Merge branch 'main' into SMR-1814-2-IMX-withdraw-L1

src/child/ChildAxelarBridgeAdaptor.sol

@@ -60,7 +60,7 @@ contract ChildAxelarBridgeAdaptor is
         );
 
         gateway.callContract(_rootChain, _rootBridgeAdaptor, payload);
-        emit AxelarMessage(_rootChain, _rootBridgeAdaptor, payload);
+        emit AxelarMessageSent(_rootChain, _rootBridgeAdaptor, payload);
     }
 
     /**
@@ -71,6 +71,7 @@ contract ChildAxelarBridgeAdaptor is
         internal
         override
     {
+        emit AdaptorExecute(sourceChain_, sourceAddress_, payload_);
         childBridge.onMessageReceive(sourceChain_, sourceAddress_, payload_);
     }
 }

src/child/ChildERC20Bridge.sol

@@ -40,6 +40,7 @@ contract ChildERC20Bridge is
     bytes32 public constant DEPOSIT_SIG = keccak256("DEPOSIT");
     bytes32 public constant WITHDRAW_SIG = keccak256("WITHDRAW");
     address public constant NATIVE_ETH = address(0xeee);
+    address public constant NATIVE_IMX = address(0xfff);
 
     IChildERC20BridgeAdaptor public bridgeAdaptor;
 
@@ -109,20 +110,21 @@ contract ChildERC20Bridge is
         if (!Strings.equal(messageSourceChain, rootChain)) {
             revert InvalidSourceChain();
         }
-
         if (!Strings.equal(sourceAddress, rootERC20BridgeAdaptor)) {
             revert InvalidSourceAddress();
         }
-        if (data.length == 0) {
-            revert InvalidData();
+        if (data.length <= 32) {
+            // Data must always be greater than 32.
+            // 32 bytes for the signature, and at least some information for the payload
+            revert InvalidData("Data too short");
         }
 
         if (bytes32(data[:32]) == MAP_TOKEN_SIG) {
             _mapToken(data);
         } else if (bytes32(data[:32]) == DEPOSIT_SIG) {
             _deposit(data[32:]);
         } else {
-            revert InvalidData();
+            revert InvalidData("Unsupported action signature");
         }
     }
 
@@ -134,29 +136,65 @@ contract ChildERC20Bridge is
         _withdraw(childToken, receiver, amount);
     }
 
-    function _withdraw(IChildERC20 childToken, address receiver, uint256 amount) private {
-        if (address(childToken).code.length == 0) {
-            revert EmptyTokenContract();
-        }
+    function withdrawIMX(uint256 amount) external payable {
+        _withdrawIMX(msg.sender, amount);
+    }
 
-        address rootToken = childToken.rootToken();
+    function withdrawIMXTo(address receiver, uint256 amount) external payable {
+        _withdrawIMX(receiver, amount);
+    }
 
-        if (rootTokenToChildToken[rootToken] != address(childToken)) {
-            revert NotMapped();
+    function _withdrawIMX(address receiver, uint256 amount) private {
+        if (msg.value < amount) {
+            revert InsufficientValue();
         }
 
-        // A mapped token should never have root token unset
-        if (rootToken == address(0)) {
-            revert ZeroAddressRootToken();
+        uint256 expectedBalance = address(this).balance - (msg.value - amount);
+
+        _withdraw(IChildERC20(NATIVE_IMX), receiver, amount);
+
+        if (address(this).balance != expectedBalance) {
+            revert BalanceInvariantCheckFailed(address(this).balance, expectedBalance);
         }
+    }
 
-        // A mapped token should never have the bridge unset
-        if (childToken.bridge() != address(this)) {
-            revert BridgeNotSet();
+    function _withdraw(IChildERC20 childToken, address receiver, uint256 amount) private {
+        if (address(childToken) == address(0)) {
+            revert ZeroAddress();
         }
+        if (amount == 0) {
+            revert ZeroAmount();
+        }
+
+        address rootToken;
+        uint256 feeAmount = msg.value;
+
+        if (address(childToken) == NATIVE_IMX) {
+            feeAmount = msg.value - amount;
+            rootToken = rootIMXToken;
+        } else {
+            if (address(childToken).code.length == 0) {
+                revert EmptyTokenContract();
+            }
+            rootToken = childToken.rootToken();
+
+            if (rootTokenToChildToken[rootToken] != address(childToken)) {
+                revert NotMapped();
+            }
+
+            // A mapped token should never have root token unset
+            if (rootToken == address(0)) {
+                revert ZeroAddressRootToken();
+            }
+
+            // A mapped token should never have the bridge unset
+            if (childToken.bridge() != address(this)) {
+                revert IncorrectBridgeAddress();
+            }
 
-        if (!childToken.burn(msg.sender, amount)) {
-            revert BurnFailed();
+            if (!childToken.burn(msg.sender, amount)) {
+                revert BurnFailed();
+            }
         }
 
         // TODO Should we enforce receiver != 0? old poly contracts don't
@@ -165,9 +203,14 @@ contract ChildERC20Bridge is
         bytes memory payload = abi.encode(WITHDRAW_SIG, rootToken, msg.sender, receiver, amount);
 
         // Send the message to the bridge adaptor and up to root chain
-        bridgeAdaptor.sendMessage{value: msg.value}(payload, msg.sender);
 
-        emit ChildChainERC20Withdraw(rootToken, address(childToken), msg.sender, receiver, amount);
+        bridgeAdaptor.sendMessage{value: feeAmount}(payload, msg.sender);
+
+        if (address(childToken) == NATIVE_IMX) {
+            emit ChildChainNativeIMXWithdraw(rootToken, msg.sender, receiver, amount);
+        } else {
+            emit ChildChainERC20Withdraw(rootToken, address(childToken), msg.sender, receiver, amount);
+        }
     }
 
     function _mapToken(bytes calldata data) private {

src/interfaces/child/IChildAxelarBridgeAdaptor.sol

@@ -12,5 +12,7 @@ interface IChildAxelarBridgeAdaptorErrors {
 
 interface IChildAxelarBridgeAdaptorEvents {
     /// @notice Emitted when an Axelar message is sent to the root chain.
-    event AxelarMessage(string indexed rootChain, string indexed rootBridgeAdaptor, bytes indexed payload);
+    event AxelarMessageSent(string indexed rootChain, string indexed rootBridgeAdaptor, bytes indexed payload);
+    /// @notice Emitted when an Axelar message is received from the root chain.
+    event AdaptorExecute(string sourceChain, string sourceAddress_, bytes payload_);
 }

src/interfaces/child/IChildERC20.sol

@@ -25,8 +25,8 @@ interface IChildERC20 is IERC20MetadataUpgradeable {
     function bridge() external view returns (address);
 
     /**
-     * @notice Returns bridge address controlling the child token
-     * @return address Returns the address of the Bridge
+     * @notice Returns the address of the mapped token on the root chain
+     * @return address Returns the address of the root token
      */
     function rootToken() external view returns (address);
 

src/interfaces/child/IChildERC20Bridge.sol

@@ -32,6 +32,9 @@ interface IChildERC20BridgeEvents {
         address indexed receiver,
         uint256 amount
     );
+    event ChildChainNativeIMXWithdraw(
+        address indexed rootToken, address depositor, address indexed receiver, uint256 amount
+    );
 
     event ChildChainERC20Deposit(
         address indexed rootToken,
@@ -52,6 +55,10 @@ interface IChildERC20BridgeEvents {
 
 // TODO add parameters to errors if it makes sense
 interface IChildERC20BridgeErrors {
+    /// @notice Error when the amount requested is less than the value sent.
+    error InsufficientValue();
+    /// @notice Error when the withdrawal amount is zero
+    error ZeroAmount();
     /// @notice Error when the contract to mint had no bytecode.
     error EmptyTokenContract();
     /// @notice Error when the mint operation failed.
@@ -73,7 +80,7 @@ interface IChildERC20BridgeErrors {
     /// @notice Error when a message is given to the bridge from an address not the designated bridge adaptor.
     error NotBridgeAdaptor();
     /// @notice Error when the message's payload is not valid.
-    error InvalidData();
+    error InvalidData(string reason);
     /// @notice Error when the message's source chain is not valid.
     error InvalidSourceChain();
     /// @notice Error when the source chain's message sender is not a recognised address.
@@ -82,6 +89,10 @@ interface IChildERC20BridgeErrors {
     error ZeroAddressRootToken();
     /// @notice Error when a given child token's bridge address is not set.
     error BridgeNotSet();
+    /// @notice Error when a given child token's bridge address is incorrect.
+    error IncorrectBridgeAddress();
     /// @notice Error when a call to the given child token's `burn` function fails.
     error BurnFailed();
+    /// @notice Error when token balance invariant check fails.
+    error BalanceInvariantCheckFailed(uint256 actualBalance, uint256 expectedBalance);
 }

src/interfaces/root/IRootAxelarBridgeAdaptor.sol

@@ -14,5 +14,7 @@ interface IRootAxelarBridgeAdaptorErrors {
 
 interface IRootAxelarBridgeAdaptorEvents {
     /// @notice Emitted when an Axelar message is sent to the child chain.
-    event AxelarMessage(string indexed childChain, string indexed childBridgeAdaptor, bytes indexed payload);
+    event AxelarMessageSent(string indexed childChain, string indexed childBridgeAdaptor, bytes indexed payload);
+    /// @notice Emitted when an Axelar message is received from the child chain.
+    event AdaptorExecute(string sourceChain, string sourceAddress_, bytes payload_);
 }

src/interfaces/root/IRootERC20Bridge.sol

@@ -106,7 +106,7 @@ interface IRootERC20BridgeErrors {
     /// @notice Error when the given child chain bridge adaptor is invalid.
     error InvalidChildERC20BridgeAdaptor();
     /// @notice Error when a message received has invalid data.
-    error InvalidData();
+    error InvalidData(string reason);
     /// @notice Error when a message received has invalid source address.
     error InvalidSourceAddress();
     /// @notice Error when a message received has invalid source chain.

src/root/RootAxelarBridgeAdaptor.sol

@@ -78,7 +78,7 @@ contract RootAxelarBridgeAdaptor is
         );
 
         gateway.callContract(_childChain, _childBridgeAdaptor, payload);
-        emit AxelarMessage(_childChain, _childBridgeAdaptor, payload);
+        emit AxelarMessageSent(_childChain, _childBridgeAdaptor, payload);
     }
 
     /**
@@ -88,6 +88,7 @@ contract RootAxelarBridgeAdaptor is
         internal
         override
     {
+        emit AdaptorExecute(sourceChain_, sourceAddress_, payload_);
         rootBridge.onMessageReceive(sourceChain_, sourceAddress_, payload_);
     }
 }

src/root/RootERC20Bridge.sol

@@ -165,14 +165,16 @@ contract RootERC20Bridge is
         if (!Strings.equal(sourceAddress, childBridgeAdaptor)) {
             revert InvalidSourceAddress();
         }
-        if (data.length == 0) {
-            revert InvalidData();
+        if (data.length <= 32) {
+            // Data must always be greater than 32.
+            // 32 bytes for the signature, and at least some information for the payload
+            revert InvalidData("Data too short");
         }
 
         if (bytes32(data[:32]) == WITHDRAW_SIG) {
             _withdraw(data[32:]);
         } else {
-            revert InvalidData();
+            revert InvalidData("Unsupported action signature");
         }
     }
 
@@ -380,6 +382,6 @@ contract RootERC20Bridge is
             IERC20Metadata(rootToken).safeTransfer(receiver, amount);
         }
         // slither-disable-next-line reentrancy-events
-        emit RootChainERC20Withdraw(address(rootToken), childToken, withdrawer, receiver, amount);
+        emit RootChainERC20Withdraw(rootToken, childToken, withdrawer, receiver, amount);
     }
 }

test/integration/child/ChildAxelarBridge.t.sol

@@ -83,7 +83,7 @@ contract ChildERC20BridgeIntegrationTest is Test, IChildERC20BridgeEvents, IChil
         bytes32 commandId = bytes32("testCommandId");
         bytes memory payload = abi.encode("invalid payload");
 
-        vm.expectRevert(InvalidData.selector);
+        vm.expectRevert(abi.encodeWithSelector(InvalidData.selector, "Unsupported action signature"));
         childAxelarBridgeAdaptor.execute(commandId, ROOT_CHAIN_NAME, ROOT_ADAPTOR_ADDRESS, payload);
     }
 
@@ -109,7 +109,7 @@ contract ChildERC20BridgeIntegrationTest is Test, IChildERC20BridgeEvents, IChil
         bytes32 commandId = bytes32("testCommandId");
         bytes memory payload = "";
 
-        vm.expectRevert(InvalidData.selector);
+        vm.expectRevert(abi.encodeWithSelector(InvalidData.selector, "Data too short"));
         childAxelarBridgeAdaptor.execute(commandId, ROOT_CHAIN_NAME, ROOT_ADAPTOR_ADDRESS, payload);
     }
 

test/integration/child/withdrawals/ChildAxelarBridgeWithdraw.t.sol

@@ -106,14 +106,14 @@ contract ChildERC20BridgeWithdrawIntegrationTest is
         childBridge.withdraw{value: withdrawFee}(childToken, withdrawAmount);
     }
 
-    function test_withdraw_emits_AxelarMessageEvent() public {
+    function test_withdraw_emits_AxelarMessageSentEvent() public {
         ChildERC20 childToken = ChildERC20(childBridge.rootTokenToChildToken(rootToken));
 
         bytes memory predictedPayload =
             abi.encode(WITHDRAW_SIG, rootToken, address(this), address(this), withdrawAmount);
 
         vm.expectEmit(address(axelarAdaptor));
-        emit AxelarMessage(childBridge.rootChain(), childBridge.rootERC20BridgeAdaptor(), predictedPayload);
+        emit AxelarMessageSent(childBridge.rootChain(), childBridge.rootERC20BridgeAdaptor(), predictedPayload);
         childBridge.withdraw{value: withdrawFee}(childToken, withdrawAmount);
     }