CVE-2020-37287

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Impact

When we pass a multi-dimensional array (like [[1, 2], [3, 4]]) as an argument to internal/external functions we get incorrect output. This is due to a stack management issue, because it was assumed that the size of each subtype of an array/struct is 32, which is not always correct.

Example code:

@internal
def test_input(arr: int128[2][1], i: int128) -> (int128[2][1], int128):
    return arr, i

@external
def test_values(arr: int128[2][1], i: int128) -> (int128[2][1], int128):
    return self.test_input(arr, i)

Please see #2183 for further information

Patches

This problem was fixed in #2184, and released as a part of v0.2.6.

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Impact

When we pass a multi-dimensional array (like [[1, 2], [3, 4]]) as an argument to internal/external functions we get incorrect output. This is due to a stack management issue, because it was assumed that the size of each subtype of an array/struct is 32, which is not always correct.

Example code:

@internal
def test_input(arr: int128[2][1], i: int128) -> (int128[2][1], int128):
    return arr, i

@external
def test_values(arr: int128[2][1], i: int128) -> (int128[2][1], int128):
    return self.test_input(arr, i)

Please see #2183 for further information

Patches

This problem was fixed in #2184, and released as a part of v0.2.6.