import pam
from django.contrib.auth.models import User

class PamBackend:
        def authenticate(self, username=None, password=None):
        # Check the username/password and return a User.
                if pam.authenticate(username, password, service='login'):
                        try:
                                return User.objects.get(username=username)
                        except User.DoesNotExist:
                                pass
                return None