Factor
Smart Contract Audit Report
Audit Summary
Factor is building a new staking and investing platform with governance.
For this audit, we reviewed the following contracts on the team's private GitHub repositories:
- Factor and BasketVault contracts at commit 2b5e5cb360077d31c86f0394fc4e536eafb23e20.
- VotingEscrow and Blocklist contracts at commit 921dc6967e2def2b885232b27ef3484c041d46e9.
Audit Findings
All findings have been resolved, though some centralized aspects are present.
Date: February 15th, 2023.
Updated: February 16th, 2023 to reflect changes to the Factor and BasketVault contracts from commit 921dc6967e2def2b885232b27ef3484c041d46e9 to commit 2b5e5cb360077d31c86f0394fc4e536eafb23e20.Finding #1 - BasketVault - Medium (Resolved)
Description: While a small number of BasketVault shares exist, the share price can be inflated to an extremely large value through a "donation" of a Basket token. If the share price is inflated to a large enough amount, users will not receive any shares for a donation.
Risk/Impact: Deposits can be stolen through frontrunning when a low number of BasketVault shares exist through the use of a donation.
Example Scenario:Recommendation: A precision multiplier should be added to the initial number of minted shares to ensure a low share price, or the team can make a non-trivial deposit once the contract is deployed to prevent any share price manipulation.
- Alice deposits 1 wei of the asset token for 1 wei of a share, the total supply is now 1 wei.
- Alice donates 100,000 of any Basket Token, with a 1:1 Basket Token to Asset Token example conversion rate for simplicity.
- Bob then deposits 1,000 asset tokens, expecting to receive 1000 shares.
- Bob's shares to be minted are calculated as (1000e18 * 1) / 100,000e18, which is rounded down to 0. Alice can then withdraw Bob's funds as she still holds the share supply.
Resolution: The Vault must now be "started" by the Admin before users can deposit, which involves a deposit into the Vault in exchange for shares. The team should ensure that the deposit amount is significant.
Finding #2 - BasketVault - Medium (Resolved)
Description: In the _getPrice() function, the following line containing division before multiplication may return inaccurate values due to truncation.
Risk/Impact: Users may receive a different number of shares or assets than intended due to truncated price values.uint256 priceUSDC = (uint256(basePrice) / uint256(quotePrice)) * 10 ** assetTokenDecimals;
Recommendation: The team should update the mentioned line to the following:
Resolution: The team has implemented the above recommendation.uint256 priceUSDC = uint256(basePrice) * (10 ** assetTokenDecimals) / uint256(quotePrice);
Contracts Overview
Factor Contract:
- ReentrancyGuard is utilized to prevent against reentrancy attacks in applicable functions.
- As the contracts are implemented with Solidity v0.8.x, they are safe from any possible overflows/underflows.
- The team must exercise caution and avoid using a fee-on-transfer token as the staking token or as a Basket token the BasketVault contract.
- The team must exercise caution when assigning the VotingEscrow staking token to avoid using a fee-on-transfer token or a token with less than 6 decimals.
VotingEscrow Contract:
- The initializer is minted 100 million Factor tokens upon initialization.
- No further minting functionality is present.
- Users can burn their tokens at any time to decrease the total supply.
- Each Factor token additionally represents votes intended to be used in a DAO where one token represents one vote.
- Users may delegate their votes to another address allowing them to vote on behalf of the user.
- Once votes are delegated, the user must explicitly delegate back to themselves to regain their votes.
- Users also have the option to delegate through the use of a signed message, allowing for a gasless delegation for the user.
- This contract complies with the ERC20 Upgradeable standard.
Blocklist Contract:
- A user's VotingEscrow balance is used to represent voting weight in a DAO system.
- Users receive a VotingEscrow balance by locking specified tokens in the contract.
- Users' voting power is weighted where the longer tokens are locked the greater the voting power.
- The maximum amount of time tokens can be locked is 4 years.
- After tokens have been locked, their voting power will decrease over time.
- Users' votes are stored once per checkpoint.
- Users may deposit additional tokens into an existing lock or extend the unlock time of an existing lock.
- Users may delegate their lock and voting power to a lock with a longer duration if desired.
- Once delegated, the lock's expiration is updated to the delegatee lock's expiration time.
- Users may withdraw tokens from an expired lock as long as their lock has been "undelegated".
- If withdrawing before a lock is expired, the user must pay a penalty, which is stored in the contract for the Penalty Recipient address.
- The penalty amount decreases linearly over the course of the span of the lock.
- Any address can withdraw accumulated penalties to the Penalty Recipient at any time.
- A contract cannot create, extend, delagate, or contribute to a lock if it has been blocked using the associated Blocklist contract.
- The Blocklist contract can remove delegation from any address at any time.
- The owner can permanently remove the unlock penalty at any time.
- The owner can update the penalty fee recipient address at any time.
- The owner can update the Blocklist contract at any time.
- Ownership can be transferred at any time.
- The team should not set the staking token as a fee-on-transfer token or a token with less than 6 decimals.
BasketVault Contract:
- This contract allows a Manager to block specific contracts from interacting with the VotingEscrow contract.
- The Manager and VotingEscrow addresses are set upon deployment and cannot be updated.
- The Manager can add a contract to the Block List at any time. This will also undelegate the specified contract address.
- Once blocked, a contract cannot be unblocked.
- This contract allows users to deposit any amount of the contract's specified asset token in exchange for minted BasketVault shares.
- Upon deposit, the amount is divided and swapped for tokens corresponding to each "Basket".
- The amount swapped for each Basket token is determined by the Basket's ratio.
- A 1% slippage is permitted in relation to the expected amount.
- The number of shares minted to the user is determined by the user's deposit amount in proportion to the total asset token value held by the contract.
- Each Basket's value is determined using its assigned "Base" and "Quote" Chainlink Oracles. These values are summed to determine the total asset token value.
- Users can alternatively input a desired share amount to mint, where the required deposit amount is calculated.
- Users can redeem their BasketVault shares at any time, or redeem other users' tokens if they have been granted an allowance.
- This swaps amounts of each Basket token back to the original asset token based on the user's redemption amount.
- BasketVault shares are burned from the user they are redeemed from.
- The deployer is granted the Manager and Admin Roles upon deployment.
- The Manager can pause the contract at any time.
- Deposits, withdrawals, redemptions, mints and BasketVault share transfers are all disabled while the contract is paused.
- This contract is intended to be used behind an upgradeable proxy.
Audit Results
| Vulnerability Category | Notes | Result |
|---|---|---|
| Arbitrary Jump/Storage Write | N/A | PASS |
| Centralization of Control |
|
WARNING |
| Compiler Issues | N/A | PASS |
| Delegate Call to Untrusted Contract | N/A | PASS |
| Dependence on Predictable Variables | N/A | PASS |
| Ether/Token Theft | N/A | PASS |
| Flash Loans | N/A | PASS |
| Front Running | N/A | PASS |
| Improper Events | N/A | PASS |
| Improper Authorization Scheme | N/A | PASS |
| Integer Over/Underflow | N/A | PASS |
| Logical Issues | N/A | PASS |
| Oracle Issues | N/A | PASS |
| Outdated Compiler Version | N/A | PASS |
| Race Conditions | N/A | PASS |
| Reentrancy | N/A | PASS |
| Signature Issues | N/A | PASS |
| Sybil Attack | N/A | PASS |
| Unbounded Loops | N/A | PASS |
| Unused Code | N/A | PASS |
| Overall Contract Safety | PASS |
Factor Contract
($) = payable function
# = non-constant function
Int = Internal
Ext = External
Pub = Public
+ [Int] IERC20Upgradeable
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] transfer #
- [Ext] allowance
- [Ext] approve #
- [Ext] transferFrom #
+ [Int] IERC20MetadataUpgradeable (IERC20Upgradeable)
- [Ext] name
- [Ext] symbol
- [Ext] decimals
+ [Lib] AddressUpgradeable
- [Int] isContract
- [Int] sendValue #
- [Int] functionCall #
- [Int] functionCall #
- [Int] functionCallWithValue #
- [Int] functionCallWithValue #
- [Int] functionStaticCall
- [Int] functionStaticCall
- [Int] verifyCallResultFromTarget
- [Int] verifyCallResult
- [Prv] _revert
+ Initializable
- [Int] _disableInitializers #
- [Int] _getInitializedVersion
- [Int] _isInitializing
+ ContextUpgradeable (Initializable)
- [Int] __Context_init #
- modifiers: onlyInitializing
- [Int] __Context_init_unchained #
- modifiers: onlyInitializing
- [Int] _msgSender
- [Int] _msgData
+ ERC20Upgradeable (Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable)
- [Int] __ERC20_init #
- modifiers: onlyInitializing
- [Int] __ERC20_init_unchained #
- modifiers: onlyInitializing
- [Pub] name
- [Pub] symbol
- [Pub] decimals
- [Pub] totalSupply
- [Pub] balanceOf
- [Pub] transfer #
- [Pub] allowance
- [Pub] approve #
- [Pub] transferFrom #
- [Pub] increaseAllowance #
- [Pub] decreaseAllowance #
- [Int] _transfer #
- [Int] _mint #
- [Int] _burn #
- [Int] _approve #
- [Int] _spendAllowance #
- [Int] _beforeTokenTransfer #
- [Int] _afterTokenTransfer #
+ ERC20BurnableUpgradeable (Initializable, ContextUpgradeable, ERC20Upgradeable)
- [Int] __ERC20Burnable_init #
- modifiers: onlyInitializing
- [Int] __ERC20Burnable_init_unchained #
- modifiers: onlyInitializing
- [Pub] burn #
- [Pub] burnFrom #
+ Factor (Initializable, ERC20Upgradeable, ERC20BurnableUpgradeable)
- [Pub] #
- [Pub] initialize #
- modifiers: initializer
VotingEscrow Contract
($) = payable function
# = non-constant function
Int = Internal
Ext = External
Pub = Public
+ ReentrancyGuard
- [Pub] #
- [Prv] _nonReentrantBefore #
- [Prv] _nonReentrantAfter #
+ [Int] IERC20
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] transfer #
- [Ext] allowance
- [Ext] approve #
- [Ext] transferFrom #
+ [Int] IERC20Permit
- [Ext] permit #
- [Ext] nonces
- [Ext] DOMAIN_SEPARATOR
+ [Lib] Address
- [Int] isContract
- [Int] sendValue #
- [Int] functionCall #
- [Int] functionCall #
- [Int] functionCallWithValue #
- [Int] functionCallWithValue #
- [Int] functionStaticCall
- [Int] functionStaticCall
- [Int] functionDelegateCall #
- [Int] functionDelegateCall #
- [Int] verifyCallResultFromTarget
- [Int] verifyCallResult
- [Prv] _revert
+ [Lib] SafeERC20
- [Int] safeTransfer #
- [Int] safeTransferFrom #
- [Int] safeApprove #
- [Int] safeIncreaseAllowance #
- [Int] safeDecreaseAllowance #
- [Int] safePermit #
- [Prv] _callOptionalReturn #
+ [Int] IERC20Metadata (IERC20)
- [Ext] name
- [Ext] symbol
- [Ext] decimals
+ [Int] IVotingEscrow
- [Ext] createLock #
- [Ext] increaseAmount #
- [Ext] increaseUnlockTime #
- [Ext] withdraw #
- [Ext] delegate #
- [Ext] quitLock #
- [Ext] balanceOf
- [Ext] balanceOfAt
- [Ext] totalSupply
- [Ext] totalSupplyAt
- [Ext] forceUndelegate #
+ [Int] IBlocklist
- [Ext] isBlocked
+ [Int] IVotes
- [Ext] getVotes
- [Ext] getPastVotes
- [Ext] getPastTotalSupply
- [Ext] delegates
- [Ext] delegate #
- [Ext] delegateBySig #
+ VotingEscrow (IVotingEscrow, IVotes, ReentrancyGuard)
- [Pub] #
- [Ext] transferOwnership #
- modifiers: onlyOwner
- [Ext] updateBlocklist #
- modifiers: onlyOwner
- [Ext] updatePenaltyRecipient #
- modifiers: onlyOwner
- [Ext] unlock #
- modifiers: onlyOwner
- [Ext] forceUndelegate #
- [Ext] lockEnd
- [Ext] getLastUserPoint
- [Int] _checkpoint #
- [Ext] checkpoint #
- [Ext] createLock #
- modifiers: nonReentrant,checkBlocklist
- [Ext] increaseAmount #
- modifiers: nonReentrant,checkBlocklist
- [Ext] increaseUnlockTime #
- modifiers: nonReentrant,checkBlocklist
- [Ext] withdraw #
- modifiers: nonReentrant
- [Ext] delegate #
- modifiers: nonReentrant,checkBlocklist
- [Int] _undelegate #
- [Int] _delegate #
- [Ext] quitLock #
- modifiers: nonReentrant
- [Ext] getPenaltyRate
- [Int] _calculatePenaltyRate
- [Ext] collectPenalty #
- [Int] _copyLock
- [Int] _floorToWeek
- [Int] _findBlockEpoch
- [Int] _findUserBlockEpoch
- [Pub] balanceOf
- [Pub] balanceOfAt
- [Int] _supplyAt
- [Pub] totalSupply
- [Pub] totalSupplyAt
- [Ext] getVotes
- [Ext] getPastVotes
- [Ext] getPastTotalSupply
- [Ext] delegates
- [Ext] delegateBySig
Blocklist Contract
($) = payable function
# = non-constant function
Int = Internal
Ext = External
Pub = Public
+ [Int] IVotingEscrow
- [Ext] createLock #
- [Ext] increaseAmount #
- [Ext] increaseUnlockTime #
- [Ext] withdraw #
- [Ext] delegate #
- [Ext] quitLock #
- [Ext] balanceOf
- [Ext] balanceOfAt
- [Ext] totalSupply
- [Ext] totalSupplyAt
- [Ext] forceUndelegate #
+ Blocklist
- [Pub] #
- [Ext] blockContract #
- [Ext] isBlocked
BasketVault Contract
($) = payable function
# = non-constant function
Int = Internal
Ext = External
Pub = Public
+ [Int] IERC20Upgradeable
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] transfer #
- [Ext] allowance
- [Ext] approve #
- [Ext] transferFrom #
+ [Int] IERC20MetadataUpgradeable (IERC20Upgradeable)
- [Ext] name
- [Ext] symbol
- [Ext] decimals
+ [Lib] AddressUpgradeable
- [Int] isContract
- [Int] sendValue #
- [Int] functionCall #
- [Int] functionCall #
- [Int] functionCallWithValue #
- [Int] functionCallWithValue #
- [Int] functionStaticCall
- [Int] functionStaticCall
- [Int] verifyCallResultFromTarget
- [Int] verifyCallResult
- [Prv] _revert
+ Initializable
- [Int] _disableInitializers #
- [Int] _getInitializedVersion
- [Int] _isInitializing
+ ContextUpgradeable (Initializable)
- [Int] __Context_init #
- modifiers: onlyInitializing
- [Int] __Context_init_unchained #
- modifiers: onlyInitializing
- [Int] _msgSender
- [Int] _msgData
+ ERC20Upgradeable (Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable)
- [Int] __ERC20_init #
- modifiers: onlyInitializing
- [Int] __ERC20_init_unchained #
- modifiers: onlyInitializing
- [Pub] name
- [Pub] symbol
- [Pub] decimals
- [Pub] totalSupply
- [Pub] balanceOf
- [Pub] transfer #
- [Pub] allowance
- [Pub] approve #
- [Pub] transferFrom #
- [Pub] increaseAllowance #
- [Pub] decreaseAllowance #
- [Int] _transfer #
- [Int] _mint #
- [Int] _burn #
- [Int] _approve #
- [Int] _spendAllowance #
- [Int] _beforeTokenTransfer #
- [Int] _afterTokenTransfer #
+ [Int] IERC4626Upgradeable (IERC20Upgradeable, IERC20MetadataUpgradeable)
- [Ext] asset
- [Ext] totalAssets
- [Ext] convertToShares
- [Ext] convertToAssets
- [Ext] maxDeposit
- [Ext] previewDeposit
- [Ext] deposit #
- [Ext] maxMint
- [Ext] previewMint
- [Ext] mint #
- [Ext] maxWithdraw
- [Ext] previewWithdraw
- [Ext] withdraw #
- [Ext] maxRedeem
- [Ext] previewRedeem
- [Ext] redeem #
+ ERC20BurnableUpgradeable (Initializable, ContextUpgradeable, ERC20Upgradeable)
- [Int] __ERC20Burnable_init #
- modifiers: onlyInitializing
- [Int] __ERC20Burnable_init_unchained #
- modifiers: onlyInitializing
- [Pub] burn #
- [Pub] burnFrom #
+ PausableUpgradeable (Initializable, ContextUpgradeable)
- [Int] __Pausable_init #
- modifiers: onlyInitializing
- [Int] __Pausable_init_unchained #
- modifiers: onlyInitializing
- [Pub] paused
- [Int] _requireNotPaused
- [Int] _requirePaused
- [Int] _pause #
- modifiers: whenNotPaused
- [Int] _unpause #
- modifiers: whenPaused
+ [Int] IAccessControlUpgradeable
- [Ext] hasRole
- [Ext] getRoleAdmin
- [Ext] grantRole #
- [Ext] revokeRole #
- [Ext] renounceRole #
+ [Lib] MathUpgradeable
- [Int] max
- [Int] min
- [Int] average
- [Int] ceilDiv
- [Int] mulDiv
- [Int] mulDiv
- [Int] sqrt
- [Int] sqrt
- [Int] log2
- [Int] log2
- [Int] log10
- [Int] log10
- [Int] log256
- [Int] log256
+ [Lib] StringsUpgradeable
- [Int] toString
- [Int] toHexString
- [Int] toHexString
- [Int] toHexString
+ [Int] IERC165Upgradeable
- [Ext] supportsInterface
+ ERC165Upgradeable (Initializable, IERC165Upgradeable)
- [Int] __ERC165_init #
- modifiers: onlyInitializing
- [Int] __ERC165_init_unchained #
- modifiers: onlyInitializing
- [Pub] supportsInterface
+ AccessControlUpgradeable (Initializable, ContextUpgradeable, IAccessControlUpgradeable, ERC165Upgradeable)
- [Int] __AccessControl_init #
- modifiers: onlyInitializing
- [Int] __AccessControl_init_unchained #
- modifiers: onlyInitializing
- [Pub] supportsInterface
- [Pub] hasRole
- [Int] _checkRole
- [Int] _checkRole
- [Pub] getRoleAdmin
- [Pub] grantRole #
- modifiers: onlyRole
- [Pub] revokeRole #
- modifiers: onlyRole
- [Pub] renounceRole #
- [Int] _setupRole #
- [Int] _setRoleAdmin #
- [Int] _grantRole #
- [Int] _revokeRole #
+ ReentrancyGuardUpgradeable (Initializable)
- [Int] __ReentrancyGuard_init #
- modifiers: onlyInitializing
- [Int] __ReentrancyGuard_init_unchained #
- modifiers: onlyInitializing
- [Prv] _nonReentrantBefore #
- [Prv] _nonReentrantAfter #
+ [Int] IERC20
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] transfer #
- [Ext] allowance
- [Ext] approve #
- [Ext] transferFrom #
+ [Int] IERC20Decimals
- [Ext] decimals
+ [Int] IERC20Permit
- [Ext] permit #
- [Ext] nonces
- [Ext] DOMAIN_SEPARATOR
+ [Lib] Address
- [Int] isContract
- [Int] sendValue #
- [Int] functionCall #
- [Int] functionCall #
- [Int] functionCallWithValue #
- [Int] functionCallWithValue #
- [Int] functionStaticCall
- [Int] functionStaticCall
- [Int] functionDelegateCall #
- [Int] functionDelegateCall #
- [Int] verifyCallResultFromTarget
- [Int] verifyCallResult
- [Prv] _revert
+ [Lib] SafeERC20
- [Int] safeTransfer #
- [Int] safeTransferFrom #
- [Int] safeApprove #
- [Int] safeIncreaseAllowance #
- [Int] safeDecreaseAllowance #
- [Int] safePermit #
- [Prv] _callOptionalReturn #
+ [Int] IChainlinkAggregatorV3
- [Ext] latestRoundData
- [Ext] decimals
+ [Int] IUniswapV3SwapCallback
- [Ext] uniswapV3SwapCallback #
+ [Int] ISwapRouter (IUniswapV3SwapCallback)
- [Ext] exactInputSingle ($)
- [Ext] exactInput ($)
- [Ext] exactOutputSingle ($)
- [Ext] exactOutput ($)
+ [Lib] TransferHelper
- [Int] safeTransferFrom #
- [Int] safeTransfer #
- [Int] safeApprove #
- [Int] safeTransferETH #
+ BasketVault (Initializable, ERC20Upgradeable, ERC20BurnableUpgradeable, IERC4626Upgradeable, ReentrancyGuardUpgradeable, PausableUpgradeable, AccessControlUpgradeable)
- [Pub] #
- [Pub] initialize #
- modifiers: initializer
- [Pub] pause #
- modifiers: onlyRole
- [Pub] unpause #
- modifiers: onlyRole
- [Int] _beforeTokenTransfer #
- modifiers: whenNotPaused
- [Ext] asset
- [Pub] totalAssets
- [Ext] convertToShares
- [Ext] deposit #
- modifiers: nonReentrant,whenNotPaused
- [Ext] mint #
- modifiers: nonReentrant,whenNotPaused
- [Int] _deposit #
- [Ext] maxDeposit
- [Pub] maxMint
- [Ext] previewDeposit
- [Ext] previewMint
- [Ext] withdraw #
- modifiers: nonReentrant,whenNotPaused
- [Ext] redeem #
- modifiers: nonReentrant,whenNotPaused
- [Int] _withdraw #
- [Pub] maxWithdraw
- [Pub] maxRedeem
- [Ext] previewWithdraw
- [Ext] previewRedeem
- [Ext] convertToAssets
- [Pub] _convertToShares
- [Pub] _convertToAssets
- [Int] _swap #
- [Pub] _getPrice
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Typically, a smart contract audit is a comprehensive review process designed to discover logical errors, security vulnerabilities, and optimization opportunities within code. A SourceHat Audit takes this a step further by verifying economic logic to ensure the stability of smart contracts and highlighting privileged functionality to create a report that is easy to understand for developers and community members alike.
How Do I Interpret the Findings?
Each of our Findings will be labeled with a Severity level. We always recommend the team resolve High, Medium, and Low severity findings prior to deploying the code to the mainnet. Here is a breakdown on what each Severity level means for the project:
- High severity indicates that the issue puts a large number of users' funds at risk and has a high probability of exploitation, or the smart contract contains serious logical issues which can prevent the code from operating as intended.
- Medium severity issues are those which place at least some users' funds at risk and has a medium to high probability of exploitation.
- Low severity issues have a relatively minor risk association; these issues have a low probability of occurring or may have a minimal impact.
- Informational issues pose no immediate risk, but inform the project team of opportunities for gas optimizations and following smart contract security best practices.