Mimo August 2022 contest - Chom's results

executeOperation is a crucial function but doesn't emit any events.

executeOperation on all file that require flash loan is a crucial function but doesn't emit any events. It is hard to keep track of the transactions if events aren't emitted.

Missing collateralBalanceBefore > 0 check

depositAndBorrow using collateralBalanceBefore = 0 may cause some problem

https://github.com/code-423n4/2022-08-mimo/blob/eb1a5016b69f72bc1e4fd3600a65e908bd228f13/contracts/actions/MIMOLeverage.sol#L119-L122

    uint256 collateralBalanceBefore = token.balanceOf(address(this));

    token.safeIncreaseAllowance(address(core), collateralBalanceBefore);
    core.depositAndBorrow(address(token), collateralBalanceBefore, swapAmount);

Add unchecked

https://github.com/code-423n4/2022-08-mimo/blob/eb1a5016b69f72bc1e4fd3600a65e908bd228f13/contracts/actions/MIMOLeverage.sol#L132-L135

unchecked {
    if (collateralBalanceAfter > flashloanRepayAmount) {
      token.safeIncreaseAllowance(address(core), collateralBalanceAfter - flashloanRepayAmount);
      core.deposit(address(token), collateralBalanceAfter - flashloanRepayAmount);
    }
}

collateralBalanceAfter > flashloanRepayAmount is already checked. No underflow occur on collateralBalanceAfter - flashloanRepayAmount