Foundry DeFi Stablecoin CodeHawks Audit Contest
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DeFiFoundry
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Submission Details
Severity: medium
Valid

Fee-on-transfer token might cause accounting deficit when depositing and redeeming collateral.

RugpullDetector

Summary

For fee-on-transfer tokens, depositCollateral will not transfer amountCollateral actually.

But s_collateralDeposited[msg.sender][tokenCollateralAddress] is increased by amountCollateral.

So when redeeming, there will be no enough tokens available to redeem.

function depositCollateral(address tokenCollateralAddress, uint256 amountCollateral)
public
moreThanZero(amountCollateral)
isAllowedToken(tokenCollateralAddress)
nonReentrant
{
s_collateralDeposited[msg.sender][tokenCollateralAddress] += amountCollateral;
emit CollateralDeposited(msg.sender, tokenCollateralAddress, amountCollateral);
bool success = IERC20(tokenCollateralAddress).transferFrom(msg.sender, address(this), amountCollateral);
if (!success) {
revert DSCEngine__TransferFailed();
}
}

Impact

Late users might not be able to redeem collateral because of accounting deficit.

Tool used

Manual Review

Recommendation

s_collateralDeposited should be increase by actual amount changed.

function depositCollateral(address tokenCollateralAddress, uint256 amountCollateral)
public
moreThanZero(amountCollateral)
isAllowedToken(tokenCollateralAddress)
nonReentrant
{
- s_collateralDeposited[msg.sender][tokenCollateralAddress] += amountCollateral;
+ uint256 beforeBalance = IERC20(tokenCollateralAddress).balanceOf(address(this));
emit CollateralDeposited(msg.sender, tokenCollateralAddress, amountCollateral);
bool success = IERC20(tokenCollateralAddress).transferFrom(msg.sender, address(this), amountCollateral);
if (!success) {
revert DSCEngine__TransferFailed();
}
+ s_collateralDeposited[msg.sender][tokenCollateralAddress] += (IERC20(tokenCollateralAddress).balanceOf(address(this)) - beforeBalance);
}

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