Core Contracts
Regnum Aurum Acquisition Corp
HardhatReal World AssetsNFT
77,280 USDC
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Submission Details
Severity: medium
Valid

LendingPool does not have any reserve tokens to deposit into curve vault

SlayerSecurity

Summary

LendingPool does not have any reserve tokens to deposit into the curve vault.

Vulnerability Details

When deposit is called by a user, it deposits the funds directly into the RToken contract:

function deposit(uint256 amount) external nonReentrant whenNotPaused onlyValidAmount(amount) {
// Update the reserve state before the deposit
ReserveLibrary.updateReserveState(reserve, rateData);
​
// Perform the deposit through ReserveLibrary
uint256 mintedAmount = ReserveLibrary.deposit(reserve, rateData, amount, msg.sender);
​
// Rebalance liquidity after deposit
_rebalanceLiquidity();
​
emit Deposit(msg.sender, amount, mintedAmount);
}
// deposit function in ReserveLibrary
function deposit(ReserveData storage reserve,ReserveRateData storage rateData,uint256 amount,address depositor) internal returns (uint256 amountMinted) {
if (amount < 1) revert InvalidAmount();
​
// Update reserve interests
updateReserveInterests(reserve, rateData);
​
// Transfer asset from caller to the RToken contract
IERC20(reserve.reserveAssetAddress).safeTransferFrom(
msg.sender, // from
reserve.reserveRTokenAddress, // to
amount // amount
);

All the tokens from deposit are sent to the RToken, leaving no tokens behind in the LendingPool.
So, when _rebalanceLiquidity, is called when deposit in LendingPool is called:

function _rebalanceLiquidity() internal {
// if curve vault is not set, do nothing
if (address(curveVault) == address(0)) {
return;
}
​
uint256 totalDeposits = reserve.totalLiquidity; // Total liquidity in the system
uint256 desiredBuffer = totalDeposits.percentMul(liquidityBufferRatio);
uint256 currentBuffer = IERC20(reserve.reserveAssetAddress).balanceOf(reserve.reserveRTokenAddress);
​
if (currentBuffer > desiredBuffer) {
uint256 excess = currentBuffer - desiredBuffer;
// Deposit excess into the Curve vault
_depositIntoVault(excess);
} else if (currentBuffer < desiredBuffer) {
uint256 shortage = desiredBuffer - currentBuffer;
// Withdraw shortage from the Curve vault
_withdrawFromVault(shortage);
}
​
emit LiquidityRebalanced(currentBuffer, totalVaultDeposits);
}

The function calculates the excess amount and if there are more reserveAssetAddress tokens in the reserveRTokenAddress then it tries to deposit this excess amount in the curve vault. But, it does so without first transferring these reserveAssetAddress tokens from the RTokento the LendingPool. Hence, when it tries to deposit it into the curve vault, it reverts, as it won't have the excess tokens in its balance.

Impact

Deposits in LendingPool will revert.

Tools Used

Manual review

Recommendations

Before transferring the excess amount to the curve vault, transfer the tokens from the RToken to the LendingPool.

Updates

Lead Judging Commences

inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Validated
Assigned finding tags:

LendingPool::_depositIntoVault and _withdrawFromVault don't transfer tokens between RToken and LendingPool, breaking Curve vault interactions

inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Validated
Assigned finding tags:

LendingPool::_depositIntoVault and _withdrawFromVault don't transfer tokens between RToken and LendingPool, breaking Curve vault interactions

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