Submission Details
Severity:
[L-1] Using long loop in `TwentyOne::initializeDeck` might lead to revert `Out of gas` in some cases (due to heavy network traffic or gas-intensive operations)
Summary
In TwentyOne::initializeDeck function there's the loop with 52 iterations that performs storage operations, which are some of the most costly operations in Solidity.
Vulnerability Details
function initializeDeck(address player) internal {
require(
availableCards[player].length == 0,
"Player's deck is already initialized"
);
@> for (uint256 i = 1; i <= 52; i++) {
@> availableCards[player].push(i);
}
}
Impact
The gas already consumed up to the point of the revert is non-refundable.
Tools Used
Manual, Foundry
Recommendations
There's a way to make gas consumption more efficient due to heavy network traffic or gas-intensive operations:
function initializeDeck(address player) internal {
require(
availableCards[player].length == 0,
"Player's deck is already initialized"
);
- for (uint256 i = 1; i <= 52; i++) {
- availableCards[player].push(i);
- }
+ uint256[52] memory deck;
+ for (uint256 i = 0; i < 52; i++) {
+ deck[i] = i + 1;
+ }
+ availableCards[player] = deck;
}
Rewards breakdown
nSLOC
147This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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