R4R: Catch overflows in gas wanted

PENDING.md

@@ -69,5 +69,6 @@ BUG FIXES
 
 * SDK
   * \#2967 Change ordering of `mint.BeginBlocker` and `distr.BeginBlocker`, recalculate inflation each block
+  * \#3071 Catch overflow on block gas meter
 
 * Tendermint

baseapp/baseapp.go

@@ -701,6 +701,11 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk
 		return
 	}
 
+	var startingGas uint64
+	if mode == runTxModeDeliver {
+		startingGas = ctx.BlockGasMeter().GasConsumed()
+	}
+
 	defer func() {
 		if r := recover(); r != nil {
 			switch rType := r.(type) {
@@ -726,6 +731,9 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk
 		if mode == runTxModeDeliver {
 			ctx.BlockGasMeter().ConsumeGas(
 				ctx.GasMeter().GasConsumedToLimit(), "block gas meter")
+			if ctx.BlockGasMeter().GasConsumed() < startingGas {
+				panic(sdk.ErrorGasOverflow{"tx gas summation"})
+			}
 		}
 	}()
 

types/errors.go

@@ -43,6 +43,7 @@ const (
 	CodeMemoTooLarge      CodeType = 13
 	CodeInsufficientFee   CodeType = 14
 	CodeTooManySignatures CodeType = 15
+	CodeGasOverflow       CodeType = 16
 
 	// CodespaceRoot is a codespace for error codes in this file only.
 	// Notice that 0 is an "unset" codespace, which can be overridden with
@@ -143,6 +144,9 @@ func ErrInsufficientFee(msg string) Error {
 func ErrTooManySignatures(msg string) Error {
 	return newErrorWithRootCodespace(CodeTooManySignatures, msg)
 }
+func ErrGasOverflow(msg string) Error {
+	return newErrorWithRootCodespace(CodeGasOverflow, msg)
+}
 
 //----------------------------------------
 // Error & sdkError

x/auth/stdtx.go

@@ -43,7 +43,7 @@ func (tx StdTx) ValidateBasic() sdk.Error {
 	stdSigs := tx.GetSignatures()
 
 	if tx.Fee.Gas > maxGasWanted {
-		return sdk.ErrInternal(fmt.Sprintf("invalid gas supplied; %d > %d", tx.Fee.Gas, maxGasWanted))
+		return sdk.ErrGasOverflow(fmt.Sprintf("invalid gas supplied; %d > %d", tx.Fee.Gas, maxGasWanted))
 	}
 	if !tx.Fee.Amount.IsNotNegative() {
 		return sdk.ErrInsufficientFee(fmt.Sprintf("invalid fee %s amount provided", tx.Fee.Amount))

x/auth/stdtx_test.go

@@ -127,7 +127,7 @@ func TestTxValidateBasic(t *testing.T) {
 
 	err = tx.ValidateBasic()
 	require.Error(t, err)
-	require.Equal(t, sdk.CodeInternal, err.Result().Code)
+	require.Equal(t, sdk.CodeGasOverflow, err.Result().Code)
 
 	// require to pass when above criteria are matched
 	privs, accNums, seqs = []crypto.PrivKey{priv1, priv2}, []uint64{0, 1}, []uint64{0, 0}