From 25307d58d340260679a1940ead3c585964afeb8b Mon Sep 17 00:00:00 2001
From: Kyle Peacock <kylpeacock@gmail.com>
Date: Wed, 7 Sep 2022 11:31:55 -0700
Subject: [PATCH] feat: support for bls verification polyfill (#626)

* feat: support for polyfill of blsVerify
---
 docs/generated/changelog.html              |  4 ++++
 e2e/node/basic/canisterStatus.test.ts      |  3 +++
 packages/agent/src/actor.ts                | 17 ++++++++++++++---
 packages/agent/src/canisterStatus/index.ts |  2 ++
 packages/agent/src/certificate.ts          | 22 +++++++++++++++++++---
 packages/agent/src/polling/index.ts        |  4 +++-
 6 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/docs/generated/changelog.html b/docs/generated/changelog.html
index e7b6bd536..cd367daa8 100644
--- a/docs/generated/changelog.html
+++ b/docs/generated/changelog.html
@@ -10,6 +10,10 @@
     <h1>Agent-JS Changelog</h1>
 
     <section>
+      <h2>Version 0.13.3</h2>
+      <ul>
+        <li>adds ability to polyfill bls verification in Certificate</li>
+      </ul>
       <h2>Version 0.13.2</h2>
       <ul>
         <li>auth-client avoids localstorage global and can be used in a web worker or nodejs</li>
diff --git a/e2e/node/basic/canisterStatus.test.ts b/e2e/node/basic/canisterStatus.test.ts
index 5b7e31cf9..dff687889 100644
--- a/e2e/node/basic/canisterStatus.test.ts
+++ b/e2e/node/basic/canisterStatus.test.ts
@@ -3,6 +3,9 @@ import { Principal } from '@dfinity/principal';
 import counter from '../canisters/counter';
 
 jest.setTimeout(30_000);
+afterEach(async () => {
+  await Promise.resolve();
+});
 describe.only('canister status', () => {
   it('should fetch successfully', async () => {
     const counterObj = await (await counter)();
diff --git a/packages/agent/src/actor.ts b/packages/agent/src/actor.ts
index 270455679..5e6dfc5ec 100644
--- a/packages/agent/src/actor.ts
+++ b/packages/agent/src/actor.ts
@@ -14,6 +14,7 @@ import { pollForResponse, PollStrategyFactory, strategy } from './polling';
 import { Principal } from '@dfinity/principal';
 import { RequestId } from './request_id';
 import { toHex } from './utils/buffer';
+import { CreateCertificateOptions } from './certificate';
 
 export class ActorCallError extends AgentError {
   constructor(
@@ -115,6 +116,11 @@ export interface ActorConfig extends CallConfig {
     args: unknown[],
     callConfig: CallConfig,
   ): Partial<CallConfig> | void;
+
+  /**
+   * Polyfill for BLS Certificate verification in case wasm is not supported
+   */
+  blsVerify?: CreateCertificateOptions['blsVerify'];
 }
 
 // TODO: move this to proper typing when Candid support TypeScript.
@@ -254,7 +260,7 @@ export class Actor {
         });
 
         for (const [methodName, func] of service._fields) {
-          this[methodName] = _createActorMethod(this, methodName, func);
+          this[methodName] = _createActorMethod(this, methodName, func, config.blsVerify);
         }
       }
     }
@@ -299,7 +305,12 @@ const DEFAULT_ACTOR_CONFIG = {
 
 export type ActorConstructor = new (config: ActorConfig) => ActorSubclass;
 
-function _createActorMethod(actor: Actor, methodName: string, func: IDL.FuncClass): ActorMethod {
+function _createActorMethod(
+  actor: Actor,
+  methodName: string,
+  func: IDL.FuncClass,
+  blsVerify?: CreateCertificateOptions['blsVerify'],
+): ActorMethod {
   let caller: (options: CallConfig, ...args: unknown[]) => Promise<unknown>;
   if (func.annotations.includes('query')) {
     caller = async (options, ...args) => {
@@ -357,7 +368,7 @@ function _createActorMethod(actor: Actor, methodName: string, func: IDL.FuncClas
       }
 
       const pollStrategy = pollingStrategyFactory();
-      const responseBytes = await pollForResponse(agent, ecid, requestId, pollStrategy);
+      const responseBytes = await pollForResponse(agent, ecid, requestId, pollStrategy, blsVerify);
 
       if (responseBytes !== undefined) {
         return decodeReturnValue(func.retTypes, responseBytes);
diff --git a/packages/agent/src/canisterStatus/index.ts b/packages/agent/src/canisterStatus/index.ts
index d4c151cce..3c31ae80b 100644
--- a/packages/agent/src/canisterStatus/index.ts
+++ b/packages/agent/src/canisterStatus/index.ts
@@ -4,6 +4,7 @@ import { lebDecode, PipeArrayBuffer } from '@dfinity/candid';
 import { Principal } from '@dfinity/principal';
 import { AgentError } from '../errors';
 import { HttpAgent, Cbor, Certificate, toHex } from '..';
+import type { CreateCertificateOptions } from '..';
 
 /**
  * Types of an entry on the canisterStatus map.
@@ -50,6 +51,7 @@ export type CanisterStatusOptions = {
   canisterId: Principal;
   agent: HttpAgent;
   paths?: Path[] | Set<Path>;
+  blsVerify?: CreateCertificateOptions['blsVerify'];
 };
 
 /**
diff --git a/packages/agent/src/certificate.ts b/packages/agent/src/certificate.ts
index a92824cd1..16262e37e 100644
--- a/packages/agent/src/certificate.ts
+++ b/packages/agent/src/certificate.ts
@@ -1,9 +1,9 @@
 import * as cbor from './cbor';
 import { AgentError } from './errors';
 import { hash } from './request_id';
-import { blsVerify } from './utils/bls';
 import { concat, fromHex, toHex } from './utils/buffer';
 import { Principal } from '@dfinity/principal';
+import * as bls from './utils/bls';
 
 /**
  * A certificate may fail verification with respect to the provided public key
@@ -98,6 +98,8 @@ function isBufferEqual(a: ArrayBuffer, b: ArrayBuffer): boolean {
   return true;
 }
 
+type VerifyFunc = (pk: Uint8Array, sig: Uint8Array, msg: Uint8Array) => Promise<boolean>;
+
 export interface CreateCertificateOptions {
   /**
    * The bytes encoding the certificate to be verified
@@ -113,6 +115,10 @@ export interface CreateCertificateOptions {
    * the signing canister ID when verifying a certified variable.
    */
   canisterId: Principal;
+  /**
+   * BLS Verification strategy. Default strategy uses wasm for performance, but that may not be available in all contexts.
+   */
+  blsVerify?: VerifyFunc;
 }
 
 export class Certificate {
@@ -130,7 +136,16 @@ export class Certificate {
    * @throws {CertificateVerificationError}
    */
   public static async create(options: CreateCertificateOptions): Promise<Certificate> {
-    const cert = new Certificate(options.certificate, options.rootKey, options.canisterId);
+    let blsVerify = options.blsVerify;
+    if (!blsVerify) {
+      blsVerify = bls.blsVerify;
+    }
+    const cert = new Certificate(
+      options.certificate,
+      options.rootKey,
+      options.canisterId,
+      blsVerify,
+    );
     await cert.verify();
     return cert;
   }
@@ -139,6 +154,7 @@ export class Certificate {
     certificate: ArrayBuffer,
     private _rootKey: ArrayBuffer,
     private _canisterId: Principal,
+    private _blsVerify: VerifyFunc,
   ) {
     this.cert = cbor.decode(new Uint8Array(certificate));
   }
@@ -155,7 +171,7 @@ export class Certificate {
     const msg = concat(domain_sep('ic-state-root'), rootHash);
     let sigVer = false;
     try {
-      sigVer = await blsVerify(new Uint8Array(key), new Uint8Array(sig), new Uint8Array(msg));
+      sigVer = await this._blsVerify(new Uint8Array(key), new Uint8Array(sig), new Uint8Array(msg));
     } catch (err) {
       sigVer = false;
     }
diff --git a/packages/agent/src/polling/index.ts b/packages/agent/src/polling/index.ts
index 788550583..09c1e445d 100644
--- a/packages/agent/src/polling/index.ts
+++ b/packages/agent/src/polling/index.ts
@@ -1,6 +1,6 @@
 import { Principal } from '@dfinity/principal';
 import { Agent, RequestStatusResponseStatus } from '../agent';
-import { Certificate } from '../certificate';
+import { Certificate, CreateCertificateOptions } from '../certificate';
 import { RequestId } from '../request_id';
 import { toHex } from '../utils/buffer';
 
@@ -29,6 +29,7 @@ export async function pollForResponse(
   strategy: PollStrategy,
   // eslint-disable-next-line
   request?: any,
+  blsVerify?: CreateCertificateOptions['blsVerify'],
 ): Promise<ArrayBuffer> {
   const path = [new TextEncoder().encode('request_status'), requestId];
   const currentRequest = request ?? (await agent.createReadStateRequest?.({ paths: [path] }));
@@ -38,6 +39,7 @@ export async function pollForResponse(
     certificate: state.certificate,
     rootKey: agent.rootKey,
     canisterId: canisterId,
+    blsVerify,
   });
   const maybeBuf = cert.lookup([...path, new TextEncoder().encode('status')]);
   let status;