Add transaction cost pre-validation (polkadot-evm#465)

Author: tgmichel

frame/ethereum/src/lib.rs

@@ -190,6 +190,27 @@ pub mod pallet {
 
 		fn validate_unsigned(_source: TransactionSource, call: &Self::Call) -> TransactionValidity {
 			if let Call::transact(transaction) = call {
+				// We must ensure a transaction can pay the cost of its data bytes.
+				// If it can't it should not be included in a block.
+				let mut gasometer = evm::gasometer::Gasometer::new(
+					transaction.gas_limit.low_u64(),
+					<T as pallet_evm::Config>::config(),
+				);
+				let transaction_cost = match transaction.action {
+					TransactionAction::Call(_) => {
+						evm::gasometer::call_transaction_cost(&transaction.input)
+					}
+					TransactionAction::Create => {
+						evm::gasometer::create_transaction_cost(&transaction.input)
+					}
+				};
+				if gasometer.record_transaction(transaction_cost).is_err() {
+					return InvalidTransaction::Custom(
+						TransactionValidationError::InvalidGasLimit as u8,
+					)
+					.into();
+				}
+
 				if let Some(chain_id) = transaction.signature.chain_id() {
 					if chain_id != T::ChainId::get() {
 						return InvalidTransaction::Custom(

ts-tests/tests/test-transaction-cost.ts

@@ -0,0 +1,21 @@
+import { expect } from "chai";
+import { step } from "mocha-steps";
+
+import { describeWithFrontier, customRequest } from "./util";
+
+describeWithFrontier("Frontier RPC (Transaction cost)", (context) => {
+
+	step("should take transaction cost into account and not submit it to the pool", async function () {
+		// Simple transfer with gas limit 0 manually signed to prevent web3 from rejecting client-side.
+		const tx = await customRequest(context.web3, "eth_sendRawTransaction", [
+			"0xf86180843b9aca00809412cb274aad8251c875c0bf6872b67d9983e53fdd01801ca00e28ba2dd3c5a3fd467\
+			d4afd7aefb4a34b373314fff470bb9db743a84d674a0aa06e5994f2d07eafe1c37b4ce5471caecec29011f6f5b\
+			f0b1a552c55ea348df35f",
+		]);
+		let msg =
+			"submit transaction to pool failed: Pool(InvalidTransaction(InvalidTransaction::Custom(3)))";
+		expect(tx.error).to.include({
+			message: msg,
+		});
+	});
+});