Wateenswap - Smart Contract Audit Report
Audit Summary
Wateenswap is a decentralized exchange (DEX), allowing investors to swap BEP-20 tokens.
For this audit, we reviewed the following contracts on the Binance Smart Chain Testnet:
- Wateen, WateenERC20, and WateenPair contracts at 0x1a6040caD8FA0c2e40dE20d2F1f9e550a053960D.
- WateenFactory contract at 0x8D647321ea3A093a225A4c3b830443D9f2787fD8.
- WBNB contract at 0x1Cd4BC40A8Ee278F71c293E462b01ae0bAE7e0D4.
Audit Findings
No security issues were identifed.
Date: February 10th, 2022.
Contracts Overview
WateenERC20 Contract:
- The SafeMath library is utilized to prevent overflow/underflow attacks.
- The lock modifier is utilized to prevent re-entrancy where appropriate.
Wateen Contract:
- The WateenERC20 contract implements the BEP-20 standard for use as an LP token.
- This contract utilizes a 'permit' mechanism which allows the owner of the LP tokens to sign a transaction that enables another user to withdraw tokens and send them to the recipient. The recipient then submits the permit on behalf of the owner.
WateenPair Contract:
- The Wateen contract is responsible for the creation of liquidity pairs for the token, thereby enabling trading on the platform.
- At the time of deployment, the initialize() function is called from the WateenPair contract which allows the factory to specify the two BEP-20 tokens that this pair will exchange.
- Once the pool is created, its address is stored with a double mapping that takes both token addresses as input.
WateenRouter Contract:
- The WateenPair contract is the core Wateenswap functionality.
- Each Wateenswap Pair manages a liquidity pool made up of reserves of two BEP-20 tokens.
- This contract is responsible for tracking the balance of both tokens in the pair, as well as mints and burns of the LP token.
- Users can add liquidity by providing an equivalent value of each token and are minted an LP token in return. The LP tokens may be burned to receive the underlying assets at any time.
- Users may also exchange one token for an equivalent amount of the other token based on the current market value.
WBNB Contract:
- The WateenRouter contract is used to interact with the liquidity pool that was created in the WateenFactory contract.
- WateenRouter routes orders to the user-determined pair contract to swap assets.
- This contract performs requirement checks needed for swapping tokens, adding liquidity, and removing liquidity.
- The WBNB Contract implements a tokenized version of BNB that complies with the BEP-20 standard.
- WBNB is pegged to the value of BNB and is tradable on the Binance Smart Chain.
External Threat Results
| Vulnerability Category | Notes | Result |
|---|---|---|
| Arbitrary Storage Write | N/A | PASS |
| Arbitrary Jump | N/A | PASS |
| Centralization of Control | N/A | PASS |
| Delegate Call to Untrusted Contract | N/A | PASS |
| Dependence on Predictable Variables | N/A | PASS |
| Deprecated Opcodes | N/A | PASS |
| Ether Thief | N/A | PASS |
| Exceptions | N/A | PASS |
| External Calls | N/A | PASS |
| Flash Loans | N/A | PASS |
| Integer Over/Underflow | N/A | PASS |
| Logical Issues | N/A | PASS |
| Multiple Sends | N/A | PASS |
| Oracles | N/A | PASS |
| Suicide | N/A | PASS |
| State Change External Calls | N/A | PASS |
| Unchecked Retval | N/A | PASS |
| User Supplied Assertion | N/A | PASS |
| Critical Solidity Compiler | N/A | PASS |
| Overall Contract Safety | PASS |
WateenERC20, Wateen, and WateenPair Contracts
($) = payable function
# = non-constant function
+ [Int] IWateenFactory
- [Ext] feeTo
- [Ext] feeToSetter
- [Ext] getPair
- [Ext] allPairs
- [Ext] allPairsLength
- [Ext] createPair #
- [Ext] setFeeTo #
- [Ext] setFeeToSetter #
+ [Int] IWateenPair
- [Ext] name
- [Ext] symbol
- [Ext] decimals
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] allowance
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
- [Ext] DOMAIN_SEPARATOR
- [Ext] PERMIT_TYPEHASH
- [Ext] nonces
- [Ext] permit #
- [Ext] MINIMUM_LIQUIDITY
- [Ext] factory
- [Ext] token0
- [Ext] token1
- [Ext] getReserves
- [Ext] price0CumulativeLast
- [Ext] price1CumulativeLast
- [Ext] kLast
- [Ext] mint #
- [Ext] burn #
- [Ext] swap #
- [Ext] skim #
- [Ext] sync #
- [Ext] initialize #
+ [Int] IWateenERC20
- [Ext] name
- [Ext] symbol
- [Ext] decimals
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] allowance
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
- [Ext] DOMAIN_SEPARATOR
- [Ext] PERMIT_TYPEHASH
- [Ext] nonces
- [Ext] permit #
+ [Lib] SafeMath
- [Int] add
- [Int] sub
- [Int] mul
+ WateenERC20 (IWateenERC20)
- [Pub] #
- [Int] _mint #
- [Int] _burn #
- [Prv] _approve #
- [Prv] _transfer #
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
- [Ext] permit #
+ [Lib] Math
- [Int] min
- [Int] sqrt
+ [Lib] UQ112x112
- [Int] encode
- [Int] uqdiv
+ [Int] IERC20
- [Ext] name
- [Ext] symbol
- [Ext] decimals
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] allowance
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
+ [Int] IWateenCallee
- [Ext] WateenCall #
+ WateenPair (IWateenPair, WateenERC20)
- [Pub] getReserves
- [Prv] _safeTransfer #
- [Pub] #
- [Ext] initialize #
- [Prv] _update #
- [Prv] _mintFee #
- [Ext] mint #
- modifiers: lock
- [Ext] burn #
- modifiers: lock
- [Ext] swap #
- modifiers: lock
- [Ext] skim #
- modifiers: lock
- [Ext] sync #
- modifiers: lock
+ Wateen (IWateenFactory)
- [Pub] #
- [Ext] allPairsLength
- [Ext] createPair #
- [Ext] setFeeTo #
- [Ext] setFeeToSetter #
WateenRouter Contract
($) = payable function
# = non-constant function
+ [Int] IWateenFactory
- [Ext] feeTo
- [Ext] feeToSetter
- [Ext] getPair
- [Ext] allPairs
- [Ext] allPairsLength
- [Ext] createPair #
- [Ext] setFeeTo #
- [Ext] setFeeToSetter #
+ [Lib] TransferHelper
- [Int] safeApprove #
- [Int] safeTransfer #
- [Int] safeTransferFrom #
- [Int] safeTransferETH #
+ [Int] IWateen01
- [Ext] factory
- [Ext] WETH
- [Ext] addLiquidity #
- [Ext] addLiquidityETH ($)
- [Ext] removeLiquidity #
- [Ext] removeLiquidityETH #
- [Ext] removeLiquidityWithPermit #
- [Ext] removeLiquidityETHWithPermit #
- [Ext] swapExactTokensForTokens #
- [Ext] swapTokensForExactTokens #
- [Ext] swapExactETHForTokens ($)
- [Ext] swapTokensForExactETH #
- [Ext] swapExactTokensForETH #
- [Ext] swapETHForExactTokens ($)
- [Ext] quote
- [Ext] getAmountOut
- [Ext] getAmountIn
- [Ext] getAmountsOut
- [Ext] getAmountsIn
+ [Int] IWateen02 (IWateen01)
- [Ext] removeLiquidityETHSupportingFeeOnTransferTokens #
- [Ext] removeLiquidityETHWithPermitSupportingFeeOnTransferTokens #
- [Ext] swapExactTokensForTokensSupportingFeeOnTransferTokens #
- [Ext] swapExactETHForTokensSupportingFeeOnTransferTokens ($)
- [Ext] swapExactTokensForETHSupportingFeeOnTransferTokens #
+ [Int] IWateenPair
- [Ext] name
- [Ext] symbol
- [Ext] decimals
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] allowance
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
- [Ext] DOMAIN_SEPARATOR
- [Ext] PERMIT_TYPEHASH
- [Ext] nonces
- [Ext] permit #
- [Ext] MINIMUM_LIQUIDITY
- [Ext] factory
- [Ext] token0
- [Ext] token1
- [Ext] getReserves
- [Ext] price0CumulativeLast
- [Ext] price1CumulativeLast
- [Ext] kLast
- [Ext] mint #
- [Ext] burn #
- [Ext] swap #
- [Ext] skim #
- [Ext] sync #
- [Ext] initialize #
+ [Lib] SafeMath
- [Int] add
- [Int] sub
- [Int] mul
+ [Lib] WateenLibrary
- [Int] sortTokens
- [Int] pairFor
- [Int] getReserves
- [Int] quote
- [Int] getAmountOut
- [Int] getAmountIn
- [Int] getAmountsOut
- [Int] getAmountsIn
+ [Int] IERC20
- [Ext] name
- [Ext] symbol
- [Ext] decimals
- [Ext] totalSupply
- [Ext] balanceOf
- [Ext] allowance
- [Ext] approve #
- [Ext] transfer #
- [Ext] transferFrom #
+ [Int] IWETH
- [Ext] deposit ($)
- [Ext] transfer #
- [Ext] withdraw #
+ WateenRouter (IWateen02)
- [Pub] #
- [Ext] ($)
- [Int] _addLiquidity #
- [Ext] addLiquidity #
- modifiers: ensure
- [Ext] addLiquidityETH ($)
- modifiers: ensure
- [Pub] removeLiquidity #
- modifiers: ensure
- [Pub] removeLiquidityETH #
- modifiers: ensure
- [Ext] removeLiquidityWithPermit #
- [Ext] removeLiquidityETHWithPermit #
- [Pub] removeLiquidityETHSupportingFeeOnTransferTokens #
- modifiers: ensure
- [Ext] removeLiquidityETHWithPermitSupportingFeeOnTransferTokens #
- [Int] _swap #
- [Ext] swapExactTokensForTokens #
- modifiers: ensure
- [Ext] swapTokensForExactTokens #
- modifiers: ensure
- [Ext] swapExactETHForTokens ($)
- modifiers: ensure
- [Ext] swapTokensForExactETH #
- modifiers: ensure
- [Ext] swapExactTokensForETH #
- modifiers: ensure
- [Ext] swapETHForExactTokens ($)
- modifiers: ensure
- [Int] _swapSupportingFeeOnTransferTokens #
- [Ext] swapExactTokensForTokensSupportingFeeOnTransferTokens #
- modifiers: ensure
- [Ext] swapExactETHForTokensSupportingFeeOnTransferTokens ($)
- modifiers: ensure
- [Ext] swapExactTokensForETHSupportingFeeOnTransferTokens #
- modifiers: ensure
- [Pub] quote
- [Pub] getAmountOut
- [Pub] getAmountIn
- [Pub] getAmountsOut
- [Pub] getAmountsIn
WBNBContract
($) = payable function
# = non-constant function
+ WBNB
- [Pub] ($)
- [Pub] deposit ($)
- [Pub] withdraw #
- [Pub] totalSupply
- [Pub] approve #
- [Pub] transfer #
- [Pub] transferFrom #