Add an updated EIP-1271 function to the WebAuthn signer

modules/4337/contracts/experimental/SafeSignerLaunchpad.sol

@@ -4,8 +4,8 @@ pragma solidity >=0.8.0 <0.9.0;
 import {IAccount} from "@account-abstraction/contracts/interfaces/IAccount.sol";
 import {UserOperation} from "@account-abstraction/contracts/interfaces/UserOperation.sol";
 import {_packValidationData} from "@account-abstraction/contracts/core/Helpers.sol";
-import {ISignatureValidator} from "@safe-global/safe-contracts/contracts/interfaces/ISignatureValidator.sol";
 import {SafeStorage} from "@safe-global/safe-contracts/contracts/libraries/SafeStorage.sol";
+import {SignatureValidatorConstants} from "./SignatureValidatorConstants.sol";
 
 interface IUniqueSignerFactory {
     /**
@@ -31,7 +31,7 @@ interface IUniqueSignerFactory {
      * @param data The data whose signature should be verified.
      * @param signature The signature bytes.
      * @param signerData The signer data to verify signature for.
-     * @return magicValue Returns `ISignatureValidator.isValidSignature.selector` when the signature is valid. Reverting or returning any other value implies an invalid signature.
+     * @return magicValue Returns a legacy EIP-1271 magic value (`keccak256(isValidSignature(bytes,bytes)`) when the signature is valid. Reverting or returning any other value implies an invalid signature.
      */
     function isValidSignatureForSigner(
         bytes calldata data,
@@ -44,7 +44,7 @@ interface IUniqueSignerFactory {
  * @title SafeOpLaunchpad - A contract for Safe initialization with custom unique signers that would violate ERC-4337 factory rules.
  * @dev The is intended to be set as a Safe proxy's implementation for ERC-4337 user operation that deploys the account.
  */
-contract SafeSignerLaunchpad is IAccount, SafeStorage {
+contract SafeSignerLaunchpad is IAccount, SafeStorage, SignatureValidatorConstants {
     bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = keccak256("EIP712Domain(uint256 chainId,address verifyingContract)");
 
     // keccak256("SafeSignerLaunchpad.initHash") - 1
@@ -171,7 +171,7 @@ contract SafeSignerLaunchpad is IAccount, SafeStorage {
 
         bytes memory operationData = _getOperationData(userOpHash, validAfter, validUntil);
         bytes4 magicValue = IUniqueSignerFactory(signerFactory).isValidSignatureForSigner(operationData, signature, signerData);
-        validationData = _packValidationData(magicValue != ISignatureValidator.isValidSignature.selector, validUntil, validAfter);
+        validationData = _packValidationData(magicValue != LEGACY_EIP1271_MAGIC_VALUE, validUntil, validAfter);
 
         if (missingAccountFunds > 0) {
             // solhint-disable-next-line no-inline-assembly

modules/4337/contracts/experimental/SignatureValidatorConstants.sol

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: LGPL-3.0-only
+/* solhint-disable one-contract-per-file */
+pragma solidity >=0.7.0 <0.9.0;
+
+/**
+ * @title SignatureValidatorConstants
+ * @dev This contract defines the constants used for EIP-1271 signature validation.
+ */
+contract SignatureValidatorConstants {
+  // bytes4(keccak256("isValidSignature(bytes32,bytes)")
+  bytes4 internal constant EIP1271_MAGIC_VALUE = 0x1626ba7e;
+
+  // bytes4(keccak256("isValidSignature(bytes,bytes)")
+  bytes4 internal constant LEGACY_EIP1271_MAGIC_VALUE = 0x20c13b0b;
+}

modules/4337/contracts/experimental/WebAuthnSigner.sol

@@ -3,6 +3,7 @@
 pragma solidity >=0.8.0;
 
 import {FCL_WebAuthn} from "../vendor/FCL/FCL_Webauthn.sol";
+import {SignatureValidatorConstants} from "./SignatureValidatorConstants.sol";
 import {IUniqueSignerFactory} from "./SafeSignerLaunchpad.sol";
 
 struct SignatureData {
@@ -12,14 +13,14 @@ struct SignatureData {
     uint256[2] rs;
 }
 
-function checkSignature(bytes memory data, bytes calldata signature, uint256 x, uint256 y) view returns (bytes4 magicValue) {
+function checkSignature(bytes memory data, bytes calldata signature, uint256 x, uint256 y) view returns (bool valid) {
     SignatureData calldata signaturePointer;
     // solhint-disable-next-line no-inline-assembly
     assembly ("memory-safe") {
         signaturePointer := signature.offset
     }
 
-    if (
+    return
         FCL_WebAuthn.checkSignature(
             signaturePointer.authenticatorData,
             0x01, // require user presence
@@ -29,17 +30,14 @@ function checkSignature(bytes memory data, bytes calldata signature, uint256 x,
             signaturePointer.rs,
             x,
             y
-        )
-    ) {
-        magicValue = WebAuthnSigner.isValidSignature.selector;
-    }
+        );
 }
 
 /**
  * @title WebAuthnSigner
  * @dev A contract that represents a WebAuthn signer.
  */
-contract WebAuthnSigner {
+contract WebAuthnSigner is SignatureValidatorConstants {
     uint256 public immutable X;
     uint256 public immutable Y;
 
@@ -60,15 +58,29 @@ contract WebAuthnSigner {
      * @return magicValue The magic value indicating the validity of the signature.
      */
     function isValidSignature(bytes memory data, bytes calldata signature) external view returns (bytes4 magicValue) {
-        return checkSignature(data, signature, X, Y);
+        if (checkSignature(data, signature, X, Y)) {
+            magicValue = LEGACY_EIP1271_MAGIC_VALUE;
+        }
+    }
+
+    /**
+     * @dev Validates the signature for a given data hash.
+     * @param dataHash The hash of the data to be validated.
+     * @param signature The signature to be validated.
+     * @return magicValue The magic value indicating the validity of the signature.
+     */
+    function isValidSignature(bytes32 dataHash, bytes calldata signature) external view returns (bytes4 magicValue) {
+        if (checkSignature(abi.encode(dataHash), signature, X, Y)) {
+            magicValue = EIP1271_MAGIC_VALUE;
+        }
     }
 }
 
 /**
  * @title WebAuthnSignerFactory
  * @dev A factory contract for creating and managing WebAuthn signers.
  */
-contract WebAuthnSignerFactory is IUniqueSignerFactory {
+contract WebAuthnSignerFactory is IUniqueSignerFactory, SignatureValidatorConstants {
     /**
      * @dev Retrieves the signer address based on the provided data.
      * @param data Concatenated X and Y coordinates of the signer as bytes.
@@ -106,7 +118,9 @@ contract WebAuthnSignerFactory is IUniqueSignerFactory {
         bytes calldata signerData
     ) external view override returns (bytes4 magicValue) {
         (uint256 x, uint256 y) = abi.decode(signerData, (uint256, uint256));
-        magicValue = checkSignature(data, signature, x, y);
+        if(checkSignature(data, signature, x, y)) {
+            magicValue = LEGACY_EIP1271_MAGIC_VALUE;
+        }
     }
 
     /**