First Flight #18: T-Swap
First Flight #18
Beginner FriendlyDeFiFoundry
100 EXP
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Submission Details
Severity: medium
Valid

Missing Deadline

10ap17

Summary

The deposit function in the TSwap contract contains a vulnerability due to an unused deadline parameter. This flaw allows transactions to complete even after the specified deadline, which can lead to unexpected behavior and potential exploitation.

Vulnerability Details

The deposit function in the TSwap contract has a significant issue where the deadline parameter, although defined, is not utilized within the function. This oversight means that the function does not enforce any time constraints, allowing deposits to be processed regardless of the specified deadline. Users expect that transactions will fail if they do not meet the specified deadline, but since this parameter is not checked or used in any way, the function will execute successfully even if the deadline has passed. This flaw can lead to unexpected behavior and potential exploitation, as transactions can occur outside the intended time frame. This vulnerability needs to be addressed promptly to ensure the contract operates as intended and maintains its integrity and reliability.

function deposit(
uint256 wethToDeposit,
uint256 minimumLiquidityTokensToMint,
uint256 maximumPoolTokensToDeposit,
uint64 deadline
)
external
revertIfZero(wethToDeposit)
returns (uint256 liquidityTokensToMint)
{
if (wethToDeposit < MINIMUM_WETH_LIQUIDITY) {
revert TSwapPool__WethDepositAmountTooLow(
MINIMUM_WETH_LIQUIDITY,
wethToDeposit
);
}
if (totalLiquidityTokenSupply() > 0) {
uint256 wethReserves = i_wethToken.balanceOf(address(this));
uint256 poolTokenReserves = i_poolToken.balanceOf(address(this));
uint256 poolTokensToDeposit = getPoolTokensToDepositBasedOnWeth(
wethToDeposit
);
if (maximumPoolTokensToDeposit < poolTokensToDeposit) {
revert TSwapPool__MaxPoolTokenDepositTooHigh(
maximumPoolTokensToDeposit,
poolTokensToDeposit
);
}
​
// We do the same thing for liquidity tokens. Similar math.
liquidityTokensToMint =
(wethToDeposit * totalLiquidityTokenSupply()) /
wethReserves;
if (liquidityTokensToMint < minimumLiquidityTokensToMint) {
revert TSwapPool__MinLiquidityTokensToMintTooLow(
minimumLiquidityTokensToMint,
liquidityTokensToMint
);
}
_addLiquidityMintAndTransfer(
wethToDeposit,
poolTokensToDeposit,
liquidityTokensToMint
);
} else {
// This will be the "initial" funding of the protocol. We are starting from blank here!
// We just have them send the tokens in, and we mint liquidity tokens based on the weth
_addLiquidityMintAndTransfer(
wethToDeposit,
maximumPoolTokensToDeposit,
wethToDeposit
);
liquidityTokensToMint = wethToDeposit;
}
}

Impact

The unused deadline parameter can have several impacts:

  1. Operational Risk: Users and automated systems that depend on the deadline for operational correctness may face unexpected behavior, causing potential financial and logistical issues.

  2. Trustworthiness: The integrity and reliability of the TSwap contract may be called into question, leading to a loss of trust among users and stakeholders.

  3. Regulatory Compliance: For financial contracts, adhering to specific time constraints might be a regulatory requirement. Failing to enforce deadlines can lead to non-compliance issues.

Tools Used

  1. Manual Code Review

Recommendations

Implement the revertIfDeadlinePassed modifier to enforce the deadline check within the deposit function and other relevant functions in the contract. This approach ensures a consistent and reusable method for handling `deadlines, reducing the risk of similar issues in the future.

function deposit(
uint256 wethToDeposit,
uint256 minimumLiquidityTokensToMint,
uint256 maximumPoolTokensToDeposit,
uint64 deadline
)
external
revertIfZero(wethToDeposit)
+ revertIfDeadlinePassed(deadline)
returns (uint256 liquidityTokensToMint)
{
if (wethToDeposit < MINIMUM_WETH_LIQUIDITY) {
revert TSwapPool__WethDepositAmountTooLow(
MINIMUM_WETH_LIQUIDITY,
wethToDeposit
);
}
if (totalLiquidityTokenSupply() > 0) {
uint256 wethReserves = i_wethToken.balanceOf(address(this));
uint256 poolTokenReserves = i_poolToken.balanceOf(address(this));
uint256 poolTokensToDeposit = getPoolTokensToDepositBasedOnWeth(
wethToDeposit
);
if (maximumPoolTokensToDeposit < poolTokensToDeposit) {
revert TSwapPool__MaxPoolTokenDepositTooHigh(
maximumPoolTokensToDeposit,
poolTokensToDeposit
);
}
​
// We do the same thing for liquidity tokens. Similar math.
liquidityTokensToMint =
(wethToDeposit * totalLiquidityTokenSupply()) /
wethReserves;
if (liquidityTokensToMint < minimumLiquidityTokensToMint) {
revert TSwapPool__MinLiquidityTokensToMintTooLow(
minimumLiquidityTokensToMint,
liquidityTokensToMint
);
}
_addLiquidityMintAndTransfer(
wethToDeposit,
poolTokensToDeposit,
liquidityTokensToMint
);
} else {
// This will be the "initial" funding of the protocol. We are starting from blank here!
// We just have them send the tokens in, and we mint liquidity tokens based on the weth
_addLiquidityMintAndTransfer(
wethToDeposit,
maximumPoolTokensToDeposit,
wethToDeposit
);
liquidityTokensToMint = wethToDeposit;
}
}
Updates

Appeal created

inallhonesty Lead Judge 12 months ago
Submission Judgement Published
Validated
Assigned finding tags:

`deposit` is missing deadline check causing transactions to complete even after the deadline

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