Add E2E Test with WebAuthn Signer (#197)

A huge part of the way to #173

This PR adds an E2E test using the reference 4337 EntryPoint and bundler
for a Safe deployment with a WebAuthn (i.e. Passkeys) signer.

Note that this E2E test is not 100% complete. In particular, we don't
get test using the Safe after the launchpad deployment is completed. I
want to add that test in a follow-up when I actually add the gas
profiling for the WebAuthn signer.

4337/.solcover.js

@@ -1,14 +1,5 @@
-const fs = require('fs')
-const path = require('path')
-
-const testDir = path.join(__dirname, 'contracts', 'test')
-const testContracts = fs
-  .readdirSync(testDir)
-  .filter((file) => file.endsWith('.sol'))
-  .map((file) => path.join('test', file))
-
 module.exports = {
-  skipFiles: testContracts,
+  skipFiles: ['test'],
   mocha: {
     grep: '@skip-on-coverage', // Find everything with this tag
     invert: true, // Run the grep's inverse set.

4337/contracts/test/SafeMock.sol

@@ -25,7 +25,7 @@ contract SafeMock {
 
     function _signatureSplit(bytes memory signature) internal pure returns (uint8 v, bytes32 r, bytes32 s) {
         // solhint-disable-next-line no-inline-assembly
-        assembly {
+        assembly ("memory-safe") {
             r := mload(add(signature, 0x20))
             s := mload(add(signature, 0x40))
             v := byte(0, mload(add(signature, 0x60)))

4337/contracts/test/SafeSignerLaunchpad.sol

@@ -242,12 +242,10 @@ contract SafeSignerLaunchpad is IAccount, SafeStorage {
 
     function _isContract(address account) internal view returns (bool) {
         uint256 size;
-        /* solhint-disable no-inline-assembly */
-        /// @solidity memory-safe-assembly
-        assembly {
+        // solhint-disable-next-line no-inline-assembly
+        assembly ("memory-safe") {
             size := extcodesize(account)
         }
-        /* solhint-enable no-inline-assembly */
         return size > 0;
     }
 }

4337/contracts/test/TestEntryPoint.sol

@@ -20,8 +20,8 @@ contract SenderCreator {
         address factory = address(bytes20(initCode[0:20]));
         bytes memory initCallData = initCode[20:];
         bool success;
-        /* solhint-disable no-inline-assembly */
-        assembly {
+        // solhint-disable-next-line no-inline-assembly
+        assembly ("memory-safe") {
             success := call(gas(), factory, 0, add(initCallData, 0x20), mload(initCallData), 0, 32)
             sender := mload(0)
         }

4337/contracts/test/TestUniqueSigner.sol

@@ -59,12 +59,10 @@ contract TestUniqueSignerFactory is IUniqueSignerFactory {
 
     function _hasNoCode(address account) internal view returns (bool) {
         uint256 size;
-        /* solhint-disable no-inline-assembly */
-        /// @solidity memory-safe-assembly
-        assembly {
+        // solhint-disable-next-line no-inline-assembly
+        assembly ("memory-safe") {
             size := extcodesize(account)
         }
-        /* solhint-enable no-inline-assembly */
         return size == 0;
     }
 }

4337/contracts/test/WebAuthnSigner.sol

@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+/* solhint-disable one-contract-per-file */
+pragma solidity >=0.8.0;
+
+import {FCL_WebAuthn} from "./FCL/FCL_Webauthn.sol";
+import {IUniqueSignerFactory} from "./SafeSignerLaunchpad.sol";
+
+struct SignatureData {
+    bytes authenticatorData;
+    bytes clientData;
+    uint256 challengeOffset;
+    uint256[2] rs;
+}
+
+function checkSignature(bytes memory data, bytes calldata signature, uint256 x, uint256 y) view returns (bytes4 magicValue) {
+    SignatureData calldata signaturePointer;
+    // solhint-disable-next-line no-inline-assembly
+    assembly ("memory-safe") {
+        signaturePointer := signature.offset
+    }
+
+    if (
+        FCL_WebAuthn.checkSignature(
+            signaturePointer.authenticatorData,
+            0x01, // require user presence
+            signaturePointer.clientData,
+            keccak256(data),
+            signaturePointer.challengeOffset,
+            signaturePointer.rs,
+            x,
+            y
+        )
+    ) {
+        magicValue = WebAuthnSigner.isValidSignature.selector;
+    }
+}
+
+contract WebAuthnSigner {
+    uint256 public immutable X;
+    uint256 public immutable Y;
+
+    constructor(uint256 x, uint256 y) {
+        X = x;
+        Y = y;
+    }
+
+    function isValidSignature(bytes memory data, bytes calldata signature) external view returns (bytes4 magicValue) {
+        return checkSignature(data, signature, X, Y);
+    }
+}
+
+contract WebAuthnSignerFactory is IUniqueSignerFactory {
+    function getSigner(bytes calldata data) public view returns (address signer) {
+        (uint256 x, uint256 y) = abi.decode(data, (uint256, uint256));
+        signer = _getSigner(x, y);
+    }
+
+    function createSigner(bytes calldata data) external returns (address signer) {
+        (uint256 x, uint256 y) = abi.decode(data, (uint256, uint256));
+        signer = _getSigner(x, y);
+        if (_hasNoCode(signer)) {
+            WebAuthnSigner created = new WebAuthnSigner{salt: bytes32(0)}(x, y);
+            require(address(created) == signer);
+        }
+    }
+
+    function isValidSignatureForSigner(
+        bytes memory data,
+        bytes calldata signature,
+        bytes calldata signerData
+    ) external view override returns (bytes4 magicValue) {
+        (uint256 x, uint256 y) = abi.decode(signerData, (uint256, uint256));
+        magicValue = checkSignature(data, signature, x, y);
+    }
+
+    function _getSigner(uint256 x, uint256 y) internal view returns (address) {
+        bytes32 codeHash = keccak256(abi.encodePacked(type(WebAuthnSigner).creationCode, x, y));
+        return address(uint160(uint256(keccak256(abi.encodePacked(hex"ff", address(this), bytes32(0), codeHash)))));
+    }
+
+    function _hasNoCode(address account) internal view returns (bool) {
+        uint256 size;
+        // solhint-disable-next-line no-inline-assembly
+        assembly ("memory-safe") {
+            size := extcodesize(account)
+        }
+        return size == 0;
+    }
+}