json unmarshaller accepts (and overflows) oversized decimal input #184
Description
package main
import (
"github.com/holiman/uint256"
"encoding/json"
"fmt"
)
func main() {
var v1, v2 uint256.Int
// As hex
if err := json.Unmarshal([]byte("\"0x10000000000000000000000000000000000000000000000000000000000000001\""), &v1); err != nil {
fmt.Println(err)
}
// As decimal
if err := json.Unmarshal([]byte("115792089237316195423570985008687907853269984665640564039457584007913129639937"), &v2); err != nil {
return
}
fmt.Println("As string:", v2.String()) // Prints 1
}The decimal number being deserialized here is 2**256+1, which exceeds the width of uint256.Int. Ideally json.Unmarshal should return an error for any oversized input but instead it appears to overflow the number.
The same value as a hex value is correctly rejected.