Rock Paper Scissors

Summary

When players join a game, they transfer 1 RPSW token to the contract. However, when the game is canceled (e.g., via _cancelGame or a timeout) or ends in a tie, the contract mints new tokens to players instead of returning their original tokens. This causes two issues:

• Token Supply Inflation: New tokens are minted even though the original tokens are still locked in the contract.

• Loss of User Funds: The original tokens remain trapped in the contract forever, as the code does not transfer them back. Players lose their deposited tokens permanently.

Vulnerability Details

• In createGameWithToken, players transfer tokens to the contract:

winningToken.transferFrom(msg.sender, address(this), 1);

• In _cancelGame, tokens are minted instead of returned:

winningToken.mint(game.playerA, 1); // Mints new tokens

Impact

• Uncontrolled token inflation.

• Players lose their deposited tokens permanently

Tools Used

Manual code review

Recommendations

• Replace minting with transferring the original locked tokens back to players in _cancelGame and _handleTie. Use transfer instead of mint.

• Ensure the contract holds tokens temporarily and returns them on cancellation.