From c0eed792a22865b280f99cbb79076fa7ad19fcbb Mon Sep 17 00:00:00 2001

From: Samuel Merritt <[email protected]>

Date: Thu, 16 Jan 2014 12:45:52 +0000

Subject: Use constant time comparison in tempURL

Use constant time comparison when evaluating tempURL to avoid timing

attacks (CVE-2014-0006). This is the grizzly backport of the master

patch.

Fixes bug 1265665

Change-Id: I11e4ad83cc4077e52adf54a0bd0f9749294b2a48

---

diff --git a/swift/common/middleware/tempurl.py b/swift/common/middleware/tempurl.py

index 5a05de7..8a2517e 100644

--- a/swift/common/middleware/tempurl.py

+++ b/swift/common/middleware/tempurl.py

@@ -98,6 +98,7 @@ from urlparse import parse_qs

 from swift.common.wsgi import make_pre_authed_env

 from swift.common.http import HTTP_UNAUTHORIZED

+from swift.common.utils import streq_const_time

 #: Default headers to remove from incoming requests. Simply a whitespace

@@ -248,14 +249,14 @@ class TempURL(object):

         if env['REQUEST_METHOD'] == 'HEAD':

             hmac_val = self._get_hmac(env, temp_url_expires, key,

                                       request_method='GET')

-            if temp_url_sig != hmac_val:

+            if not streq_const_time(temp_url_sig, hmac_val):

                 hmac_val = self._get_hmac(env, temp_url_expires, key,

                                           request_method='PUT')

-                if temp_url_sig != hmac_val:

+                if not streq_const_time(temp_url_sig, hmac_val):

                     return self._invalid(env, start_response)

         else:

             hmac_val = self._get_hmac(env, temp_url_expires, key)

-            if temp_url_sig != hmac_val:

+            if not streq_const_time(temp_url_sig, hmac_val):

                 return self._invalid(env, start_response)

         self._clean_incoming_headers(env)

         env['swift.authorize'] = lambda req: None