koxuan - creating an AutoRoller will fail when using an adapter that uses a erc20 token with more than 18 decimals as target

[sherlock-admin]

koxuan

medium

creating an AutoRoller will fail when using an adapter that uses a erc20 token with more than 18 decimals as target

Summary

An arithmetic calculation in the construtor() function in AutoRoller.sol will cause an underflow and revert when creating a roller with an adapter that uses a erc20 token with more than 18 decimals as target.

Vulnerability Detail

uint256 scalingFactor = 10**(18 - decimals) underflows and reverts if decimals is more than 18

Impact

User will be unable to create AutoRoller with adapter that uses a erc20 token with more than 18 decimals as target.

Code Snippet

AutoRoller.sol#L138

        uint256 scalingFactor = 10**(18 - decimals);

Tool used

Manual Review

Recommendation

if else clause can mitigate this by handling erc20 tokens with more than 18 decimals

if (decimals > 18){
    // logic for handling more than 18 decimal points 
    // ie: scalingFactor = 1
} 
else{
    scalingFactor = 10**(18 - decimals);
}

[jparklev]

This is known behavior and is the same in our space pool (pattern originally taken from balancer)