From 9a9a5b236545838436169fccc6ac7658e04eb7f6 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 26 Feb 2021 15:51:32 +0100
Subject: [PATCH] Replace the `compareByteArrays` functions, in
 `src/core/crypto.js`, with the `isArrayEqual` helper function

The `compareByteArrays` is first of all duplicated in multiple closures in the `src/core/crypto.js` file. Secondly, despite its name, it's also functionally equivalent to the now existing `isArrayEqual` helper function.

The `isArrayEqual` helper function is changed to use a standard `for`-loop, rather than `Array.prototype.every`, since that ought to be slightly more efficient given that we're now using it with (potentially) larger data.
---
 src/core/crypto.js | 33 +++++----------------------------
 src/shared/util.js |  9 ++++++---
 2 files changed, 11 insertions(+), 31 deletions(-)

diff --git a/src/core/crypto.js b/src/core/crypto.js
index 45d439a2e..dfd88f06c 100644
--- a/src/core/crypto.js
+++ b/src/core/crypto.js
@@ -17,6 +17,7 @@
 import {
   bytesToString,
   FormatError,
+  isArrayEqual,
   PasswordException,
   PasswordResponses,
   stringToBytes,
@@ -1262,18 +1263,6 @@ class AES256Cipher extends AESBaseCipher {
 }
 
 var PDF17 = (function PDF17Closure() {
-  function compareByteArrays(array1, array2) {
-    if (array1.length !== array2.length) {
-      return false;
-    }
-    for (var i = 0; i < array1.length; i++) {
-      if (array1[i] !== array2[i]) {
-        return false;
-      }
-    }
-    return true;
-  }
-
   // eslint-disable-next-line no-shadow
   function PDF17() {}
 
@@ -1289,7 +1278,7 @@ var PDF17 = (function PDF17Closure() {
       hashData.set(ownerValidationSalt, password.length);
       hashData.set(userBytes, password.length + ownerValidationSalt.length);
       var result = calculateSHA256(hashData, 0, hashData.length);
-      return compareByteArrays(result, ownerPassword);
+      return isArrayEqual(result, ownerPassword);
     },
     checkUserPassword: function PDF17_checkUserPassword(
       password,
@@ -1300,7 +1289,7 @@ var PDF17 = (function PDF17Closure() {
       hashData.set(password, 0);
       hashData.set(userValidationSalt, password.length);
       var result = calculateSHA256(hashData, 0, hashData.length);
-      return compareByteArrays(result, userPassword);
+      return isArrayEqual(result, userPassword);
     },
     getOwnerKey: function PDF17_getOwnerKey(
       password,
@@ -1385,18 +1374,6 @@ var PDF20 = (function PDF20Closure() {
   // eslint-disable-next-line no-shadow
   function PDF20() {}
 
-  function compareByteArrays(array1, array2) {
-    if (array1.length !== array2.length) {
-      return false;
-    }
-    for (var i = 0; i < array1.length; i++) {
-      if (array1[i] !== array2[i]) {
-        return false;
-      }
-    }
-    return true;
-  }
-
   PDF20.prototype = {
     hash: function PDF20_hash(password, concatBytes, userBytes) {
       return calculatePDF20Hash(password, concatBytes, userBytes);
@@ -1412,7 +1389,7 @@ var PDF20 = (function PDF20Closure() {
       hashData.set(ownerValidationSalt, password.length);
       hashData.set(userBytes, password.length + ownerValidationSalt.length);
       var result = calculatePDF20Hash(password, hashData, userBytes);
-      return compareByteArrays(result, ownerPassword);
+      return isArrayEqual(result, ownerPassword);
     },
     checkUserPassword: function PDF20_checkUserPassword(
       password,
@@ -1423,7 +1400,7 @@ var PDF20 = (function PDF20Closure() {
       hashData.set(password, 0);
       hashData.set(userValidationSalt, password.length);
       var result = calculatePDF20Hash(password, hashData, []);
-      return compareByteArrays(result, userPassword);
+      return isArrayEqual(result, userPassword);
     },
     getOwnerKey: function PDF20_getOwnerKey(
       password,
diff --git a/src/shared/util.js b/src/shared/util.js
index a5fbd5220..c175f0a2b 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -884,9 +884,12 @@ function isArrayEqual(arr1, arr2) {
   if (arr1.length !== arr2.length) {
     return false;
   }
-  return arr1.every(function (element, index) {
-    return element === arr2[index];
-  });
+  for (let i = 0, ii = arr1.length; i < ii; i++) {
+    if (arr1[i] !== arr2[i]) {
+      return false;
+    }
+  }
+  return true;
 }
 
 function getModificationDate(date = new Date()) {