Create a guard that allows trading any token (#261)

- Create very dangerous "whitelist any token policy" for prototype strategies

contracts/guard/src/GuardV0Base.sol

@@ -15,6 +15,8 @@ import "./IGuard.sol";
  *
  * - Abstract base contract to deal with different ownership modifiers and initialisers (Safe, OpenZeppelin)
  *
+ * TODO: Externally managed safe token registry
+ *
  */
 abstract contract GuardV0Base is IGuard  {
     using Path for bytes;
@@ -56,7 +58,7 @@ abstract contract GuardV0Base is IGuard  {
         uint256 amountInMaximum;
     }
 
-    // Allowed ERC20.approve()
+    // Allowed external smart contract calls (address, function selector) tuples
     mapping(address target => mapping(bytes4 selector => bool allowed)) public allowedCallSites;
 
     // How many call sites we have enabled all-time counter.
@@ -83,6 +85,12 @@ abstract contract GuardV0Base is IGuard  {
     // Allowed routers
     mapping(address destination => bool allowed) public allowedDelegationApprovalDestinations;
 
+    // Allow trading any token
+    //
+    // Dangerous, as malicious/compromised trade-executor can drain all assets through creating fake tokens
+    //
+    bool public anyAsset;
+
     event CallSiteApproved(address target, bytes4 selector, string notes);
     event CallSiteRemoved(address target, bytes4 selector, string notes);
 
@@ -104,10 +112,17 @@ abstract contract GuardV0Base is IGuard  {
     event AssetApproved(address sender, string notes);
     event AssetRemoved(address sender, string notes);
 
+    event AnyAssetSet(bool value, string notes);
+
+    // Implementation needs to provide its own ownership policy hooks
     modifier onlyGuardOwner() virtual;
 
+    // Implementation needs to provide its own ownership policy hooks
     function getGovernanceAddress() virtual public view returns (address);
 
+    /**
+     * Calculate Solidity 4-byte function selector from a string.
+     */
     function getSelector(string memory _func) internal pure returns (bytes4) {
         // https://solidity-by-example.org/function-selector/
         return bytes4(keccak256(bytes(_func)));
@@ -195,6 +210,15 @@ abstract contract GuardV0Base is IGuard  {
 
     // Basic check if any target contract is whitelisted
     function isAllowedCallSite(address target, bytes4 selector) public view returns (bool) {
+
+        // If we have dynamic whitelist/any token, we cannot check approve() call sites of
+        // individual tokens
+        if(anyAsset) {
+            if(selector == getSelector("approve(address,uint256)")) {
+                return true;
+            }
+        }
+
         return allowedCallSites[target][selector];
     }
 
@@ -219,8 +243,11 @@ abstract contract GuardV0Base is IGuard  {
         return allowedDelegationApprovalDestinations[receiver] == true;
     }
 
+    /**
+     * Are we allowed to trade/own an ERC-20.
+     */
     function isAllowedAsset(address token) public view returns (bool) {
-        return allowedAssets[token] == true;
+        return anyAsset || allowedAssets[token] == true;
     }
 
     function validate_transfer(bytes memory callData) public view {
@@ -249,6 +276,23 @@ abstract contract GuardV0Base is IGuard  {
         allowAsset(token, notes);
     }
 
+    function whitelistUniswapV3Router(address router, string calldata notes) external {
+        allowCallSite(router, getSelector("exactInput((bytes,address,uint256,uint256,uint256))"), notes);
+        allowCallSite(router, getSelector("exactOutput((bytes,address,uint256,uint256,uint256))"), notes);
+        allowApprovalDestination(router, notes);
+    }
+
+    function whitelistUniswapV2Router(address router, string calldata notes) external {
+        allowCallSite(router, getSelector("swapExactTokensForTokens(uint256,uint256,address[],address,uint256)"), notes);
+        allowApprovalDestination(router, notes);
+    }
+
+    // Enable unlimited trading space
+    function setAnyAssetAllowed(bool value, string calldata notes) external onlyGuardOwner {
+        anyAsset = value;
+        emit AnyAssetSet(value, notes);
+    }
+
     // Satisfy IGuard
     function validateCall(
         address sender,
@@ -311,11 +355,6 @@ abstract contract GuardV0Base is IGuard  {
         }        
     }
 
-    function whitelistUniswapV2Router(address router, string calldata notes) external {
-        allowCallSite(router, getSelector("swapExactTokensForTokens(uint256,uint256,address[],address,uint256)"), notes);
-        allowApprovalDestination(router, notes);
-    }
-
     // validate Uniswap v3 trade
     function validate_exactInput(bytes memory callData) public view {
         (ExactInputParams memory params) = abi.decode(callData, (ExactInputParams));
@@ -349,12 +388,6 @@ abstract contract GuardV0Base is IGuard  {
         }
     }
 
-    function whitelistUniswapV3Router(address router, string calldata notes) external {
-        allowCallSite(router, getSelector("exactInput((bytes,address,uint256,uint256,uint256))"), notes);
-        allowCallSite(router, getSelector("exactOutput((bytes,address,uint256,uint256,uint256))"), notes);
-        allowApprovalDestination(router, notes);
-    }
-
     // validate 1delta trade
     function validate_1deltaMulticall(bytes memory callData) public view {
         (bytes[] memory callArr) = abi.decode(callData, (bytes[]));

tests/guard/test_guard_simple_vault_uniswap_v2.py

@@ -266,7 +266,6 @@ def test_guard_token_in_not_approved(
         target, call_data = encode_simple_vault_transaction(trade_call)
         vault.functions.performCall(target, call_data).transact({"from": asset_manager})
 
-
 def test_guard_token_in_not_approved(
     uniswap_v2: UniswapV2Deployment,
     weth_usdc_pair: PairDetails,
@@ -458,3 +457,76 @@ def test_guard_third_party_trade(
     with pytest.raises(TransactionFailed, match="Sender not allowed"):
         target, call_data = encode_simple_vault_transaction(trade_call)
         vault.functions.performCall(target, call_data).transact({"from": third_party})
+
+
+def test_guard_can_trade_any_asset_uniswap_v2(
+    web3: Web3,
+    uniswap_v2: UniswapV2Deployment,
+    weth_usdc_pair: PairDetails,
+    owner: str,
+    asset_manager: str,
+    deployer: str,
+    weth: Contract,
+    usdc: Contract,
+):
+    """After whitelist removed, we can trade any asset."""
+    weth = uniswap_v2.weth
+    vault = deploy_contract(web3, "guard/SimpleVaultV0.json", deployer, asset_manager)
+    vault.functions.initialiseOwnership(owner).transact({"from": deployer})
+
+    guard = get_deployed_contract(web3, "guard/GuardV0.json", vault.functions.guard().call())
+    guard.functions.whitelistUniswapV2Router(uniswap_v2.router.address, "Allow Uniswap v2").transact({"from": owner})
+    guard.functions.setAnyAssetAllowed(True, "Allow any asset").transact({"from": owner})
+
+    usdc_amount = 10_000 * 10**6
+    usdc.functions.transfer(vault.address, usdc_amount).transact({"from": deployer})
+
+    path = [usdc.address, weth.address]
+
+    #
+    # Buy WETH
+    #
+
+    approve_call = usdc.functions.approve(
+        uniswap_v2.router.address,
+        usdc_amount,
+    )
+
+    target, call_data = encode_simple_vault_transaction(approve_call)
+    vault.functions.performCall(target, call_data).transact({"from": asset_manager})
+
+    trade_call = uniswap_v2.router.functions.swapExactTokensForTokens(
+        usdc_amount,
+        0,
+        path,
+        vault.address,
+        FOREVER_DEADLINE,
+    )
+
+    target, call_data = encode_simple_vault_transaction(trade_call)
+    vault.functions.performCall(target, call_data).transact({"from": asset_manager})
+
+    weth_amount = 3696700037078235076
+    assert weth.functions.balanceOf(vault.address).call() == weth_amount
+
+    #
+    # Sell it back
+    #
+
+    approve_call = weth.functions.approve(
+        uniswap_v2.router.address,
+        weth_amount,
+    )
+    target, call_data = encode_simple_vault_transaction(approve_call)
+    vault.functions.performCall(target, call_data).transact({"from": asset_manager})
+
+    trade_call = uniswap_v2.router.functions.swapExactTokensForTokens(
+        weth_amount,
+        0,
+        [weth.address, usdc.address],
+        vault.address,
+        FOREVER_DEADLINE,
+    )
+
+    target, call_data = encode_simple_vault_transaction(trade_call)
+    vault.functions.performCall(target, call_data).transact({"from": asset_manager})