pd.currentPrice in calcReserveAtRatioSwap() is not updated correctly.

[howlbot-integration]

Lines of code

https://github.com/code-423n4/2024-07-basin/blob/7d5aacbb144d0ba0bc358dfde6e0cc913d25310e/src/functions/Stable2.sol#L226

Vulnerability details

Impact

currentPrice is converged towards targetPrice as reserve of token0 or token1 changes.

for (uint256 k; k < 255; k++) {
            scaledReserves[j] = updateReserve(pd, scaledReserves[j]);

            // calculate scaledReserve[i]:
            scaledReserves[i] = calcReserve(scaledReserves, i, lpTokenSupply, abi.encode(18, 18));
            // calc currentPrice:
            pd.currentPrice = _calcRate(scaledReserves, i, j, lpTokenSupply);
            ....
}

lpTokenSupply is calculated from scaledReserves which is updated inside for loop. But lpTokenSupply in here is calculated only once before for loop and keeps unchanged.

Tools Used

Manual audit

Recommended Mitigation Steps

            // calc currentPrice:
-           pd.currentPrice = _calcRate(scaledReserves, i, j, lpTokenSupply);
+           pd.currentPrice = calcRate(scaledReserves, i, j, abi.encode(18, 18));

Assessed type

Other

[c4-judge]

alex-ppg marked the issue as unsatisfactory:
Invalid