keystone/keystone/auth/plugins/external.py

# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2013 OpenStack Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

"""Keystone External Authentication Plugins"""

import abc

import six

from keystone import auth
from keystone.common import config
from keystone import exception
from keystone.openstack.common import log
from keystone.openstack.common import versionutils


LOG = log.getLogger(__name__)

CONF = config.CONF


@six.add_metaclass(abc.ABCMeta)
class Base(auth.AuthMethodHandler):
    def authenticate(self, context, auth_info, auth_context):
        """Use REMOTE_USER to look up the user in the identity backend.

        auth_context is an in-out variable that will be updated with the
        user_id from the actual user from the REMOTE_USER env variable.
        """
        try:
            REMOTE_USER = context['environment']['REMOTE_USER']
        except KeyError:
            msg = _('No authenticated user')
            raise exception.Unauthorized(msg)
        try:
            user_ref = self._authenticate(REMOTE_USER, context, auth_info)
            auth_context['user_id'] = user_ref['id']
            if ('kerberos' in CONF.token.bind and
                (context['environment'].get('AUTH_TYPE', '').lower()
                 == 'negotiate')):
                auth_context['bind']['kerberos'] = user_ref['name']
        except Exception:
            msg = _('Unable to lookup user %s') % (REMOTE_USER)
            raise exception.Unauthorized(msg)

    @abc.abstractmethod
    def _authenticate(self, remote_user, context, auth_info):
        """Look up the user in the identity backend.

        Return user_ref
        """
        pass


class DefaultDomain(Base):
    def _authenticate(self, remote_user, context, auth_info):
        """Use remote_user to look up the user in the identity backend."""
        domain_id = CONF.identity.default_domain_id
        user_ref = auth_info.identity_api.get_user_by_name(remote_user,
                                                           domain_id)
        return user_ref


class Domain(Base):
    def _authenticate(self, remote_user, context, auth_info):
        """Use remote_user to look up the user in the identity backend.

        The domain will be extracted from the REMOTE_DOMAIN environment
        variable if present. If not, the default domain will be used.
        """

        username = remote_user
        try:
            domain_name = context['environment']['REMOTE_DOMAIN']
        except KeyError:
            domain_id = CONF.identity.default_domain_id
        else:
            domain_ref = (auth_info.identity_api.
                          get_domain_by_name(domain_name))
            domain_id = domain_ref['id']

        user_ref = auth_info.identity_api.get_user_by_name(username,
                                                           domain_id)
        return user_ref


class ExternalDefault(DefaultDomain):
    """Deprecated. Please use keystone.auth.external.DefaultDomain instead."""

    @versionutils.deprecated(
        as_of=versionutils.deprecated.ICEHOUSE,
        in_favor_of='keystone.auth.external.DefaultDomain',
        remove_in=+1)
    def __init__(self):
        super(ExternalDefault, self).__init__()


class ExternalDomain(Domain):
    """Deprecated. Please use keystone.auth.external.Domain instead."""

    @versionutils.deprecated(
        as_of=versionutils.deprecated.ICEHOUSE,
        in_favor_of='keystone.auth.external.Domain',
        remove_in=+1)
    def __init__(self):
        super(ExternalDomain, self).__init__()


class LegacyDefaultDomain(Base):
    """Deprecated. Please use keystone.auth.external.DefaultDomain instead.

    This plugin exists to provide compatibility for the unintended behavior
    described here: https://bugs.launchpad.net/keystone/+bug/1253484

    """

    @versionutils.deprecated(
        as_of=versionutils.deprecated.ICEHOUSE,
        in_favor_of='keystone.auth.external.DefaultDomain',
        remove_in=+1)
    def __init__(self):
        super(LegacyDefaultDomain, self).__init__()

    def _authenticate(self, remote_user, context, auth_info):
        """Use remote_user to look up the user in the identity backend."""
        # NOTE(dolph): this unintentionally discards half the REMOTE_USER value
        names = remote_user.split('@')
        username = names.pop(0)
        domain_id = CONF.identity.default_domain_id
        user_ref = auth_info.identity_api.get_user_by_name(username,
                                                           domain_id)
        return user_ref


class LegacyDomain(Base):
    """Deprecated. Please use keystone.auth.external.Domain instead."""

    @versionutils.deprecated(
        as_of=versionutils.deprecated.ICEHOUSE,
        in_favor_of='keystone.auth.external.Domain',
        remove_in=+1)
    def __init__(self):
        super(LegacyDomain, self).__init__()

    def _authenticate(self, remote_user, context, auth_info):
        """Use remote_user to look up the user in the identity backend.

        If remote_user contains an `@` assume that the substring before the
        rightmost `@` is the username, and the substring after the @ is the
        domain name.
        """
        names = remote_user.rsplit('@', 1)
        username = names.pop(0)
        if names:
            domain_name = names[0]
            domain_ref = (auth_info.assignment_api.
                          get_domain_by_name(domain_name))
            domain_id = domain_ref['id']
        else:
            domain_id = CONF.identity.default_domain_id
        user_ref = auth_info.identity_api.get_user_by_name(username,
                                                           domain_id)
        return user_ref