sendParam.minAmountLD slippage setting is too strict

mediumCode4rena

Lines of code

https://github.com/Tapioca-DAO/tapioca-periph/blob/032396f701be935b04a7e5cf3cb40a0136259dbc/contracts/Magnetar/modules/MagnetarAssetModule.sol#L132

Vulnerability details

Impact

sendParam.minAmountLD slippage setting is too strict

Proof of Concept

Across the codebase,

 if (data.collateralAmount > 0) {
            address collateralWithdrawReceiver = data.withdrawCollateralParams.withdraw ? address(this) : data.user;
            uint256 collateralShare = _yieldBox.toShare(_market.collateralId(), data.collateralAmount, false);

            (Module[] memory modules, bytes[] memory calls) = IMarketHelper(data.marketHelper).removeCollateral(
                data.user, collateralWithdrawReceiver, collateralShare
            );
            _market.execute(modules, calls, true);

            //withdraw
            if (data.withdrawCollateralParams.withdraw) {
                uint256 collateralId = _market.collateralId();
                if (data.withdrawCollateralParams.assetId != collateralId) revert Magnetar_WithdrawParamsMismatch();

                // @dev re-calculate amount
                if (collateralShare > 0) {
                    uint256 computedCollateral = _yieldBox.toAmount(collateralId, collateralShare, false);
                    if (computedCollateral == 0) revert Magnetar_WithdrawParamsMismatch();

                    data.withdrawCollateralParams.lzSendParams.sendParam.amountLD = computedCollateral;
                    data.withdrawCollateralParams.lzSendParams.sendParam.minAmountLD = computedCollateral;
                    _withdrawToChain(data.withdrawCollateralParams);
                }
            }
        }

the minAmonutLD and amountLD is set to equal value

However, minAmonutLD served as a slippage control on layerzero v2 side,

and 0% slippage is not always possible, then the cross-chain transaction will always reverted in too strict slippage contract and block asset transfer

https://github.com/LayerZero-Labs/LayerZero-v2/blob/142846c3d6d51e3c2a0852c41b4c2b63fcda5a0a/oapp/contracts/oft/OFTCore.sol#L345

 function _debitView(
        uint256 _amountLD,
        uint256 _minAmountLD,
        uint32 /*_dstEid*/
    ) internal view virtual returns (uint256 amountSentLD, uint256 amountReceivedLD) {
        // @dev Remove the dust so nothing is lost on the conversion between chains with different decimals for the token.
        amountSentLD = _removeDust(_amountLD);
        // @dev The amount to send is the same as amount received in the default implementation.
        amountReceivedLD = amountSentLD;

        // @dev Check for slippage.
        if (amountReceivedLD < _minAmountLD) {
            revert SlippageExceeded(amountReceivedLD, _minAmountLD);
        }
    }

Tools Used

Manual Review

Recommended Mitigation Steps

Let user input a percentage and compute minAmountLD based on a percentage of slippage user is willing to take risk of

Assessed type

Token-Transfer