fix: prevent underflow

alpaca-finance · Aug 22, 2024 · c8dea5f · c8dea5f
1 parent e68fa02
commit c8dea5f
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/contracts/8.19/xALPACAv2RevenueDistributor/xALPACAv2Rewarder.sol b/contracts/8.19/xALPACAv2RevenueDistributor/xALPACAv2Rewarder.sol
@@ -167,7 +167,9 @@ contract xALPACAv2Rewarder is IxALPACAv2Rewarder, OwnableUpgradeable, Reentrancy
     //   Meaning user eligible for 25,000 rewards in this harvest
     int256 _accumulatedRewards = ((_userAmount * pool.accRewardPerShare) / ACC_REWARD_PRECISION).toInt256();
 
-    uint256 _pendingRewards = (_accumulatedRewards - user.rewardDebt).toUint256();
+    uint256 _pendingRewards = _accumulatedRewards > user.rewardDebt
+      ? (_accumulatedRewards - user.rewardDebt).toUint256()
+      : 0;
 
     user.rewardDebt = _accumulatedRewards;
     if (user.amount != _userAmount) {
@@ -236,8 +238,12 @@ contract xALPACAv2Rewarder is IxALPACAv2Rewarder, OwnableUpgradeable, Reentrancy
     }
 
     uint256 _totalUserAmount = IxALPACAv2RevenueDistributor(xALPACAv2RevenueDistributor).getUserTotalAmountOf(_user);
-    return
-      (((_totalUserAmount * _accRewardPerShare) / ACC_REWARD_PRECISION).toInt256() - _userInfo.rewardDebt).toUint256();
+    int256 _userAccumReward = ((_totalUserAmount * _accRewardPerShare) / ACC_REWARD_PRECISION).toInt256();
+
+    if (_userAccumReward < _userInfo.rewardDebt) {
+      return 0;
+    }
+    return (_userAccumReward - _userInfo.rewardDebt).toUint256();
   }
 
   /// @dev Perform the actual updatePool