ZuckZuckLand NFT

Smart Contract Audit Report

Audit Summary

ZuckZuckLand NFT Audit Report ZuckZuckLand is building two new ERC-20 token contracts in addition to a new NFT project.

For this audit, we reviewed the GEMToken, GKTToken, and GMPBundle contracts provided to us by the project team.

Audit Findings

Please ensure trust in the team prior to investing as they have some control in the ecosystem.
Date: March 15th, 2022.

Finding #1 - ZuckZuckLand - Informational

Description: Several functions are declared public, but are never called internally.
GEMToken.pause, GEMToken.unpause, GEMToken.mintGKTToken.pause, GKTToken.unpause, GKTToken.mint, GMPBundle.initialize, GMPBundle.setStartTime, GMPBundle.setDelay, GMPBundle.setPERIOD, GMPBundle.getAvailableSlot, GMPBundle.preorder, GMPBundle.countOfBundle, GMPBundle.pause, GMPBundle.unpause, GMPBundle.safeMint
Recommendation: We recommend declaring these functions external for additional gas savings on each call.

Contracts Overview

  • As the contracts are implemented with Solidity v0.8.X, they are protected from any underflow/overflow attacks.
GKTToken Contract:
  • This token is intended to serve as a payment token within the GMPBundle contract.
  • The total supply of the $GKT token is 600 million.
  • Initially, 100% of the total supply will be held by the owner.
  • There is a burn function to reduce the total supply; additionally, the circulating supply can be reduced by sending tokens to the 0x..dead address, if desired.
  • Users can burn tokens from other addresses up to the amount of allowance they've been granted.
  • On deployment, the owner is granted the Default Admin role, Minter role, and Pauser role.
  • The Minter role can mint tokens at any time.
  • The Pauser role can pause the burning, minting, and transferring functionality at any time.
  • There are no fees associated with transferring tokens.
  • The contract complies with the ERC20 standard.
GEMToken Contract:
  • This token is intended to serve as a payment token within the GMPBundle contract.
  • Initially, 100% of the total supply will be held by the owner.
  • There is a burn function to reduce the total supply; additionally, the circulating supply can be reduced by sending tokens to the 0x..dead address, if desired.
  • Users can burn tokens from other addresses up to the amount of allowance they've been granted.
  • On deployment, the owner is granted the Default Admin role, Minter role, and Pauser role.
  • The Minter role can mint tokens at any time.
  • The Pauser role can pause the burning, minting, and transferring functionality at any time.
  • There are no fees associated with transferring tokens.
  • The contract complies with the ERC20 standard.
GMPBundle Contract:
  • This contract is used to facilitate a presale and a public sale for the $GMPB NFTs using a team designated token for purchasing.
  • While the whitelist is enabled, eligible users can each purchase up to an owner-defined maximum amount of $GMPB NFTs for a predefined price until the bundle types' maximum total supply has been reached.
  • Once the whitelist is disabled, all users can purchase up to an owner-defined maximum amount of $GMPB NFTs for a predefined price until the bundle types' maximum total supply has been reached.
  • When users open their $GMPB NFTs, the land and mole contract addresses are sent the $GMPB NFT's land and mole properties. The land and mole contracts are not within the scope of this audit, so we are unable to provide an assessment of these contracts with regards to security.
  • Once a $GMPB NFT is opened to claim land and mole NFTs, it is burned.
  • The owner can toggle the whitelist functionality at any time.
  • The owner can withdraw any tokens in the contract to the beneficiary address at any time.
  • The owner can change the payment token at any time.
  • The owner can set the beneficiary, land token, and mole token addresses at any time.
  • The owner can set the APY to any value at any time.
  • The owner can set each $GMPB NFT type's total supply limit and price at any time.
  • The owner can set the start time, period, and delay duration at any time.
  • The owner can pause/unpause the preorder functionality within the contract at any time.
  • The owner can mint any tokens at any time.
  • The contact utilizes logic to prevent against reentrancy.
  • These contracts comply with the ERC-721 standard.

Audit Results

Vulnerability CategoryNotesResult
Arbitrary Jump/Storage WriteN/APASS
Centralization of ControlN/APASS
Compiler IssuesN/APASS
Delegate Call to Untrusted ContractN/APASS
Dependence on Predictable VariablesN/APASS
Ether/Token TheftN/APASS
Flash LoansN/APASS
Front RunningN/APASS
Improper EventsN/APASS
Improper Authorization SchemeN/APASS
Integer Over/UnderflowN/APASS
Logical IssuesN/APASS
Oracle IssuesN/APASS
Outdated Compiler VersionN/APASS
Race ConditionsN/APASS
ReentrancyN/APASS
Signature IssuesN/APASS
Unbounded LoopsN/APASS
Unused CodeN/APASS
Overall Contract Safety PASS

GKTToken Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
  + [Int] IERC20 
    - [Ext] totalSupply
    - [Ext] balanceOf
    - [Ext] transfer #
    - [Ext] allowance
    - [Ext] approve #
    - [Ext] transferFrom #

 + [Int] IERC20Metadata (IERC20)
    - [Ext] name
    - [Ext] symbol
    - [Ext] decimals

 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

 +  ERC20 (Context, IERC20, IERC20Metadata)
    - [Pub]  #
    - [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 #

 +  ERC20Burnable (Context, ERC20)
    - [Pub] burn #
    - [Pub] burnFrom #

 +  Pausable (Context)
    - [Pub]  #
    - [Pub] paused
    - [Int] _pause #
       - modifiers: whenNotPaused
    - [Int] _unpause #
       - modifiers: whenPaused

 + [Int] IAccessControl 
    - [Ext] hasRole
    - [Ext] getRoleAdmin
    - [Ext] grantRole #
    - [Ext] revokeRole #
    - [Ext] renounceRole #

 + [Lib] Strings 
    - [Int] toString
    - [Int] toHexString
    - [Int] toHexString

 + [Int] IERC165 
    - [Ext] supportsInterface

 +  ERC165 (IERC165)
    - [Pub] supportsInterface

 +  AccessControl (Context, IAccessControl, ERC165)
    - [Pub] supportsInterface
    - [Pub] hasRole
    - [Int] _checkRole
    - [Pub] getRoleAdmin
    - [Pub] grantRole #
       - modifiers: onlyRole
    - [Pub] revokeRole #
       - modifiers: onlyRole
    - [Pub] renounceRole #
    - [Int] _setupRole #
    - [Int] _setRoleAdmin #
    - [Int] _grantRole #
    - [Int] _revokeRole #

 +  GKTToken (ERC20, ERC20Burnable, Pausable, AccessControl)
    - [Pub]  #
       - modifiers: ERC20
    - [Pub] pause #
       - modifiers: onlyRole
    - [Pub] unpause #
       - modifiers: onlyRole
    - [Pub] mint #
       - modifiers: onlyRole
    - [Int] _beforeTokenTransfer #
       - modifiers: whenNotPaused


GEMToken Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
  + [Int] IERC20 
    - [Ext] totalSupply
    - [Ext] balanceOf
    - [Ext] transfer #
    - [Ext] allowance
    - [Ext] approve #
    - [Ext] transferFrom #

 + [Int] IERC20Metadata (IERC20)
    - [Ext] name
    - [Ext] symbol
    - [Ext] decimals

 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

 +  ERC20 (Context, IERC20, IERC20Metadata)
    - [Pub]  #
    - [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 #

 +  ERC20Burnable (Context, ERC20)
    - [Pub] burn #
    - [Pub] burnFrom #

 +  Pausable (Context)
    - [Pub]  #
    - [Pub] paused
    - [Int] _pause #
       - modifiers: whenNotPaused
    - [Int] _unpause #
       - modifiers: whenPaused

 + [Int] IAccessControl 
    - [Ext] hasRole
    - [Ext] getRoleAdmin
    - [Ext] grantRole #
    - [Ext] revokeRole #
    - [Ext] renounceRole #

 + [Lib] Strings 
    - [Int] toString
    - [Int] toHexString
    - [Int] toHexString

 + [Int] IERC165 
    - [Ext] supportsInterface

 +  ERC165 (IERC165)
    - [Pub] supportsInterface

 +  AccessControl (Context, IAccessControl, ERC165)
    - [Pub] supportsInterface
    - [Pub] hasRole
    - [Int] _checkRole
    - [Pub] getRoleAdmin
    - [Pub] grantRole #
       - modifiers: onlyRole
    - [Pub] revokeRole #
       - modifiers: onlyRole
    - [Pub] renounceRole #
    - [Int] _setupRole #
    - [Int] _setRoleAdmin #
    - [Int] _grantRole #
    - [Int] _revokeRole #

 +  GEMToken (ERC20, ERC20Burnable, Pausable, AccessControl)
    - [Pub]  #
       - modifiers: ERC20
    - [Pub] pause #
       - modifiers: onlyRole
    - [Pub] unpause #
       - modifiers: onlyRole
    - [Pub] mint #
       - modifiers: onlyRole
    - [Int] _beforeTokenTransfer #
       - modifiers: whenNotPaused

GMPBundle Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
+ [Int] IERC165Upgradeable 
    - [Ext] supportsInterface

 + [Int] IERC721Upgradeable (IERC165Upgradeable)
    - [Ext] balanceOf
    - [Ext] ownerOf
    - [Ext] safeTransferFrom #
    - [Ext] transferFrom #
    - [Ext] approve #
    - [Ext] getApproved
    - [Ext] setApprovalForAll #
    - [Ext] isApprovedForAll
    - [Ext] safeTransferFrom #

 + [Int] IERC721ReceiverUpgradeable 
    - [Ext] onERC721Received #

 + [Int] IERC721MetadataUpgradeable (IERC721Upgradeable)
    - [Ext] name
    - [Ext] symbol
    - [Ext] tokenURI

 + [Lib] AddressUpgradeable 
    - [Int] isContract
    - [Int] sendValue #
    - [Int] functionCall #
    - [Int] functionCall #
    - [Int] functionCallWithValue #
    - [Int] functionCallWithValue #
    - [Int] functionStaticCall
    - [Int] functionStaticCall
    - [Int] verifyCallResult

 +  Initializable 
    - [Prv] _isConstructor

 +  ContextUpgradeable (Initializable)
    - [Int] __Context_init #
       - modifiers: onlyInitializing
    - [Int] __Context_init_unchained #
       - modifiers: onlyInitializing
    - [Int] _msgSender
    - [Int] _msgData

 + [Lib] StringsUpgradeable 
    - [Int] toString
    - [Int] toHexString
    - [Int] toHexString

 +  ERC165Upgradeable (Initializable, IERC165Upgradeable)
    - [Int] __ERC165_init #
       - modifiers: onlyInitializing
    - [Int] __ERC165_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] supportsInterface

 +  ERC721Upgradeable (Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721Upgradeable, IERC721MetadataUpgradeable)
    - [Int] __ERC721_init #
       - modifiers: onlyInitializing
    - [Int] __ERC721_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] supportsInterface
    - [Pub] balanceOf
    - [Pub] ownerOf
    - [Pub] name
    - [Pub] symbol
    - [Pub] tokenURI
    - [Int] _baseURI
    - [Pub] approve #
    - [Pub] getApproved
    - [Pub] setApprovalForAll #
    - [Pub] isApprovedForAll
    - [Pub] transferFrom #
    - [Pub] safeTransferFrom #
    - [Pub] safeTransferFrom #
    - [Int] _safeTransfer #
    - [Int] _exists
    - [Int] _isApprovedOrOwner
    - [Int] _safeMint #
    - [Int] _safeMint #
    - [Int] _mint #
    - [Int] _burn #
    - [Int] _transfer #
    - [Int] _approve #
    - [Int] _setApprovalForAll #
    - [Prv] _checkOnERC721Received #
    - [Int] _beforeTokenTransfer #
    - [Int] _afterTokenTransfer #

 + [Int] IERC721EnumerableUpgradeable (IERC721Upgradeable)
    - [Ext] totalSupply
    - [Ext] tokenOfOwnerByIndex
    - [Ext] tokenByIndex

 +  ERC721EnumerableUpgradeable (Initializable, ERC721Upgradeable, IERC721EnumerableUpgradeable)
    - [Int] __ERC721Enumerable_init #
       - modifiers: onlyInitializing
    - [Int] __ERC721Enumerable_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] supportsInterface
    - [Pub] tokenOfOwnerByIndex
    - [Pub] totalSupply
    - [Pub] tokenByIndex
    - [Int] _beforeTokenTransfer #
    - [Prv] _addTokenToOwnerEnumeration #
    - [Prv] _addTokenToAllTokensEnumeration #
    - [Prv] _removeTokenFromOwnerEnumeration #
    - [Prv] _removeTokenFromAllTokensEnumeration #

 +  ERC721URIStorageUpgradeable (Initializable, ERC721Upgradeable)
    - [Int] __ERC721URIStorage_init #
       - modifiers: onlyInitializing
    - [Int] __ERC721URIStorage_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] tokenURI
    - [Int] _setTokenURI #
    - [Int] _burn #

 +  PausableUpgradeable (Initializable, ContextUpgradeable)
    - [Int] __Pausable_init #
       - modifiers: onlyInitializing
    - [Int] __Pausable_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] paused
    - [Int] _pause #
       - modifiers: whenNotPaused
    - [Int] _unpause #
       - modifiers: whenPaused

 +  OwnableUpgradeable (Initializable, ContextUpgradeable)
    - [Int] __Ownable_init #
       - modifiers: onlyInitializing
    - [Int] __Ownable_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] owner
    - [Pub] renounceOwnership #
       - modifiers: onlyOwner
    - [Pub] transferOwnership #
       - modifiers: onlyOwner
    - [Int] _transferOwnership #

 + [Lib] CountersUpgradeable 
    - [Int] current
    - [Int] increment #
    - [Int] decrement #
    - [Int] reset #

 + [Int] IERC20 
    - [Ext] totalSupply
    - [Ext] balanceOf
    - [Ext] transfer #
    - [Ext] allowance
    - [Ext] approve #
    - [Ext] transferFrom #

 + [Int] IERC20Metadata (IERC20)
    - [Ext] name
    - [Ext] symbol
    - [Ext] decimals

 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

 +  ERC20 (Context, IERC20, IERC20Metadata)
    - [Pub]  #
    - [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 #

 +  ERC20Burnable (Context, ERC20)
    - [Pub] burn #
    - [Pub] burnFrom #

 + [Lib] SafeMath 
    - [Int] tryAdd
    - [Int] trySub
    - [Int] tryMul
    - [Int] tryDiv
    - [Int] tryMod
    - [Int] add
    - [Int] sub
    - [Int] mul
    - [Int] div
    - [Int] mod
    - [Int] sub
    - [Int] div
    - [Int] mod

 +  ERC721BurnableUpgradeable (Initializable, ContextUpgradeable, ERC721Upgradeable)
    - [Int] __ERC721Burnable_init #
       - modifiers: onlyInitializing
    - [Int] __ERC721Burnable_init_unchained #
       - modifiers: onlyInitializing
    - [Pub] burn #

 +  LandNFT (Initializable, ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable, PausableUpgradeable, OwnableUpgradeable, ERC721BurnableUpgradeable)
    - [Pub]  #
       - modifiers: initializer
    - [Pub] initialize #
       - modifiers: initializer
    - [Pub] isWhitelisted
    - [Ext] setOnlyWhitelisted #
       - modifiers: onlyOwner
    - [Ext] setAllowPublicMint #
       - modifiers: onlyOwner
    - [Ext] setLandPrice #
       - modifiers: onlyOwner
    - [Ext] mint #
    - [Ext] openBundles #
    - [Pub] setToken #
       - modifiers: onlyOwner
    - [Pub] setbundleAddress #
       - modifiers: onlyOwner
    - [Int] _isContract
    - [Int] _baseURI
    - [Pub] pause #
       - modifiers: onlyOwner
    - [Pub] unpause #
       - modifiers: onlyOwner
    - [Pub] safeMint #
       - modifiers: onlyOwner
    - [Int] _beforeTokenTransfer #
       - modifiers: whenNotPaused
    - [Int] _burn #
    - [Pub] tokenURI
    - [Pub] supportsInterface

 +  MoleNFT (Initializable, ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable, PausableUpgradeable, OwnableUpgradeable, ERC721BurnableUpgradeable)
    - [Pub]  #
       - modifiers: initializer
    - [Pub] initialize #
       - modifiers: initializer
    - [Pub] isWhitelisted
    - [Ext] setOnlyWhitelisted #
       - modifiers: onlyOwner
    - [Ext] setAllowPublicMint #
       - modifiers: onlyOwner
    - [Ext] setMolePrice #
       - modifiers: onlyOwner
    - [Ext] mint #
    - [Ext] openBundles #
    - [Pub] setToken #
       - modifiers: onlyOwner
    - [Int] _isContract
    - [Int] _baseURI
    - [Pub] pause #
       - modifiers: onlyOwner
    - [Pub] unpause #
       - modifiers: onlyOwner
    - [Pub] safeMint #
       - modifiers: onlyOwner
    - [Int] _beforeTokenTransfer #
       - modifiers: whenNotPaused
    - [Int] _burn #
    - [Pub] tokenURI
    - [Pub] supportsInterface

 +  GMPBundle (Initializable, ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable, PausableUpgradeable, OwnableUpgradeable)
    - [Pub]  #
       - modifiers: initializer
    - [Pub] initialize #
       - modifiers: initializer
    - [Pub] isWhitelisted
    - [Ext] setOnlyWhitelisted #
       - modifiers: onlyOwner
    - [Ext] setERC20Token #
       - modifiers: onlyOwner
    - [Ext] setLandToken #
       - modifiers: onlyOwner
    - [Ext] setMoleToken #
       - modifiers: onlyOwner
    - [Ext] setAPY #
       - modifiers: onlyOwner
    - [Ext] setNFTLimit #
       - modifiers: onlyOwner
    - [Ext] setNFTPrice #
       - modifiers: onlyOwner
    - [Ext] setBeneficiary #
       - modifiers: onlyOwner
    - [Pub] setStartTime #
       - modifiers: onlyOwner
    - [Pub] setDelay #
       - modifiers: onlyOwner
    - [Pub] setPERIOD #
       - modifiers: onlyOwner
    - [Pub] getMyNFTs
    - [Ext] getNFTsbyAddress
    - [Prv] burn #
    - [Ext] openBundles #
    - [Ext] setBurnAfterOpen #
       - modifiers: onlyOwner
    - [Int] _isContract
    - [Ext] ClaimToken #
       - modifiers: onlyOwner
    - [Pub] getAvailableSlot
    - [Pub] preorder #
       - modifiers: whenNotPaused,notContract
    - [Pub] countOfBundle
    - [Pub] pause #
       - modifiers: onlyOwner
    - [Pub] unpause #
       - modifiers: onlyOwner
    - [Pub] safeMint #
       - modifiers: onlyOwner
    - [Int] _beforeTokenTransfer #
       - modifiers: whenNotPaused
    - [Int] _burn #
    - [Pub] tokenURI
    - [Pub] supportsInterface

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What is a Solidity Audit?

Typically, a smart contract audit is a comprehensive review process designed to discover logical errors, security vulnerabilities, and optimization opportunities within code. A Solidity 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.