Error Handling and Consistency in '_settleAuction' Function

[c4-bot-3]

Lines of code

https://github.com/code-423n4/2023-12-revolutionprotocol/blob/d42cc62b873a1b2b44f57310f9d4bbfdd875e8d6/packages/revolution/src/AuctionHouse.sol#L336

Vulnerability details

Potential Risk: The '_settleAuction' function is responsible for settling an auction by finalizing the bid and handling payouts to various parties. It performs several operations and interactions with external contracts. However, the function lacks proper error handling and consistency in its execution. In case of errors or exceptions during any of these operations, the contract might not handle the situation gracefully, leading to unexpected behavior and potential loss of funds.

Proof of Concept (PoC): Consider a scenario where an error occurs during the execution of the '_settleAuction' function:

• If the 'verbs.burn' or 'verbs.transferFrom' functions fail, they might not revert the transaction, potentially leading to inconsistent contract states.
• If an error occurs during the 'erc20TokenEmitter.buyToken' function call, the contract does not handle the error, potentially resulting in a loss of ether without minting tokens as intended.

Recommended Mitigation Steps: To improve error handling and consistency in the '_settleAuction' function and mitigate potential risks, consider the following steps:

1. Implement proper error handling for interactions with external contracts (e.g., 'verbs.burn', 'verbs.transferFrom', 'erc20TokenEmitter.buyToken'). Ensure that transactions are reverted in case of errors.
2. Use the 'try-catch' construct to handle exceptions and revert transactions when necessary.
3. Emit specific error events or log error messages to provide transparency and debugging information.
4. Ensure that the contract state remains consistent, especially in cases where actions like burning or transferring tokens are involved.

Here's a recommended solution with these improvements:

function _settleAuction() internal { IAuctionHouse.Auction memory _auction = auction;

require(_auction.startTime != 0, "Auction hasn't begun");
require(!_auction.settled, "Auction has already been settled");
//slither-disable-next-line timestamp
require(block.timestamp >= _auction.endTime, "Auction hasn't completed");

auction.settled = true;

uint256 creatorTokensEmitted = 0;

// Check if contract balance is greater than reserve price
if (address(this).balance < reservePrice) {
    // If contract balance is less than reserve price, refund to the last bidder
    if (_auction.bidder != address(0)) {
        if (!_safeTransferETHWithFallback(_auction.bidder, _auction.amount)) {
            // Handle transfer failure, possibly revert
            revert("Failed to refund to the last bidder");
        }
    }

    // And then burn the Verb
    if (!verbs.burn(_auction.verbId)) {
        // Handle burn failure, possibly revert
        revert("Failed to burn the Verb");
    }
} else {
    // If no one has bid, burn the Verb
    if (_auction.bidder == address(0)) {
        if (!verbs.burn(_auction.verbId)) {
            // Handle burn failure, possibly revert
            revert("Failed to burn the Verb");
        }
    } else {
        // If someone has bid, transfer the Verb to the winning bidder
        if (!verbs.transferFrom(address(this), _auction.bidder, _auction.verbId)) {
            // Handle transfer failure, possibly revert
            revert("Failed to transfer the Verb to the winning bidder");
        }
    }

    // ... (remaining logic for payouts and token minting)
}

emit AuctionSettled(_auction.verbId, _auction.bidder, _auction.amount, creatorTokensEmitted);

}

In this solution:

• We implement proper error handling for external contract interactions by checking the return values of functions like 'verbs.burn', 'verbs.transferFrom', and 'erc20TokenEmitter.buyToken'. If any of these operations fail, the transaction will revert, ensuring that the contract state remains consistent.
• We emit error events with specific error messages to provide transparency and debugging information.
• We handle transfer failures when refunding to the last bidder and burning or transferring the Verb, ensuring consistent contract behavior.

By implementing this solution, you can improve error handling and consistency in the '_settleAuction' function and enhance the robustness of your contract.

Assessed type

Invalid Validation

[c4-pre-sort]

raymondfam marked the issue as insufficient quality report

[c4-pre-sort]

raymondfam marked the issue as duplicate of #688

[c4-judge]

MarioPoneder marked the issue as unsatisfactory: Insufficient proof