First Flight #8: Math Master

Description

MathMasters::mulWad and MathMasters::mulWadUp revert when the multiplication overflows without considering the subsequent division. However, the result of the multiplication and division can be within the uint256 range in this case: $ x \cdot y > \text{type(uint256).max} > \frac{x \cdot y}{WAD} $

Impact

Likelihood: Medium

• Occurs whenever : $ x \cdot y > \text{type(uint256).max} > \frac{x \cdot y}{WAD}$ which is equivalent to :

Impact: Medium/Low

• If users are unaware of this behavior, the program will revert, leading to unexpected behavior in contracts using this library.

• Other libraries, such as Math by OpenZeppelin, manage this case, potentially causing confusion for users.

Proof of Concept

Recommended Mitigation

• Use a well-known and tested library like Math by OpenZeppelin.

• Alternatively, implement a mechanism inspired by existing libraries to handle large numbers when the result can be a valid number after division.