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Bancor V3

98%

Previous versions

Process Quality Review (0.8)

Bancor V3

Final score:98%
Date:08 Jun 2022
Audit Process:version 0.8
Author:Nick
PQR Score:98%

PASS

Protocol Website:https://bancor.network

Hack History

Date:16 Jun 2021
Details: Bancor discovered a bug in their own contract after deployment and hacked themselves in order to save funds. This is impressive, and shows good process quality.
Reference Linklink
Date:09 Jul 2018
Details: Bancor lost $23.5m to a hack in 2018. This is well past our penalty point.
Reference Linklink

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
Ethereum
#QuestionAnswer
100%
1.100%
2.100%
3.Yes
4.100%
5.100
100%
6.Yes
7.Yes
8.100%
9.100%
90%
10.100%
11.99%
12.Yes
13.100%
14.No
15.Yes
100%
16.100%
17.100%
97%
18.100%
19.100%
20.100%
21.100%
22.100%
23.80%
24.100%
25.100%
100%
26.100%
27.Yes
28.Yes
Total:98%

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.

Smart Contracts & Team

100%

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

1. Are the smart contract addresses easy to find? (%)

Answer: 100%

They can be found at https://docs.bancor.network/developer-guides/contracts, as indicated in the Appendix.

Percentage Score Guidance:
100%
Clearly labelled and on website, documents or repository, 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. How active is the primary contract? (%)

Answer: 100%

Contract BNT Pool is used more than 10 times a day, 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. Does the protocol have a public software repository? (Y/N)

Answer: Yes

Location: https://github.com/bancorprotocol/

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%

At 3917 commits, there's a veritable bank (or) of development history for users to view.

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)?

Answer: 100

Multiple public team members can be found in the repository or on their twitter page.

Score Guidance:
100%
At least two names can be easily found in the protocol's website, documentation or medium. These are then confirmed by the personal websites of the individuals / their linkedin / twitter.
50%
At least one public name can be found to be working on the protocol.
0%
No public team members could be found.

Documentation

100%

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

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

Answer: Yes

Location: https://docs.bancor.network/about-bancor-network/bancor-v3

7. Is the protocol's software architecture documented? (Y/N)

Answer: Yes

This protocol's software architecture is documented in good detail here. A diagram would further help users understand how contracts interact with one another.

Score Guidance:
Yes
The documents identify software architecture and contract interaction through any of the following: diagrams, arrows, specific reference to software functions or a written explanation on how smart contracts interact.
No
Protocols receive a "no" if none of these are included.

8. Does the software documentation fully cover the deployed contracts' source code? (%)

Answer: 100%

There is full coverage of deployed contracts by software function documentation.

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. Is it possible to trace the documented software to its implementation in the protocol's source code? (%)

Answer: 100%

There is complete traceability between software documentation and implemented code. Users can follow documentation to code easily.

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

90%

10. Has the protocol tested their deployed code? (%)

Answer: 100%

Code examples are in the Appendix at the end of this report.. As per the SLOC, there is 409% 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 reviewer's 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

11. How covered is the protocol's code? (%)

Answer: 99%

Bancor documents 99% code coverage.

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 complete set of tests
30%
Some tests evident but not complete
0%
No test for coverage seen

12. Does the protocol provide scripts and instructions to run their tests? (Y/N)

Answer: Yes

Scripts/Instructions location: https://github.com/bancorprotocol/contracts-v3#deployment-tests

Score Guidance:
Yes
Scripts and/or instructions to run tests are available in the testing suite
No
Scripts and/or instructions to run tests are not available in the testing suite

13. Is there a detailed report of the protocol's test results?(%)

Answer: 100%

Test reports are documented in their repository's CI section.

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

14. Has the protocol undergone Formal Verification? (Y/N)

Answer: No

This protocol has not documented formal verification testing for their V3.

Score Guidance:
Yes
Formal Verification was performed and the report is readily available
No
Formal Verification was not performed and/or the report is not readily available.

15. Were the smart contracts deployed to a testnet? (Y/N)

Answer: Yes

This protocol has been deployed to a testnet. This was done in the form of a Beta program.

Score Guidance:
Yes
Protocol has proved their tesnet usage by providing the addresses
No
Protocol has not proved their testnet usage by providing the addresses

Security

100%

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

16. Is the protocol sufficiently audited? (%)

Answer: 100%

Bancor's V3 has undergone one pre-launch audit. A second audit by OpenZeppelin has been recently made public. Despite the second audit being shortly post-release, we will award full points because the code was submitted in advance of release and no critical bugs were identified pre-release. In addition, the contracts have not been updated since the code was submitted for audit - the production version of the contracts remains the same. Normally we penalise protocols that get an audit say 9 months after launch.    Certora and Chain Security security reviews are also scheduled.

Percentage Score Guidance:
100%
Multiple Audits performed before deployment and the audit findings are public and implemented or not required
90%
Single audit performed before deployment and audit findings are public and implemented or not required
70%
Audit(s) performed after deployment and no changes required. The Audit report is public.
65%
Code is forked from an already audited protocol and a changelog is provided explaining why forked code was used and what changes were made. This changelog must justify why the changes made do not affect the audit.
50%
Audit(s) performed after deployment and changes are needed but not implemented.
30%
Audit(s) performed are low-quality and do not indicate proper due diligence.
20%
No audit performed
0%
Audit Performed after deployment, existence is public, report is not public OR smart contract address' not found.
Deduct 25% if the audited code is not available for comparison.

17. Is the bounty value acceptably high (%)

Answer: 100%

This protocol offers an active bug bounty of $1M. This bug bounty is specific to smart contracts.

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 / the bug bounty program is dead
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.

Admin Controls

97%

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.

18. Is the protocol's admin control information easy to find?

Answer: 100%

Bancor's admin control information is quick to find.

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

19. Are relevant contracts clearly labelled as upgradeable or immutable? (%)

Answer: 100%

Each and every contract is upgradeable, and this is stated in their user documentation.

Percentage Score Guidance:
100%
Both the contract documentation and the smart contract code state that the code is not upgradeable or immutable.
80%
All Contracts are clearly labelled as upgradeable (or not)
50%
Code is immutable but not mentioned anywhere in the documentation
0%
Admin control information could not be found

20. Is the type of smart contract ownership clearly indicated? (%)

Answer: 100%

Ownership is clearly detailed in the hands of Bancor DAO's multisig / voting processes.

Percentage Score Guidance:
100%
The type of ownership is clearly indicated in their documentation. (OnlyOwner / MultiSig / etc)
50%
The type of ownership is indicated, but only in the code. (OnlyOwner / MultiSig / etc)
0%
Admin Control information could not be found

21. Are the protocol's smart contract change capabilities described? (%)

Answer: 100%

Smart contract changes are clearly explained. All Bancor contracts are fully upgradeable as per Bancor DAO decisions.

Percentage Score Guidance:
100%
The documentation covers the capabilities for change for all smart contracts
50%
The documentation covers the capabilities for change in some, but not all contracts
0%
The documentation does not cover the capabilities for change in any contract

22. Is the protocol's admin control information easy to understand? (%)

Answer: 100%

This information is in simple language for users to comprehend.

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

23. Is there sufficient Pause Control documentation? (%)

Answer: 80%

 Bancor has good pause control documentation in their documentation Clear information relating to capacities, conditions and more are detailed.

Percentage Score Guidance:
100%
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

24. Is there sufficient Timelock documentation? (%)

Answer: 100%

Bancor does not use a timelock, and this is explained in this location. . There is a (minimum) 5 day proposal, discussion and voting period but once this is completed changes are effected immediately.

Percentage Score Guidance:
100%
Documentation identifies and explains why the protocol does not need a Timelock OR Timelock documentation identifies its duration, which contracts it applies to and justifies this time period.
60%
A Timelock is identified and its duration is specified
30%
A Timelock is identified
0%
No Timelock information was documented

25. Is the Timelock of an adequate length? (Y/N)

Answer: 100%

Bancor does not use a timelock, and this is explained in this location. . There is a (minimum) 5 day proposal, discussion and voting period but once this is completed changes are effected immediately.

Percentage Score Guidance:
100%
Timelock is between 48 hours to 1 week OR justification as to why no Timelock is needed / is outside this length.
50%
Timelock is less than 48 hours or greater than 1 week.
0%
No Timelock information was documented OR no timelock length was identified.

Oracles

100%

This section goes over the documentation that a protocol may or may not supply about their Oracle usage. Oracles are a fundamental part of DeFi as they are responsible for relaying tons of price data information to thousands of protocols using blockchain technology. Not only are they important for price feeds, but they are also an essential component of transaction verification and security. These questions are explained in this document.

26. Is the protocol's Oracle sufficiently documented? (%)

Answer: 100%

Bancor does not use an oracle, and this is stated in their documentation.

Percentage Score Guidance:
100%
If it uses one, the Oracle is specified. The contracts dependent on the oracle are identified. Basic software functions are identified (if the protocol provides its own price feed data). Timeframe of price feeds are identified. OR The reason as to why the protocol does not use an Oracle is identified and explained.
75%
The Oracle documentation identifies both source and timeframe, but does not provide additional context regarding smart contracts.
50%
Only the Oracle source is identified.
0%
No oracle is named / no oracle information is documented.

27. Is front running mitigated by this protocol? (Y/N)

Answer: Yes

Bancor has a 7 day withdraw cooldown period that prevents sandwich attacks being inflicted upon users.

Score Guidance:
Yes
The protocol cannot be front run and there is an explanation as to why OR documented front running countermeasures are implemented.
No
The Oracle documentation identifies both source and timeframe, but does not provide additional context regarding smart contracts.

28. Can flashloan attacks be applied to the protocol, and if so, are those flashloan attack risks mitigated? (Y/N)

Answer: Yes

Due to a 7 day cooldown on liquidity withdrawals, Bancor is not susceptible to flashloan attack.

Score Guidance:
Yes
The protocol's documentation includes information on how they mitigate the possibilities and extents of flash loan attacks.
No
The protocol's documentation does not include any information regarding the mitigation of flash loan attacks.

Appendices

1// SPDX-License-Identifier: SEE LICENSE IN LICENSE
2pragma solidity 0.8.13;
3
4import { Address } from "@openzeppelin/contracts/utils/Address.sol";
5import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
6import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
7import { ReentrancyGuardUpgradeable } from "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
8import { PausableUpgradeable } from "@openzeppelin/contracts-upgradeable/security/PausableUpgradeable.sol";
9
10import { ITokenGovernance } from "@bancor/token-governance/contracts/ITokenGovernance.sol";
11
12import { IVault, ROLE_ASSET_MANAGER } from "./interfaces/IVault.sol";
13import { Upgradeable } from "../utility/Upgradeable.sol";
14import { IERC20Burnable } from "../token/interfaces/IERC20Burnable.sol";
15import { Token } from "../token/Token.sol";
16import { TokenLibrary } from "../token/TokenLibrary.sol";
17
18import { Utils, AccessDenied, NotPayable, InvalidToken } from "../utility/Utils.sol";
19
20abstract contract Vault is IVault, Upgradeable, PausableUpgradeable, ReentrancyGuardUpgradeable, Utils {
21    using Address for address payable;
22    using SafeERC20 for IERC20;
23    using TokenLibrary for Token;
24
25    // the address of the BNT token
26    IERC20 internal immutable _bnt;
27
28    // the address of the BNT token governance
29    ITokenGovernance internal immutable _bntGovernance;
30
31    // the address of the VBNT token
32    IERC20 internal immutable _vbnt;
33
34    // the address of the VBNT token governance
35    ITokenGovernance internal immutable _vbntGovernance;
36
37    // solhint-disable func-name-mixedcase
38
39    /**
40     * @dev a "virtual" constructor that is only used to set immutable state variables
41     */
42    constructor(ITokenGovernance initBNTGovernance, ITokenGovernance initVBNTGovernance)
43        validAddress(address(initBNTGovernance))
44        validAddress(address(initVBNTGovernance))
45    {
46        _bntGovernance = initBNTGovernance;
47        _bnt = initBNTGovernance.token();
48        _vbntGovernance = initVBNTGovernance;
49        _vbnt = initVBNTGovernance.token();
50    }
51
52    /**
53     * @dev initializes the contract and its parents
54     */
55    function __Vault_init() internal onlyInitializing {
56        __Upgradeable_init();
57        __Pausable_init();
58        __ReentrancyGuard_init();
59
60        __Vault_init_unchained();
61    }
62
63    /**
64     * @dev performs contract-specific initialization
65     */
66    function __Vault_init_unchained() internal onlyInitializing {}
67
68    // solhint-enable func-name-mixedcase
69
70    /**
71     * @dev returns the asset manager role
72     */
73    function roleAssetManager() external pure returns (bytes32) {
74        return ROLE_ASSET_MANAGER;
75    }
76
77    // allows execution only by an authorized operation
78    modifier whenAuthorized(
79        address caller,
80        Token token,
81        address payable target,
82        uint256 amount
83    ) {
84        if (!isAuthorizedWithdrawal(caller, token, target, amount)) {
85            revert AccessDenied();
86        }
87
88        _;
89    }
90
91    /**
92     * @dev returns whether withdrawals are currently paused
93     */
94    function isPaused() external view returns (bool) {
95        return paused();
96    }
97
98    /**
99     * @dev pauses withdrawals
100     *
101     * requirements:
102     *
103     * - the caller must have the ROLE_ADMIN privileges
104     */
105    function pause() external onlyAdmin {
106        _pause();
107    }
108
109    /**
110     * @dev unpauses withdrawals
111     *
112     * requirements:
113     *
114     * - the caller must have the ROLE_ADMIN privileges
115     */
116    function unpause() external onlyAdmin {
117        _unpause();
118    }
119
120    /**
121     * @inheritdoc IVault
122     */
123    function withdrawFunds(
124        Token token,
125        address payable target,
126        uint256 amount
127    )
128        external
129        override
130        validAddress(target)
131        nonReentrant
132        whenNotPaused
133        whenAuthorized(msg.sender, token, target, amount)
134    {
135        if (amount == 0) {
136            return;
137        }
138
139        if (token.isNative()) {
140            // using a regular transfer here would revert due to exceeding the 2300 gas limit which is why we're using
141            // call instead (via sendValue), which the 2300 gas limit does not apply for
142            target.sendValue(amount);
143        } else {
144            token.safeTransfer(target, amount);
145        }
146
147        emit FundsWithdrawn({ token: token, caller: msg.sender, target: target, amount: amount });
148    }
149
150    /**
151     * @inheritdoc IVault
152     */
153    function burn(Token token, uint256 amount)
154        external
155        nonReentrant
156        whenNotPaused
157        whenAuthorized(msg.sender, token, payable(address(0)), amount)
158    {
159        if (amount == 0) {
160            return;
161        }
162
163        if (token.isNative()) {
164            revert InvalidToken();
165        }
166
167        // allow vaults to burn BNT and VBNT via their respective token governance modules
168        if (token.isEqual(_bnt)) {
169            _bntGovernance.burn(amount);
170        } else if (token.isEqual(_vbnt)) {
171            _vbntGovernance.burn(amount);
172        } else {
173            IERC20Burnable(address(token)).burn(amount);
174        }
175
176        emit FundsBurned({ token: token, caller: msg.sender, amount: amount });
177    }
178
179    /**
180     * @dev returns whether the given caller is allowed access to the given token
181     */
182    function isAuthorizedWithdrawal(
183        address caller,
184        Token token,
185        address target,
186        uint256 amount
187    ) internal view virtual returns (bool);
188
189    /**
190     * @inheritdoc IVault
191     */
192    function isPayable() public view virtual returns (bool);
193
194    /**
195     * @dev authorize the contract to receive the native token
196     *
197     * requirements:
198     *
199     * - isPayable must return true
200     */
201    receive() external payable {
202        if (!isPayable()) {
203            revert NotPayable();
204        }
205    }
206}

JavaScript Tests

Language
Files
Lines
Blanks
Comments
Testing Code
Deployed Code
Complexity
Solidity
19
7986
1258
2010
19305
4718
428

Tests to Code: 19305 / 4718 = 409 %