Add maxWithdraws to L2TokenBridge (#6)

Co-authored-by: telome <>
makerdao · Oct 1, 2024 · d0c8983 · d0c8983
1 parent a01b872
commit d0c8983
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Showing 6 changed files with 49 additions and 3 deletions.
diff --git a/deploy/L2TokenBridgeSpell.sol b/deploy/L2TokenBridgeSpell.sol
@@ -29,6 +29,7 @@ interface L2TokenBridgeLike {
     function deny(address) external;
     function close() external;
     function registerToken(address, address) external;
+    function setMaxWithdraw(address, uint256) external;
 }
 
 interface AuthLike {
@@ -54,6 +55,13 @@ contract L2TokenBridgeSpell {
             unchecked { ++i; }
         }
     }
+
+    function setMaxWithdraws(address[] memory l2Tokens, uint256[] memory maxWithdraws) public { 
+        for (uint256 i; i < l2Tokens.length;) {
+            l2Bridge.setMaxWithdraw(l2Tokens[i], maxWithdraws[i]);
+            unchecked { ++i; }
+        }
+    }
 
     function init(
         address l2GovRelay_,
@@ -62,7 +70,8 @@ contract L2TokenBridgeSpell {
         address l1Bridge,
         address l2Messenger,
         address[] calldata l1Tokens,
-        address[] calldata l2Tokens
+        address[] calldata l2Tokens,
+        uint256[] calldata maxWithdraws
     ) external {
         L2GovRelayLike l2GovRelay = L2GovRelayLike(l2GovRelay_);
 
@@ -75,5 +84,6 @@ contract L2TokenBridgeSpell {
         require(l2GovRelay.messenger() == l2Messenger, "L2TokenBridgeSpell/l2-gov-relay-messenger-mismatch");
 
         registerTokens(l1Tokens, l2Tokens);
+        setMaxWithdraws(l2Tokens, maxWithdraws);
     }
 }
diff --git a/deploy/TokenBridgeInit.sol b/deploy/TokenBridgeInit.sol
@@ -49,6 +49,7 @@ struct BridgesConfig {
     address l2Messenger;
     address[] l1Tokens;
     address[] l2Tokens;
+    uint256[] maxWithdraws;
     uint32 minGasLimit;
     bytes32 govRelayCLKey;
     bytes32 escrowCLKey;
@@ -73,6 +74,7 @@ library TokenBridgeInit {
         require(l1GovRelay.l2GovernanceRelay() == l2BridgeInstance.govRelay, "TokenBridgeInit/l2-gov-relay-mismatch");
         require(l1GovRelay.messenger() == cfg.l1Messenger, "TokenBridgeInit/l1-gov-relay-messenger-mismatch");
         require(cfg.l1Tokens.length == cfg.l2Tokens.length, "TokenBridgeInit/token-arrays-mismatch");
+        require(cfg.maxWithdraws.length == cfg.l2Tokens.length, "TokenBridgeInit/max-withdraws-length-mismatch");
         require(cfg.minGasLimit <= 1_000_000_000, "TokenBridgeInit/min-gas-limit-out-of-bounds");
 
         l1Bridge.file("escrow", address(escrow));
@@ -81,6 +83,7 @@ library TokenBridgeInit {
             (address l1Token, address l2Token) = (cfg.l1Tokens[i], cfg.l2Tokens[i]);
             require(l1Token != address(0), "TokenBridgeInit/invalid-l1-token");
             require(l2Token != address(0), "TokenBridgeInit/invalid-l2-token");
+            require(cfg.maxWithdraws[i] > 0, "TokenBridgeInit/max-withdraw-not-set");
             require(l1Bridge.l1ToL2Token(l1Token) == address(0), "TokenBridgeInit/existing-l1-token");
 
             l1Bridge.registerToken(l1Token, l2Token);
@@ -96,7 +99,8 @@ library TokenBridgeInit {
                 address(l1Bridge),
                 cfg.l2Messenger,
                 cfg.l1Tokens,
-                cfg.l2Tokens
+                cfg.l2Tokens,
+                cfg.maxWithdraws
             )),
             minGasLimit: cfg.minGasLimit
         });

diff --git a/script/Init.s.sol b/script/Init.s.sol
@@ -51,10 +51,14 @@ contract Init is Script {
         cfg.l2Messenger   = deps.readAddress(".l2Messenger");
         cfg.l1Tokens      = deps.readAddressArray(".l1Tokens");
         cfg.l2Tokens      = deps.readAddressArray(".l2Tokens");
+        cfg.maxWithdraws  = new uint256[](cfg.l2Tokens.length);
         cfg.minGasLimit   = 100_000;
         cfg.govRelayCLKey = l2Domain.readConfigBytes32FromString("govRelayCLKey");
         cfg.escrowCLKey   = l2Domain.readConfigBytes32FromString("escrowCLKey");
         cfg.l1BridgeCLKey = l2Domain.readConfigBytes32FromString("l1BridgeCLKey");
+        for (uint256 i; i < cfg.maxWithdraws.length; ++i) {
+            cfg.maxWithdraws[i] = 10_000_000 ether;
+        }
 
         L1TokenBridgeInstance memory l1BridgeInstance = L1TokenBridgeInstance({
             govRelay: deps.readAddress(".l1GovRelay"),

diff --git a/src/L2TokenBridge.sol b/src/L2TokenBridge.sol
@@ -32,6 +32,7 @@ contract L2TokenBridge {
 
     mapping(address => uint256) public wards;
     mapping(address => address) public l1ToL2Token;
+    mapping(address => uint256) public maxWithdraws;
     uint256 public isOpen = 1;
 
     // --- immutables ---
@@ -45,6 +46,7 @@ contract L2TokenBridge {
     event Deny(address indexed usr);
     event Closed();
     event TokenSet(address indexed l1Token, address indexed l2Token);
+    event MaxWithdrawSet(address indexed l2Token, uint256 maxWithdraw);
     event ERC20BridgeInitiated(
         address indexed localToken,
         address indexed remoteToken,
@@ -112,6 +114,11 @@ contract L2TokenBridge {
         emit TokenSet(l1Token, l2Token);
     }
 
+    function setMaxWithdraw(address l2Token, uint256 maxWithdraw) external auth {
+        maxWithdraws[l2Token] = maxWithdraw;
+        emit MaxWithdrawSet(l2Token, maxWithdraw);
+    }
+
     // -- bridging --
 
     function _initiateBridgeERC20(
@@ -124,6 +131,7 @@ contract L2TokenBridge {
     ) internal {
         require(isOpen == 1, "L2TokenBridge/closed"); // do not allow initiating new xchain messages if bridge is closed
         require(_localToken != address(0) && l1ToL2Token[_remoteToken] == _localToken, "L2TokenBridge/invalid-token");
+        require(_amount <= maxWithdraws[_localToken], "L2TokenBridge/amount-too-large");
 
         TokenLike(_localToken).burn(msg.sender, _amount); // TODO: should l2Tokens allow authed burn?
 

diff --git a/test/Integration.t.sol b/test/Integration.t.sol
@@ -121,11 +121,14 @@ contract IntegrationTest is DssTest {
         l1Tokens[0] = address(l1Token);
         address[] memory l2Tokens = new address[](1);
         l2Tokens[0] = address(l2Token);
+        uint256[] memory maxWithdraws = new uint256[](1);
+        maxWithdraws[0] = 10_000_000 ether;
         BridgesConfig memory cfg = BridgesConfig({
             l1Messenger:   L1_MESSENGER,
             l2Messenger:   L2_MESSENGER,
             l1Tokens:      l1Tokens,
             l2Tokens:      l2Tokens,
+            maxWithdraws:  maxWithdraws,
             minGasLimit:   1_000_000,
             govRelayCLKey: "BASE_GOV_RELAY",
             escrowCLKey:   "BASE_ESCROW",
@@ -148,6 +151,7 @@ contract IntegrationTest is DssTest {
 
         // test L2 side of initBridges
         assertEq(l2Bridge.l1ToL2Token(address(l1Token)), address(l2Token));
+        assertEq(l2Bridge.maxWithdraws(address(l2Token)), 10_000_000 ether);
         assertEq(l2Token.wards(address(l2Bridge)), 1);
     }
 

diff --git a/test/L2TokenBridge.t.sol b/test/L2TokenBridge.t.sol
@@ -26,6 +26,7 @@ import { MessengerMock } from "test/mocks/MessengerMock.sol";
 contract L2TokenBridgeTest is DssTest {
 
     event TokenSet(address indexed l1Address, address indexed l2Address);
+    event MaxWithdrawSet(address indexed l2Token, uint256 maxWithdraw);
     event Closed();
     event ERC20BridgeInitiated(
         address indexed localToken,
@@ -66,6 +67,7 @@ contract L2TokenBridgeTest is DssTest {
         l2Token.transfer(address(0xe0a), 500_000 ether);
         l2Token.rely(address(bridge));
         bridge.registerToken(l1Token, address(l2Token));
+        bridge.setMaxWithdraw(address(l2Token), 1_000_000 ether);
     }
 
     function testConstructor() public {
@@ -88,7 +90,8 @@ contract L2TokenBridgeTest is DssTest {
 
         checkModifier(address(bridge), string(abi.encodePacked("L2TokenBridge", "/not-authorized")), [
             bridge.close.selector,
-            bridge.registerToken.selector
+            bridge.registerToken.selector,
+            bridge.setMaxWithdraw.selector
         ]);
     }
 
@@ -102,6 +105,16 @@ contract L2TokenBridgeTest is DssTest {
         assertEq(bridge.l1ToL2Token(address(11)), address(22));
     }
 
+    function testSetmaxWithdraw() public {
+        assertEq(bridge.maxWithdraws(address(22)), 0);
+
+        vm.expectEmit(true, true, true, true);
+        emit MaxWithdrawSet(address(22), 123);
+        bridge.setMaxWithdraw(address(22), 123);
+
+        assertEq(bridge.maxWithdraws(address(22)), 123);
+    }
+
     function testClose() public {
         assertEq(bridge.isOpen(), 1);
 
@@ -132,6 +145,9 @@ contract L2TokenBridgeTest is DssTest {
         vm.expectRevert("L2TokenBridge/invalid-token");
         vm.prank(address(0xe0a)); bridge.bridgeERC20(address(0), address(0xbad), 100 ether, 1_000_000, "");
 
+        vm.expectRevert("L2TokenBridge/amount-too-large");
+        vm.prank(address(0xe0a)); bridge.bridgeERC20(address(l2Token), l1Token, 1_000_000 ether + 1, 1_000_000, "");
+
         uint256 supplyBefore = l2Token.totalSupply();
         uint256 eoaBefore = l2Token.balanceOf(address(0xe0a));
         vm.prank(address(0xe0a)); l2Token.approve(address(bridge), type(uint256).max);