Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Christian Heimes 
On 2015-07-23 11:06, Alexander Bokovoy wrote:
 On Thu, 23 Jul 2015, Christian Heimes wrote:
 This patch removes the dependency on M2Crypto in favor for cryptography.
 Cryptography is more strict about the key size and doesn't support
 non-standard key sizes:

 from M2Crypto import RC4
 from ipaserver.dcerpc import arcfour_encrypt
 RC4.RC4(b'key').update(b'data')
 'o\r@\x8c'
 arcfour_encrypt(b'key', b'data')
 Traceback (most recent call last):
 ...
 ValueError: Invalid key size (24) for RC4.

 Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

 arcfour_encrypt(b'key12', b'data')
 '\xcd\xf80d'
 RC4.RC4(b'key12').update(b'data')
 '\xcd\xf80d'
 Note that we are using NTLMv2 or Kerberos user session keys which are
 128 bit long in this context.
 
 And please rework the spec file change as Honza noted.

Thanks for the feedback regarding the key size, 128bit works.

Is RC4 really the only supported algorithm for session keys? RC4 is
insecure, especially the first few bytes have a high bias. It may not be
much of an issue for short-lived session keys, though.

Christian



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Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Alexander Bokovoy 

On Thu, 23 Jul 2015, Christian Heimes wrote:

On 2015-07-23 11:06, Alexander Bokovoy wrote:

On Thu, 23 Jul 2015, Christian Heimes wrote:

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:


from M2Crypto import RC4
from ipaserver.dcerpc import arcfour_encrypt
RC4.RC4(b'key').update(b'data')

'o\r@\x8c'

arcfour_encrypt(b'key', b'data')

Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:


arcfour_encrypt(b'key12', b'data')

'\xcd\xf80d'

RC4.RC4(b'key12').update(b'data')

'\xcd\xf80d'

Note that we are using NTLMv2 or Kerberos user session keys which are
128 bit long in this context.

And please rework the spec file change as Honza noted.


Thanks for the feedback regarding the key size, 128bit works.

Is RC4 really the only supported algorithm for session keys? RC4 is
insecure, especially the first few bytes have a high bias. It may not be
much of an issue for short-lived session keys, though.

It is not a session key algorithm. It is an algorithm used to encrypt
trust authentication information when passing it over. We pass trust
authentication information in clear, then encrypt it with a session key
for the transfer and on the receiving side DC does unwrapping and uses
the clear-text version of the trust secret to derive all needed
cross-realm keys.

MS-LSAD puts it this way (5.1.1):
-
Implementations of this protocol protect the LSAPR_TRUSTED_DOMAIN_AUTH_BLOB
structure by encrypting the data referenced by that structure's AuthBlob
field.  The RC4 algorithm is used to encrypt the data on request (and
reply) and decrypt the data on receipt.  The key, required during
runtime by the RC4 algorithm, is the 16-byte key specified by the method
that uses this structure (for example, see section 3.1.4.7.10). The size
of data (the AuthSize field of LSAPR_TRUSTED_DOMAIN_AUTH_BLOB) must
remain unencrypted.

--
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Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Alexander Bokovoy 

On Thu, 23 Jul 2015, Christian Heimes wrote:

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:


from M2Crypto import RC4
from ipaserver.dcerpc import arcfour_encrypt
RC4.RC4(b'key').update(b'data')

'o\r@\x8c'

arcfour_encrypt(b'key', b'data')

Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:


arcfour_encrypt(b'key12', b'data')

'\xcd\xf80d'

RC4.RC4(b'key12').update(b'data')

'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148



From da4aa9baa932e335ad0bd0f3cfe2551667c7ca76 Mon Sep 17 00:00:00 2001
From: Christian Heimes chei...@redhat.com
Date: Tue, 21 Jul 2015 15:18:40 +0200
Subject: [PATCH] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:


from M2Crypto import RC4
from ipaserver.dcerpc import arcfour_encrypt
RC4.RC4(b'key').update(b'data')

'o\r@\x8c'

arcfour_encrypt(b'key', b'data')

Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:


arcfour_encrypt(b'key12', b'data')

'\xcd\xf80d'

RC4.RC4(b'key12').update(b'data')

'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148
---
freeipa.spec.in |  1 +
ipaserver/dcerpc.py | 15 ++-
2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/freeipa.spec.in b/freeipa.spec.in
index 
fef20e1f7e6fde9b90851a2686e515a6a779f954..afae22430515a9f15eced9e16e0a6e192400e6e2
 100644
--- a/freeipa.spec.in
+++ b/freeipa.spec.in
@@ -150,6 +150,7 @@ Requires(preun): python systemd-units
Requires(postun): python systemd-units
Requires: python-dns = 1.11.1
Requires: python-kdcproxy = 0.3
+Requires: python-cryptography
Requires: zip
Requires: policycoreutils = 2.1.12-5
Requires: tar
diff --git a/ipaserver/dcerpc.py b/ipaserver/dcerpc.py
index 
4de5afb540e880e8948749c2cfa9a019eb807c47..578b3ee209ee988bca4d75bd5b898f339625236c
 100644
--- a/ipaserver/dcerpc.py
+++ b/ipaserver/dcerpc.py
@@ -42,7 +42,8 @@ from samba.ndr import ndr_pack, ndr_print
from samba import net
import samba
import random
-from M2Crypto import RC4
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms
+from cryptography.hazmat.backends import default_backend
try:
from ldap.controls import RequestControl as LDAPControl #pylint: 
disable=F0401
except ImportError:
@@ -120,6 +121,14 @@ def assess_dcerpc_exception(num=None,message=None):
  message %(message)s (both may be None)''') % 
dict(num=num, message=message)
return errors.RemoteRetrieveError(reason=reason)

+
+def arcfour_encrypt(key, data):
+algorithm = algorithms.ARC4(key)
+cipher = Cipher(algorithm, mode=None, backend=default_backend())
+encryptor = cipher.encryptor()
+return encryptor.update(data)
+
+
class ExtendedDNControl(LDAPControl):
# This class attempts to implement LDAP control that would work
# with both python-ldap 2.4.x and 2.3.x, thus there is mix of properties
@@ -910,10 +919,6 @@ class TrustDomainInstance(object):
self.info['is_pdc'] = (result.role == lsa.LSA_ROLE_PRIMARY)

def generate_auth(self, trustdom_secret):
-def arcfour_encrypt(key, data):
-c = RC4.RC4(key)
-return c.update(data)
-
password_blob = string_to_array(trustdom_secret.encode('utf-16-le'))

clear_value = drsblobs.AuthInfoClear()
--
2.4.3


ACK. Tested by re-establishing trust to AD.


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Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Jan Cholasta 

Hi,

Dne 23.7.2015 v 10:43 Christian Heimes napsal(a):

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:


from M2Crypto import RC4
from ipaserver.dcerpc import arcfour_encrypt
RC4.RC4(b'key').update(b'data')

'o\r@\x8c'

arcfour_encrypt(b'key', b'data')

Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:


arcfour_encrypt(b'key12', b'data')

'\xcd\xf80d'

RC4.RC4(b'key12').update(b'data')

'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148


NACK on the spec file change. There is a BuildRequires and Requires on 
m2crypto, replace them with BuildRequires and Requires on 
python-cryptography.


Honza

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Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Christian Heimes 
On 2015-07-23 10:54, Jan Cholasta wrote:
 Hi,
 
 Dne 23.7.2015 v 10:43 Christian Heimes napsal(a):
 This patch removes the dependency on M2Crypto in favor for cryptography.
 Cryptography is more strict about the key size and doesn't support
 non-standard key sizes:

 from M2Crypto import RC4
 from ipaserver.dcerpc import arcfour_encrypt
 RC4.RC4(b'key').update(b'data')
 'o\r@\x8c'
 arcfour_encrypt(b'key', b'data')
 Traceback (most recent call last):
 ...
 ValueError: Invalid key size (24) for RC4.

 Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

 arcfour_encrypt(b'key12', b'data')
 '\xcd\xf80d'
 RC4.RC4(b'key12').update(b'data')
 '\xcd\xf80d'

 http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4

 https://fedorahosted.org/freeipa/ticket/5148
 
 NACK on the spec file change. There is a BuildRequires and Requires on
 m2crypto, replace them with BuildRequires and Requires on
 python-cryptography.

Argh, m2crypto ... I was looking for M2Crypto (case sensitive). Here is
an updated patch.

An additional Requires: python-cryptography is not required.
server-trust-ad depends on ipa-server which depends on the ipa-python
package. The ipa-python package already has Requires: python-cryptography.

Christian

From d0a6ab9f9c0723af7ca027fd3522a063428b7f34 Mon Sep 17 00:00:00 2001
From: Christian Heimes chei...@redhat.com
Date: Tue, 21 Jul 2015 15:18:40 +0200
Subject: [PATCH] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:

 from M2Crypto import RC4
 from ipaserver.dcerpc import arcfour_encrypt
 RC4.RC4(b'key').update(b'data')
'o\r@\x8c'
 arcfour_encrypt(b'key', b'data')
Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

 arcfour_encrypt(b'key12', b'data')
'\xcd\xf80d'
 RC4.RC4(b'key12').update(b'data')
'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148
---
 freeipa.spec.in |  2 --
 ipaserver/dcerpc.py | 15 ++-
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/freeipa.spec.in b/freeipa.spec.in
index fef20e1f7e6fde9b90851a2686e515a6a779f954..bf04582de949e6fe8ae34ea5a96f32598247aa7e 100644
--- a/freeipa.spec.in
+++ b/freeipa.spec.in
@@ -84,7 +84,6 @@ BuildRequires:  python-lxml
 BuildRequires:  python-pyasn1 = 0.0.9a
 BuildRequires:  python-qrcode-core = 5.0.0
 BuildRequires:  python-dns = 1.11.1
-BuildRequires:  m2crypto
 BuildRequires:  check
 BuildRequires:  libsss_idmap-devel
 BuildRequires:  libsss_nss_idmap-devel = 1.12.2
@@ -219,7 +218,6 @@ Integrated DNS server is BIND 9. OpenDNSSEC provides key management.
 Summary: Virtual package to install packages required for Active Directory trusts
 Group: System Environment/Base
 Requires: %{name}-server = %version-%release
-Requires: m2crypto
 Requires: samba-python
 Requires: samba = %{samba_version}
 Requires: samba-winbind
diff --git a/ipaserver/dcerpc.py b/ipaserver/dcerpc.py
index 4de5afb540e880e8948749c2cfa9a019eb807c47..578b3ee209ee988bca4d75bd5b898f339625236c 100644
--- a/ipaserver/dcerpc.py
+++ b/ipaserver/dcerpc.py
@@ -42,7 +42,8 @@ from samba.ndr import ndr_pack, ndr_print
 from samba import net
 import samba
 import random
-from M2Crypto import RC4
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms
+from cryptography.hazmat.backends import default_backend
 try:
 from ldap.controls import RequestControl as LDAPControl #pylint: disable=F0401
 except ImportError:
@@ -120,6 +121,14 @@ def assess_dcerpc_exception(num=None,message=None):
   message %(message)s (both may be None)''') % dict(num=num, message=message)
 return errors.RemoteRetrieveError(reason=reason)
 
+
+def arcfour_encrypt(key, data):
+algorithm = algorithms.ARC4(key)
+cipher = Cipher(algorithm, mode=None, backend=default_backend())
+encryptor = cipher.encryptor()
+return encryptor.update(data)
+
+
 class ExtendedDNControl(LDAPControl):
 # This class attempts to implement LDAP control that would work
 # with both python-ldap 2.4.x and 2.3.x, thus there is mix of properties
@@ -910,10 +919,6 @@ class TrustDomainInstance(object):
 self.info['is_pdc'] = (result.role == lsa.LSA_ROLE_PRIMARY)
 
 def generate_auth(self, trustdom_secret):
-def arcfour_encrypt(key, data):
-c = RC4.RC4(key)
-return c.update(data)
-
 password_blob = string_to_array(trustdom_secret.encode('utf-16-le'))
 
 clear_value = drsblobs.AuthInfoClear()
-- 
2.4.3



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Re: [Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Alexander Bokovoy 

On Thu, 23 Jul 2015, Christian Heimes wrote:

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:


from M2Crypto import RC4
from ipaserver.dcerpc import arcfour_encrypt
RC4.RC4(b'key').update(b'data')

'o\r@\x8c'

arcfour_encrypt(b'key', b'data')

Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:


arcfour_encrypt(b'key12', b'data')

'\xcd\xf80d'

RC4.RC4(b'key12').update(b'data')

'\xcd\xf80d'

Note that we are using NTLMv2 or Kerberos user session keys which are
128 bit long in this context.

And please rework the spec file change as Honza noted.
--
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[Freeipa-devel] [PATCH 0014] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

2015-07-23 Thread Christian Heimes 
This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:

 from M2Crypto import RC4
 from ipaserver.dcerpc import arcfour_encrypt
 RC4.RC4(b'key').update(b'data')
'o\r@\x8c'
 arcfour_encrypt(b'key', b'data')
Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

 arcfour_encrypt(b'key12', b'data')
'\xcd\xf80d'
 RC4.RC4(b'key12').update(b'data')
'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148
From da4aa9baa932e335ad0bd0f3cfe2551667c7ca76 Mon Sep 17 00:00:00 2001
From: Christian Heimes chei...@redhat.com
Date: Tue, 21 Jul 2015 15:18:40 +0200
Subject: [PATCH] [py3] Replace M2Crypto RC4 with python-cryptography ARC4

This patch removes the dependency on M2Crypto in favor for cryptography.
Cryptography is more strict about the key size and doesn't support
non-standard key sizes:

 from M2Crypto import RC4
 from ipaserver.dcerpc import arcfour_encrypt
 RC4.RC4(b'key').update(b'data')
'o\r@\x8c'
 arcfour_encrypt(b'key', b'data')
Traceback (most recent call last):
...
ValueError: Invalid key size (24) for RC4.

Standard key sizes 40, 56, 64, 80, 128, 192 and 256 are supported:

 arcfour_encrypt(b'key12', b'data')
'\xcd\xf80d'
 RC4.RC4(b'key12').update(b'data')
'\xcd\xf80d'

http://cryptography.readthedocs.org/en/latest/hazmat/primitives/symmetric-encryption/#cryptography.hazmat.primitives.ciphers.algorithms.ARC4
https://fedorahosted.org/freeipa/ticket/5148
---
 freeipa.spec.in |  1 +
 ipaserver/dcerpc.py | 15 ++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/freeipa.spec.in b/freeipa.spec.in
index fef20e1f7e6fde9b90851a2686e515a6a779f954..afae22430515a9f15eced9e16e0a6e192400e6e2 100644
--- a/freeipa.spec.in
+++ b/freeipa.spec.in
@@ -150,6 +150,7 @@ Requires(preun): python systemd-units
 Requires(postun): python systemd-units
 Requires: python-dns = 1.11.1
 Requires: python-kdcproxy = 0.3
+Requires: python-cryptography
 Requires: zip
 Requires: policycoreutils = 2.1.12-5
 Requires: tar
diff --git a/ipaserver/dcerpc.py b/ipaserver/dcerpc.py
index 4de5afb540e880e8948749c2cfa9a019eb807c47..578b3ee209ee988bca4d75bd5b898f339625236c 100644
--- a/ipaserver/dcerpc.py
+++ b/ipaserver/dcerpc.py
@@ -42,7 +42,8 @@ from samba.ndr import ndr_pack, ndr_print
 from samba import net
 import samba
 import random
-from M2Crypto import RC4
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms
+from cryptography.hazmat.backends import default_backend
 try:
 from ldap.controls import RequestControl as LDAPControl #pylint: disable=F0401
 except ImportError:
@@ -120,6 +121,14 @@ def assess_dcerpc_exception(num=None,message=None):
   message %(message)s (both may be None)''') % dict(num=num, message=message)
 return errors.RemoteRetrieveError(reason=reason)
 
+
+def arcfour_encrypt(key, data):
+algorithm = algorithms.ARC4(key)
+cipher = Cipher(algorithm, mode=None, backend=default_backend())
+encryptor = cipher.encryptor()
+return encryptor.update(data)
+
+
 class ExtendedDNControl(LDAPControl):
 # This class attempts to implement LDAP control that would work
 # with both python-ldap 2.4.x and 2.3.x, thus there is mix of properties
@@ -910,10 +919,6 @@ class TrustDomainInstance(object):
 self.info['is_pdc'] = (result.role == lsa.LSA_ROLE_PRIMARY)
 
 def generate_auth(self, trustdom_secret):
-def arcfour_encrypt(key, data):
-c = RC4.RC4(key)
-return c.update(data)
-
 password_blob = string_to_array(trustdom_secret.encode('utf-16-le'))
 
 clear_value = drsblobs.AuthInfoClear()
-- 
2.4.3



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