Fix EIP 712 - Data of the struct should be concatenated after type hash (#1054)

Author: MauroToscano

batcher/aligned-sdk/src/core/types.rs

@@ -232,21 +232,17 @@ impl Eip712 for NoncedVerificationData {
 
         let mut hasher = Keccak256::new();
 
-        // As per the EIP, first we generate the type hash
         // hashStruct(s : 𝕊) = keccak256(typeHash ‖ encodeData(s))
+
+        // We first generate the type hash
         hasher.update(NONCED_VERIFICATION_DATA_TYPE);
         let type_hash = hasher.finalize_reset();
 
-        // Then hash is resetted, so we start hashing the second term of the encodedData(s)
+        // Then we hash it with the rest of the data in the struct
+        hasher.update(type_hash);
         hasher.update(verification_data_hash);
         hasher.update(nonce_bytes);
         hasher.update(max_fee_bytes);
-        let encoded_data_hash = hasher.finalize_reset();
-
-        // Now we do the actual final
-        // keccak256(typeHash ‖ encodeData(s))
-        hasher.update(type_hash);
-        hasher.update(encoded_data_hash);
         let hash_struct = hasher.finalize_reset();
 
         Ok(hash_struct.into())

contracts/scripts/anvil/state/alignedlayer-deployed-anvil-state.json

@@ -79,6 +79,8 @@ contract BatcherPaymentService is
         noncedVerificationDataTypeHash = _noncedVerificationDataTypeHash;
     }
 
+    // Defined in types.rs
+    // keccak256("NoncedVerificationData(bytes32 verification_data_hash,uint256 nonce,uint256 max_fee)")
     function initializeNoncedVerificationDataTypeHash(
         bytes32 _noncedVerificationDataTypeHash
     ) public reinitializer(2) onlyOwner {
@@ -280,15 +282,12 @@ contract BatcherPaymentService is
             revert InvalidMaxFee(signatureData.maxFee, feePerProof);
         }
 
-        bytes32 encodedDataHash = keccak256(
-            abi.encode(
-                leaf,
-                signatureData.nonce,
-                signatureData.maxFee
-            )
-        );
-
-        bytes32 structHash = keccak256(abi.encode(noncedVerificationDataTypeHash, encodedDataHash));
+        bytes32 structHash =  keccak256(abi.encode(
+            noncedVerificationDataTypeHash,
+            leaf,
+            signatureData.nonce,
+            signatureData.maxFee
+        ));
 
         bytes32 hash = _hashTypedDataV4(structHash);