fix: add check to ensure depositor is a valid EVM address

contracts/SpokePool.sol

@@ -1307,6 +1307,9 @@ abstract contract SpokePool is
      **************************************/
 
     function _depositV3(DepositV3Params memory params) internal {
+        // Verify depositor is a valid EVM address.
+        params.depositor.checkAddress();
+
         // Check that deposit route is enabled for the input token. There are no checks required for the output token
         // which is pulled from the relayer at fill time and passed through this contract atomically to the recipient.
         if (!enabledDepositRoutes[params.inputToken.toAddress()][params.destinationChainId]) revert DisabledRoute();

contracts/libraries/AddressConverters.sol

@@ -8,15 +8,19 @@ library Bytes32ToAddress {
     error InvalidBytes32();
 
     function toAddress(bytes32 _bytes32) internal pure returns (address) {
-        if (uint256(_bytes32) >> 160 != 0) {
-            revert InvalidBytes32();
-        }
+        checkAddress(_bytes32);
         return address(uint160(uint256(_bytes32)));
     }
 
     function toAddressUnchecked(bytes32 _bytes32) internal pure returns (address) {
         return address(uint160(uint256(_bytes32)));
     }
+
+    function checkAddress(bytes32 _bytes32) internal pure {
+        if (uint256(_bytes32) >> 160 != 0) {
+            revert InvalidBytes32();
+        }
+    }
 }
 
 library AddressToBytes32 {

test/evm/hardhat/SpokePool.Deposit.ts

@@ -853,6 +853,15 @@ describe("SpokePool Depositor Logic", async function () {
       const functionCalldata = spokePool.interface.encodeFunctionData("deposit", [...depositArgs]);
       await expect(spokePool.connect(depositor).callback(functionCalldata)).to.be.reverted;
     });
+    it("depositor must be valid evm address", async function () {
+      const functionCalldata = spokePool.interface.encodeFunctionData("deposit", [
+        ...getDepositArgsFromRelayData({
+          ...relayData,
+          depositor: "0x044852b2a670ade5407e78fb2863c51de9fcb96542a07186fe3aeda6bb8a116d",
+        }),
+      ]);
+      await expect(spokePool.connect(depositor).callback(functionCalldata)).to.be.reverted;
+    });
     it("unsafe deposit ID", async function () {
       // new deposit ID should be the uint256 equivalent of the keccak256 hash of packed {msg.sender, depositor, forcedDepositId}.
       const forcedDepositId = "99";