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Submission Details
Severity: medium
Invalid

Wrong minimumAmountOut calulation leads to failure of swap transactions

nuthan2x

Summary

The minimumAmountOut doesn't include the swapFee to calulate the amount out to be minimum.

Vulnerability Details

  • The minimumAmountOut doesn't include the swapFee to calulate the amount out to be minimum. But the amountIn param inside the struct data included the fee amountIn: _amount - swapFee.

function swap(bytes32 _inToken, bytes32 _outToken, uint256 _amount) external onlyOwner {
uint256 swapFee = _amount * ISmartVaultManagerV3(manager).swapFeeRate() / ISmartVaultManagerV3(manager).HUNDRED_PC();
address inToken = getSwapAddressFor(_inToken);
---> uint256 minimumAmountOut = calculateMinimumAmountOut(_inToken, _outToken, _amount);
ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
tokenIn: inToken,
tokenOut: getSwapAddressFor(_outToken),
fee: 3000,
recipient: address(this),
deadline: block.timestamp,
---> amountIn: _amount - swapFee,
amountOutMinimum: minimumAmountOut,
sqrtPriceLimitX96: 0
});
inToken == ISmartVaultManagerV3(manager).weth() ?
executeNativeSwapAndFee(params, swapFee) :
executeERC20SwapAndFee(params, swapFee);
}

Impact

Medium (failed swap transactions)

Tools Used

Manual review

Recommendations

  • Follow the below recommendation.

function swap(bytes32 _inToken, bytes32 _outToken, uint256 _amount) external onlyOwner {
uint256 swapFee = _amount * ISmartVaultManagerV3(manager).swapFeeRate() / ISmartVaultManagerV3(manager).HUNDRED_PC();
address inToken = getSwapAddressFor(_inToken);
- uint256 minimumAmountOut = calculateMinimumAmountOut(_inToken, _outToken, _amount);
+ uint256 minimumAmountOut = calculateMinimumAmountOut(_inToken, _outToken, _amount - swapFee);
ISwapRouter.ExactInputSingleParams memory params = ISwapRouter.ExactInputSingleParams({
tokenIn: inToken,
tokenOut: getSwapAddressFor(_outToken),
fee: 3000,
recipient: address(this),
deadline: block.timestamp,
amountIn: _amount - swapFee,
amountOutMinimum: minimumAmountOut,
sqrtPriceLimitX96: 0
});
inToken == ISmartVaultManagerV3(manager).weth() ?
executeNativeSwapAndFee(params, swapFee) :
executeERC20SwapAndFee(params, swapFee);
}
Updates

Lead Judging Commences

hrishibhat Lead Judge almost 2 years ago
Submission Judgement Published
Validated
Assigned finding tags:

swapfee-incorrect-calc

hrishibhat Lead Judge almost 2 years ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement
Assigned finding tags:

swapfee-incorrect-calc

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