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# Copyright 2012 OpenStack Foundation
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011,2012 Akira YOSHIYAMA <akirayoshiyama@gmail.com>
# All Rights Reserved.
#
# 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.
# This source code is based ./auth_token.py and ./ec2_token.py.
# See them for their copyright.
"""
S3 Token Middleware
This WSGI component:
* Gets a request from the swift3 middleware with an S3 Authorization
access key.
* Validates s3 token in Keystone.
* Transforms the account name to AUTH_%(tenant_name).
"""
import logging
import webob
from oslo_serialization import jsonutils
from oslo_utils import strutils
import requests
import six
from six.moves import urllib
from keystonemiddleware.i18n import _, _LI
PROTOCOL_NAME = 'S3 Token Authentication'
# TODO(kun): remove it after oslo merge this.
def _split_path(path, minsegs=1, maxsegs=None, rest_with_last=False):
"""Validate and split the given HTTP request path.
**Examples**::
['a'] = _split_path('/a')
['a', None] = _split_path('/a', 1, 2)
['a', 'c'] = _split_path('/a/c', 1, 2)
['a', 'c', 'o/r'] = _split_path('/a/c/o/r', 1, 3, True)
:param path: HTTP Request path to be split
:param minsegs: Minimum number of segments to be extracted
:param maxsegs: Maximum number of segments to be extracted
:param rest_with_last: If True, trailing data will be returned as part
of last segment. If False, and there is
trailing data, raises ValueError.
:returns: list of segments with a length of maxsegs (non-existent
segments will return as None)
:raises: ValueError if given an invalid path
"""
if not maxsegs:
maxsegs = minsegs
if minsegs > maxsegs:
raise ValueError(_('minsegs > maxsegs: %(min)d > %(max)d)') %
{'min': minsegs, 'max': maxsegs})
if rest_with_last:
segs = path.split('/', maxsegs)
minsegs += 1
maxsegs += 1
count = len(segs)
if (segs[0] or count < minsegs or count > maxsegs or
'' in segs[1:minsegs]):
raise ValueError(_('Invalid path: %s') % urllib.parse.quote(path))
else:
minsegs += 1
maxsegs += 1
segs = path.split('/', maxsegs)
count = len(segs)
if (segs[0] or count < minsegs or count > maxsegs + 1 or
'' in segs[1:minsegs] or
(count == maxsegs + 1 and segs[maxsegs])):
raise ValueError(_('Invalid path: %s') % urllib.parse.quote(path))
segs = segs[1:maxsegs]
segs.extend([None] * (maxsegs - 1 - len(segs)))
return segs
class ServiceError(Exception):
pass
class S3Token(object):
"""Middleware that handles S3 authentication."""
def __init__(self, app, conf):
"""Common initialization code."""
self._app = app
self._logger = logging.getLogger(conf.get('log_name', __name__))
self._logger.debug('Starting the %s component', PROTOCOL_NAME)
self._reseller_prefix = conf.get('reseller_prefix', 'AUTH_')
# where to find the auth service (we use this to validate tokens)
auth_host = conf.get('auth_host')
auth_port = int(conf.get('auth_port', 35357))
auth_protocol = conf.get('auth_protocol', 'https')
self._request_uri = '%s://%s:%s' % (auth_protocol, auth_host,
auth_port)
# SSL
insecure = strutils.bool_from_string(conf.get('insecure', False))
cert_file = conf.get('certfile')
key_file = conf.get('keyfile')
if insecure:
self._verify = False
elif cert_file and key_file:
self._verify = (cert_file, key_file)
elif cert_file:
self._verify = cert_file
else:
self._verify = None
def _deny_request(self, code):
error_table = {
'AccessDenied': (401, 'Access denied'),
'InvalidURI': (400, 'Could not parse the specified URI'),
}
resp = webob.Response(content_type='text/xml')
resp.status = error_table[code][0]
error_msg = ('<?xml version="1.0" encoding="UTF-8"?>\r\n'
'<Error>\r\n <Code>%s</Code>\r\n '
'<Message>%s</Message>\r\n</Error>\r\n' %
(code, error_table[code][1]))
if six.PY3:
error_msg = error_msg.encode()
resp.body = error_msg
return resp
def _json_request(self, creds_json):
headers = {'Content-Type': 'application/json'}
try:
response = requests.post('%s/v2.0/s3tokens' % self._request_uri,
headers=headers, data=creds_json,
verify=self._verify)
except requests.exceptions.RequestException as e:
self._logger.info(_LI('HTTP connection exception: %s'), e)
resp = self._deny_request('InvalidURI')
raise ServiceError(resp)
if response.status_code < 200 or response.status_code >= 300:
self._logger.debug('Keystone reply error: status=%s reason=%s',
response.status_code, response.reason)
resp = self._deny_request('AccessDenied')
raise ServiceError(resp)
return response
def __call__(self, environ, start_response):
"""Handle incoming request. authenticate and send downstream."""
req = webob.Request(environ)
self._logger.debug('Calling S3Token middleware.')
try:
parts = _split_path(req.path, 1, 4, True)
version, account, container, obj = parts
except ValueError:
msg = 'Not a path query, skipping.'
self._logger.debug(msg)
return self._app(environ, start_response)
# Read request signature and access id.
if 'Authorization' not in req.headers:
msg = 'No Authorization header. skipping.'
self._logger.debug(msg)
return self._app(environ, start_response)
token = req.headers.get('X-Auth-Token',
req.headers.get('X-Storage-Token'))
if not token:
msg = 'You did not specify an auth or a storage token. skipping.'
self._logger.debug(msg)
return self._app(environ, start_response)
auth_header = req.headers['Authorization']
try:
access, signature = auth_header.split(' ')[-1].rsplit(':', 1)
except ValueError:
msg = 'You have an invalid Authorization header: %s'
self._logger.debug(msg, auth_header)
return self._deny_request('InvalidURI')(environ, start_response)
# NOTE(chmou): This is to handle the special case with nova
# when we have the option s3_affix_tenant. We will force it to
# connect to another account than the one
# authenticated. Before people start getting worried about
# security, I should point that we are connecting with
# username/token specified by the user but instead of
# connecting to its own account we will force it to go to an
# another account. In a normal scenario if that user don't
# have the reseller right it will just fail but since the
# reseller account can connect to every account it is allowed
# by the swift_auth middleware.
force_tenant = None
if ':' in access:
access, force_tenant = access.split(':')
# Authenticate request.
creds = {'credentials': {'access': access,
'token': token,
'signature': signature}}
creds_json = jsonutils.dumps(creds)
self._logger.debug('Connecting to Keystone sending this JSON: %s',
creds_json)
# NOTE(vish): We could save a call to keystone by having
# keystone return token, tenant, user, and roles
# from this call.
#
# NOTE(chmou): We still have the same problem we would need to
# change token_auth to detect if we already
# identified and not doing a second query and just
# pass it through to swiftauth in this case.
try:
resp = self._json_request(creds_json)
except ServiceError as e:
resp = e.args[0]
msg = 'Received error, exiting middleware with error: %s'
self._logger.debug(msg, resp.status_code)
return resp(environ, start_response)
self._logger.debug('Keystone Reply: Status: %d, Output: %s',
resp.status_code, resp.content)
try:
identity_info = resp.json()
token_id = str(identity_info['access']['token']['id'])
tenant = identity_info['access']['token']['tenant']
except (ValueError, KeyError):
error = 'Error on keystone reply: %d %s'
self._logger.debug(error, resp.status_code, resp.content)
return self._deny_request('InvalidURI')(environ, start_response)
req.headers['X-Auth-Token'] = token_id
tenant_to_connect = force_tenant or tenant['id']
if six.PY2 and isinstance(tenant_to_connect, six.text_type):
tenant_to_connect = tenant_to_connect.encode('utf-8')
self._logger.debug('Connecting with tenant: %s', tenant_to_connect)
new_tenant_name = '%s%s' % (self._reseller_prefix, tenant_to_connect)
environ['PATH_INFO'] = environ['PATH_INFO'].replace(account,
new_tenant_name)
return self._app(environ, start_response)
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 S3Token(app, conf)
return auth_filter
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