Use SafeMath to prevent the underflow in handleStratOrderAtID function

[code423n4]

Lines of code

https://github.com/code-423n4/2022-05-rubicon/blob/8c312a63a91193c6a192a9aab44ff980fbfd7741/contracts/rubiconPools/BathPair.sol#L226-L227

Vulnerability details

Impact

Subtractions in handleStratOrderAtID function at BathPair.sol potentially cause underflown which cause unexpected behaviors.

Proof of Concept

Although SafeMath is used throughout the codebase, only the following codes do not follow this pattern.

https://github.com/code-423n4/2022-05-rubicon/blob/8c312a63a91193c6a192a9aab44ff980fbfd7741/contracts/rubiconPools/BathPair.sol#L226-L227

        uint256 askDelta = info.askPayAmt - offer1.pay_amt;
        uint256 bidDelta = info.bidPayAmt - offer2.pay_amt;

Tools Used

Static code analysis

Recommended Mitigation Steps

This part should also use SafeMath to prevent the underflow.

        uint256 askDelta = info.askPayAmt.sub(offer1.pay_amt);
        uint256 bidDelta = info.bidPayAmt.sub(offer2.pay_amt);

[KenzoAgada]

No attack path, probably should be low/informational severity.

[HickupHH3]

Lacking details, downgrading to QA.

[HickupHH3]

Part of warden's QA report: #204