ADD-01 MitigationConfirmed

[c4-bot-5]

Lines of code

Vulnerability details

Issue Report

ADD-01: Gas Fixes 1

Details

Issue#195

Issue#137

The following gas optimizations were identified for integration to the codebase to save gas:

[G-02] Optimization Proposal for Withdraw Function in MagicSpend Contract

[G-04] Check withdrawAmount - maxCost for greater than 0 if 0 it can save 1 Gsreset (~2900 Gas) and 1 Gcoldsload (Saves ~5000 Gas)

[G-06] Switch the order of if statement to fail early saves 1 function call half of the times where function have SLOAD (Saves ~2100 Gas Half of the times)

Mitigation

PR#18

• G-02: Validations are now reordered in the withdraw function to check signature fisrt and fail early before the _validateRequest gas intensive call which saves more gas.

Loc:

function withdraw(WithdrawRequest memory withdrawRequest) external {
        if (block.timestamp > withdrawRequest.expiry) {
            revert Expired();
        }

        if (!isValidWithdrawSignature(msg.sender, withdrawRequest)) {
            revert InvalidSignature();
        }
        
        _validateRequest(msg.sender, withdrawRequest);

        // reserve funds for gas, will credit user with difference in post op
        _withdraw(withdrawRequest.asset, msg.sender, withdrawRequest.amount);
    }

• G-04: Additional check was added to function in light of G-04 that checks if withdrawAmt is greater than maxCost before updating mapping. This indeed saves gas.

Loc:

if (withdrawAmount > maxCost) {
            _withdrawable[userOp.sender] += withdrawAmount - maxCost;
        }

• G-06: if statements reorganized which saves gas when calling this function.

Loc:

function withdraw(WithdrawRequest memory withdrawRequest) external {
        _validateRequest(msg.sender, withdrawRequest);

        if (block.timestamp > withdrawRequest.expiry) {
            revert Expired();
        }

        if (!isValidWithdrawSignature(msg.sender, withdrawRequest)) {
            revert InvalidSignature();
        }

        // reserve funds for gas, will credit user with difference in post op
        _withdraw(withdrawRequest.asset, msg.sender, withdrawRequest.amount);
    }

Conclusion

G-02, G-04, G-06 optimizations implemented successfully.

[c4-judge]

3docSec marked the issue as confirmed for report

[c4-judge]

3docSec marked the issue as satisfactory