Sturdy contest - Cityscape's results

Gas Optimizations

Looping optimizations

for (uint256 i = 0; i < length; i++) {
      assetYields[i].asset = assets[i];
      if (i != length - 1) {
        // Distribute yieldAmount based on percent of asset volume
        assetYields[i].amount = _totalYieldAmount.percentMul(
          volumes[i].mul(PercentageMath.PERCENTAGE_FACTOR).div(totalVolume)
        );
        extraYieldAmount = extraYieldAmount.sub(assetYields[i].amount);
      } else {
        // without calculation, set remained extra amount
        assetYields[i].amount = extraYieldAmount;
      }
    }

proposed change:

for (uint256 i; i < length;) {
      assetYields[i].asset = assets[i];
      if (i != length - 1) {
        // Distribute yieldAmount based on percent of asset volume
        assetYields[i].amount = _totalYieldAmount.percentMul(
          volumes[i].mul(PercentageMath.PERCENTAGE_FACTOR).div(totalVolume)
        );
        extraYieldAmount = extraYieldAmount.sub(assetYields[i].amount);
      } else {
        // without calculation, set remained extra amount
        assetYields[i].amount = extraYieldAmount;
      }
      ++i;
    }

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/YieldManager.sol#L156-L168

for (uint256 i = 0; i < assetYields.length; i++) {
      if (assetYields[i].amount > 0) {
        uint256 _amount = _convertToStableCoin(assetYields[i].asset, assetYields[i].amount);
        // 3. deposit Yield to pool for suppliers
        _depositYield(assetYields[i].asset, _amount);
      }
    }

proposed change:

for (uint256 i; i < assetYields.length;) {
      if (assetYields[i].amount > 0) {
        uint256 _amount = _convertToStableCoin(assetYields[i].asset, assetYields[i].amount);
        // 3. deposit Yield to pool for suppliers
        _depositYield(assetYields[i].asset, _amount);
        ++i;
      }
    }

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/YieldManager.sol#L130-L136

for (uint256 i = 0; i < _count; i++) {
      address asset = _assetsList[_offset + i];
      require(asset != address(0), Errors.UL_INVALID_INDEX);
      uint256 _amount = IERC20Detailed(asset).balanceOf(address(this));
      _convertAssetToExchangeToken(asset, _amount);
    }

proposed change:

for (uint256 i; i < _count;) {
      address asset = _assetsList[_offset + i];
      require(asset != address(0), Errors.UL_INVALID_INDEX);
      uint256 _amount = IERC20Detailed(asset).balanceOf(address(this));
      _convertAssetToExchangeToken(asset, _amount);
      ++i;
    }

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/YieldManager.sol#L125-L125

for (uint256 i = 0; i < extraRewardsLength; i++) {
      address _extraReward = IConvexBaseRewardPool(baseRewardPool).extraRewards(i);
      address _rewardToken = IRewards(_extraReward).rewardToken();
      _transferYield(_rewardToken);
    }
	

proposed change:

for (uint256 i; i < extraRewardsLength;) {
      address _extraReward = IConvexBaseRewardPool(baseRewardPool).extraRewards(i);
      address _rewardToken = IRewards(_extraReward).rewardToken();
      _transferYield(_rewardToken);
      ++i;
    }

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/ConvexCurveLPVault.sol#L106-L110

Use ≠0 instead of > 0

if (assetYields[i].amount > 0) {

proposed change:

if (assetYields[i].amount != 0) {

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/YieldManager.sol#L131-L131

if (_vaultFee > 0) 

proposed change:

if (_vaultFee != 0) 

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/ConvexCurveLPVault.sol#L75-L75

Using memory instead of storage

internal
    override
    returns (address, uint256)
  {
    // receive Curve LP Token from user //@audit put curveLPToken,convexBooster,internalAssetToken into mem
    require(_asset == curveLPToken, Errors.VT_COLLATERAL_DEPOSIT_INVALID);
    TransferHelper.safeTransferFrom(curveLPToken, msg.sender, address(this), _amount);

    // deposit Curve LP Token to Convex
    IERC20(curveLPToken).safeApprove(convexBooster, _amount);
    IConvexBooster(convexBooster).deposit(convexPoolId, _amount, true);

    // mint
    SturdyInternalAsset(internalAssetToken).mint(address(this), _amount);//@audit safeMint()?
    IERC20(internalAssetToken).safeApprove(address(_addressesProvider.getLendingPool()), _amount);

    return (internalAssetToken, _amount);
  }

proposed change:

internal
    override
    returns (address, uint256)
  {
    // receive Curve LP Token from user //@audit put curveLPToken,convexBooster,internalAssetToken into mem
    require(_asset == curveLPToken, Errors.VT_COLLATERAL_DEPOSIT_INVALID);
    address _curveLPToken = curveLPToken;
    address _convexBooster = convexBooster;
    address _internalAssetToken = internalAssetToken;

    TransferHelper.safeTransferFrom(_curveLPToken, msg.sender, address(this), _amount);

    // deposit Curve LP Token to Convex
    IERC20(_curveLPToken).safeApprove(_convexBooster, _amount);
    IConvexBooster(_convexBooster).deposit(convexPoolId, _amount, true);

    // mint
    SturdyInternalAsset(_internalAssetToken).mint(address(this), _amount);//@audit safeMint()?
    IERC20(_internalAssetToken).safeApprove(address(_addressesProvider.getLendingPool()), _amount);

    return (_internalAssetToken, _amount);
  }

https://github.com/code-423n4/2022-05-sturdy/blob/78f51a7a74ebe8adfd055bdbaedfddc05632566f/smart-contracts/ConvexCurveLPVault.sol#L131-L149