SLX Casino

Smart Contract Audit Report

Audit Summary

SLX Casino Audit Report SLX is building a new dice game where users can place over/under bets to win tokens.

For this audit, we reviewed the following contracts on the SX Network:

Audit Findings

Informational findings were identified and the team may want to review them. In addition, centralized aspects are present.
Date: December 21st, 2022.
Updated: December 22nd, 2022 to reflect updates made by the project team that resolves Findings #1 - #3.
Updated: December 27th, 2022 to reflect mainnet deployments.

Finding #1 - House - Medium (Resolved)

Description: The refundCustomBet() function deducts winnableAmount from lockedInBets, however lockedInBets is never increased in the contract. 
function refundCustomBet(
    address player,
    uint amount,
    uint winnableAmount,
    address _customToken
) external isHouseLive isAdmin {
    require(player != address(0), "Zero Address");
    require(amount > 0, "Amount is zero");
    lockedInBets -= winnableAmount;
    IERC20(_customToken).safeTransfer(player, amount);
}
Risk/Impact: All refund transactions will revert due to underflow as lockedInBets will always equal zero.
Recommendation: The refundCustomBet() function should instead decrease lockedInCustomBets[_customToken] by winnableAmount and the lockedInBets state variable should be removed to reduce contract size and deployment costs.
Resolution: The team has implemented the above recommendation.

Finding #2 - House - Informational (Resolved)

Description: The SetBalanceMaxProfitRatioForCustom event in the setBalanceMaxProfitRatioForCustom() function, improperly takes in balanceMaxProfitRatio as a parameter instead of balanceMaxProfitRatioForCustom. 
function setBalanceMaxProfitRatioForCustom(uint _balanceMaxProfitRatioForCustom) external onlyOwner {
    balanceMaxProfitRatioForCustom = _balanceMaxProfitRatioForCustom;
    emit SetBalanceMaxProfitRatioForCustom(balanceMaxProfitRatio);
}
Risk/Impact: The value emitted in the event will be inaccurate as the wrong variable is being passed in.
Recommendation: balanceMaxProfitRatioForCustom should be passed into the SetBalanceMaxProfitRatioForCustom event in the setBalanceMaxProfitRatioForCustom() function.
Resolution: The team has implemented the above recommendation.

Finding #3 - House - Informational (Resolved)

Description: The balanceMaxProfitRatio state variable is not utilized in the contract.
Recommendation: The balanceMaxProfitRatio state variable and setBalanceMaxProfitRatio() function should either be removed to reduce contract size and deployment costs or utilized in a way that fits the project team's intended functionality.
Resolution: The team has implemented the above recommendation.

Finding #4 - DiceManager - Informational

Description: The minBetAmount, maxBetAmount, and houseEdgeBP state variables serve no purpose as they are not utilized in any logic in any contracts.
Recommendation: These state variables and their respective setter functions should either be removed to reduce contract size and deployment costs or utilized in a way that fits the project team's intended functionality. As the contract is already deployed, this is merely informational.

Contracts Overview

  • As the contracts are implemented with Solidity v0.8.x, they are safe from any possible overflows/underflows.
Dice Contract:
  • Any user can place a custom bet by choosing a number between 3 and 11 and specifying whether the sum of two simulated 6-sided dice rolls will be over or under their chosen number.
  • The user will also specify a token address and a bet amount.
  • The token address must have been added to the team's custom token list in the House contract and the bet amount must exceed the minimum amount for the custom token.
  • A winnable amount is calculated by multiplying the user's bet amount by the team's custom multiplier value for the user's bet choice.
  • The winnable amount cannot exceed the maximum value for the custom token set by the team.
  • Upon placing a bet, a request ID is assigned to the bet in the QRNGManager via the airnodeRrp contract. The airnodeRrp contract was out of scope for this audit so our team is unable to provide an assessment with regard to security.
  • The user's placed bet is transferred to the House contract.
  • The QRNGManager contract can use this contract to determine the outcome of the bet.
  • If the bet is a winner, the calculated win amount is transferred from the House contract to the user.
  • The owner can set the minimum and maximum bet amounts for any address at any time.
  • The owner can enable/disable bet placing at any time.
  • The owner can update the House contract and QRNGManager contract addresses at any time.
  • The owner can withdraw any tokens from the contract to a recipient address at any time.
House Contract:
  • When placing a custom bet in the Dice contract, the amount of the custom token is transferred from the user to this contract and their bet is finalized.
  • When settling a bet, the calculated number of reward tokens are transferred from this contract to the winner's address.
  • Any Admin address can withdraw any custom tokens from the contract to a specified recipient at any time.
  • Any Admin address can refund any bet by transferring a specified number of tokens from the contract to a specified recipient at any time.
  • Any Admin can manually settle a bet by specifying an amount of a custom token to transfer from the contract to a recipient.
  • Any user can deposit any amount of ETH into the contract at any time.
  • The owner can enable/disable all bet placing and bet settling at any time.
  • The owner can add/remove addresses from the custom token list at any time. The team should exercise caution and ensure that only trusted tokens are added to the custom token list.
  • The owner can set the contract's balance maximum profit ratios to any values at any time.
  • The owner can add/remove any addresses from the Admin list at any time.
  • The owner can withdraw any tokens or ETH from the contract to a recipient address at any time.
QRNGManager Contract:
  • Any "Game" address can use this contract to initiate a full request via the airnodeRrp contract which intends to return a Request ID hash for a placed bet.
  • The airnodeRrp contract can fulfill a bet using the bet's request ID which intends to generate two random numbers that will be used in the Dice contract to determine the outcome of a bet. The random number generation relies on the use off-chain logic which has not been reviewed by our team.
  • The owner can add/remove addresses as a Game address at any time.
  • The owner can update the Airnode address, Sponsor wallet, and Endpoint value at any time.

Audit Results

Vulnerability Category Notes Result
Arbitrary Jump/Storage Write N/A PASS
Centralization of Control
  • The team can withdraw any tokens from the House contract at any time.
  • The team can manually settle a bet in the House contract at any time.
  • The owner can update the QRNGManager contract address in the Dice contract which is responsible for the random number generation at any time.
 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

Dice Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

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

 + [Int] IGame 
    - [Ext] settleBet #

 + [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] IHouse 
    - [Ext] placeCustomBet #
    - [Ext] settleCustomBet #
    - [Ext] refundCustomBet #
    - [Ext] balanceAvailableForCustomBet

 +  DiceManager (Ownable)
    - [Pub]  #
    - [Ext] setHouse #
       - modifiers: onlyOwner
    - [Ext] betsLength
    - [Ext] addCustomToken #
       - modifiers: onlyOwner
    - [Ext] setCustomMinBet #
       - modifiers: onlyOwner
    - [Ext] setCustomMaxBet #
       - modifiers: onlyOwner
    - [Ext] getCustomMinBet
    - [Pub] getCustomMaxBet
    - [Ext] toggleGameIsLive #
       - modifiers: onlyOwner
    - [Int] amountToWinnableAmount
    - [Ext] withdrawCustomTokenFunds #
       - modifiers: onlyOwner

 + [Int] IQRNGManager 
    - [Ext] makeRequestUint256 #
    - [Ext] isQRNG

 +  Dice (DiceManager, IGame)
    - [Pub]  #
       - modifiers: DiceManager
    - [Ext] setQRNG #
       - modifiers: onlyOwner
    - [Ext] placeCustomBet #
    - [Ext] settleBet #
    - [Prv] _settleBet #
    - [Int] _getResult

House Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
 +  Context 
    - [Int] _msgSender
    - [Int] _msgData

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

 + [Int] IGame 
    - [Ext] settleBet #

 + [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] IHouse 
    - [Ext] placeCustomBet #
    - [Ext] settleCustomBet #
    - [Ext] refundCustomBet #
    - [Ext] balanceAvailableForCustomBet

 +  House (Ownable, IHouse)
    - [Ext]  ($)
    - [Ext]  ($)
    - [Pub]  #
    - [Ext] deposit ($)
    - [Pub] customBalance
    - [Ext] toggleHouseLive #
       - modifiers: onlyOwner
    - [Ext] addCustomToken #
       - modifiers: onlyOwner
    - [Ext] removeCustomToken #
       - modifiers: onlyOwner
    - [Ext] setBalanceMaxProfitRatioForCustom #
       - modifiers: onlyOwner
    - [Ext] addAdmin #
       - modifiers: onlyOwner
    - [Ext] removeAdmin #
       - modifiers: onlyOwner
    - [Pub] balanceAvailableForCustomBet
    - [Pub] maxProfitForCustomBet
    - [Ext] placeCustomBet #
       - modifiers: isHouseLive,isAdmin,isCustomTokenActive
    - [Ext] settleCustomBet #
       - modifiers: isHouseLive,isAdmin,isCustomTokenActive
    - [Ext] sendTokens #
       - modifiers: isHouseLive,isAdmin
    - [Ext] refundCustomBet #
       - modifiers: isHouseLive,isAdmin
    - [Ext] withdrawFunds #
       - modifiers: onlyOwner
    - [Ext] withdrawCustomTokenFunds #
       - modifiers: onlyOwner

QRNGManager Contract

Smart Contract Audit - Inheritance

Smart Contract Audit - Graph


 ($) = payable function
 # = non-constant function
 
 Int = Internal
 Ext = External
 Pub = Public
 
 + [Int] IAuthorizationUtilsV0 
    - [Ext] checkAuthorizationStatus
    - [Ext] checkAuthorizationStatuses

 + [Int] ITemplateUtilsV0 
    - [Ext] createTemplate #
    - [Ext] getTemplates
    - [Ext] templates

 + [Int] IWithdrawalUtilsV0 
    - [Ext] requestWithdrawal #
    - [Ext] fulfillWithdrawal ($)
    - [Ext] sponsorToWithdrawalRequestCount

 + [Int] IAirnodeRrpV0 (IAuthorizationUtilsV0, ITemplateUtilsV0, IWithdrawalUtilsV0)
    - [Ext] setSponsorshipStatus #
    - [Ext] makeTemplateRequest #
    - [Ext] makeFullRequest #
    - [Ext] fulfill #
    - [Ext] fail #
    - [Ext] sponsorToRequesterToSponsorshipStatus
    - [Ext] requesterToRequestCountPlusOne
    - [Ext] requestIsAwaitingFulfillment

 +  RrpRequesterV0 
    - [Pub]  #

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

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

 + [Int] IGame 
    - [Ext] settleBet #

 + [Int] IQRNGManager 
    - [Ext] makeRequestUint256 #
    - [Ext] isQRNG

 +  QRNGManager (Ownable, RrpRequesterV0, IQRNGManager)
    - [Pub]  #
       - modifiers: RrpRequesterV0
    - [Ext] addGame #
       - modifiers: onlyOwner
    - [Ext] removeGame #
       - modifiers: onlyOwner
    - [Ext] setRequestParameters #
       - modifiers: onlyOwner
    - [Ext] setSponsorWallet #
       - modifiers: onlyOwner
    - [Prv] expand
    - [Ext] makeRequestUint256 #
       - modifiers: isGame
    - [Ext] fulfillUint256 #
       - modifiers: onlyAirnodeRrp
    - [Ext] isQRNG

About SourceHat

SourceHat has quickly grown to have one of the most experienced and well-equipped smart contract auditing teams in the industry. Our team has conducted 1800+ solidity smart contract audits covering all major project types and protocols, securing a total of over $50 billion U.S. dollars in on-chain value!
Our firm is well-reputed in the community and is trusted as a top smart contract auditing company for the review of solidity code, no matter how complex. Our team of experienced solidity smart contract auditors performs audits for tokens, NFTs, crowdsales, marketplaces, gambling games, financial protocols, and more!

Contact us today to get a free quote for a smart contract audit of your project!

What is a SourceHat Audit?

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.