Due to missing overflow check for loop variables, by assigning the iterator of a loop to a variable, it is possible to overflow the type of the latter.
In the following example, calling test
returns 354
, meaning that the variable a
did store 354
a value out of bound for the type uint8
.
@external
def test() -> uint16:
x:uint8 = 255
a:uint8 = 0
for i in range(x, x+100):
a = i
return convert(a,uint16)
The issue seems to happen only in loops of type for i in range(a, a + N)
as in loops of type for i in range(start, stop)
and for i in range(stop)
, the compiler is able to raise a TypeMismatch
when trying to overflow the variable.
thanks to @trocher for reporting
patched in 3de1415ee77a9244eb04bdb695e249d3ec9ed868
{ "nvd_published_at": "2023-05-11T21:15:10Z", "cwe_ids": [ "CWE-190" ], "severity": "HIGH", "github_reviewed": true, "github_reviewed_at": "2023-05-12T20:21:35Z" }