MyCut

AI First Flight #8
Beginner FriendlyFoundry
EXP
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Submission Details
Severity: medium
Valid

`Pot::closePot` with zero claimants pays the manager cut but strands the entire claimant portion in the pot

Description


closePothandles the case where nobody claimed incorrectly. When claimants.length == 0(no player called claimCutduring the 90-day window) but remainingRewards > 0, the function still takes the manager cut, computes a claimantCut, but the distribution loop never executes — so the entire claimant portion is never sent anywhere.


if (remainingRewards > 0) {
uint256 managerCut = remainingRewards / managerCutPercent;
i_token.transfer(msg.sender, managerCut); // manager still paid
​
uint256 claimantCut = (remainingRewards - managerCut) / i_players.length;
for (uint256 i = 0; i < claimants.length; i++) { // @> claimants.length == 0 -> body never runs
_transferReward(claimants[i], claimantCut);
}
// @> (remainingRewards - managerCut) is never distributed and remains stuck in the Pot
}
```
​
## Risk
​
**Likelihood: Medium**
​
- "Nobody claimed in time" is a normal, expected end-state for a pot (it is exactly why the manager-cut/close mechanism exists). No special setup is required.
​
**Impact: Medium**
​
- With zero claimants, the manager receives 10% but the remaining ~90% (`remainingRewards - managerCut`) has no recipient and is left permanently locked in the `Pot` — there is no function to recover it. Loss/lock of the bulk of the pot whenever no one claims.
​
## Proof of Concept
​
```solidity
// players = [A, B], rewards = [100, 100], totalRewards = 200 (funded). Nobody calls claimCut.
// After 90 days, closePot():
// remainingRewards = 200 > 0
// managerCut = 20 -> sent to manager
// claimantCut = (200 - 20) / 2 = 90, but claimants.length == 0 -> loop does nothing
// => 180 tokens remain stuck in the Pot forever.
```
​
## Recommended Mitigation
​
Explicitly handle the zero-claimants case — e.g. send the undistributed remainder to the manager/fee address (or allow the admin to reclaim it) when there are no claimants:
​
```solidity
if (claimants.length == 0) {
i_token.safeTransfer(feeAddress, remainingRewards); // nothing to split; return the pool
remainingRewards = 0;
return;
}
```
}
}
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge about 4 hours ago
Submission Judgement Published
Validated
Assigned finding tags:

[M-01] Incorrect Handling of Zero Claimants in `closePot()` Function

## Description In the \`closePot\` function, if the number of claimants is zero, the remaining rewards intended for distribution among claimants may not be properly reclaimed by the Contest Manager. The \`claimantCut\` is calculated using the length of the \`i_players\` array instead of the \`claimants\` array, which could lead to incorrect distribution. Additionally, the function does not have a mechanism to handle the scenario where there are zero claimants, resulting in the potential loss of rewards. ## Vulnerability Details Specifically, when there are no claimants: - The manager's cut is calculated but only a portion or none of the remaining rewards is transferred back to the Contest Manager. - The rewards intended for claimants (\`claimantCut\`) are not distributed because the loop iterating over \`claimants\` does not execute, but there's also no fallback to reclaim these rewards. ## Proof of Concept Add this test in the TestMyCut.t.sol: ```markdown function testClosePotWithZeroClaimants() public mintAndApproveTokens { vm.startPrank(user); // Step 1: Create a new contest contest = ContestManager(conMan).createContest(players, rewards, IERC20(weth), totalRewards); // Step 2: Fund the pot ContestManager(conMan).fundContest(0); // Step 3: Move forward in time by 90 days so the pot can be closed vm.warp(block.timestamp + 90 days); // Step 4: Close the pot with 0 claimants uint256 managerBalanceBefore = weth.balanceOf(user); ContestManager(conMan).closeContest(contest); uint256 managerBalanceAfter = weth.balanceOf(user); vm.stopPrank(); // Step 5: Assert that the Contest Manager received all the remaining rewards // Since there are no claimants, the manager should receive all remaining rewards assertEq(managerBalanceAfter, managerBalanceBefore + totalRewards, "Manager did not reclaim all rewards after closing pot with zero claimants."); ``` In the test `testClosePotWithZeroClaimants`, after closing a pot with zero claimants, the Contest Manager is unable to reclaim all the remaining rewards: ```markdown ├─ [9811] ContestManager::closeContest(Pot: [0x43e82d2718cA9eEF545A591dfbfD2035CD3eF9c0]) │ ├─ [8956] Pot::closePot() │ │ ├─ [5288] 0x5929B14F2984bBE5309c2eC9E7819060C31c970f::transfer(ContestManager: [0x7BD1119CEC127eeCDBa5DCA7d1Bd59986f6d7353], 0) │ │ │ ├─ emit Transfer(from: Pot: [0x43e82d2718cA9eEF545A591dfbfD2035CD3eF9c0], to: ContestManager: [0x7BD1119CEC127eeCDBa5DCA7d1Bd59986f6d7353], value: 0) ``` ## Impact - This bug can lead to incomplete recovery of rewards by the Contest Manager. If no participants claim their rewards, a significant portion of the remaining tokens could remain locked in the contract indefinitely, leading to financial loss and inefficient fund management. - And All the reward is lost except from the little 10 % the manager gets because there was no mechanism to claim the remainingReward ## Recommendations - Adjust Calculation Logic: Modify the \`claimantCut\` calculation to divide by \`claimants.length\` instead of \`i_players.length\`. This ensures that only the claimants are considered when distributing the remaining rewards. - Handle Zero Claimants: Implement a check to determine if there are zero claimants. If true, all remaining rewards should be transferred back to the Contest Manager to ensure no tokens are left stranded in the contract. Example ```markdown if (claimants.length == 0) { i_token.transfer(msg.sender, remainingRewards); } else { for (uint256 i = 0; i < claimants.length; i++) { \_transferReward(claimants[i], claimantCut); } } ``` This approach ensures that in the event of zero claimants, all remaining rewards are securely returned to the Contest Manager.

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