From 2cfdaca3c1e2dd232d2c18bb4fd231f181aec7ad Mon Sep 17 00:00:00 2001
From: Scott Nonnenberg <scott@nonnenberg.com>
Date: Wed, 14 Feb 2018 12:15:26 -0800
Subject: [PATCH] Make our binary comparisons constant time (#2047)

---
 js/models/conversations.js  | 6 +++---
 js/signal_protocol_store.js | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/js/models/conversations.js b/js/models/conversations.js
index 04a256c63f98..45320b861338 100644
--- a/js/models/conversations.js
+++ b/js/models/conversations.js
@@ -32,13 +32,13 @@
         if (ab1.byteLength !== ab2.byteLength) {
             return false;
         }
-        var result = true;
+        var result = 0;
         var ta1 = new Uint8Array(ab1);
         var ta2 = new Uint8Array(ab2);
         for (var i = 0; i < ab1.byteLength; ++i) {
-            if (ta1[i] !== ta2[i]) { result = false; }
+            result = result | ta1[i] ^ ta2[i];
         }
-        return result;
+        return result === 0;
     }
 
   Whisper.Conversation = Backbone.Model.extend({
diff --git a/js/signal_protocol_store.js b/js/signal_protocol_store.js
index 245c7c5c0849..456fefa9b35d 100644
--- a/js/signal_protocol_store.js
+++ b/js/signal_protocol_store.js
@@ -78,13 +78,13 @@
         if (ab1.byteLength !== ab2.byteLength) {
             return false;
         }
-        var result = true;
+        var result = 0;
         var ta1 = new Uint8Array(ab1);
         var ta2 = new Uint8Array(ab2);
         for (var i = 0; i < ab1.byteLength; ++i) {
-            if (ta1[i] !== ta2[i]) { result = false; }
+            result = result | ta1[i] ^ ta2[i];
         }
-        return result;
+        return result === 0;
     }
 
     var Model = Backbone.Model.extend({ database: Whisper.Database });