Coinbase Smart Wallet - albahaca's results

1. Optimization of assert Statement in postOp Function

2. Optimization Proposal for Withdraw Function in MagicSpend Contract

3. Gas Optimization Report: Refactoring canSkipChainIdValidation Function

4. abi.encode() is less efficient than abi.encodePacked()

5. Avoid unnecessary public variables

6. Make 3 event parameters indexed when possible

7. internal functions not called by the contract should be removed to save deployment gas

8. Internal functions only called once can be inlined to save gas

9. Use assembly to calculate hashes to save gas

10. keccak256() should only need to be called on a specific string literal once

11. When possible, use assembly instead of unchecked{++i}

12. Don't compare boolean expressions to boolean literals

13. Optimize External Calls with Assembly for Memory Efficiency

14. Unlimited gas consumption risk due to external call recipients

15. Use inline assembly to access the chain ID

16. Shorten the array rather than copying to a new one

[G-01] Optimization of assert Statement in postOp Function

Reasoning for Change: While assert statements are useful for detecting unexpected conditions during development and testing, they are typically used to validate internal contract state rather than input parameters. In this context, using assert to validate an input parameter (mode) may not be the most appropriate approach, as it could lead to unexpected contract termination in case of failed assertions.

Change Made: To address this concern, the assert statement was replaced with a require statement. Unlike assert, require statements are used to validate external inputs and ensure that functions are called with valid parameters. By using require, the function will revert with a specific error message if the condition is not met, providing better transparency and user feedback.

File:  src/MagicSpend/MagicSpend.sol
150   assert(mode != PostOpMode.postOpReverted);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L150

[G-02] Optimization Proposal for Withdraw Function in MagicSpend Contract

The withdraw function in the MagicSpend contract is currently structured such that it first calls the _validateRequest function, which involves reading and writing storage variables, and then checks if the signature provided in the withdrawRequest is valid. However, this sequence could potentially lead to gas inefficiencies, as the expensive operation of validating the request occurs before checking if the signature is valid.

188 function withdraw(WithdrawRequest memory withdrawRequest) external {
        _validateRequest(msg.sender, withdrawRequest);

        if (!isValidWithdrawSignature(msg.sender, withdrawRequest)) {
            revert InvalidSignature();
        }

        if (block.timestamp > withdrawRequest.expiry) {
            revert Expired();
        }

        // reserve funds for gas, will credit user with difference in post op
        _withdraw(withdrawRequest.asset, msg.sender, withdrawRequest.amount);
    }

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L188-L194

• To optimize gas usage and improve efficiency, it's proposed to reorder the logic in the withdraw function as follows:

function withdraw(WithdrawRequest memory withdrawRequest) external {
    // First, check if the provided signature is invalid
    if (!isValidWithdrawSignature(msg.sender, withdrawRequest)) {
        revert InvalidSignature();
    }

    // Next, validate the request
    _validateRequest(msg.sender, withdrawRequest);

    // Check if the request has expired
    if (block.timestamp > withdrawRequest.expiry) {
        revert Expired();
    }

    // Reserve funds for gas and credit the user with the difference in post-op
    _withdraw(withdrawRequest.asset, msg.sender, withdrawRequest.amount);
}

By reordering the logic in this way, the expensive operation of validating the request in _validateRequest is deferred until after it is determined that the signature is valid. This ensures that gas is not wasted on unnecessary storage reads and writes if the signature check fails.

[G-03] Gas Optimization Report: Refactoring canSkipChainIdValidation Function

Reasons for Optimization: The original implementation of canSkipChainIdValidation relies on multiple logical OR operations to compare the given function selector against a set of predefined function selectors. However, each logical OR operation incurs additional gas costs. By refactoring the logic using inline assembly, we can potentially reduce gas consumption by consolidating the comparisons into a single operation.

File:  src/SmartWallet/CoinbaseSmartWallet.sol
    function canSkipChainIdValidation(bytes4 functionSelector) public pure returns (bool) {
        if (
            functionSelector == MultiOwnable.addOwnerPublicKey.selector
                || functionSelector == MultiOwnable.addOwnerAddress.selector
                || functionSelector == MultiOwnable.removeOwnerAtIndex.selector
                || functionSelector == UUPSUpgradeable.upgradeToAndCall.selector
        ) {
            return true;
        }
        return false;
    }

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L252-L26

Proposed Optimization: The proposed optimization involves using inline assembly to perform a bitwise OR operation on the function selector and compare it directly against a bitmask representing the combination of all targeted function selectors.

Implementation:

1. Define Function Selectors: First, we define the function selectors for the targeted functions (e.g., addOwnerPublicKey, addOwnerAddress, removeOwnerAtIndex, and upgradeToAndCall). These selectors are represented as hexadecimal values.

2. Bitwise OR Operation: Within the inline assembly block, we perform a bitwise OR operation (or) on the function selector with each of the predefined function selectors.

3. Compare with Targeted Selectors: The result of the bitwise OR operation is then compared (eq) against a bitmask representing the combination of all targeted function selectors.

4. Return Result: Finally, the result of the comparison is returned as a boolean value, indicating whether the given function selector matches any of the targeted function selectors.

[G-04] abi.encode() is less efficient than abi.encodePacked()

See for more information: https://github.com/ConnorBlockchain/Solidity-Encode-Gas-Comparison

There are 2 instance(s) of this issue:

• Bot find incorrectly this finding [G-04]

• note : there is no chance of collisions when you use abi.encodePacked in these instance

File:  src/SmartWallet/CoinbaseSmartWallet.sol
235  return keccak256(abi.encode(UserOperationLib.hash(userOp), entryPoint()));

321  return WebAuthn.verify({challenge: abi.encode(message), requireUV: false, webAuthnAuth: auth, x: x, y: y});

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L235

File:  src/SmartWallet/ERC1271.sol
134   return keccak256(abi.encode(_MESSAGE_TYPEHASH, hash));

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/ERC1271.sol#L134

[G-05] Avoid unnecessary public variables

Public state variables in Solidity automatically generate getter functions, increasing contract size and potentially leading to higher deployment and interaction costs. To optimize gas usage and contract efficiency, minimize the use of public variables unless external access is necessary. Instead, use internal or private visibility combined with explicit getter functions when required. This practice not only reduces contract size but also provides better control over data access and manipulation, enhancing security and readability. Prioritize lean, efficient contracts to ensure cost-effectiveness and better performance on the blockchain.

note: this instance missed from bots.

There are 1 instance(s) of this issue:

• the REPLAYABLE_NONCE_KEY public variable only use in CoinbaseSmartWallet contract change the visibility to save gas

File:  src/SmartWallet/CoinbaseSmartWallet.sol
43  uint256 public constant REPLAYABLE_NONCE_KEY = 8453;

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L43

[G-06] Make 3 event parameters indexed when possible

It is the most gas efficient to make up to 3 event parameters indexed. If there are less than 3 parameters, you need to make all parameters indexed.

There are 3 instances of this issue:

File:  src/MagicSpend/MagicSpend.sol
45    event MagicSpendWithdrawal(address indexed account, address indexed asset, uint256 amount, uint256 nonce);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L45

File:  src/SmartWallet/MultiOwnable.sol
68   event AddOwner(uint256 indexed index, bytes owner);

74   event RemoveOwner(uint256 indexed index, bytes owner);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/MultiOwnable.sol#L68

[G-07] internal functions not called by the contract should be removed to save deployment gas

If the functions are required by an interface, the contract should inherit from that interface and use the override keyword

File: src/SmartWallet/CoinbaseSmartWallet.sol
    function _domainNameAndVersion() internal pure override(ERC1271) returns (string memory, string memory) {
        return ("Coinbase Smart Wallet", "1");
    }

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L333:335

[G-08] Internal functions only called once can be inlined to save gas

Not inlining costs 20 to 40 gas because of two extra JUMP instructions and additional stack operations needed for function calls.

File: src/SmartWallet/CoinbaseSmartWallet.sol
291         function _validateSignature(bytes32 message, bytes calldata signature)

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L291

File: src/SmartWallet/ERC1271.sol
121         function _eip712Hash(bytes32 hash) internal view virtual returns (bytes32) {

133         function _hashStruct(bytes32 hash) internal view virtual returns (bytes32) {

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/ERC1271.sol#L133:133

File: src/SmartWallet/MultiOwnable.sol
201         function _checkOwner() internal view virtual {

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/MultiOwnable.sol#L201

[G-09] Use assembly to calculate hashes to save gas

Using assembly to calculate hashes can save 80 gas per instance

note: missed from bots

File: src/SmartWallet/CoinbaseSmartWalletFactory.sol
82              salt = keccak256(abi.encode(owners, nonce));

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWalletFactory.sol#L82

File: src/SmartWallet/ERC1271.sol
105                     keccak256(bytes(name)),

106                     keccak256(bytes(version)),

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/ERC1271.sol#L105

[G-10] keccak256() should only need to be called on a specific string literal once

It should be saved to an immutable variable, and the variable used instead. If the hash is being used as a part of a function selector, the cast to bytes4 should also only be done once.

File: src/SmartWallet/ERC1271.sol
104                     keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/ERC1271.sol#L104

[G-11] When possible, use assembly instead of unchecked{++i}

You can also use unchecked{++i;} for even more gas savings but this will not check to see if i overflows. For best gas savings, use inline assembly, however, this limits the functionality you can achieve.

//loop with unchecked{++i}
function uncheckedPlusPlusI() public pure {
    uint256 j = 0;
    for (uint256 i; i < 10; ) {
        j++;
        unchecked {
            ++i;
        }
    }
}

Gas: 1329

//loop with inline assembly
function inlineAssemblyLoop() public pure {
    assembly {
        let j := 0
        for {
            let i := 0
        } lt(i, 10) {
            i := add(i, 0x01)
        } {
            j := add(j, 0x01)
        }
    }
}

Gas: 709

File:  src/SmartWallet/CoinbaseSmartWallet.sol
206     for (uint256 i; i < calls.length;) {
            _call(calls[i].target, calls[i].value, calls[i].data);
            unchecked {
                ++i;
            }
        }

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L206-L211

[G-12] Don't compare boolean expressions to boolean literals

For cases of: if (<x> == true), use if (<x>) instead. For cases of: if (<x> == false), use if (!<x>) instead.

File: src/SmartWallet/CoinbaseSmartWalletFactory.sol
53              if (alreadyDeployed == false) {

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWalletFactory.sol#L53

[G-13] Optimize External Calls with Assembly for Memory Efficiency

Using interfaces to make external contract calls in Solidity is convenient but can be inefficient in terms of memory utilization. Each such call involves creating a new memory location to store the data being passed, thus incurring memory expansion costs. Inline assembly allows for optimized memory usage by re-using already allocated memory spaces or using the scratch space for smaller datasets. This can result in notable gas savings, especially for contracts that make frequent external calls. Additionally, using inline assembly enables important safety checks like verifying if the target address has code deployed to it using extcodesize(addr) before making the call, mitigating risks associated with contract interactions.

File:  src/MagicSpend/MagicSpend.sol
223  IEntryPoint(entryPoint()).withdrawTo(to, amount);

233  IEntryPoint(entryPoint()).addStake{value: amount}(unstakeDelaySeconds);

244  IEntryPoint(entryPoint()).unlockStake();

249  IEntryPoint(entryPoint()).withdrawStake(to);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L223

[G‑14] Unlimited gas consumption risk due to external call recipients

When calling an external function without specifying a gas limit , the called contract may consume all the remaining gas, causing the tx to be reverted. To mitigate this, it is recommended to explicitly set a gas limit when making low level external calls.

File:  src/SmartWallet/CoinbaseSmartWallet.sol
273  (bool success, bytes memory result) = target.call{value: value}(data);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L273

File:  src/MagicSpend/MagicSpend.sol
233   IEntryPoint(entryPoint()).addStake{value: amount}(unstakeDelaySeconds);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L233

[G‑15] Use inline assembly to access the chain ID

The original implementation uses the block.chainid global variable, while the optimized version employs inline assembly to access the chain ID, potentially reducing gas consumption.

File:  src/MagicSpend/MagicSpend.sol
284   block.chainid,

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/MagicSpend/MagicSpend.sol#L284

File:  src/SmartWallet/ERC1271.sol
52  chainId = block.chainid;

107   block.chainid,

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/ERC1271.sol#L52

[G-16] Shorten the array rather than copying to a new one

ASSEMBLY can be used to shorten the array by changing the length slot, so that the entries don't have to be copied to a new, shorter array

File:  src/SmartWallet/CoinbaseSmartWallet.sol
104   bytes[] memory owners = new bytes[](1);

https://github.com/code-423n4/2024-03-coinbase/blob/main/src/SmartWallet/CoinbaseSmartWallet.sol#L104

Description overview of The Smart Wallet

The Smart Wallet operates as a secure and versatile smart contract wallet, providing various functionalities for managing assets and authorizing transactions. Here's how it works:

1. Multiple Ownership:

   • The Smart Wallet supports multiple owners, allowing for up to 256 concurrent owners to manage the wallet's funds collaboratively.
   • Each owner can transact independently without requiring approval from other owners, enhancing flexibility and usability.

2. Owner Authentication:

   • Owners can authenticate themselves using either Ethereum addresses or passkeys.
   • Passkey owners' signatures are validated via WebAuthnSol, ensuring secure access to wallet functions.

3. User Operations:

   • Users can perform account-changing operations, such as updating owners or executing transactions, by signing user operations.
   • These user operations can be replayed across any EVM chain where the account has the same address, ensuring consistency and synchronicity across different chains.

4. ERC-4337 Compliance:

   • The Smart Wallet complies with the ERC-4337 standard, which defines a unified interface for smart contract wallets.
   • This compliance ensures interoperability with other ERC-4337-compliant contracts and services, facilitating seamless integration and usage.

5. Integration with Paymasters:

   • The Smart Wallet can be used with paymasters such as MagicSpend.
   • Paymasters facilitate signature-based withdrawals, allowing account owners to withdraw funds securely.
   • Additionally, MagicSpend supports using withdrawals to pay for transaction gas, providing a convenient and efficient way to execute transactions.

Overall, the Smart Wallet offers a comprehensive solution for secure asset management and transaction authorization, with support for multiple owners, flexible authentication methods, cross-chain compatibility, and integration with paymasters for seamless fund withdrawals and transaction execution.

How work the Smart Wallet Contracts

FCL.sol

Explanation of the Library:

The provided Solidity library, FCL, offers a set of functions and utilities for elliptic curve cryptography (ECC) operations, specifically focusing on ECDSA (Elliptic Curve Digital Signature Algorithm) verification.

Functionality of the Library:

1. ECDSA Verification: The library provides a function ecdsa_verify for verifying ECDSA signatures using the provided message hash, signature components (r and s), and public key (Qx and Qy).
2. Elliptic Curve Operations: Core functions enable basic elliptic curve operations, including point addition, doubling, scalar multiplication, and conversion between different point representations.
3. Supporting Functions: Additional utility functions assist in checking if a point is on the curve, computing modular inverses, and converting between different elliptic curve point representations.

MagicSpend.sol

Explanation of the contract:

The contract MagicSpend is an implementation of the ERC4337 Paymaster interface, compatible with Entrypoint v0.6. It facilitates withdrawing funds from the contract based on signed withdrawal requests.

Functionality of the contract:

1. Withdrawal Functionality: Users can withdraw funds by submitting withdrawal requests containing a signature, specifying the amount, and other parameters.
2. Nonce Management: The contract prevents replay attacks by tracking and validating the uniqueness of nonces used in withdrawal requests.
3. Gas Management: The contract handles gas-related operations, ensuring that sufficient funds are reserved for gas costs during withdrawal.
4. Owner Operations: Certain operations, such as withdrawing funds or interacting with the Entrypoint contract, can only be performed by the contract owner.
5. Entry Point Interactions: The contract facilitates interactions with an external Entrypoint contract, allowing operations such as depositing, withdrawing, and staking funds.

CoinbaseSmartWallet.sol

Explanation of the contract:

The contract CoinbaseSmartWallet is a smart contract wallet implementation based on the ERC4337 standard.

Functionality of the contract:

1. Wallet Operations: Users can execute calls, either individually or in batches, from the smart wallet contract to other contracts or accounts.
2. User Operation Validation: The contract provides a mechanism to validate user operations, ensuring that only authorized operations are executed.
3. Owner Management: The contract supports multiple owners, allowing them to manage the wallet collectively.
4. Signature Verification: Signature validation is implemented to authenticate user operations.
5. Upgradeable: The contract is upgradeable using the UUPSUpgradeable mechanism.

CoinbaseSmartWalletFactory.sol

Explanation of the contract:

The contract CoinbaseSmartWalletFactory is a factory contract responsible for deploying instances of CoinbaseSmartWallet contracts.

Functionality of the contract:

1. Account Deployment: The contract provides a function createAccount to deploy new instances of CoinbaseSmartWallet contracts.
2. Deterministic Address Generation: The contract offers a function getAddress to predict the deterministic address of the account created via createAccount.
3. Initialization Code Hash Retrieval: The contract exposes a function initCodeHash to retrieve the initialization code hash of the account.
4. Salt Calculation: The contract internally calculates a deterministic salt based on the provided set of initial owners and a nonce.

ERC1271.sol

Explanation of the contract:

The contract ERC1271 implements an abstract ERC-1271 interface with added functionality for cross-account replay protection.

Functionality of the contract:

1. Signature Validation: The contract provides a function isValidSignature to validate a signature against a given hash.
2. Replay-Safe Hashing: It offers a function replaySafeHash to produce a replay-safe hash from the given original hash.
3. Domain Separator: The contract calculates the domain separator used for creating EIP-712 compliant hashes.
4. EIP-712 Typed Hash: It calculates the EIP-712 typed hash of the CoinbaseSmartWalletMessage(bytes32 hash) data structure.
5. Hashing Functions: The contract provides internal functions to calculate the EIP-712 compliant hash and the hash of the data structure.

MultiOwnable.sol

Explanation of the contract:

The contract MultiOwnable is an authentication contract allowing multiple owners, each identified as bytes.

Functionality of the contract:

1. Storage Layout: The contract defines a structured storage layout to store owner-related information.
2. Owner Management: It allows adding and removing owners.
3. Owner Verification: The contract provides functions to check if an account is an owner.
4. Initialization: It offers an internal function to initialize the owners of the contract.
5. Access Control: The contract implements a modifier to restrict access to privileged functions to authorized owners.
6. Events: The contract emits events when adding or removing owners.

WebAuthn

Explanation of the library:

The WebAuthn library provides functionality for verifying WebAuthn Authentication Assertions.

Functionality of the library:

1. WebAuthn Assertion Verification: The library verifies WebAuthn Authentication Assertions.
2. Authenticator Data Parsing: It parses the authenticator data and client data JSON provided in the assertion.
3. Challenge Verification: Verifies that the challenge provided in the client data JSON matches the challenge provided by the relying party.
4. User Verification Check: Optionally verifies that user verification was enforced by the authenticator if required.
5. Signature Verification: Verifies the signature over the concatenated binary data of authenticator data and client data JSON.
6. Fallback Mechanism: If the RIP-7212 precompile for signature verification fails, it falls back to using FreshCryptoLib (FCL) for signature verification.

Approach Taken in Codebase Evaluation

Conducted a comprehensive analysis of each contract and library, focusing on functionality, security measures, and integration points. Identified potential vulnerabilities such as signature flaws and external dependency risks. Evaluated architecture, roles, event emission, and code quality. Assessed risks related to centralization, admin abuse, and technical complexities. Reviewed documentation for clarity and completeness. Provided actionable recommendations for security, code quality, architecture design, risk mitigation, and documentation enhancements.

Architecture Recommendations

CoinbaseSmartWallet.sol

1. Enhanced Signature Verification: Ensure robustness in signature verification mechanisms by employing well-tested cryptographic libraries and algorithms. Consider additional measures such as signature recovery to enhance security.

2. Nonce Security: Implement strict nonce management policies to prevent replay attacks. Utilize cryptographic randomness for nonce generation and enforce uniqueness across transactions.

3. External Contract Audits: Conduct security audits on external contracts, especially the Entrypoint contract, to identify and mitigate potential vulnerabilities. Regularly update and patch external dependencies to maintain security.

4. Gas Cost Estimation: Continuously monitor and refine gas cost estimation mechanisms to ensure accurate calculation. Reserve adequate funds for gas-related operations and handle gas-related errors gracefully.

5. Documentation and Testing: Provide comprehensive documentation covering contract functionality, security considerations, and usage guidelines. Conduct extensive testing, including unit tests and integration tests, to validate contract behavior under various scenarios and edge cases.

CoinbaseSmartWalletFactory.sol

1. Robust Access Control: Implement secure access control mechanisms to ensure that only authorized parties can deploy smart wallet instances. Utilize multi-factor authentication or threshold signatures for sensitive operations.

2. Nonce Handling: Implement strict nonce management policies to prevent nonce reuse and manipulation. Utilize cryptographic randomness for nonce generation and enforce nonce uniqueness across contract deployments.

3. Security Audits: Conduct thorough security audits of both the factory contract and the underlying ERC-4337 implementation. Regularly update and patch the implementation contract to address any discovered vulnerabilities.

4. Continuous Monitoring: Implement mechanisms for continuous monitoring and alerting to detect and respond to security incidents or suspicious activities promptly. Regularly review contract deployment logs and monitor contract state for anomalies or unauthorized access attempts.

ERC1271.sol

1. Robust Signature Verification: Implement rigorous signature verification mechanisms using well-established cryptographic libraries and algorithms. Conduct thorough testing to validate the correctness and effectiveness of the anti-cross-account-replay layer and signature verification logic.

2. Thorough Testing: Conduct extensive testing, including unit tests and integration tests, to validate the correctness and effectiveness of the anti-cross-account-replay layer and signature verification logic.

3. Constant Vigilance: Regularly monitor the contract for any suspicious activities or anomalies that may indicate potential security breaches or attacks. Implement mechanisms for real-time alerting and response to mitigate security risks promptly.

MultiOwnable.sol

1. Robust Access Control: Implement secure access control mechanisms to ensure that only authorized owners can perform privileged operations. Utilize multi-factor authentication or threshold signatures for critical owner operations.

2. Owner Validation: Thoroughly validate owner addresses or public keys to prevent impersonation or unauthorized ownership changes. Implement stringent validation checks to ensure the integrity of owner data.

3. Auditability: Ensure that owner management operations are auditable and traceable, with appropriate event logging and monitoring mechanisms in place. Maintain comprehensive logs of owner-related activities for accountability and transparency.

WebAuthn

1. Continuous Monitoring: Regularly monitor and update the contract to address any security vulnerabilities or emerging threats. Implement mechanisms for monitoring contract activity, gas usage, and potential anomalies that may indicate security breaches.

2. Code Audits: Conduct comprehensive code audits and security reviews to identify and mitigate potential vulnerabilities. Engage with security experts or auditing firms to perform thorough assessments of the contract codebase and address any identified issues promptly.

3. Secure Fallback Mechanism: Ensure that the fallback mechanism to FreshCryptoLib is secure and thoroughly tested to prevent any security risks or failures. Consider implementing additional safeguards or redundancy measures to mitigate risks associated with fallback procedures.

4. Data Integrity Checks: Implement robust checks to verify the integrity of the provided data and signatures to prevent tampering or manipulation. Use cryptographic hashing or checksum mechanisms to validate the authenticity of data inputs and outputs, especially when handling sensitive information.

5. Error Handling: Implement proper error handling mechanisms to gracefully handle unexpected situations and prevent potential exploits or vulnerabilities. Use informative error messages and logging functionalities to aid in debugging and troubleshooting, and ensure that error conditions are handled securely to prevent exploitation.

Codebase Quality Analysis

MagicSpend.sol

CoinbaseSmartWallet.sol

CoinbaseSmartWalletFactory.sol

ERC1271.sol

MultiOwnable.sol

WebAuthn.sol

Security Concerns

CoinbaseSmartWallet.sol

Security Concerns:

1. Signature Verification: Ensuring the robustness of signature verification is crucial to prevent unauthorized access to wallet functions. Any vulnerabilities in the signature verification process could lead to unauthorized fund transfers or contract manipulations.
2. Nonce Management: Proper management of nonces is essential to prevent replay attacks and ensure the integrity of transactions. Inadequate nonce handling could lead to unauthorized transaction execution or incorrect state changes.
3. Owner Management: Care should be taken to ensure that only authorized parties have access to owner management functions. Unauthorized owner modifications could lead to loss of control over the wallet or unauthorized fund transfers.
4. Upgradeability: While upgradeability provides flexibility for future enhancements, it also introduces security risks. Upgrades should be thoroughly tested and audited to prevent introducing vulnerabilities or breaking existing functionality.

CoinbaseSmartWalletFactory.sol

Security Concerns:

1. Owner Validation: It's crucial to ensure that the initial set of owners provided for account creation is valid and authorized to control the smart wallet. Lack of owner validation could result in unauthorized access to funds or contract manipulation.
2. Nonce Management: Proper management of the nonce parameter is essential to prevent address collisions and ensure the uniqueness of deployed contracts. Nonce reuse or manipulation could lead to unpredictable contract addresses or potential security vulnerabilities.
3. Implementation Security: The security of the deployed smart wallet instances depends on the integrity and robustness of the underlying ERC-4337 implementation. Vulnerabilities in the implementation contract could expose deployed wallets to various security risks.

ERC1271.sol

Security Concerns:

1. Signature Verification: The contract must ensure robust signature verification to prevent unauthorized access or manipulation of sensitive operations. Failure to properly validate signatures could lead to security vulnerabilities.
2. Replay Protection: Cross-account replay protection is essential to prevent signatures from being reused across different accounts. Any weakness in the replay protection mechanism could compromise the security of the system.
3. Domain Separator Integrity: The domain separator used for creating EIP-712 compliant hashes must be securely generated and protected to prevent attacks or manipulations that could compromise the uniqueness of the hashes.

MultiOwnable.sol

Security Concerns:

1. Unauthorized Access: Ensuring that only authorized owners can perform sensitive operations is critical to prevent unauthorized modifications to the contract state or execution of privileged functions.
2. Owner Validation: Proper validation of owner addresses or public keys is essential to prevent manipulation or spoofing of owner identities.
3. Owner Removal: Care must be taken when removing owners to prevent unintended removals or manipulation of ownership rights.
4. Storage Security: As the contract relies on storage for maintaining owner information, ensuring the integrity and security of the storage layout is crucial to prevent unauthorized access or tampering.

WebAuthn

Security Concerns:

1. Signature Malleability: The contract includes a guard against signature malleability to prevent manipulation of signatures.
2. Challenge and Data Verification: Ensuring that the challenge and data provided in the assertion are valid and unaltered is crucial for security.
3. Fallback Mechanism Safety: The fallback mechanism to FreshCryptoLib should be secure and reliable to prevent potential vulnerabilities or exploits.
4. Authenticator Data Integrity: Verifying the integrity of the authenticator data is essential to ensure that the assertion is genuine and not tampered with.
5. User Verification Enforcement: If user verification is required, ensuring that it was properly enforced by the authenticator is important for authentication security.

centralization Risks in detail:

FreshCryptoLib - FCL.sol

The FCL.sol contract introduces centralization risks due to its reliance on a specific precompiled contract address (MODEXP_PRECOMPILE). Precompiled contracts are compiled EVM bytecode that's embedded in Ethereum clients. If a specific precompiled contract is controlled by a single entity or becomes unavailable, it could lead to centralization risks. Any centralized control over this precompiled contract could potentially compromise the security and reliability of operations relying on it within the FCL.sol contract.

MagicSpend - MagicSpend.sol

In MagicSpend.sol, centralization risks stem from its use of the Ownable contract. The Ownable contract designates a single owner with complete control over the contract's functionalities. This centralization of power allows the owner to modify critical functions or withdraw funds without requiring consensus from other users or stakeholders. If the owner acts maliciously or negligently, it could undermine the decentralization principles of blockchain networks.

SmartWallet - CoinbaseSmartWallet.sol

The CoinbaseSmartWallet.sol contract exhibits centralization risks due to its extension of the MultiOwnable contract. While MultiOwnable allows for multi-signature ownership, it still retains centralization risks as multiple owners can collude to manipulate the contract's behavior. If the owners conspire to act against the interests of other users or stakeholders, they could abuse their combined authority to control the contract's functionalities.

CoinbaseSmartWalletFactory - CoinbaseSmartWalletFactory.sol

The centralization risks in CoinbaseSmartWalletFactory.sol arise from its control over the deployment of CoinbaseSmartWallet contracts. As the factory contract manages the creation of new smart wallets, any compromise or misuse of the factory contract could lead to centralization risks. If the factory contract is controlled by a single entity or becomes compromised, it could affect the deployment process of smart wallets, potentially impacting the decentralization of the ecosystem.

ERC1271 - ERC1271.sol

In ERC1271.sol, centralization risks emerge from its reliance on the ERC1271 abstract contract. Depending on the specific implementation of the ERC1271 interface, there could be centralization risks if the implementation allows for centralized control or introduces dependencies on centralized services. If the ERC1271 implementation is controlled by a single entity or relies on centralized services, it could compromise the decentralized nature of contract interactions relying on this interface.

MultiOwnable - MultiOwnable.sol

The MultiOwnable.sol contract introduces centralization risks through its mechanism for adding multiple owners. While it allows for distributed ownership, the process for adding owners might lack transparency or accountability, leading to centralization risks. If the owner registration process is controlled by a single entity or lacks proper oversight, it could undermine the decentralization principles of the contract.

WebAuthnSol - WebAuthn.sol

Centralization risks in WebAuthn.sol stem from its reliance on a specific precompiled contract address for signature verification in the "secp256r1" elliptic curve. Relying solely on a specific precompiled contract introduces centralization risks if the contract becomes unavailable or compromised. If the precompiled contract is controlled by a single entity or subject to external dependencies, it could undermine the decentralization and security of the authentication process relying on this contract.

Mechanism Review:

In each contract, the mechanism review section provides an analysis of the key mechanisms implemented within the codebase. This section evaluates the functionality, security, and efficiency of the mechanisms employed in the contracts. Here's an overview of the Mechanism Review section for each contract:

FreshCryptoLib - FCL.sol

• ECDSA Verification Mechanism: The code implements the ECDSA verification mechanism using elliptic curve cryptography (ECC), specifically the Short Weierstrass curve representation.
• Reliance on Precompiled Contract: It utilizes a precompiled contract address (MODEXP_PRECOMPILE) for certain operations, such as modular exponentiation, which could introduce centralization risks.

MagicSpend - MagicSpend.sol

• Withdrawal Mechanism: The contract implements a withdrawal mechanism where users can request withdrawals with a signed message. It utilizes signature verification to ensure the authenticity of withdrawal requests.
• Ownership Control: The contract relies on the Ownable contract, granting central ownership control over the contract's functionalities.

SmartWallet - CoinbaseSmartWallet.sol

• Signature Validation: The contract implements a mechanism for validating signatures (_validateSignature) to ensure that only authorized actions are performed.
• Ownership Structure: It extends the MultiOwnable contract, which allows for multi-signature ownership, distributing control among multiple owners.

CoinbaseSmartWalletFactory - CoinbaseSmartWalletFactory.sol

• Deterministic Address Generation: The contract deploys ERC-4337 accounts using a deterministic address generation approach, ensuring consistency and predictability in contract deployment.
• Proxy Deployment: It utilizes the ERC1967 proxy pattern for deploying CoinbaseSmartWallet contracts, facilitating upgradability and reducing deployment costs.

ERC1271 - ERC1271.sol

• Anti Cross-Account Replay Layer: The contract implements an anti cross-account replay layer to prevent replay attacks, enhancing the reliability of signature validation.
• Reliance on External Dependency: It imports the ERC1271 abstract contract, introducing centralization risks depending on the implementation and reliability of the ERC1271 interface.

MultiOwnable - MultiOwnable.sol

• Multi-Owner Storage: The contract efficiently manages owner-related data using a storage layout struct, enhancing readability and gas efficiency.
• Owner Addition and Removal: It provides functions to add and remove owners, ensuring that only authorized parties can modify the list of owners.

WebAuthnSol - WebAuthn.sol

• WebAuthnAuth Struct: The contract defines a struct to encapsulate WebAuthn authentication data, simplifying the management of authentication data.
• Signature Verification: It attempts to verify signatures using both a precompiled contract address and FreshCryptoLib (FCL), providing redundancy and reliability in the authentication process.

In summary, the Mechanism Review section evaluates the implementation of critical mechanisms within each contract, highlighting their functionality, security measures, and potential risks. This analysis provides valuable insights into the design and robustness of the contracts' core functionalities.

Systemic Risks:

In the context of each contract, systemic risks refer to potential vulnerabilities or weaknesses that could affect the overall integrity, security, or functionality of the system as a whole. Here's a breakdown of Systemic Risks for each contract:

FreshCryptoLib - FCL.sol

• Systemic Risks: The implementation heavily relies on low-level assembly instructions, which could introduce complexity and potential risks if not implemented correctly. Any flaws in the assembly code could compromise the overall security and reliability of the system.

MagicSpend - MagicSpend.sol

• Nonce Reuse Vulnerability: Despite attempts to mitigate nonce reuse through tracking used nonces per user, there's still a potential risk of replay attacks if nonces are reused unintentionally. Thorough testing and monitoring are necessary to ensure nonce uniqueness and prevent unauthorized fund withdrawals.

SmartWallet - CoinbaseSmartWallet.sol

• Nonce Management: The contract utilizes nonces for managing transactions, including a reserved nonce key for cross-chain replayable transactions. Flaws in the nonce generation or validation logic could compromise transaction security, leading to potential risks such as replay attacks.

CoinbaseSmartWalletFactory - CoinbaseSmartWalletFactory.sol

• Deployment Logic: The contract relies on the LibClone library for creating deterministic ERC1967 proxy contracts. Any vulnerabilities or flaws in the library's implementation could pose systemic risks affecting all deployed contracts, impacting the overall reliability and security of the system.

ERC1271 - ERC1271.sol

• Message Type Hash: The contract defines a constant representing the hash of the message type used in EIP-712 compliant hashing. Any changes or inconsistencies in the message type hash could lead to systemic risks affecting the integrity and security of signature validation, potentially compromising the reliability of the entire system.

MultiOwnable - MultiOwnable.sol

• Owner Indexing: The contract tracks the index of the next owner to add, facilitating efficient management of owner indices. However, systemic risks might arise if there are vulnerabilities or inaccuracies in the indexing mechanism, potentially affecting the integrity of owner data and ownership management.

WebAuthnSol - WebAuthn.sol

• Guard Against Signature Malleability: The contract includes a guard against signature malleability by checking the "s" value of the signature. However, any flaws in this mechanism could expose the system to systemic risks associated with signature manipulation attacks, compromising the overall security of the authentication process.

Technical Risks:

Technical risks pertain to potential vulnerabilities, weaknesses, or complexities within the technical implementation of each contract. Here's a detailed analysis of Technical Risks for each contract:

FreshCryptoLib - FCL.sol

• Signature Verification: Any vulnerabilities in the signature verification process could lead to unauthorized fund transfers or compromise the integrity of transactions. Thorough testing and auditing of the signature verification logic are essential to ensure its correctness and security.

MagicSpend - MagicSpend.sol

• Signature Verification: The heavy reliance on signature verification for withdrawal requests introduces technical risks. Any weaknesses in the signature validation logic could lead to unauthorized fund withdrawals or other security breaches.

SmartWallet - CoinbaseSmartWallet.sol

• Contract Upgrade: While upgradability can be beneficial, it introduces technical risks such as the potential for introducing vulnerabilities or unintended behavior during upgrades. Careful consideration and testing of upgrade mechanisms are necessary to mitigate these risks effectively.

CoinbaseSmartWalletFactory - CoinbaseSmartWalletFactory.sol

• Proxy Deployment: The use of proxy-based deployment introduces technical risks related to proxy logic, such as potential vulnerabilities or unintended behavior during upgrades. Thorough testing and auditing of the proxy deployment mechanism are crucial to ensure its reliability and security.

ERC1271 - ERC1271.sol

• EIP-712 Hash Calculation: Technical risks may arise if there are vulnerabilities or inaccuracies in the EIP-712 compliant hash calculation logic, leading to incorrect or insecure hashing of messages. Thorough testing and auditing of the hash calculation mechanism are necessary to ensure its correctness and robustness.

MultiOwnable - MultiOwnable.sol

• Storage Slot Access: The use of assembly to access storage slots for MultiOwnableStorage introduces technical risks. Errors or vulnerabilities in the assembly code could compromise the integrity of owner data or ownership management functionalities.

WebAuthnSol - WebAuthn.sol

• Client Data JSON Verification: Technical risks may arise if there are vulnerabilities in the JSON parsing or comparison mechanisms used for verifying client data integrity. Thorough testing and auditing of the JSON verification process are essential to ensure its reliability and security.

Integration Risks:

Integration risks refer to potential challenges or vulnerabilities arising from the interaction between different components or dependencies within the system. Here's a detailed analysis of Integration Risks for each contract:

FreshCryptoLib - FCL.sol

• Dependency Management: Any changes or issues with external precompiled contracts could introduce integration risks, affecting the functionality and reliability of the FreshCryptoLib contract. Regular audits and updates of dependencies are necessary to mitigate integration risks effectively.

MagicSpend - MagicSpend.sol

• Dependency Management: The contract relies on multiple external contracts and libraries for its functionality. Any vulnerabilities or changes in these dependencies could impact the security and functionality of the MagicSpend contract, highlighting the importance of regular audits and updates.

SmartWallet - CoinbaseSmartWallet.sol

• Dependency Management: The contract imports multiple external contracts and libraries, and any vulnerabilities or changes in these dependencies could impact its security and functionality. Regular audits and updates of dependencies are necessary to mitigate integration risks effectively.

CoinbaseSmartWalletFactory - CoinbaseSmartWalletFactory.sol

• Dependency Management: The contract relies on external libraries for proxy-based contract deployment. Any vulnerabilities or changes in these dependencies could impact the security and functionality of the factory contract, leading to integration risks across the ecosystem.

ERC1271 - ERC1271.sol

• Dependency Management: Integration risks may arise from dependencies on external contracts or libraries. Any vulnerabilities or changes in these dependencies could impact the functionality and security of the ERC1271 contract, highlighting the importance of thorough testing and compatibility checks.

MultiOwnable - MultiOwnable.sol

• Dependency Management: The contract relies on its own internal logic for multi-owner management. However, any dependencies on external contracts or libraries for related functionalities could introduce integration risks, requiring careful consideration and testing of integration dependencies.

WebAuthnSol - WebAuthn.sol

• Precompiled Contract Usage: The contract relies on a precompiled contract address for signature verification, and any discrepancies or changes in the precompiled contract could introduce integration risks. Close monitoring and updates may be necessary to ensure seamless integration with the precompiled contract.

Overall, addressing systemic, technical, and integration risks requires a comprehensive approach, including thorough testing, auditing, and regular updates to mitigate potential vulnerabilities and ensure the security and reliability of the entire system.

Time spent:

25 hours