From f69ec1222aaa3e900214ea3da58e12bbe2ae493f Mon Sep 17 00:00:00 2001
From: Alan Donoso Naumczuk <adonoso@itba.edu.ar>
Date: Sun, 29 Dec 2024 15:31:50 -0300
Subject: [PATCH] feat: BaseSource now does source validation using EIP-712

---
 contracts/core/base/BaseSource.sol            | 43 +++++++++++++++----
 .../rules/base/RestrictedSignersRule.sol      | 18 +++++---
 2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/contracts/core/base/BaseSource.sol b/contracts/core/base/BaseSource.sol
index 8b6c16e0..f0b52316 100644
--- a/contracts/core/base/BaseSource.sol
+++ b/contracts/core/base/BaseSource.sol
@@ -6,8 +6,12 @@ import {ISource} from "./../interfaces/ISource.sol";
 import {SourceStamp} from "./../types/Types.sol";
 
 abstract contract BaseSource is ISource {
-    uint256 internal immutable EC_SIGNATURE_LENGTH = 65;
-    bytes2 internal immutable EIP191_VERSION_BYTE_0X00_HEADER = 0x1900;
+    bytes2 internal immutable EIP191_VERSION_BYTE_0X01_HEADER = 0x1901;
+    string constant EIP712_DOMAIN_VERSION = "1";
+    bytes32 constant EIP712_DOMAIN_VERSION_HASH = keccak256(bytes(EIP712_DOMAIN_VERSION));
+    bytes32 constant EIP712_DOMAIN_TYPEHASH =
+        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
+    bytes32 constant SOURCE_STAMP_TYPEHASH = keccak256("SourceStamp(address source,uint256 nonce,uint256 deadline)");
 
     mapping(uint256 => bool) internal _wasSourceStampNonceUsed;
 
@@ -24,13 +28,8 @@ abstract contract BaseSource is ISource {
         require(!_wasSourceStampNonceUsed[sourceStamp.nonce]);
         require(sourceStamp.deadline >= block.timestamp);
         require(sourceStamp.source == address(this));
-        require(sourceStamp.signature.length == EC_SIGNATURE_LENGTH);
         _wasSourceStampNonceUsed[sourceStamp.nonce] = true;
-        bytes32 sourceStampHash = keccak256(
-            abi.encodePacked(
-                EIP191_VERSION_BYTE_0X00_HEADER, sourceStamp.source, sourceStamp.nonce, sourceStamp.deadline
-            )
-        );
+        bytes32 digest = _calculateDigest(_calculateHashStruct(sourceStamp));
         bytes32 r;
         bytes32 s;
         uint8 v;
@@ -40,11 +39,37 @@ abstract contract BaseSource is ISource {
             s := mload(add(signature, 0x40))
             v := byte(0, mload(add(signature, 0x60)))
         }
-        address signer = ecrecover(sourceStampHash, v, r, s);
+        address signer = ecrecover(digest, v, r, s);
         require(_isValidSourceStampSigner(signer));
     }
 
     function _isValidSourceStampSigner(
         address signer
     ) internal virtual returns (bool);
+
+    function _calculateHashStruct(
+        SourceStamp memory sourceStamp
+    ) private pure returns (bytes32) {
+        return keccak256(abi.encode(SOURCE_STAMP_TYPEHASH, sourceStamp.source, sourceStamp.nonce, sourceStamp.deadline));
+    }
+
+    function _calculateDigest(
+        bytes32 hashStruct
+    ) private view returns (bytes32) {
+        return keccak256(
+            abi.encodePacked(EIP191_VERSION_BYTE_0X01_HEADER, _calculateDomainSeparatorHashStruct(), hashStruct)
+        );
+    }
+
+    function _calculateDomainSeparatorHashStruct() private view returns (bytes32) {
+        return keccak256(
+            abi.encode(
+                EIP712_DOMAIN_TYPEHASH,
+                keccak256("Lens Source"),
+                EIP712_DOMAIN_VERSION_HASH,
+                block.chainid,
+                address(this)
+            )
+        );
+    }
 }
diff --git a/contracts/rules/base/RestrictedSignersRule.sol b/contracts/rules/base/RestrictedSignersRule.sol
index c868dae7..62881477 100644
--- a/contracts/rules/base/RestrictedSignersRule.sol
+++ b/contracts/rules/base/RestrictedSignersRule.sol
@@ -67,11 +67,15 @@ abstract contract RestrictedSignersRule is MetadataBased {
         "RestrictedSignerMessage(bytes4 functionSelector,bytes abiEncodedParams,uint256 nonce,uint256 deadline)"
     );
 
-    constructor(string memory metadataURI) {
+    constructor(
+        string memory metadataURI
+    ) {
         _setMetadataURI(metadataURI);
     }
 
-    function _emitMetadataURISet(string memory metadataURI) internal override {
+    function _emitMetadataURISet(
+        string memory metadataURI
+    ) internal override {
         emit Lens_Rule_MetadataURISet(metadataURI);
     }
 
@@ -125,7 +129,9 @@ abstract contract RestrictedSignersRule is MetadataBased {
         _validateRecoveredAddress(digest, signature);
     }
 
-    function _calculateMessageHashStruct(RestrictedSignerMessage memory message) private pure returns (bytes32) {
+    function _calculateMessageHashStruct(
+        RestrictedSignerMessage memory message
+    ) private pure returns (bytes32) {
         return keccak256(
             abi.encode(
                 RESTRICTED_SIGNER_MESSAGE_TYPEHASH,
@@ -137,7 +143,9 @@ abstract contract RestrictedSignersRule is MetadataBased {
         );
     }
 
-    function _calculateDigest(bytes32 messageHashStruct) private view returns (bytes32) {
+    function _calculateDigest(
+        bytes32 messageHashStruct
+    ) private view returns (bytes32) {
         return keccak256(abi.encodePacked("\x19\x01", _calculateDomainSeparatorHashStruct(), messageHashStruct));
     }
 
@@ -148,7 +156,7 @@ abstract contract RestrictedSignersRule is MetadataBased {
                 keccak256("Lens Protocol Restricted Signer Rule"),
                 EIP712_DOMAIN_VERSION_HASH,
                 block.chainid,
-                msg.sender // This is the address of the primitive, and we assume the primitive calls the rule
+                msg.sender // TODO: This is using primitive's address, maybe should be address(this), so it's rule addr
             )
         );
     }