Suggestion 3: Adding missing check for ownership of tBTC token (#415)

Added a missing check for ownership of tBTC token when updating the
tbtcVault address.

solidity/contracts/BitcoinRedeemer.sol

@@ -61,6 +61,9 @@ contract BitcoinRedeemer is Ownable2StepUpgradeable, IReceiveApproval {
     /// Reverts when approveAndCall to tBTC contract fails.
     error ApproveAndCallFailed();
 
+    /// Reverts if the new TBTCVault contract is not tBTC token owner.
+    error NotTbtcTokenOwner();
+
     /// @custom:oz-upgrades-unsafe-allow constructor
     constructor() {
         _disableInitializers();
@@ -118,6 +121,10 @@ contract BitcoinRedeemer is Ownable2StepUpgradeable, IReceiveApproval {
             revert ZeroAddress();
         }
 
+        if (newTbtcVault != tbtcToken.owner()) {
+            revert NotTbtcTokenOwner();
+        }
+
         emit TbtcVaultUpdated(tbtcVault, newTbtcVault);
 
         tbtcVault = newTbtcVault;

solidity/test/BitcoinRedeemer.test.ts

@@ -442,14 +442,24 @@ describe("BitcoinRedeemer", () => {
         })
       })
 
-      context("when a new treasury is an allowed address", () => {
+      context("when a new tbtc vault is not tBTC token owner", () => {
+        it("should revert", async () => {
+          const newTbtcVault = await ethers.Wallet.createRandom().getAddress()
+          await expect(
+            bitcoinRedeemer.connect(governance).updateTbtcVault(newTbtcVault),
+          ).to.be.revertedWithCustomError(bitcoinRedeemer, "NotTbtcTokenOwner")
+        })
+      })
+
+      context("when a new tbtc vault is an allowed address", () => {
         let oldTbtcVault: string
         let newTbtcVault: string
         let tx: ContractTransactionResponse
 
         before(async () => {
           oldTbtcVault = await bitcoinRedeemer.tbtcVault()
           newTbtcVault = await ethers.Wallet.createRandom().getAddress()
+          await tbtc.setOwner(newTbtcVault)
 
           tx = await bitcoinRedeemer
             .connect(governance)