First Flight #21: KittyFi

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Submission Details

Severity: low

Invalid

G-01: `whiskdrawMeowllateral()` transfer before checking, resulting in gas wastage when revert

0xlasadie

Summary

The whiskdrawMeowllateral() function performs the transfer of tokens first before checking if there is enough collateral. In the event if there is insufficient colleteral, the transaction will revert and causing the gas for transferring the tokens to be wasted.

Vulnerability Details

The function transfer tokens first before checking if there is enough collateral.

function whiskdrawMeowllateral(address _token, uint256 _ameownt) external tokenExists(_token) {

IKittyVault(tokenToVault[_token]).executeWhiskdrawal(msg.sender, _ameownt);

require(_hasEnoughMeowllateral(msg.sender), KittyPool__NotEnoughMeowllateralPurrrr());

}

Impact

This PoC will simulate a user depositing collateral and minting, thereafter to withdraw when there is not enough collateral and resulting in revert. This results in wasting 3297 gas.

function test_WhiskdrawMeowllateralRevertWasteGas() public {

address doggo = address(888);

uint256 initialDeposit = 5 ether;

// Setup: Fund doggo and deposit collateral

deal(weth, doggo, 10 ether);

vm.startPrank(doggo);

IERC20(weth).approve(address(wethVault), initialDeposit);

kittyPool.depawsitMeowllateral(weth, initialDeposit);

kittyPool.meowintKittyCoin(20e18);

vm.stopPrank();

// Attempt to withdraw and expecting a revert

vm.startPrank(doggo);

uint256 withdrawAmount = 5 ether;

try kittyPool.whiskdrawMeowllateral(weth, withdrawAmount) {

console.log("Withdrawal succeeded unexpectedly");

} catch {

console.log("Withdrawal reverted due to insufficient collateral");

}

vm.stopPrank();

}

Result

Ran 1 test for test/KittyFiTest.t.sol:KittyFiTest

[PASS] test_WhiskdrawMeowllateralRevertWasteGas() (gas: 454421)

Logs:

Withdrawal reverted due to insufficient collateral

Traces:

[454421] KittyFiTest::test_WhiskdrawMeowllateralRevertWasteGas()

...

[0] VM::startPrank(0x0000000000000000000000000000000000000378)

│ └─ ← [Return]

├─ [36516] KittyPool::whiskdrawMeowllateral(0xC558DBdd856501FCd9aaF1E62eae57A9F0629a3c, 5000000000000000000 [5e18])

│ ├─ [15619] KittyVault::executeWhiskdrawal(0x0000000000000000000000000000000000000378, 5000000000000000000 [5e18])

│ │ ├─ [4859] 0x6Ae43d3271ff6888e7Fc43Fd7321a503ff738951::getUserAccountData(KittyVault: [0x4a89a6cFA7bB08AeAee2B1A63cDA0CdD5720Bc91]) [staticcall]

│ │ │ ├─ [4283] 0x0562453c3DAFBB5e625483af58f4E6D668c44e19::getUserAccountData(KittyVault: [0x4a89a6cFA7bB08AeAee2B1A63cDA0CdD5720Bc91]) [delegatecall]

│ │ │ │ ├─ [402] 0x012bAC54348C0E635dCAc9D5FB99f06F24136C9A::getPriceOracle() [staticcall]

│ │ │ │ │ └─ ← [Return] 0x0000000000000000000000002da88497588bf89281816106c7259e31af45a663

│ │ │ │ ├─ [1521] 0x1ce1bA9946C30b4C505631AD9E3E0342877FdE02::26ec273f(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) [delegatecall]

│ │ │ │ │ └─ ← [Return] 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff

│ │ │ │ └─ ← [Return] 0, 0, 0, 0, 0, 115792089237316195423570985008687907853269984665640564039457584007913129639935 [1.157e77]

│ │ │ └─ ← [Return] 0, 0, 0, 0, 0, 115792089237316195423570985008687907853269984665640564039457584007913129639935 [1.157e77]

│ │ ├─ [3543] 0x694AA1769357215DE4FAC081bf1f309aDC325306::latestRoundData() [staticcall]

│ │ │ ├─ [1612] 0x719E22E3D4b690E5d96cCb40619180B5427F14AE::latestRoundData() [staticcall]

│ │ │ │ └─ ← [Return] 14925 [1.492e4], 251894720686 [2.518e11], 1722957240 [1.722e9], 1722957240 [1.722e9], 14925 [1.492e4]

│ │ │ └─ ← [Return] 18446744073709566541 [1.844e19], 251894720686 [2.518e11], 1722957240 [1.722e9], 1722957240 [1.722e9], 18446744073709566541 [1.844e19]

+ │ │ ├─ [3297] 0xC558DBdd856501FCd9aaF1E62eae57A9F0629a3c::transfer(0x0000000000000000000000000000000000000378, 5000000000000000000 [5e18])

│ │ │ ├─ emit Transfer(from: KittyVault: [0x4a89a6cFA7bB08AeAee2B1A63cDA0CdD5720Bc91], to: 0x0000000000000000000000000000000000000378, value: 5000000000000000000 [5e18])

│ │ │ └─ ← [Return] true

│ │ └─ ← [Return]

│ ├─ [18901] KittyVault::getUserVaultMeowllateralInEuros(0x0000000000000000000000000000000000000378) [staticcall]

│ │ ├─ [3543] 0x694AA1769357215DE4FAC081bf1f309aDC325306::latestRoundData() [staticcall]

│ │ │ ├─ [1612] 0x719E22E3D4b690E5d96cCb40619180B5427F14AE::latestRoundData() [staticcall]

│ │ │ │ └─ ← [Return] 14925 [1.492e4], 251894720686 [2.518e11], 1722957240 [1.722e9], 1722957240 [1.722e9], 14925 [1.492e4]

│ │ │ └─ ← [Return] 18446744073709566541 [1.844e19], 251894720686 [2.518e11], 1722957240 [1.722e9], 1722957240 [1.722e9], 18446744073709566541 [1.844e19]

│ │ ├─ [3543] 0x1a81afB8146aeFfCFc5E50e8479e826E7D55b910::latestRoundData() [staticcall]

│ │ │ ├─ [1612] 0xD404D68e5616e9C7045be2Dc1C5865EE328B6638::latestRoundData() [staticcall]

│ │ │ │ └─ ← [Return] 1666, 109265000 [1.092e8], 1722931836 [1.722e9], 1722931836 [1.722e9], 1666

│ │ │ └─ ← [Return] 18446744073709553282 [1.844e19], 109265000 [1.092e8], 1722931836 [1.722e9], 1722931836 [1.722e9], 18446744073709553282 [1.844e19]