Eggstravaganza
First Flight #37
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Submission Details
Severity: low
Valid

[L-01] Incorrectly displays the remaining time until the end of underlying game

vladich0x

Summary

[L-01] Incorrectly displays the remaining time until the end of underlying game

Vulnerability Details

The following function EggHuntGame.sol::getRemainigTime() gives back information of the remaining time until end of the active game. The implementation checks only the current time against endTime. The wrong behavior comes when the game owner terminates earlier the game (before the game duration is expired) and only the state variable gameActive is updated, without resetting endTime. Missing check in EggHuntGame.sol::getRemainigTime() for the state gamActive leads to calculating incorrect remaining time in the game.

function getTimeRemaining() external view returns (uint256) {
// missing game state check
return block.timestamp >= endTime ? 0 : endTime - block.timestamp;
}

Impact

Missing check for the state gameActive within functionEggHuntGame.sol::getRemainigTime() leads to:

  • incorrect calculations of remaining time in the game when the game is terminated earlier than the duration is expired

  • misleading the active players and other potential participant that there is still a running game, when the game is terminated earlier of duration expiration

Tools Used

Manual review
Foundry

PoC

Add the following test to EggHuntGameTest.t.sol.

function testGetTimeRemainingAfterGameEnded() public {
uint256 duration = 100;
uint256 start = block.timestamp;
uint256 endTime = start + duration;
console.log("startTime: ", start);
console.log("expected endTime: ", start + duration);
​
vm.prank(game.owner());
game.startGame(duration);
​
vm.warp(block.timestamp + duration / 2);
vm.prank(game.owner());
game.endGame();
​
console.log("game ended: ", block.timestamp);
assertTrue(block.timestamp < endTime);
​
uint256 remaining = game.getTimeRemaining();
console.log("remaining time: ", remaining);
}

Recommendations

Update the following check within EggHuntGame.sol::getTimeRemaining() in order to calculate remaining time in the game correct. This way the calculations will be correct, even the game has been terminated before the durataion is expired.

function getTimeRemaining() external view returns (uint256) {
- return block.timestamp >= endTime ? 0 : endTime - block.timestamp;
+ return block.timestamp >= endTime || !gameActive ? 0 : endTime - block.timestamp;
}
Updates

Lead Judging Commences

m3dython Lead Judge 5 months ago
Submission Judgement Published
Validated
Assigned finding tags:

Incomplete end game handling

Incorrect values reported when a game is ended early

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