Submission Details
Severity:
claimThrone()` will always fail
Description
After the game starts, player1 tries to claim the throne by calling claimThrone(),
but it always fails due to the incorrect require statement in
https://github.com/CodeHawks-Contests/2025-07-last-man-standing/blob/47d9d19a78acb52270269f4bff1568b87eb81a96/src/Game.sol#L188
Proof of Concept
Add this to Game.t.sol:
function testclaimThrone0() public {
vm.startPrank(player1);
console2.log("currentKing:", game.currentKing());
console2.log("player1:", player1);
game.claimThrone{value: 0.1 ether}();
console2.log("the new currentKing:", game.currentKing());
vm.stopPrank();
}
Then run:
forge test --match-test testclaimThrone0 -vv
Output
Ran 1 test for test/Game.t.sol:GameTest
[FAIL: Game: You are already the king. No need to re-claim.] testclaimThrone0() (gas: 52371)
Logs:
currentKing: 0x0000000000000000000000000000000000000000
player1: 0x7026B763CBE7d4E72049EA67E89326432a50ef84
Suite result: FAILED. 0 passed; 1 failed; 0 skipped; finished in 1.85ms (155.00µs CPU time)
Ran 1 test suite in 11.89ms (1.85ms CPU time): 0 tests passed, 1 failed, 0 skipped (1 total test)
Failing tests:
Encountered 1 failing test in test/Game.t.sol:GameTest
[FAIL: Game: You are already the king. No need to re-claim.] testclaimThrone0() (gas: 52371)
As we can see, currentKing is 0x0000000000000000000000000000000000000000,
and player1 is 0x7026B763CBE7d4E72049EA67E89326432a50ef84,
but it still throws the error: You are already the king. No need to re-claim.
Recommended Mitigation
- require(msg.sender == currentKing, "Game: You are already the king. No need to re-claim.");
+ require(msg.sender != currentKing, "Game: You are already the king. No need to re-claim.");
Updates
Appeal created
inallhonesty about 1 month ago
Submission Judgement Published Assigned finding tags:
Game::claimThrone `msg.sender == currentKing` check is busted
Rewards breakdown
nSLOC
181This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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