Move auth_str_equal() to a new authutils module.

This patch moves auth_str_utils() to a new module, authutils, for
helper functions related to authentication.

Change-Id: I83f174486269701deed3500f890832a71ff3e315

2 files changed, 44 insertions, 24 deletions

diff --git a/openstack/common/authutils.py b/openstack/common/authutils.py
new file mode 100644
index 0000000..f0e2c80
--- /dev/null
+++ b/openstack/common/authutils.py
@@ -0,0 +1,44 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""
+Authentication related utilities and helper functions.
+"""
+
+
+def auth_str_equal(provided, known):
+    """Constant-time string comparison.
+
+    :params provided: the first string
+    :params known: the second string
+
+    :return: True if the strings are equal.
+
+    This function takes two strings and compares them.  It is intended to be
+    used when doing a comparison for authentication purposes to help guard
+    against timing attacks.  When using the function for this purpose, always
+    provide the user-provided password as the first argument.  The time this
+    function will take is always a factor of the length of this string.
+    """
+    result = 0
+    p_len = len(provided)
+    k_len = len(known)
+    for i in xrange(p_len):
+        a = ord(provided[i]) if i < p_len else 0
+        b = ord(known[i]) if i < k_len else 0
+        result |= a ^ b
+    return (p_len == k_len) & (result == 0)
diff --git a/openstack/common/utils.py b/openstack/common/utils.py
index d3d01fa..f9dfe73 100644
--- a/openstack/common/utils.py
+++ b/openstack/common/utils.py
@@ -158,27 +158,3 @@ def import_object(import_str):
         return sys.modules[import_str]
     except ImportError:
         return import_class(import_str)
-
-
-def auth_str_equal(provided, known):
-    """Constant-time string comparison.
-
-    :params provided: the first string
-    :params known: the second string
-
-    :return: True if the strings are equal.
-
-    This function takes two strings and compares them.  It is intended to be
-    used when doing a comparison for authentication purposes to help guard
-    against timing attacks.  When using the function for this purpose, always
-    provide the user-provided password as the first argument.  The time this
-    function will take is always a factor of the length of this string.
-    """
-    result = 0
-    p_len = len(provided)
-    k_len = len(known)
-    for i in xrange(p_len):
-        a = ord(provided[i]) if i < p_len else 0
-        b = ord(known[i]) if i < k_len else 0
-        result |= a ^ b
-    return (p_len == k_len) & (result == 0)