"""Authenticating services with JupyterHub. Tokens are sent to the Hub for verification. The Hub replies with a JSON model describing the authenticated user. ``HubAuth`` can be used in any application, even outside tornado. ``HubAuthenticated`` is a mixin class for tornado handlers that should authenticate with the Hub. """ import base64 import hashlib import json import os import random import re import socket import string import time import uuid import warnings from unittest import mock from urllib.parse import urlencode import requests from tornado.httputil import url_concat from tornado.log import app_log from tornado.web import HTTPError from tornado.web import RequestHandler from traitlets import default from traitlets import Dict from traitlets import Instance from traitlets import Integer from traitlets import observe from traitlets import Set from traitlets import Unicode from traitlets import validate from traitlets.config import SingletonConfigurable from ..scopes import _intersect_expanded_scopes from ..utils import url_path_join def check_scopes(required_scopes, scopes): """Check that required_scope(s) are in scopes Returns the subset of scopes matching required_scopes, which is truthy if any scopes match any required scopes. Correctly resolves scope filters *except* for groups -> user, e.g. require: access:server!user=x, have: access:server!group=y will not grant access to user x even if user x is in group y. Parameters ---------- required_scopes: set The set of scopes required. scopes: set The set (or list) of scopes to check against required_scopes Returns ------- relevant_scopes: set The set of scopes in required_scopes that are present in scopes, which is truthy if any required scopes are present, and falsy otherwise. """ if isinstance(required_scopes, str): required_scopes = {required_scopes} intersection = _intersect_expanded_scopes(required_scopes, scopes) # re-intersect with required_scopes in case the intersection # applies stricter filters than required_scopes declares # e.g. required_scopes = {'read:users'} and intersection has only {'read:users!user=x'} return set(required_scopes) & intersection class _ExpiringDict(dict): """Dict-like cache for Hub API requests Values will expire after max_age seconds. A monotonic timer is used (time.monotonic). A max_age of 0 means cache forever. """ max_age = 0 def __init__(self, max_age=0): self.max_age = max_age self.timestamps = {} self.values = {} def __setitem__(self, key, value): """Store key and record timestamp""" self.timestamps[key] = time.monotonic() self.values[key] = value def __repr__(self): """include values and timestamps in repr""" now = time.monotonic() return repr( { key: '{value} (age={age:.0f}s)'.format( value=repr(value)[:16] + '...', age=now - self.timestamps[key] ) for key, value in self.values.items() } ) def _check_age(self, key): """Check timestamp for a key""" if key not in self.values: # not registered, nothing to do return now = time.monotonic() timestamp = self.timestamps[key] if self.max_age > 0 and timestamp + self.max_age < now: self.values.pop(key) self.timestamps.pop(key) def __contains__(self, key): """dict check for `key in dict`""" self._check_age(key) return key in self.values def __getitem__(self, key): """Check age before returning value""" self._check_age(key) return self.values[key] def get(self, key, default=None): """dict-like get:""" try: return self[key] except KeyError: return default def clear(self): """Clear the cache""" self.values.clear() self.timestamps.clear() class HubAuth(SingletonConfigurable): """A class for authenticating with JupyterHub This can be used by any application. Use this base class only for direct, token-authenticated applications (web APIs). For applications that support direct visits from browsers, use HubOAuth to enable OAuth redirect-based authentication. If using tornado, use via :class:`HubAuthenticated` mixin. If using manually, use the ``.user_for_token(token_value)`` method to identify the user owning a given token. The following config must be set: - api_token (token for authenticating with JupyterHub API), fetched from the JUPYTERHUB_API_TOKEN env by default. The following config MAY be set: - api_url: the base URL of the Hub's internal API, fetched from JUPYTERHUB_API_URL by default. - cookie_cache_max_age: the number of seconds responses from the Hub should be cached. - login_url (the *public* ``/hub/login`` URL of the Hub). """ hub_host = Unicode( '', help="""The public host of JupyterHub Only used if JupyterHub is spreading servers across subdomains. """, ).tag(config=True) @default('hub_host') def _default_hub_host(self): return os.getenv('JUPYTERHUB_HOST', '') base_url = Unicode( os.getenv('JUPYTERHUB_SERVICE_PREFIX') or '/', help="""The base URL prefix of this application e.g. /services/service-name/ or /user/name/ Default: get from JUPYTERHUB_SERVICE_PREFIX """, ).tag(config=True) @validate('base_url') def _add_slash(self, proposal): """Ensure base_url starts and ends with /""" value = proposal['value'] if not value.startswith('/'): value = '/' + value if not value.endswith('/'): value = value + '/' return value # where is the hub api_url = Unicode( os.getenv('JUPYTERHUB_API_URL') or 'http://127.0.0.1:8081/hub/api', help="""The base API URL of the Hub. Typically `http://hub-ip:hub-port/hub/api` """, ).tag(config=True) @default('api_url') def _api_url(self): env_url = os.getenv('JUPYTERHUB_API_URL') if env_url: return env_url else: return 'http://127.0.0.1:8081' + url_path_join(self.hub_prefix, 'api') api_token = Unicode( os.getenv('JUPYTERHUB_API_TOKEN', ''), help="""API key for accessing Hub API. Generate with `jupyterhub token [username]` or add to JupyterHub.services config. """, ).tag(config=True) hub_prefix = Unicode( '/hub/', help="""The URL prefix for the Hub itself. Typically /hub/ """, ).tag(config=True) @default('hub_prefix') def _default_hub_prefix(self): return url_path_join(os.getenv('JUPYTERHUB_BASE_URL') or '/', 'hub') + '/' login_url = Unicode( '/hub/login', help="""The login URL to use Typically /hub/login """, ).tag(config=True) @default('login_url') def _default_login_url(self): return self.hub_host + url_path_join(self.hub_prefix, 'login') keyfile = Unicode( os.getenv('JUPYTERHUB_SSL_KEYFILE', ''), help="""The ssl key to use for requests Use with certfile """, ).tag(config=True) certfile = Unicode( os.getenv('JUPYTERHUB_SSL_CERTFILE', ''), help="""The ssl cert to use for requests Use with keyfile """, ).tag(config=True) client_ca = Unicode( os.getenv('JUPYTERHUB_SSL_CLIENT_CA', ''), help="""The ssl certificate authority to use to verify requests Use with keyfile and certfile """, ).tag(config=True) cookie_options = Dict( help="""Additional options to pass when setting cookies. Can include things like `expires_days=None` for session-expiry or `secure=True` if served on HTTPS and default HTTPS discovery fails (e.g. behind some proxies). """ ).tag(config=True) @default('cookie_options') def _default_cookie_options(self): # load default from env options_env = os.environ.get('JUPYTERHUB_COOKIE_OPTIONS') if options_env: return json.loads(options_env) else: return {} cookie_cache_max_age = Integer(help="DEPRECATED. Use cache_max_age") @observe('cookie_cache_max_age') def _deprecated_cookie_cache(self, change): warnings.warn( "cookie_cache_max_age is deprecated in JupyterHub 0.8. Use cache_max_age instead." ) self.cache_max_age = change.new cache_max_age = Integer( 300, help="""The maximum time (in seconds) to cache the Hub's responses for authentication. A larger value reduces load on the Hub and occasional response lag. A smaller value reduces propagation time of changes on the Hub (rare). Default: 300 (five minutes) """, ).tag(config=True) cache = Instance(_ExpiringDict, allow_none=False) @default('cache') def _default_cache(self): return _ExpiringDict(self.cache_max_age) oauth_scopes = Set( Unicode(), help="""OAuth scopes to use for allowing access. Get from $JUPYTERHUB_OAUTH_SCOPES by default. """, ).tag(config=True) @default('oauth_scopes') def _default_scopes(self): env_scopes = os.getenv('JUPYTERHUB_OAUTH_SCOPES') if env_scopes: return set(json.loads(env_scopes)) service_name = os.getenv("JUPYTERHUB_SERVICE_NAME") if service_name: return {f'access:services!service={service_name}'} return set() def _check_hub_authorization(self, url, api_token, cache_key=None, use_cache=True): """Identify a user with the Hub Args: url (str): The API URL to check the Hub for authorization (e.g. http://127.0.0.1:8081/hub/api/user) cache_key (str): The key for checking the cache use_cache (bool): Specify use_cache=False to skip cached cookie values (default: True) Returns: user_model (dict): The user model, if a user is identified, None if authentication fails. Raises an HTTPError if the request failed for a reason other than no such user. """ if use_cache: if cache_key is None: raise ValueError("cache_key is required when using cache") # check for a cached reply, so we don't check with the Hub if we don't have to try: return self.cache[cache_key] except KeyError: app_log.debug("HubAuth cache miss: %s", cache_key) data = self._api_request( 'GET', url, headers={"Authorization": "token " + api_token}, allow_403=True, ) if data is None: app_log.warning("No Hub user identified for request") else: app_log.debug("Received request from Hub user %s", data) if use_cache: # cache result self.cache[cache_key] = data return data def _api_request(self, method, url, **kwargs): """Make an API request""" allow_403 = kwargs.pop('allow_403', False) headers = kwargs.setdefault('headers', {}) headers.setdefault('Authorization', 'token %s' % self.api_token) if "cert" not in kwargs and self.certfile and self.keyfile: kwargs["cert"] = (self.certfile, self.keyfile) if self.client_ca: kwargs["verify"] = self.client_ca try: r = requests.request(method, url, **kwargs) except requests.ConnectionError as e: app_log.error("Error connecting to %s: %s", self.api_url, e) msg = "Failed to connect to Hub API at %r." % self.api_url msg += ( " Is the Hub accessible at this URL (from host: %s)?" % socket.gethostname() ) if '127.0.0.1' in self.api_url: msg += ( " Make sure to set c.JupyterHub.hub_ip to an IP accessible to" + " single-user servers if the servers are not on the same host as the Hub." ) raise HTTPError(500, msg) data = None if r.status_code == 403 and allow_403: pass elif r.status_code == 403: app_log.error( "I don't have permission to check authorization with JupyterHub, my auth token may have expired: [%i] %s", r.status_code, r.reason, ) app_log.error(r.text) raise HTTPError( 500, "Permission failure checking authorization, I may need a new token" ) elif r.status_code >= 500: app_log.error( "Upstream failure verifying auth token: [%i] %s", r.status_code, r.reason, ) app_log.error(r.text) raise HTTPError(502, "Failed to check authorization (upstream problem)") elif r.status_code >= 400: app_log.warning( "Failed to check authorization: [%i] %s", r.status_code, r.reason ) app_log.warning(r.text) msg = "Failed to check authorization" # pass on error from oauth failure try: response = r.json() # prefer more specific 'error_description', fallback to 'error' description = response.get( "error_description", response.get("error", "Unknown error") ) except Exception: pass else: msg += ": " + description raise HTTPError(500, msg) else: data = r.json() return data def user_for_cookie(self, encrypted_cookie, use_cache=True, session_id=''): """Deprecated and removed. Use HubOAuth to authenticate browsers.""" raise RuntimeError( "Identifying users by shared cookie is removed in JupyterHub 2.0. Use OAuth tokens." ) def user_for_token(self, token, use_cache=True, session_id=''): """Ask the Hub to identify the user for a given token. Args: token (str): the token use_cache (bool): Specify use_cache=False to skip cached cookie values (default: True) Returns: user_model (dict): The user model, if a user is identified, None if authentication fails. The 'name' field contains the user's name. """ return self._check_hub_authorization( url=url_path_join( self.api_url, "user", ), api_token=token, cache_key='token:{}:{}'.format( session_id, hashlib.sha256(token.encode("utf8", "replace")).hexdigest(), ), use_cache=use_cache, ) auth_header_name = 'Authorization' auth_header_pat = re.compile(r'(?:token|bearer)\s+(.+)', re.IGNORECASE) def get_token(self, handler): """Get the user token from a request - in URL parameters: ?token= - in header: Authorization: token """ user_token = handler.get_argument('token', '') if not user_token: # get it from Authorization header m = self.auth_header_pat.match( handler.request.headers.get(self.auth_header_name, '') ) if m: user_token = m.group(1) return user_token def _get_user_cookie(self, handler): """Get the user model from a cookie""" # overridden in HubOAuth to store the access token after oauth return None def get_session_id(self, handler): """Get the jupyterhub session id from the jupyterhub-session-id cookie. """ return handler.get_cookie('jupyterhub-session-id', '') def get_user(self, handler): """Get the Hub user for a given tornado handler. Checks cookie with the Hub to identify the current user. Args: handler (tornado.web.RequestHandler): the current request handler Returns: user_model (dict): The user model, if a user is identified, None if authentication fails. The 'name' field contains the user's name. """ # only allow this to be called once per handler # avoids issues if an error is raised, # since this may be called again when trying to render the error page if hasattr(handler, '_cached_hub_user'): return handler._cached_hub_user handler._cached_hub_user = user_model = None session_id = self.get_session_id(handler) # check token first token = self.get_token(handler) if token: user_model = self.user_for_token(token, session_id=session_id) if user_model: handler._token_authenticated = True # no token, check cookie if user_model is None: user_model = self._get_user_cookie(handler) # cache result handler._cached_hub_user = user_model if not user_model: app_log.debug("No user identified") return user_model def check_scopes(self, required_scopes, user): """Check whether the user has required scope(s)""" return check_scopes(required_scopes, set(user["scopes"])) class HubOAuth(HubAuth): """HubAuth using OAuth for login instead of cookies set by the Hub. Use this class if you want users to be able to visit your service with a browser. They will be authenticated via OAuth with the Hub. .. versionadded: 0.8 """ # Overrides of HubAuth API @default('login_url') def _login_url(self): return url_concat( self.oauth_authorization_url, { 'client_id': self.oauth_client_id, 'redirect_uri': self.oauth_redirect_uri, 'response_type': 'code', }, ) @property def cookie_name(self): """Use OAuth client_id for cookie name because we don't want to use the same cookie name across OAuth clients. """ return self.oauth_client_id @property def state_cookie_name(self): """The cookie name for storing OAuth state This cookie is only live for the duration of the OAuth handshake. """ return self.cookie_name + '-oauth-state' def _get_user_cookie(self, handler): token = handler.get_secure_cookie(self.cookie_name) session_id = self.get_session_id(handler) if token: token = token.decode('ascii', 'replace') user_model = self.user_for_token(token, session_id=session_id) if user_model is None: app_log.warning("Token stored in cookie may have expired") handler.clear_cookie(self.cookie_name) return user_model # HubOAuth API oauth_client_id = Unicode( help="""The OAuth client ID for this application. Use JUPYTERHUB_CLIENT_ID by default. """ ).tag(config=True) @default('oauth_client_id') def _client_id(self): return os.getenv('JUPYTERHUB_CLIENT_ID', '') @validate('oauth_client_id', 'api_token') def _ensure_not_empty(self, proposal): if not proposal.value: raise ValueError("%s cannot be empty." % proposal.trait.name) return proposal.value oauth_redirect_uri = Unicode( help="""OAuth redirect URI Should generally be /base_url/oauth_callback """ ).tag(config=True) @default('oauth_redirect_uri') def _default_redirect(self): return os.getenv('JUPYTERHUB_OAUTH_CALLBACK_URL') or url_path_join( self.base_url, 'oauth_callback' ) oauth_authorization_url = Unicode( '/hub/api/oauth2/authorize', help="The URL to redirect to when starting the OAuth process", ).tag(config=True) @default('oauth_authorization_url') def _auth_url(self): return self.hub_host + url_path_join(self.hub_prefix, 'api/oauth2/authorize') oauth_token_url = Unicode( help="""The URL for requesting an OAuth token from JupyterHub""" ).tag(config=True) @default('oauth_token_url') def _token_url(self): return url_path_join(self.api_url, 'oauth2/token') def token_for_code(self, code): """Get token for OAuth temporary code This is the last step of OAuth login. Should be called in OAuth Callback handler. Args: code (str): oauth code for finishing OAuth login Returns: token (str): JupyterHub API Token """ # GitHub specifies a POST request yet requires URL parameters params = dict( client_id=self.oauth_client_id, client_secret=self.api_token, grant_type='authorization_code', code=code, redirect_uri=self.oauth_redirect_uri, ) token_reply = self._api_request( 'POST', self.oauth_token_url, data=urlencode(params).encode('utf8'), headers={'Content-Type': 'application/x-www-form-urlencoded'}, ) return token_reply['access_token'] def _encode_state(self, state): """Encode a state dict as url-safe base64""" # trim trailing `=` because = is itself not url-safe! json_state = json.dumps(state) return ( base64.urlsafe_b64encode(json_state.encode('utf8')) .decode('ascii') .rstrip('=') ) def _decode_state(self, b64_state): """Decode a base64 state Always returns a dict. The dict will be empty if the state is invalid. """ if isinstance(b64_state, str): b64_state = b64_state.encode('ascii') if len(b64_state) != 4: # restore padding b64_state = b64_state + (b'=' * (4 - len(b64_state) % 4)) try: json_state = base64.urlsafe_b64decode(b64_state).decode('utf8') except ValueError: app_log.error("Failed to b64-decode state: %r", b64_state) return {} try: return json.loads(json_state) except ValueError: app_log.error("Failed to json-decode state: %r", json_state) return {} def set_state_cookie(self, handler, next_url=None): """Generate an OAuth state and store it in a cookie Parameters ---------- handler : RequestHandler A tornado RequestHandler next_url : str The page to redirect to on successful login Returns ------- state : str The OAuth state that has been stored in the cookie (url safe, base64-encoded) """ extra_state = {} if handler.get_cookie(self.state_cookie_name): # oauth state cookie is already set # use a randomized cookie suffix to avoid collisions # in case of concurrent logins app_log.warning("Detected unused OAuth state cookies") cookie_suffix = ''.join( random.choice(string.ascii_letters) for i in range(8) ) cookie_name = f'{self.state_cookie_name}-{cookie_suffix}' extra_state['cookie_name'] = cookie_name else: cookie_name = self.state_cookie_name b64_state = self.generate_state(next_url, **extra_state) kwargs = { 'path': self.base_url, 'httponly': True, # Expire oauth state cookie in ten minutes. # Usually this will be cleared by completed login # in less than a few seconds. # OAuth that doesn't complete shouldn't linger too long. 'max_age': 600, } if handler.request.protocol == 'https': kwargs['secure'] = True # load user cookie overrides kwargs.update(self.cookie_options) handler.set_secure_cookie(cookie_name, b64_state, **kwargs) return b64_state def generate_state(self, next_url=None, **extra_state): """Generate a state string, given a next_url redirect target Parameters ---------- next_url : str The URL of the page to redirect to on successful login. Returns ------- state (str): The base64-encoded state string. """ state = {'uuid': uuid.uuid4().hex, 'next_url': next_url} state.update(extra_state) return self._encode_state(state) def get_next_url(self, b64_state=''): """Get the next_url for redirection, given an encoded OAuth state""" state = self._decode_state(b64_state) return state.get('next_url') or self.base_url def get_state_cookie_name(self, b64_state=''): """Get the cookie name for oauth state, given an encoded OAuth state Cookie name is stored in the state itself because the cookie name is randomized to deal with races between concurrent oauth sequences. """ state = self._decode_state(b64_state) return state.get('cookie_name') or self.state_cookie_name def set_cookie(self, handler, access_token): """Set a cookie recording OAuth result""" kwargs = {'path': self.base_url, 'httponly': True} if handler.request.protocol == 'https': kwargs['secure'] = True # load user cookie overrides kwargs.update(self.cookie_options) app_log.debug( "Setting oauth cookie for %s: %s, %s", handler.request.remote_ip, self.cookie_name, kwargs, ) handler.set_secure_cookie(self.cookie_name, access_token, **kwargs) def clear_cookie(self, handler): """Clear the OAuth cookie""" handler.clear_cookie(self.cookie_name, path=self.base_url) class UserNotAllowed(Exception): """Exception raised when a user is identified and not allowed""" def __init__(self, model): self.model = model def __str__(self): return '<{cls} {kind}={name}>'.format( cls=self.__class__.__name__, kind=self.model['kind'], name=self.model['name'], ) class HubAuthenticated: """Mixin for tornado handlers that are authenticated with JupyterHub A handler that mixes this in must have the following attributes/properties: - .hub_auth: A HubAuth instance - .hub_scopes: A set of JupyterHub 2.0 OAuth scopes to allow. Default comes from .hub_auth.oauth_scopes, which in turn is set by $JUPYTERHUB_OAUTH_SCOPES Default values include: - 'access:services', 'access:services!service={service_name}' for services - 'access:servers', 'access:servers!user={user}', 'access:servers!server={user}/{server_name}' for single-user servers If hub_scopes is not used (e.g. JupyterHub 1.x), these additional properties can be used: - .allow_admin: If True, allow any admin user. Default: False. - .hub_users: A set of usernames to allow. If left unspecified or None, username will not be checked. - .hub_groups: A set of group names to allow. If left unspecified or None, groups will not be checked. - .allow_admin: Is admin user access allowed or not If left unspecified or False, admin user won't have an access. Examples:: class MyHandler(HubAuthenticated, web.RequestHandler): hub_users = {'inara', 'mal'} def initialize(self, hub_auth): self.hub_auth = hub_auth @web.authenticated def get(self): ... """ hub_services = None # set of allowed services hub_users = None # set of allowed users hub_groups = None # set of allowed groups allow_admin = False # allow any admin user access @property def hub_scopes(self): """Set of allowed scopes (use hub_auth.oauth_scopes by default)""" return self.hub_auth.oauth_scopes or None @property def allow_all(self): """Property indicating that all successfully identified user or service should be allowed. """ return ( self.hub_scopes is None and self.hub_services is None and self.hub_users is None and self.hub_groups is None and not self.allow_admin ) # self.hub_auth must be a HubAuth instance. # If nothing specified, use default config, # which will be configured with defaults # based on JupyterHub environment variables for services. _hub_auth = None hub_auth_class = HubAuth @property def hub_auth(self): if self._hub_auth is None: self._hub_auth = self.hub_auth_class.instance() return self._hub_auth @hub_auth.setter def hub_auth(self, auth): self._hub_auth = auth def get_login_url(self): """Return the Hub's login URL""" login_url = self.hub_auth.login_url if isinstance(self.hub_auth, HubOAuth): # add state argument to OAuth url state = self.hub_auth.set_state_cookie(self, next_url=self.request.uri) login_url = url_concat(login_url, {'state': state}) # temporary override at setting level, # to allow any subclass overrides of get_login_url to preserve their effect # for example, APIHandler raises 403 to prevent redirects with mock.patch.dict(self.application.settings, {"login_url": login_url}): app_log.debug("Redirecting to login url: %s", login_url) return super().get_login_url() def check_hub_user(self, model): """Check whether Hub-authenticated user or service should be allowed. Returns the input if the user should be allowed, None otherwise. Override for custom logic in authenticating users. Args: user_model (dict): the user or service model returned from :class:`HubAuth` Returns: user_model (dict): The user model if the user should be allowed, None otherwise. """ name = model['name'] kind = model.setdefault('kind', 'user') if self.allow_all: app_log.debug( "Allowing Hub %s %s (all Hub users and services allowed)", kind, name ) return model if self.hub_scopes: scopes = self.hub_auth.check_scopes(self.hub_scopes, model) if scopes: app_log.debug( f"Allowing Hub {kind} {name} based on oauth scopes {scopes}" ) return model else: app_log.warning( f"Not allowing Hub {kind} {name}: missing required scopes" ) app_log.debug( f"Hub {kind} {name} needs scope(s) {self.hub_scopes}, has scope(s) {model['scopes']}" ) # if hub_scopes are used, *only* hub_scopes are used # note: this means successful authentication, but insufficient permission raise UserNotAllowed(model) # proceed with the pre-2.0 way if hub_scopes is not set if self.allow_admin and model.get('admin', False): app_log.debug("Allowing Hub admin %s", name) return model if kind == 'service': # it's a service, check hub_services if self.hub_services and name in self.hub_services: app_log.debug("Allowing Hub service %s", name) return model else: app_log.warning("Not allowing Hub service %s", name) raise UserNotAllowed(model) if self.hub_users and name in self.hub_users: # user in allowed list app_log.debug("Allowing Hub user %s", name) return model elif self.hub_groups and set(model['groups']).intersection(self.hub_groups): allowed_groups = set(model['groups']).intersection(self.hub_groups) app_log.debug( "Allowing Hub user %s in group(s) %s", name, ','.join(sorted(allowed_groups)), ) # group in allowed list return model else: app_log.warning("Not allowing Hub user %s", name) raise UserNotAllowed(model) def get_current_user(self): """Tornado's authentication method Returns: user_model (dict): The user model, if a user is identified, None if authentication fails. """ if hasattr(self, '_hub_auth_user_cache'): return self._hub_auth_user_cache user_model = self.hub_auth.get_user(self) if not user_model: self._hub_auth_user_cache = None return try: self._hub_auth_user_cache = self.check_hub_user(user_model) except UserNotAllowed as e: # cache None, in case get_user is called again while processing the error self._hub_auth_user_cache = None # Override redirect so if/when tornado @web.authenticated # tries to redirect to login URL, 403 will be raised instead. # This is not the best, but avoids problems that can be caused # when get_current_user is allowed to raise. def raise_on_redirect(*args, **kwargs): raise HTTPError( 403, "{kind} {name} is not allowed.".format(**user_model) ) self.redirect = raise_on_redirect return except Exception: self._hub_auth_user_cache = None raise # store ?token=... tokens passed via url in a cookie for future requests url_token = self.get_argument('token', '') if ( user_model and url_token and getattr(self, '_token_authenticated', False) and hasattr(self.hub_auth, 'set_cookie') ): # authenticated via `?token=` # set a cookie for future requests # hub_auth.set_cookie is only available on HubOAuth self.hub_auth.set_cookie(self, url_token) return self._hub_auth_user_cache class HubOAuthenticated(HubAuthenticated): """Simple subclass of HubAuthenticated using OAuth instead of old shared cookies""" hub_auth_class = HubOAuth class HubOAuthCallbackHandler(HubOAuthenticated, RequestHandler): """OAuth Callback handler Finishes the OAuth flow, setting a cookie to record the user's info. Should be registered at ``SERVICE_PREFIX/oauth_callback`` .. versionadded: 0.8 """ async def get(self): error = self.get_argument("error", False) if error: msg = self.get_argument("error_description", error) raise HTTPError(400, "Error in oauth: %s" % msg) code = self.get_argument("code", False) if not code: raise HTTPError(400, "oauth callback made without a token") # validate OAuth state arg_state = self.get_argument("state", None) if arg_state is None: raise HTTPError(500, "oauth state is missing. Try logging in again.") cookie_name = self.hub_auth.get_state_cookie_name(arg_state) cookie_state = self.get_secure_cookie(cookie_name) # clear cookie state now that we've consumed it self.clear_cookie(cookie_name, path=self.hub_auth.base_url) if isinstance(cookie_state, bytes): cookie_state = cookie_state.decode('ascii', 'replace') # check that state matches if arg_state != cookie_state: app_log.warning("oauth state %r != %r", arg_state, cookie_state) raise HTTPError(403, "oauth state does not match. Try logging in again.") next_url = self.hub_auth.get_next_url(cookie_state) # TODO: make async (in a Thread?) token = self.hub_auth.token_for_code(code) session_id = self.hub_auth.get_session_id(self) user_model = self.hub_auth.user_for_token(token, session_id=session_id) if user_model is None: raise HTTPError(500, "oauth callback failed to identify a user") app_log.info("Logged-in user %s", user_model) self.hub_auth.set_cookie(self, token) self.redirect(next_url or self.hub_auth.base_url)