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kupermind committed Feb 28, 2024
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2 changes: 2 additions & 0 deletions audits/README.md
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Expand Up @@ -21,6 +21,8 @@ An internal audit with a focus on `ERC20 bridging via fx-tunnel` is located in t

An internal audit with a focus on `Update for Community Multisig (CM)` is located in this folder: [internal audit 8](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/internal8).

An internal audit with a focus on `OptimismMesseger and WormholeMessenger` is located in this folder: [internal audit 9](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/internal9).

### External audit
Following the initial contracts [audit report](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/Valory%20Review%20Final.pdf),
the recommendations are addressed here: [feedback](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/Addressing%20Initial%20ApeWorX%20Recommentations.pdf).
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119 changes: 119 additions & 0 deletions audits/internal9/README.md
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# autonolas-governance-audit
The review has been performed based on the contract code in the following repository:<br>
`https://github.com/valory-xyz/autonolas-governance` <br>
commit: `50a336a2e31f980399f8c84ba6dad9cb9c673aaa` or `v1.1.10-pre-internal-audi` <br>

Update: 28-02-2024 <br>

## Objectives
The audit focused on governance using native bridging to Optimism/Base and Wormhole bridging to EVM-networks supported by Standard Relayer. <BR>

### Flatten version
Flatten version of contracts. [contracts](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/internal9/analysis/contracts)

### Coverage
Hardhat coverage has been performed before the audit and can be found here:
```sh
---------------------------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
OptimismMessenger.sol | 0 | 0 | 0 | 0 |... 163,164,169 |
WormholeMessenger.sol | 0 | 0 | 0 | 0 |... 201,202,207 |
```
Pay attention, please! No tests for contract on scope.

#### Wormhole security list
https://docs.wormhole.com/wormhole/quick-start/cross-chain-dev/standard-relayer#other-considerations
```
Receiving a message from relayer
Check for expected emitter [x]
call parseAndVerify on any additionalVAAs [N/A]
Replay protection [x]
Message Ordering
no guarantees on order of messages delivered [?] - requires discussion
Fowarding/Call Chaining - [x], by design
Refunding overpayment of gasLimit - [?] - requires discussion
Refunding overpayment of value sent - [?] - requires discussion
ref: https://github.com/wormhole-foundation/hello-wormhole/blob/main/src/extensions/HelloWormholeRefunds.sol
```

### Security issues
Details in [slither_full](https://github.com/valory-xyz/autonolas-governance/blob/main/audits/internal9/analysis/slither_full.txt) <br>
Notes: <br>
All is false positive.

### Possible optimization
##### Avoid casting
```
// Source governor address on L1 that is authorized to propagate the transaction execution across the bridge
address public sourceGovernor;
=>
set sourceGovernor in wormhole address format as bytes32
so avoid casting bytes32 to address EVM.
// Check for the source governor address
bytes32 governor = sourceGovernor;
if (governor != sourceAddress) {
revert SourceGovernorOnly(bridgeGovernor, governor);
}
ref: https://github.com/wormhole-foundation/wormhole-solidity-sdk/blob/main/src/Base.sol#L30C52-L30C74 SDK of Wormhole
```
##### Re-design contracts
Part of the code is common and has the nature of a repeatable pattern for all contracts. <br>
It makes sense to separate it into a separate contract and replace magic numbers (20,12,4) with constants.
```
// Check for the correct data length
uint256 dataLength = data.length;
if (dataLength < DEFAULT_DATA_LENGTH) {
revert IncorrectDataLength(DEFAULT_DATA_LENGTH, data.length);
}
// Unpack and process the data
for (uint256 i = 0; i < dataLength;) {
address target;
uint96 value;
uint32 payloadLength;
// solhint-disable-next-line no-inline-assembly
assembly {
// First 20 bytes is the address (160 bits)
i := add(i, 20)
target := mload(add(data, i))
// Offset the data by 12 bytes of value (96 bits)
i := add(i, 12)
value := mload(add(data, i))
// Offset the data by 4 bytes of payload length (32 bits)
i := add(i, 4)
payloadLength := mload(add(data, i))
}
// Check for the zero address
if (target == address(0)) {
revert ZeroAddress();
}
// Check for the value compared to the contract's balance
if (value > address(this).balance) {
revert InsufficientBalance(value, address(this).balance);
}
// Get the payload
bytes memory payload = new bytes(payloadLength);
for (uint256 j = 0; j < payloadLength; ++j) {
payload[j] = data[i + j];
}
// Offset the data by the payload number of bytes
i += payloadLength;
// Call the target with the provided payload
(bool success, ) = target.call{value: value}(payload);
if (!success) {
revert TargetExecFailed(target, value, payload);
}
}
```








173 changes: 173 additions & 0 deletions audits/internal9/analysis/contracts/OptimismMessenger-flatten.sol
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// Sources flattened with hardhat v2.20.1 https://hardhat.org

// Original license: SPDX_License_Identifier: MIT
pragma solidity ^0.8.23;

/// @dev Interface to the CrossDomainMessenger (CDM) Contract Proxy.
interface ICrossDomainMessenger {
function xDomainMessageSender() external returns (address);
}

/// @dev Provided zero address.
error ZeroAddress();

/// @dev Only self contract is allowed to call the function.
/// @param sender Sender address.
/// @param instance Required contract instance address.
error SelfCallOnly(address sender, address instance);

/// @dev Only `CDMContractProxyHome` is allowed to call the function.
/// @param sender Sender address.
/// @param CDMContractProxyHome Required CDM Contract Proxy (Home) address.
error CDMContractProxyHomeOnly(address sender, address CDMContractProxyHome);

/// @dev Only on behalf of `foreignGovernor` the function is allowed to process the data.
/// @param sender Sender address.
/// @param foreignGovernor Required Foreign Governor address.
error ForeignGovernorOnly(address sender, address foreignGovernor);

/// @dev Provided incorrect data length.
/// @param expected Expected minimum data length.
/// @param provided Provided data length.
error IncorrectDataLength(uint256 expected, uint256 provided);

/// @dev Provided value is bigger than the actual balance.
/// @param value Provided value.
/// @param balance Actual balance.
error InsufficientBalance(uint256 value, uint256 balance);

/// @dev Target execution failed.
/// @param target Target address.
/// @param value Provided value.
/// @param payload Provided payload.
error TargetExecFailed(address target, uint256 value, bytes payload);

/// @title OptimismMessenger - Smart contract for the governor home (Optimism) bridge implementation
/// @author Aleksandr Kuperman - <[email protected]>
/// @author Andrey Lebedev - <[email protected]>
/// @author Mariapia Moscatiello - <[email protected]>
contract OptimismMessenger {
event FundsReceived(address indexed sender, uint256 value);
event ForeignGovernorUpdated(address indexed foreignMessageSender);
event MessageReceived(address indexed foreignMessageSender, bytes data);

// Default payload data length includes the number of bytes of at least one address (20 bytes or 160 bits),
// value (12 bytes or 96 bits) and the payload size (4 bytes or 32 bits)
uint256 public constant DEFAULT_DATA_LENGTH = 36;
// CDM Contract Proxy (Home) address on L2 that receives the message across the bridge from the foreign L1 network
address public immutable CDMContractProxyHome;
// Foreign governor address on L1 that is authorized to propagate the transaction execution across the bridge
address public foreignGovernor;

/// @dev OptimismMessenger constructor.
/// @param _CDMContractProxyHome CDM Contract Proxy (Home) address (Optimism).
/// @param _foreignGovernor Foreign Governor address (ETH).
constructor(address _CDMContractProxyHome, address _foreignGovernor) {
// Check fo zero addresses
if (_CDMContractProxyHome == address(0) || _foreignGovernor == address(0)) {
revert ZeroAddress();
}

CDMContractProxyHome = _CDMContractProxyHome;
foreignGovernor = _foreignGovernor;
}

/// @dev Receives native network token.
receive() external payable {
emit FundsReceived(msg.sender, msg.value);
}

/// @dev Changes the Foreign Governor address (original Timelock).
/// @notice The only way to change the Foreign Governor address is by the Timelock on L1 to request that change.
/// This triggers a self-contract transaction of OptimismMessenger that changes the Foreign Governor address.
/// @param newForeignGovernor New Foreign Governor address.
function changeForeignGovernor(address newForeignGovernor) external {
// Check if the change is authorized by the previous governor itself
// This is possible only if all the checks in the message process function pass and the contract calls itself
if (msg.sender != address(this)) {
revert SelfCallOnly(msg.sender, address(this));
}

// Check for the zero address
if (newForeignGovernor == address(0)) {
revert ZeroAddress();
}

foreignGovernor = newForeignGovernor;
emit ForeignGovernorUpdated(newForeignGovernor);
}

/// @dev Processes a message received from the CDM Contract Proxy (Home) contract.
/// @notice The sender must be the Foreign Governor address (Timelock).
/// @param data Bytes message sent from the CDM Contract Proxy (Home) contract. The data must be encoded as a set of
/// continuous transactions packed into a single buffer, where each transaction is composed as follows:
/// - target address of 20 bytes (160 bits);
/// - value of 12 bytes (96 bits), as a limit for all of Autonolas ecosystem contracts;
/// - payload length of 4 bytes (32 bits), as 2^32 - 1 characters is more than enough to fill a whole block;
/// - payload as bytes, with the length equal to the specified payload length.
function processMessageFromForeign(bytes memory data) external payable {
// Check for the CDM Contract Proxy (Home) address
if (msg.sender != CDMContractProxyHome) {
revert CDMContractProxyHomeOnly(msg.sender, CDMContractProxyHome);
}

// Check for the Foreign Governor address
address governor = foreignGovernor;
address bridgeGovernor = ICrossDomainMessenger(CDMContractProxyHome).xDomainMessageSender();
if (bridgeGovernor != governor) {
revert ForeignGovernorOnly(bridgeGovernor, governor);
}

// Check for the correct data length
uint256 dataLength = data.length;
if (dataLength < DEFAULT_DATA_LENGTH) {
revert IncorrectDataLength(DEFAULT_DATA_LENGTH, data.length);
}

// Unpack and process the data
for (uint256 i = 0; i < dataLength;) {
address target;
uint96 value;
uint32 payloadLength;
// solhint-disable-next-line no-inline-assembly
assembly {
// First 20 bytes is the address (160 bits)
i := add(i, 20)
target := mload(add(data, i))
// Offset the data by 12 bytes of value (96 bits)
i := add(i, 12)
value := mload(add(data, i))
// Offset the data by 4 bytes of payload length (32 bits)
i := add(i, 4)
payloadLength := mload(add(data, i))
}

// Check for the zero address
if (target == address(0)) {
revert ZeroAddress();
}

// Check for the value compared to the contract's balance
if (value > address(this).balance) {
revert InsufficientBalance(value, address(this).balance);
}

// Get the payload
bytes memory payload = new bytes(payloadLength);
for (uint256 j = 0; j < payloadLength; ++j) {
payload[j] = data[i + j];
}
// Offset the data by the payload number of bytes
i += payloadLength;

// Call the target with the provided payload
(bool success, ) = target.call{value: value}(payload);
if (!success) {
revert TargetExecFailed(target, value, payload);
}
}

// Emit received message
emit MessageReceived(governor, data);
}
}
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