From d53bb61d4762bf276d2fae68b18cd20efbe2a498 Mon Sep 17 00:00:00 2001
From: Shane <jonas.shane@gmail.com>
Date: Wed, 12 May 2021 15:12:46 -0700
Subject: [PATCH] return early from metaRPCHandler if stream has ended (#11065)

* return early from metaRPCHandler if stream has ended

* add write after end guard to handleUpdate
---
 app/scripts/lib/createMetaRPCHandler.js      |  6 ++++
 app/scripts/lib/createMetaRPCHandler.test.js | 36 ++++++++++++++++++++
 app/scripts/metamask-controller.js           |  3 ++
 3 files changed, 45 insertions(+)

diff --git a/app/scripts/lib/createMetaRPCHandler.js b/app/scripts/lib/createMetaRPCHandler.js
index 24ac0ff6a..9b25c6ce7 100644
--- a/app/scripts/lib/createMetaRPCHandler.js
+++ b/app/scripts/lib/createMetaRPCHandler.js
@@ -2,6 +2,9 @@ import { ethErrors, serializeError } from 'eth-rpc-errors';
 
 const createMetaRPCHandler = (api, outStream) => {
   return (data) => {
+    if (outStream._writableState.ended) {
+      return;
+    }
     if (!api[data.method]) {
       outStream.write({
         jsonrpc: '2.0',
@@ -13,6 +16,9 @@ const createMetaRPCHandler = (api, outStream) => {
       return;
     }
     api[data.method](...data.params, (err, result) => {
+      if (outStream._writableState.ended) {
+        return;
+      }
       if (err) {
         outStream.write({
           jsonrpc: '2.0',
diff --git a/app/scripts/lib/createMetaRPCHandler.test.js b/app/scripts/lib/createMetaRPCHandler.test.js
index e37985105..c3f644ec8 100644
--- a/app/scripts/lib/createMetaRPCHandler.test.js
+++ b/app/scripts/lib/createMetaRPCHandler.test.js
@@ -58,4 +58,40 @@ describe('createMetaRPCHandler', function () {
       done();
     });
   });
+  it('can not throw an error for writing an error after end', function (done) {
+    const api = {
+      foo: (param1, cb) => {
+        assert.strictEqual(param1, 'bar');
+        cb(new Error('foo-error'));
+      },
+    };
+    const streamTest = createThoughStream();
+    const handler = createMetaRPCHandler(api, streamTest);
+    streamTest.end();
+    handler({
+      id: 1,
+      method: 'foo',
+      params: ['bar'],
+    });
+    done();
+  });
+  it('can not throw an error for write after end', function (done) {
+    const api = {
+      foo: (param1, cb) => {
+        assert.strictEqual(param1, 'bar');
+        cb(undefined, {
+          foo: 'bar',
+        });
+      },
+    };
+    const streamTest = createThoughStream();
+    const handler = createMetaRPCHandler(api, streamTest);
+    streamTest.end();
+    handler({
+      id: 1,
+      method: 'foo',
+      params: ['bar'],
+    });
+    done();
+  });
 });
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 2ae3c6ef1..00b3115c8 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -2024,6 +2024,9 @@ export default class MetamaskController extends EventEmitter {
     // set up postStream transport
     outStream.on('data', createMetaRPCHandler(api, outStream));
     const handleUpdate = (update) => {
+      if (outStream._writableState.ended) {
+        return;
+      }
       // send notification to client-side
       outStream.write({
         jsonrpc: '2.0',