reject tx with too large gas limit

rpc/ethereum/backend/backend.go

@@ -607,6 +607,13 @@ func (e *EVMBackend) SendTransaction(args types.SendTxArgs) (common.Hash, error)
 
 	msg := args.ToTransaction()
 
+	// hotfix, reject tx with too high gas limit
+	// FIXME remove after real fix is used: https://github.com/tharsis/ethermint/pull/751
+	if msg.GetGas() > types.RPCTxGasCap {
+		e.logger.Debug("gas limit too large", "gasLimit", fmt.Sprintf("%d", msg.GetGas()))
+		return common.Hash{}, fmt.Errorf("gas limit too large %d", msg.GetGas())
+	}
+
 	if err := msg.ValidateBasic(); err != nil {
 		e.logger.Debug("tx failed basic validation", "error", err.Error())
 		return common.Hash{}, err

rpc/ethereum/namespaces/eth/api.go

@@ -374,6 +374,13 @@ func (e *PublicAPI) SendRawTransaction(data hexutil.Bytes) (common.Hash, error)
 		return common.Hash{}, fmt.Errorf("invalid transaction type %T", tx)
 	}
 
+	// hotfix, reject tx with too high gas limit
+	// FIXME remove after real fix is used: https://github.com/tharsis/ethermint/pull/751
+	if ethereumTx.GetGas() > rpctypes.RPCTxGasCap {
+		e.logger.Debug("gas limit too large", "gasLimit", fmt.Sprintf("%d", ethereumTx.GetGas()))
+		return common.Hash{}, fmt.Errorf("gas limit too large %d", ethereumTx.GetGas())
+	}
+
 	if err := ethereumTx.ValidateBasic(); err != nil {
 		e.logger.Debug("tx failed basic validation", "error", err.Error())
 		return common.Hash{}, err

rpc/ethereum/types/types.go

@@ -11,6 +11,12 @@ import (
 	evmtypes "github.com/tharsis/ethermint/x/evm/types"
 )
 
+// RPCTxGasCap defines a gas limit threshold for transaction at rpc level
+// The transactions with gas limit larger than this will be rejected.
+// The number should be enough for the mainstream use cases.
+// FIXME The limitation is a temporary fix, should be removed after real fix is used: https://github.com/tharsis/ethermint/pull/751
+const RPCTxGasCap = 10000000
+
 // Copied the Account and StorageResult types since they are registered under an
 // internal pkg on geth.