From 8468152b83e4decb3a0db664e34204bc386f8b84 Mon Sep 17 00:00:00 2001 From: =?utf-8?q?Jakub=20Ku=C5=BAma?= Date: Fri, 11 Sep 2009 09:13:14 +0200 Subject: [PATCH] ruby 1.9 friendly secure_compare --- .../lib/active_support/message_verifier.rb | 15 ++++++--------- 1 files changed, 6 insertions(+), 9 deletions(-) diff --git a/activesupport/lib/active_support/message_verifier.rb b/activesupport/lib/active_support/message_verifier.rb index 8d14423..5596784 100644 --- a/activesupport/lib/active_support/message_verifier.rb +++ b/activesupport/lib/active_support/message_verifier.rb @@ -38,24 +38,21 @@ module ActiveSupport end private - if "foo".respond_to?(:force_encoding) + if "foo".respond_to?(:bytesize) # constant-time comparison algorithm to prevent timing attacks + # > 1.8.6 friendly version def secure_compare(a, b) - a = a.force_encoding(Encoding::BINARY) - b = b.force_encoding(Encoding::BINARY) - - if a.length == b.length + if a.bytesize == b.bytesize result = 0 - for i in 0..(a.length - 1) - result |= a[i].ord ^ b[i].ord - end + j = b.each_byte + a.each_byte { |i| result |= i ^ j.next } result == 0 else false end end else - # For 1.8 + # For <= 1.8.6 def secure_compare(a, b) if a.length == b.length result = 0 -- 1.6.0.4