rpc/types: CheckTxFee should catch non-positive values and return an error

[odeke-em]

Is there an existing issue for this?

• I have searched the existing issues

What happened?

This code doesn't return an error

package types

import (
	"math/big"
	"testing"
)

func TestCheckTxInvalids(t *testing.T) {
	gp := big.NewInt(-1)
	if err := CheckTxFee(gp, 10, 100); err == nil {
		t.Fatal("expecting a non-nil error")
	}
}

Evmos Version

main

How to reproduce?

Please run my reproduction

Fix

diff --git a/rpc/types/utils.go b/rpc/types/utils.go
index 964d1dcc..5270c5ad 100644
--- a/rpc/types/utils.go
+++ b/rpc/types/utils.go
@@ -4,6 +4,7 @@ package types
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"math/big"
 	"strings"
@@ -253,6 +254,9 @@ func CheckTxFee(gasPrice *big.Int, gas uint64, cap float64) error {
 	if cap == 0 {
 		return nil
 	}
+	if gasPrice.Sign() != 1 {
+		return errors.New("gasPrice must be positive!")
+	}
 	totalfee := new(big.Float).SetInt(new(big.Int).Mul(gasPrice, new(big.Int).SetUint64(gas)))
 	// 1 evmos in 10^18 aevmos
 	oneToken := new(big.Float).SetInt(big.NewInt(params.Ether))

/cc @fedekunze

[linear]

ENG-2551 rpc/types: CheckTxFee should catch non-positive values and return an error

[odeke-em]

Actually this looks like the absence of the enforcement that I raised is a major violation of the Ethereum specification per https://ethereum.github.io/yellowpaper/paper.pdf

[MalteHerrmann]

Closing this as per the comment on the linked PR.