M-01 MitigationConfirmed

[c4-bot-3]

Lines of code

Vulnerability details

Comments

In the original MagicSpend implementation there were insufficient checks that the MagicSpend contract had enough ETH to cover all the withdrawal requests in a UserOps bundle.

Mitigation

To mitigate this _validateRequest (called inside of validatePaymasterUserOp) allows requests to only request a fraction of the contracts ether balance meaning maxWithdrawDenominator amount of requests could be processed in a UserOps bundle without the contract unexpectedly running out of funds to cover withdrawals.

Conclusion

The mitigations made should fix this issue, providing maxWithdrawDenominator is set to a high enough value to cover the maximum possible user operations that can put into a single UserOps bundle.

However as the withdraw function also calls _validateRequest it is necessary that the contract has maxWithdrawDenominator times more than the maximum withdraw amount that can be signed for else their otherwise valid WithdrawRequest's will revert.

[c4-judge]

3docSec marked the issue as satisfactory