Feature/lit 3379 investigate bls signed session bug

packages/lit-node-client-nodejs/src/lib/helpers/validate-bls-session-sig.ts

@@ -0,0 +1,40 @@
+import { AuthSig } from '@lit-protocol/types';
+import { uint8arrayToString } from '@lit-protocol/uint8arrays';
+import { ethers } from 'ethers';
+
+const LIT_SESSION_SIGNED_MESSAGE_PREFIX = 'lit_session:';
+
+/**
+ * Verifies a BLS session signature.
+ *
+ * @param {Function} verifier - A wasm function that takes a public key, message, and signature to verify. NOTE: `public_key` is snake cased because it's a wasm parameter
+ * @param {string} networkPubKey - The public key of the network.
+ * @param {AuthSig} authSig
+ * @typedef {Object} AuthSig
+ * @property {string} sig - The signature in string format.
+ * @property {string} signedMessage - The message that was signed.
+ */
+export const blsSessionSigVerify = (
+  // TODO: refactor type with merger of PR 'https://github.com/LIT-Protocol/js-sdk/pull/503`
+  verifier: (public_key: any, message: any, signature: any) => void,
+  networkPubKey: string,
+  authSig: AuthSig
+): void => {
+  let sigJson = JSON.parse(authSig.sig);
+  // we do not nessesarly need to use ethers here but was a quick way
+  // to get verification working.
+  const eip191Hash = ethers.utils.hashMessage(authSig.signedMessage);
+  const prefixedStr =
+    LIT_SESSION_SIGNED_MESSAGE_PREFIX + eip191Hash.replace('0x', '');
+  const prefixedEncoded = ethers.utils.toUtf8Bytes(prefixedStr);
+  const shaHashed = ethers.utils.base64.encode(
+    ethers.utils.sha256(prefixedEncoded)
+  );
+  const signatureBytes = Buffer.from(sigJson.ProofOfPossession, `hex`);
+
+  verifier(
+    networkPubKey,
+    shaHashed,
+    uint8arrayToString(signatureBytes, `base64`)
+  );
+};

packages/lit-node-client-nodejs/src/lib/helpers/validate-bls-session-sigs.spec.ts

@@ -0,0 +1,41 @@
+import { blsSessionSigVerify } from './validate-bls-session-sig';
+
+describe('BlsSessionSigVerify', () => {
+  const authSig = {
+    sig: '{"ProofOfPossession":"ae925162cecb2f572fa76b93372dbbaee0133e89987c33d3210e0d62ca2dd5bf080dbdabb0155e61e770be1a2a629861073acc58fbc16cb6b700088d2aff114c42337c6123c8d15eeee63b522ea7d9c8f44390d3cb7b26e8d4935a283fe72a5d"}',
+    algo: 'LIT_BLS',
+    derivedVia: 'lit.bls',
+    signedMessage:
+      'litprotocol.com wants you to sign in with your Ethereum account:\n' +
+      '0xf087a967D9eA9445D9182692C2944DcC0Af57341\n' +
+      '\n' +
+      "Lit Protocol PKP session signature I further authorize the stated URI to perform the following actions on my behalf: I further authorize the stated URI to perform the following actions on my behalf: (1) 'Threshold': 'Execution' for 'lit-litaction://*'. (2) 'Threshold': 'Signing' for 'lit-pkp://*'. I further authorize the stated URI to perform the following actions on my behalf: (1) 'Threshold': 'Execution' for 'lit-litaction://*'. (2) 'Threshold': 'Signing' for 'lit-pkp://*'. (3) 'Auth': 'Auth' for 'lit-resolvedauthcontext://*'.\n" +
+      '\n' +
+      'URI: lit:session:efebafcc9063827a49dffdb11c36b2d64a33330631ac7f5825e2960946bcc8ff\n' +
+      'Version: 1\n' +
+      'Chain ID: 1\n' +
+      'Nonce: 0x1f623ab8dfe6bbd3b3dc22c7a041deb697c14817bce471b1bd1d86a25d5a319c\n' +
+      'Issued At: 2024-06-11T15:55:23Z\n' +
+      'Expiration Time: 2024-06-12T15:55:47.655Z\n' +
+      'Resources:\n' +
+      '- urn:recap: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',
+    address: '0xf087a967D9eA9445D9182692C2944DcC0Af57341',
+  };
+
+  let networkPubKey =
+    'a43499a4b786da2dd28af9f209eb152ff6f646b34b68a02954967271e17fb4c511fd67b81e067f690c6f38acab70585d';
+
+  it(`should verify valid bls signatrue`, () => {
+    expect(
+      blsSessionSigVerify(
+        (public_key: any, message: any, signature: any) => {
+          expect(typeof public_key).toBe('string');
+          expect(typeof message).toBe('string');
+          expect(typeof signature).toBe('string');
+        },
+        networkPubKey,
+        authSig
+      )
+    ).toBeUndefined();
+  });
+});

packages/lit-node-client-nodejs/src/lib/lit-node-client-nodejs.ts

@@ -126,6 +126,7 @@ import { normalizeArray } from './helpers/normalize-array';
 import { parsePkpSignResponse } from './helpers/parse-pkp-sign-response';
 import { getBlsSignatures } from './helpers/get-bls-signatures';
 import { processLitActionResponseStrategy } from './helpers/process-lit-action-response-strategy';
+import { blsSessionSigVerify } from './helpers/validate-bls-session-sig';
 
 export class LitNodeClientNodeJs
   extends LitCore
@@ -512,17 +513,38 @@ export class LitNodeClientNodeJs
     resourceAbilityRequests: LitResourceAbilityRequest[];
   }): Promise<boolean> => {
     const authSigSiweMessage = new SiweMessage(authSig.signedMessage);
-
-    try {
-      await authSigSiweMessage.validate(authSig.sig);
-    } catch (e) {
-      console.debug('Need retry because verify failed', e);
-      return true;
+    // We will either have `ed25519` or `LIT_BLS` as we have deviated from the specification of SIWE and use BLS signatures in some cases
+    // Here we need to check the `algo` of the SIWE to confirm we can validate the signature as if we attempt to validate the BLS signature here
+    // it will fail. If the  algo is not defined we can assume that it was an EOA wallet signing the message so we can use SIWE.
+    if (authSig.algo === `ed25519` || authSig.algo === undefined) {
+      try {
+        await authSigSiweMessage.validate(authSig.sig);
+      } catch (e) {
+        log(`Error while verifying ECDSA signature: `, e);
+        return true;
+      }
+    } else if (authSig.algo === `LIT_BLS`) {
+      try {
+        blsSessionSigVerify(
+          blsSdk.verify_signature,
+          this.networkPubKey!,
+          authSig
+        );
+      } catch (e) {
+        log(`Error while verifying bls signature: `, e);
+        return true;
+      }
+    } else {
+      throwError({
+        message: `Unsupported signature algo for session signature. Expected ed25519 or LIT_BLS recieved ${authSig.algo}`,
+        errorKind: LIT_ERROR.SIGNATURE_VALIDATION_ERROR.kind,
+        errorCode: LIT_ERROR.SIGNATURE_VALIDATION_ERROR.code,
+      });
     }
 
     // make sure the sig is for the correct session key
     if (authSigSiweMessage.uri !== sessionKeyUri) {
-      console.debug('Need retry because uri does not match');
+      log('Need retry because uri does not match');
       return true;
     }
 
@@ -531,7 +553,7 @@ export class LitNodeClientNodeJs
       !authSigSiweMessage.resources ||
       authSigSiweMessage.resources.length === 0
     ) {
-      console.debug('Need retry because empty resources');
+      log('Need retry because empty resources');
       return true;
     }
 
@@ -550,7 +572,7 @@ export class LitNodeClientNodeJs
           resourceAbilityRequest.ability
         )
       ) {
-        console.debug('Need retry because capabilities do not match', {
+        log('Need retry because capabilities do not match', {
           authSigSessionCapabilityObject,
           resourceAbilityRequest,
         });
@@ -1881,6 +1903,7 @@ export class LitNodeClientNodeJs
 
     log(`[signSessionKey] signatureShares:`, signatureShares);
 
+    // TODO: refactor type with merger of PR 'https://github.com/LIT-Protocol/js-sdk/pull/503`
     const blsCombinedSignature = blsSdk.combine_signature_shares(
       signatureShares.map((s) => JSON.stringify(s))
     );