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Synthetix PQ

85%

Process Quality Review (0.7)

Synthetix PQ

Final score:85%
Date:27 Apr 2021
Audit Process:version 0.7
Author:Rex of DeFiSafety
PQR Score:85%

PASS

Scoring Appendix

The final review score is indicated as a percentage. The percentage is calculated as Achieved Points due to MAX Possible Points. For each element the answer can be either Yes/No or a percentage. For a detailed breakdown of the individual weights of each question, please consult this document.

The blockchain used by this protocol
BnB Smart Chain
Ethereum
#QuestionAnswer
100%
1.100%
2.100%
3.Yes
4.100%
5.Yes
96%
6.Yes
7.Yes
8.100%
9.65%
10.100%
84%
11.100%
12.96%
13.Yes
14.70%
15.0%
16.100%
96%
17.100%
18.70%
26%
19.100%
20.40%
21.0%
22.0%
Total:85%

Very simply, the audit looks for the following declarations from the developer's site. With these declarations, it is reasonable to trust the smart contracts.

  • Here is my smart contract on the blockchain
  • You can see it matches a software repository used to develop the code
  • Here is the documentation that explains what my smart contract does
  • Here are the tests I ran to verify my smart contract
  • Here are the audit(s) performed to review my code by third party experts

This report is for informational purposes only and does not constitute investment advice of any kind, nor does it constitute an offer to provide investment advisory or other services. Nothing in this report shall be considered a solicitation or offer to buy or sell any security, token, future, option or other financial instrument or to offer or provide any investment advice or service to any person in any jurisdiction. Nothing contained in this report constitutes investment advice or offers any opinion with respect to the suitability of any security, and the views expressed in this report should not be taken as advice to buy, sell or hold any security. The information in this report should not be relied upon for the purpose of investing. In preparing the information contained in this report, we have not taken into account the investment needs, objectives and financial circumstances of any particular investor. This information has no regard to the specific investment objectives, financial situation and particular needs of any specific recipient of this information and investments discussed may not be suitable for all investors.

Any views expressed in this report by us were prepared based upon the information available to us at the time such views were written. The views expressed within this report are limited to DeFiSafety and the author and do not reflect those of any additional or third party and are strictly based upon DeFiSafety, its authors, interpretations and evaluation of relevant data. Changed or additional information could cause such views to change. All information is subject to possible correction. Information may quickly become unreliable for various reasons, including changes in market conditions or economic circumstances.

This completed report is copyright (c) DeFiSafety 2021. Permission is given to copy in whole, retaining this copyright label.

Code And Team

100%

This section looks at the code deployed on the Mainnet that gets reviewed and its corresponding software repository. The document explaining these questions is here.

1. Are the executing code addresses readily available? (%)

Answer: 100%

Actually finding the addresses was not immediately direct, but was simple enough. There is no developer page on the website. After clicking on the GitHub icon on the footer of the webpage and reading the "readme" file, I could link to the docs for synthetics. From their the addresses were clearly in the Developer Resource section. The page has all the details that could be desired.

Percentage Score Guidance:
100%
Clearly labelled and on website, docs or repo, quick to find
70%
Clearly labelled and on website, docs or repo but takes a bit of looking
40%
Addresses in mainnet.json, in discord or sub graph, etc
20%
Address found but labeling not clear or easy to find
0%
Executing addresses could not be found

2. Is the code actively being used? (%)

Answer: 100%

Activity is well over 10 internal transactions a day on contract Address Resolver, as indicated in the Appendix.

Percentage Score Guidance:
100%
More than 10 transactions a day
70%
More than 10 transactions a week
40%
More than 10 transactions a month
10%
Less than 10 transactions a month
0%
No activity

3. Is there a public software repository? (Y/N)

Answer: Yes

Is there a public software repository with the code at a minimum, but also normally test and scripts. Even if the repository was created just to hold the files and has just 1 transaction, it gets a "Yes". For teams with private repositories, this answer is "No"

Score Guidance:
Yes
There is a public software repository with the code at a minimum, but also normally test and scripts. Even if the repository was created just to hold the files and has just 1 transaction.
No
For teams with private repositories.

4. Is there a development history visible? (%)

Answer: 100%

With 3,783 commits and 155 branches, this is a very healthy repo.

This metric checks if the software repository demonstrates a strong steady history. This is normally demonstrated by commits, branches and releases in a software repository. A healthy history demonstrates a history of more than a month (at a minimum).

Percentage Score Guidance:
100%
Any one of 100+ commits, 10+branches
70%
Any one of 70+ commits, 7+branches
50%
Any one of 50+ commits, 5+branches
30%
Any one of 30+ commits, 3+branches
0%
Less than 2 branches or less than 30 commits

5. Is the team public (not anonymous)? (Y/N)

Answer: Yes

The teams names and roles are clearly in the GitHub repo.

For a "Yes" in this question, the real names of some team members must be public on the website or other documentation (LinkedIn, etc). If the team is anonymous, then this question is a "No".

Documentation

96%

This section looks at the software documentation. The document explaining these questions is here.

6. Is there a whitepaper? (Y/N)

Answer: Yes

7. Are the basic software functions documented? (Y/N)

Answer: Yes

8. Does the software function documentation fully (100%) cover the deployed contracts? (%)

Answer: 100%

Full documentation is available.

Percentage Score Guidance:
100%
All contracts and functions documented
80%
Only the major functions documented
79 - 1%
Estimate of the level of software documentation
0%
No software documentation

9. Are there sufficiently detailed comments for all functions within the deployed contract code (%)

Answer: 65%

The first impression is to give a very high score for commenting because comments are clear, detailed and included where they add value. The percentage of code to commenting is actually low compared to many other applications at 31%. Numbers in excess of 70% have been seen on well-documented other applications. Part of the reason may be that there is just so much code included. At 9,000 lines over 45 modules this is one of the largest applications audited to date. Based on the commenting the code percentage score of about 45% would be in line with other audits. Given the quality I will increase it to 65%.

The Comments to Code (CtC) ratio is the primary metric for this score.

Percentage Score Guidance:
100%
CtC > 100 Useful comments consistently on all code
90 - 70%
CtC > 70 Useful comment on most code
60 - 20%
CtC > 20 Some useful commenting
0%
CtC < 20 No useful commenting

10. Is it possible to trace from software documentation to the implementation in code (%)

Answer: 100%

Each function is clearly documented. Next of the documentation is a link directly to the source code. This is exactly the type of traceability we are looking for.

Percentage Score Guidance:
100%
Clear explicit traceability between code and documentation at a requirement level for all code
60%
Clear association between code and documents via non explicit traceability
40%
Documentation lists all the functions and describes their functions
0%
No connection between documentation and code

Testing

84%

11. Full test suite (Covers all the deployed code) (%)

Answer: 100%

Clearly there is a full test suite. Test line to code ratio is 375%

This score is guided by the Test to Code ratio (TtC). Generally a good test to code ratio is over 100%. However the reviewers best judgement is the final deciding factor.

Percentage Score Guidance:
100%
TtC > 120% Both unit and system test visible
80%
TtC > 80% Both unit and system test visible
40%
TtC < 80% Some tests visible
0%
No tests obvious

12. Code coverage (Covers all the deployed lines of code, or explains misses) (%)

Answer: 96%

Code coverage for the deployed release is 96% as per GitHub CodeCov.

Percentage Score Guidance:
100%
Documented full coverage
99 - 51%
Value of test coverage from documented results
50%
No indication of code coverage but clearly there is a reasonably complete set of tests
30%
Some tests evident but not complete
0%
No test for coverage seen

13. Scripts and instructions to run the tests? (Y/N)

Answer: Yes

Sythetix has a full document on their automated test procedures.

14. Report of the results (%)

Answer: 70%

The automated code coverage report answers most of the questions. What is missing is a stand alone report indicating the pass of all tests and describing the few misses. But clearly, most questions are answered.

Percentage Score Guidance:
100%
Detailed test report as described below
70%
GitHub code coverage report visible
0%
No test report evident

15. Formal Verification test done (%)

Answer: 0%

No evidence of Formal Verification was found.

16. Stress Testing environment (%)

Answer: 100%

The address page includes test addresses for Ropsten, Rinkeby and Kovan. The Ropsten address' at a minimum are still in regular use.

Security

96%

This section looks at the 3rd party software audits done. It is explained in this document.

17. Did 3rd Party audits take place? (%)

Answer: 100%

The audit history page shows regular audits taking place. There were two audits in 2021 and eight audits in 2020 alone (before mid-August) from two independent auditors. The audit results and documentation appears meticulous and complete.

Percentage Score Guidance:
100%
Multiple Audits performed before deployment and results public and implemented or not required
90%
Single audit performed before deployment and results public and implemented or not required
70%
Audit(s) performed after deployment and no changes required. Audit report is public
50%
Audit(s) performed after deployment and changes needed but not implemented
20%
No audit performed
0%
Audit Performed after deployment, existence is public, report is not public and no improvements deployed OR smart contract address not found, (where question 1 is 0%)
Deduct 25% if code is in a private repo and no note from auditors that audit is applicable to deployed code.

18. Is the bug bounty acceptable high? (%)

Answer: 70%

200k active program

Percentage Score Guidance:
100%
Bounty is 10% TVL or at least $1M AND active program (see below)
90%
Bounty is 5% TVL or at least 500k AND active program
80%
Bounty is 5% TVL or at least 500k
70%
Bounty is 100k or over AND active program
60%
Bounty is 100k or over
50%
Bounty is 50k or over AND active program
40%
Bounty is 50k or over
20%
Bug bounty program bounty is less than 50k
0%
No bug bounty program offered
An active program means that a third party (such as Immunefi) is actively driving hackers to the site. An inactive program would be static mentions on the docs.

Access Controls

26%

This section covers the documentation of special access controls for a DeFi protocol. The admin access controls are the contracts that allow updating contracts or coefficients in the protocol. Since these contracts can allow the protocol admins to "change the rules", complete disclosure of capabilities is vital for user's transparency. It is explained in this document.

19. Can a user clearly and quickly find the status of the access controls (%)

Answer: 100%

Percentage Score Guidance:
100%
Clearly labelled and on website, docs or repo, quick to find
70%
Clearly labelled and on website, docs or repo but takes a bit of looking
40%
Access control docs in multiple places and not well labelled
20%
Access control docs in multiple places and not labelled
0%
Admin Control information could not be found

20. Is the information clear and complete (%)

Answer: 40%
  • Clearly the contracts are upgradeable, which is clearly mentioned in the Governance section but it never says exactly which so implicitly it is all. So score 20%  - The type of Ownership is clearly effectively Only Owner as the foundation controls all updates except I saw other articles that said the foundation was replaced by DAO's but there are no links to DAO's, so score 10%  - The capabilities for change seem very high, but no limits are mentioned. There are no specifics, so score 10%  - Final score = 20+10+10 = 40%

Percentage Score Guidance:
All the contracts are immutable -- 100% OR
a) All contracts are clearly labelled as upgradeable (or not) -- 30% AND
b) The type of ownership is clearly indicated (OnlyOwner / MultiSig / Defined Roles) -- 30% AND
c) The capabilities for change in the contracts are described -- 30%

21. Is the information in non-technical terms that pertain to the investments (%)

Answer: 0%

There is no information on the capabilities of the admin controls or their impact on investments.

Percentage Score Guidance:
100%
All the contracts are immutable
90%
Description relates to investments safety and updates in clear, complete non-software language
30%
Description all in software specific language
0%
No admin control information could be found

22. Is there Pause Control documentation including records of tests (%)

Answer: 0%

No pause controls are mentioned.

Percentage Score Guidance:
100%
All the contracts are immutable or no pause control needed and this is explained OR Pause control(s) are clearly documented and there is records of at least one test within 3 months
80%
Pause control(s) explained clearly but no evidence of regular tests
40%
Pause controls mentioned with no detail on capability or tests
0%
Pause control not documented or explained

Appendices

 The author of this review is Rex of DeFi Safety.

Email: rex@defisafety.com
Twitter: @defisafety

I started with Ethereum just before the DAO and that was a wonderful education.  It showed the importance of code quality. The second Parity hack also showed the importance of good process.  Here my aviation background offers some value. Aerospace knows how to make reliable code using quality processes.
I was coaxed to go to EthDenver 2018 and there I started SecuEth.org with Bryant and Roman. We created guidelines on good processes for blockchain code development. We got EthFoundation funding to assist in their development Process Quality Reviews are an extension of the SecurEth guidelines that will further increase the quality processes in Solidity and Vyper development. DeFiSafety is my full time gig and we are working on funding vehicles for a permanent staff.

1// https://docs.synthetix.io/contracts/FeePool
2contract FeePool is Owned, Proxyable, SelfDestructible, LimitedSetup, MixinResolver, IFeePool {
3    using SafeMath for uint;
4    using SafeDecimalMath for uint;
56    // Exchange fee may not exceed 10%.
7    uint public constant MAX_EXCHANGE_FEE_RATE = 1e18 / 10;
89    // Where fees are pooled in sUSD.
10    address public constant FEE_ADDRESS = 0xfeEFEEfeefEeFeefEEFEEfEeFeefEEFeeFEEFEeF;
1112    // sUSD currencyKey. Fees stored and paid in sUSD
13    bytes32 private sUSD = "sUSD";
1415    // This struct represents the issuance activity that's happened in a fee period.
16    struct FeePeriod {
17        uint64 feePeriodId;
18        uint64 startingDebtIndex;
19        uint64 startTime;
20        uint feesToDistribute;
21        uint feesClaimed;
22        uint rewardsToDistribute;
23        uint rewardsClaimed;
24    }
2526    // A staker(mintr) can claim from the previous fee period (7 days) only.
27    // Fee Periods stored and managed from [0], such that [0] is always
28    // the current active fee period which is not claimable until the
29    // public function closeCurrentFeePeriod() is called closing the
30    // current weeks collected fees. [1] is last weeks feeperiod
31    uint8 public constant FEE_PERIOD_LENGTH = 2;
3233    FeePeriod[FEE_PERIOD_LENGTH] private _recentFeePeriods;
34    uint256 private _currentFeePeriod;
3536    // How long a fee period lasts at a minimum. It is required for
37    // anyone to roll over the periods, so they are not guaranteed
38    // to roll over at exactly this duration, but the contract enforces
39    // that they cannot roll over any quicker than this duration.
40    uint public feePeriodDuration = 1 weeks;
41    / The fee period must be between 1 day and 60 days.
42    uint public constant MIN_FEE_PERIOD_DURATION = 1 days;
43    uint public constant MAX_FEE_PERIOD_DURATION = 60 days;
4445    / Users are unable to claim fees if their collateralisation ratio drifts out of target treshold
46    uint public targetThreshold = (1 * SafeDecimalMath.unit()) / 100;
4748       /* ========== MUTATIVE FUNCTIONS ========== */
4950    /**
51     * @notice Logs an accounts issuance data per fee period
52     * @param account Message.Senders account address
53     * @param debtRatio Debt percentage this account has locked after minting or burning their synth
54     * @param debtEntryIndex The index in the global debt ledger. synthetixState.issuanceData(account)
55     * @dev onlyIssuer to call me on synthetix.issue() & synthetix.burn() calls to store the locked SNX
56     * per fee period so we know to allocate the correct proportions of fees and rewards per period
57     */
58    function appendAccountIssuanceRecord(
59        address account,
60        uint debtRatio,
61        uint debtEntryIndex
62    ) external onlyIssuer {
63        feePoolState().appendAccountIssuanceRecord(
64            account,
65            debtRatio,
66            debtEntryIndex,
67            _recentFeePeriodsStorage(0).startingDebtIndex
68        );
6970        emitIssuanceDebtRatioEntry(account, debtRatio, debtEntryIndex, _recentFeePeriodsStorage(0).startingDebtIndex);
71    }
7273    /**
74     * @notice Set the fee period duration
75     */
76    function setFeePeriodDuration(uint _feePeriodDuration) external optionalProxy_onlyOwner {
77        require(_feePeriodDuration >= MIN_FEE_PERIOD_DURATION, "value < MIN_FEE_PERIOD_DURATION");
78        require(_feePeriodDuration <= MAX_FEE_PERIOD_DURATION, "value > MAX_FEE_PERIOD_DURATION");
7980        feePeriodDuration = _feePeriodDuration;
8182        emitFeePeriodDurationUpdated(_feePeriodDuration);
83    }

Solidity Contracts

Language
Files
Lines
Blanks
Comments
Code
Complexity
Solidity
45
9218
1771
1764
5683
546

Comments to Code: 1764 / 5683 =  31 %

JavaScript Tests

Language
Files
Lines
Blanks
Comments
Code
Complexity
JavaScript
42
0
3534
1855
0
477