verify messages delivery proofs (#482)

bridges/bin/millau/runtime/src/rialto_messages.rs

@@ -30,7 +30,6 @@ use frame_support::{
 	RuntimeDebug,
 };
 use sp_core::storage::StorageKey;
-use sp_trie::StorageProof;
 
 /// Storage key of the Millau -> Rialto message in the runtime storage.
 pub fn message_key(lane: &LaneId, nonce: MessageNonce) -> StorageKey {
@@ -63,6 +62,12 @@ pub type ToRialtoMessageVerifier = messages::source::FromThisChainMessageVerifie
 /// Message payload for Rialto -> Millau messages.
 pub type FromRialtoMessagePayload = messages::target::FromBridgedChainMessagePayload<WithRialtoMessageBridge>;
 
+/// Messages proof for Rialto -> Millau messages.
+type FromRialtoMessagesProof = messages::target::FromBridgedChainMessagesProof<WithRialtoMessageBridge>;
+
+/// Messages delivery proof for Millau -> Rialto messages.
+type ToRialtoMessagesDeliveryProof = messages::source::FromBridgedChainMessagesDeliveryProof<WithRialtoMessageBridge>;
+
 /// Call-dispatch based message dispatch for Rialto -> Millau messages.
 pub type FromRialtoMessageDispatch = messages::target::FromBridgedChainMessageDispatch<
 	WithRialtoMessageBridge,
@@ -152,7 +157,7 @@ impl TargetHeaderChain<ToRialtoMessagePayload, bp_rialto::AccountId> for Rialto
 	// - hash of the header this proof has been created with;
 	// - the storage proof or one or several keys;
 	// - id of the lane we prove state of.
-	type MessagesDeliveryProof = (bp_rialto::Hash, StorageProof, LaneId);
+	type MessagesDeliveryProof = ToRialtoMessagesDeliveryProof;
 
 	fn verify_message(payload: &ToRialtoMessagePayload) -> Result<(), Self::Error> {
 		if payload.weight > WithRialtoMessageBridge::maximal_dispatch_weight_of_message_on_bridged_chain() {
@@ -163,9 +168,9 @@ impl TargetHeaderChain<ToRialtoMessagePayload, bp_rialto::AccountId> for Rialto
 	}
 
 	fn verify_messages_delivery_proof(
-		_proof: Self::MessagesDeliveryProof,
-	) -> Result<(LaneId, InboundLaneData<bp_rialto::AccountId>), Self::Error> {
-		unimplemented!("https://github.com/paritytech/parity-bridges-common/issues/397")
+		proof: Self::MessagesDeliveryProof,
+	) -> Result<(LaneId, InboundLaneData<bp_millau::AccountId>), Self::Error> {
+		messages::source::verify_messages_delivery_proof::<WithRialtoMessageBridge, Runtime>(proof)
 	}
 }
 
@@ -176,7 +181,7 @@ impl SourceHeaderChain<bp_rialto::Balance> for Rialto {
 	// - the storage proof or one or several keys;
 	// - id of the lane we prove messages for;
 	// - inclusive range of messages nonces that are proved.
-	type MessagesProof = (bp_rialto::Hash, StorageProof, LaneId, MessageNonce, MessageNonce);
+	type MessagesProof = FromRialtoMessagesProof;
 
 	fn verify_messages_proof(
 		_proof: Self::MessagesProof,

bridges/bin/rialto/runtime/src/millau_messages.rs

@@ -30,7 +30,6 @@ use frame_support::{
 	RuntimeDebug,
 };
 use sp_core::storage::StorageKey;
-use sp_trie::StorageProof;
 
 /// Storage key of the Rialto -> Millau message in the runtime storage.
 pub fn message_key(lane: &LaneId, nonce: MessageNonce) -> StorageKey {
@@ -73,6 +72,9 @@ pub type FromMillauMessageDispatch = messages::target::FromBridgedChainMessageDi
 /// Messages proof for Millau -> Rialto messages.
 type FromMillauMessagesProof = messages::target::FromBridgedChainMessagesProof<WithMillauMessageBridge>;
 
+/// Messages delivery proof for Rialto -> Millau messages.
+type ToMillauMessagesDeliveryProof = messages::source::FromBridgedChainMessagesDeliveryProof<WithMillauMessageBridge>;
+
 /// Millau <-> Rialto message bridge.
 #[derive(RuntimeDebug, Clone, Copy)]
 pub struct WithMillauMessageBridge;
@@ -155,7 +157,7 @@ impl TargetHeaderChain<ToMillauMessagePayload, bp_millau::AccountId> for Millau
 	// - hash of the header this proof has been created with;
 	// - the storage proof of one or several keys;
 	// - id of the lane we prove state of.
-	type MessagesDeliveryProof = (bp_millau::Hash, StorageProof, LaneId);
+	type MessagesDeliveryProof = ToMillauMessagesDeliveryProof;
 
 	fn verify_message(payload: &ToMillauMessagePayload) -> Result<(), Self::Error> {
 		if payload.weight > WithMillauMessageBridge::maximal_dispatch_weight_of_message_on_bridged_chain() {
@@ -166,9 +168,9 @@ impl TargetHeaderChain<ToMillauMessagePayload, bp_millau::AccountId> for Millau
 	}
 
 	fn verify_messages_delivery_proof(
-		_proof: Self::MessagesDeliveryProof,
-	) -> Result<(LaneId, InboundLaneData<bp_millau::AccountId>), Self::Error> {
-		unimplemented!("https://github.com/paritytech/parity-bridges-common/issues/397")
+		proof: Self::MessagesDeliveryProof,
+	) -> Result<(LaneId, InboundLaneData<bp_rialto::AccountId>), Self::Error> {
+		messages::source::verify_messages_delivery_proof::<WithMillauMessageBridge, Runtime>(proof)
 	}
 }
 

bridges/bin/runtime-common/Cargo.toml

@@ -17,6 +17,7 @@ bp-message-lane = { path = "../../primitives/message-lane", default-features = f
 bp-runtime = { path = "../../primitives/runtime", default-features = false }
 pallet-bridge-call-dispatch = { path = "../../modules/call-dispatch", default-features = false }
 pallet-message-lane = { path = "../../modules/message-lane", default-features = false }
+pallet-substrate-bridge = { path = "../../modules/substrate", default-features = false }
 
 # Substrate dependencies
 
@@ -35,6 +36,7 @@ std = [
 	"frame-support/std",
 	"pallet-bridge-call-dispatch/std",
 	"pallet-message-lane/std",
+	"pallet-substrate-bridge/std",
 	"sp-runtime/std",
 	"sp-std/std",
 	"sp-trie/std",

bridges/bin/runtime-common/src/messages.rs

@@ -24,7 +24,7 @@ use bp_message_dispatch::MessageDispatch as _;
 use bp_message_lane::{
 	source_chain::LaneMessageVerifier,
 	target_chain::{DispatchMessage, MessageDispatch},
-	LaneId, MessageNonce,
+	InboundLaneData, LaneId, MessageNonce,
 };
 use bp_runtime::InstanceId;
 use codec::{Compact, Decode, Input};
@@ -77,7 +77,7 @@ pub trait ChainWithMessageLanes {
 	/// Hash used in the chain.
 	type Hash: Decode;
 	/// Accound id on the chain.
-	type AccountId;
+	type AccountId: Decode;
 	/// Public key of the chain account that may be used to verify signatures.
 	type Signer: Decode;
 	/// Signature type used on the chain.
@@ -105,6 +105,7 @@ pub(crate) type SignatureOf<C> = <C as ChainWithMessageLanes>::Signature;
 pub(crate) type WeightOf<C> = <C as ChainWithMessageLanes>::Weight;
 pub(crate) type BalanceOf<C> = <C as ChainWithMessageLanes>::Balance;
 pub(crate) type CallOf<C> = <C as ChainWithMessageLanes>::Call;
+pub(crate) type MessageLaneInstanceOf<C> = <C as ChainWithMessageLanes>::MessageLaneInstance;
 
 /// Sub-module that is declaring types required for processing This -> Bridged chain messages.
 pub mod source {
@@ -121,6 +122,16 @@ pub mod source {
 		BridgedChainOpaqueCall,
 	>;
 
+	/// Messages delivery proof from bridged chain:
+	///
+	/// - hash of finalized header;
+	/// - storage proof of inbound lane state;
+	/// - lane id.
+	pub type FromBridgedChainMessagesDeliveryProof<B> = (HashOf<BridgedChain<B>>, StorageProof, LaneId);
+
+	/// 'Parsed' message delivery proof - inbound lane id and its state.
+	pub type ParsedMessagesDeliveryProofFromBridgedChain<B> = (LaneId, InboundLaneData<AccountIdOf<ThisChain<B>>>);
+
 	/// Message verifier that requires submitter to pay minimal delivery and dispatch fee.
 	#[derive(RuntimeDebug)]
 	pub struct FromThisChainMessageVerifier<B>(PhantomData<B>);
@@ -188,6 +199,40 @@ pub mod source {
 				.and_then(|interest| fee.checked_add(&interest)))
 			.ok_or("Overflow when computing minimal required message delivery and dispatch fee")
 	}
+
+	/// Verify proof of This -> Bridged chain messages delivery.
+	pub fn verify_messages_delivery_proof<B: MessageBridge, ThisRuntime>(
+		proof: FromBridgedChainMessagesDeliveryProof<B>,
+	) -> Result<ParsedMessagesDeliveryProofFromBridgedChain<B>, &'static str>
+	where
+		ThisRuntime: pallet_substrate_bridge::Trait,
+		ThisRuntime: pallet_message_lane::Trait<MessageLaneInstanceOf<BridgedChain<B>>>,
+		HashOf<BridgedChain<B>>:
+			Into<bp_runtime::HashOf<<ThisRuntime as pallet_substrate_bridge::Trait>::BridgedChain>>,
+	{
+		let (bridged_header_hash, bridged_storage_proof, lane) = proof;
+		pallet_substrate_bridge::Module::<ThisRuntime>::parse_finalized_storage_proof(
+			bridged_header_hash.into(),
+			bridged_storage_proof,
+			|storage| {
+				// Messages delivery proof is just proof of single storage key read => any error
+				// is fatal.
+				let storage_inbound_lane_data_key = pallet_message_lane::storage_keys::inbound_lane_data_key::<
+					ThisRuntime,
+					MessageLaneInstanceOf<BridgedChain<B>>,
+				>(&lane);
+				let raw_inbound_lane_data = storage
+					.read_value(storage_inbound_lane_data_key.0.as_ref())
+					.map_err(|_| "Failed to read inbound lane state from storage proof")?
+					.ok_or("Inbound lane state is missing from the messages proof")?;
+				let inbound_lane_data = InboundLaneData::decode(&mut &raw_inbound_lane_data[..])
+					.map_err(|_| "Failed to decode inbound lane state from the proof")?;
+
+				Ok((lane, inbound_lane_data))
+			},
+		)
+		.map_err(<&'static str>::from)?
+	}
 }
 
 /// Sub-module that is declaring types required for processing Bridged -> This chain messages.