Submission Details
Severity:
Incorrect fee calculation in TSwapPool::getInputAmountBasedOnOutput causes protocll to take too many tokens from users, resulting in lost fees
Summary
The protocol takes more fees than expected from users.
Vulnerability Details
The getInputAmountBasedOnOutput function is intended to calculate the amount of tokens a user should deposit given an amount of tokens of output tokens. However, the function currently miscalculates the resulting amount. When calculating the fee, it scales the amount by 10_000 instead of 1_000.
Impact
Protocol takes more fees than expected from users.
Tools Used
Recommendations
function getInputAmountBasedOnOutput(
uint256 outputAmount,
uint256 inputReserves,
uint256 outputReserves
)
public
pure
revertIfZero(outputAmount)
revertIfZero(outputReserves)
returns (uint256 inputAmount)
{
- return ((inputReserves * outputAmount) * 10_000) / ((outputReserves - outputAmount) * 997);
+ return ((inputReserves * outputAmount) * 1_000) / ((outputReserves - outputAmount) * 997);
}
Updates
Appeal created
inallhonesty over 1 year ago
Submission Judgement Published Assigned finding tags:
Incorrect fee calculation in TSwapPool::getInputAmountBasedOnOutput causes protocol to take too many tokens from users, resulting in lost fees
Rewards breakdown
nSLOC
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