QuickSwap and StellaSwap contest - CodingNameKiki's results

L-01. Some if statements do unnecessary fee calculations for zero amounts.

The following if statements return true if one of the variables is zero, so it's going to do the fee calculation anyway for the zero amount, which is unnecessary and wrongly applied.

a) Consider changing the if statement in the function collect()

(Before) - https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraPool.sol#L501-L507 (After) - https://gist.github.com/CodingNameKiki/16c3e7fefaf7a1b8dfbdbf78cd28843c

b) Consider changing the if statement in the function _recalculatePosition()

(Before) - https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraPool.sol#L256-L259 (After) - https://gist.github.com/CodingNameKiki/1328ecea08b921c1873db37a28610f6d

c) Consider changing the if statement in the function burn()

(Before) - https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraPool.sol#L528-L530 (After) - https://gist.github.com/CodingNameKiki/7e4e32a8ef392bca074db819016ae27f

L-02. Missing checks for address(0x0) when assigning values to address state variables in the constructor

Zero-address checks are a best practice for input validation of critical address parameters. While the codebase applies this to most cases, there are many places where this is missing in the following constructors. Impact: Accidental use of zero-addresses may result in exceptions, burn fees/tokens, or force redeployment of contracts.

https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraFactory.sol#L54-L55 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L33

L-03. Several critical operations do not trigger events, which will make it difficult to review the correct behavior of the contracts once deployed.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L546 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L44

L-04. Setters should check the input value.

Add a non-zero address check to the following functions ,so they can revert if a zero address is provided.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L77 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L84 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L91 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L959

L-05. Front-runable initializer

There is nothing preventing another account from calling the initializer before the contract owner. In the best case, the owner is forced to waste gas and re-deploy.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L193

L-06. Input array lengths may differ

If the caller makes a copy-paste error, the lengths may be mismatchd and an operation believed to have been completed may not in fact have been completed

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L171 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L88

L-07. Add a timelock to critical functions

It is a good practice to give time for users to react and adjust to critical changes. A timelock provides more guarantees and reduces the level of trust required, thus decreasing risk for users.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L952 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L967

N-01. Use two-phase ownership transfers

Consider adding a two-phase transfer, where the current owner nominates the next owner, and the next owner has to call accept*() to become the new owner. This prevents passing the ownership to an account that is unable to use it.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L77 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L84 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L959 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L36

N-02. require()/revert() statements should have descriptive reason strings

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L43 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L60 https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraFactory.sol#L62-L63 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L78 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L85 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L55 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L122 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L134 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L229 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L953 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L960 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L968 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L22 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L27 https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/AlgebraPoolDeployer.sol#L37-L38 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L43

N-03. Constants should be defined rather than using magic numbers

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L15 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L138 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L139 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L158

N-04. Not using the named return variables anywhere in the function is confusing

Consider changing the variable to be an unnamed one

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L551 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L561 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L110 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L120 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L131 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L150

N-05. Use scientific notation instead of exponentiation.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L138

N-06. Missing initializer modifier on constructor

It is recommended that the initializer modifier be applied to constructors https://forum.openzeppelin.com/t/uupsupgradeable-vulnerability-post-mortem/15680/5

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L15 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L32 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L7 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L14

N-07. Function Naming suggestions

Proper use of _ as a function name prefix A common pattern is to prefix internal and private function names with _.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L122 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L403

N-08. Proper use of get as a function name prefix

Clear function names can increase readability. Follow a standard convertion function names such as using get for getter (view/pure) functions.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L122 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/DataStorageOperator.sol#L145 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L70 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L74 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L79

N-09. Constant redefined elsewhere

Consider defining in only one contract so that values cannot become out of sync when only one location is updated. A cheap way to store constants in a single location is to create an internal constant in a library. If the variable is a local cache of another contract's value, consider making the cache variable internal or private, which will require external users to query the contract with the source of truth, so that callers don't get out of sync.

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L16 https://github.com/code-423n4/2022-09-quickswap/blob/main/src/core/contracts/DataStorageOperator.sol#L20-L21

N-10. Override function arguments that are unused should have the variable name removed or commented out to avoid compiler warnings

https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L59 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L77 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L84 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L91 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraFactory.sol#L98 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L103 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L416 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L488 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L513 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L891 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L952 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L959 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPool.sol#L967 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L36 https://github.com/code-423n4/2022-09-quickswap/blob/15ea643c85ed936a92d2676a7aabf739b210af39/src/core/contracts/AlgebraPoolDeployer.sol#L44

Using unchecked blocks to save gas

When it is not possible for the arithmetic operation to underflow or overflow. The operation should be unchecked to save gas.

1.Consider unchecking the following arithmetic operations:

• Line-L141-L143
• Line-L157-L159
• Line-L164-L166
• Line-L229
• Line-L247
• Line-252
• Line-L455-L455
• Line-L478-L482
• Line-L502-L503
• Line-L801
• Line-L810-L811
• Line-L859
• Line-L873-L874
• Line-L922
• Line-L931
• Line-L936
• Line-L945
• Line-L257-L258
• Line-L804-L805
• Line-L109
• Line-L45

Using "x += y" cost more gas than "x = x + y"

1.Consider using this method only for the following state variables

• Line-L811
• Line-L810
• Line-L922
• Line-L936

Cache storage values in memory to minimize the gas cost

The code can be optimized by minimizing the number of SLOADs, since SLOADs are more expensive than MLOADs.

1.Consider caching MAX_VOLUME_PER_LIQUIDITY in the following function

• Line-L140

Constants can be set as private to save gas

1.Consider declaring the constans UINT16_MODULO and MAX_VOLUME_PER_LIQUIDITY as private:

• Line-L15-L16

Splitting require() statements that use && saves gas

Instead of using the && operator in a single require statement to check multiple conditions,using multiple require statements with 1 condition per require statement will save 8 GAS per &&.

• Line-L110
• Line-L953
• Line-L968
• Line-L46

Copying state struct in memory is wrong and wastes gas

Using storage pointer instead of memory location can save a decent amount of gas.

1.One function in the contract AlgebraPool, use a memory location to retrieve the struct Cumulatives

• Line-L114
• Line-125

2.One function in the contract AlgebraPool, use a memory location to retrieve the struct UpdatePositionCache

• Line-L287

3.One function in the contract AlgebraPool, use a memory location to retrieve the struct SwapCalculationCache

• Line-L719

4.One function in the contract AlgebraPool, use a memory location to retrieve the struct PriceMovementCache

• Line-L779