From 0f8319dceb2d21a9d1ec74f78203b033f25c0969 Mon Sep 17 00:00:00 2001
From: Tim Burke <tim.burke@gmail.com>
Date: Fri, 22 Jan 2016 13:31:34 -0800
Subject: [PATCH] Use calendar.timegm not time.mktime

time.mktime produces a POSIX timestamp that takes into account the local
timezone, but we're parsing a Last-Modified header with a known (GMT)
timezone. As a result, if one proxy-server is configured with a timezone
other than GMT/UTC, we may have previous versions in the wrong order.

Change-Id: I320e2368b243f4245725e73bfabc7ad19bc5bacb
---
 swift/common/middleware/versioned_writes.py   |  7 +++--
 .../middleware/test_versioned_writes.py       | 29 +++++++++++++++++--
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/swift/common/middleware/versioned_writes.py b/swift/common/middleware/versioned_writes.py
index cc5830fdb3..94542043f2 100644
--- a/swift/common/middleware/versioned_writes.py
+++ b/swift/common/middleware/versioned_writes.py
@@ -115,6 +115,7 @@ Disable versioning from a container (x is any value except empty)::
 -H "X-Remove-Versions-Location: x" http://<storage_url>/container
 """
 
+import calendar
 import json
 import six
 from six.moves.urllib.parse import quote, unquote
@@ -209,9 +210,9 @@ class VersionedWritesContext(WSGIContext):
             lprefix = prefix_len + object_name + '/'
             ts_source = hresp.environ.get('swift_x_timestamp')
             if ts_source is None:
-                ts_source = time.mktime(time.strptime(
-                                        hresp.headers['last-modified'],
-                                        '%a, %d %b %Y %H:%M:%S GMT'))
+                ts_source = calendar.timegm(time.strptime(
+                                            hresp.headers['last-modified'],
+                                            '%a, %d %b %Y %H:%M:%S GMT'))
             new_ts = Timestamp(ts_source).internal
             vers_obj_name = lprefix + new_ts
             copy_headers = {
diff --git a/test/unit/common/middleware/test_versioned_writes.py b/test/unit/common/middleware/test_versioned_writes.py
index 87f2c525d4..64a31a6705 100644
--- a/test/unit/common/middleware/test_versioned_writes.py
+++ b/test/unit/common/middleware/test_versioned_writes.py
@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import functools
+import os
+import time
 import unittest
 from swift.common import swob
 from swift.common.middleware import versioned_writes
@@ -31,6 +34,26 @@ class FakeCache(object):
         return self.val
 
 
+def local_tz(func):
+    '''
+    Decorator to change the timezone when running a test.
+
+    This uses the Eastern Time Zone definition from the time module's docs.
+    Note that the timezone affects things like time.time() and time.mktime().
+    '''
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        tz = os.environ.get('TZ', '')
+        try:
+            os.environ['TZ'] = 'EST+05EDT,M4.1.0,M10.5.0'
+            time.tzset()
+            return func(*args, **kwargs)
+        finally:
+            os.environ['TZ'] = tz
+            time.tzset()
+    return wrapper
+
+
 class VersionedWritesTestCase(unittest.TestCase):
     def setUp(self):
         self.app = FakeSwift()
@@ -327,12 +350,13 @@ class VersionedWritesTestCase(unittest.TestCase):
         self.assertEqual(len(self.authorized), 1)
         self.assertRequestEqual(req, self.authorized[0])
 
+    @local_tz
     def test_new_version_sysmeta_precedence(self):
         self.app.register(
             'PUT', '/v1/a/c/o', swob.HTTPOk, {}, 'passed')
         self.app.register(
             'HEAD', '/v1/a/c/o', swob.HTTPOk,
-            {'last-modified': 'Wed, 19 Nov 2014 18:19:02 GMT'}, 'passed')
+            {'last-modified': 'Thu, 1 Jan 1970 00:00:00 GMT'}, 'passed')
         self.app.register(
             'COPY', '/v1/a/c/o', swob.HTTPCreated, {}, None)
 
@@ -354,7 +378,8 @@ class VersionedWritesTestCase(unittest.TestCase):
         method, path, req_headers = calls[1]
         self.assertEqual('COPY', method)
         self.assertEqual('/v1/a/c/o', path)
-        self.assertTrue(req_headers['Destination'].startswith('ver_cont/'))
+        self.assertEqual('ver_cont/001o/0000000000.00000',
+                         req_headers['Destination'])
 
     def test_copy_first_version(self):
         self.app.register(