1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
|
# 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.
import contextlib
import hashlib
from oslo_serialization import jsonutils
import six
from keystonemiddleware.auth_token import _exceptions as exc
from keystonemiddleware.auth_token import _memcache_crypt as memcache_crypt
from keystonemiddleware.i18n import _, _LE
from keystonemiddleware.openstack.common import memorycache
def _hash_key(key):
"""Turn a set of arguments into a SHA256 hash.
Using a known-length cache key is important to ensure that memcache
maximum key length is not exceeded causing failures to validate.
"""
if isinstance(key, six.text_type):
# NOTE(morganfainberg): Ensure we are always working with a bytes
# type required for the hasher. In python 2.7 it is possible to
# get a text_type (unicode). In python 3.4 all strings are
# text_type and not bytes by default. This encode coerces the
# text_type to the appropriate bytes values.
key = key.encode('utf-8')
return hashlib.sha256(key).hexdigest()
class _CachePool(list):
"""A lazy pool of cache references."""
def __init__(self, cache, memcached_servers):
self._environment_cache = cache
self._memcached_servers = memcached_servers
@contextlib.contextmanager
def reserve(self):
"""Context manager to manage a pooled cache reference."""
if self._environment_cache is not None:
# skip pooling and just use the cache from the upstream filter
yield self._environment_cache
return # otherwise the context manager will continue!
try:
c = self.pop()
except IndexError:
# the pool is empty, so we need to create a new client
c = memorycache.get_client(self._memcached_servers)
try:
yield c
finally:
self.append(c)
class _MemcacheClientPool(object):
"""An advanced memcached client pool that is eventlet safe."""
def __init__(self, memcache_servers, memcache_dead_retry=None,
memcache_pool_maxsize=None, memcache_pool_unused_timeout=None,
memcache_pool_conn_get_timeout=None,
memcache_pool_socket_timeout=None):
# NOTE(morganfainberg): import here to avoid hard dependency on
# python-memcached library.
global _memcache_pool
from keystonemiddleware.auth_token import _memcache_pool
self._pool = _memcache_pool.MemcacheClientPool(
memcache_servers,
arguments={
'dead_retry': memcache_dead_retry,
'socket_timeout': memcache_pool_socket_timeout,
},
maxsize=memcache_pool_maxsize,
unused_timeout=memcache_pool_unused_timeout,
conn_get_timeout=memcache_pool_conn_get_timeout,
)
@contextlib.contextmanager
def reserve(self):
with self._pool.get() as client:
yield client
class TokenCache(object):
"""Encapsulates the auth_token token cache functionality.
auth_token caches tokens that it's seen so that when a token is re-used the
middleware doesn't have to do a more expensive operation (like going to the
identity server) to validate the token.
initialize() must be called before calling the other methods.
Store a valid token in the cache using store(); mark a token as invalid in
the cache using store_invalid().
Check if a token is in the cache and retrieve it using get().
"""
_CACHE_KEY_TEMPLATE = 'tokens/%s'
_INVALID_INDICATOR = 'invalid'
def __init__(self, log, cache_time=None,
env_cache_name=None, memcached_servers=None,
use_advanced_pool=False, memcache_pool_dead_retry=None,
memcache_pool_maxsize=None, memcache_pool_unused_timeout=None,
memcache_pool_conn_get_timeout=None,
memcache_pool_socket_timeout=None):
self._LOG = log
self._cache_time = cache_time
self._env_cache_name = env_cache_name
self._memcached_servers = memcached_servers
self._use_advanced_pool = use_advanced_pool
self._memcache_pool_dead_retry = memcache_pool_dead_retry,
self._memcache_pool_maxsize = memcache_pool_maxsize,
self._memcache_pool_unused_timeout = memcache_pool_unused_timeout
self._memcache_pool_conn_get_timeout = memcache_pool_conn_get_timeout
self._memcache_pool_socket_timeout = memcache_pool_socket_timeout
self._cache_pool = None
self._initialized = False
def _get_cache_pool(self, cache, memcache_servers, use_advanced_pool=False,
memcache_dead_retry=None, memcache_pool_maxsize=None,
memcache_pool_unused_timeout=None,
memcache_pool_conn_get_timeout=None,
memcache_pool_socket_timeout=None):
if use_advanced_pool is True and memcache_servers and cache is None:
return _MemcacheClientPool(
memcache_servers,
memcache_dead_retry=memcache_dead_retry,
memcache_pool_maxsize=memcache_pool_maxsize,
memcache_pool_unused_timeout=memcache_pool_unused_timeout,
memcache_pool_conn_get_timeout=memcache_pool_conn_get_timeout,
memcache_pool_socket_timeout=memcache_pool_socket_timeout)
else:
return _CachePool(cache, memcache_servers)
def initialize(self, env):
if self._initialized:
return
self._cache_pool = self._get_cache_pool(
env.get(self._env_cache_name),
self._memcached_servers,
use_advanced_pool=self._use_advanced_pool,
memcache_dead_retry=self._memcache_pool_dead_retry,
memcache_pool_maxsize=self._memcache_pool_maxsize,
memcache_pool_unused_timeout=self._memcache_pool_unused_timeout,
memcache_pool_conn_get_timeout=self._memcache_pool_conn_get_timeout
)
self._initialized = True
def store(self, token_id, data):
"""Put token data into the cache.
"""
self._LOG.debug('Storing token in cache')
self._cache_store(token_id, data)
def store_invalid(self, token_id):
"""Store invalid token in cache."""
self._LOG.debug('Marking token as unauthorized in cache')
self._cache_store(token_id, self._INVALID_INDICATOR)
def _get_cache_key(self, token_id):
"""Get a unique key for this token id.
Turn the token_id into something that can uniquely identify that token
in a key value store.
As this is generally the first function called in a key lookup this
function also returns a context object. This context object is not
modified or used by the Cache object but is passed back on subsequent
functions so that decryption or other data can be shared throughout a
cache lookup.
:param str token_id: The unique token id.
:returns: A tuple of a string key and an implementation specific
context object
"""
# NOTE(jamielennox): in the basic implementation there is no need for
# a context so just pass None as it will only get passed back later.
unused_context = None
return self._CACHE_KEY_TEMPLATE % _hash_key(token_id), unused_context
def _deserialize(self, data, context):
"""Deserialize data from the cache back into python objects.
Take data retrieved from the cache and return an appropriate python
dictionary.
:param str data: The data retrieved from the cache.
:param object context: The context that was returned from
_get_cache_key.
:returns: The python object that was saved.
"""
# memory cache will handle deserialization for us
return data
def _serialize(self, data, context):
"""Serialize data so that it can be saved to the cache.
Take python objects and serialize them so that they can be saved into
the cache.
:param object data: The data to be cached.
:param object context: The context that was returned from
_get_cache_key.
:returns: The python object that was saved.
"""
# memory cache will handle serialization for us
return data
def get(self, token_id):
"""Return token information from cache.
If token is invalid raise exc.InvalidToken
return token only if fresh (not expired).
"""
if not token_id:
# Nothing to do
return
key, context = self._get_cache_key(token_id)
with self._cache_pool.reserve() as cache:
serialized = cache.get(key)
if serialized is None:
return None
if isinstance(serialized, six.text_type):
serialized = serialized.encode('utf8')
data = self._deserialize(serialized, context)
# Note that _INVALID_INDICATOR and (data, expires) are the only
# valid types of serialized cache entries, so there is not
# a collision with jsonutils.loads(serialized) == None.
if not isinstance(data, six.string_types):
data = data.decode('utf-8')
cached = jsonutils.loads(data)
if cached == self._INVALID_INDICATOR:
self._LOG.debug('Cached Token is marked unauthorized')
raise exc.InvalidToken(_('Token authorization failed'))
# NOTE(jamielennox): Cached values used to be stored as a tuple of data
# and expiry time. They no longer are but we have to allow some time to
# transition the old format so if it's a tuple just return the data.
try:
data, expires = cached
except ValueError:
data = cached
return data
def _cache_store(self, token_id, data):
"""Store value into memcache.
data may be _INVALID_INDICATOR or a tuple like (data, expires)
"""
data = jsonutils.dumps(data)
if isinstance(data, six.text_type):
data = data.encode('utf-8')
cache_key, context = self._get_cache_key(token_id)
data_to_store = self._serialize(data, context)
with self._cache_pool.reserve() as cache:
cache.set(cache_key, data_to_store, time=self._cache_time)
class SecureTokenCache(TokenCache):
"""A token cache that stores tokens encrypted.
A more secure version of TokenCache that will encrypt tokens before
caching them.
"""
def __init__(self, log, security_strategy, secret_key, **kwargs):
super(SecureTokenCache, self).__init__(log, **kwargs)
security_strategy = security_strategy.upper()
if security_strategy not in ('MAC', 'ENCRYPT'):
msg = _('memcache_security_strategy must be ENCRYPT or MAC')
raise exc.ConfigurationError(msg)
if not secret_key:
msg = _('memcache_secret_key must be defined when a '
'memcache_security_strategy is defined')
raise exc.ConfigurationError(msg)
if isinstance(security_strategy, six.string_types):
security_strategy = security_strategy.encode('utf-8')
if isinstance(secret_key, six.string_types):
secret_key = secret_key.encode('utf-8')
self._security_strategy = security_strategy
self._secret_key = secret_key
def _get_cache_key(self, token_id):
context = memcache_crypt.derive_keys(token_id,
self._secret_key,
self._security_strategy)
key = self._CACHE_KEY_TEMPLATE % memcache_crypt.get_cache_key(context)
return key, context
def _deserialize(self, data, context):
try:
# unprotect_data will return None if raw_cached is None
return memcache_crypt.unprotect_data(context, data)
except Exception:
msg = _LE('Failed to decrypt/verify cache data')
self._LOG.exception(msg)
# this should have the same effect as data not
# found in cache
return None
def _serialize(self, data, context):
return memcache_crypt.protect_data(context, data)
|