From dfa7033d2e1aa2f2845335d29d6142cc9a7ac5f1 Mon Sep 17 00:00:00 2001
From: Diana Carvalho <diana@propellerheads.xyz>
Date: Tue, 28 Jan 2025 13:03:04 +0000
Subject: [PATCH] feat: Smother slither and add a reentrancy guard in swap()

--- don't change below this line ---
ENG-4041 Took 34 minutes
---
 foundry/src/ExecutionDispatcher.sol         |  5 ++---
 foundry/src/TychoRouter.sol                 | 13 +++++++++----
 foundry/src/executors/UniswapV2Executor.sol |  1 +
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/foundry/src/ExecutionDispatcher.sol b/foundry/src/ExecutionDispatcher.sol
index 8a80d74..e8b36e8 100644
--- a/foundry/src/ExecutionDispatcher.sol
+++ b/foundry/src/ExecutionDispatcher.sol
@@ -50,7 +50,7 @@ contract ExecutionDispatcher {
      * @dev Calls an executor, assumes swap.protocolData contains
      *  protocol-specific data required by the executor.
      */
-    // slither-disable-next-line dead-code
+    // slither-disable-next-line delegatecall-loop
     function _callExecutor(
         address executor,
         bytes4 selector,
@@ -62,8 +62,7 @@ contract ExecutionDispatcher {
         }
 
         selector = selector == bytes4(0) ? IExecutor.swap.selector : selector;
-
-        // slither-disable-next-line low-level-calls
+        // slither-disable-next-line controlled-delegatecall,low-level-calls
         (bool success, bytes memory result) = executor.delegatecall(
             abi.encodeWithSelector(selector, amount, data)
         );
diff --git a/foundry/src/TychoRouter.sol b/foundry/src/TychoRouter.sol
index 880aa77..616d5c0 100644
--- a/foundry/src/TychoRouter.sol
+++ b/foundry/src/TychoRouter.sol
@@ -7,10 +7,11 @@ import "./CallbackVerificationDispatcher.sol";
 import "@openzeppelin/contracts/access/AccessControl.sol";
 import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
+import "@openzeppelin/contracts/utils/Pausable.sol";
 import "@permit2/src/interfaces/IAllowanceTransfer.sol";
 import "./ExecutionDispatcher.sol";
 import "./CallbackVerificationDispatcher.sol";
-import "@openzeppelin/contracts/utils/Pausable.sol";
 import {LibSwap} from "../lib/LibSwap.sol";
 
 error TychoRouter__WithdrawalFailed();
@@ -22,7 +23,8 @@ contract TychoRouter is
     AccessControl,
     ExecutionDispatcher,
     CallbackVerificationDispatcher,
-    Pausable
+    Pausable,
+    ReentrancyGuard
 {
     IAllowanceTransfer public immutable permit2;
     IWETH private immutable _weth;
@@ -125,7 +127,9 @@ contract TychoRouter is
         IAllowanceTransfer.PermitSingle calldata permitSingle,
         bytes calldata signature,
         bytes calldata swaps
-    ) external payable whenNotPaused returns (uint256 amountOut) {
+    ) external payable whenNotPaused nonReentrant returns (uint256 amountOut) {
+        require(receiver != address(0), "Invalid receiver address");
+
         // For native ETH, assume funds already in our router. Else, transfer and handle approval.
         if (wrapEth) {
             _wrapETH(amountIn);
@@ -145,7 +149,7 @@ contract TychoRouter is
             uint256 feeAmount = (amountOut * fee) / 10000;
             amountOut -= feeAmount;
             IERC20(tokenOut).safeTransfer(feeReceiver, feeAmount);
-            if (unwrapEth == false) {
+            if (!unwrapEth) {
                 IERC20(tokenOut).safeTransfer(receiver, amountOut);
             }
         }
@@ -156,6 +160,7 @@ contract TychoRouter is
 
         if (unwrapEth) {
             _unwrapETH(amountOut);
+            // slither-disable-next-line arbitrary-send-eth
             payable(receiver).transfer(amountOut);
         }
     }
diff --git a/foundry/src/executors/UniswapV2Executor.sol b/foundry/src/executors/UniswapV2Executor.sol
index d892122..9f447f1 100644
--- a/foundry/src/executors/UniswapV2Executor.sol
+++ b/foundry/src/executors/UniswapV2Executor.sol
@@ -10,6 +10,7 @@ error UniswapV2Executor__InvalidDataLength();
 contract UniswapV2Executor is IExecutor {
     using SafeERC20 for IERC20;
 
+    // slither-disable-next-line locked-ether
     function swap(uint256 givenAmount, bytes calldata data)
         external
         payable