Submission Details
Severity:
Incorrect fee calculation in TSwapPool::getInputAmountBasedOnOutput causes protocol to take too many tokens from users, resulting in lost fees
Description: 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.
Recommended Mitigation:
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); // remove this line
+ return ((inputReserves * outputAmount) * 1_000) / ((outputReserves - outputAmount) * 997); // add this line
}
Updates
Appeal created
inallhonesty about 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
276This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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.