Beatland Festival

The `withdraw` function in the `FestivalPass` contract allows the contract owner to transfer all ETH

collected to a specified address. However, the implementation uses direct `transfer()`,

which is not gas-safe and can fail unexpectedly due to the fixed 2300 gas stipend limit imposed by transfer().

​

```javascript

function withdraw(address target) external onlyOwner {

payable(target).transfer(address(this).balance);

}

```

​

Direct ETH transfers using `.transfer()` are considered unsafe since EIP-1884,

which increased the gas cost of certain opcodes and may cause transfer() to fail on some smart contract wallets like multisigs.

​

Risk: DoS (Denial of Service to withdraw funds), lost funds access

​

1. Contract owner could lose access to funds if transfer() fails due to recipient gas usage.

​

2. Funds could be locked forever if recipient is a contract not compatible with transfer().

​

Deploy `FestivalPass` and call `withdraw()` using a recipient address that has a fallback function consuming more than 2300 gas:

​

Add follwing in `FestivalPass.t.sol`

```javascript

contract FallbackRevert {

fallback() external payable {

require(gasleft() > 10000, "Consumes too much gas");

}

}

```

and test following test, it will be reverted due to more gas error.

​

```javascript

function testWithdrawRevertsOnGasHeavyFallback() public {

// Deploy fallback contract

FallbackRevert br = new FallbackRevert();

​

// Fund festival contract by buying passes

vm.prank(user1);

festivalPass.buyPass{value: GENERAL_PRICE}(1);

​

// Attempt withdraw

vm.prank(owner);

vm.expectRevert(); // .transfer should revert

festivalPass.withdraw(address(br));

}

```

​

- Call withdraw(address(receiver)) from owner.

​

- Transaction will revert due to .transfer() failing to deliver ETH.

​

Use a low-level call with manual success check, which avoids the 2300 gas limit problem:

​

```diff

function withdraw(address target) external onlyOwner {

}

```

​

Why this is better:

​

~ call forwards all available gas (unless specified otherwise).

​

~ More compatible with smart contract wallets.

​

~ Can safely handle larger logic in the recipient contract.

​

​