Submission Details
Severity:
Precision loss
Summary
Precision loss
Vulnerability Details
To avoid loss in precision, perform multiplication before division.
Impact
https://github.com/Cyfrin/2023-07-foundry-defi-stablecoin/blob/d1c5501aa79320ca0aeaa73f47f0dbc88c7b77e2/src/DSCEngine.sol#L330-L331
function _calculateHealthFactor(uint256 totalDscMinted, uint256 collateralValueInUsd)
internal
pure
returns (uint256)
{
if (totalDscMinted == 0) return type(uint256).max;
uint256 collateralAdjustedForThreshold = (collateralValueInUsd * LIQUIDATION_THRESHOLD) / 100;
return (collateralAdjustedForThreshold * 1e18) / totalDscMinted;
}
Division before multiplication can lead to truncation and give an incorrect output.
Tools Used
Manual review
Recommendations
function _calculateHealthFactor(uint256 totalDscMinted, uint256 collateralValueInUsd)
internal
pure
returns (uint256)
{
if (totalDscMinted == 0) return type(uint256).max;
// Multiply first to prevent truncation, then divide
return (collateralValueInUsd * LIQUIDATION_THRESHOLD * 1e18) / (totalDscMinted * 100);
}
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
23664 USDC / LOC
14,000 USDC
1,000 USDC
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.