Liquidity Management
Gamma
DeFiFoundry
50,000 USDC
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Submission Details
Severity: low
Invalid

Unchecked Math in _absDiff()

maze

Summary

The _absDiff function in KeeperProxy can be optimized using unchecked math since the conditional logic already prevents underflows, leading to gas savings without compromising safety.

Technical Analysis

Current implementation:

function _absDiff(uint256 a, uint256 b) internal pure returns (uint256) {
if (a > b) return a - b;
else return b - a;
}

The function is safe by design because:

  1. Conditional check ensures larger number is always subtracted from

  2. Both inputs are uint256, preventing overflow scenarios

  3. Function is used only in price validation contexts

Impact

Severity: Gas Optimization (Low)

Effects:

  • Gas savings: ~40-100 per operation

  • No security implications

  • Cumulative savings with frequent price checks

Test Cases

contract KeeperProxyTest {
function testAbsDiffGasOptimization() public {
uint256 a = 1000;
uint256 b = 500;
// Test original
uint256 gasStart = gasleft();
uint256 result1 = keeper._absDiff(a, b);
uint256 gasUsed1 = gasStart - gasleft();
// Test optimized
gasStart = gasleft();
uint256 result2 = keeper._absDiffOptimized(a, b);
uint256 gasUsed2 = gasStart - gasleft();
assertEq(result1, result2);
assertLt(gasUsed2, gasUsed1);
}
}

Recommendation

function _absDiff(uint256 a, uint256 b) internal pure returns (uint256) {
unchecked {
return a > b ? a - b : b - a;
}
}

Gas Savings Breakdown

Operation Before After Savings
Single Call ~150 gas ~50 gas ~100 gas
Price Check (3 tokens) ~450 gas ~150 gas ~300 gas
Updates

Lead Judging Commences

n0kto Lead Judge 5 months ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Informational or Gas

Please read the CodeHawks documentation to know which submissions are valid. If you disagree, provide a coded PoC and explain the real likelihood and the detailed impact on the mainnet without any supposition (if, it could, etc) to prove your point.

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