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Process Quality Review (0.7)


Final score:81%
Date:14 Oct 2021
Audit Process:version 0.7
Author:Nick of DeFiSafety
PQR Score:81%



  • Previous report scored 84% on 4 May 2021  - Previous report scored 85% on August 2020

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

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


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: 20%

They are available at website https://github.com/makerdao/spells-mainnet/blob/master/src/test/addresses_mainnet.sol, as indicated in the Appendix. The documents contain no mention of non-token contract addresses and digging through 250 repositories yielded few results.

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

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

Answer: 100%

Activity is more than 10 transactions a day on contract Maker: MCD Join DAI, as indicated in the Appendix.

Percentage Score Guidance:
More than 10 transactions a day
More than 10 transactions a week
More than 10 transactions a month
Less than 10 transactions a month
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:
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.
For teams with private repositories.

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

Answer: 100%

At 251 repositories with some containing in excess of 800 commits, Maker's development history can be tolerated.

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

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

Answer: Yes

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".



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

Basic software functions are documented.

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

Answer: 100%

Maker's documentation is impressive and covers all deployed contracts in a highly organised fashion.

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

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

Answer: 36%

Code examples are in the Appendix. As per the SLOC, there is 36% commenting to code (CtC).

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

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

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

Answer: 60%

There is clear association from the documents to the code, but there is no explicit traceability to the implementation.

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



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

Answer: 100%

Code examples are in the Appendix. As per the SLOC, there is 222% testing to code (TtC).

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:
TtC > 120% Both unit and system test visible
TtC > 80% Both unit and system test visible
TtC < 80% Some tests visible
No tests obvious

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

Answer: 50%

Code coverage is mentioned, but proof could not be found. Nevertheless, there's evidently heavy testing on this protocol.

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

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

Answer: Yes

Scripts/Instructions location: https://github.com/makerdao/spells-mainnet#test

14. Report of the results (%)

Answer: 0%

No test report was found.

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

15. Formal Verification test done (%)

Answer: 100%

Although Maker says that they have undergone Formal Verification testing, there exists no link to a report of any kind. However we will score it as complete.

16. Stress Testing environment (%)

Answer: 100%

Maker uses Kovan testnet.



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%

Maker has undergone multiple audits for many of its strapiucts, all of which were conducted shortly before or after contract deployment.

Percentage Score Guidance:
Multiple Audits performed before deployment and results public and implemented or not required
Single audit performed before deployment and results public and implemented or not required
Audit(s) performed after deployment and no changes required. Audit report is public
Audit(s) performed after deployment and changes needed but not implemented
No audit performed
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%

Maker offers a $100K HackerOne bug bounty program.

Percentage Score Guidance:
Bounty is 10% TVL or at least $1M AND active program (see below)
Bounty is 5% TVL or at least 500k AND active program
Bounty is 5% TVL or at least 500k
Bounty is 100k or over AND active program
Bounty is 100k or over
Bounty is 50k or over AND active program
Bounty is 50k or over
Bug bounty program bounty is less than 50k
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


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%

Maker's Governance and access controls documentations are clearly outlined in their docs. There is in-depth information regarding the governance smart contracts' functionalities, and the admin controls thereof.

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

20. Is the information clear and complete (%)

Answer: 90%

a) All contracts are clearly labelled as upgradeable (or not) -- 30% -- contracts are labelled as upgradeable.  b) The type of ownership is clearly indicated (OnlyOwner / MultiSig / Defined Roles) -- 30% -- governance is indicated as the owner.  c) The capabilities for change in the contracts are described -- 30% -- there is detailed information as to what can change in these contracts.

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: 30%

This information is not in clear, non-software language, and does not pertain to users' investments' safety.

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

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

Answer: 80%

A pause control is well documented, though there is no mention of testing. The GitHub repository seems to be mostly deprecated.

Percentage Score Guidance:
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
Pause control(s) explained clearly but no evidence of regular tests
Pause controls mentioned with no detail on capability or tests
Pause control not documented or explained


 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.

1pragma solidity >=0.6.12;
23interface VatLike {
4    function move(address,address,uint256) external;
5    function flux(bytes32,address,address,uint256) external;
6    function ilks(bytes32) external returns (uint256, uint256, uint256, uint256, uint256);
7    function suck(address,address,uint256) external;
910interface PipLike {
11    function peek() external returns (bytes32, bool);
1314interface SpotterLike {
15    function par() external returns (uint256);
16    function ilks(bytes32) external returns (PipLike, uint256);
1819interface DogLike {
20    function chop(bytes32) external returns (uint256);
21    function digs(bytes32, uint256) external;
2324interface ClipperCallee {
25    function clipperCall(address, uint256, uint256, bytes calldata) external;
2728interface AbacusLike {
29    function price(uint256, uint256) external view returns (uint256);
3132contract Clipper {
33    // --- Auth ---
34    mapping (address => uint256) public wards;
35    function rely(address usr) external auth { wards[usr] = 1; emit Rely(usr); }
36    function deny(address usr) external auth { wards[usr] = 0; emit Deny(usr); }
37    modifier auth {
38        require(wards[msg.sender] == 1, "Clipper/not-authorized");
39        _;
40    }
4142    // --- Data ---
43    bytes32  immutable public ilk;   // Collateral type of this Clipper
44    VatLike  immutable public vat;   // Core CDP Engine
4546    DogLike     public dog;      // Liquidation module
47    address     public vow;      // Recipient of dai raised in auctions
48    SpotterLike public spotter;  // Collateral price module
49    AbacusLike  public calc;     // Current price calculator
5051    uint256 public buf;    // Multiplicative factor to increase starting price                  [ray]
52    uint256 public tail;   // Time elapsed before auction reset                                 [seconds]
53    uint256 public cusp;   // Percentage drop before auction reset                              [ray]
54    uint64  public chip;   // Percentage of tab to suck from vow to incentivize keepers         [wad]
55    uint192 public tip;    // Flat fee to suck from vow to incentivize keepers                  [rad]
56    uint256 public chost;  // Cache the ilk dust times the ilk chop to prevent excessive SLOADs [rad]
5758    uint256   public kicks;   // Total auctions
59    uint256[] public active;  // Array of active auction ids
6061    struct Sale {
62        uint256 pos;  // Index in active array
63        uint256 tab;  // Dai to raise       [rad]
64        uint256 lot;  // collateral to sell [wad]
65        address usr;  // Liquidated CDP
66        uint96  tic;  // Auction start time
67        uint256 top;  // Starting price     [ray]
68    }
69    mapping(uint256 => Sale) public sales;
7071    uint256 internal locked;
7273    // Levels for circuit breaker
74    // 0: no breaker
75    // 1: no new kick()
76    // 2: no new kick() or redo()
77    // 3: no new kick(), redo(), or take()
78    uint256 public stopped = 0;
7980    // --- Events ---
81    event Rely(address indexed usr);
82    event Deny(address indexed usr);
8384    event File(bytes32 indexed what, uint256 data);
85    event File(bytes32 indexed what, address data);
8687    event Kick(
88        uint256 indexed id,
89        uint256 top,
90        uint256 tab,
91        uint256 lot,
92        address indexed usr,
93        address indexed kpr,
94        uint256 coin
95    );
96    event Take(
97        uint256 indexed id,
98        uint256 max,
99        uint256 price,
100        uint256 owe,
101        uint256 tab,
102        uint256 lot,
103        address indexed usr
104    );
105    event Redo(
106        uint256 indexed id,
107        uint256 top,
108        uint256 tab,
109        uint256 lot,
110        address indexed usr,
111        address indexed kpr,
112        uint256 coin
113    );
114115    event Yank(uint256 id);
116117    // --- Init ---
118    constructor(address vat_, address spotter_, address dog_, bytes32 ilk_) public {
119        vat     = VatLike(vat_);
120        spotter = SpotterLike(spotter_);
121        dog     = DogLike(dog_);
122        ilk     = ilk_;
123        buf     = RAY;
124        wards[msg.sender] = 1;
125        emit Rely(msg.sender);
126    }
127128    // --- Synchronization ---
129    modifier lock {
130        require(locked == 0, "Clipper/system-locked");
131        locked = 1;
132        _;
133        locked = 0;
134    }
135136    modifier isStopped(uint256 level) {
137        require(stopped < level, "Clipper/stopped-incorrect");
138        _;
139    }
140141    // --- Administration ---
142    function file(bytes32 what, uint256 data) external auth lock {
143        if      (what == "buf")         buf = data;
144        else if (what == "tail")       tail = data;           // Time elapsed before auction reset
145        else if (what == "cusp")       cusp = data;           // Percentage drop before auction reset
146        else if (what == "chip")       chip = uint64(data);   // Percentage of tab to incentivize (max: 2^64 - 1 => 18.xxx WAD = 18xx%)
147        else if (what == "tip")         tip = uint192(data);  // Flat fee to incentivize keepers (max: 2^192 - 1 => 6.277T RAD)
148        else if (what == "stopped") stopped = data;           // Set breaker (0, 1, 2, or 3)
149        else revert("Clipper/file-unrecognized-param");
150        emit File(what, data);
151    }
152    function file(bytes32 what, address data) external auth lock {
153        if (what == "spotter") spotter = SpotterLike(data);
154        else if (what == "dog")    dog = DogLike(data);
155        else if (what == "vow")    vow = data;
156        else if (what == "calc")  calc = AbacusLike(data);
157        else revert("Clipper/file-unrecognized-param");
158        emit File(what, data);
159    }
160161    // --- Math ---
162    uint256 constant BLN = 10 **  9;
163    uint256 constant WAD = 10 ** 18;
164    uint256 constant RAY = 10 ** 27;
165166    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
167        z = x <= y ? x : y;
168    }
169    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
170        require((z = x + y) >= x);
171    }
172    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
173        require((z = x - y) <= x);
174    }
175    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
176        require(y == 0 || (z = x * y) / y == x);
177    }
178    function wmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
179        z = mul(x, y) / WAD;
180    }
181    function rmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
182        z = mul(x, y) / RAY;
183    }
184    function rdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
185        z = mul(x, RAY) / y;
186    }
187188    // --- Auction ---
189190    // get the price directly from the OSM
191    // Could get this from rmul(Vat.ilks(ilk).spot, Spotter.mat()) instead, but
192    // if mat has changed since the last poke, the resulting value will be
193    // incorrect.
194    function getFeedPrice() internal returns (uint256 feedPrice) {
195        (PipLike pip, ) = spotter.ilks(ilk);
196        (bytes32 val, bool has) = pip.peek();
197        require(has, "Clipper/invalid-price");
198        feedPrice = rdiv(mul(uint256(val), BLN), spotter.par());
199    }
200201    // start an auction
202    // note: trusts the caller to transfer collateral to the contract
203    // The starting price `top` is obtained as follows:
204    //
205    //     top = val * buf / par
206    //
207    // Where `val` is the collateral's unitary value in USD, `buf` is a
208    // multiplicative factor to increase the starting price, and `par` is a
209    // reference per DAI.
210    function kick(
211        uint256 tab,  // Debt                   [rad]
212        uint256 lot,  // Collateral             [wad]
213        address usr,  // Address that will receive any leftover collateral
214        address kpr   // Address that will receive incentives
215    ) external auth lock isStopped(1) returns (uint256 id) {
216        / Input validation
217        require(tab  >          0, "Clipper/zero-tab");
218        require(lot  >          0, "Clipper/zero-lot");
219        require(usr != address(0), "Clipper/zero-usr");
220        id = ++kicks;
221        require(id   >          0, "Clipper/overflow");
222223        active.push(id);
224225        sales[id].pos = active.length - 1;
226227        sales[id].tab = tab;
228        sales[id].lot = lot;
229        sales[id].usr = usr;
230        sales[id].tic = uint96(block.timestamp);
231232        uint256 top;
233        top = rmul(getFeedPrice(), buf);
234        require(top > 0, "Clipper/zero-top-price");
235        sales[id].top = top;
236237        / incentive to kick auction
238        uint256 _tip  = tip;
239        uint256 _chip = chip;
240        uint256 coin;
241        if (_tip > 0 || _chip > 0) {
242            coin = add(_tip, wmul(tab, _chip));
243            vat.suck(vow, kpr, coin);
244        }

Solidity Contracts


Comments to Code: 756 / 2119 =  36 %

JavaScript Tests


Tests to Code: 4710 / 2119 = 222 %