Produits Entr'ouvert » Authentic 2

include src/authentic2/vendor/dpam/LICENSE

.. _auth_pam:

======================================

Authentication on Authentic 2 with PAM

======================================

This module is copied from https://bitbucket.org/wnielson/django-pam/ by Weston

Nielson and the pam ctype module by Chris Atlee http://atlee.ca/software/pam/.

Add 'authentic2.vendor.dpam.backends.PAMBackend' to your

``settings.py``::

  AUTHENTICATION_BACKENDS = (

      ...

      'authentic2.vendor.dpam.backends.PAMBackend',

      ...

  )

Now you can login via the system-login credentials.  If the user is

successfully authenticated but has never logged-in before, a new ``User``

object is created.  By default this new ``User`` has both ``is_staff`` and

``is_superuser`` set to ``False``.  You can change this behavior by adding

``PAM_IS_STAFF=True`` and ``PAM_IS_SUPERUSER`` in your ``settings.py`` file.

The default PAM service used is ``login`` but you can change it by setting the

``PAM_SERVICE`` variable in your ``settings.py`` file.

    auth_pam

    quick_pam

.. _quick_pam:

=================================

Quickstart for PAM Authentication

=================================

This module is copied from https://bitbucket.org/wnielson/django-pam/ by Weston

Nielson and the pam ctype module by Chris Atlee http://atlee.ca/software/pam/.

Add 'authentic2.vendor.dpam.backends.PAMBackend' to your

``settings.py``::

  AUTHENTICATION_BACKENDS = (

      ...

      'authentic2.vendor.dpam.backends.PAMBackend',

      ...

  )

Now you can login via the system-login credentials.  If the user is

successfully authenticated but has never logged-in before, a new ``User``

object is created.  By default this new ``User`` has both ``is_staff`` and

``is_superuser`` set to ``False``.  You can change this behavior by adding

``PAM_IS_STAFF=True`` and ``PAM_IS_SUPERUSER`` in your ``settings.py`` file.

The default PAM service used is ``login`` but you can change it by setting the

``PAM_SERVICE`` variable in your ``settings.py`` file.

import sys

import os

# vendor contains incorporated dependencies

sys.path.append(os.path.join(os.path.dirname(__file__), 'vendor'))

Copyright (c) 2011, Weston Nielson <wnielson@gmail.com>

2All rights reserved.

3

4Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

5

6Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

7Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

8THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import pam

import logging

from django.conf import settings

from authentic2.backends import is_user_authenticable

from authentic2.compat import get_user_model

logger = logging.getLogger(__name__)

class PAMBackend:

    def authenticate(self, username=None, password=None):

        User = get_user_model()

        service = getattr(settings, 'PAM_SERVICE', 'login')

        if pam.authenticate(username, password, service=service):

            try:

                user = User.objects.get(username=username)

            except:

                user = User(username=username, password='not stored here')

                if getattr(settings, 'PAM_IS_SUPERUSER', False):

                    user.is_superuser = True

                if getattr(settings, 'PAM_IS_STAFF', user.is_superuser):

                    user.is_staff = True

                user.save()

            if not is_user_authenticable(user):

                logger.info(u'auth_pam: authentication refused by user filters')

                return None

            return user

        return None

    def get_user(self, user_id):

        User = get_user_model()

        try:

            return User.objects.get(pk=user_id)

        except User.DoesNotExist:

            return None

# (c) 2007 Chris AtLee <chris@atlee.ca>

# Licensed under the MIT license:

# http://www.opensource.org/licenses/mit-license.php

"""

PAM module for python

Provides an authenticate function that will allow the caller to authenticate

a user against the Pluggable Authentication Modules (PAM) on the system.

Implemented using ctypes, so no compilation is necessary.

"""

__all__ = ['authenticate']

from ctypes import CDLL, POINTER, Structure, CFUNCTYPE, cast, pointer, sizeof

from ctypes import c_void_p, c_uint, c_char_p, c_char, c_int

from ctypes.util import find_library

LIBPAM = CDLL(find_library("pam"))

LIBC = CDLL(find_library("c"))

CALLOC = LIBC.calloc

CALLOC.restype = c_void_p

CALLOC.argtypes = [c_uint, c_uint]

STRDUP = LIBC.strdup

STRDUP.argstypes = [c_char_p]

STRDUP.restype = POINTER(c_char) # NOT c_char_p !!!!

# Various constants

PAM_PROMPT_ECHO_OFF = 1

PAM_PROMPT_ECHO_ON = 2

PAM_ERROR_MSG = 3

PAM_TEXT_INFO = 4

class PamHandle(Structure):

    """wrapper class for pam_handle_t"""

    _fields_ = [

            ("handle", c_void_p)

            ]

    def __init__(self):

        Structure.__init__(self)

        self.handle = 0

class PamMessage(Structure):

    """wrapper class for pam_message structure"""

    _fields_ = [

            ("msg_style", c_int),

            ("msg", c_char_p),

            ]

    def __repr__(self):

        return "<PamMessage %i '%s'>" % (self.msg_style, self.msg)

class PamResponse(Structure):

    """wrapper class for pam_response structure"""

    _fields_ = [

            ("resp", c_char_p),

            ("resp_retcode", c_int),

            ]

    def __repr__(self):

        return "<PamResponse %i '%s'>" % (self.resp_retcode, self.resp)

CONV_FUNC = CFUNCTYPE(c_int,

        c_int, POINTER(POINTER(PamMessage)),

               POINTER(POINTER(PamResponse)), c_void_p)

class PamConv(Structure):

    """wrapper class for pam_conv structure"""

    _fields_ = [

            ("conv", CONV_FUNC),

            ("appdata_ptr", c_void_p)

            ]

PAM_START = LIBPAM.pam_start

PAM_START.restype = c_int

PAM_START.argtypes = [c_char_p, c_char_p, POINTER(PamConv),

        POINTER(PamHandle)]

PAM_AUTHENTICATE = LIBPAM.pam_authenticate

PAM_AUTHENTICATE.restype = c_int

PAM_AUTHENTICATE.argtypes = [PamHandle, c_int]

def authenticate(username, password, service='login'):

    """Returns True if the given username and password authenticate for the

    given service.  Returns False otherwise

    ``username``: the username to authenticate

    ``password``: the password in plain text

    ``service``: the PAM service to authenticate against.

                 Defaults to 'login'"""

    @CONV_FUNC

    def my_conv(n_messages, messages, p_response, app_data):

        """Simple conversation function that responds to any

        prompt where the echo is off with the supplied password"""

        # Create an array of n_messages response objects

        addr = CALLOC(n_messages, sizeof(PamResponse))

        p_response[0] = cast(addr, POINTER(PamResponse))

        for i in range(n_messages):

            if messages[i].contents.msg_style == PAM_PROMPT_ECHO_OFF:

                pw_copy = STRDUP(str(password))

                p_response.contents[i].resp = cast(pw_copy, c_char_p)

                p_response.contents[i].resp_retcode = 0

        return 0

    handle = PamHandle()

    conv = PamConv(my_conv, 0)

    retval = PAM_START(service, username, pointer(conv), pointer(handle))

    if retval != 0:

        # TODO: This is not an authentication error, something

        # has gone wrong starting up PAM

        return False

    retval = PAM_AUTHENTICATE(handle, 0)

    return retval == 0

if __name__ == "__main__":

    import getpass

    print authenticate(getpass.getuser(), getpass.getpass())

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