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swift/swift/common/middleware/keystoneauth.py

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# Copyright 2012 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.
from swift.common import utils as swift_utils
from swift.common.http import is_success
from swift.common.middleware import acl as swift_acl
from swift.common.request_helpers import get_sys_meta_prefix
from swift.common.swob import HTTPNotFound, HTTPForbidden, HTTPUnauthorized
from swift.common.utils import config_read_reseller_options, list_from_csv
from swift.proxy.controllers.base import get_account_info
import functools
PROJECT_DOMAIN_ID_HEADER = 'x-account-project-domain-id'
PROJECT_DOMAIN_ID_SYSMETA_HEADER = \
get_sys_meta_prefix('account') + 'project-domain-id'
# a string that is unique w.r.t valid ids
UNKNOWN_ID = '_unknown'
class KeystoneAuth(object):
"""Swift middleware to Keystone authorization system.
In Swift's proxy-server.conf add this keystoneauth middleware and the
authtoken middleware to your pipeline. Make sure you have the authtoken
middleware before the keystoneauth middleware.
The authtoken middleware will take care of validating the user and
keystoneauth will authorize access.
The sample proxy-server.conf shows a sample pipeline that uses keystone.
:download:`proxy-server.conf-sample </../../etc/proxy-server.conf-sample>`
The authtoken middleware is shipped with keystonemiddleware - it
does not have any other dependencies than itself so you can either
install it by copying the file directly in your python path or by
installing keystonemiddleware.
If support is required for unvalidated users (as with anonymous
access) or for formpost/staticweb/tempurl middleware, authtoken will
need to be configured with ``delay_auth_decision`` set to true. See
the Keystone documentation for more detail on how to configure the
authtoken middleware.
In proxy-server.conf you will need to have the setting account
auto creation to true::
[app:proxy-server]
account_autocreate = true
And add a swift authorization filter section, such as::
[filter:keystoneauth]
use = egg:swift#keystoneauth
operator_roles = admin, swiftoperator
The user who is able to give ACL / create Containers permissions
will be the user with a role listed in the ``operator_roles``
setting which by default includes the admin and the swiftoperator
roles.
The keystoneauth middleware maps a Keystone project/tenant to an account
in Swift by adding a prefix (``AUTH_`` by default) to the tenant/project
id.. For example, if the project id is ``1234``, the path is
``/v1/AUTH_1234``.
If you need to have a different reseller_prefix to be able to
mix different auth servers you can configure the option
``reseller_prefix`` in your keystoneauth entry like this::
reseller_prefix = NEWAUTH
Don't forget to also update the Keystone service endpoint configuration to
use NEWAUTH in the path.
It is possible to have several accounts associated with the same project.
This is done by listing several prefixes as shown in the following
example::
reseller_prefix = AUTH, SERVICE
This means that for project id '1234', the paths '/v1/AUTH_1234' and
'/v1/SERVICE_1234' are associated with the project and are authorized
using roles that a user has with that project. The core use of this feature
is that it is possible to provide different rules for each account
prefix. The following parameters may be prefixed with the appropriate
prefix::
operator_roles
service_roles
For backward compatibility, if either of these parameters is specified
without a prefix then it applies to all reseller_prefixes. Here is an
example, using two prefixes::
reseller_prefix = AUTH, SERVICE
# The next three lines have identical effects (since the first applies
# to both prefixes).
operator_roles = admin, swiftoperator
AUTH_operator_roles = admin, swiftoperator
SERVICE_operator_roles = admin, swiftoperator
# The next line only applies to accounts with the SERVICE prefix
SERVICE_operator_roles = admin, some_other_role
X-Service-Token tokens are supported by the inclusion of the service_roles
configuration option. When present, this option requires that the
X-Service-Token header supply a token from a user who has a role listed
in service_roles. Here is an example configuration::
reseller_prefix = AUTH, SERVICE
AUTH_operator_roles = admin, swiftoperator
SERVICE_operator_roles = admin, swiftoperator
SERVICE_service_roles = service
The keystoneauth middleware supports cross-tenant access control using the
syntax ``<tenant>:<user>`` to specify a grantee in container Access Control
Lists (ACLs). For a request to be granted by an ACL, the grantee
``<tenant>`` must match the UUID of the tenant to which the request
X-Auth-Token is scoped and the grantee ``<user>`` must match the UUID of
the user authenticated by that token.
Note that names must no longer be used in cross-tenant ACLs because with
the introduction of domains in keystone names are no longer globally
unique.
For backwards compatibility, ACLs using names will be granted by
keystoneauth when it can be established that the grantee tenant,
the grantee user and the tenant being accessed are either not yet in a
domain (e.g. the X-Auth-Token has been obtained via the keystone v2
API) or are all in the default domain to which legacy accounts would
have been migrated. The default domain is identified by its UUID,
which by default has the value ``default``. This can be changed by
setting the ``default_domain_id`` option in the keystoneauth
configuration::
default_domain_id = default
The backwards compatible behavior can be disabled by setting the config
option ``allow_names_in_acls`` to false::
allow_names_in_acls = false
To enable this backwards compatibility, keystoneauth will attempt to
determine the domain id of a tenant when any new account is created,
and persist this as account metadata. If an account is created for a tenant
using a token with reselleradmin role that is not scoped on that tenant,
keystoneauth is unable to determine the domain id of the tenant;
keystoneauth will assume that the tenant may not be in the default domain
and therefore not match names in ACLs for that account.
By default, middleware higher in the WSGI pipeline may override auth
processing, useful for middleware such as tempurl and formpost. If you know
you're not going to use such middleware and you want a bit of extra
security you can disable this behaviour by setting the ``allow_overrides``
option to ``false``::
allow_overrides = false
:param app: The next WSGI app in the pipeline
:param conf: The dict of configuration values
"""
def __init__(self, app, conf):
self.app = app
self.conf = conf
self.logger = swift_utils.get_logger(conf, log_route='keystoneauth')
self.reseller_prefixes, self.account_rules = \
config_read_reseller_options(conf,
dict(operator_roles=['admin',
'swiftoperator'],
service_roles=[],
project_reader_roles=[]))
self.reseller_admin_role = conf.get('reseller_admin_role',
'ResellerAdmin').lower()
self.system_reader_roles = {role.lower() for role in list_from_csv(
conf.get('system_reader_roles', ''))}
config_is_admin = conf.get('is_admin', "false").lower()
if swift_utils.config_true_value(config_is_admin):
self.logger.warning("The 'is_admin' option for keystoneauth is no "
"longer supported. Remove the 'is_admin' "
"option from your keystoneauth config")
config_overrides = conf.get('allow_overrides', 't').lower()
self.allow_overrides = swift_utils.config_true_value(config_overrides)
self.default_domain_id = conf.get('default_domain_id', 'default')
self.allow_names_in_acls = swift_utils.config_true_value(
conf.get('allow_names_in_acls', 'true'))
def __call__(self, environ, start_response):
env_identity = self._keystone_identity(environ)
# Check if one of the middleware like tempurl or formpost have
# set the swift.authorize_override environ and want to control the
# authentication
if (self.allow_overrides and
environ.get('swift.authorize_override', False)):
msg = 'Authorizing from an overriding middleware'
self.logger.debug(msg)
return self.app(environ, start_response)
if env_identity:
self.logger.debug('Using identity: %r', env_identity)
environ['REMOTE_USER'] = env_identity.get('tenant')
environ['keystone.identity'] = env_identity
environ['swift.authorize'] = functools.partial(
self.authorize, env_identity)
user_roles = (r.lower() for r in env_identity.get('roles', []))
if self.reseller_admin_role in user_roles:
environ['reseller_request'] = True
else:
self.logger.debug('Authorizing as anonymous')
environ['swift.authorize'] = self.authorize_anonymous
environ['swift.clean_acl'] = swift_acl.clean_acl
def keystone_start_response(status, response_headers, exc_info=None):
project_domain_id = None
for key, val in response_headers:
if key.lower() == PROJECT_DOMAIN_ID_SYSMETA_HEADER:
project_domain_id = val
break
if project_domain_id:
response_headers.append((PROJECT_DOMAIN_ID_HEADER,
project_domain_id))
return start_response(status, response_headers, exc_info)
return self.app(environ, keystone_start_response)
def _keystone_identity(self, environ):
"""Extract the identity from the Keystone auth component."""
if (environ.get('HTTP_X_IDENTITY_STATUS') != 'Confirmed'
or environ.get(
'HTTP_X_SERVICE_IDENTITY_STATUS') not in (None, 'Confirmed')):
return
roles = list_from_csv(environ.get('HTTP_X_ROLES', ''))
service_roles = list_from_csv(environ.get('HTTP_X_SERVICE_ROLES', ''))
identity = {'user': (environ.get('HTTP_X_USER_ID'),
environ.get('HTTP_X_USER_NAME')),
'tenant': (environ.get('HTTP_X_PROJECT_ID',
environ.get('HTTP_X_TENANT_ID')),
environ.get('HTTP_X_PROJECT_NAME',
environ.get('HTTP_X_TENANT_NAME'))),
'roles': roles,
'service_roles': service_roles}
token_info = environ.get('keystone.token_info', {})
auth_version = 0
user_domain = project_domain = (None, None)
if 'access' in token_info:
# ignore any domain id headers that authtoken may have set
auth_version = 2
elif 'token' in token_info:
auth_version = 3
user_domain = (environ.get('HTTP_X_USER_DOMAIN_ID'),
environ.get('HTTP_X_USER_DOMAIN_NAME'))
project_domain = (environ.get('HTTP_X_PROJECT_DOMAIN_ID'),
environ.get('HTTP_X_PROJECT_DOMAIN_NAME'))
identity['user_domain'] = user_domain
identity['project_domain'] = project_domain
identity['auth_version'] = auth_version
return identity
def _get_account_name(self, prefix, tenant_id):
return '%s%s' % (prefix, tenant_id)
def _account_matches_tenant(self, account, tenant_id):
"""Check if account belongs to a project/tenant"""
for prefix in self.reseller_prefixes:
if self._get_account_name(prefix, tenant_id) == account:
return True
return False
def _get_account_prefix(self, account):
"""Get the prefix of an account"""
# Empty prefix matches everything, so try to match others first
for prefix in [pre for pre in self.reseller_prefixes if pre != '']:
if account.startswith(prefix):
return prefix
if '' in self.reseller_prefixes:
return ''
return None
def _get_project_domain_id(self, environ):
info = get_account_info(environ, self.app, 'KS')
domain_id = info.get('sysmeta', {}).get('project-domain-id')
exists = (is_success(info.get('status', 0))
and info.get('account_really_exists', True))
return exists, domain_id
def _set_project_domain_id(self, req, path_parts, env_identity):
'''
Try to determine the project domain id and save it as
account metadata. Do this for a PUT or POST to the
account, and also for a container PUT in case that
causes the account to be auto-created.
'''
if PROJECT_DOMAIN_ID_SYSMETA_HEADER in req.headers:
return
version, account, container, obj = path_parts
method = req.method
if (obj or (container and method != 'PUT')
or method not in ['PUT', 'POST']):
return
tenant_id, tenant_name = env_identity['tenant']
exists, sysmeta_id = self._get_project_domain_id(req.environ)
req_has_id, req_id, new_id = False, None, None
if self._account_matches_tenant(account, tenant_id):
# domain id can be inferred from request (may be None)
req_has_id = True
req_id = env_identity['project_domain'][0]
if not exists:
# new account so set a domain id
new_id = req_id if req_has_id else UNKNOWN_ID
elif sysmeta_id is None and req_id == self.default_domain_id:
# legacy account, update if default domain id in req
new_id = req_id
elif sysmeta_id == UNKNOWN_ID and req_has_id:
# unknown domain, update if req confirms domain
new_id = req_id or ''
elif req_has_id and sysmeta_id != req_id:
self.logger.warning("Inconsistent project domain id: " +
"%s in token vs %s in account metadata."
% (req_id, sysmeta_id))
if new_id is not None:
req.headers[PROJECT_DOMAIN_ID_SYSMETA_HEADER] = new_id
def _is_name_allowed_in_acl(self, req, path_parts, identity):
if not self.allow_names_in_acls:
return False
user_domain_id = identity['user_domain'][0]
if user_domain_id and user_domain_id != self.default_domain_id:
return False
proj_domain_id = identity['project_domain'][0]
if proj_domain_id and proj_domain_id != self.default_domain_id:
return False
# request user and scoped project are both in default domain
tenant_id, tenant_name = identity['tenant']
version, account, container, obj = path_parts
if self._account_matches_tenant(account, tenant_id):
# account == scoped project, so account is also in default domain
allow = True
else:
# retrieve account project domain id from account sysmeta
exists, acc_domain_id = self._get_project_domain_id(req.environ)
allow = exists and acc_domain_id in [self.default_domain_id, None]
if allow:
self.logger.debug("Names allowed in acls.")
return allow
def _authorize_cross_tenant(self, user_id, user_name,
tenant_id, tenant_name, roles,
allow_names=True):
"""Check cross-tenant ACLs.
Match tenant:user, tenant and user could be its id, name or '*'
:param user_id: The user id from the identity token.
:param user_name: The user name from the identity token.
:param tenant_id: The tenant ID from the identity token.
:param tenant_name: The tenant name from the identity token.
:param roles: The given container ACL.
:param allow_names: If True then attempt to match tenant and user names
as well as id's.
:returns: matched string if tenant(name/id/*):user(name/id/*) matches
the given ACL.
None otherwise.
"""
tenant_match = [tenant_id, '*']
user_match = [user_id, '*']
if allow_names:
tenant_match = tenant_match + [tenant_name]
user_match = user_match + [user_name]
for tenant in tenant_match:
for user in user_match:
s = '%s:%s' % (tenant, user)
if s in roles:
return s
return None
def authorize(self, env_identity, req):
# Cleanup - make sure that a previously set swift_owner setting is
# cleared now. This might happen for example with COPY requests.
req.environ.pop('swift_owner', None)
tenant_id, tenant_name = env_identity['tenant']
user_id, user_name = env_identity['user']
referrers, roles = swift_acl.parse_acl(getattr(req, 'acl', None))
# allow OPTIONS requests to proceed as normal
if req.method == 'OPTIONS':
return
try:
part = req.split_path(1, 4, True)
version, account, container, obj = part
except ValueError:
return HTTPNotFound(request=req)
self._set_project_domain_id(req, part, env_identity)
user_roles = [r.lower() for r in env_identity.get('roles', [])]
user_service_roles = [r.lower() for r in env_identity.get(
'service_roles', [])]
# Give unconditional access to a user with the reseller_admin role.
if self.reseller_admin_role in user_roles:
msg = 'User %s has reseller admin authorizing'
self.logger.debug(msg, tenant_id)
req.environ['swift_owner'] = True
return
# Being in system_reader_roles is almost as good as reseller_admin.
if self.system_reader_roles.intersection(user_roles):
# Note that if a system reader is trying to write, we're letting
# the request fall on other access checks below. This way,
# a compliance auditor can write a log file as a normal member.
if req.method in ('GET', 'HEAD'):
msg = 'User %s has system reader authorizing'
self.logger.debug(msg, tenant_id)
# We aren't setting 'swift_owner' nor 'reseller_request'
# because they are only ever used for something that modifies
# the contents of the cluster (setting ACL, deleting accounts).
return
# If we are not reseller admin and user is trying to delete its own
# account then deny it.
if not container and not obj and req.method == 'DELETE':
# User is not allowed to issue a DELETE on its own account
msg = 'User %s:%s is not allowed to delete its own account'
self.logger.debug(msg, tenant_name, user_name)
return self.denied_response(req)
# cross-tenant authorization
matched_acl = None
if roles:
allow_names = self._is_name_allowed_in_acl(req, part, env_identity)
matched_acl = self._authorize_cross_tenant(user_id, user_name,
tenant_id, tenant_name,
roles, allow_names)
if matched_acl is not None:
log_msg = 'user %s allowed in ACL authorizing.'
self.logger.debug(log_msg, matched_acl)
return
acl_authorized = self._authorize_unconfirmed_identity(req, obj,
referrers,
roles)
if acl_authorized:
return
# Check if a user tries to access an account that does not match their
# token
if not self._account_matches_tenant(account, tenant_id):
log_msg = 'tenant mismatch: %s != %s'
self.logger.debug(log_msg, account, tenant_id)
return self.denied_response(req)
# Compare roles from tokens against the configuration options:
#
# X-Auth-Token role Has specified X-Service-Token role Grant
# in operator_roles? service_roles? in service_roles? swift_owner?
# ------------------ -------------- -------------------- ------------
# yes yes yes yes
# yes yes no no
# yes no don't care yes
# no don't care don't care no
# ------------------ -------------- -------------------- ------------
account_prefix = self._get_account_prefix(account)
operator_roles = self.account_rules[account_prefix]['operator_roles']
have_operator_role = set(operator_roles).intersection(
set(user_roles))
service_roles = self.account_rules[account_prefix]['service_roles']
have_service_role = set(service_roles).intersection(
set(user_service_roles))
allowed = False
if have_operator_role and (service_roles and have_service_role):
allowed = True
elif have_operator_role and not service_roles:
allowed = True
if allowed:
log_msg = 'allow user with role(s) %s as account admin'
self.logger.debug(log_msg, ','.join(have_operator_role.union(
have_service_role)))
req.environ['swift_owner'] = True
return
# The project_reader_roles is almost as good as operator_roles. But
# it does not work with service tokens and does not get 'swift_owner'.
# And, it only serves GET requests, obviously.
project_reader_roles = self.account_rules[account_prefix][
'project_reader_roles']
have_reader_role = set(project_reader_roles).intersection(
set(user_roles))
if have_reader_role:
if req.method in ('GET', 'HEAD'):
msg = 'User %s with role(s) %s has project reader authorizing'
self.logger.debug(msg, tenant_id,
','.join(project_reader_roles))
return
if acl_authorized is not None:
return self.denied_response(req)
# Check if we have the role in the userroles and allow it
for user_role in user_roles:
if user_role in (r.lower() for r in roles):
log_msg = 'user %s:%s allowed in ACL: %s authorizing'
self.logger.debug(log_msg, tenant_name, user_name,
user_role)
return
return self.denied_response(req)
def authorize_anonymous(self, req):
"""
Authorize an anonymous request.
:returns: None if authorization is granted, an error page otherwise.
"""
try:
part = req.split_path(1, 4, True)
version, account, container, obj = part
except ValueError:
return HTTPNotFound(request=req)
# allow OPTIONS requests to proceed as normal
if req.method == 'OPTIONS':
return
is_authoritative_authz = (account and
(self._get_account_prefix(account) in
self.reseller_prefixes))
if not is_authoritative_authz:
return self.denied_response(req)
referrers, roles = swift_acl.parse_acl(getattr(req, 'acl', None))
authorized = self._authorize_unconfirmed_identity(req, obj, referrers,
roles)
if not authorized:
return self.denied_response(req)
def _authorize_unconfirmed_identity(self, req, obj, referrers, roles):
""""
Perform authorization for access that does not require a
confirmed identity.
:returns: A boolean if authorization is granted or denied. None if
a determination could not be made.
"""
# Allow container sync.
if (req.environ.get('swift_sync_key')
and (req.environ['swift_sync_key'] ==
req.headers.get('x-container-sync-key', None))
and 'x-timestamp' in req.headers):
log_msg = 'allowing proxy %s for container-sync'
self.logger.debug(log_msg, req.remote_addr)
return True
# Check if referrer is allowed.
if swift_acl.referrer_allowed(req.referer, referrers):
if obj or '.rlistings' in roles:
log_msg = 'authorizing %s via referer ACL'
self.logger.debug(log_msg, req.referrer)
return True
return False
def denied_response(self, req):
"""Deny WSGI Response.
Returns a standard WSGI response callable with the status of 403 or 401
depending on whether the REMOTE_USER is set or not.
"""
if req.remote_user:
return HTTPForbidden(request=req)
else:
return HTTPUnauthorized(request=req)
def filter_factory(global_conf, **local_conf):
"""Returns a WSGI filter app for use with paste.deploy."""
conf = global_conf.copy()
conf.update(local_conf)
def auth_filter(app):
return KeystoneAuth(app, conf)
return auth_filter
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