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Security Audit
Nov 27, 2024
Version 1.0.0
Presented by 0xMacro
This document includes the results of the security audit for Derive's smart contract code as found in the section titled ‘Source Code’. The security audit was performed by the Macro security team from November 11, 2024 to November 13, 2024.
The purpose of this audit is to review the source code of certain Derive Solidity contracts, and provide feedback on the design, architecture, and quality of the source code with an emphasis on validating the correctness and security of the software in its entirety.
Disclaimer: While Macro’s review is comprehensive and has surfaced some changes that should be made to the source code, this audit should not solely be relied upon for security, as no single audit is guaranteed to catch all possible bugs.
The following is an aggregation of issues found by the Macro Audit team:
| Severity | Count | Acknowledged | Won't Do | Addressed |
|---|---|---|---|---|
| Low | 1 | - | - | 1 |
| Code Quality | 4 | 1 | - | 3 |
| Informational | 1 | - | - | - |
Derive was quick to respond to these issues.
Our understanding of the specification was based on the following sources:
The following source code was reviewed during the audit:
55a86af8f7ea3ad4402faf5929e635d714597bb1
Specifically, we audited the following contracts within this repository:
| Source Code | SHA256 |
|---|---|
| src/token/StakedDeriveToken.sol |
|
Note: This document contains an audit solely of the Solidity contracts listed above. Specifically, the audit pertains only to the contracts themselves, and does not pertain to any other programs or scripts, including deployment scripts.
Click on an issue to jump to it, or scroll down to see them all.
We quantify issues in three parts:
This third part – the severity level – is a summary of how much consideration the client should give to fixing the issue. We assign severity according to the table of guidelines below:
| Severity | Description |
|---|---|
|
(C-x) Critical |
We recommend the client must fix the issue, no matter what, because not fixing would mean significant funds/assets WILL be lost. |
|
(H-x) High |
We recommend the client must address the issue, no matter what, because not fixing would be very bad, or some funds/assets will be lost, or the code’s behavior is against the provided spec. |
|
(M-x) Medium |
We recommend the client to seriously consider fixing the issue, as the implications of not fixing the issue are severe enough to impact the project significantly, albiet not in an existential manner. |
|
(L-x) Low |
The risk is small, unlikely, or may not relevant to the project in a meaningful way. Whether or not the project wants to develop a fix is up to the goals and needs of the project. |
|
(Q-x) Code Quality |
The issue identified does not pose any obvious risk, but fixing could improve overall code quality, on-chain composability, developer ergonomics, or even certain aspects of protocol design. |
|
(I-x) Informational |
Warnings and things to keep in mind when operating the protocol. No immediate action required. |
|
(G-x) Gas Optimizations |
The presented optimization suggestion would save an amount of gas significant enough, in our opinion, to be worth the development cost of implementing it. |
The StakedDeriveToken contract overrides the _update() function used on each transfer to skip the voting units transfer on the contract to handle the deallocation and redemption logic properly with the adjusted end amounts:
function _update(address from, address to, uint amount) internal override {
require(from == address(0) || transferWhitelist[from] || transferWhitelist[to], TransferNotAllowed());
// We explicitly skip the ERC20VotesUpgradeable._update() call here as we want to preserve votes for tokens
// that are allocated to usages
ERC20Upgradeable._update(from, to, amount);
if (from == address(0)) {
uint supply = totalSupply();
uint cap = _maxSupply();
if (supply > cap) {
revert ERC20ExceededSafeSupply(supply, cap);
}
}
// We don't want to transfer voting units when allocating/deallocating, and instead handle those cases manually.
// Note: we have to manually transfer voting units whenever funds are sent to the
if (to == address(this) || from == address(this)) return;
_transferVotingUnits(from, to, amount);
}
Reference: StakedDeriveToken.sol#L455-473
However, if a user directly transfers their stDRV tokens to the contract address, not through the intended allocate or redeem functions, they will lose their tokens but retain their voting power, as the _transferVotingUnits call is skipped. This renders an edge case where users maintain their voting power without the tokens in their balance. It’s worth pointing out that these votes can not be delegated as the _getVotingUnits works as intended.
Remediations to Consider:
Consider ensuring the origin of the transfer is the contract on the early return in _update() by checking the reentrancy guard is entered:
if ((to == address(this) && ReentrancyGuardUpgradeable._reentrancyGuardEntered())
|| from == address(this)) return;
getDeriveByVestingDuration()
In StakedDeriveToken, getDeriveByVestingDuration() logic could include the equality on line 123 to avoid unnecessary code execution. Since the duration == maxRedeemDuration also can be calculated with this simple operation:
// capped to maxRedeemDuration
-- if (duration **>** maxRedeemDuration) {
++ if (duration **>=** maxRedeemDuration) {
return amount * maxRedeemRatio / 100;
}
Reference: StakedDeriveToken.sol#L123-125
SafeERC20 library
The _convert and _finalizeRedeem functions use safeTransferFrom and safeTransfer to transfer deriveToken to and from the user. However, since deriveToken is a standard ERC20 token that behaves as intended, using SafeERC20 for these transfers is unnecessary. Moreover, directly using transfer and transferFrom instead of their "safe" versions reduces gas costs.
convertTo cannot be called by contracts
The convertTo function explicitly prevents contracts from calling it:
function convertTo(uint amount, address to) external override nonReentrant {
>> require(address(msg.sender).code.length == 0, CannotConvertToFromSmartContract());
_convert(amount, to);
}
Reference: StakedDeriveToken.sol#L239
Restricting the convertTo function to EOAs only and not allowing any contracts such as smart accounts from calling it is an unnecessary limitation. Consider removing the above require statement.
When initiating a redeem call through redeem(), the contract stores in an array, each pending redemption later to be finalized by its index location through finalizeRedeem() and cancelRedeem(). These functions rely on order execution, and if multiple calls are included in the same block with valid indexes, they could be reorganized with a different execution order than expected.
Macro makes no warranties, either express, implied, statutory, or otherwise, with respect to the services or deliverables provided in this report, and Macro specifically disclaims all implied warranties of merchantability, fitness for a particular purpose, noninfringement and those arising from a course of dealing, usage or trade with respect thereto, and all such warranties are hereby excluded to the fullest extent permitted by law.
Macro will not be liable for any lost profits, business, contracts, revenue, goodwill, production, anticipated savings, loss of data, or costs of procurement of substitute goods or services or for any claim or demand by any other party. In no event will Macro be liable for consequential, incidental, special, indirect, or exemplary damages arising out of this agreement or any work statement, however caused and (to the fullest extent permitted by law) under any theory of liability (including negligence), even if Macro has been advised of the possibility of such damages.
The scope of this report and review is limited to a review of only the code presented by the Derive team and only the source code Macro notes as being within the scope of Macro’s review within this report. This report does not include an audit of the deployment scripts used to deploy the Solidity contracts in the repository corresponding to this audit. Specifically, for the avoidance of doubt, this report does not constitute investment advice, is not intended to be relied upon as investment advice, is not an endorsement of this project or team, and it is not a guarantee as to the absolute security of the project. In this report you may through hypertext or other computer links, gain access to websites operated by persons other than Macro. Such hyperlinks are provided for your reference and convenience only, and are the exclusive responsibility of such websites’ owners. You agree that Macro is not responsible for the content or operation of such websites, and that Macro shall have no liability to your or any other person or entity for the use of third party websites. Macro assumes no responsibility for the use of third party software and shall have no liability whatsoever to any person or entity for the accuracy or completeness of any outcome generated by such software.