Prevent negative gas price (iotexproject#1059)

Author: zjshen14

action/const.go

@@ -25,6 +25,8 @@ var (
 	ErrNonce = errors.New("invalid nonce")
 	// ErrBalance indicates the error of balance
 	ErrBalance = errors.New("invalid balance")
+	// ErrGasPrice indicates the error of gas price
+	ErrGasPrice = errors.New("invalid gas price")
 	// ErrVotee indicates the error of votee
 	ErrVotee = errors.New("votee is not a candidate")
 	// ErrHash indicates the error of action's hash

action/protocol/account/transfer.go

@@ -173,6 +173,10 @@ func (p *Protocol) validateTransfer(_ context.Context, act action.Action) error
 	if tsf.Amount().Sign() < 0 {
 		return errors.Wrap(action.ErrBalance, "negative value")
 	}
+	// Reject transfer of negative gas price
+	if tsf.GasPrice().Sign() < 0 {
+		return errors.Wrap(action.ErrGasPrice, "negative value")
+	}
 	// check if recipient's address is valid
 	if _, err := address.FromString(tsf.Recipient()); err != nil {
 		return errors.Wrapf(err, "error when validating recipient's address %s", tsf.Recipient())

action/protocol/account/transfer_test.go

@@ -149,4 +149,10 @@ func TestProtocol_ValidateTransfer(t *testing.T) {
 	err = protocol.Validate(context.Background(), tsf)
 	require.Error(err)
 	require.True(strings.Contains(err.Error(), "error when validating recipient's address"))
+	// Case IV: Negative gas fee
+	tsf, err = action.NewTransfer(uint64(1), big.NewInt(100), "2", nil,
+		uint64(100000), big.NewInt(-1))
+	require.NoError(err)
+	err = protocol.Validate(context.Background(), tsf)
+	require.Equal(action.ErrGasPrice, errors.Cause(err))
 }

action/protocol/execution/protocol.go

@@ -73,6 +73,10 @@ func (p *Protocol) Validate(_ context.Context, act action.Action) error {
 	if exec.Amount().Sign() < 0 {
 		return errors.Wrap(action.ErrBalance, "negative value")
 	}
+	// Reject execution of negative gas price
+	if exec.GasPrice().Sign() < 0 {
+		return errors.Wrap(action.ErrGasPrice, "negative value")
+	}
 	// check if contract's address is valid
 	if exec.Contract() != action.EmptyAddress {
 		if _, err := address.FromString(exec.Contract()); err != nil {

action/protocol/execution/protocol_test.go

@@ -717,4 +717,9 @@ func TestProtocol_Validate(t *testing.T) {
 	err = protocol.Validate(context.Background(), ex)
 	require.Error(err)
 	require.True(strings.Contains(err.Error(), "error when validating contract's address"))
+	// Case V: Negative gas price
+	ex, err = action.NewExecution("2", uint64(1), big.NewInt(100), uint64(0), big.NewInt(-1), []byte{})
+	require.NoError(err)
+	err = protocol.Validate(context.Background(), ex)
+	require.Equal(action.ErrGasPrice, errors.Cause(err))
 }

action/protocol/rewarding/admin.go

@@ -236,7 +236,7 @@ func (p *Protocol) assertAmount(amount *big.Int) error {
 	if amount.Cmp(big.NewInt(0)) >= 0 {
 		return nil
 	}
-	return errors.Errorf("reward amount %s shouldn't be negative", amount.String())
+	return errors.Errorf("amount %s shouldn't be negative", amount.String())
 }
 
 func (p *Protocol) assertZeroBlockHeight(height uint64) error {

action/protocol/rewarding/fund.go

@@ -62,6 +62,9 @@ func (p *Protocol) Deposit(
 	amount *big.Int,
 ) error {
 	raCtx := protocol.MustGetRunActionsCtx(ctx)
+	if err := p.assertAmount(amount); err != nil {
+		return err
+	}
 	if err := p.assertEnoughBalance(raCtx, sm, amount); err != nil {
 		return err
 	}
@@ -71,7 +74,9 @@ func (p *Protocol) Deposit(
 		return err
 	}
 	acc.Balance = big.NewInt(0).Sub(acc.Balance, amount)
-	accountutil.StoreAccount(sm, raCtx.Caller.String(), acc)
+	if err := accountutil.StoreAccount(sm, raCtx.Caller.String(), acc); err != nil {
+		return err
+	}
 	// Add balance to fund
 	f := fund{}
 	if err := p.state(sm, fundKey, &f); err != nil {

action/protocol/rewarding/fund_test.go

@@ -50,3 +50,15 @@ func TestProtocol_Fund(t *testing.T) {
 	}, false)
 
 }
+
+func TestDepositNegativeGasFee(t *testing.T) {
+	testProtocol(t, func(t *testing.T, ctx context.Context, stateDB factory.Factory, p *Protocol) {
+
+		r := protocol.Registry{}
+		r.Register(ProtocolID, p)
+
+		ws, err := stateDB.NewWorkingSet()
+		require.NoError(t, err)
+		require.Error(t, DepositGas(ctx, ws, big.NewInt(-1), &r))
+	}, false)
+}