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

Player cannot join the game because `Game::claimThrone` have a wrong equation check, makes the protocol useless

vegazeronos

Player cannot join the game because Game::claimThrone have a wrong equation check, makes the protocol useless

Description

  • Player who wants to join the game should use Game::claimThrone and the player cannot be the king if they want to join the game.

  • Sadly, the require check should be checking if the player is the Current King. But it is not Checking right. The current checking is using a wrong equation which lead to everybody cannot use the protocol

function claimThrone() external payable gameNotEnded nonReentrant {
require(msg.value >= claimFee, "Game: Insufficient ETH sent to claim the throne.");
@> require(msg.sender == currentKing, "Game: You are already the king. No need to re-claim.");

Risk

Likelihood:

  • Everytime player want to join the game, they cannot

Impact:

  • Everyone cannot join the game because of this wrong equation, the game cannot run even at the beginning

  • The protocol cannot run even at the start of their launch


Proof of Concept

  1. Player 1 want to join the game

  2. Sadly, he / she cannot join because of the wrong equation

function test_firstPlayerCannotJoin() public {
vm.startPrank(player1);
uint256 claimAmount = game.claimFee();
vm.expectRevert();
game.claimThrone{value: claimAmount}();
vm.stopPrank();
}
​

Recommended Mitigation

Please consider to change the equation from require(msg.sender == currentKing...) into this code require(msg.sender != currentKing...)

function claimThrone() external payable gameNotEnded nonReentrant {
require(msg.value >= claimFee, "Game: Insufficient ETH sent to claim the throne.");
- 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 Lead Judge 28 days ago
Submission Judgement Published
Validated
Assigned finding tags:

Game::claimThrone `msg.sender == currentKing` check is busted

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