openstack/deb-heat
Code Issues Proposed changes
005b613f8b
deb-heat/heat/common/auth_token.py
Ian Main a5962d1078 Authentication Overhaul 
This patch updates the authentication system set up in heat:

- We now authenticate against the 'heat' service at the entry
  point to each api call in the engine.
- We are now using the 'Context' class to contain the authentication
  information as intended.
- The two context classes are unified and we now use the same one
  for both WSGI and RPC.  This is the intended design as the
  context is loaded by the WSGI middleware and then passed into the
  RPC methods.
- We are now doing token authentication in the API that works with
  both native keystone and AWS style authentication.  That token is
  then passed on to the engine for further authentication for various
  endpoints.

Note that the heat-api-paste.ini file requires updating in order for
this to work on your system.  Admin user and password must be set
properly in the authtoken section in order to perform token based
authentication.

I suspect there will be a few bugs in here yet.  This is just part of
the authentication/identification changes we need to make but I wanted
to get this in so we could continue to work with a boto based client.

Change-Id: Ib635ecd3088304e8d51d8e1fc31a8b1bf751caf3
Signed-off-by: Ian Main <imain@redhat.com>
2012-05-29 16:54:03 -07:00

535 lines
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Python
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010-2012 OpenStack LLC
#
# 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.
"""
TOKEN-BASED AUTH MIDDLEWARE
This WSGI component:
* Verifies that incoming client requests have valid tokens by validating
tokens with the auth service.
* Rejects unauthenticated requests UNLESS it is in 'delay_auth_decision'
mode, which means the final decision is delegated to the downstream WSGI
component (usually the OpenStack service)
* Collects and forwards identity information based on a valid token
such as user name, tenant, etc
Refer to: http://keystone.openstack.org/middlewarearchitecture.html
HEADERS
-------
* Headers starting with HTTP\_ is a standard http header
* Headers starting with HTTP_X is an extended http header
Coming in from initial call from client or customer
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
HTTP_X_AUTH_TOKEN
The client token being passed in.
HTTP_X_STORAGE_TOKEN
The client token being passed in (legacy Rackspace use) to support
swift/cloud files
Used for communication between components
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
WWW-Authenticate
HTTP header returned to a user indicating which endpoint to use
to retrieve a new token
What we add to the request for use by the OpenStack service
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
HTTP_X_IDENTITY_STATUS
'Confirmed' or 'Invalid'
The underlying service will only see a value of 'Invalid' if the Middleware
is configured to run in 'delay_auth_decision' mode
HTTP_X_TENANT_ID
Identity service managed unique identifier, string
HTTP_X_TENANT_NAME
Unique tenant identifier, string
HTTP_X_USER_ID
Identity-service managed unique identifier, string
HTTP_X_USER_NAME
Unique user identifier, string
HTTP_X_ROLES
Comma delimited list of case-sensitive Roles
HTTP_X_TENANT
*Deprecated* in favor of HTTP_X_TENANT_ID and HTTP_X_TENANT_NAME
Keystone-assigned unique identifier, deprecated
HTTP_X_USER
*Deprecated* in favor of HTTP_X_USER_ID and HTTP_X_USER_NAME
Unique user name, string
HTTP_X_ROLE
*Deprecated* in favor of HTTP_X_ROLES
This is being renamed, and the new header contains the same data.
"""
import httplib
import json
import logging
import time
import webob
import webob.exc
LOG = logging.getLogger(__name__)
class InvalidUserToken(Exception):
pass
class ServiceError(Exception):
pass
class AuthProtocol(object):
"""Auth Middleware that handles authenticating client calls."""
def __init__(self, app, conf):
LOG.info('Starting keystone auth_token middleware')
self.conf = conf
self.app = app
# delay_auth_decision means we still allow unauthenticated requests
# through and we let the downstream service make the final decision
self.delay_auth_decision = int(conf.get('delay_auth_decision', 0))
# where to find the auth service (we use this to validate tokens)
self.auth_host = conf.get('auth_host')
self.auth_port = int(conf.get('auth_port', 35357))
auth_protocol = conf.get('auth_protocol', 'https')
if auth_protocol == 'http':
self.http_client_class = httplib.HTTPConnection
else:
self.http_client_class = httplib.HTTPSConnection
default_auth_uri = '%s://%s:%s' % (auth_protocol,
self.auth_host,
self.auth_port)
self.auth_uri = conf.get('auth_uri', default_auth_uri)
# Credentials used to verify this component with the Auth service since
# validating tokens is a privileged call
self.admin_token = conf.get('admin_token')
self.admin_user = conf.get('admin_user')
self.admin_password = conf.get('admin_password')
self.admin_tenant_name = conf.get('admin_tenant_name', 'admin')
# Token caching via memcache
self._cache = None
self._iso8601 = None
memcache_servers = conf.get('memcache_servers')
# By default the token will be cached for 5 minutes
self.token_cache_time = conf.get('token_cache_time', 300)
if memcache_servers:
try:
import memcache
import iso8601
LOG.info('Using memcache for caching token')
self._cache = memcache.Client(memcache_servers.split(','))
self._iso8601 = iso8601
except NameError as e:
LOG.warn('disabled caching due to missing libraries %s', e)
def __call__(self, env, start_response):
"""Handle incoming request.
Authenticate send downstream on success. Reject request if
we can't authenticate.
"""
LOG.debug('Authenticating user token')
try:
self._remove_auth_headers(env)
user_token = self._get_user_token_from_header(env)
token_info = self._validate_user_token(user_token)
user_headers = self._build_user_headers(token_info)
self._add_headers(env, user_headers)
return self.app(env, start_response)
except InvalidUserToken:
if self.delay_auth_decision:
LOG.info('Invalid user token - deferring reject downstream')
self._add_headers(env, {'X-Identity-Status': 'Invalid'})
return self.app(env, start_response)
else:
LOG.info('Invalid user token - rejecting request')
return self._reject_request(env, start_response)
except ServiceError, e:
LOG.critical('Unable to obtain admin token: %s' % e)
resp = webob.exc.HTTPServiceUnavailable()
return resp(env, start_response)
def _remove_auth_headers(self, env):
"""Remove headers so a user can't fake authentication.
:param env: wsgi request environment
"""
auth_headers = (
'X-Identity-Status',
'X-Tenant-Id',
'X-Tenant-Name',
'X-User-Id',
'X-User-Name',
'X-Roles',
# Deprecated
'X-User',
'X-Tenant',
'X-Role',
)
LOG.debug('Removing headers from request environment: %s' %
','.join(auth_headers))
self._remove_headers(env, auth_headers)
def _get_user_token_from_header(self, env):
"""Get token id from request.
:param env: wsgi request environment
:return token id
:raises InvalidUserToken if no token is provided in request
"""
token = self._get_header(env, 'X-Auth-Token',
self._get_header(env, 'X-Storage-Token'))
if token:
return token
else:
LOG.warn("Unable to find authentication token in headers: %s", env)
raise InvalidUserToken('Unable to find token in headers')
def _reject_request(self, env, start_response):
"""Redirect client to auth server.
:param env: wsgi request environment
:param start_response: wsgi response callback
:returns HTTPUnauthorized http response
"""
headers = [('WWW-Authenticate', 'Keystone uri=\'%s\'' % self.auth_uri)]
resp = webob.exc.HTTPUnauthorized('Authentication required', headers)
return resp(env, start_response)
def get_admin_token(self):
"""Return admin token, possibly fetching a new one.
:return admin token id
:raise ServiceError when unable to retrieve token from keystone
"""
if not self.admin_token:
self.admin_token = self._request_admin_token()
return self.admin_token
def _get_http_connection(self):
return self.http_client_class(self.auth_host, self.auth_port)
def _json_request(self, method, path, body=None, additional_headers=None):
"""HTTP request helper used to make json requests.
:param method: http method
:param path: relative request url
:param body: dict to encode to json as request body. Optional.
:param additional_headers: dict of additional headers to send with
http request. Optional.
:return (http response object, response body parsed as json)
:raise ServerError when unable to communicate with keystone
"""
conn = self._get_http_connection()
kwargs = {
'headers': {
'Content-type': 'application/json',
'Accept': 'application/json',
},
}
if additional_headers:
kwargs['headers'].update(additional_headers)
if body:
kwargs['body'] = json.dumps(body)
try:
conn.request(method, path, **kwargs)
response = conn.getresponse()
body = response.read()
except Exception, e:
LOG.error('HTTP connection exception: %s' % e)
raise ServiceError('Unable to communicate with keystone')
finally:
conn.close()
try:
data = json.loads(body)
except ValueError:
LOG.debug('Keystone did not return json-encoded body')
data = {}
return response, data
def _request_admin_token(self):
"""Retrieve new token as admin user from keystone.
:return token id upon success
:raises ServerError when unable to communicate with keystone
"""
params = {
'auth': {
'passwordCredentials': {
'username': self.admin_user,
'password': self.admin_password,
},
'tenantName': self.admin_tenant_name,
}
}
response, data = self._json_request('POST',
'/v2.0/tokens',
body=params)
try:
token = data['access']['token']['id']
assert token
return token
except (AssertionError, KeyError):
LOG.warn("Unexpected response from keystone service: %s", data)
raise ServiceError('invalid json response')
def _validate_user_token(self, user_token, retry=True):
"""Authenticate user token with keystone.
:param user_token: user's token id
:param retry: flag that forces the middleware to retry
user authentication when an indeterminate
response is received. Optional.
:return token object received from keystone on success
:raise InvalidUserToken if token is rejected
:raise ServiceError if unable to authenticate token
"""
cached = self._cache_get(user_token)
if cached:
return cached
headers = {'X-Auth-Token': self.get_admin_token()}
response, data = self._json_request('GET',
'/v2.0/tokens/%s' % user_token,
additional_headers=headers)
if response.status == 200:
self._cache_put(user_token, data)
return data
if response.status == 404:
# FIXME(ja): I'm assuming the 404 status means that user_token is
# invalid - not that the admin_token is invalid
self._cache_store_invalid(user_token)
LOG.warn("Authorization failed for token %s", user_token)
raise InvalidUserToken('Token authorization failed')
if response.status == 401:
LOG.info('Keystone rejected admin token %s, resetting', headers)
self.admin_token = None
else:
LOG.error('Bad response code while validating token: %s' %
response.status)
if retry:
LOG.info('Retrying validation')
return self._validate_user_token(user_token, False)
else:
LOG.warn("Invalid user token: %s. Keystone response: %s.",
user_token, data)
raise InvalidUserToken()
def _build_user_headers(self, token_info):
"""Convert token object into headers.
Build headers that represent authenticated user:
* X_IDENTITY_STATUS: Confirmed or Invalid
* X_TENANT_ID: id of tenant if tenant is present
* X_TENANT_NAME: name of tenant if tenant is present
* X_USER_ID: id of user
* X_USER_NAME: name of user
* X_ROLES: list of roles
Additional (deprecated) headers include:
* X_USER: name of user
* X_TENANT: For legacy compatibility before we had ID and Name
* X_ROLE: list of roles
:param token_info: token object returned by keystone on authentication
:raise InvalidUserToken when unable to parse token object
"""
user = token_info['access']['user']
token = token_info['access']['token']
roles = ','.join([role['name'] for role in user.get('roles', [])])
def get_tenant_info():
"""Returns a (tenant_id, tenant_name) tuple from context."""
def essex():
"""Essex puts the tenant ID and name on the token."""
return (token['tenant']['id'], token['tenant']['name'])
def pre_diablo():
"""Pre-diablo, Keystone only provided tenantId."""
return (token['tenantId'], token['tenantId'])
def default_tenant():
"""Assume the user's default tenant."""
return (user['tenantId'], user['tenantName'])
for method in [essex, pre_diablo, default_tenant]:
try:
return method()
except KeyError:
pass
raise InvalidUserToken('Unable to determine tenancy.')
tenant_id, tenant_name = get_tenant_info()
user_id = user['id']
user_name = user['name']
return {
'X-Identity-Status': 'Confirmed',
'X-Tenant-Id': tenant_id,
'X-Tenant-Name': tenant_name,
'X-User-Id': user_id,
'X-User-Name': user_name,
'X-Roles': roles,
# Deprecated
'X-User': user_name,
'X-Tenant': tenant_name,
'X-Role': roles,
'X-Admin-User': self.admin_user,
'X-Admin-Pass': self.admin_password,
'X-Auth-Url': self.conf['auth_uri'],
}
def _header_to_env_var(self, key):
"""Convert header to wsgi env variable.
:param key: http header name (ex. 'X-Auth-Token')
:return wsgi env variable name (ex. 'HTTP_X_AUTH_TOKEN')
"""
return 'HTTP_%s' % (key.replace('-', '_').upper())
def _add_headers(self, env, headers):
"""Add http headers to environment."""
for (k, v) in headers.iteritems():
env_key = self._header_to_env_var(k)
env[env_key] = v
def _remove_headers(self, env, keys):
"""Remove http headers from environment."""
for k in keys:
env_key = self._header_to_env_var(k)
try:
del env[env_key]
except KeyError:
pass
def _get_header(self, env, key, default=None):
"""Get http header from environment."""
env_key = self._header_to_env_var(key)
return env.get(env_key, default)
def _cache_get(self, token):
"""Return token information from cache.
If token is invalid raise InvalidUserToken
return token only if fresh (not expired).
"""
if self._cache and token:
key = 'tokens/%s' % token
cached = self._cache.get(key)
if cached == 'invalid':
LOG.debug('Cached Token %s is marked unauthorized', token)
raise InvalidUserToken('Token authorization failed')
if cached:
data, expires = cached
if time.time() < float(expires):
LOG.debug('Returning cached token %s', token)
return data
else:
LOG.debug('Cached Token %s seems expired', token)
def _cache_put(self, token, data):
"""Put token data into the cache.
Stores the parsed expire date in cache allowing
quick check of token freshness on retrieval.
"""
if self._cache and data:
key = 'tokens/%s' % token
if 'token' in data.get('access', {}):
timestamp = data['access']['token']['expires']
expires = self._iso8601.parse_date(timestamp).strftime('%s')
else:
LOG.error('invalid token format')
return
LOG.debug('Storing %s token in memcache', token)
self._cache.set(key,
(data, expires),
time=self.token_cache_time)
def _cache_store_invalid(self, token):
"""Store invalid token in cache."""
if self._cache:
key = 'tokens/%s' % token
LOG.debug('Marking token %s as unauthorized in memcache', token)
self._cache.set(key,
'invalid',
time=self.token_cache_time)
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 AuthProtocol(app, conf)
return auth_filter
def app_factory(global_conf, **local_conf):
conf = global_conf.copy()
conf.update(local_conf)
return AuthProtocol(None, conf)
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