Merge remote-tracking branch 'middleware/master'

keystonemiddleware/memcache_crypt.py

@@ -0,0 +1,208 @@
+# Copyright 2010-2013 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.
+
+"""
+Utilities for memcache encryption and integrity check.
+
+Data should be serialized before entering these functions. Encryption
+has a dependency on the pycrypto. If pycrypto is not available,
+CryptoUnavailableError will be raised.
+
+This module will not be called unless signing or encryption is enabled
+in the config. It will always validate signatures, and will decrypt
+data if encryption is enabled. It is not valid to mix protection
+modes.
+
+"""
+
+import base64
+import functools
+import hashlib
+import hmac
+import math
+import os
+import six
+import sys
+
+# make sure pycrypto is available
+try:
+    from Crypto.Cipher import AES
+except ImportError:
+    AES = None
+
+HASH_FUNCTION = hashlib.sha384
+DIGEST_LENGTH = HASH_FUNCTION().digest_size
+DIGEST_SPLIT = DIGEST_LENGTH // 3
+DIGEST_LENGTH_B64 = 4 * int(math.ceil(DIGEST_LENGTH / 3.0))
+
+
+class InvalidMacError(Exception):
+    """raise when unable to verify MACed data.
+
+    This usually indicates that data had been expectedly modified in memcache.
+
+    """
+    pass
+
+
+class DecryptError(Exception):
+    """raise when unable to decrypt encrypted data.
+
+    """
+    pass
+
+
+class CryptoUnavailableError(Exception):
+    """raise when Python Crypto module is not available.
+
+    """
+    pass
+
+
+def assert_crypto_availability(f):
+    """Ensure Crypto module is available."""
+
+    @functools.wraps(f)
+    def wrapper(*args, **kwds):
+        if AES is None:
+            raise CryptoUnavailableError()
+        return f(*args, **kwds)
+    return wrapper
+
+
+if sys.version_info >= (3, 3):
+    constant_time_compare = hmac.compare_digest
+else:
+    def constant_time_compare(first, second):
+        """Returns True if both string inputs are equal, otherwise False.
+
+        This function should take a constant amount of time regardless of
+        how many characters in the strings match.
+
+        """
+        if len(first) != len(second):
+            return False
+        result = 0
+        if six.PY3 and isinstance(first, bytes) and isinstance(second, bytes):
+            for x, y in zip(first, second):
+                result |= x ^ y
+        else:
+            for x, y in zip(first, second):
+                result |= ord(x) ^ ord(y)
+        return result == 0
+
+
+def derive_keys(token, secret, strategy):
+    """Derives keys for MAC and ENCRYPTION from the user-provided
+    secret. The resulting keys should be passed to the protect and
+    unprotect functions.
+
+    As suggested by NIST Special Publication 800-108, this uses the
+    first 128 bits from the sha384 KDF for the obscured cache key
+    value, the second 128 bits for the message authentication key and
+    the remaining 128 bits for the encryption key.
+
+    This approach is faster than computing a separate hmac as the KDF
+    for each desired key.
+    """
+    digest = hmac.new(secret, token + strategy, HASH_FUNCTION).digest()
+    return {'CACHE_KEY': digest[:DIGEST_SPLIT],
+            'MAC': digest[DIGEST_SPLIT: 2 * DIGEST_SPLIT],
+            'ENCRYPTION': digest[2 * DIGEST_SPLIT:],
+            'strategy': strategy}
+
+
+def sign_data(key, data):
+    """Sign the data using the defined function and the derived key."""
+    mac = hmac.new(key, data, HASH_FUNCTION).digest()
+    return base64.b64encode(mac)
+
+
+@assert_crypto_availability
+def encrypt_data(key, data):
+    """Encrypt the data with the given secret key.
+
+    Padding is n bytes of the value n, where 1 <= n <= blocksize.
+    """
+    iv = os.urandom(16)
+    cipher = AES.new(key, AES.MODE_CBC, iv)
+    padding = 16 - len(data) % 16
+    return iv + cipher.encrypt(data + six.int2byte(padding) * padding)
+
+
+@assert_crypto_availability
+def decrypt_data(key, data):
+    """Decrypt the data with the given secret key."""
+    iv = data[:16]
+    cipher = AES.new(key, AES.MODE_CBC, iv)
+    try:
+        result = cipher.decrypt(data[16:])
+    except Exception:
+        raise DecryptError('Encrypted data appears to be corrupted.')
+
+    # Strip the last n padding bytes where n is the last value in
+    # the plaintext
+    return result[:-1 * six.byte2int([result[-1]])]
+
+
+def protect_data(keys, data):
+    """Given keys and serialized data, returns an appropriately
+    protected string suitable for storage in the cache.
+
+    """
+    if keys['strategy'] == b'ENCRYPT':
+        data = encrypt_data(keys['ENCRYPTION'], data)
+
+    encoded_data = base64.b64encode(data)
+
+    signature = sign_data(keys['MAC'], encoded_data)
+    return signature + encoded_data
+
+
+def unprotect_data(keys, signed_data):
+    """Given keys and cached string data, verifies the signature,
+    decrypts if necessary, and returns the original serialized data.
+
+    """
+    # cache backends return None when no data is found. We don't mind
+    # that this particular special value is unsigned.
+    if signed_data is None:
+        return None
+
+    # First we calculate the signature
+    provided_mac = signed_data[:DIGEST_LENGTH_B64]
+    calculated_mac = sign_data(
+        keys['MAC'],
+        signed_data[DIGEST_LENGTH_B64:])
+
+    # Then verify that it matches the provided value
+    if not constant_time_compare(provided_mac, calculated_mac):
+        raise InvalidMacError('Invalid MAC; data appears to be corrupted.')
+
+    data = base64.b64decode(signed_data[DIGEST_LENGTH_B64:])
+
+    # then if necessary decrypt the data
+    if keys['strategy'] == b'ENCRYPT':
+        data = decrypt_data(keys['ENCRYPTION'], data)
+
+    return data
+
+
+def get_cache_key(keys):
+    """Given keys generated by derive_keys(), returns a base64
+    encoded value suitable for use as a cache key in memcached.
+
+    """
+    return base64.b64encode(keys['CACHE_KEY'])

keystonemiddleware/s3_token.py

@@ -0,0 +1,264 @@
+# 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:
+
+* Get a request from the swift3 middleware with an S3 Authorization
+  access key.
+* Validate s3 token in Keystone.
+* Transform the account name to AUTH_%(tenant_name).
+
+"""
+
+import logging
+import webob
+
+import requests
+import six
+from six.moves import urllib
+
+from keystoneclient.openstack.common import jsonutils
+
+
+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: %d > %d' % (minsegs, 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):
+    """Auth Middleware that handles S3 authenticating client calls."""
+
+    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 = 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('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']
+        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