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Security Audit
September 29, 2023
Version 1.0.0
Presented by 0xMacro
This document includes the results of the security audit for Kwenta's smart contract code as found in the section titled ‘Source Code’. The security audit was performed by the Macro security team from September 27, 2023.
The purpose of this audit is to review the source code of certain Kwenta 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 |
|---|---|---|---|---|
| Code Quality | 1 | - | - | 1 |
| Gas Optimization | 2 | 2 | - | - |
Kwenta 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:
8f7e7cd77f27f8f4e79b09a54bcb153afba6339e
Specifically, we audited the following contracts within this repository:
| Source Code | SHA256 |
|---|---|
| src/Account.sol |
|
| src/interfaces/IAccount.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. |
These changes added an additional command type, PERPS_V2_SET_MIN_KEEPER_FEE, which has a value of 16. In _dispatch() it goes through a branching path of conditional statements based on the passed in commandIndex. Where this command was added, a comment explaining that commandIndex 14 and 15 have already been checked was removed.
// commandIndex 14 & 15 valid and already checked
Reference: Account.sol diff
Removal of this comment makes the code confusing as the checks jump from
commandIndex < 14 to commandIndex == 16
} else if (commandIndex < 14) {
// **code**
} else if (commandIndex == 16) {
Reference: Account.sol#L452-L490
Remediations to Consider
Add back in the comment that was removed to make it more clear those commands aren’t skipped.
PERPS_V2_SET_MIN_KEEPER_FEE earlier in _dispatch()
The intention of the command PERPS_V2_SET_MIN_KEEPER_FEE is to update Synthetix’s min keeper fee to ensure that the fee is sufficient to incentivize the execution of core synthetix functions. This command is expected to be bundled before commands that require a keeper to later complete the execution, like for delayed order executions. Since this may be called frequently alongside the command PERPS_V2_SUBMIT_DELAYED_ORDER, it should be checked earlier relative to the expected frequency of its use compared to other commands, as the more checks required for a given command increases its gas cost.
Remediations to Consider
Reorder when PERPS_V2_SET_MIN_KEEPER_FEE is executed to reflect how often it is expected to be used relative to other commands to reduce the average gas cost of interacting with an account.
Acknowledged with no action taken
ConditionalOrder struct can be packed more efficiently
The ConditionalOrder struct is stored when a conditional order is placed, and used when making a conditional order.
struct ConditionalOrder {
bytes32 marketKey;
int256 marginDelta;
int256 sizeDelta;
uint256 targetPrice;
bytes32 gelatoTaskId;
ConditionalOrderTypes conditionalOrderType;
uint256 desiredFillPrice;
bool reduceOnly;
}
Reference: IAccount.sol#L89-L98
Currently it uses 8 storage slots, one for each of the parameters. However, since ConditionalOrderTypes is an enum, it only uses 1 byte of storage. If this was reordered to be next to reduceOnly, they would share the same storage slot and reduce the number of storage writes to 7.
It is important to note, however, that since this would change how the ConditionalOrder data is stored and read, and prior values have been set by existing accounts, upgrading accounts to use the updated struct would cause active conditional orders to be read improperly, preventing their execution and cancelation.
Remediations to Consider
If a new factory is deployed with updated accounts, consider reordering the ConditionalOrder struct values to have conditionalOrderType and reduceOnly next to each other, so they will be packed into the same storage slot.
Acknowledged with no action taken
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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 Kwenta 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.