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# Copyright (c) 2013 Red Hat, Inc.
#
# 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 time import time
from traceback import format_exc
from eventlet import Timeout
from swift.common.swob import Request
from swift.common.swob import HTTPBadRequest, HTTPForbidden, HTTPNotFound, \
HTTPSeeOther
from swift.common.middleware.acl import clean_acl, parse_acl, referrer_allowed
from swift.common.utils import cache_from_env, get_logger, \
split_path, config_true_value
class KerbAuth(object):
"""
Test authentication and authorization system.
Add to your pipeline in proxy-server.conf, such as::
[pipeline:main]
pipeline = catch_errors cache kerbauth proxy-server
Set account auto creation to true in proxy-server.conf::
[app:proxy-server]
account_autocreate = true
And add a kerbauth filter section, such as::
[filter:kerbauth]
use = egg:swift#kerbauth
See the proxy-server.conf-sample for more information.
: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 = get_logger(conf, log_route='kerbauth')
self.log_headers = config_true_value(conf.get('log_headers', 'f'))
self.reseller_prefix = conf.get('reseller_prefix', 'AUTH').strip()
if self.reseller_prefix and self.reseller_prefix[-1] != '_':
self.reseller_prefix += '_'
self.logger.set_statsd_prefix('kerbauth.%s' % (
self.reseller_prefix if self.reseller_prefix else 'NONE',))
self.auth_prefix = conf.get('auth_prefix', '/auth/')
if not self.auth_prefix or not self.auth_prefix.strip('/'):
self.logger.warning('Rewriting invalid auth prefix "%s" to '
'"/auth/" (Non-empty auth prefix path '
'is required)' % self.auth_prefix)
self.auth_prefix = '/auth/'
if self.auth_prefix[0] != '/':
self.auth_prefix = '/' + self.auth_prefix
if self.auth_prefix[-1] != '/':
self.auth_prefix += '/'
self.token_life = int(conf.get('token_life', 86400))
self.allow_overrides = config_true_value(
conf.get('allow_overrides', 't'))
self.storage_url_scheme = conf.get('storage_url_scheme', 'default')
self.ext_authentication_url = conf.get('ext_authentication_url')
if not self.ext_authentication_url:
raise RuntimeError("Missing filter parameter ext_authentication_"
"url in /etc/swift/proxy-server.conf")
def __call__(self, env, start_response):
"""
Accepts a standard WSGI application call, authenticating the request
and installing callback hooks for authorization and ACL header
validation. For an authenticated request, REMOTE_USER will be set to a
comma separated list of the user's groups.
If the request matches the self.auth_prefix, the request will be
routed through the internal auth request handler (self.handle).
This is to handle granting tokens, etc.
"""
if self.allow_overrides and env.get('swift.authorize_override', False):
return self.app(env, start_response)
if env.get('PATH_INFO', '').startswith(self.auth_prefix):
return self.handle(env, start_response)
token = env.get('HTTP_X_AUTH_TOKEN', env.get('HTTP_X_STORAGE_TOKEN'))
if token and token.startswith(self.reseller_prefix):
groups = self.get_groups(env, token)
if groups:
user = groups and groups.split(',', 1)[0] or ''
trans_id = env.get('swift.trans_id')
self.logger.debug('User: %s uses token %s (trans_id %s)' %
(user, token, trans_id))
env['REMOTE_USER'] = groups
env['swift.authorize'] = self.authorize
env['swift.clean_acl'] = clean_acl
if '.reseller_admin' in groups:
env['reseller_request'] = True
else:
# Invalid token (may be expired)
return HTTPSeeOther(
location=self.ext_authentication_url)(env, start_response)
else:
# With a non-empty reseller_prefix, I would like to be called
# back for anonymous access to accounts I know I'm the
# definitive auth for.
try:
version, rest = split_path(env.get('PATH_INFO', ''),
1, 2, True)
except ValueError:
version, rest = None, None
self.logger.increment('errors')
# Not my token, not my account, I can't authorize this request,
# deny all is a good idea if not already set...
if 'swift.authorize' not in env:
env['swift.authorize'] = self.denied_response
return self.app(env, start_response)
def get_groups(self, env, token):
"""
Get groups for the given token.
:param env: The current WSGI environment dictionary.
:param token: Token to validate and return a group string for.
:returns: None if the token is invalid or a string containing a comma
separated list of groups the authenticated user is a member
of. The first group in the list is also considered a unique
identifier for that user.
"""
groups = None
memcache_client = cache_from_env(env)
if not memcache_client:
raise Exception('Memcache required')
memcache_token_key = '%s/token/%s' % (self.reseller_prefix, token)
cached_auth_data = memcache_client.get(memcache_token_key)
if cached_auth_data:
expires, groups = cached_auth_data
if expires < time():
groups = None
return groups
def authorize(self, req):
"""
Returns None if the request is authorized to continue or a standard
WSGI response callable if not.
Assumes that user groups are all lower case, which is true when Red Hat
Enterprise Linux Identity Management is used.
"""
try:
version, account, container, obj = req.split_path(1, 4, True)
except ValueError:
self.logger.increment('errors')
return HTTPNotFound(request=req)
if not account or not account.startswith(self.reseller_prefix):
self.logger.debug("Account name: %s doesn't start with "
"reseller_prefix: %s."
% (account, self.reseller_prefix))
return self.denied_response(req)
user_groups = (req.remote_user or '').split(',')
account_user = user_groups[1] if len(user_groups) > 1 else None
# If the user is in the reseller_admin group for our prefix, he gets
# full access to all accounts we manage. For the default reseller
# prefix, the group name is auth_reseller_admin.
admin_group = ("%sreseller_admin" % self.reseller_prefix).lower()
if admin_group in user_groups and \
account != self.reseller_prefix and \
account[len(self.reseller_prefix)] != '.':
req.environ['swift_owner'] = True
return None
# The "account" is part of the request URL, and already contains the
# reseller prefix, like in "/v1/AUTH_vol1/pictures/pic1.png".
if account.lower() in user_groups and \
(req.method not in ('DELETE', 'PUT') or container):
# If the user is admin for the account and is not trying to do an
# account DELETE or PUT...
req.environ['swift_owner'] = True
self.logger.debug("User %s has admin authorizing."
% account_user)
return None
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):
self.logger.debug("Allow request with container sync-key: %s."
% req.environ['swift_sync_key'])
return None
if req.method == 'OPTIONS':
#allow OPTIONS requests to proceed as normal
self.logger.debug("Allow OPTIONS request.")
return None
referrers, groups = parse_acl(getattr(req, 'acl', None))
if referrer_allowed(req.referer, referrers):
if obj or '.rlistings' in groups:
self.logger.debug("Allow authorizing %s via referer ACL."
% req.referer)
return None
for user_group in user_groups:
if user_group in groups:
self.logger.debug("User %s allowed in ACL: %s authorizing."
% (account_user, user_group))
return None
return self.denied_response(req)
def denied_response(self, req):
"""
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:
self.logger.increment('forbidden')
return HTTPForbidden(request=req)
else:
return HTTPSeeOther(location=self.ext_authentication_url)
def handle(self, env, start_response):
"""
WSGI entry point for auth requests (ones that match the
self.auth_prefix).
Wraps env in swob.Request object and passes it down.
:param env: WSGI environment dictionary
:param start_response: WSGI callable
"""
try:
req = Request(env)
if self.auth_prefix:
req.path_info_pop()
req.bytes_transferred = '-'
req.client_disconnect = False
if 'x-storage-token' in req.headers and \
'x-auth-token' not in req.headers:
req.headers['x-auth-token'] = req.headers['x-storage-token']
return self.handle_request(req)(env, start_response)
except (Exception, Timeout):
print "EXCEPTION IN handle: %s: %s" % (format_exc(), env)
self.logger.increment('errors')
start_response('500 Server Error',
[('Content-Type', 'text/plain')])
return ['Internal server error.\n']
def handle_request(self, req):
"""
Entry point for auth requests (ones that match the self.auth_prefix).
Should return a WSGI-style callable (such as webob.Response).
:param req: swob.Request object
"""
req.start_time = time()
handler = None
try:
version, account, user, _junk = req.split_path(1, 4, True)
except ValueError:
self.logger.increment('errors')
return HTTPNotFound(request=req)
if version in ('v1', 'v1.0', 'auth'):
if req.method == 'GET':
handler = self.handle_get_token
if not handler:
self.logger.increment('errors')
req.response = HTTPBadRequest(request=req)
else:
req.response = handler(req)
return req.response
def handle_get_token(self, req):
"""
Handles the various `request for token and service end point(s)` calls.
There are various formats to support the various auth servers in the
past. Examples::
GET <auth-prefix>/v1/<act>/auth
GET <auth-prefix>/auth
GET <auth-prefix>/v1.0
All formats require GSS (Kerberos) authentication.
On successful authentication, the response will have X-Auth-Token
set to the token to use with Swift.
:param req: The swob.Request to process.
:returns: swob.Response, 2xx on success with data set as explained
above.
"""
# Validate the request info
try:
pathsegs = split_path(req.path_info, 1, 3, True)
except ValueError:
self.logger.increment('errors')
return HTTPNotFound(request=req)
if not ((pathsegs[0] == 'v1' and pathsegs[2] == 'auth')
or pathsegs[0] in ('auth', 'v1.0')):
return HTTPBadRequest(request=req)
return HTTPSeeOther(location=self.ext_authentication_url)
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 KerbAuth(app, conf)
return auth_filter
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