contracts-bedrock: add unsafe block signer

Added the key responsible for unsafe block distrubtion
to the `SystemConfig` contract. This allows for the `op-node`
to read this value and know what peers to accept unsafe blocks
from.

packages/contracts-bedrock/contracts/L1/SystemConfig.sol

@@ -16,14 +16,17 @@ contract SystemConfig is OwnableUpgradeable, Semver {
     /**
      * @notice Enum representing different types of updates.
      *
-     * @custom:value BATCHER    Represents an update to the batcher hash.
-     * @custom:value GAS_CONFIG Represents an update to txn fee config on L2.
-     * @custom:value GAS_LIMIT  Represents an update to gas limit on L2.
+     * @custom:value BATCHER           Represents an update to the batcher hash.
+     * @custom:value GAS_CONFIG        Represents an update to txn fee config on L2.
+     * @custom:value GAS_LIMIT         Represents an update to gas limit on L2.
+     * @custom:value UNSAFE_BLOCK_KEY  Represents an update to the signer key for unsafe
+     *                                 block distrubution.
      */
     enum UpdateType {
         BATCHER,
         GAS_CONFIG,
-        GAS_LIMIT
+        GAS_LIMIT,
+        UNSAFE_BLOCK_KEY
     }
 
     /**
@@ -54,6 +57,12 @@ contract SystemConfig is OwnableUpgradeable, Semver {
      */
     bytes32 public batcherHash;
 
+    /**
+     * @notice Address corresponding to the key that can propagate unsafe blocks
+     *         across the p2p network.
+     */
+    address public unsafeBlockSigner;
+
     /**
      * @notice L2 gas limit.
      */
@@ -82,9 +91,10 @@ contract SystemConfig is OwnableUpgradeable, Semver {
         uint256 _overhead,
         uint256 _scalar,
         bytes32 _batcherHash,
-        uint64 _gasLimit
+        uint64 _gasLimit,
+        address _unsafeBlockSigner
     ) Semver(1, 0, 0) {
-        initialize(_owner, _overhead, _scalar, _batcherHash, _gasLimit);
+        initialize(_owner, _overhead, _scalar, _batcherHash, _gasLimit, _unsafeBlockSigner);
     }
 
     /**
@@ -101,7 +111,8 @@ contract SystemConfig is OwnableUpgradeable, Semver {
         uint256 _overhead,
         uint256 _scalar,
         bytes32 _batcherHash,
-        uint64 _gasLimit
+        uint64 _gasLimit,
+        address _unsafeBlockSigner
     ) public initializer {
         require(_gasLimit >= MINIMUM_GAS_LIMIT, "SystemConfig: gas limit too low");
         __Ownable_init();
@@ -110,6 +121,7 @@ contract SystemConfig is OwnableUpgradeable, Semver {
         scalar = _scalar;
         batcherHash = _batcherHash;
         gasLimit = _gasLimit;
+        unsafeBlockSigner = _unsafeBlockSigner;
     }
 
     /**
@@ -139,6 +151,13 @@ contract SystemConfig is OwnableUpgradeable, Semver {
         emit ConfigUpdate(VERSION, UpdateType.GAS_CONFIG, data);
     }
 
+    function setUnsafeBlockSigner(address _unsafeBlockSigner) external onlyOwner {
+        unsafeBlockSigner = _unsafeBlockSigner;
+
+        bytes memory data = abi.encode(_unsafeBlockSigner);
+        emit ConfigUpdate(VERSION, UpdateType.UNSAFE_BLOCK_KEY, data);
+    }
+
     /**
      * @notice Updates the L2 gas limit.
      *

packages/contracts-bedrock/contracts/deployment/SystemDictator.sol

@@ -78,6 +78,7 @@ contract SystemDictator is OwnableUpgradeable {
         uint256 scalar;
         bytes32 batcherHash;
         uint64 gasLimit;
+        address unsafeBlockSigner;
     }
 
     /**
@@ -353,7 +354,8 @@ contract SystemDictator is OwnableUpgradeable {
                     config.systemConfigConfig.overhead,
                     config.systemConfigConfig.scalar,
                     config.systemConfigConfig.batcherHash,
-                    config.systemConfigConfig.gasLimit
+                    config.systemConfigConfig.gasLimit,
+                    config.systemConfigConfig.unsafeBlockSigner
                 )
             )
         );

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

@@ -13,7 +13,8 @@ contract SystemConfig_Init is CommonTest {
             _overhead: 2100,
             _scalar: 1000000,
             _batcherHash: bytes32(hex"abcd"),
-            _gasLimit: 9_000_000
+            _gasLimit: 9_000_000,
+            _unsafeBlockSigner: address(1)
         });
     }
 }
@@ -29,7 +30,8 @@ contract SystemConfig_Initialize_TestFail is CommonTest {
             _overhead: 0,
             _scalar: 0,
             _batcherHash: bytes32(hex""),
-            _gasLimit: MINIMUM_GAS_LIMIT - 1
+            _gasLimit: MINIMUM_GAS_LIMIT - 1,
+            _unsafeBlockSigner: address(1)
         });
     }
 }
@@ -49,6 +51,11 @@ contract SystemConfig_Setters_TestFail is SystemConfig_Init {
         vm.expectRevert("Ownable: caller is not the owner");
         sysConf.setGasLimit(0);
     }
+
+    function test_setUnsafeBlockSigner_notOwner_reverts() external {
+        vm.expectRevert("Ownable: caller is not the owner");
+        sysConf.setUnsafeBlockSigner(address(0x20));
+    }
 }
 
 contract SystemConfig_Setters_Test is SystemConfig_Init {
@@ -94,4 +101,17 @@ contract SystemConfig_Setters_Test is SystemConfig_Init {
         sysConf.setGasLimit(newGasLimit);
         assertEq(sysConf.gasLimit(), newGasLimit);
     }
+
+    function testFuzz_setUnsafeBlockSigner_succeeds(address newUnsafeSigner) external {
+        vm.expectEmit(true, true, true, true);
+        emit ConfigUpdate(
+            0,
+            SystemConfig.UpdateType.UNSAFE_BLOCK_KEY,
+            abi.encode(newUnsafeSigner)
+        );
+
+        vm.prank(sysConf.owner());
+        sysConf.setUnsafeBlockSigner(newUnsafeSigner);
+        assertEq(sysConf.unsafeBlockSigner(), newUnsafeSigner);
+    }
 }

packages/contracts-bedrock/deploy/017-SystemConfigImpl.ts

@@ -17,6 +17,7 @@ const deployFn: DeployFunction = async (hre) => {
       hre.deployConfig.gasPriceOracleScalar,
       batcherHash,
       hre.deployConfig.l2GenesisBlockGasLimit,
+      hre.deployConfig.p2pSequencerAddress,
     ],
     postDeployAction: async (contract) => {
       await assertContractVariable(
@@ -35,6 +36,11 @@ const deployFn: DeployFunction = async (hre) => {
         hre.deployConfig.gasPriceOracleScalar
       )
       await assertContractVariable(contract, 'batcherHash', batcherHash)
+      await assertContractVariable(
+        contract,
+        'unsafeBlockSigner',
+        hre.deployConfig.p2pSequencerAddress
+      )
     },
   })
 }

packages/contracts-bedrock/deploy/019-SystemDictatorInit.ts

@@ -99,6 +99,7 @@ const deployFn: DeployFunction = async (hre) => {
         32
       ),
       gasLimit: hre.deployConfig.l2GenesisBlockGasLimit,
+      unsafeBlockSigner: hre.deployConfig.unsafeBlockSigner,
     },
   }