File Content: session.py from ._compat import PY2, pickle, http_cookies, unicode_text, b64encode, b64decode, string_type import os import time from datetime import datetime, timedelta from beaker.crypto import hmac as HMAC, hmac_sha1 as SHA1, sha1, get_nonce_size, DEFAULT_NONCE_BITS, get_crypto_module from beaker import crypto, util from beaker.cache import clsmap from beaker.exceptions import BeakerException, InvalidCryptoBackendError from beaker.cookie import SimpleCookie months = (None, "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec") weekdays = ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun") __all__ = ['SignedCookie', 'Session', 'InvalidSignature'] class _InvalidSignatureType(object): """Returned from SignedCookie when the value's signature was invalid.""" def __nonzero__(self): return False def __bool__(self): return False InvalidSignature = _InvalidSignatureType() try: import uuid def _session_id(): return uuid.uuid4().hex except ImportError: import random if hasattr(os, 'getpid'): getpid = os.getpid else: def getpid(): return '' def _session_id(): id_str = "%f%s%f%s" % ( time.time(), id({}), random.random(), getpid() ) # NB: nothing against second parameter to b64encode, but it seems # to be slower than simple chained replacement if not PY2: raw_id = b64encode(sha1(id_str.encode('ascii')).digest()) return str(raw_id.replace(b'+', b'-').replace(b'/', b'_').rstrip(b'=')) else: raw_id = b64encode(sha1(id_str).digest()) return raw_id.replace('+', '-').replace('/', '_').rstrip('=') class SignedCookie(SimpleCookie): """Extends python cookie to give digital signature support""" def __init__(self, secret, input=None): self.secret = secret.encode('UTF-8') http_cookies.BaseCookie.__init__(self, input) def value_decode(self, val): val = val.strip('"') if not val: return None, val sig = HMAC.new(self.secret, val[40:].encode('utf-8'), SHA1).hexdigest() # Avoid timing attacks invalid_bits = 0 input_sig = val[:40] if len(sig) != len(input_sig): return InvalidSignature, val for a, b in zip(sig, input_sig): invalid_bits += a != b if invalid_bits: return InvalidSignature, val else: return val[40:], val def value_encode(self, val): sig = HMAC.new(self.secret, val.encode('utf-8'), SHA1).hexdigest() return str(val), ("%s%s" % (sig, val)) class _ConfigurableSession(dict): """Provides support for configurable Session objects. Provides a way to ensure some properties of sessions are always available with pre-configured values when they are not available in the session cookie itself. """ def __init__(self, cookie_domain=None, cookie_path='/'): self._config = { '_domain': cookie_domain, '_path': cookie_path } def clear(self): """Clears Session data. Preserves session configuration.""" super(_ConfigurableSession, self).clear() self.update(self._config) class Session(_ConfigurableSession): """Session object that uses container package for storage. :param invalidate_corrupt: How to handle corrupt data when loading. When set to True, then corrupt data will be silently invalidated and a new session created, otherwise invalid data will cause an exception. :type invalidate_corrupt: bool :param use_cookies: Whether or not cookies should be created. When set to False, it is assumed the user will handle storing the session on their own. :type use_cookies: bool :param type: What data backend type should be used to store the underlying session data :param key: The name the cookie should be set to. :param timeout: How long session data is considered valid. This is used regardless of the cookie being present or not to determine whether session data is still valid. Can be set to None to disable session time out. :type timeout: int or None :param save_accessed_time: Whether beaker should save the session's access time (True) or only modification time (False). Defaults to True. :param cookie_expires: Expiration date for cookie :param cookie_domain: Domain to use for the cookie. :param cookie_path: Path to use for the cookie. :param data_serializer: If ``"json"`` or ``"pickle"`` should be used to serialize data. Can also be an object with ``loads` and ``dumps`` methods. By default ``"pickle"`` is used. :param secure: Whether or not the cookie should only be sent over SSL. :param httponly: Whether or not the cookie should only be accessible by the browser not by JavaScript. :param encrypt_key: The key to use for the local session encryption, if not provided the session will not be encrypted. :param validate_key: The key used to sign the local encrypted session :param encrypt_nonce_bits: Number of bits used to generate nonce for encryption key salt. For security reason this is 128bits be default. If you want to keep backward compatibility with sessions generated before 1.8.0 set this to 48. :param crypto_type: encryption module to use :param samesite: SameSite value for the cookie -- should be either 'Lax', 'Strict', or None. """ def __init__(self, request, id=None, invalidate_corrupt=False, use_cookies=True, type=None, data_dir=None, key='beaker.session.id', timeout=None, save_accessed_time=True, cookie_expires=True, cookie_domain=None, cookie_path='/', data_serializer='pickle', secret=None, secure=False, namespace_class=None, httponly=False, encrypt_key=None, validate_key=None, encrypt_nonce_bits=DEFAULT_NONCE_BITS, crypto_type='default', samesite='Lax', **namespace_args): _ConfigurableSession.__init__( self, cookie_domain=cookie_domain, cookie_path=cookie_path ) self.clear() if not type: if data_dir: self.type = 'file' else: self.type = 'memory' else: self.type = type self.namespace_class = namespace_class or clsmap[self.type] self.namespace_args = namespace_args self.request = request self.data_dir = data_dir self.key = key if timeout and not save_accessed_time: raise BeakerException("timeout requires save_accessed_time") self.timeout = timeout # If a timeout was provided, forward it to the backend too, so the backend # can automatically expire entries if it's supported. if self.timeout is not None: # The backend expiration should always be a bit longer than the # session expiration itself to prevent the case where the backend data expires while # the session is being read (PR#153). 2 Minutes seems a reasonable time. self.namespace_args['timeout'] = self.timeout + 60 * 2 self.save_atime = save_accessed_time self.use_cookies = use_cookies self.cookie_expires = cookie_expires self._set_serializer(data_serializer) # Default cookie domain/path self.was_invalidated = False self.secret = secret self.secure = secure self.httponly = httponly self.samesite = samesite self.encrypt_key = encrypt_key self.validate_key = validate_key self.encrypt_nonce_size = get_nonce_size(encrypt_nonce_bits) self.crypto_module = get_crypto_module(crypto_type) self.id = id self.accessed_dict = {} self.invalidate_corrupt = invalidate_corrupt if self.use_cookies: cookieheader = request.get('cookie', '') if secret: try: self.cookie = SignedCookie( secret, input=cookieheader, ) except http_cookies.CookieError: self.cookie = SignedCookie( secret, input=None, ) else: self.cookie = SimpleCookie(input=cookieheader) if not self.id and self.key in self.cookie: cookie_data = self.cookie[self.key].value # Should we check invalidate_corrupt here? if cookie_data is InvalidSignature: cookie_data = None self.id = cookie_data self.is_new = self.id is None if self.is_new: self._create_id() self['_accessed_time'] = self['_creation_time'] = time.time() else: try: self.load() except Exception as e: if self.invalidate_corrupt: util.warn( "Invalidating corrupt session %s; " "error was: %s. Set invalidate_corrupt=False " "to propagate this exception." % (self.id, e)) self.invalidate() else: raise def _set_serializer(self, data_serializer): self.data_serializer = data_serializer if self.data_serializer == 'json': self.serializer = util.JsonSerializer() elif self.data_serializer == 'pickle': self.serializer = util.PickleSerializer() elif isinstance(self.data_serializer, string_type): raise BeakerException('Invalid value for data_serializer: %s' % data_serializer) else: self.serializer = data_serializer def has_key(self, name): return name in self def _set_cookie_values(self, expires=None): self.cookie[self.key] = self.id if self.domain: self.cookie[self.key]['domain'] = self.domain if self.secure: self.cookie[self.key]['secure'] = True if self.samesite: self.cookie[self.key]['samesite'] = self.samesite self._set_cookie_http_only() self.cookie[self.key]['path'] = self.path self._set_cookie_expires(expires) @staticmethod def serialize_cookie_date(v): v = v.timetuple() r = time.strftime("%%s, %d-%%s-%Y %H:%M:%S GMT", v) return r % (weekdays[v[6]], months[v[1]]) def _set_cookie_expires(self, expires): if expires is None: expires = self.cookie_expires if expires is False: expires_date = datetime.fromtimestamp(0x7FFFFFFF) elif isinstance(expires, timedelta): expires_date = datetime.utcnow() + expires elif isinstance(expires, datetime): expires_date = expires elif expires is not True: raise ValueError("Invalid argument for cookie_expires: %s" % repr(self.cookie_expires)) self.cookie_expires = expires if not self.cookie or self.key not in self.cookie: self.cookie[self.key] = self.id if expires is True: self.cookie[self.key]['expires'] = '' return True self.cookie[self.key]['expires'] = \ self.serialize_cookie_date(expires_date) return expires_date def _update_cookie_out(self, set_cookie=True): self._set_cookie_values() cookie_out = self.cookie[self.key].output(header='') if not isinstance(cookie_out, str): cookie_out = cookie_out.encode('latin1') self.request['cookie_out'] = cookie_out self.request['set_cookie'] = set_cookie def _set_cookie_http_only(self): try: if self.httponly: self.cookie[self.key]['httponly'] = True except http_cookies.CookieError as e: if 'Invalid Attribute httponly' not in str(e): raise util.warn('Python 2.6+ is required to use httponly') def _create_id(self, set_new=True): self.id = _session_id() if set_new: self.is_new = True self.last_accessed = None if self.use_cookies: sc = set_new is False self._update_cookie_out(set_cookie=sc) @property def created(self): return self['_creation_time'] def _set_domain(self, domain): self['_domain'] = domain self._update_cookie_out() def _get_domain(self): return self['_domain'] domain = property(_get_domain, _set_domain) def _set_path(self, path): self['_path'] = path self._update_cookie_out() def _get_path(self): return self.get('_path', '/') path = property(_get_path, _set_path) def _encrypt_data(self, session_data=None): """Serialize, encipher, and base64 the session dict""" session_data = session_data or self.copy() if self.encrypt_key: nonce_len, nonce_b64len = self.encrypt_nonce_size nonce = b64encode(os.urandom(nonce_len))[:nonce_b64len] encrypt_key = crypto.generateCryptoKeys(self.encrypt_key, self.validate_key + nonce, 1, self.crypto_module.getKeyLength()) data = self.serializer.dumps(session_data) return nonce + b64encode(self.crypto_module.aesEncrypt(data, encrypt_key)) else: data = self.serializer.dumps(session_data) return b64encode(data) def _decrypt_data(self, session_data): """Base64, decipher, then un-serialize the data for the session dict""" if self.encrypt_key: __, nonce_b64len = self.encrypt_nonce_size nonce = session_data[:nonce_b64len] encrypt_key = crypto.generateCryptoKeys(self.encrypt_key, self.validate_key + nonce, 1, self.crypto_module.getKeyLength()) payload = b64decode(session_data[nonce_b64len:]) data = self.crypto_module.aesDecrypt(payload, encrypt_key) else: data = b64decode(session_data) return self.serializer.loads(data) def _delete_cookie(self): self.request['set_cookie'] = True expires = datetime.utcnow() - timedelta(365) self._set_cookie_values(expires) self._update_cookie_out() def delete(self): """Deletes the session from the persistent storage, and sends an expired cookie out""" if self.use_cookies: self._delete_cookie() self.clear() def invalidate(self): """Invalidates this session, creates a new session id, returns to the is_new state""" self.clear() self.was_invalidated = True self._create_id() self.load() def load(self): "Loads the data from this session from persistent storage" self.namespace = self.namespace_class(self.id, data_dir=self.data_dir, digest_filenames=False, **self.namespace_args) now = time.time() if self.use_cookies: self.request['set_cookie'] = True self.namespace.acquire_read_lock() timed_out = False try: self.clear() try: session_data = self.namespace['session'] if (session_data is not None and self.encrypt_key): session_data = self._decrypt_data(session_data) # Memcached always returns a key, its None when its not # present if session_data is None: session_data = { '_creation_time': now, '_accessed_time': now } self.is_new = True except (KeyError, TypeError): session_data = { '_creation_time': now, '_accessed_time': now } self.is_new = True if session_data is None or len(session_data) == 0: session_data = { '_creation_time': now, '_accessed_time': now } self.is_new = True if self.timeout is not None and \ now - session_data['_accessed_time'] > self.timeout: timed_out = True else: # Properly set the last_accessed time, which is different # than the *currently* _accessed_time if self.is_new or '_accessed_time' not in session_data: self.last_accessed = None else: self.last_accessed = session_data['_accessed_time'] # Update the current _accessed_time session_data['_accessed_time'] = now self.update(session_data) self.accessed_dict = session_data.copy() finally: self.namespace.release_read_lock() if timed_out: self.invalidate() def save(self, accessed_only=False): """Saves the data for this session to persistent storage If accessed_only is True, then only the original data loaded at the beginning of the request will be saved, with the updated last accessed time. """ # Look to see if its a new session that was only accessed # Don't save it under that case if accessed_only and (self.is_new or not self.save_atime): return None # this session might not have a namespace yet or the session id # might have been regenerated if not hasattr(self, 'namespace') or self.namespace.namespace != self.id: self.namespace = self.namespace_class( self.id, data_dir=self.data_dir, digest_filenames=False, **self.namespace_args) self.namespace.acquire_write_lock(replace=True) try: if accessed_only: data = dict(self.accessed_dict.items()) else: data = dict(self.items()) if self.encrypt_key: data = self._encrypt_data(data) # Save the data if not data and 'session' in self.namespace: del self.namespace['session'] else: self.namespace['session'] = data finally: self.namespace.release_write_lock() if self.use_cookies and self.is_new: self.request['set_cookie'] = True def revert(self): """Revert the session to its original state from its first access in the request""" self.clear() self.update(self.accessed_dict) def regenerate_id(self): """ creates a new session id, retains all session data Its a good security practice to regnerate the id after a client elevates privileges. """ self._create_id(set_new=False) # TODO: I think both these methods should be removed. They're from # the original mod_python code i was ripping off but they really # have no use here. def lock(self): """Locks this session against other processes/threads. This is automatic when load/save is called. ***use with caution*** and always with a corresponding 'unlock' inside a "finally:" block, as a stray lock typically cannot be unlocked without shutting down the whole application. """ self.namespace.acquire_write_lock() def unlock(self): """Unlocks this session against other processes/threads. This is automatic when load/save is called. ***use with caution*** and always within a "finally:" block, as a stray lock typically cannot be unlocked without shutting down the whole application. """ self.namespace.release_write_lock() class CookieSession(Session): """Pure cookie-based session Options recognized when using cookie-based sessions are slightly more restricted than general sessions. :param key: The name the cookie should be set to. :param timeout: How long session data is considered valid. This is used regardless of the cookie being present or not to determine whether session data is still valid. :type timeout: int :param save_accessed_time: Whether beaker should save the session's access time (True) or only modification time (False). Defaults to True. :param cookie_expires: Expiration date for cookie :param cookie_domain: Domain to use for the cookie. :param cookie_path: Path to use for the cookie. :param data_serializer: If ``"json"`` or ``"pickle"`` should be used to serialize data. Can also be an object with ``loads` and ``dumps`` methods. By default ``"pickle"`` is used. :param secure: Whether or not the cookie should only be sent over SSL. :param httponly: Whether or not the cookie should only be accessible by the browser not by JavaScript. :param encrypt_key: The key to use for the local session encryption, if not provided the session will not be encrypted. :param validate_key: The key used to sign the local encrypted session :param invalidate_corrupt: How to handle corrupt data when loading. When set to True, then corrupt data will be silently invalidated and a new session created, otherwise invalid data will cause an exception. :type invalidate_corrupt: bool :param crypto_type: The crypto module to use. :param samesite: SameSite value for the cookie -- should be either 'Lax', 'Strict', or None. """ def __init__(self, request, key='beaker.session.id', timeout=None, save_accessed_time=True, cookie_expires=True, cookie_domain=None, cookie_path='/', encrypt_key=None, validate_key=None, secure=False, httponly=False, data_serializer='pickle', encrypt_nonce_bits=DEFAULT_NONCE_BITS, invalidate_corrupt=False, crypto_type='default', samesite='Lax', **kwargs): _ConfigurableSession.__init__( self, cookie_domain=cookie_domain, cookie_path=cookie_path ) self.clear() self.crypto_module = get_crypto_module(crypto_type) if encrypt_key and not self.crypto_module.has_aes: raise InvalidCryptoBackendError("No AES library is installed, can't generate " "encrypted cookie-only Session.") self.request = request self.key = key self.timeout = timeout self.save_atime = save_accessed_time self.cookie_expires = cookie_expires self.encrypt_key = encrypt_key self.validate_key = validate_key self.encrypt_nonce_size = get_nonce_size(encrypt_nonce_bits) self.request['set_cookie'] = False self.secure = secure self.httponly = httponly self.samesite = samesite self.invalidate_corrupt = invalidate_corrupt self._set_serializer(data_serializer) try: cookieheader = request['cookie'] except KeyError: cookieheader = '' if validate_key is None: raise BeakerException("No validate_key specified for Cookie only " "Session.") if timeout and not save_accessed_time: raise BeakerException("timeout requires save_accessed_time") try: self.cookie = SignedCookie( validate_key, input=cookieheader, ) except http_cookies.CookieError: self.cookie = SignedCookie( validate_key, input=None, ) self['_id'] = _session_id() self.is_new = True # If we have a cookie, load it if self.key in self.cookie and self.cookie[self.key].value is not None: self.is_new = False try: cookie_data = self.cookie[self.key].value if cookie_data is InvalidSignature: raise BeakerException("Invalid signature") self.update(self._decrypt_data(cookie_data)) except Exception as e: if self.invalidate_corrupt: util.warn( "Invalidating corrupt session %s; " "error was: %s. Set invalidate_corrupt=False " "to propagate this exception." % (self.id, e)) self.invalidate() else: raise if self.timeout is not None: now = time.time() last_accessed_time = self.get('_accessed_time', now) if now - last_accessed_time > self.timeout: self.clear() self.accessed_dict = self.copy() self._create_cookie() def created(self): return self['_creation_time'] created = property(created) def id(self): return self['_id'] id = property(id) def _set_domain(self, domain): self['_domain'] = domain def _get_domain(self): return self['_domain'] domain = property(_get_domain, _set_domain) def _set_path(self, path): self['_path'] = path def _get_path(self): return self['_path'] path = property(_get_path, _set_path) def save(self, accessed_only=False): """Saves the data for this session to persistent storage""" if accessed_only and (self.is_new or not self.save_atime): return if accessed_only: self.clear() self.update(self.accessed_dict) self._create_cookie() def expire(self): """Delete the 'expires' attribute on this Session, if any.""" self.pop('_expires', None) def _create_cookie(self): if '_creation_time' not in self: self['_creation_time'] = time.time() if '_id' not in self: self['_id'] = _session_id() self['_accessed_time'] = time.time() val = self._encrypt_data() if len(val) > 4064: raise BeakerException("Cookie value is too long to store") self.cookie[self.key] = val if '_expires' in self: expires = self['_expires'] else: expires = None expires = self._set_cookie_expires(expires) if expires is not None: self['_expires'] = expires if self.domain: self.cookie[self.key]['domain'] = self.domain if self.secure: self.cookie[self.key]['secure'] = True if self.samesite: self.cookie[self.key]['samesite'] = self.samesite self._set_cookie_http_only() self.cookie[self.key]['path'] = self.get('_path', '/') cookie_out = self.cookie[self.key].output(header='') if not isinstance(cookie_out, str): cookie_out = cookie_out.encode('latin1') self.request['cookie_out'] = cookie_out self.request['set_cookie'] = True def delete(self): """Delete the cookie, and clear the session""" # Send a delete cookie request self._delete_cookie() self.clear() def invalidate(self): """Clear the contents and start a new session""" self.clear() self['_id'] = _session_id() class SessionObject(object): """Session proxy/lazy creator This object proxies access to the actual session object, so that in the case that the session hasn't been used before, it will be setup. This avoid creating and loading the session from persistent storage unless its actually used during the request. """ def __init__(self, environ, **params): self.__dict__['_params'] = params self.__dict__['_environ'] = environ self.__dict__['_sess'] = None self.__dict__['_headers'] = {} def _session(self): """Lazy initial creation of session object""" if self.__dict__['_sess'] is None: params = self.__dict__['_params'] environ = self.__dict__['_environ'] self.__dict__['_headers'] = req = {'cookie_out': None} req['cookie'] = environ.get('HTTP_COOKIE') session_cls = params.get('session_class', None) if session_cls is None: if params.get('type') == 'cookie': session_cls = CookieSession else: session_cls = Session else: assert issubclass(session_cls, Session),\ "Not a Session: " + session_cls self.__dict__['_sess'] = session_cls(req, **params) return self.__dict__['_sess'] def __getattr__(self, attr): return getattr(self._session(), attr) def __setattr__(self, attr, value): setattr(self._session(), attr, value) def __delattr__(self, name): self._session().__delattr__(name) def __getitem__(self, key): return self._session()[key] def __setitem__(self, key, value): self._session()[key] = value def __delitem__(self, key): self._session().__delitem__(key) def __repr__(self): return self._session().__repr__() def __iter__(self): """Only works for proxying to a dict""" return iter(self._session().keys()) def __contains__(self, key): return key in self._session() def has_key(self, key): return key in self._session() def get_by_id(self, id): """Loads a session given a session ID""" params = self.__dict__['_params'] session = Session({}, use_cookies=False, id=id, **params) if session.is_new: return None return session def save(self): self.__dict__['_dirty'] = True def delete(self): self.__dict__['_dirty'] = True self._session().delete() def persist(self): """Persist the session to the storage Always saves the whole session if save() or delete() have been called. If they haven't: - If autosave is set to true, saves the the entire session regardless. - If save_accessed_time is set to true or unset, only saves the updated access time. - If save_accessed_time is set to false, doesn't save anything. """ if self.__dict__['_params'].get('auto'): self._session().save() elif self.__dict__['_params'].get('save_accessed_time', True): if self.dirty(): self._session().save() else: self._session().save(accessed_only=True) else: # save_accessed_time is false if self.dirty(): self._session().save() def dirty(self): """Returns True if save() or delete() have been called""" return self.__dict__.get('_dirty', False) def accessed(self): """Returns whether or not the session has been accessed""" return self.__dict__['_sess'] is not None Submit