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
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.
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 Locking the pragma helps to ensure that contracts do not accidentally get deployed using, for example, an outdated compiler version that might introduce bugs that affect the contract system negatively.
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
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.
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.
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