Last Man Standing
First Flight #45
Beginner FriendlyFoundrySolidity
100 EXP
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Submission Details
Severity: low
Valid

Incorrect prize amount logged in GameEnded event due to premature pot reset

anchabadze

Description:

The declareWinner() function contains a logic error in the order of operations that causes the GameEnded event to emit incorrect prize amount data.

pendingWinnings[currentKing] = pendingWinnings[currentKing] + pot;
pot = 0; // Reset pot after assigning to winner's pending winnings
​
emit GameEnded(currentKing, pot, block.timestamp, gameRound); // pot is already 0!

The sequence of operations is:

  1. Add pot amount to winner's pending winnings

  2. Reset pot to 0

  3. Emit event with the now-zero pot value

This means the GameEnded event will always log prizeAmount = 0 instead of the actual prize amount that was won, regardless of how much ETH was actually in the pot.

Example:

  • Pot contains 10 ETH when grace period expires

  • Winner should receive 10 ETH prize

  • Event emits: GameEnded(winner, 0, timestamp, round) instead of GameEnded(winner, 10, timestamp, round)

Impact:

External monitoring systems receive false prize amount information

Recommended Mitigation:

Store the pot amount before resetting it, then emit the event with the correct prize value:

function declareWinner() external gameNotEnded {
require(currentKing != address(0), "Game: No one has claimed the throne yet.");
require(block.timestamp >= lastClaimTime + gracePeriod, "Game: Grace period has not expired yet.");
​
gameEnded = true;
// Store the actual prize amount before resetting pot
uint256 prizeAmount = pot;
pendingWinnings[currentKing] = pendingWinnings[currentKing] + pot;
pot = 0; // Reset pot after assigning to winner's pending winnings
​
// Emit event with correct prize amount
emit GameEnded(currentKing, prizeAmount, block.timestamp, gameRound);
}

This ensures the event accurately reflects the actual prize amount won, maintaining data integrity for all external systems monitoring the contract.

Updates

Appeal created

inallhonesty Lead Judge 10 months ago
Submission Judgement Published
Validated
Assigned finding tags:

Game::declareWinner emits GameEnded event with pot = 0 always

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