Wcusdcv3 rewards fix (#1016)

reserve-protocol · Nov 30, 2023 · 3a4ac7c · 3a4ac7c
1 parent 259bdd6
commit 3a4ac7c
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Showing 4 changed files with 23 additions and 8 deletions.
diff --git a/contracts/plugins/assets/compoundv3/CusdcV3Wrapper.sol b/contracts/plugins/assets/compoundv3/CusdcV3Wrapper.sol
@@ -20,14 +20,14 @@ contract CusdcV3Wrapper is ICusdcV3Wrapper, WrappedERC20, CometHelpers {
     /// From cUSDCv3, used in principal <> present calculations
     uint256 public constant TRACKING_INDEX_SCALE = 1e15;
     /// From cUSDCv3, scaling factor for USDC rewards
-    uint64 public constant RESCALE_FACTOR = 1e12;
+    uint256 public constant RESCALE_FACTOR = 1e12;
 
     CometInterface public immutable underlyingComet;
     ICometRewards public immutable rewardsAddr;
     IERC20 public immutable rewardERC20;
 
-    mapping(address => uint64) public baseTrackingIndex;
-    mapping(address => uint64) public baseTrackingAccrued;
+    mapping(address => uint64) public baseTrackingIndex; // uint64 for consistency with CometHelpers
+    mapping(address => uint256) public baseTrackingAccrued; // uint256 to avoid overflow in L:199
     mapping(address => uint256) public rewardsClaimed;
 
     constructor(
@@ -257,7 +257,8 @@ contract CusdcV3Wrapper is ICusdcV3Wrapper, WrappedERC20, CometHelpers {
 
         uint256 indexDelta = uint256(trackingSupplyIndex - baseTrackingIndex[account]);
         uint256 newBaseTrackingAccrued = baseTrackingAccrued[account] +
-            safe64((safe104(balanceOf(account)) * indexDelta) / TRACKING_INDEX_SCALE);
+            (safe104(balanceOf(account)) * indexDelta) /
+            TRACKING_INDEX_SCALE;
 
         uint256 claimed = rewardsClaimed[account];
         uint256 accrued = newBaseTrackingAccrued * RESCALE_FACTOR;
@@ -286,9 +287,7 @@ contract CusdcV3Wrapper is ICusdcV3Wrapper, WrappedERC20, CometHelpers {
         (, uint64 trackingSupplyIndex) = getSupplyIndices();
         uint256 indexDelta = uint256(trackingSupplyIndex - baseTrackingIndex[account]);
 
-        baseTrackingAccrued[account] += safe64(
-            (safe104(accountBal) * indexDelta) / TRACKING_INDEX_SCALE
-        );
+        baseTrackingAccrued[account] += (safe104(accountBal) * indexDelta) / TRACKING_INDEX_SCALE;
         baseTrackingIndex[account] = trackingSupplyIndex;
     }
 

diff --git a/contracts/plugins/assets/compoundv3/ICusdcV3Wrapper.sol b/contracts/plugins/assets/compoundv3/ICusdcV3Wrapper.sol
@@ -51,7 +51,7 @@ interface ICusdcV3Wrapper is IWrappedERC20, IRewardable {
 
     function convertDynamicToStatic(uint256 amount) external view returns (uint104);
 
-    function baseTrackingAccrued(address account) external view returns (uint64);
+    function baseTrackingAccrued(address account) external view returns (uint256);
 
     function baseTrackingIndex(address account) external view returns (uint64);
 

diff --git a/contracts/plugins/assets/yearnv2/YearnV2CurveFiatCollateral.sol b/contracts/plugins/assets/yearnv2/YearnV2CurveFiatCollateral.sol
@@ -77,11 +77,15 @@ contract YearnV2CurveFiatCollateral is CurveStableCollateral {
         return (low, high, 0);
     }
 
+    // solhint-disable no-empty-blocks
+
     /// DEPRECATED: claimRewards() will be removed from all assets and collateral plugins
     function claimRewards() external virtual override {
         // No rewards to claim, everything is part of the pricePerShare
     }
 
+    // solhint-enable no-empty-blocks
+
     // === Internal ===
 
     /// @return {ref/tok} Actual quantity of whole reference units per whole collateral tokens

diff --git a/test/plugins/individual-collateral/compoundv3/CusdcV3Wrapper.test.ts b/test/plugins/individual-collateral/compoundv3/CusdcV3Wrapper.test.ts
@@ -598,6 +598,18 @@ describeFork('Wrapped CUSDCv3', () => {
       )
     })
 
+    it('regression test: able to claim rewards even when they are big without overflow', async () => {
+      // Nov 28 2023: uint64 math in CusdcV3Wrapper contract results in overflow when COMP rewards are even moderately large
+
+      const compToken = <ERC20Mock>await ethers.getContractAt('ERC20Mock', COMP)
+      expect(await compToken.balanceOf(wcusdcV3.address)).to.equal(0)
+      await advanceTime(1000)
+      await enableRewardsAccrual(cusdcV3, bn('2e18')) // enough to revert on uint64 implementation
+
+      await expect(wcusdcV3.connect(bob).claimRewards()).to.emit(wcusdcV3, 'RewardsClaimed')
+      expect(await compToken.balanceOf(bob.address)).to.be.greaterThan(0)
+    })
+
     it('claims rewards and sends to claimer (claimTo)', async () => {
       const compToken = <ERC20Mock>await ethers.getContractAt('ERC20Mock', COMP)
       expect(await compToken.balanceOf(wcusdcV3.address)).to.equal(0)