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Security Audit
May 20, 2024
Version 1.0.0
Presented by 0xMacro
This document includes the results of the security audit for Compound's smart contract code as found in the section titled ‘Source Code’. The security audit was performed by the Macro security team from April 30, 2024 to May 6, 2023. For a total of three audit days.
The purpose of this audit is to review the source code of certain Compound 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 | 6 | - | 1 | 5 |
Compound was quick to respond to these issues.
Our understanding of the specification was based on the following sources:
Quark is an Ethereum smart contract wallet system designed to run custom code with each transaction.
The following source code was reviewed during the audit:
9d8f07d571298b448852bf63997b9b5278725f3e
9b334b0239c6a10a7a34578948ca6dc86db444e0
Specifically, we audited the following contracts with the 9d8f07d571298b448852bf63997b9b5278725f3 commit hash:
| Source Code | SHA256 |
|---|---|
| ./src/codejar/src/CodeJar.sol |
|
| ./src/codejar/src/CodeJarFactory.sol |
|
| ./src/quark-core/src/QuarkScript.sol |
|
| ./src/quark-core/src/QuarkStateManager.sol |
|
| ./src/quark-core/src/QuarkWallet.sol |
|
| ./src/quark-core/src/QuarkWalletStandalone.sol |
|
| ./src/quark-core/src/interfaces/IHasSignerExecutor.sol |
|
| ./src/quark-core/src/interfaces/IQuarkWallet.sol |
|
| ./src/quark-core/src/periphery/BatchExecutor.sol |
|
| ./src/quark-core-scripts/src/Ethcall.sol |
|
| ./src/quark-core-scripts/src/Multicall.sol |
|
| ./src/quark-core-scripts/src/Paycall.sol |
|
| ./src/quark-core-scripts/src/UniswapFlashLoan.sol |
|
| ./src/quark-core-scripts/src/UniswapFlashSwapExactOut.sol |
|
| ./src/quark-core-scripts/src/lib/UniswapFactoryAddress.sol |
|
| ./src/quark-core-scripts/src/vendor/chainlink/AggregatorV3Interface.sol |
|
| ./src/quark-core-scripts/src/vendor/uniswap_v3_periphery/PoolAddress.sol |
|
| ./src/quark-factory/src/QuarkFactory.sol |
|
| ./src/quark-proxy/src/QuarkMinimalProxy.sol |
|
| ./src/quark-proxy/src/QuarkWalletProxyFactory.sol |
|
Additionally, we audited the following contracts with the 9b334b0239c6a10a7a34578948ca6dc86db444e commit hash. (QuoteCall addition and minor Paycall changes):
| Source Code | SHA256 |
|---|---|
| ./src/quark-core-scripts/src/Paycall.sol |
|
| ./src/quark-core-scripts/src/Quotecall.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.
maxDeltaPercentage_
GAS_OVERHEAD should be adapted for different scripts
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. |
Quotecall and Paycall scripts use Chainlink data feeds to fetch the native chain asset prices and calculate the gas amount needed for the transaction. However, there are no sanity checks implemented to the returned answer in the latestRoundData() call.
Remediations to Consider
Consider adding proper input validation to ensure the returned price.
Consider encoding the opDigest array using encodePacked directly in getDigestForMultiQuarkOperation() to avoid looping an static type dynamic array:
function getDigestForMultiQuarkOperation(bytes32[] memory opDigests) public pure returns (bytes32) {
bytes memory encodedOpDigests;
for (uint256 i = 0; i < opDigests.length; ++i) {
encodedOpDigests = abi.encodePacked(encodedOpDigests, opDigests[i]);
}
bytes32 structHash = keccak256(abi.encode(MULTI_QUARK_OPERATION_TYPEHASH, keccak256(encodedOpDigests)));
return keccak256(abi.encodePacked("\x19\x01", MULTI_QUARK_OPERATION_DOMAIN_SEPARATOR, structHash));
}
Reference: QuarkWallet.sol#L294-302
Suggested code snippet:
function getDigestForMultiQuarkOperation(bytes32[] memory opDigests) public pure returns (bytes32) {
bytes32 encodedOpDigests = keccak256(abi.encodePacked(opDigests));
bytes32 structHash = keccak256(abi.encode(MULTI_QUARK_OPERATION_TYPEHASH, encodedOpDigests));
return keccak256(abi.encodePacked("\x19\x01", MULTI_QUARK_OPERATION_DOMAIN_SEPARATOR, structHash));
}
The Multicall core script uses an unchecked block to increment the loop iteration variable. Consider increasing this in the for statement declaration to keep it consistent with the rest of the codebase.
Consider declaring the native token decimals as a constant in Paycall and Quotecall scripts.
// Note: Assumes the native token has 18 decimals
divisorScale = 10
** uint256(
18 + AggregatorV3Interface(nativeTokenBasedPriceFeedAddress).decimals()
- IERC20Metadata(paymentTokenAddress).decimals()
);
Reference: Paycall.sol#L53-58
codeExist() function in CodeJar.sol refers to runtime code as the input parameter code:
* @param code The runtime bytecode of the code to check
Reference: CodeJar.sol#L47
maxDeltaPercentage_
In QuoteCall script, the parameter maxDeltaPercentage set during the contract’s initialization is not bounded to any value. If it is set to a value high value, it could spend a considerably higher amount of tokens than the actual gas spent. Consider limiting this value to a fair amount, for example, 1e18, which is a 100% variation of the actual amount spent.
We would rather not explicitly enforce a bound on this value, as any bounds we pick would be subjective and arbitrary.
GAS_OVERHEAD should be adapted for different scripts
Paycall and Quotecall scripts declare a GAS_OVERHEAD amount to account for the gas used by the contract itself outside the gas metrics being tracked in the run() logic. However, both scripts have the same value being used, even if Quotecall has less untracked logic in it. Consider adapting this constant for different scripts.
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The scope of this report and review is limited to a review of only the code presented by the Compound 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.