From d13628f9c19856d0a3376ad4fbd269b51cb322a9 Mon Sep 17 00:00:00 2001
From: Akhil Marsonya <akhil.marsonya27@gmail.com>
Date: Fri, 16 Apr 2021 22:47:20 +0530
Subject: [PATCH] events: refactor to use primordials in lib/events

Replace code that's vulnerable to Prototype Pollution with Primordials.
---
 lib/events.js | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/lib/events.js b/lib/events.js
index 7d219606a28b1b..e35033d45eab21 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -22,10 +22,16 @@
 'use strict';
 
 const {
+  ArrayPrototypeIndexOf,
+  ArrayPrototypeJoin,
+  ArrayPrototypeShift,
   ArrayPrototypeSlice,
+  ArrayPrototypeSplice,
   Boolean,
   Error,
   ErrorCaptureStackTrace,
+  FunctionPrototypeBind,
+  FunctionPrototypeCall,
   MathMin,
   NumberIsNaN,
   ObjectCreate,
@@ -38,9 +44,10 @@ const {
   PromiseResolve,
   ReflectOwnKeys,
   String,
+  StringPrototypeSplit,
   Symbol,
   SymbolFor,
-  SymbolAsyncIterator
+  SymbolAsyncIterator,
 } = primordials;
 const kRejection = SymbolFor('nodejs.rejection');
 
@@ -270,7 +277,7 @@ EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
 function identicalSequenceRange(a, b) {
   for (let i = 0; i < a.length - 3; i++) {
     // Find the first entry of b that matches the current entry of a.
-    const pos = b.indexOf(a[i]);
+    const pos = ArrayPrototypeIndexOf(b, a[i]);
     if (pos !== -1) {
       const rest = b.length - pos;
       if (rest > 3) {
@@ -299,16 +306,18 @@ function enhanceStackTrace(err, own) {
   } catch {}
   const sep = `\nEmitted 'error' event${ctorInfo} at:\n`;
 
-  const errStack = err.stack.split('\n').slice(1);
-  const ownStack = own.stack.split('\n').slice(1);
+  const errStack = ArrayPrototypeSlice(
+    StringPrototypeSplit(err.stack, '\n'), 1);
+  const ownStack = ArrayPrototypeSlice(
+    StringPrototypeSplit(own.stack, '\n'), 1);
 
   const { 0: len, 1: off } = identicalSequenceRange(ownStack, errStack);
   if (len > 0) {
-    ownStack.splice(off + 1, len - 2,
-                    '    [... lines matching original stack trace ...]');
+    ArrayPrototypeSplice(ownStack, off + 1, len - 2,
+                         '    [... lines matching original stack trace ...]');
   }
 
-  return err.stack + sep + ownStack.join('\n');
+  return err.stack + sep + ArrayPrototypeJoin(ownStack, '\n');
 }
 
 EventEmitter.prototype.emit = function emit(type, ...args) {
@@ -332,7 +341,7 @@ EventEmitter.prototype.emit = function emit(type, ...args) {
         const capture = {};
         ErrorCaptureStackTrace(capture, EventEmitter.prototype.emit);
         ObjectDefineProperty(er, kEnhanceStackBeforeInspector, {
-          value: enhanceStackTrace.bind(this, er, capture),
+          value: FunctionPrototypeBind(enhanceStackTrace, this, er, capture),
           configurable: true
         });
       } catch {}
@@ -625,7 +634,7 @@ EventEmitter.listenerCount = function(emitter, type) {
   if (typeof emitter.listenerCount === 'function') {
     return emitter.listenerCount(type);
   }
-  return listenerCount.call(emitter, type);
+  return FunctionPrototypeCall(listenerCount, emitter, type);
 };
 
 EventEmitter.prototype.listenerCount = listenerCount;
@@ -863,7 +872,7 @@ function on(emitter, event, options) {
   }
 
   function eventHandler(...args) {
-    const promise = unconsumedPromises.shift();
+    const promise = ArrayPrototypeShift(unconsumedPromises);
     if (promise) {
       promise.resolve(createIterResult(args, false));
     } else {
@@ -874,7 +883,7 @@ function on(emitter, event, options) {
   function errorHandler(err) {
     finished = true;
 
-    const toError = unconsumedPromises.shift();
+    const toError = ArrayPrototypeShift(unconsumedPromises);
 
     if (toError) {
       toError.reject(err);