TwentyOne
First Flight #29
Beginner FriendlyGameFiFoundrySolidity
100 EXP
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Submission Details
Severity: medium
Invalid

Inefficient Clearing of Dynamic Arrays in the endGame Function

bryanconquer

Summary

The endGame function of the TwentyOne contract uses the delete operation to reset the dynamic arrays playersDeck[player].playersCards and dealersDeck[player].dealersCards. However, this approach does not completely clear the arrays' underlying storage. While the delete operation sets the length of the arrays to zero, it does not remove residual data in storage, leading to potential inefficiencies in subsequent array operations.

Vulnerability Details

delete playersDeck[player].playersCards and delete dealersDeck[player].dealersCards only set the length of the arrays to zero, leaving residual storage intact.

Residual storage data increases gas costs for future operations and may result in unintended behaviors.

Impact

Inefficient gas usage during subsequent operations.

  • Potential for stale data causing unexpected behavior in edge cases.

Tools Used

Recommendations

Replace the delete operation with an explicit truncation of the dynamic arrays to ensure complete removal of data from storage

function endGame(address player, bool playerWon) internal {
// Clear the player's cards by truncating the array
while (playersDeck[player].playersCards.length > 0) {
playersDeck[player].playersCards.pop();
}
​
// Clear the dealer's cards by truncating the array
while (dealersDeck[player].dealersCards.length > 0) {
dealersDeck[player].dealersCards.pop();
}
​
// Clear the available deck
delete availableCards[player]; // Assuming this is an array that doesn't require manual truncation
​
// Handle player winnings
if (playerWon) {
payable(player).transfer(2 ether);
emit FeeWithdrawn(player, 2 ether);
}
}
​
Updates

Lead Judging Commences

inallhonesty Lead Judge 11 months ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity

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