accounts/abi: fix unpacking of negative int256 (#17583)

This commit is contained in:
Diep Pham 2018-09-04 22:53:28 +07:00 committed by Felix Lange
parent beee7a52e0
commit 42bd67bd6f
2 changed files with 30 additions and 3 deletions

View File

@ -25,8 +25,17 @@ import (
"github.com/ethereum/go-ethereum/common"
)
var (
maxUint256 = big.NewInt(0).Add(
big.NewInt(0).Exp(big.NewInt(2), big.NewInt(256), nil),
big.NewInt(-1))
maxInt256 = big.NewInt(0).Add(
big.NewInt(0).Exp(big.NewInt(2), big.NewInt(255), nil),
big.NewInt(-1))
)
// reads the integer based on its kind
func readInteger(kind reflect.Kind, b []byte) interface{} {
func readInteger(typ byte, kind reflect.Kind, b []byte) interface{} {
switch kind {
case reflect.Uint8:
return b[len(b)-1]
@ -45,7 +54,20 @@ func readInteger(kind reflect.Kind, b []byte) interface{} {
case reflect.Int64:
return int64(binary.BigEndian.Uint64(b[len(b)-8:]))
default:
return new(big.Int).SetBytes(b)
// the only case lefts for integer is int256/uint256.
// big.SetBytes can't tell if a number is negative, positive on itself.
// On EVM, if the returned number > max int256, it is negative.
ret := new(big.Int).SetBytes(b)
if typ == UintTy {
return ret
}
if ret.Cmp(maxInt256) > 0 {
ret.Add(maxUint256, big.NewInt(0).Neg(ret))
ret.Add(ret, big.NewInt(1))
ret.Neg(ret)
}
return ret
}
}
@ -179,7 +201,7 @@ func toGoType(index int, t Type, output []byte) (interface{}, error) {
case StringTy: // variable arrays are written at the end of the return bytes
return string(output[begin : begin+end]), nil
case IntTy, UintTy:
return readInteger(t.Kind, returnOutput), nil
return readInteger(t.T, t.Kind, returnOutput), nil
case BoolTy:
return readBool(returnOutput)
case AddressTy:

View File

@ -117,6 +117,11 @@ var unpackTests = []unpackTest{
enc: "0000000000000000000000000000000000000000000000000000000000000001",
want: big.NewInt(1),
},
{
def: `[{"type": "int256"}]`,
enc: "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
want: big.NewInt(-1),
},
{
def: `[{"type": "address"}]`,
enc: "0000000000000000000000000100000000000000000000000000000000000000",