Merge pull request #85 from getwax/68-calldata-decode-stack-limit

Use original library function (calldata params)
getwax · Sep 15, 2023 · 4085e2c · 4085e2c
2 parents d2cfd8f + eb8f46d
commit 4085e2c
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Showing 4 changed files with 89 additions and 26 deletions.
diff --git a/account-integrations/safe/src/SafeWebAuthnPlugin.sol b/account-integrations/safe/src/SafeWebAuthnPlugin.sol
@@ -67,35 +67,92 @@ contract SafeWebAuthnPlugin is BaseAccount {
         return _publicKey;
     }
 
+    struct LocalVarStruct {
+        bytes1 authenticatorDataFlagMask;
+        uint256 clientChallengeDataOffset;
+    }
+
     function _validateSignature(
         UserOperation calldata userOp,
         bytes32 userOpHash
     ) internal override returns (uint256 validationData) {
-        {
+        bytes calldata authenticatorData;
+        bytes calldata clientData;
+        uint256[2] calldata signature;
+        uint256[2] calldata pubKey;
+        LocalVarStruct memory s;
+
+        {            
+            // parse length of all fixed-length params (including length)
+            uint i = 0;
+            uint dataLen = 32;
+            uint256 paramLen = abi.decode(userOp.signature[i:i+dataLen], (uint256));
+            // Fixed-length params (bytes1, (uint256?), uint256, uint256[2], uint256[2]). Expect 8 slots = 256 bytes
+            i += dataLen; // advance index
+
+            // decode fixed length params (values to memory)
+            dataLen = 3 * 32; //lenFixedParams - 32; // -32 already read length
             (
-                bytes memory authenticatorData,
-                bytes1 authenticatorDataFlagMask,
-                bytes memory clientData,
-                uint256 clientChallengeDataOffset,
-                uint256[2] memory signature,
-                uint256[2] memory pubKey
+                s.authenticatorDataFlagMask,
+                , // some number
+                s.clientChallengeDataOffset
             ) = abi.decode(
-                    userOp.signature,
-                    (bytes, bytes1, bytes, uint256, uint256[2], uint256[2])
-                );
-
-            bool verified = FCL_WebAuthn.checkSignature(
-                authenticatorData,
-                authenticatorDataFlagMask,
-                clientData,
-                userOpHash,
-                clientChallengeDataOffset,
-                signature,
-                pubKey
+                userOp.signature[i:i+dataLen],
+                (
+                    bytes1,
+                    uint256, //not sure what is encoded here
+                    uint256
+                )
             );
-            if (!verified) return SIG_VALIDATION_FAILED;
-            return 0;
+            i += dataLen; // advance index
+
+
+            bytes calldata calldataLocation;
+            // load fixed length array params (pointers to calldata)
+            dataLen = 2 * 32;
+            calldataLocation = userOp.signature[i:i+dataLen];
+            assembly{
+                signature := calldataLocation.offset
+            }
+            i += dataLen; // advance index
+
+            calldataLocation = userOp.signature[i:i+dataLen];
+            assembly{
+                pubKey := calldataLocation.offset
+            }
+            i += dataLen; // advance index
+
+            // parse length of authenticatorData
+            dataLen = 32;
+            paramLen = abi.decode(userOp.signature[i:i+dataLen], (uint256));
+            i += dataLen; // advance index
+            // assign authenticatorData to sig splice
+            dataLen = paramLen;//((paramLen >> 5) + 1) << 5; // (round up to next slot)
+
+            authenticatorData = userOp.signature[i:i+dataLen];
+            i += ((dataLen >> 5) + 1) << 5; // advance index (round up to next slot)
+
+            // parse length of clientData
+            dataLen = 32;
+            paramLen = abi.decode(userOp.signature[i:i+dataLen], (uint256));
+            i += dataLen; // advance index
+            // assign clientData to sig splice
+            dataLen = paramLen;// ((paramLen >> 5) + 1) << 5; // (round up to next slot)
+            clientData = userOp.signature[i:i+dataLen];
+            i += ((dataLen >> 5) + 1) << 5; // advance index (round up to next slot)
         }
+
+        bool verified = FCL_WebAuthn.checkSignature(
+            authenticatorData,
+            s.authenticatorDataFlagMask,
+            clientData,
+            userOpHash,
+            s.clientChallengeDataOffset,
+            signature,
+            pubKey
+        );
+        if (!verified) return SIG_VALIDATION_FAILED;
+        return 0;
     }
 
     /**

diff --git a/account-integrations/safe/src/lib/FCL_Webauthn.sol b/account-integrations/safe/src/lib/FCL_Webauthn.sol
@@ -76,13 +76,13 @@ library FCL_WebAuthn {
 
     /** @notice Modified from original Fresh Crypto Lib code to use memory instead of calldata */
     function checkSignature(
-        bytes memory authenticatorData,
+        bytes calldata authenticatorData,
         bytes1 authenticatorDataFlagMask,
-        bytes memory clientData,
+        bytes calldata clientData,
         bytes32 clientChallenge,
         uint256 clientChallengeDataOffset,
-        uint256[2] memory rs,
-        uint256[2] memory Q
+        uint256[2] calldata rs,
+        uint256[2] calldata Q
     ) internal returns (bool) {
         // Let the caller check if User Presence (0x01) or User Verification (0x04) are set
 

diff --git a/account-integrations/safe/test/forge/utils/TestHelper.sol b/account-integrations/safe/test/forge/utils/TestHelper.sol
@@ -118,5 +118,11 @@ abstract contract TestHelper is Test {
             signature,
             publicKey
         );
+        // console2.logString("authenticatorData");
+        // console2.logBytes(authenticatorData);
+        // console2.logString("flagMask");
+        // console2.logBytes1(authenticatorDataFlagMask);
+        // console2.logString("userOp");
+        // console2.logBytes(userOpSignature);
     }
 }
diff --git a/account-integrations/safe/test/hardhat/integration/SafeWebAuthnPlugin.test.ts b/account-integrations/safe/test/hardhat/integration/SafeWebAuthnPlugin.test.ts
@@ -75,7 +75,7 @@ describe("SafeWebAuthnPlugin", () => {
     const clientData =
       "0x7b2274797065223a22776562617574686e2e676574222c226368616c6c656e6765223a22efbfbd22efbfbd5f21efbfbd1b113e63efbfbdefbfbd6defbfbd4fefbfbdefbfbd11efbfbd11efbfbd40efbfbdefbfbdefbfbd64efbfbdefbfbd3cefbfbd58222c226f726967696e223a2268747470733a2f2f646576656c6f706d656e742e666f72756d64616f732e636f6d227d";
     const clientChallengeDataOffset = 36;
-    const signature = [
+    const signature: [BigNumberish, BigNumberish] = [
       BigInt(
         "36788204816852931931532076736929768488646494203674172515272861180041446565109"
       ),