Rewards will be lost when totalStaked == 0

[c4-bot-8]

Lines of code

https://github.com/code-423n4/2024-02-uniswap-foundation/blob/5a2761c8277541a24bc551fbd624413b384bea94/src/UniStaker.sol#L230

Vulnerability details

Impact

if totalStaked == 0, no rewards are distributed within this period. Unfortunately, all undistributed rewards are lost forever.

Proof of Concept

  function rewardPerTokenAccumulated() public view returns (uint256) {
    if (totalStaked == 0) return rewardPerTokenAccumulatedCheckpoint;

    return rewardPerTokenAccumulatedCheckpoint
      + (scaledRewardRate * (lastTimeRewardDistributed() - lastCheckpointTime)) / totalStaked;
  }

  function _checkpointGlobalReward() internal {
    rewardPerTokenAccumulatedCheckpoint = rewardPerTokenAccumulated();
    lastCheckpointTime = lastTimeRewardDistributed();
  }

  function lastTimeRewardDistributed() public view returns (uint256) {
    if (rewardEndTime <= block.timestamp) return rewardEndTime;
    else return block.timestamp;
  }

As above, rewardPerTokenAccumulatedCheckpoint is not updated but lastCheckpointTime is updated. As a result, all rewards during this period are lost forever.

Tools Used

Manual

Recommended Mitigation Steps

Revise the logic.

Assessed type

Uniswap

[c4-judge]

MarioPoneder marked the issue as duplicate of #9

[c4-judge]

MarioPoneder marked the issue as duplicate of #369

[c4-judge]

MarioPoneder marked the issue as unsatisfactory:
Invalid