Propagate message verification errors (#2114)

* Propagate message verification errors

* Replace parse_finalized_storage_proof() with storage_proof_checker()

* small fixes

* fix comment

bridges/primitives/messages/src/lib.rs

@@ -20,9 +20,15 @@
 // RuntimeApi generated functions
 #![allow(clippy::too_many_arguments)]
 
-use bp_runtime::{BasicOperatingMode, OperatingMode, RangeInclusiveExt};
+use bp_header_chain::HeaderChainError;
+use bp_runtime::{
+	messages::MessageDispatchResult, BasicOperatingMode, OperatingMode, RangeInclusiveExt,
+	StorageProofError,
+};
 use codec::{Decode, Encode, MaxEncodedLen};
-use frame_support::RuntimeDebug;
+use frame_support::{PalletError, RuntimeDebug};
+// Weight is reexported to avoid additional frame-support dependencies in related crates.
+pub use frame_support::weights::Weight;
 use scale_info::TypeInfo;
 use source_chain::RelayersRewards;
 use sp_core::TypeId;
@@ -32,10 +38,6 @@ pub mod source_chain;
 pub mod storage_keys;
 pub mod target_chain;
 
-use bp_runtime::messages::MessageDispatchResult;
-// Weight is reexported to avoid additional frame-support dependencies in related crates.
-pub use frame_support::weights::Weight;
-
 /// Messages pallet operating mode.
 #[derive(Encode, Decode, Clone, Copy, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
 #[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
@@ -414,6 +416,31 @@ pub enum BridgeMessagesCall<AccountId, MessagesProof, MessagesDeliveryProof> {
 	},
 }
 
+/// Error that happens during message verification.
+#[derive(Encode, Decode, RuntimeDebug, PartialEq, Eq, PalletError, TypeInfo)]
+pub enum VerificationError {
+	/// The message proof is empty.
+	EmptyMessageProof,
+	/// Error returned by the bridged header chain.
+	HeaderChain(HeaderChainError),
+	/// Error returned while reading/decoding inbound lane data from the storage proof.
+	InboundLaneStorage(StorageProofError),
+	/// The declared message weight is incorrect.
+	InvalidMessageWeight,
+	/// Declared messages count doesn't match actual value.
+	MessagesCountMismatch,
+	/// Error returned while reading/decoding message data from the storage proof.
+	MessageStorage(StorageProofError),
+	/// The message is too large.
+	MessageTooLarge,
+	/// Error returned while reading/decoding outbound lane data from the storage proof.
+	OutboundLaneStorage(StorageProofError),
+	/// Storage proof related error.
+	StorageProof(StorageProofError),
+	/// Custom error
+	Other(#[codec(skip)] &'static str),
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

bridges/primitives/messages/src/source_chain.rs

@@ -16,7 +16,7 @@
 
 //! Primitives of messages module, that are used on the source chain.
 
-use crate::{InboundLaneData, LaneId, MessageNonce, OutboundLaneData};
+use crate::{InboundLaneData, LaneId, MessageNonce, OutboundLaneData, VerificationError};
 
 use crate::UnrewardedRelayer;
 use bp_runtime::Size;
@@ -40,9 +40,6 @@ pub type RelayersRewards<AccountId> = BTreeMap<AccountId, MessageNonce>;
 /// source chain to the target chain. The `AccountId` type here means the account
 /// type used by the source chain.
 pub trait TargetHeaderChain<Payload, AccountId> {
-	/// Error type.
-	type Error: Debug;
-
 	/// Proof that messages have been received by target chain.
 	type MessagesDeliveryProof: Parameter + Size;
 
@@ -58,12 +55,12 @@ pub trait TargetHeaderChain<Payload, AccountId> {
 	/// 1MB. BTC nodes aren't accepting transactions that are larger than 1MB, so relayer
 	/// will be unable to craft valid transaction => this (and all subsequent) messages will
 	/// never be delivered.
-	fn verify_message(payload: &Payload) -> Result<(), Self::Error>;
+	fn verify_message(payload: &Payload) -> Result<(), VerificationError>;
 
 	/// Verify messages delivery proof and return lane && nonce of the latest received message.
 	fn verify_messages_delivery_proof(
 		proof: Self::MessagesDeliveryProof,
-	) -> Result<(LaneId, InboundLaneData<AccountId>), Self::Error>;
+	) -> Result<(LaneId, InboundLaneData<AccountId>), VerificationError>;
 }
 
 /// Lane message verifier.
@@ -75,9 +72,6 @@ pub trait TargetHeaderChain<Payload, AccountId> {
 ///
 /// Any fee requirements should also be enforced here.
 pub trait LaneMessageVerifier<SenderOrigin, Payload> {
-	/// Error type.
-	type Error: Debug + Into<&'static str>;
-
 	/// Verify message payload and return Ok(()) if message is valid and allowed to be sent over the
 	/// lane.
 	fn verify_message(
@@ -85,7 +79,7 @@ pub trait LaneMessageVerifier<SenderOrigin, Payload> {
 		lane: &LaneId,
 		outbound_data: &OutboundLaneData,
 		payload: &Payload,
-	) -> Result<(), Self::Error>;
+	) -> Result<(), VerificationError>;
 }
 
 /// Manages payments that are happening at the source chain during delivery confirmation
@@ -169,31 +163,27 @@ const ALL_OUTBOUND_MESSAGES_REJECTED: &str =
 	"This chain is configured to reject all outbound messages";
 
 impl<Payload, AccountId> TargetHeaderChain<Payload, AccountId> for ForbidOutboundMessages {
-	type Error = &'static str;
-
 	type MessagesDeliveryProof = ();
 
-	fn verify_message(_payload: &Payload) -> Result<(), Self::Error> {
-		Err(ALL_OUTBOUND_MESSAGES_REJECTED)
+	fn verify_message(_payload: &Payload) -> Result<(), VerificationError> {
+		Err(VerificationError::Other(ALL_OUTBOUND_MESSAGES_REJECTED))
 	}
 
 	fn verify_messages_delivery_proof(
 		_proof: Self::MessagesDeliveryProof,
-	) -> Result<(LaneId, InboundLaneData<AccountId>), Self::Error> {
-		Err(ALL_OUTBOUND_MESSAGES_REJECTED)
+	) -> Result<(LaneId, InboundLaneData<AccountId>), VerificationError> {
+		Err(VerificationError::Other(ALL_OUTBOUND_MESSAGES_REJECTED))
 	}
 }
 
 impl<SenderOrigin, Payload> LaneMessageVerifier<SenderOrigin, Payload> for ForbidOutboundMessages {
-	type Error = &'static str;
-
 	fn verify_message(
 		_submitter: &SenderOrigin,
 		_lane: &LaneId,
 		_outbound_data: &OutboundLaneData,
 		_payload: &Payload,
-	) -> Result<(), Self::Error> {
-		Err(ALL_OUTBOUND_MESSAGES_REJECTED)
+	) -> Result<(), VerificationError> {
+		Err(VerificationError::Other(ALL_OUTBOUND_MESSAGES_REJECTED))
 	}
 }
 

bridges/primitives/messages/src/target_chain.rs

@@ -16,7 +16,9 @@
 
 //! Primitives of messages module, that are used on the target chain.
 
-use crate::{LaneId, Message, MessageKey, MessageNonce, MessagePayload, OutboundLaneData};
+use crate::{
+	LaneId, Message, MessageKey, MessageNonce, MessagePayload, OutboundLaneData, VerificationError,
+};
 
 use bp_runtime::{messages::MessageDispatchResult, Size};
 use codec::{Decode, Encode, Error as CodecError};
@@ -58,9 +60,6 @@ pub struct DispatchMessage<DispatchPayload> {
 /// can't change. Wrong implementation may lead to invalid lane states (i.e. lane
 /// that's stuck) and/or processing messages without paying fees.
 pub trait SourceHeaderChain {
-	/// Error type.
-	type Error: Debug;
-
 	/// Proof that messages are sent from source chain. This may also include proof
 	/// of corresponding outbound lane states.
 	type MessagesProof: Parameter + Size;
@@ -79,7 +78,7 @@ pub trait SourceHeaderChain {
 	fn verify_messages_proof(
 		proof: Self::MessagesProof,
 		messages_count: u32,
-	) -> Result<ProvedMessages<Message>, Self::Error>;
+	) -> Result<ProvedMessages<Message>, VerificationError>;
 }
 
 /// Called when inbound message is received.
@@ -164,21 +163,20 @@ pub struct ForbidInboundMessages<MessagesProof, DispatchPayload>(
 	PhantomData<(MessagesProof, DispatchPayload)>,
 );
 
-/// Error message that is used in `ForbidOutboundMessages` implementation.
+/// Error message that is used in `ForbidInboundMessages` implementation.
 const ALL_INBOUND_MESSAGES_REJECTED: &str =
 	"This chain is configured to reject all inbound messages";
 
 impl<MessagesProof: Parameter + Size, DispatchPayload> SourceHeaderChain
 	for ForbidInboundMessages<MessagesProof, DispatchPayload>
 {
-	type Error = &'static str;
 	type MessagesProof = MessagesProof;
 
 	fn verify_messages_proof(
 		_proof: Self::MessagesProof,
 		_messages_count: u32,
-	) -> Result<ProvedMessages<Message>, Self::Error> {
-		Err(ALL_INBOUND_MESSAGES_REJECTED)
+	) -> Result<ProvedMessages<Message>, VerificationError> {
+		Err(VerificationError::Other(ALL_INBOUND_MESSAGES_REJECTED))
 	}
 }