
+			extrinsics_root: "03170a2e7597b7b7e3d84c05391d139a62b157e78786d8c082f29dcf4c111314"
+				.parse()
+				.unwrap(),
+			digest: Default::default(),
+		}
+		.encode();
+		assert_eq!(
+			raw_header,
+			hex::decode("000000000000000000000000000000000000000000000000000000000000000000b2fc47904df5e355c6ab476d89fbc0733aeddbe302f0b94ba4eea9283f7e89e703170a2e7597b7b7e3d84c05391d139a62b157e78786d8c082f29dcf4c11131400").unwrap(),
+		);
+
+		assert_eq!(
+			parse_substrate_header(&raw_header).unwrap(),
+			Header {
+				hash: "afbbeb92bf6ff14f60bdef0aa89f043dd403659ae82665238810ace0d761f6d0"
+					.parse()
+					.unwrap(),
+				parent_hash: Default::default(),
+				number: 0,
+				signal: None,
+			},
+		);
+	}
+
+	#[test]
+	fn substrate_header_with_signal_parsed() {
+		let authorities = vec![
+			(AuthorityId::from_slice(&[1; 32]), 101),
+			(AuthorityId::from_slice(&[3; 32]), 103),
+		];
+		let mut digest = Digest::default();
+		digest.push(DigestItem::Consensus(
+			GRANDPA_ENGINE_ID,
+			ConsensusLog::ScheduledChange(ScheduledChange {
+				next_authorities: authorities.clone(),
+				delay: 8,
+			})
+			.encode(),
+		));
+
+		let raw_header = RuntimeHeader {
+			parent_hash: "c0ac300d4005141ea690f3df593e049739c227316eb7f05052f3ee077388b68b"
+				.parse()
+				.unwrap(),
+			number: 8,
+			state_root: "822d6b412033aa9ac8e1722918eec5f25633529225754b3d4149982f5cacd4aa"
+				.parse()
+				.unwrap(),
+			extrinsics_root: "e7b07c0ce2799416ce7877b9cefc7f596bea5e8813bb2a0abf760414073ca928"
+				.parse()
+				.unwrap(),
+			digest,
+		}
+		.encode();
+		assert_eq!(
+			raw_header,
+			hex::decode("c0ac300d4005141ea690f3df593e049739c227316eb7f05052f3ee077388b68b20822d6b412033aa9ac8e1722918eec5f25633529225754b3d4149982f5cacd4aae7b07c0ce2799416ce7877b9cefc7f596bea5e8813bb2a0abf760414073ca928040446524e4b59010108010101010101010101010101010101010101010101010101010101010101010165000000000000000303030303030303030303030303030303030303030303030303030303030303670000000000000008000000").unwrap(),
+		);
+
+		assert_eq!(
+			parse_substrate_header(&raw_header).unwrap(),
+			Header {
+				hash: "3dfebb280bd87a4640f89d7f2adecd62b88148747bff5b63af6e1634ee37a56e"
+					.parse()
+					.unwrap(),
+				parent_hash: "c0ac300d4005141ea690f3df593e049739c227316eb7f05052f3ee077388b68b"
+					.parse()
+					.unwrap(),
+				number: 8,
+				signal: Some(ValidatorsSetSignal {
+					delay: 8,
+					validators: authorities.encode(),
+				}),
+			},
+		);
+	}
+
+	/// Number of the example block with justification.
+	const EXAMPLE_JUSTIFIED_BLOCK_NUMBER: u32 = 8;
+	/// Hash of the example block with justification.
+	const EXAMPLE_JUSTIFIED_BLOCK_HASH: &'static str =
+		"a2f45892db86b2ad133ce57d81b7e4375bb7035ce9883e6b68c358164f343775";
+	/// Id of authorities set that have generated example justification. Could be computed by tracking
+	/// every set change in canonized headers.
+	const EXAMPLE_AUTHORITIES_SET_ID: u64 = 0;
+	/// Encoded authorities set that has generated example justification. Could be fetched from `ScheduledChange`
+	/// digest of the block that has scheduled this set OR by calling `GrandpaApi::grandpa_authorities()` at
+	/// appropriate block.
+	const EXAMPLE_AUTHORITIES_SET: &'static str = "1488dc3417d5058ec4b4503e0c12ea1a0a89be200fe98922423d4334014fa6b0ee0100000000000000d17c2d7823ebf260fd138f2d7e27d114c0145d968b5ff5006125f2414fadae690100000000000000439660b36c6c03afafca027b910b4fecf99801834c62a5e6006f27d978de234f01000000000000005e639b43e0052c47447dac87d6fd2b6ec50bdd4d0f614e4299c665249bbd09d901000000000000001dfe3e22cc0d45c70779c1095f7489a8ef3cf52d62fbd8c2fa38c9f1723502b50100000000000000";
+	/// Example justification. Could be fetched by calling 'chain_getBlock' RPC.
+	const EXAMPLE_JUSTIFICATION: &'static str = "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";
+
+	#[test]
+	fn substrate_header_parse_fails() {
+		assert!(matches!(parse_substrate_header(&[]), Err(_)));
+	}
+
+	#[test]
+	fn verify_substrate_finality_proof_succeeds() {
+		verify_substrate_finality_proof(
+			EXAMPLE_JUSTIFIED_BLOCK_NUMBER,
+			EXAMPLE_JUSTIFIED_BLOCK_HASH.parse().unwrap(),
+			EXAMPLE_AUTHORITIES_SET_ID,
+			&hex::decode(EXAMPLE_AUTHORITIES_SET).unwrap(),
+			&hex::decode(EXAMPLE_JUSTIFICATION).unwrap(),
+		)
+		.unwrap();
+	}
+
+	#[test]
+	fn verify_substrate_finality_proof_fails_when_wrong_block_is_finalized() {
+		verify_substrate_finality_proof(
+			4,
+			Default::default(),
+			EXAMPLE_AUTHORITIES_SET_ID,
+			&hex::decode(EXAMPLE_AUTHORITIES_SET).unwrap(),
+			&hex::decode(EXAMPLE_JUSTIFICATION).unwrap(),
+		)
+		.unwrap_err();
+	}
+
+	#[test]
+	fn verify_substrate_finality_proof_fails_when_wrong_set_is_provided() {
+		verify_substrate_finality_proof(
+			EXAMPLE_JUSTIFIED_BLOCK_NUMBER,
+			EXAMPLE_JUSTIFIED_BLOCK_HASH.parse().unwrap(),
+			EXAMPLE_AUTHORITIES_SET_ID,
+			&hex::decode("deadbeef").unwrap(),
+			&hex::decode(EXAMPLE_JUSTIFICATION).unwrap(),
+		)
+		.unwrap_err();
+	}
+
+	#[test]
+	fn verify_substrate_finality_proof_fails_when_wrong_set_id_is_provided() {
+		verify_substrate_finality_proof(
+			EXAMPLE_JUSTIFIED_BLOCK_NUMBER,
+			EXAMPLE_JUSTIFIED_BLOCK_HASH.parse().unwrap(),
+			42,
+			&hex::decode(EXAMPLE_AUTHORITIES_SET).unwrap(),
+			&hex::decode(EXAMPLE_JUSTIFICATION).unwrap(),
+		)
+		.unwrap_err();
+	}
+
+	#[test]
+	fn verify_substrate_finality_proof_fails_when_wrong_proof_is_provided() {
+		verify_substrate_finality_proof(
+			EXAMPLE_JUSTIFIED_BLOCK_NUMBER,
+			EXAMPLE_JUSTIFIED_BLOCK_HASH.parse().unwrap(),
+			0,
+			&hex::decode(EXAMPLE_AUTHORITIES_SET).unwrap(),
+			&hex::decode("deadbeef").unwrap(),
+		)
+		.unwrap_err();
+	}
 }

relays/ethereum/res/substrate-bridge-abi.json

@@ -79,19 +79,18 @@
 		"type": "function"
 	},
 	{
-		"inputs": [
-			{
-				"internalType": "bytes32",
-				"name": "headerHash",
-				"type": "bytes32"
-			}
-		],
-		"name": "isFinalityProofRequired",
+		"inputs": [],
+		"name": "incompleteHeaders",
 		"outputs": [
 			{
-				"internalType": "bool",
+				"internalType": "uint256[]",
 				"name": "",
-				"type": "bool"
+				"type": "uint256[]"
+			},
+			{
+				"internalType": "bytes32[]",
+				"name": "",
+				"type": "bytes32[]"
 			}
 		],
 		"stateMutability": "view",