Beedle - Oracle free perpetual lending

Summary

The vulnerability in the FeeDistribution interface is that the Staking contract is not correctly implementing the inherited claim() function.

The problem is the following:

• The FeeDistribution interface defines the claim(address) function that must be implemented by contracts that inherit it.

• The Staking contract inherits from FeeDistribution but does not implement the claim(address) function as defined in the interface.

• Instead, Staking implements a different claim() function, which does not receive an address parameter.

Vulnerability Details

In short, it is a design vulnerability not to follow the interface standard, which can lead to errors and incompatibilities.

Impact

This can lead to the following problems:

• Any contract attempting to call claim(address) on an instance of Staking will receive an error, as the function does not exist.

• The reward claiming logic in Staking is completely different from what any other contract would expect when inheriting FeeDistribution.

• The advantage of using a standardised interface is lost, as Staking does not follow the standard.

Tools Used

Manual review

Recommendations

To fix this, Staking should implement the claim(address) function as defined in the FeeDistribution interface:

This ensures that the contract is compatible with others using the FeeDistribution interface and the standardised claim logic can be reused.