rpc/types: CheckTxFee doesn't check if gasPrice is nil

[odeke-em]

Is there an existing issue for this?

• I have searched the existing issues

What happened?

While security auditing this code I noticed that this code doesn't return an error

package types                   

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

there should be an error returned

Evmos Version

main

How to reproduce?

Run the repro produced

Fix

diff --git a/rpc/types/utils.go b/rpc/types/utils.go
index 964d1dcc..0a6676f3 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 == nil {
+		return errors.New("gasPrice is nil")
+	}
 	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))

[linear]

ENG-2550 rpc/types: CheckTxFee doesn't check if gasPrice is nil