Frank Inu

Smart Contract Audit Report

Audit Summary

Frank Inu Audit Report Frank Inu is building a new marketplace for selling tokens and NFTs.

For this audit, we reviewed the project team's NFTSwap contract at commit 69b3b5b095906b43f128d06e1c03f58ea966ac8b on the team's GitHub repository.

Audit Findings

Please ensure trust in the team prior to investing as they have some control in the ecosystem.
Date: April 13th, 2022.

Finding #1 - NFTSwap - High

Description: There does not exist a function to withdraw funds from the contract.
Risk/Impact: Funds collected as fees will be stuck in the contract.
Recommendation: The team should implement a function that allows the owner to withdraw funds from the contract.
Resolution: The team has not yet addressed this issue.

Finding #2 - NFTSwap - Informational

Description: The contract is implemented using Solidity v0.8.0 which is protected against overflow/underflow errors.
Recommendation: The SafeMath library can be removed for additional gas savings.

Contract Overview

  • This contract implements a marketplace for listing and buying NFTs and ERC20 tokens.
  • Users can list any amount of NFTs or tokens for any price at any time.
  • Listings have an associated expiry date that is provided at the time of listing.
  • Users can remove their listing at any time before the expiry date.
  • Users can buy active listings of tokens or NFTs for their listed price at any time.
  • A fee is taken on every sale and stored in the contract.
  • NFTs and tokens listed are kept by the lister until a buyer pays for them.
  • When a user buys an NFT or token, the contract transfers it from the seller to the buyer.
  • The contract must be given the allowance to transfer the listed NFT or tokens in order to sell them.
  • In the event that the address receiving an NFT is a contract, the contract must have implemented the onERC721Received() or onERC1155Received() function in order to successfully receive the NFT.
  • The Owner can set the fee amount to any value up to 99.99%.

  • The contract utilizes reentrancy protection to prevent against reentrancy attacks in applicable functions.
  • As the contract is implemented with Solidity v0.8.0, it is safe from any possible overflows/underflows.

Audit Results

Vulnerability CategoryNotesResult
Arbitrary Jump/Storage WriteN/APASS
Centralization of ControlThe Owner can set the fee amount to any value up to 99.99%.WARNING
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
Signature IssuesN/APASS
Unbounded LoopsN/APASS
Unused CodeN/APASS
Overall Contract Safety PASS

Inheritance Chart

Smart Contract Audit - Inheritance

Function Graph

Smart Contract Audit - Graph

Functions Overview

 ($) = payable function
 # = non-constant function
 Int = Internal
 Ext = External
 Pub = Public

 + [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

 + [Int] IPropertyValidator 
    - [Ext] validateProperty

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

 + [Lib] Orders 
    - [Int] getTokenHash
    - [Int] getNFTListingHash
    - [Int] getTokenListingHash

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

 +  Ownable (Context)
    - [Pub]  #
    - [Pub] owner
    - [Pub] renounceOwnership #
       - modifiers: onlyOwner
    - [Pub] transferOwnership #
       - modifiers: onlyOwner
    - [Int] _transferOwnership #

 + [Int] IERC721 
    - [Ext] safeTransferFrom #
    - [Ext] safeTransferFrom #
    - [Ext] approve #
    - [Ext] setApprovalForAll #
    - [Ext] balanceOf
    - [Ext] transferFrom #
    - [Ext] ownerOf
    - [Ext] getApproved
    - [Ext] isApprovedForAll

 + [Int] IERC1155 
    - [Ext] safeTransferFrom #
    - [Ext] safeBatchTransferFrom #
    - [Ext] setApprovalForAll #
    - [Ext] isApprovedForAll
    - [Ext] balanceOf
    - [Ext] balanceOfBatch

 +  NFTSwap (Ownable)
    - [Pub]  #
    - [Ext]  ($)
    - [Ext]  ($)
    - [Ext] getFee
    - [Ext] calculateNFTListingHash
    - [Ext] calculateTokenListingHash
    - [Ext] getAllTokenListings
    - [Ext] getNFTListing
    - [Ext] getTokenListing
    - [Prv] _takeFee
    - [Ext] createNFTSellOrder #
    - [Ext] cancelNFTSellOrder #
    - [Ext] cancelOTCSellOrder #
    - [Ext] createOTCSellOrder #
    - [Ext] setFee #
       - modifiers: onlyOwner
    - [Prv] _createOTCSellOrder #
    - [Ext] submitOTCBuyOrder ($)
       - modifiers: exchangeInProgress
    - [Prv] _submitOTCBuyOrder #
    - [Ext] submitNFTBuyOrder ($)
       - modifiers: exchangeInProgress
    - [Prv] _createNFTSellOrder #
    - [Prv] _submitNFTBuyOrder #
    - [Prv] _buy20 #
    - [Prv] _buy721 #
    - [Prv] _buy1155 #

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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.