From d699a74527d718adbb532daecafacc8530aacf48 Mon Sep 17 00:00:00 2001
From: Sahil Vasava <sahilvasava@gmail.com>
Date: Thu, 15 Feb 2024 17:50:53 +0700
Subject: [PATCH] feat: added WebAuthnSigner for ModularPermissionValidator

---
 .gitignore                                    |  1 +
 .gitmodules                                   |  3 +
 lib/p256-verifier                             |  1 +
 .../signers/WebAuthnSigner.sol                | 82 +++++++++++++++++++
 4 files changed, 87 insertions(+)
 create mode 160000 lib/p256-verifier
 create mode 100644 src/validator/modularPermission/signers/WebAuthnSigner.sol

diff --git a/.gitignore b/.gitignore
index 3978feff..cfe668b2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,3 +32,4 @@ artifacts-selected
 cache_hardhat
 
 lcov.info
+settings.json
\ No newline at end of file
diff --git a/.gitmodules b/.gitmodules
index 744ac54b..467f62e8 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "lib/I4337"]
 	path = lib/I4337
 	url = https://github.com/leekt/I4337
+[submodule "lib/p256-verifier"]
+	path = lib/p256-verifier
+	url = https://github.com/daimo-eth/p256-verifier
diff --git a/lib/p256-verifier b/lib/p256-verifier
new file mode 160000
index 00000000..29475ae3
--- /dev/null
+++ b/lib/p256-verifier
@@ -0,0 +1 @@
+Subproject commit 29475ae300ec95d98d5c7cc34c094846f0aa2dcd
diff --git a/src/validator/modularPermission/signers/WebAuthnSigner.sol b/src/validator/modularPermission/signers/WebAuthnSigner.sol
new file mode 100644
index 00000000..011088fe
--- /dev/null
+++ b/src/validator/modularPermission/signers/WebAuthnSigner.sol
@@ -0,0 +1,82 @@
+pragma solidity ^0.8.0;
+
+import {WebAuthn} from "p256-verifier/WebAuthn.sol";
+import {ISigner} from "../ISigner.sol";
+import {ValidationData} from "../../../common/Types.sol";
+import {SIG_VALIDATION_FAILED} from "../../../common/Constants.sol";
+
+struct WebAuthnValidatorData {
+    uint256 x;
+    uint256 y;
+}
+
+contract WebAuthnSigner is ISigner {
+    mapping(address caller => mapping(bytes32 permissionId => mapping(address kernel => WebAuthnValidatorData))) public
+        webAuthnValidatorStorage;
+
+    function registerSigner(address kernel, bytes32 permissionId, bytes calldata data) external payable override {
+        WebAuthnValidatorData memory pubKey = abi.decode(data, (WebAuthnValidatorData));
+        require(
+            webAuthnValidatorStorage[msg.sender][permissionId][kernel].x == 0
+                && webAuthnValidatorStorage[msg.sender][permissionId][kernel].y == 0,
+            "WebAuthnSigner: kernel already registered"
+        );
+        require(pubKey.x != 0 && pubKey.y != 0, "WebAuthnSigner: invalid public key");
+        webAuthnValidatorStorage[msg.sender][permissionId][kernel] = pubKey;
+    }
+
+    function validateUserOp(address kernel, bytes32 permissionId, bytes32 userOpHash, bytes calldata signature)
+        external
+        payable
+        override
+        returns (ValidationData)
+    {
+        return _verifySignature(kernel, permissionId, userOpHash, signature);
+    }
+
+    function validateSignature(address kernel, bytes32 permissionId, bytes32 messageHash, bytes calldata signature)
+        external
+        view
+        override
+        returns (ValidationData)
+    {
+        return _verifySignature(kernel, permissionId, messageHash, signature);
+    }
+
+    function _verifySignature(address sender, bytes32 permissionId, bytes32 hash, bytes calldata signature)
+        private
+        view
+        returns (ValidationData)
+    {
+        (
+            bytes memory authenticatorData,
+            string memory clientDataJSON,
+            uint256 challengeLocation,
+            uint256 responseTypeLocation,
+            uint256 r,
+            uint256 s
+        ) = abi.decode(signature, (bytes, string, uint256, uint256, uint256, uint256));
+
+        WebAuthnValidatorData memory pubKey = webAuthnValidatorStorage[msg.sender][permissionId][sender];
+        require(pubKey.x != 0 && pubKey.y != 0, "WebAuthnSigner: kernel not registered");
+
+        bool isValid = WebAuthn.verifySignature(
+            abi.encodePacked(hash),
+            authenticatorData,
+            true, // TODO: check if this needs to be true always
+            clientDataJSON,
+            challengeLocation,
+            responseTypeLocation,
+            r,
+            s,
+            pubKey.x,
+            pubKey.y
+        );
+
+        if (isValid) {
+            return ValidationData.wrap(0);
+        }
+
+        return SIG_VALIDATION_FAILED;
+    }
+}