Submission Details
Severity:
Long functions should be refactored into multiple, smaller, functions
Summary
Long functions should be refactored into multiple, smaller, functions
Vulnerability Details
File: src/Lender.sol
232: function borrow(Borrow[] calldata borrows) public {
for (uint256 i = 0; i < borrows.length; i++) {
bytes32 poolId = borrows[i].poolId;
uint256 debt = borrows[i].debt;
uint256 collateral = borrows[i].collateral;
// get the pool info
Pool memory pool = pools[poolId];
// make sure the pool exists
if (pool.lender == address(0)) revert PoolConfig();
// validate the loan
if (debt < pool.minLoanSize) revert LoanTooSmall();
if (debt > pool.poolBalance) revert LoanTooLarge();
if (collateral == 0) revert ZeroCollateral();
// make sure the user isn't borrowing too much
uint256 loanRatio = (debt * 10 ** 18) / collateral;
if (loanRatio > pool.maxLoanRatio) revert RatioTooHigh();
// create the loan
Loan memory loan = Loan({
lender: pool.lender,
borrower: msg.sender,
loanToken: pool.loanToken,
collateralToken: pool.collateralToken,
debt: debt,
collateral: collateral,
interestRate: pool.interestRate,
startTimestamp: block.timestamp,
auctionStartTimestamp: type(uint256).max,
auctionLength: pool.auctionLength
});
// update the pool balance
_updatePoolBalance(poolId, pools[poolId].poolBalance - debt);
pools[poolId].outstandingLoans += debt;
// calculate the fees
uint256 fees = (debt * borrowerFee) / 10000;
// transfer fees
IERC20(loan.loanToken).transfer(feeReceiver, fees);
// transfer the loan tokens from the pool to the borrower
IERC20(loan.loanToken).transfer(msg.sender, debt - fees);
// transfer the collateral tokens from the borrower to the contract
IERC20(loan.collateralToken).transferFrom(
msg.sender,
address(this),
collateral
);
loans.push(loan);
emit Borrowed(
msg.sender,
pool.lender,
loans.length - 1,
debt,
collateral,
pool.interestRate,
block.timestamp
);
}
}
292: function repay(uint256[] calldata loanIds) public {
for (uint256 i = 0; i < loanIds.length; i++) {
uint256 loanId = loanIds[i];
// get the loan info
Loan memory loan = loans[loanId];
// calculate the interest
(
uint256 lenderInterest,
uint256 protocolInterest
) = _calculateInterest(loan);
bytes32 poolId = getPoolId(
loan.lender,
loan.loanToken,
loan.collateralToken
);
// update the pool balance
_updatePoolBalance(
poolId,
pools[poolId].poolBalance + loan.debt + lenderInterest
);
pools[poolId].outstandingLoans -= loan.debt;
// transfer the loan tokens from the borrower to the pool
IERC20(loan.loanToken).transferFrom(
msg.sender,
address(this),
loan.debt + lenderInterest
);
// transfer the protocol fee to the fee receiver
IERC20(loan.loanToken).transferFrom(
msg.sender,
feeReceiver,
protocolInterest
);
// transfer the collateral tokens from the contract to the borrower
IERC20(loan.collateralToken).transfer(
loan.borrower,
loan.collateral
);
emit Repaid(
msg.sender,
loan.lender,
loanId,
loan.debt,
loan.collateral,
loan.interestRate,
loan.startTimestamp
);
// delete the loan
delete loans[loanId];
}
}
355: function giveLoan(
uint256[] calldata loanIds,
bytes32[] calldata poolIds
) external {
for (uint256 i = 0; i < loanIds.length; i++) {
uint256 loanId = loanIds[i];
bytes32 poolId = poolIds[i];
// get the loan info
Loan memory loan = loans[loanId];
// validate the loan
if (msg.sender != loan.lender) revert Unauthorized();
// get the pool info
Pool memory pool = pools[poolId];
// validate the new loan
if (pool.loanToken != loan.loanToken) revert TokenMismatch();
if (pool.collateralToken != loan.collateralToken)
revert TokenMismatch();
// new interest rate cannot be higher than old interest rate
if (pool.interestRate > loan.interestRate) revert RateTooHigh();
// auction length cannot be shorter than old auction length
if (pool.auctionLength < loan.auctionLength) revert AuctionTooShort();
// calculate the interest
(
uint256 lenderInterest,
uint256 protocolInterest
) = _calculateInterest(loan);
uint256 totalDebt = loan.debt + lenderInterest + protocolInterest;
if (pool.poolBalance < totalDebt) revert PoolTooSmall();
if (totalDebt < pool.minLoanSize) revert LoanTooSmall();
uint256 loanRatio = (totalDebt * 10 ** 18) / loan.collateral;
if (loanRatio > pool.maxLoanRatio) revert RatioTooHigh();
// update the pool balance of the new lender
_updatePoolBalance(poolId, pool.poolBalance - totalDebt);
pools[poolId].outstandingLoans += totalDebt;
// update the pool balance of the old lender
bytes32 oldPoolId = getPoolId(
loan.lender,
loan.loanToken,
loan.collateralToken
);
_updatePoolBalance(
oldPoolId,
pools[oldPoolId].poolBalance + loan.debt + lenderInterest
);
pools[oldPoolId].outstandingLoans -= loan.debt;
// transfer the protocol fee to the governance
IERC20(loan.loanToken).transfer(feeReceiver, protocolInterest);
emit Repaid(
loan.borrower,
loan.lender,
loanId,
loan.debt + lenderInterest + protocolInterest,
loan.collateral,
loan.interestRate,
loan.startTimestamp
);
// update the loan with the new info
loans[loanId].lender = pool.lender;
loans[loanId].interestRate = pool.interestRate;
loans[loanId].startTimestamp = block.timestamp;
loans[loanId].auctionStartTimestamp = type(uint256).max;
loans[loanId].debt = totalDebt;
emit Borrowed(
loan.borrower,
pool.lender,
loanId,
loans[loanId].debt,
loans[loanId].collateral,
pool.interestRate,
block.timestamp
);
}
}
465: function buyLoan(uint256 loanId, bytes32 poolId) public {
// get the loan info
Loan memory loan = loans[loanId];
// validate the loan
if (loan.auctionStartTimestamp == type(uint256).max)
revert AuctionNotStarted();
if (block.timestamp > loan.auctionStartTimestamp + loan.auctionLength)
revert AuctionEnded();
// calculate the current interest rate
uint256 timeElapsed = block.timestamp - loan.auctionStartTimestamp;
uint256 currentAuctionRate = (MAX_INTEREST_RATE * timeElapsed) /
loan.auctionLength;
// validate the rate
if (pools[poolId].interestRate > currentAuctionRate) revert RateTooHigh();
// calculate the interest
(uint256 lenderInterest, uint256 protocolInterest) = _calculateInterest(
loan
);
// reject if the pool is not big enough
uint256 totalDebt = loan.debt + lenderInterest + protocolInterest;
if (pools[poolId].poolBalance < totalDebt) revert PoolTooSmall();
// if they do have a big enough pool then transfer from their pool
_updatePoolBalance(poolId, pools[poolId].poolBalance - totalDebt);
pools[poolId].outstandingLoans += totalDebt;
// now update the pool balance of the old lender
bytes32 oldPoolId = getPoolId(
loan.lender,
loan.loanToken,
loan.collateralToken
);
_updatePoolBalance(
oldPoolId,
pools[oldPoolId].poolBalance + loan.debt + lenderInterest
);
pools[oldPoolId].outstandingLoans -= loan.debt;
// transfer the protocol fee to the governance
IERC20(loan.loanToken).transfer(feeReceiver, protocolInterest);
emit Repaid(
loan.borrower,
loan.lender,
loanId,
loan.debt + lenderInterest + protocolInterest,
loan.collateral,
loan.interestRate,
loan.startTimestamp
);
// update the loan with the new info
loans[loanId].lender = msg.sender;
loans[loanId].interestRate = pools[poolId].interestRate;
loans[loanId].startTimestamp = block.timestamp;
loans[loanId].auctionStartTimestamp = type(uint256).max;
loans[loanId].debt = totalDebt;
emit Borrowed(
loan.borrower,
msg.sender,
loanId,
loans[loanId].debt,
loans[loanId].collateral,
pools[poolId].interestRate,
block.timestamp
);
emit LoanBought(loanId);
}
591: function refinance(Refinance[] calldata refinances) public {
for (uint256 i = 0; i < refinances.length; i++) {
uint256 loanId = refinances[i].loanId;
bytes32 poolId = refinances[i].poolId;
bytes32 oldPoolId = keccak256(
abi.encode(
loans[loanId].lender,
loans[loanId].loanToken,
loans[loanId].collateralToken
)
);
uint256 debt = refinances[i].debt;
uint256 collateral = refinances[i].collateral;
// get the loan info
Loan memory loan = loans[loanId];
// validate the loan
if (msg.sender != loan.borrower) revert Unauthorized();
// get the pool info
Pool memory pool = pools[poolId];
// validate the new loan
if (pool.loanToken != loan.loanToken) revert TokenMismatch();
if (pool.collateralToken != loan.collateralToken)
revert TokenMismatch();
if (pool.poolBalance < debt) revert LoanTooLarge();
if (debt < pool.minLoanSize) revert LoanTooSmall();
uint256 loanRatio = (debt * 10 ** 18) / collateral;
if (loanRatio > pool.maxLoanRatio) revert RatioTooHigh();
// calculate the interest
(
uint256 lenderInterest,
uint256 protocolInterest
) = _calculateInterest(loan);
uint256 debtToPay = loan.debt + lenderInterest + protocolInterest;
// update the old lenders pool
_updatePoolBalance(
oldPoolId,
pools[oldPoolId].poolBalance + loan.debt + lenderInterest
);
pools[oldPoolId].outstandingLoans -= loan.debt;
// now lets deduct our tokens from the new pool
_updatePoolBalance(poolId, pools[poolId].poolBalance - debt);
pools[poolId].outstandingLoans += debt;
if (debtToPay > debt) {
// we owe more in debt so we need the borrower to give us more loan tokens
// transfer the loan tokens from the borrower to the contract
IERC20(loan.loanToken).transferFrom(
msg.sender,
address(this),
debtToPay - debt
);
} else if (debtToPay < debt) {
// we have excess loan tokens so we give some back to the borrower
// first we take our borrower fee
uint256 fee = (borrowerFee * (debt - debtToPay)) / 10000;
IERC20(loan.loanToken).transfer(feeReceiver, fee);
// transfer the loan tokens from the contract to the borrower
IERC20(loan.loanToken).transfer(msg.sender, debt - debtToPay - fee);
}
// transfer the protocol fee to governance
IERC20(loan.loanToken).transfer(feeReceiver, protocolInterest);
// update loan debt
loans[loanId].debt = debt;
// update loan collateral
if (collateral > loan.collateral) {
// transfer the collateral tokens from the borrower to the contract
IERC20(loan.collateralToken).transferFrom(
msg.sender,
address(this),
collateral - loan.collateral
);
} else if (collateral < loan.collateral) {
// transfer the collateral tokens from the contract to the borrower
IERC20(loan.collateralToken).transfer(
msg.sender,
loan.collateral - collateral
);
}
emit Repaid(
msg.sender,
loan.lender,
loanId,
debt,
collateral,
loan.interestRate,
loan.startTimestamp
);
loans[loanId].collateral = collateral;
// update loan interest rate
loans[loanId].interestRate = pool.interestRate;
// update loan start timestamp
loans[loanId].startTimestamp = block.timestamp;
// update loan auction start timestamp
loans[loanId].auctionStartTimestamp = type(uint256).max;
// update loan auction length
loans[loanId].auctionLength = pool.auctionLength;
// update loan lender
loans[loanId].lender = pool.lender;
// update pool balance
pools[poolId].poolBalance -= debt;
emit Borrowed(
msg.sender,
pool.lender,
loanId,
debt,
collateral,
pool.interestRate,
block.timestamp
);
emit Refinanced(loanId);
}
}
Link to code - https://github.com/Cyfrin/2023-07-beedle/tree/main/src/Lender.sol
Tools Used
Manual Code Review by SolSaver
Recommendations
Try to keep the functions smaller by breaking it down into smaller functions.
Prize pool breakdown
Total prize
20,000 USDC
nSLOC
70628 USDC / LOC
18,000 USDC
2,000 USDC
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