Frax Ether Liquid Staking contest - CodingNameKiki's results

A liquid ETH staking derivative designed to uniquely leverage the Frax Finance ecosystem.

General Information

Platform: Code4rena

Start Date: 22/09/2022

Pot Size: $30,000 USDC

Total HM: 12

Participants: 133

Period: 3 days

Judge: 0xean

Total Solo HM: 2

Id: 165

League: ETH

Frax Finance

Findings Distribution

Researcher Performance

Rank: 46/133

Findings: 3

Award: $58.05

🌟 Selected for report: 0

🚀 Solo Findings: 0

Awards

12.4859 USDC - $12.49

Labels

bug
duplicate
2 (Med Risk)

External Links

Lines of code

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L200

Vulnerability details

Impact

IERC20.transfer doesn't support all ERC20 tokens in the function recoverERC20(). https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L200

Proof of Concept

In the contract frxETHMinter, the function recoverERC20() is used to recover ERC20 tokens, if someone accidentally sent some of them in the contract. However there are some special tokens like USDT known for using non-standard ERC20, which doesn't return boolean on transfer.

Important: The transfer made with this ERC20 token will return void instead of bool. The call will revert even if the transfer is successful, because Solidity expects a return value. Using openzeppelin SafeERC20’s safetransfer instead of require won't help to transfer the tokens, it will just revert on failure.

Tools Used

VS Code

l recommend using solmate's SafeTransfer function in the contract "SafeTransferLib" instead of IERC20 transfer. This accepts ERC20 tokens with no boolean return like USDT. https://github.com/transmissions11/solmate/blob/main/src/utils/SafeTransferLib.sol#L63-L92

#0 - FortisFortuna

2022-09-25T21:28:58Z

Not really medium risk. Technically you could use safeTransfer, but if someone were to accidentally send something to this contract, it would most likely be either ETH, FRAX, frxETH, or sfrxETH, all of which are transfer compliant.

#1 - joestakey

2022-09-26T17:03:29Z

Duplicate of #18

Low risks - 13 instances found over 5 Low risk issues

L-01 approveMax variable causes problems The approveMax variable controls whether the liquidity value is used, or the maximum is used. If the result of that check doesn't match what was provided during signature generation, the permit() call will fail, so in the best case the variable has no effect. In the worst case it leads to incorrect state handling

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L68 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L84

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

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 constructors and setters. 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-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L41 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L34

L-03 Use of floating pragma

Contracts should be deployed with the same compiler version and flags that they have been tested with thoroughly. Locking the pragma helps to ensure that contracts do not accidentally get deployed using, for example, an outdated compiler version that might introduce bugs that affect the contract system negatively.

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L2 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L2 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETH.sol#L2 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L2 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L2

L-04 Return values of approve() not checked

Not all implementations revert() when there's a failure in approve(). The function signature has a boolean return value and they indicate errors that way instead. By not checking the return value, operations that should have marked as failed, may potentially go through without actually approving anything

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L75

L-05 Setters should check the input value.

Add a non-zero address check to the function transferMultiSig(), so it can revert if the newMultisag is a zero address.

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L70 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L166 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L199

Non-critical Issues - 20 instances found over 8 Non-critical issues

N-01 Public functions not called by the contract should be declared external instead

Contracts are allowed to override their parents functions and change the visibility from external to public. https://docs.soliditylang.org/en/latest/contracts.html#function-overriding

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L54 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L82 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L93 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L65 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L76 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L94

N-02 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-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L202 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L94

N-03 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-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L48 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L126

N-04 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-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L54 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L197

N-05 Event indexing

Events should use indexed fields

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L206 https://github.com/code-423n4/2022-09-frax/blob/main/src/OperatorRegistry.sol#L208-L214

N-06 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-frax/blob/main/src/frxETHMinter.sol#L45-L47

N-07 Constants should be defined rather than using magic numbers

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L38 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L39

N-08 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-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L70 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L67 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/sfrxETH.sol#L83

  1. No need to explicitly initialize variables with default values in for loops

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L129 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L63 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L84 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L114

  1. Use ++i instead of i++ in for loops.

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/ERC20/ERC20PermitPermissionedMint.sol#L84

  1. Use a memory location instead of storage

Using storage pointer instead of memory location can save a decent amount of gas. a) few functions in the contract OperatorRegistry, use a memory location to retrieve Validator https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L71 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L72 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L140

  1. ++i can be unchecked in the for loops.

There is no chance to overflow

https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/frxETHMinter.sol#L129 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L63 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L84 https://github.com/code-423n4/2022-09-frax/blob/55ea6b1ef3857a277e2f47d42029bc0f3d6f9173/src/OperatorRegistry.sol#L114

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