Ethos Reserve contest - 0x73696d616f's results

CollateralConfig.sol

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/CollateralConfig.sol

Allowed in the struct Config is not necessary

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/CollateralConfig.sol#L27

The allowed property in the struct Config is not required, since the other properties can be checked to verify if the collateral is allowed or not (check if decimals > 0, for example).

Properties in the struct Config can be packed

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/CollateralConfig.sol#L27

Currently the properties are not packed, taking whole slots unnecessarily. I suggest packing into the following (or similar)

struct Config {
   bool allowed;
   uint24 decimals;
   uint112 MCR;
   uint112 CCR;
}

Use a getter for the whole Config struct

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/CollateralConfig.sol#L27

Some places use all of the properties in the Config struct (except allowed, but as I mentioned previously, this one is not even required), so a getter for the whole struct is cheaper.

BorrowerOperations.sol

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol

It's not necessary to store both lqtyStaking and lqtyStakingAddress, one can be casted to the other

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L34 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L35

Instead of storing all the contract addresses, a hash of the addresses concatenated could be stored instead, reducing sread operations

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L174 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L175 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L181 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L206 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L226 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L232 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L426 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L524 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L738 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/Dependencies/LiquityBase.sol#L36 from https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/Dependencies/LiquityBase.sol https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/Dependencies/LiquityBase.sol#L56 from https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/Dependencies/LiquityBase.sol

For example, in openTrove, collateralConfig, troveManager, activePool, lusdToken, priceFeed, defaultPool, lqtyStaking and sortedTroves are read from storage. These gas costs could be reduced greatly from storing the hash of the addresses concatenated and then providing the addresses as arguments and hashing them.

Activepool.sol

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol

Use vars.currentAllocated instead of yieldingAmount[_collateral] in function rebalance(...)

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol#L263 Saves a storage read.

collAmount[_collateral] can be cached in function rebalance(...)

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol#L257 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol#L288 Saves a storage read.

LQTYStaking.sol

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol

In function stake, looping over allowed collaterals twice

https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol#L104 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol#L114 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol#L118

Inside the aforementioned function, _getPendingCollateralGain(...) and updateUserSnapshots(...) are being called, which results in looping over the allowed collaterals twice. It should be possible to use only 1 loop here.