Munchables - falconhoof's results

Lines of code

https://github.com/code-423n4/2024-05-munchables/blob/57dff486c3cd905f21b330c2157fe23da2a4807d/src/managers/LockManager.sol#L177-L207

Vulnerability details

Summary

Voting twice breaks intended voting logic

Vulnerability Details

It is never checked in approveUSDPrice() if the user has already voted against a proposal, allowing a user to first vote "disapprove" and then vote "approve".

Impact

A user can cast two votes; allowing a single user to manipulate the vote; breaking the voting logic.

Tools Used

Manual Review Foundry Testing

Recommendations

Add the missing check to approveUSDPrice() as below:

    function approveUSDPrice(uint256 _price)
        external
        onlyOneOfRoles(
            [
                Role.PriceFeed_1,
                Role.PriceFeed_2,
                Role.PriceFeed_3,
                Role.PriceFeed_4,
                Role.PriceFeed_5
            ]
        )
    {
        if (usdUpdateProposal.proposer == address(0)) 
            revert NoProposalError();
        if (usdUpdateProposal.proposer == msg.sender)
            revert ProposerCannotApproveError();
        if (usdUpdateProposal.approvals[msg.sender] == _usdProposalId)
            revert ProposalAlreadyApprovedError();
+       if (usdUpdateProposal.disapprovals[msg.sender] == _usdProposalId)
+           revert ProposalAlreadyDisapprovedError();
        if (usdUpdateProposal.proposedPrice != _price)
            revert ProposalPriceNotMatchedError();

        usdUpdateProposal.approvals[msg.sender] = _usdProposalId;
        usdUpdateProposal.approvalsCount++;

        if (usdUpdateProposal.approvalsCount >= APPROVE_THRESHOLD) {
            _execUSDPriceUpdate();
        }

        emit ApprovedUSDPrice(msg.sender);
    }

Assessed type

Invalid Validation