From f97a7adae5b2340c830878d0947829d7be2e09ef Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Wed, 9 May 2012 10:42:59 +0200
Subject: [PATCH] Allow clock skews in certificate verification
Currently we allow for up to NODE_MAX_CLOCK_SKEW time difference
between nodes in some operations, but not everywhere: SSL certificate
verification (import/export, both intra and inter-cluster) has a zero
limit (downwards), and a week upwards. This can cause even
intra-cluster backup problems, if the source node has a time even two
seconds in the future.
To fix this, when we verify certificates compare with a time offset
with the max skew, which fixes the lower bound and reduces the upper
bound by an insignificant amount (0.04%).
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
lib/utils/x509.py | 6 +++--
test/ganeti.utils.x509_unittest.py | 39 +++++++++++++++++++++++++++++-
2 files changed, 42 insertions(+), 3 deletions(-)
diff --git a/lib/utils/x509.py b/lib/utils/x509.py
index b0d9f904c..0a91f41fa 100644
--- a/lib/utils/x509.py
+++ b/lib/utils/x509.py
@@ -1,7 +1,7 @@
#
#
-# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
+# Copyright (C) 2006, 2007, 2010, 2011, 2012 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@@ -180,8 +180,10 @@ def VerifyX509Certificate(cert, warn_days, error_days):
# Depending on the pyOpenSSL version, this can just return (None, None)
(not_before, not_after) = GetX509CertValidity(cert)
+ now = time.time() + constants.NODE_MAX_CLOCK_SKEW
+
return _VerifyCertificateInner(cert.has_expired(), not_before, not_after,
- time.time(), warn_days, error_days)
+ now, warn_days, error_days)
def SignX509Certificate(cert, key, salt):
diff --git a/test/ganeti.utils.x509_unittest.py b/test/ganeti.utils.x509_unittest.py
index 2249e896c..40425d214 100755
--- a/test/ganeti.utils.x509_unittest.py
+++ b/test/ganeti.utils.x509_unittest.py
@@ -1,7 +1,7 @@
#!/usr/bin/python
#
-# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
+# Copyright (C) 2006, 2007, 2010, 2011, 2012 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@@ -164,6 +164,43 @@ class TestCertVerification(testutils.GanetiTestCase):
# Not checking return value as this certificate is expired
utils.VerifyX509Certificate(cert, 30, 7)
+ @staticmethod
+ def _GenCert(key, before, validity):
+ # Urgh... mostly copied from x509.py :(
+
+ # Create self-signed certificate
+ cert = OpenSSL.crypto.X509()
+ cert.set_serial_number(1)
+ if before != 0:
+ cert.gmtime_adj_notBefore(int(before))
+ cert.gmtime_adj_notAfter(validity)
+ cert.set_issuer(cert.get_subject())
+ cert.set_pubkey(key)
+ cert.sign(key, constants.X509_CERT_SIGN_DIGEST)
+ return cert
+
+ def testClockSkew(self):
+ SKEW = constants.NODE_MAX_CLOCK_SKEW
+ # Create private and public key
+ key = OpenSSL.crypto.PKey()
+ key.generate_key(OpenSSL.crypto.TYPE_RSA, constants.RSA_KEY_BITS)
+
+ validity = 7 * 86400
+ # skew small enough, accepting cert; note that this is a timed
+ # test, and could fail if the machine is so loaded that the next
+ # few lines take more than NODE_MAX_CLOCK_SKEW / 2
+ for before in [-1, 0, SKEW / 4, SKEW / 2]:
+ cert = self._GenCert(key, before, validity)
+ result = utils.VerifyX509Certificate(cert, 1, 2)
+ self.assertEqual(result, (None, None))
+
+ # skew too great, not accepting certs
+ for before in [SKEW + 1, SKEW * 2, SKEW * 10]:
+ cert = self._GenCert(key, before, validity)
+ (status, msg) = utils.VerifyX509Certificate(cert, 1, 2)
+ self.assertEqual(status, utils.CERT_WARNING)
+ self.assertTrue(msg.startswith("Certificate not yet valid"))
+
class TestVerifyCertificateInner(unittest.TestCase):
def test(self):
--
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