[Backport release/v6.x] add bridge update cutoff time

app/upgrades/v6.1.4/upgrade.go

@@ -28,7 +28,7 @@ Upgrade to v6.1.4 includes:
 // TODO: change these to real addresses
 const (
 	MainnetChainID       = "tellor1"
-	MainnetTokenBridgeV2 = "0xa5fE7C1dD35Ce246fdc7FA165A2782049202D3D2"
+	MainnetTokenBridgeV2 = "0x6ec401744008f4B018Ed9A36f76e6629799Ee50E"
 	TestnetChainID       = "layertest-4"
 	TestnetTokenBridgeV2 = "0x55355157703A44f7516FBB831333317E98944e32"
 )

evm/contracts/token-bridge/TokenBridgeV2.sol

@@ -26,6 +26,7 @@ contract TokenBridgeV2 is LayerTransition, RoleManager {
     uint256 public totalPauseTributeBalance; // total amount of tokens held as pause tribute
     uint256 public withdrawLimitUpdateTime; // last time the withdraw limit was updated
     uint256 public withdrawLimitRecord; // amount you can withdraw per limit period
+    uint256 public immutable DATA_BRIDGE_UPDATE_BUFFER; // buffer time at end of pause period when bridge can not longer be updated
     uint256 public constant DEPOSIT_LIMIT_DENOMINATOR = 100e18 / 20e18; // 100/depositLimitPercentage
     uint256 public constant MS_PER_SECOND = 1000; // factor to convert milliseconds to seconds
     uint256 public immutable PAUSE_PERIOD; // bridge pause period duration
@@ -112,6 +113,7 @@ contract TokenBridgeV2 is LayerTransition, RoleManager {
         dataBridge = ITellorDataBridge(_dataBridge);
         deployer = msg.sender;
         PAUSE_PERIOD = _pausePeriod;
+        DATA_BRIDGE_UPDATE_BUFFER = _pausePeriod * 2 / 21;
 
         roles[keccak256("APPROVE_PAUSE")] = RoleInfo({
             roleAddress: _subGuardian,
@@ -251,6 +253,7 @@ contract TokenBridgeV2 is LayerTransition, RoleManager {
     function updateDataBridge(address _dataBridge) external {
         _roleRestricted(keccak256("UPDATE_DATA_BRIDGE"));
         require(bridgeState == BridgeState.PAUSED, "TokenBridgeV2: can only update data bridge when bridge is paused");
+        require(block.timestamp < lastPauseTimestamp + PAUSE_PERIOD - DATA_BRIDGE_UPDATE_BUFFER, "TokenBridgeV2: can only update data bridge before the buffer time");
         require(_dataBridge != address(0), "TokenBridgeV2: data bridge address cannot be the zero address");
         dataBridge = ITellorDataBridge(_dataBridge);
         emit DataBridgeUpdated(_dataBridge);

evm/test/TokenBridgeV2-FunctionTests.js

@@ -69,6 +69,11 @@ describe("TokenBridgeV2 - Function Tests", async function () {
     it("constructor", async function () {
         assert.equal(await tbridge.token(), await token.address)
         assert.equal(await tbridge.dataBridge(), await blobstream.address)
+        assert.equal(
+            (await tbridge.DATA_BRIDGE_UPDATE_BUFFER()).toString(),
+            String((PAUSE_PERIOD * 2) / 21),
+            "DATA_BRIDGE_UPDATE_BUFFER should be 2/21 of pause period"
+        )
         const mainGuardianRole = ethers.utils.keccak256(ethers.utils.toUtf8Bytes("MAIN_GUARDIAN"))
         const approvePauseRole = ethers.utils.keccak256(ethers.utils.toUtf8Bytes("APPROVE_PAUSE"))
         assert.equal((await tbridge.roles(mainGuardianRole)).roleAddress, await mainGuardian.address)
@@ -508,6 +513,32 @@ describe("TokenBridgeV2 - Function Tests", async function () {
         assert.equal(await tbridge.dataBridge(), blobstream2.address)
     })
 
+    it("updateDataBridge reverts after buffer window before pause period ends", async function () {
+        for (let i = 0; i < 10; i++) {
+            await token.faucet(accounts[1].address)
+        }
+        await token.connect(accounts[1]).approve(tbridge.address, h.toWei("10000"))
+        await tbridge.connect(accounts[1]).proposePauseBridge("layer")
+        await tbridge.connect(subGuardian).approvePause(0)
+
+        const lastPause = await tbridge.lastPauseTimestamp()
+        const pausePeriod = await tbridge.PAUSE_PERIOD()
+        const buffer = await tbridge.DATA_BRIDGE_UPDATE_BUFFER()
+        const latest = ethers.BigNumber.from((await ethers.provider.getBlock("latest")).timestamp)
+        const deadline = lastPause.add(pausePeriod).sub(buffer)
+        const advance = deadline.sub(latest)
+        await h.advanceTime(advance.toNumber())
+
+        const blobstream3 = await ethers.deployContract(
+            "TellorDataBridge", [
+            mainGuardian.address,
+            VALIDATOR_SET_DOMAIN_SEPARATOR_MAINNET
+        ]
+        )
+        await blobstream3.init(1, 2, UNBONDING_PERIOD, ethers.utils.solidityKeccak256(["string"], ["buffer-test"]))
+        await h.expectThrow(tbridge.connect(mainGuardian).updateDataBridge(blobstream3.address))
+    })
+
     it("role updates", async function () {
         const MAIN_GUARDIAN_ROLE = ethers.utils.keccak256(ethers.utils.toUtf8Bytes("MAIN_GUARDIAN"))
         const APPROVE_PAUSE_ROLE = ethers.utils.keccak256(ethers.utils.toUtf8Bytes("APPROVE_PAUSE"))