CEther Manual Review Findings

CER-01M: Impossible Autonomous Deployment

Description:

The code within the constructor of the contract was adjusted and thus cannot be deployed independently as the admin variable is no longer temporarily adjusted to bypass the check within initialize.

Example:

Copy
20function initialize(ComptrollerInterface comptroller_,
21                    InterestRateModel interestRateModel_,
22                    uint initialExchangeRateMantissa_,
23                    string memory name_,
24                    string memory symbol_,
25                    uint8 decimals_,
26                    uint256 reserveFactorMantissa_,
27                    uint256 adminFeeMantissa_) public {
28    // CToken initialize does the bulk of the work
29    super.initialize(comptroller_, interestRateModel_, initialExchangeRateMantissa_, name_, symbol_, decimals_, reserveFactorMantissa_, adminFeeMantissa_);
30}

Recommendation:

We advise that the ramifications of this are evaluated and if desired to be kept as is explicitly mentioned so within the constructor's description.

Alleviation:

In response to this finding Rari specified that the CEther token is not meant to be deployable independently as is the case with the main Compound implementation and thus this exhibit can be considered null.

CER-02M: Potentially Breaking Functionality

Description:

The transfer opcode assigns a static gas amount to the external call that transfers funds outwards which can be changed in a consequent fork of Ethereum and thus cause such transfer calls to fail.

Example:

Copy
137function doTransferOut(address payable to, uint amount) internal {
138    /* Send the Ether, with minimal gas and revert on failure */
139    to.transfer(amount);
140}

Recommendation:

We advise that an OpenZeppelin wrapper implementation is instead used safely, such as the sendValue function of the Address library, to ensure compatibility at the EVM level perpetually.

Alleviation:

The transfer call instances were replaced by to.call.value(amount)("") invocations ensuring the code segment is future proof. We should note that a side-effect of this is that the Checks-Effects-Interactions pattern should be ensured to be sufficiently applied wherever doTransferOut is invoked as the new method forwards gas and allows more complex calls to be performed by the recipient.