Lines of code

Vulnerability details

Impact

The VetoProposal contract allows to veto proposals with the voteToVeto function.

The proposal can only be vetoed when it is in the Voting state, otherwise the voteToVeto function reverts.

The issue is that the Voting state is not the only state in which it should be possible to veto the proposal. It should also be possible to veto the proposal in the Passed and Ready states.

(We can see this by looking at the downstream PartyGovernance.veto function)

It has been confirmed to me by the sponsor that the voteToVeto function should not restrict the situations in which vetos can occur.

The impact of this issue is that the situations in which vetos can occur is more limited than it should be. Users should have the ability to veto proposals even in the Passed and Ready states but they don’t.

Proof of Concept

By looking at the VetoProposal.voteToVeto function we see that it’s only possible to call the function when the proposal is in the Voting state. Otherwise the function reverts:

Link

// Check that proposal is active
(
    PartyGovernance.ProposalStatus proposalStatus,
    PartyGovernance.ProposalStateValues memory proposalValues
) = party.getProposalStateInfo(proposalId);
if (proposalStatus != PartyGovernance.ProposalStatus.Voting)
    revert ProposalNotActiveError(proposalId);

But when we look at the PartyGovernance.veto function which is called downstream and which implements the actual veto functionality (the VetoProposal.voteToVeto function is only a wrapper) we can see that it allows vetoing in the Voting, Passed and Ready states:

Link

function veto(uint256 proposalId) external onlyHost onlyDelegateCall {
    // Setting votes to -1 indicates a veto.
    ProposalState storage info = _proposalStateByProposalId[proposalId];
    ProposalStateValues memory values = info.values;


    {
        ProposalStatus status = _getProposalStatus(values);
        // Proposal must be in one of the following states.
        if (
            status != ProposalStatus.Voting &&
            status != ProposalStatus.Passed &&
            status != ProposalStatus.Ready
        ) {
            revert BadProposalStatusError(status);
        }
    }


    // -1 indicates veto.
    info.values.votes = VETO_VALUE;
    emit ProposalVetoed(proposalId, msg.sender);
}

Therefore we can see that the VetoProposal.voteToVeto function restricts the vetoing functionality too much.

Users are not able to veto in the Passed and Ready states even though it should be possible.

Tools Used

VSCode

Recommended Mitigation Steps

The issue can be fixed by allowing the VetoProposal.voteToVeto function to be called in the Passed and Ready states as well.

Fix:

diff --git a/contracts/proposals/VetoProposal.sol b/contracts/proposals/VetoProposal.sol
index 780826f..38410f6 100644
--- a/contracts/proposals/VetoProposal.sol
+++ b/contracts/proposals/VetoProposal.sol
@@ -30,7 +30,11 @@ contract VetoProposal {
             PartyGovernance.ProposalStatus proposalStatus,
             PartyGovernance.ProposalStateValues memory proposalValues
         ) = party.getProposalStateInfo(proposalId);
-        if (proposalStatus != PartyGovernance.ProposalStatus.Voting)
+        if (
+            proposalStatus != PartyGovernance.ProposalStatus.Voting
+            && proposalStatus != PartyGovernance.ProposalStatus.Passed
+            && proposalStatus != PartyGovernance.ProposalStatus.Ready
+           )
             revert ProposalNotActiveError(proposalId);  

---

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