codekingpro/portable-devtools
114k
1import json2import base643import time4import random5import string6import warnings7import hashlib8import logging9 10from . import oauth211 12 13logger = logging.getLogger(__name__)14 15def decode_part(raw, encoding="utf-8"):16 """Decode a part of the JWT.17 18 JWT is encoded by padding-less base64url,19 based on `JWS specs <https://tools.ietf.org/html/rfc7515#appendix-C>`_.20 21 :param encoding:22 If you are going to decode the first 2 parts of a JWT, i.e. the header23 or the payload, the default value "utf-8" would work fine.24 If you are going to decode the last part i.e. the signature part,25 it is a binary string so you should use `None` as encoding here.26 """27 raw += '=' * (-len(raw) % 4) # https://stackoverflow.com/a/32517907/72867528 raw = str(29 # On Python 2.7, argument of urlsafe_b64decode must be str, not unicode.30 # This is not required on Python 3.31 raw)32 output = base64.urlsafe_b64decode(raw)33 if encoding:34 output = output.decode(encoding)35 return output36 37base64decode = decode_part # Obsolete. For backward compatibility only.38 39def _epoch_to_local(epoch):40 return time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(epoch))41 42class IdTokenError(RuntimeError): # We waised RuntimeError before, so keep it43 """In unlikely event of an ID token is malformed, this exception will be raised."""44 def __init__(self, reason, now, claims):45 super(IdTokenError, self).__init__(46 "%s Current epoch = %s. The id_token was approximately: %s" % (47 reason, _epoch_to_local(now), json.dumps(dict(48 claims,49 iat=_epoch_to_local(claims["iat"]) if claims.get("iat") else None,50 exp=_epoch_to_local(claims["exp"]) if claims.get("exp") else None,51 ), indent=2)))52 53class _IdTokenTimeError(IdTokenError): # This is not intended to be raised and caught54 _SUGGESTION = "Make sure your computer's time and time zone are both correct."55 def __init__(self, reason, now, claims):56 super(_IdTokenTimeError, self).__init__(reason+ " " + self._SUGGESTION, now, claims)57 def log(self):58 # Influenced by JWT specs https://tools.ietf.org/html/rfc7519#section-4.1.559 # and OIDC specs https://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation60 # We used to raise this error, but now we just log it as warning, because:61 # 1. If it is caused by incorrect local machine time,62 # then the token(s) are still correct and probably functioning,63 # so, there is no point to error out.64 # 2. If it is caused by incorrect IdP time, then it is IdP's fault,65 # There is not much a client can do, so, we might as well return the token(s)66 # and let downstream components to decide what to do.67 logger.warning(str(self))68 69class IdTokenIssuerError(IdTokenError):70 pass71 72class IdTokenAudienceError(IdTokenError):73 pass74 75class IdTokenNonceError(IdTokenError):76 pass77 78def decode_id_token(id_token, client_id=None, issuer=None, nonce=None, now=None):79 """Decodes and validates an id_token and returns its claims as a dictionary.80 81 ID token claims would at least contain: "iss", "sub", "aud", "exp", "iat",82 per `specs <https://openid.net/specs/openid-connect-core-1_0.html#IDToken>`_83 and it may contain other optional content such as "preferred_username",84 `maybe more <https://openid.net/specs/openid-connect-core-1_0.html#Claims>`_85 """86 decoded = json.loads(decode_part(id_token.split('.')[1]))87 # Based on https://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation88 _now = int(now or time.time())89 skew = 120 # 2 minutes90 91 if _now + skew < decoded.get("nbf", _now - 1): # nbf is optional per JWT specs92 # This is not an ID token validation, but a JWT validation93 # https://tools.ietf.org/html/rfc7519#section-4.1.594 _IdTokenTimeError("0. The ID token is not yet valid.", _now, decoded).log()95 96 if issuer and issuer != decoded["iss"]:97 # https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationResponse98 raise IdTokenIssuerError(99 '2. The Issuer Identifier for the OpenID Provider, "%s", '100 "(which is typically obtained during Discovery), "101 "MUST exactly match the value of the iss (issuer) Claim." % issuer,102 _now,103 decoded)104 105 if client_id:106 valid_aud = client_id in decoded["aud"] if isinstance(107 decoded["aud"], list) else client_id == decoded["aud"]108 if not valid_aud:109 raise IdTokenAudienceError(110 "3. The aud (audience) claim must contain this client's client_id "111 '"%s", case-sensitively. Was your client_id in wrong casing?'112 # Some IdP accepts wrong casing request but issues right casing IDT113 % client_id,114 _now,115 decoded)116 117 # Per specs:118 # 6. If the ID Token is received via direct communication between119 # the Client and the Token Endpoint (which it is during _obtain_token()),120 # the TLS server validation MAY be used to validate the issuer121 # in place of checking the token signature.122 123 if _now - skew > decoded["exp"]:124 _IdTokenTimeError("9. The ID token already expires.", _now, decoded).log()125 126 if nonce and nonce != decoded.get("nonce"):127 raise IdTokenNonceError(128 "11. Nonce must be the same value "129 "as the one that was sent in the Authentication Request.",130 _now,131 decoded)132 133 return decoded134 135 136def _nonce_hash(nonce):137 # https://openid.net/specs/openid-connect-core-1_0.html#NonceNotes138 return hashlib.sha256(nonce.encode("ascii")).hexdigest()139 140 141class Prompt(object):142 """This class defines the constant strings for prompt parameter.143 144 The values are based on145 https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest146 """147 NONE = "none"148 LOGIN = "login"149 CONSENT = "consent"150 SELECT_ACCOUNT = "select_account"151 CREATE = "create" # Defined in https://openid.net/specs/openid-connect-prompt-create-1_0.html#PromptParameter152 153 154class Client(oauth2.Client):155 """OpenID Connect is a layer on top of the OAuth2.156 157 See its specs at https://openid.net/connect/158 """159 160 def decode_id_token(self, id_token, nonce=None):161 """See :func:`~decode_id_token`."""162 return decode_id_token(163 id_token, nonce=nonce,164 client_id=self.client_id, issuer=self.configuration.get("issuer"))165 166 def _obtain_token(self, grant_type, *args, **kwargs):167 """The result will also contain one more key "id_token_claims",168 whose value will be a dictionary returned by :func:`~decode_id_token`.169 """170 ret = super(Client, self)._obtain_token(grant_type, *args, **kwargs)171 if "id_token" in ret:172 ret["id_token_claims"] = self.decode_id_token(ret["id_token"])173 return ret174 175 def build_auth_request_uri(self, response_type, nonce=None, **kwargs):176 """Generate an authorization uri to be visited by resource owner.177 178 Return value and all other parameters are the same as179 :func:`oauth2.Client.build_auth_request_uri`, plus new parameter(s):180 181 :param nonce:182 A hard-to-guess string used to mitigate replay attacks. See also183 `OIDC specs <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.184 """185 warnings.warn("Use initiate_auth_code_flow() instead", DeprecationWarning)186 return super(Client, self).build_auth_request_uri(187 response_type, nonce=nonce, **kwargs)188 189 def obtain_token_by_authorization_code(self, code, nonce=None, **kwargs):190 """Get a token via authorization code. a.k.a. Authorization Code Grant.191 192 Return value and all other parameters are the same as193 :func:`oauth2.Client.obtain_token_by_authorization_code`,194 plus new parameter(s):195 196 :param nonce:197 If you provided a nonce when calling :func:`build_auth_request_uri`,198 same nonce should also be provided here, so that we'll validate it.199 An exception will be raised if the nonce in id token mismatches.200 """201 warnings.warn(202 "Use obtain_token_by_auth_code_flow() instead", DeprecationWarning)203 result = super(Client, self).obtain_token_by_authorization_code(204 code, **kwargs)205 nonce_in_id_token = result.get("id_token_claims", {}).get("nonce")206 if "id_token_claims" in result and nonce and nonce != nonce_in_id_token:207 raise ValueError(208 'The nonce in id token ("%s") should match your nonce ("%s")' %209 (nonce_in_id_token, nonce))210 return result211 212 def initiate_auth_code_flow(213 self,214 scope=None,215 **kwargs):216 """Initiate an auth code flow.217 218 It provides nonce protection automatically.219 220 :param list scope:221 A list of strings, e.g. ["profile", "email", ...].222 This method will automatically send ["openid"] to the wire,223 although it won't modify your input list.224 225 See :func:`oauth2.Client.initiate_auth_code_flow` in parent class226 for descriptions on other parameters and return value.227 """228 if "id_token" in kwargs.get("response_type", ""):229 # Implicit grant would cause auth response coming back in #fragment,230 # but fragment won't reach a web service.231 raise ValueError('response_type="id_token ..." is not allowed')232 _scope = list(scope) if scope else [] # We won't modify input parameter233 if "openid" not in _scope:234 # "If no openid scope value is present,235 # the request may still be a valid OAuth 2.0 request,236 # but is not an OpenID Connect request." -- OIDC Core Specs, 3.1.2.2237 # https://openid.net/specs/openid-connect-core-1_0.html#AuthRequestValidation238 # Here we just automatically add it. If the caller do not want id_token,239 # they should simply go with oauth2.Client.240 _scope.append("openid")241 nonce = "".join(random.sample(string.ascii_letters, 16))242 flow = super(Client, self).initiate_auth_code_flow(243 scope=_scope, nonce=_nonce_hash(nonce), **kwargs)244 flow["nonce"] = nonce245 if kwargs.get("max_age") is not None:246 flow["max_age"] = kwargs["max_age"]247 return flow248 249 def obtain_token_by_auth_code_flow(self, auth_code_flow, auth_response, **kwargs):250 """Validate the auth_response being redirected back, and then obtain tokens,251 including ID token which can be used for user sign in.252 253 Internally, it implements nonce to mitigate replay attack.254 It also implements PKCE to mitigate the auth code interception attack.255 256 See :func:`oauth2.Client.obtain_token_by_auth_code_flow` in parent class257 for descriptions on other parameters and return value.258 """259 result = super(Client, self).obtain_token_by_auth_code_flow(260 auth_code_flow, auth_response, **kwargs)261 if "id_token_claims" in result:262 nonce_in_id_token = result.get("id_token_claims", {}).get("nonce")263 expected_hash = _nonce_hash(auth_code_flow["nonce"])264 if nonce_in_id_token != expected_hash:265 raise RuntimeError(266 'The nonce in id token ("%s") should match our nonce ("%s")' %267 (nonce_in_id_token, expected_hash))268 269 if auth_code_flow.get("max_age") is not None:270 auth_time = result.get("id_token_claims", {}).get("auth_time")271 if not auth_time:272 raise RuntimeError(273 "13. max_age was requested, ID token should contain auth_time")274 now = int(time.time())275 skew = 120 # 2 minutes. Hardcoded, for now276 if now - skew > auth_time + auth_code_flow["max_age"]:277 raise RuntimeError(278 "13. auth_time ({auth_time}) was requested, "279 "by using max_age ({max_age}) parameter, "280 "and now ({now}) too much time has elasped "281 "since last end-user authentication. "282 "The ID token was: {id_token}".format(283 auth_time=auth_time,284 max_age=auth_code_flow["max_age"],285 now=now,286 id_token=json.dumps(result["id_token_claims"], indent=2),287 ))288 return result289 290 def obtain_token_by_browser(291 self,292 display=None,293 prompt=None,294 max_age=None,295 ui_locales=None,296 id_token_hint=None, # It is relevant,297 # because this library exposes raw ID token298 login_hint=None,299 acr_values=None,300 **kwargs):301 """A native app can use this method to obtain token via a local browser.302 303 Internally, it implements nonce to mitigate replay attack.304 It also implements PKCE to mitigate the auth code interception attack.305 306 :param string display: Defined in307 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.308 :param string prompt: Defined in309 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.310 You can find the valid string values defined in :class:`oidc.Prompt`.311 312 :param int max_age: Defined in313 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.314 :param string ui_locales: Defined in315 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.316 :param string id_token_hint: Defined in317 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.318 :param string login_hint: Defined in319 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.320 :param string acr_values: Defined in321 `OIDC <https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest>`_.322 323 See :func:`oauth2.Client.obtain_token_by_browser` in parent class324 for descriptions on other parameters and return value.325 """326 filtered_params = {k:v for k, v in dict(327 prompt=" ".join(prompt) if isinstance(prompt, (list, tuple)) else prompt,328 display=display,329 max_age=max_age,330 ui_locales=ui_locales,331 id_token_hint=id_token_hint,332 login_hint=login_hint,333 acr_values=acr_values,334 ).items() if v is not None} # Filter out None values335 return super(Client, self).obtain_token_by_browser(336 auth_params=dict(kwargs.pop("auth_params", {}), **filtered_params),337 **kwargs)338 339