Immunefi Audit Competitions
Alchemix

31594 - [SC - Insight] RewardPoolManager can only add RewardPoolToken ...

Submitted on May 21st 2024 at 15:49:14 UTC by @hulkvision for Boost | Alchemix

Report ID: #31594

Report type: Smart Contract

Report severity: Insight

Target: https://github.com/alchemix-finance/alchemix-v2-dao/blob/main/src/RewardPoolManager.sol

Impacts:

  • Contract fails to deliver promised returns, but doesn't lose value

Description

Brief/Intro

I have mentioned two issues that would be nice to fix in this report.

  1. RewardPoolManager can only add RewardPoolToken and has a limit of maximum limit of 10 reward tokens and does not have way to remove it.
  2. In VotingEscrow.sol setClaimFee does not have any upper limit check on fee amount set by the admin.

Vulnerability Details #1

RewardPoolManager can only add RewardPoolToken and has a limit of maximum limit of 10 reward tokens and does not have way to remove it, so if a reward token becomes insolvent or its value decreased to zero, the contract will have no way to remove these tokens.

In RewardPoolManager.sol

function _addRewardPoolToken(address token) internal { //@audit-ok
        if (!isRewardPoolToken[token] && token != address(0)) {
            require(rewardPoolTokens.length < MAX_REWARD_POOL_TOKENS, "too many reward pool tokens");

            isRewardPoolToken[token] = true;
            rewardPoolTokens.push(token);
        }
    }

Impact Details #1

  • Contract will not be to remove tokens that have become malicious or their value has decreased to zero.

Vulnerability Detail #2

In VotingEscrow.sol

function setClaimFee(uint256 _claimFeeBps) external { //@audit no upper limit check present
        require(msg.sender == admin, "not admin");
        claimFeeBps = _claimFeeBps;
        emit ClaimFeeUpdated(_claimFeeBps);
    }

setClaimFee function is used by admin to set the claim fee for claiming ALCX rewards early, it is used by RewardsDistributor.sol contract to claim fees. This function does not have a upper limit check present on how much fee can be claimed.

Impact Details #2

  • Allowing arbitrary fee without upper limit could reduce user trust in the protocol.

Proof of Concept

Add this test to src/test/VotingEscrow.t.sol and run test with forge test --mt testPocArbitraryClaimFees --rpc-url $RPC_URL

function testPocArbitraryClaimFees() public {
    veALCX.setClaimFee(1000000000);
        assertEq(veALCX.claimFeeBps(), 1000000000, "incorrect claim fee");
}