STABLE-7554: Internal audit changes (circlefin#44)

src/MessageTransmitter.sol

@@ -247,12 +247,10 @@ contract MessageTransmitter is
      * of the attester address recovered from signatures.
      * @return success bool, true if successful
      */
-    function receiveMessage(bytes calldata message, bytes calldata attestation)
-        external
-        override
-        whenNotPaused
-        returns (bool success)
-    {
+    function receiveMessage(
+        bytes calldata message,
+        bytes calldata attestation
+    ) external override whenNotPaused returns (bool success) {
         // Validate each signature in the attestation
         _verifyAttestationSignatures(message, attestation);
 
@@ -313,10 +311,9 @@ contract MessageTransmitter is
      * to avoid impacting users who rely on large messages.
      * @param newMaxMessageBodySize new max message body size, in bytes
      */
-    function setMaxMessageBodySize(uint256 newMaxMessageBodySize)
-        external
-        onlyOwner
-    {
+    function setMaxMessageBodySize(
+        uint256 newMaxMessageBodySize
+    ) external onlyOwner {
         maxMessageBodySize = newMaxMessageBodySize;
         emit MaxMessageBodySizeUpdated(maxMessageBodySize);
     }
@@ -372,11 +369,10 @@ contract MessageTransmitter is
               destination
      * @return hash of source and nonce
      */
-    function _hashSourceAndNonce(uint32 _source, uint64 _nonce)
-        internal
-        pure
-        returns (bytes32)
-    {
+    function _hashSourceAndNonce(
+        uint32 _source,
+        uint64 _nonce
+    ) internal pure returns (bytes32) {
         return keccak256(abi.encodePacked(_source, _nonce));
     }
 

src/messages/v2/AddressUtils.sol

@@ -26,7 +26,7 @@ library AddressUtils {
      * @notice Converts an address to bytes32 by left-padding with zeros (alignment preserving cast.)
      * @param addr The address to convert to bytes32
      */
-    function addressToBytes32(address addr) internal pure returns (bytes32) {
+    function toBytes32(address addr) internal pure returns (bytes32) {
         return bytes32(uint256(uint160(addr)));
     }
 
@@ -36,7 +36,7 @@ library AddressUtils {
      * For use cases where this is not acceptable, validate that the first 12 bytes of _buf are zero-padding.
      * @param _buf the bytes32 to convert to address
      */
-    function bytes32ToAddress(bytes32 _buf) internal pure returns (address) {
+    function toAddress(bytes32 _buf) internal pure returns (address) {
         return address(uint160(uint256(_buf)));
     }
 }

src/messages/v2/MessageV2.sol

@@ -83,7 +83,7 @@ library MessageV2 {
         bytes32 _recipient,
         bytes32 _destinationCaller,
         uint32 _minFinalityThreshold,
-        bytes memory _messageBody
+        bytes calldata _messageBody
     ) internal pure returns (bytes memory) {
         return
             abi.encodePacked(

src/v2/BaseMessageTransmitter.sol

@@ -17,14 +17,9 @@
  */
 pragma solidity 0.7.6;
 
-import {IMessageTransmitterV2} from "../interfaces/v2/IMessageTransmitterV2.sol";
 import {Attestable} from "../roles/Attestable.sol";
 import {Pausable} from "../roles/Pausable.sol";
 import {Rescuable} from "../roles/Rescuable.sol";
-import {MessageV2} from "../messages/v2/MessageV2.sol";
-import {AddressUtils} from "../messages/v2/AddressUtils.sol";
-import {TypedMemView} from "@memview-sol/contracts/TypedMemView.sol";
-import {IMessageHandlerV2} from "../interfaces/v2/IMessageHandlerV2.sol";
 import {Initializable} from "../proxy/Initializable.sol";
 
 /**
@@ -85,7 +80,7 @@ contract BaseMessageTransmitter is
     /**
      * @notice Returns the current initialized version
      */
-    function initializedVersion() public view returns (uint64) {
+    function initializedVersion() external view returns (uint64) {
         return _getInitializedVersion();
     }
 }

src/v2/BaseTokenMessenger.sol

@@ -211,7 +211,7 @@ abstract contract BaseTokenMessenger is Rescuable, Denylistable, Initializable {
     /**
      * @notice Returns the current initialized version
      */
-    function initializedVersion() public view returns (uint64) {
+    function initializedVersion() external view returns (uint64) {
         return _getInitializedVersion();
     }
 
@@ -260,9 +260,7 @@ abstract contract BaseTokenMessenger is Rescuable, Denylistable, Initializable {
      * @return true if message sender is the registered local message transmitter
      */
     function _isLocalMessageTransmitter() internal view returns (bool) {
-        return
-            address(localMessageTransmitter) != address(0) &&
-            msg.sender == address(localMessageTransmitter);
+        return msg.sender == address(localMessageTransmitter);
     }
 
     /**

src/v2/FinalityThresholds.sol

@@ -20,7 +20,7 @@ pragma solidity 0.7.6;
 // The threshold at which (and above) messages are considered finalized.
 uint32 constant FINALITY_THRESHOLD_FINALIZED = 2000;
 
-// The threshold at which (and above) messages are considered finalized.
+// The threshold at which (and above) messages are considered confirmed.
 uint32 constant FINALITY_THRESHOLD_CONFIRMED = 1000;
 
 // The minimum allowed level of finality accepted by TokenMessenger

src/v2/MessageTransmitterV2.sol

@@ -56,9 +56,12 @@ contract MessageTransmitterV2 is IMessageTransmitterV2, BaseMessageTransmitter {
     );
 
     // ============ Libraries ============
+    using AddressUtils for address;
+    using AddressUtils for address payable;
+    using AddressUtils for bytes32;
+    using MessageV2 for bytes29;
     using TypedMemView for bytes;
     using TypedMemView for bytes29;
-    using MessageV2 for bytes29;
 
     // ============ Constructor ============
     /**
@@ -117,9 +120,13 @@ contract MessageTransmitterV2 is IMessageTransmitterV2, BaseMessageTransmitter {
         maxMessageBodySize = maxMessageBodySize_;
 
         // Attester configuration
-        for (uint256 i; i < attesters_.length; i++) {
+        uint256 _attestersLength = attesters_.length;
+        for (uint256 i; i < _attestersLength; ++i) {
             _enableAttester(attesters_[i]);
         }
+
+        // Claim 0-nonce
+        usedNonces[bytes32(0)] = 1;
     }
 
     // ============ External Functions  ============
@@ -147,7 +154,7 @@ contract MessageTransmitterV2 is IMessageTransmitterV2, BaseMessageTransmitter {
         );
         require(recipient != bytes32(0), "Recipient must be nonzero");
 
-        bytes32 _messageSender = AddressUtils.addressToBytes32(msg.sender);
+        bytes32 _messageSender = msg.sender.toBytes32();
 
         // serialize message
         bytes memory _message = MessageV2._formatMessageForRelay(
@@ -292,8 +299,7 @@ contract MessageTransmitterV2 is IMessageTransmitterV2, BaseMessageTransmitter {
         // Validate destination caller
         if (_msg._getDestinationCaller() != bytes32(0)) {
             require(
-                _msg._getDestinationCaller() ==
-                    AddressUtils.addressToBytes32(msg.sender),
+                _msg._getDestinationCaller() == msg.sender.toBytes32(),
                 "Invalid caller for message"
             );
         }
@@ -308,7 +314,7 @@ contract MessageTransmitterV2 is IMessageTransmitterV2, BaseMessageTransmitter {
         // Unpack remaining values
         _sourceDomain = _msg._getSourceDomain();
         _sender = _msg._getSender();
-        _recipient = AddressUtils.bytes32ToAddress(_msg._getRecipient());
+        _recipient = _msg._getRecipient().toAddress();
         _finalityThresholdExecuted = _msg._getFinalityThresholdExecuted();
         _messageBody = _msg._getMessageBody().clone();
     }

src/v2/TokenMessengerV2.sol

@@ -24,7 +24,6 @@ import {IRelayerV2} from "../interfaces/v2/IRelayerV2.sol";
 import {IMessageHandlerV2} from "../interfaces/v2/IMessageHandlerV2.sol";
 import {TypedMemView} from "@memview-sol/contracts/TypedMemView.sol";
 import {BurnMessageV2} from "../messages/v2/BurnMessageV2.sol";
-import {Initializable} from "../proxy/Initializable.sol";
 import {TOKEN_MESSENGER_MIN_FINALITY_THRESHOLD} from "./FinalityThresholds.sol";
 
 /**
@@ -62,9 +61,12 @@ contract TokenMessengerV2 is IMessageHandlerV2, BaseTokenMessenger {
     );
 
     // ============ Libraries ============
+    using AddressUtils for address;
+    using AddressUtils for address payable;
+    using AddressUtils for bytes32;
+    using BurnMessageV2 for bytes29;
     using TypedMemView for bytes;
     using TypedMemView for bytes29;
-    using BurnMessageV2 for bytes29;
 
     // ============ Constructor ============
     /**
@@ -122,7 +124,8 @@ contract TokenMessengerV2 is IMessageHandlerV2, BaseTokenMessenger {
         localMinter = ITokenMinterV2(tokenMinter_);
 
         // Remote messenger configuration
-        for (uint256 i; i < remoteDomains_.length; i++) {
+        uint256 _remoteDomainsLength = remoteDomains_.length;
+        for (uint256 i; i < _remoteDomainsLength; ++i) {
             require(
                 remoteTokenMessengers_[i] != bytes32(0),
                 "Invalid TokenMessenger"
@@ -344,10 +347,10 @@ contract TokenMessengerV2 is IMessageHandlerV2, BaseTokenMessenger {
         // Format message body
         bytes memory _burnMessage = BurnMessageV2._formatMessageForRelay(
             messageBodyVersion,
-            AddressUtils.addressToBytes32(_burnToken),
+            _burnToken.toBytes32(),
             _mintRecipient,
             _amount,
-            AddressUtils.addressToBytes32(msg.sender),
+            msg.sender.toBytes32(),
             _maxFee,
             _hookData
         );
@@ -398,7 +401,7 @@ contract TokenMessengerV2 is IMessageHandlerV2, BaseTokenMessenger {
         );
 
         return (
-            AddressUtils.bytes32ToAddress(_msg._getMintRecipient()),
+            _msg._getMintRecipient().toAddress(),
             _msg._getBurnToken(),
             _msg._getAmount()
         );
@@ -439,5 +442,6 @@ contract TokenMessengerV2 is IMessageHandlerV2, BaseTokenMessenger {
         // Validate fee
         _fee = _msg._getFeeExecuted();
         require(_fee == 0 || _fee < _amount, "Fee equals or exceeds amount");
+        require(_fee <= _msg._getMaxFee(), "Fee exceeds max fee");
     }
 }

test/examples/CCTPHookWrapper.t.sol

@@ -318,14 +318,16 @@ contract CCTPHookWrapperTest is Test {
         bytes memory _hookData
     ) internal pure returns (bytes memory) {
         return
-            MessageV2._formatMessageForRelay(
+            abi.encodePacked(
                 _messageVersion,
-                0,
-                0,
-                bytes32(0),
-                bytes32(0),
-                bytes32(0),
-                0,
+                uint32(0), // sourceDomain
+                uint32(0), // destinationDomain
+                bytes32(0), // nonce
+                bytes32(0), // sender
+                bytes32(0), // recipient
+                bytes32(0), // destinationCaller
+                uint32(0), // minFinalityThreshold
+                uint32(0), // finalityThresholdExecuted
                 _createBurnMessage(_messageBodyVersion, _hookData)
             );
     }

test/messages/v2/AddressUtils.t.sol

@@ -23,13 +23,13 @@ import {AddressUtils} from "../../../src/messages/v2/AddressUtils.sol";
 
 contract AddressUtilsTest is Test {
     function testAddressToBytes32Conversion(address _addr) public pure {
-        bytes32 _addrAsBytes32 = AddressUtils.addressToBytes32(_addr);
-        address _recoveredAddr = AddressUtils.bytes32ToAddress(_addrAsBytes32);
+        bytes32 _addrAsBytes32 = AddressUtils.toBytes32(_addr);
+        address _recoveredAddr = AddressUtils.toAddress(_addrAsBytes32);
         assertEq(_recoveredAddr, _addr);
     }
 
     function testAddressToBytes32LeftPads(address _addr) public pure {
-        bytes32 _addrAsBytes32 = AddressUtils.addressToBytes32(_addr);
+        bytes32 _addrAsBytes32 = AddressUtils.toBytes32(_addr);
 
         // addresses are 20 bytes, so the first 12 bytes should be 0 (left-padded)
         for (uint8 i; i < 12; i++) {

test/messages/v2/MessageV2.t.sol

@@ -35,7 +35,7 @@ contract MessageV2Test is Test {
         bytes32 _recipient,
         bytes32 _destinationCaller,
         uint32 _minFinalityThreshold,
-        bytes memory _messageBody
+        bytes calldata _messageBody
     ) public view {
         bytes memory _message = MessageV2._formatMessageForRelay(
             _version,
@@ -82,7 +82,7 @@ contract MessageV2Test is Test {
         bytes32 _recipient,
         bytes32 _destinationCaller,
         uint32 _minFinalityThreshold,
-        bytes memory _messageBody
+        bytes calldata _messageBody
     ) public {
         bytes memory _message = MessageV2._formatMessageForRelay(
             _version,