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# Brain Station 23 Ltd.

This report was made by

| Name | Brain Station 23 ID | Official Email | Auditor Type |
| --- | --- | --- | --- |
| [Sampad Sikder](https://www.linkedin.com/in/sampad-sikder-897b90200/) | BS1464 |[e-mail] | External |
| [Mashiat Amin Farin](https://www.linkedin.com/in/mashiataminfarin/)| BS1463 | [e-mail] | External|
| [Md. Ariful Islam](https://www.linkedin.com/in/engr-arif/) | BS1121 | [e-mail] | Internal |

### Tools used
- Solidity Metrics (IDE Extenstion)
- Slither
- Aderyn
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### Standards used
- Rekt test
- Tincho Method
- [cyfrin.io standard](https://www.cyfrin.io/)

# Hotelereum NFT Market Audit Report

## Private Audit
A NFT Marketplace for Hotel Rooms and Holiday packages. Hotel partners can enlist their inventory price in stable coins. Users can purchase NFTs (Bookings) in MATIC coin or stable coin.

## Developer report
In progress
- how to setup project
npm install --force
install and run hardhat

- Commit Hash
e12d3e29ce9ae74774110d47b53d7e426ef08e64

- Repo URL: (https://github.com/nsal-ai/Blockchain-Web3/tree/develop)
Branch:Develop

- In scope vs out of scope contracts
./contract/
└── Hotelereum-NFT-Marketplace.sol

- Compatibilities
Solc Version: 0.8.19
Chain(s) to deploy contract to: Polygon Mumbai
Native Tokens: MATIC

### Security review scope (Unit Test and Coverage)
Hotelereum NFT Marketplace
Deployment
√ Should set the right Smart Contract owner (2319ms)
Oracle
√ Ask the oracle about MATIC price (117ms)
On-Chain Inventory
√ Should be able to enroll a hotel partner
√ Should be able to manage inventory with Proper Stable-Coin Value (71ms)
Super Admin NFT Mint
√ Should mint an NFT by the Smart Contract owner where guest will be the owner of NFT (48ms)
√ Should fail to mint if the sender is not actual Smart Contract owner
Regular Guest NFT Mint
√ Should mint if the sender is paying with crypto (117ms)
√ Should primary market stakeholder's crypto balances got updated after a successful mint (94ms)
NFT Reselling
√ Should mark an NFT for resell when the sender is the current NFT owner (52ms)
√ Should fail to mark NFT for resell when the sender is not the current NFT owner (46ms)
√ Should be able to purchase resellable NFT as hotel reservation (92ms)
√ Should secondary market stakeholder's crypto balances got updated after a successful sale (130ms)
Smart Contract Ownership Transfer
√ Should transfer the Smart Contract's ownership if the request is from current owner
√ Should fail to transfer the Smart Contract's ownership if the sender is not current Smart Contract owner

14 passing (3s)

| File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
| --- | --- | --- | --- | --- | --- |
|contracts | 97.22 | 53.45 | 91.3 | 96.91 | |
| HotelereumNFTMarketplace.sol | 97.22 | 53.45 | 91.3 | 96.91 | 46,183,595 |
|All files | 97.22 | 53.45 | 91.3 | 96.91 |

### Roles
- **Superadmin**
Owner of smart contract
- **Hotel organizations**
Hotel Partners
- **NFT owners**
Guests or reservation owners

### Known issues

- createCryptoBooking - client requested back to back changes which caused to create a lot more parameters
<mark>Struct will be introduced to deal with this issue </mark>

## Rekt Test (needs editing and spell check and icon adding)
- [x] Do you have all actors, roles and privileges documented?
- [x] Do you keep documentation of all the external services, contracts, and oracles you rely on?
- [ ] Do you have a written and tested incident response plan?
- [ ] Do you document the best ways to attack your system?
- [ ] Do you perform identity verification and background checks on all employees?
- [x] Do you have a team member with securtity defined in their role
- [ ] Do you require hardware security keys for production system (?)
- [ ] Does your key management system require multiple humans and physical steps? (?)(managed with ENV (12 Factor authentication))
- [x] Do you define key invariants for your system and test rthem on every commit?
- [x] Do you use the best automated tools to discover security issues in your code?
- [ ] Do you undergo external audits and maintain a vulneravbilitiy disclosue or bug bounty program?
- [x] Have you considered and mitigated avenues for abusing users of your system?

## Metrics report from .sol (Consensys Diligence)

### Files Summary

| Key | Value |
| --- | --- |
| .sol Files | 1 |
| Total nSLOC | 348 |

### Files Details

| Type | File | Logic Contracts | Interfaces | Lines | nLines | nSLOC | Comment Lines | Complex Score | Capabilities |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 📝🔍| HotelereumNFTMarketplace.sol | 1 | 1 | 601 | 502 | 348 | 109 | 165 |💰📤🔆Σ|

### Report Overview

The analysis finished with 0 errors and 0 duplicate files.

#### Risk

#### Inline documentation
- Comment to source ratio: On average there are4.09 code lines per comment (lower=better).

#### Components

## Issue Summary (From Aderyn)
Category | No. of Issues |
| --- | --- |
| Critical | 0 |
| High | 0 |
| Medium | 1 |
| Low | 1 |
| NC | 3 |

## Issues

### Medium Issues
- [ ] ***Centralization Issues***
Contracts have owners with privileged rights to perform admin tasks and need to be trusted to not perform malicious updates or drain funds.
- Found in contracts/HotelereumNFTMarketplace.sol [Line: 245](contracts/HotelereumNFTMarketplace.sol#L245)

	        onlyOwner

### Low Issues
- [ ] ***L-1: Unsafe ERC20 Operations should not be used***

ERC20 functions may not behave as expected. For example: return values are not always meaningful. It is recommended to use OpenZeppelin's SafeERC20 library.

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 410](contracts/HotelereumNFTMarketplace.sol#L410)

	        idToMarketItem[_tokenId].hotel.transfer(primaryHotelFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 411](contracts/HotelereumNFTMarketplace.sol#L411)

	        payable(owner()).transfer(primaryPlatformFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 436](contracts/HotelereumNFTMarketplace.sol#L436)

	        idToMarketItem[_tokenId].hotel.transfer(secondaryHotelFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 437](contracts/HotelereumNFTMarketplace.sol#L437)

	        payable(owner()).transfer(secondaryPlatformFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 438](contracts/HotelereumNFTMarketplace.sol#L438)

	        sellerWallet.transfer(secondaryOwnerFee);

### NC Issues

- [ ] ***NC-1: Functions not used internally could be marked external***

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 30](contracts/HotelereumNFTMarketplace.sol#L30)

	    function initialize(address _maticOracleRoute) public initializer {

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 322](contracts/HotelereumNFTMarketplace.sol#L322)

	    function createBookingTwin(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 358](contracts/HotelereumNFTMarketplace.sol#L358)

	    function createCryptoBookingTwin(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 492](contracts/HotelereumNFTMarketplace.sol#L492)

	    function markForResell(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 521](contracts/HotelereumNFTMarketplace.sol#L521)

	    function createFixMarketSale(uint256 _tokenId) public payable {

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 574](contracts/HotelereumNFTMarketplace.sol#L574)

	    function tokenURI(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 586](contracts/HotelereumNFTMarketplace.sol#L586)

	    function supportsInterface(

- [ ] ***NC-2: Constants should be defined and used instead of literals***

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 181](contracts/HotelereumNFTMarketplace.sol#L181)

	            return 82110000;

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 265](contracts/HotelereumNFTMarketplace.sol#L265)

	        return (_expirationDate - _startingDate) / 86400;

<mark>Mentioned in @dev tag</mark>

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 300](contracts/HotelereumNFTMarketplace.sol#L300)

	        uint256 rate = uint256(getLatestMaticPriceInUSD()) / 10 ** 2;

<mark>Decimal scaling for calculation purpose</mark>

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 305](contracts/HotelereumNFTMarketplace.sol#L305)

	                (10 ** 18) / rate;

<mark>Gas optimization purpose </mark>

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 408](contracts/HotelereumNFTMarketplace.sol#L408)

	            100;

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 409](contracts/HotelereumNFTMarketplace.sol#L409)

	        uint256 primaryHotelFee = (_amount * primaryHotelPercentage) / 100;

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 433](contracts/HotelereumNFTMarketplace.sol#L433)

	            secondaryPlatformFeePercentage) / 100;

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 434](contracts/HotelereumNFTMarketplace.sol#L434)

	        uint256 secondaryHotelFee = (_amount * secondaryHotelPercentage) / 100;

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 435](contracts/HotelereumNFTMarketplace.sol#L435)

	        uint256 secondaryOwnerFee = (_amount * secondaryOwnerPercentage) / 100;

<mark> All these are for storage gas optimization purpose </mark>

- [ ] ***NC-3: Does indexing cost outweigh storage costs (Follow up)***

Index event fields make the field more quickly accessible to off-chain tools that parse events. It should be checked if all events having indices are being emitted repeatedly.

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 102](contracts/HotelereumNFTMarketplace.sol#L102)

	    event InventoryItemCreated(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 121](contracts/HotelereumNFTMarketplace.sol#L121)

	    event MarketItemPayemt(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 128](contracts/HotelereumNFTMarketplace.sol#L128)

	    event PrimaryRevenueDistributed(

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 135](contracts/HotelereumNFTMarketplace.sol#L135)

	    event SecondaryRevenueDistributed(

## Issues Summary (Manual audit)

Category | No. of Issues |
| --- | --- |
| Critical | 0|
| High | 2 |
| Medium |1 |
| Low | 2|
| NC |5 |

## Issues

### Critical Issues

### High Issues
- [ ] ***H-1: initialize is a public function*** [Line 32]((contracts/HotelereumNFTMarketplace.sol#L435)).
It can be called by anyone and they may change important parameters of the contract or change the contract address.

function initialize(address _maticOracleRoute) public initializer

- [ ] ***H-2 : ERC20 used instead of IERC20***
- [ ] ERC20 functions may not behave as expected. For example: return values are not always meaningful. It is recommended to use OpenZeppelin's SafeERC20 library.

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 410](contracts/HotelereumNFTMarketplace.sol#L410)

	        idToMarketItem[_tokenId].hotel.transfer(primaryHotelFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 411](contracts/HotelereumNFTMarketplace.sol#L411)

	        payable(owner()).transfer(primaryPlatformFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 436](contracts/HotelereumNFTMarketplace.sol#L436)

	        idToMarketItem[_tokenId].hotel.transfer(secondaryHotelFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 437](contracts/HotelereumNFTMarketplace.sol#L437)

	        payable(owner()).transfer(secondaryPlatformFee);

- Found in contracts/HotelereumNFTMarketplace.sol [Line: 438](contracts/HotelereumNFTMarketplace.sol#L438)

	        sellerWallet.transfer(secondaryOwnerFee);

### Medium Issues
 
- [ ] ***M-1: Adding updatable function for enrolled entities***
 
### Low Issues

- [ ] ***L-1: use caching while using .length*** [line 255]((contracts/HotelereumNFTMarketplace.sol#L255))

for (uint i; i < _propertyIds.length; ) {
items[i] = hotelIdToInventory[_hotelId][_propertyIds[i]];
unchecked {
++i;
}
}

- [ ] ***L-2: use caching while using .length*** [line 284]((contracts/HotelereumNFTMarketplace.sol#L2))

for (uint i; i < _propertyIds.length; ) {
items[i] = hotelIdToInventory[_hotelId][_propertyIds[i]];
unchecked {
++i;
}
}

### NC Issues

- [ ] ***NC-1: Need to add natspec documentation*** [Line 32]((contracts/HotelereumNFTMarketplace.sol#L435))
 

- [ ] ***NC-2: Variable packing. must be careful while upgrading contract*** [Line 55](contracts/HotelereumNFTMarketplace.sol#L55)

***Storage Collision:*** In upgradable contracts, mixing up variable locations can cause storage collisions. This is extremely high Impact High likelihood error.

ThunderLoan.sol
uint256 private s_feePrecision;
uint256 private s_flashLoanFee; // 0.3% ETH fee

ThunderLoanUpgraded.sol
uint256 private s_flashLoanFee; // 0.3% ETH fee
uint256 public constant FEE_PRECISION = 1e18;

So in upgraded contract flashLoanFee will be replaced by feePrecision.


- [ ] ***NC-3: Events dont have natspec documentation*** [Line 104]((contracts/HotelereumNFTMarketplace.sol#L104))

- [ ] ***NC-4: Spelling Mistakes***

- Found in [Line:238](contracts/HotelereumNFTMarketplace.sol#L238)
- Found in [Line:320](contracts/HotelereumNFTMarketplace.sol#L320)
- Found in [Line:361](contracts/HotelereumNFTMarketplace.sol#L361)
- Found in [Line:411](contracts/HotelereumNFTMarketplace.sol#L411)

function primeryRevenueDistribution(
uint256 _tokenId,
uint256 _amount
) private {

- Found in [Line:531](contracts/HotelereumNFTMarketplace.sol#L531)

- [ ] ***NC-5: Inappropriate modifier naming*** [Line 163](contracts/HotelereumNFTMarketplace.sol#163)

modifier validHotelPartner(uint256 hotelId) {
require(hotelIdToWallet[hotelId] != address(0), "Invalid Hotel ID");
_;
}