test(ctb): reentrancy on relay (#3039)

Adds tests for reentrancy on message relaying.
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

packages/contracts-bedrock/.gas-snapshot

@@ -35,20 +35,21 @@ L1BlockTest:test_updateValues() (gas: 28216)
 L1BlockNumberTest:test_fallback() (gas: 18774)
 L1BlockNumberTest:test_getL1BlockNumber() (gas: 10657)
 L1BlockNumberTest:test_receive() (gas: 25437)
-L1CrossDomainMessenger_Test:testCannot_L1MessengerPause() (gas: 24561)
+L1CrossDomainMessenger_Test:testCannot_L1MessengerPause() (gas: 24539)
 L1CrossDomainMessenger_Test:testCannot_L1MessengerUnpause() (gas: 24508)
-L1CrossDomainMessenger_Test:test_L1MessengerMessageVersion() (gas: 24725)
-L1CrossDomainMessenger_Test:test_L1MessengerPause() (gas: 48017)
-L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageFirstStuckSecondSucceeds() (gas: 201762)
-L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageSucceeds() (gas: 77784)
-L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageToSystemContract() (gas: 67778)
-L1CrossDomainMessenger_Test:test_L1MessengerRelayShouldRevertIfPaused() (gas: 60493)
+L1CrossDomainMessenger_Test:test_L1MessengerMessageVersion() (gas: 24748)
+L1CrossDomainMessenger_Test:test_L1MessengerPause() (gas: 48061)
+L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageFirstStuckSecondSucceeds() (gas: 201827)
+L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageRevertsOnReentrancy() (gas: 195116)
+L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageSucceeds() (gas: 77762)
+L1CrossDomainMessenger_Test:test_L1MessengerRelayMessageToSystemContract() (gas: 67801)
+L1CrossDomainMessenger_Test:test_L1MessengerRelayShouldRevertIfPaused() (gas: 60471)
 L1CrossDomainMessenger_Test:test_L1MessengerReplayMessageWithValue() (gas: 38127)
-L1CrossDomainMessenger_Test:test_L1MessengerSendMessage() (gas: 297767)
-L1CrossDomainMessenger_Test:test_L1MessengerTwiceSendMessage() (gas: 1490070)
-L1CrossDomainMessenger_Test:test_L1MessengerUnpause() (gas: 40889)
+L1CrossDomainMessenger_Test:test_L1MessengerSendMessage() (gas: 297745)
+L1CrossDomainMessenger_Test:test_L1MessengerTwiceSendMessage() (gas: 1490048)
+L1CrossDomainMessenger_Test:test_L1MessengerUnpause() (gas: 40908)
 L1CrossDomainMessenger_Test:test_L1MessengerXDomainSenderReverts() (gas: 24249)
-L1CrossDomainMessenger_Test:test_L1MessengerxDomainMessageSenderResets() (gas: 86168)
+L1CrossDomainMessenger_Test:test_L1MessengerxDomainMessageSenderResets() (gas: 86191)
 L1StandardBridge_Test:test_depositERC20() (gas: 578867)
 L1StandardBridge_Test:test_depositERC20To() (gas: 581048)
 L1StandardBridge_Test:test_depositETH() (gas: 372975)
@@ -62,16 +63,17 @@ L1StandardBridge_Test:test_onlyL2BridgeFinalizeERC20Withdrawal() (gas: 36271)
 L1StandardBridge_Test:test_onlyPortalFinalizeERC20Withdrawal() (gas: 35600)
 L1StandardBridge_Test:test_receive() (gas: 519560)
 L2CrossDomainMessenger_Test:testCannot_L2MessengerPause() (gas: 10823)
+L2CrossDomainMessenger_Test:test_L1MessengerRelayMessageRevertsOnReentrancy() (gas: 171968)
 L2CrossDomainMessenger_Test:test_L2MessengerMessageVersion() (gas: 8455)
-L2CrossDomainMessenger_Test:test_L2MessengerPause() (gas: 31772)
-L2CrossDomainMessenger_Test:test_L2MessengerRelayMessageFirstStuckSecondSucceeds() (gas: 173026)
-L2CrossDomainMessenger_Test:test_L2MessengerRelayMessageSucceeds() (gas: 57288)
+L2CrossDomainMessenger_Test:test_L2MessengerPause() (gas: 31750)
+L2CrossDomainMessenger_Test:test_L2MessengerRelayMessageFirstStuckSecondSucceeds() (gas: 173004)
+L2CrossDomainMessenger_Test:test_L2MessengerRelayMessageSucceeds() (gas: 57311)
 L2CrossDomainMessenger_Test:test_L2MessengerRelayMessageToSystemContract() (gas: 36115)
 L2CrossDomainMessenger_Test:test_L2MessengerRelayShouldRevertIfPaused() (gas: 41578)
 L2CrossDomainMessenger_Test:test_L2MessengerSendMessage() (gas: 120536)
 L2CrossDomainMessenger_Test:test_L2MessengerTwiceSendMessage() (gas: 133720)
 L2CrossDomainMessenger_Test:test_L2MessengerXDomainSenderReverts() (gas: 10554)
-L2CrossDomainMessenger_Test:test_L2MessengerxDomainMessageSenderResets() (gas: 54754)
+L2CrossDomainMessenger_Test:test_L2MessengerxDomainMessageSenderResets() (gas: 54732)
 L2OutputOracleTest:testCannot_ProposeWithUnmatchedBlockhash() (gas: 26786)
 L2OutputOracleTest:testCannot_deleteL2Output_ifNotOwner() (gas: 24844)
 L2OutputOracleTest:testCannot_deleteL2Output_withWrongRoot() (gas: 91114)

packages/contracts-bedrock/contracts/test/CommonTest.t.sol

@@ -168,6 +168,8 @@ contract Messenger_Initializer is L2OutputOracle_Initializer {
 
     event WithdrawalFinalized(bytes32 indexed, bool success);
 
+    event WhatHappened(bool success, bytes returndata);
+
     function setUp() public virtual override {
         super.setUp();
 
@@ -419,3 +421,21 @@ contract Reverter {
         revert();
     }
 }
+
+// Useful for testing reentrancy guards
+contract CallerCaller {
+    event WhatHappened(
+        bool success,
+        bytes returndata
+    );
+
+    fallback() external {
+        (bool success, bytes memory returndata) = msg.sender.call(msg.data);
+        emit WhatHappened(success, returndata);
+        assembly {
+            switch success
+            case 0 { revert(add(returndata, 0x20), mload(returndata)) }
+            default { return(add(returndata, 0x20), mload(returndata)) }
+        }
+    }
+}

packages/contracts-bedrock/contracts/test/L1CrossDomainMessenger.t.sol

@@ -2,7 +2,7 @@
 pragma solidity 0.8.10;
 
 /* Testing utilities */
-import { Messenger_Initializer, Reverter } from "./CommonTest.t.sol";
+import { Messenger_Initializer, Reverter, CallerCaller } from "./CommonTest.t.sol";
 import { L2OutputOracle_Initializer } from "./L2OutputOracle.t.sol";
 
 /* Libraries */
@@ -266,4 +266,43 @@ contract L1CrossDomainMessenger_Test is Messenger_Initializer {
         assertEq(L1Messenger.successfulMessages(hash), true);
         assertEq(L1Messenger.receivedMessages(hash), true);
     }
+
+    // relayMessage: should revert if recipient is trying to reenter
+    function test_L1MessengerRelayMessageRevertsOnReentrancy() external {
+        address target = address(0xabcd);
+        address sender = PredeployAddresses.L2_CROSS_DOMAIN_MESSENGER;
+        bytes memory message = abi.encodeWithSelector(
+            L1Messenger.relayMessage.selector,
+            0,
+            sender,
+            target,
+            0,
+            0,
+            hex"1111"
+        );
+
+        bytes32 hash = Hashing.hashCrossDomainMessage(0, sender, target, 0, 0, message);
+
+        uint256 senderSlotIndex = 51;
+        vm.store(address(op), bytes32(senderSlotIndex), bytes32(abi.encode(sender)));
+        vm.etch(target, address(new CallerCaller()).code);
+
+        vm.expectEmit(true, true, true, true, target);
+
+        emit WhatHappened(false, abi.encodeWithSignature("Error(string)", "ReentrancyGuard: reentrant call"));
+
+        vm.prank(address(op));
+        vm.expectCall(target, message);
+        L1Messenger.relayMessage(
+            0, // nonce
+            sender,
+            target,
+            0, // value
+            0,
+            message
+        );
+
+        assertEq(L1Messenger.successfulMessages(hash), false);
+        assertEq(L1Messenger.receivedMessages(hash), true);
+    }
 }

packages/contracts-bedrock/contracts/test/L2CrossDomainMessenger.t.sol

 //SPDX-License-Identifier: MIT
 pragma solidity 0.8.10;
 
-import { Messenger_Initializer, Reverter } from "./CommonTest.t.sol";
+import { Messenger_Initializer, Reverter, CallerCaller } from "./CommonTest.t.sol";
 
 import { AddressAliasHelper } from "../vendor/AddressAliasHelper.sol";
 import { L2ToL1MessagePasser } from "../L2/L2ToL1MessagePasser.sol";
@@ -212,4 +212,42 @@ contract L2CrossDomainMessenger_Test is Messenger_Initializer {
         assertEq(L2Messenger.successfulMessages(hash), true);
         assertEq(L2Messenger.receivedMessages(hash), true);
     }
+
+    // relayMessage: should revert if recipient is trying to reenter
+    function test_L1MessengerRelayMessageRevertsOnReentrancy() external {
+        address target = address(0xabcd);
+        address sender = address(L1Messenger);
+        address caller = AddressAliasHelper.applyL1ToL2Alias(address(L1Messenger));
+        bytes memory message = abi.encodeWithSelector(
+            L2Messenger.relayMessage.selector,
+            0,
+            sender,
+            target,
+            0,
+            0,
+            hex"1111"
+        );
+
+        bytes32 hash = Hashing.hashCrossDomainMessage(0, sender, target, 0, 0, message);
+
+        vm.etch(target, address(new CallerCaller()).code);
+
+        vm.expectEmit(true, true, true, true, target);
+
+        emit WhatHappened(false, abi.encodeWithSignature("Error(string)", "ReentrancyGuard: reentrant call"));
+
+        vm.prank(caller);
+        vm.expectCall(target, message);
+        L2Messenger.relayMessage(
+            0, // nonce
+            sender,
+            target,
+            0, // value
+            0,
+            message
+        );
+
+        assertEq(L2Messenger.successfulMessages(hash), false);
+        assertEq(L2Messenger.receivedMessages(hash), true);
+    }
 }