cmd, eth, internal, les: add gasprice cap

cmd/geth/main.go

@@ -186,6 +186,7 @@ var (
 		utils.IPCPathFlag,
 		utils.InsecureUnlockAllowedFlag,
 		utils.RPCGlobalGasCap,
+		utils.RPCGlobalTxFeeCap,
 	}
 
 	whisperFlags = []cli.Flag{

cmd/geth/usage.go

@@ -176,6 +176,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.GraphQLCORSDomainFlag,
 			utils.GraphQLVirtualHostsFlag,
 			utils.RPCGlobalGasCap,
+			utils.RPCGlobalTxFeeCap,
 			utils.JSpathFlag,
 			utils.ExecFlag,
 			utils.PreloadJSFlag,

cmd/utils/flags.go

@@ -478,6 +478,11 @@ var (
 		Name:  "rpc.gascap",
 		Usage: "Sets a cap on gas that can be used in eth_call/estimateGas",
 	}
+	RPCGlobalTxFeeCap = cli.Float64Flag{
+		Name:  "rpc.txfeecap",
+		Usage: "Sets a cap on transaction fee(in ether) that can be used in sendTransaction/sendRawTransaction(zero for disable)",
+		Value: eth.DefaultConfig.RPCTxFeeCap,
+	}
 	// Logging and debug settings
 	EthStatsURLFlag = cli.StringFlag{
 		Name:  "ethstats",
@@ -1560,6 +1565,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *eth.Config) {
 	if ctx.GlobalIsSet(RPCGlobalGasCap.Name) {
 		cfg.RPCGasCap = new(big.Int).SetUint64(ctx.GlobalUint64(RPCGlobalGasCap.Name))
 	}
+	if ctx.GlobalIsSet(RPCGlobalTxFeeCap.Name) {
+		cfg.RPCTxFeeCap = ctx.GlobalFloat64(RPCGlobalTxFeeCap.Name)
+	}
 	if ctx.GlobalIsSet(DNSDiscoveryFlag.Name) {
 		urls := ctx.GlobalString(DNSDiscoveryFlag.Name)
 		if urls == "" {

eth/api_backend.go

@@ -293,6 +293,10 @@ func (b *EthAPIBackend) RPCGasCap() *big.Int {
 	return b.eth.config.RPCGasCap
 }
 
+func (b *EthAPIBackend) RPCTxFeeCap() float64 {
+	return b.eth.config.RPCTxFeeCap
+}
+
 func (b *EthAPIBackend) BloomStatus() (uint64, uint64) {
 	sections, _, _ := b.eth.bloomIndexer.Sections()
 	return params.BloomBitsBlocks, sections

eth/config.go

@@ -64,6 +64,7 @@ var DefaultConfig = Config{
 		Blocks:     20,
 		Percentile: 60,
 	},
+	RPCTxFeeCap: 1, // 1 ether
 }
 
 func init() {
@@ -159,6 +160,10 @@ type Config struct {
 	// RPCGasCap is the global gas cap for eth-call variants.
 	RPCGasCap *big.Int `toml:",omitempty"`
 
+	// RPCTxFeeCap is the global transaction fee(price * gaslimit) cap for
+	// send-transction variants. The unit is ether.
+	RPCTxFeeCap float64 `toml:",omitempty"`
+
 	// Checkpoint is a hardcoded checkpoint which can be nil.
 	Checkpoint *params.TrustedCheckpoint `toml:",omitempty"`
 

internal/ethapi/api.go

@@ -1520,6 +1520,13 @@ func (args *SendTxArgs) toTransaction() *types.Transaction {
 
 // SubmitTransaction is a helper function that submits tx to txPool and logs a message.
 func SubmitTransaction(ctx context.Context, b Backend, tx *types.Transaction) (common.Hash, error) {
+	// If the transaction fee cap is already specified, ensure the
+	// fee of the given transaction is _reasonable_.
+	feeEth := new(big.Float).Quo(new(big.Float).SetInt(new(big.Int).Mul(tx.GasPrice(), new(big.Int).SetUint64(tx.Gas()))), new(big.Float).SetInt(big.NewInt(params.Ether)))
+	feeFloat, _ := feeEth.Float64()
+	if b.RPCTxFeeCap() != 0 && feeFloat > b.RPCTxFeeCap() {
+		return common.Hash{}, fmt.Errorf("txfee(%.2f ether) exceeds the maximum setting(%.2f ether)", feeFloat, b.RPCTxFeeCap())
+	}
 	if err := b.SendTx(ctx, tx); err != nil {
 		return common.Hash{}, err
 	}

internal/ethapi/backend.go

@@ -45,7 +45,8 @@ type Backend interface {
 	ChainDb() ethdb.Database
 	AccountManager() *accounts.Manager
 	ExtRPCEnabled() bool
-	RPCGasCap() *big.Int // global gas cap for eth_call over rpc: DoS protection
+	RPCGasCap() *big.Int  // global gas cap for eth_call over rpc: DoS protection
+	RPCTxFeeCap() float64 // global tx fee cap for all transaction related APIs
 
 	// Blockchain API
 	SetHead(number uint64)

les/api_backend.go

@@ -262,6 +262,10 @@ func (b *LesApiBackend) RPCGasCap() *big.Int {
 	return b.eth.config.RPCGasCap
 }
 
+func (b *LesApiBackend) RPCTxFeeCap() float64 {
+	return b.eth.config.RPCTxFeeCap
+}
+
 func (b *LesApiBackend) BloomStatus() (uint64, uint64) {
 	if b.eth.bloomIndexer == nil {
 		return 0, 0