Harvest Finance PQ Review

Score : 55%

This is a Harvest Finance Process Quality Audit completed on 7 September 2020. It was performed using the Process Audit process (version 0.5) and is documented here. The audit was performed by ShinkaRex of Caliburn Consulting. Check out our Telegram.

The final score of the audit is 55%, a bare pass. The breakdown of the scoring is in Scoring Appendix.

Summary of the Process

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.

  1. Here is my smart contract on the blockchain

  2. You can see it matches a software repository used to develop the code

  3. Here is the documentation that explains what my smart contract does

  4. Here are the tests I ran to verify my smart contract

  5. Here are the audit(s) performed to review my code by third party experts

Disclaimer

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, 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. 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.

Executing Code Verification

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

  1. Is the executing code address(s) readily available? (Y/N)

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

  3. Are the Contract(s) Verified/Verifiable? (Y/N)

  4. Does the code match a tagged version in the code hosting platform? (%)

  5. Is the software repository healthy? (%)

Is the executing code address(s) readily available? (Y/N)

Answer: Yes

They are available at Address 0xe85C8581e60D7Cd32Bbfd86303d2A4FA6a951Dac as indicated in the Appendix. This Audit only covers the contract vault.sol.

The strategies addresses are at https://farm.chainwiki.dev/en/strategy.

Is the code actively being used? (%)

Answer: 100%

Activity is over 100 transactions 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

Are the Contract(s) Verified/Verifiable? (Y/N)

Answer: Yes

0xe85C8581e60D7Cd32Bbfd86303d2A4FA6a951Dac is the Etherscan verified contract address.

Does the code match a tagged version on a code hosting platform? (%)

Answer: 100%

Everything matched cleanly and easily. This github only holds the deployed code so there is only one branch. No labelled release but everything matched so well, a full score is deserved.

Guidance:

100% All code matches and Repository was clearly labelled 60 % All code matches but no labelled repository. Repository was found manually 30% Almost all code does match perfectly and repository was found manually 0% Most matching Code could not be found

GitHub address : https://github.com/harvest-finance

Deployed contracts in the following file;

Matching Repository: https://github.com/harvest-finance/harvest/tree/master/contracts

Is development software repository healthy? (%)

Answer: No

With 8 commits and just one branch, this project was developed in someother place than this repo.

How to improve this score

Ensure there is a clearly labelled repository holding all the contracts, documentation and tests for the deployed code. Continue to test and perform other verification activities after deployment, including routine maintenance updating to new releases of testing and deployment tools.

Documentation

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

Required questions are;

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

  2. Are the basic application requirements documented? (Y/N)

  3. Do the requirements fully (100%) cover the deployed contracts? (%)

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

  5. Is it possible to trace software requirements to the implementation in code (%)

Is there a whitepaper? (Y/N)

Answer: Yes

I will consider his opening medium post as the equivalent of a white paper. It does give the top-level information needed.

Location: https://medium.com/harvest-finance/the-harvest-finance-project-338c3e5806fc

Are the basic application requirements documented? (Y/N)

Answer: Yes

There is a basic flow diagram at : https://farm.chainwiki.dev/en/strategy. Honestly, this is quite light.

How to improve this score

Write the document based on the deployed code. For guidance, refer to the SecurEth System Description Document.

Do the requirements fully (100%) cover the deployed contracts? (%)

Answer: 30%

While some documentation with the flow diagram exists, it is far from documenting the code.

How to improve this score

This score can improve by adding content to the requirements document such that it comprehensively covers the requirements. For guidance, refer to the SecurEth System Description Document . Using tools that aid traceability detection will help.

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

Answer: 70%

Code commenting is very good, with a 46% code to commenting and NatSpec. Much more commenting than normal.

Code examples are in the Appendix. As per the SLOC, there is 46% commenting to code.

How to improve this score

This score can improve by adding comments to the deployed code such that it comprehensively covers the code. For guidance, refer to the SecurEth Software Requirements.

Is it possible to trace requirements to the implementation in code (%)

Answer: 0%

As there was only one flow diagram for requirements, tracing to code was not possible.

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

How to improve this score

This score can improve by adding traceability from requirements to code such that it is clear where each requirement is coded. For reference, check the SecurEth guidelines on traceability.

Testing

This section looks at the software testing available. It is explained in this document. This section answers the following questions;

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

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

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

  4. Packaged with the deployed code (Y/N)

  5. Report of the results (%)

  6. Formal Verification test done (%)

  7. Stress Testing environment (%)

Is there a Full test suite? (%)

Answer: 100%

There is a 149% test to code ratio and a full and varied set of tests

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

Answer: 50%

As is frequently the case, no evidence of test results exists.

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

How to improve this score

This score can improve by adding tests achieving full code coverage. A clear report and scripts in the software repository will guarantee a high score.

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

Answer: Yes

Test instructions are in the truffle config.

Packaged with the deployed code (Y/N)

Answer: Yes

Report of the results (%)

Answer: 0%

No report was visible.

How to improve this score

Add a report with the results. The test scripts should generate the report or elements of it.

Formal Verification test done (%)

Answer: 0%

No evidence of formal validation found.

Stress Testing environment (%)

Answer: 0%

While a ropsten test network did exist during development (as evident from the truffle config)

Audits

Answer: 20%

No audit is complete, as they clearly indicate, though one may be in process.

Guidance:

  1. Multiple Audits performed before deployment and results public and implemented or not required (100%)

  2. Single audit performed before deployment and results public and implemented or not required (90%)

  3. Audit(s) performed after deployment and no changes required. Audit report is public. (70%)

  4. No audit performed (20%)

  5. Audit Performed after deployment, existence is public, report is not public and no improvements deployed OR smart contract address' not found, question 1 (0%)

Appendices

Author Details

The author of this audit is Rex of Caliburn Consulting.

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 Audits are an extension of the SecurEth guidelines that will further increase the quality processes in Solidity and Vyper development.

Career wise I am a business development manager for an avionics supplier.

Scoring Appendix

Executing Code Appendix

Code Used Appendix

Example Code Appendix

contract Vault is ERC20, ERC20Detailed, IVault, Controllable {
using SafeERC20 for IERC20;
using Address for address;
using SafeMath for uint256;
event Withdraw(address indexed beneficiary, uint256 amount);
event Deposit(address indexed beneficiary, uint256 amount);
event Invest(uint256 amount);
IStrategy public strategy;
IERC20 public underlying;
uint256 public underlyingUnit;
mapping(address => uint256) public contributions;
mapping(address => uint256) public withdrawals;
uint256 public vaultFractionToInvestNumerator;
uint256 public vaultFractionToInvestDenominator;
constructor(address _storage,
address _underlying,
uint256 _toInvestNumerator,
uint256 _toInvestDenominator
) ERC20Detailed(
string(abi.encodePacked("FARM_", ERC20Detailed(_underlying).symbol())),
string(abi.encodePacked("f", ERC20Detailed(_underlying).symbol())),
ERC20Detailed(_underlying).decimals()
) Controllable(_storage) public {
underlying = IERC20(_underlying);
require(_toInvestNumerator <= _toInvestDenominator, "cannot invest more than 100%");
require(_toInvestDenominator != 0, "cannot divide by 0");
vaultFractionToInvestDenominator = _toInvestDenominator;
vaultFractionToInvestNumerator = _toInvestNumerator;
underlyingUnit = 10 ** uint256(ERC20Detailed(address(underlying)).decimals());
}
modifier whenStrategyDefined() {
require(address(strategy) != address(0), "Strategy must be defined");
_;
}
// Only smart contracts will be affected by this modifier
modifier defense() {
require(
(msg.sender == tx.origin) || // If it is a normal user and not smart contract,
// then the requirement will pass
!IController(controller()).greyList(msg.sender), // If it is a smart contract, then
"This smart contract has been grey listed" // make sure that it is not on our greyList.
);
_;
}
/**
* Chooses the best strategy and re-invests. If the strategy did not change, it just calls
* doHardWork on the current strategy. Call this through controller to claim hard rewards.
*/
function doHardWork() whenStrategyDefined onlyControllerOrGovernance external {
// ensure that new funds are invested too
invest();
strategy.doHardWork();
}
/*
* Returns the cash balance across all users in this contract.
*/
function underlyingBalanceInVault() view public returns (uint256) {
return underlying.balanceOf(address(this));
}
/* Returns the current underlying (e.g., DAI's) balance together with
* the invested amount (if DAI is invested elsewhere by the strategy).
*/
function underlyingBalanceWithInvestment() view public returns (uint256) {
if (address(strategy) == address(0)) {
// initial state, when not set
return underlyingBalanceInVault();
}
return underlyingBalanceInVault().add(strategy.investedUnderlyingBalance());
}
/*
* Allows for getting the total contributions ever made.
*/
function getContributions(address holder) view public returns (uint256) {
return contributions[holder];
}
/*
* Allows for getting the total withdrawals ever made.
*/
function getWithdrawals(address holder) view public returns (uint256) {
return withdrawals[holder];
}
function getPricePerFullShare() public view returns (uint256) {
return totalSupply() == 0
? underlyingUnit
: underlyingUnit.mul(underlyingBalanceWithInvestment()).div(totalSupply());
}
/* get the user's share (in underlying)
*/
function underlyingBalanceWithInvestmentForHolder(address holder) view external returns (uint256) {
if (totalSupply() == 0) {
return 0;
}
return underlyingBalanceWithInvestment()
.mul(balanceOf(holder))
.div(totalSupply());
}
function setStrategy(address _strategy) public onlyControllerOrGovernance {
require(_strategy != address(0), "new _strategy cannot be empty");
require(IStrategy(_strategy).underlying() == address(underlying), "Vault underlying must match Strategy underlying");
require(IStrategy(_strategy).vault() == address(this), "the strategy does not belong to this vault");
if (address(_strategy) != address(strategy)) {
if (address(strategy) != address(0)) { // if the original strategy (no underscore) is defined
underlying.safeApprove(address(strategy), 0);
strategy.withdrawAllToVault();
}
strategy = IStrategy(_strategy);
underlying.safeApprove(address(strategy), 0);
underlying.safeApprove(address(strategy), uint256(~0));
}
}
function setVaultFractionToInvest(uint256 numerator, uint256 denominator) external onlyGovernance {
require(denominator > 0, "denominator must be greater than 0");
require(numerator < denominator, "denominator must be greater than numerator");
vaultFractionToInvestNumerator = numerator;
vaultFractionToInvestDenominator = denominator;
}
function rebalance() external onlyControllerOrGovernance {
withdrawAll();
invest();
}
function availableToInvestOut() public view returns (uint256) {
uint256 wantInvestInTotal = underlyingBalanceWithInvestment()
.mul(vaultFractionToInvestNumerator)
.div(vaultFractionToInvestDenominator);
uint256 alreadyInvested = strategy.investedUnderlyingBalance();
if (alreadyInvested >= wantInvestInTotal) {
return 0;
} else {
uint256 remainingToInvest = wantInvestInTotal.sub(alreadyInvested);
return remainingToInvest <= underlyingBalanceInVault()
// TODO: we think that the "else" branch of the ternary operation is not
// going to get hit
? remainingToInvest : underlyingBalanceInVault();
}
}

SLOC Appendix

Solidity Contracts

Language

Files

Lines

Blanks

Comments

Code

Complexity

Solidity

35

3720

535

998

2187

240

Comments to Code 998/ 2187 = 46%

Javascript Tests

Language

Files

Lines

Blanks

Comments

Code

Complexity

JavaScript

26

4415

673

487

3255

21

Tests to Code 3255 / 2187 = 149%