keycloak_openid.py

# -*- coding: utf-8 -*-
#
# The MIT License (MIT)
#
# Copyright (C) 2017 Marcos Pereira <marcospereira.mpj@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

"""Keycloak OpenID module.

The module contains mainly the implementation of KeycloakOpenID class, the main
class to handle authentication and token manipulation.
"""

import json
from typing import Optional

from jose import jwt

from .authorization import Authorization
from .connection import ConnectionManager
from .exceptions import (
    KeycloakAuthenticationError,
    KeycloakAuthorizationConfigError,
    KeycloakDeprecationError,
    KeycloakGetError,
    KeycloakInvalidTokenError,
    KeycloakPostError,
    KeycloakPutError,
    KeycloakRPTNotFound,
    raise_error_from_response,
)
from .uma_permissions import AuthStatus, build_permission_param
from .urls_patterns import (
    URL_AUTH,
    URL_CERTS,
    URL_CLIENT_REGISTRATION,
    URL_CLIENT_UPDATE,
    URL_DEVICE,
    URL_ENTITLEMENT,
    URL_INTROSPECT,
    URL_LOGOUT,
    URL_REALM,
    URL_TOKEN,
    URL_USERINFO,
    URL_WELL_KNOWN,
)


class KeycloakOpenID:
    """Keycloak OpenID client.

    :param server_url: Keycloak server url
    :param client_id: client id
    :param realm_name: realm name
    :param client_secret_key: client secret key
    :param verify: Boolean value to enable or disable certificate validation or a string
        containing a path to a CA bundle to use
    :param custom_headers: dict of custom header to pass to each HTML request
    :param proxies: dict of proxies to sent the request by.
    :param timeout: connection timeout in seconds
    """

    def __init__(
        self,
        server_url,
        realm_name,
        client_id,
        client_secret_key=None,
        verify=True,
        custom_headers=None,
        proxies=None,
        timeout=60,
    ):
        """Init method.

        :param server_url: Keycloak server url
        :type server_url: str
        :param client_id: client id
        :type client_id: str
        :param realm_name: realm name
        :type realm_name: str
        :param client_secret_key: client secret key
        :type client_secret_key: str
        :param verify: Boolean value to enable or disable certificate validation or a string
            containing a path to a CA bundle to use
        :type verify: Union[bool,str]
        :param custom_headers: dict of custom header to pass to each HTML request
        :type custom_headers: dict
        :param proxies: dict of proxies to sent the request by.
        :type proxies: dict
        :param timeout: connection timeout in seconds
        :type timeout: int
        """
        self.client_id = client_id
        self.client_secret_key = client_secret_key
        self.realm_name = realm_name
        headers = custom_headers if custom_headers is not None else dict()
        self.connection = ConnectionManager(
            base_url=server_url, headers=headers, timeout=timeout, verify=verify, proxies=proxies
        )

        self.authorization = Authorization()

    @property
    def client_id(self):
        """Get client id.

        :returns: Client id
        :rtype: str
        """
        return self._client_id

    @client_id.setter
    def client_id(self, value):
        self._client_id = value

    @property
    def client_secret_key(self):
        """Get the client secret key.

        :returns: Client secret key
        :rtype: str
        """
        return self._client_secret_key

    @client_secret_key.setter
    def client_secret_key(self, value):
        self._client_secret_key = value

    @property
    def realm_name(self):
        """Get the realm name.

        :returns: Realm name
        :rtype: str
        """
        return self._realm_name

    @realm_name.setter
    def realm_name(self, value):
        self._realm_name = value

    @property
    def connection(self):
        """Get connection.

        :returns: Connection manager object
        :rtype: ConnectionManager
        """
        return self._connection

    @connection.setter
    def connection(self, value):
        self._connection = value

    @property
    def authorization(self):
        """Get authorization.

        :returns: The authorization manager
        :rtype: Authorization
        """
        return self._authorization

    @authorization.setter
    def authorization(self, value):
        self._authorization = value

    def _add_secret_key(self, payload):
        """Add secret key if exists.

        :param payload: Payload
        :type payload: dict
        :returns: Payload with the secret key
        :rtype: dict
        """
        if self.client_secret_key:
            payload.update({"client_secret": self.client_secret_key})

        return payload

    def _build_name_role(self, role):
        """Build name of a role.

        :param role: Role name
        :type role: str
        :returns: Role path
        :rtype: str
        """
        return self.client_id + "/" + role

    def _token_info(self, token, method_token_info, **kwargs):
        """Getter for the token data.

        :param token: Token
        :type token: str
        :param method_token_info: Token info method to use
        :type method_token_info: str
        :param kwargs: Additional keyword arguments
        :type kwargs: dict
        :returns: Token info
        :rtype: dict
        """
        if method_token_info == "introspect":
            token_info = self.introspect(token)
        else:
            token_info = self.decode_token(token, **kwargs)

        return token_info

    def well_known(self):
        """Get the well_known object.

        The most important endpoint to understand is the well-known configuration
        endpoint. It lists endpoints and other configuration options relevant to
        the OpenID Connect implementation in Keycloak.

        :returns: It lists endpoints and other configuration options relevant
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        data_raw = self.connection.raw_get(URL_WELL_KNOWN.format(**params_path))
        return raise_error_from_response(data_raw, KeycloakGetError)

    def auth_url(self, redirect_uri, scope="email", state=""):
        """Get authorization URL endpoint.

        :param redirect_uri: Redirect url to receive oauth code
        :type redirect_uri: str
        :param scope: Scope of authorization request, split with the blank space
        :type scope: str
        :param state: State will be returned to the redirect_uri
        :type state: str
        :returns: Authorization URL Full Build
        :rtype: str
        """
        params_path = {
            "authorization-endpoint": self.well_known()["authorization_endpoint"],
            "client-id": self.client_id,
            "redirect-uri": redirect_uri,
            "scope": scope,
            "state": state,
        }
        return URL_AUTH.format(**params_path)

    def token(
        self,
        username="",
        password="",
        grant_type=["password"],
        code="",
        redirect_uri="",
        totp=None,
        scope="openid",
        **extra
    ):
        """Retrieve user token.

        The token endpoint is used to obtain tokens. Tokens can either be obtained by
        exchanging an authorization code or by supplying credentials directly depending on
        what flow is used. The token endpoint is also used to obtain new access tokens
        when they expire.

        http://openid.net/specs/openid-connect-core-1_0.html#TokenEndpoint

        :param username: Username
        :type username: str
        :param password: Password
        :type password: str
        :param grant_type: Grant type
        :type grant_type: str
        :param code: Code
        :type code: str
        :param redirect_uri: Redirect URI
        :type redirect_uri: str
        :param totp: Time-based one-time password
        :type totp: int
        :param scope: Scope, defaults to openid
        :type scope: str
        :param extra: Additional extra arguments
        :type extra: dict
        :returns: Keycloak token
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        payload = {
            "username": username,
            "password": password,
            "client_id": self.client_id,
            "grant_type": grant_type,
            "code": code,
            "redirect_uri": redirect_uri,
            "scope": scope,
        }
        if extra:
            payload.update(extra)

        if totp:
            payload["totp"] = totp

        payload = self._add_secret_key(payload)
        data_raw = self.connection.raw_post(URL_TOKEN.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def refresh_token(self, refresh_token, grant_type=["refresh_token"]):
        """Refresh the user token.

        The token endpoint is used to obtain tokens. Tokens can either be obtained by
        exchanging an authorization code or by supplying credentials directly depending on
        what flow is used. The token endpoint is also used to obtain new access tokens
        when they expire.

        http://openid.net/specs/openid-connect-core-1_0.html#TokenEndpoint

        :param refresh_token: Refresh token from Keycloak
        :type refresh_token: str
        :param grant_type: Grant type
        :type grant_type: str
        :returns: New token
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        payload = {
            "client_id": self.client_id,
            "grant_type": grant_type,
            "refresh_token": refresh_token,
        }
        payload = self._add_secret_key(payload)
        data_raw = self.connection.raw_post(URL_TOKEN.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def exchange_token(
        self,
        token: str,
        audience: Optional[str] = None,
        subject: Optional[str] = None,
        subject_token_type: Optional[str] = None,
        subject_issuer: Optional[str] = None,
        requested_issuer: Optional[str] = None,
        requested_token_type: str = "urn:ietf:params:oauth:token-type:refresh_token",
        scope: str = "openid",
    ) -> dict:
        """Exchange user token.

        Use a token to obtain an entirely different token. See
        https://www.keycloak.org/docs/latest/securing_apps/index.html#_token-exchange

        :param token: Access token
        :type token: str
        :param audience: Audience
        :type audience: str
        :param subject: Subject
        :type subject: str
        :param subject_token_type: Token Type specification
        :type subject_token_type: Optional[str]
        :param subject_issuer: Issuer
        :type subject_issuer: Optional[str]
        :param requested_issuer: Issuer
        :type requested_issuer: Optional[str]
        :param requested_token_type: Token type specification
        :type requested_token_type: str
        :param scope: Scope, defaults to openid
        :type scope: str
        :returns: Exchanged token
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        payload = {
            "grant_type": ["urn:ietf:params:oauth:grant-type:token-exchange"],
            "client_id": self.client_id,
            "subject_token": token,
            "subject_token_type": subject_token_type,
            "subject_issuer": subject_issuer,
            "requested_token_type": requested_token_type,
            "audience": audience,
            "requested_subject": subject,
            "requested_issuer": requested_issuer,
            "scope": scope,
        }
        payload = self._add_secret_key(payload)
        data_raw = self.connection.raw_post(URL_TOKEN.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def userinfo(self, token):
        """Get the user info object.

        The userinfo endpoint returns standard claims about the authenticated user,
        and is protected by a bearer token.

        http://openid.net/specs/openid-connect-core-1_0.html#UserInfo

        :param token: Access token
        :type token: str
        :returns: Userinfo object
        :rtype: dict
        """
        self.connection.add_param_headers("Authorization", "Bearer " + token)
        params_path = {"realm-name": self.realm_name}
        data_raw = self.connection.raw_get(URL_USERINFO.format(**params_path))
        return raise_error_from_response(data_raw, KeycloakGetError)

    def logout(self, refresh_token):
        """Log out the authenticated user.

        :param refresh_token: Refresh token from Keycloak
        :type refresh_token: str
        :returns: Keycloak server response
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        payload = {"client_id": self.client_id, "refresh_token": refresh_token}
        payload = self._add_secret_key(payload)
        data_raw = self.connection.raw_post(URL_LOGOUT.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError, expected_codes=[204])

    def certs(self):
        """Get certificates.

        The certificate endpoint returns the public keys enabled by the realm, encoded as a
        JSON Web Key (JWK). Depending on the realm settings there can be one or more keys enabled
        for verifying tokens.

        https://tools.ietf.org/html/rfc7517

        :returns: Certificates
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        data_raw = self.connection.raw_get(URL_CERTS.format(**params_path))
        return raise_error_from_response(data_raw, KeycloakGetError)

    def public_key(self):
        """Retrieve the public key.

        The public key is exposed by the realm page directly.

        :returns: The public key
        :rtype: str
        """
        params_path = {"realm-name": self.realm_name}
        data_raw = self.connection.raw_get(URL_REALM.format(**params_path))
        return raise_error_from_response(data_raw, KeycloakGetError)["public_key"]

    def entitlement(self, token, resource_server_id):
        """Get entitlements from the token.

        Client applications can use a specific endpoint to obtain a special security token
        called a requesting party token (RPT). This token consists of all the entitlements
        (or permissions) for a user as a result of the evaluation of the permissions and
        authorization policies associated with the resources being requested. With an RPT,
        client applications can gain access to protected resources at the resource server.

        :param token: Access token
        :type token: str
        :param resource_server_id: Resource server ID
        :type resource_server_id: str
        :returns: Entitlements
        :rtype: dict
        """
        self.connection.add_param_headers("Authorization", "Bearer " + token)
        params_path = {"realm-name": self.realm_name, "resource-server-id": resource_server_id}
        data_raw = self.connection.raw_get(URL_ENTITLEMENT.format(**params_path))

        if data_raw.status_code == 404 or data_raw.status_code == 405:
            return raise_error_from_response(data_raw, KeycloakDeprecationError)

        return raise_error_from_response(data_raw, KeycloakGetError)  # pragma: no cover

    def introspect(self, token, rpt=None, token_type_hint=None):
        """Introspect the user token.

        The introspection endpoint is used to retrieve the active state of a token.
        It is can only be invoked by confidential clients.

        https://tools.ietf.org/html/rfc7662

        :param token: Access token
        :type token: str
        :param rpt: Requesting party token
        :type rpt: str
        :param token_type_hint: Token type hint
        :type token_type_hint: str

        :returns: Token info
        :rtype: dict
        :raises KeycloakRPTNotFound: In case of RPT not specified
        """
        params_path = {"realm-name": self.realm_name}
        payload = {"client_id": self.client_id, "token": token}

        if token_type_hint == "requesting_party_token":
            if rpt:
                payload.update({"token": rpt, "token_type_hint": token_type_hint})
                self.connection.add_param_headers("Authorization", "Bearer " + token)
            else:
                raise KeycloakRPTNotFound("Can't found RPT.")

        payload = self._add_secret_key(payload)

        data_raw = self.connection.raw_post(URL_INTROSPECT.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def decode_token(self, token, key, algorithms=["RS256"], **kwargs):
        """Decode user token.

        A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) data
        structure that represents a cryptographic key.  This specification
        also defines a JWK Set JSON data structure that represents a set of
        JWKs.  Cryptographic algorithms and identifiers for use with this
        specification are described in the separate JSON Web Algorithms (JWA)
        specification and IANA registries established by that specification.

        https://tools.ietf.org/html/rfc7517

        :param token: Keycloak token
        :type token: str
        :param key: Decode key
        :type key: str
        :param algorithms: Algorithms to use for decoding
        :type algorithms: list[str]
        :param kwargs: Keyword arguments
        :type kwargs: dict
        :returns: Decoded token
        :rtype: dict
        """
        return jwt.decode(token, key, algorithms=algorithms, audience=self.client_id, **kwargs)

    def load_authorization_config(self, path):
        """Load Keycloak settings (authorization).

        :param path: settings file (json)
        :type path: str
        """
        with open(path, "r") as fp:
            authorization_json = json.load(fp)

        self.authorization.load_config(authorization_json)

    def get_policies(self, token, method_token_info="introspect", **kwargs):
        """Get policies by user token.

        :param token: User token
        :type token: str
        :param method_token_info: Method for token info decoding
        :type method_token_info: str
        :param kwargs: Additional keyword arguments
        :type kwargs: dict
        :return: Policies
        :rtype: dict
        :raises KeycloakAuthorizationConfigError: In case of bad authorization configuration
        :raises KeycloakInvalidTokenError: In case of bad token
        """
        if not self.authorization.policies:
            raise KeycloakAuthorizationConfigError(
                "Keycloak settings not found. Load Authorization Keycloak settings."
            )

        token_info = self._token_info(token, method_token_info, **kwargs)

        if method_token_info == "introspect" and not token_info["active"]:
            raise KeycloakInvalidTokenError("Token expired or invalid.")

        user_resources = token_info["resource_access"].get(self.client_id)

        if not user_resources:
            return None

        policies = []

        for policy_name, policy in self.authorization.policies.items():
            for role in user_resources["roles"]:
                if self._build_name_role(role) in policy.roles:
                    policies.append(policy)

        return list(set(policies))

    def get_permissions(self, token, method_token_info="introspect", **kwargs):
        """Get permission by user token.

        :param token: user token
        :type token: str
        :param method_token_info: Decode token method
        :type method_token_info: str
        :param kwargs: parameters for decode
        :type kwargs: dict
        :returns: permissions list
        :rtype: list
        :raises KeycloakAuthorizationConfigError: In case of bad authorization configuration
        :raises KeycloakInvalidTokenError: In case of bad token
        """
        if not self.authorization.policies:
            raise KeycloakAuthorizationConfigError(
                "Keycloak settings not found. Load Authorization Keycloak settings."
            )

        token_info = self._token_info(token, method_token_info, **kwargs)

        if method_token_info == "introspect" and not token_info["active"]:
            raise KeycloakInvalidTokenError("Token expired or invalid.")

        user_resources = token_info["resource_access"].get(self.client_id)

        if not user_resources:
            return None

        permissions = []

        for policy_name, policy in self.authorization.policies.items():
            for role in user_resources["roles"]:
                if self._build_name_role(role) in policy.roles:
                    permissions += policy.permissions

        return list(set(permissions))

    def uma_permissions(self, token, permissions=""):
        """Get UMA permissions by user token with requested permissions.

        The token endpoint is used to retrieve UMA permissions from Keycloak. It can only be
        invoked by confidential clients.

        http://openid.net/specs/openid-connect-core-1_0.html#TokenEndpoint

        :param token: user token
        :type token: str
        :param permissions: list of uma permissions list(resource:scope) requested by the user
        :type permissions: str
        :returns: Keycloak server response
        :rtype: dict
        """
        permission = build_permission_param(permissions)

        params_path = {"realm-name": self.realm_name}
        payload = {
            "grant_type": "urn:ietf:params:oauth:grant-type:uma-ticket",
            "permission": permission,
            "response_mode": "permissions",
            "audience": self.client_id,
        }

        self.connection.add_param_headers("Authorization", "Bearer " + token)
        data_raw = self.connection.raw_post(URL_TOKEN.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def has_uma_access(self, token, permissions):
        """Determine whether user has uma permissions with specified user token.

        :param token: user token
        :type token: str
        :param permissions: list of uma permissions (resource:scope)
        :type permissions: str
        :return: Authentication status
        :rtype: AuthStatus
        :raises KeycloakAuthenticationError: In case of failed authentication
        :raises KeycloakPostError: In case of failed request to Keycloak
        """
        needed = build_permission_param(permissions)
        try:
            granted = self.uma_permissions(token, permissions)
        except (KeycloakPostError, KeycloakAuthenticationError) as e:
            if e.response_code == 403:  # pragma: no cover
                return AuthStatus(
                    is_logged_in=True, is_authorized=False, missing_permissions=needed
                )
            elif e.response_code == 401:
                return AuthStatus(
                    is_logged_in=False, is_authorized=False, missing_permissions=needed
                )
            raise

        for resource_struct in granted:
            resource = resource_struct["rsname"]
            scopes = resource_struct.get("scopes", None)
            if not scopes:
                needed.discard(resource)
                continue
            for scope in scopes:  # pragma: no cover
                needed.discard("{}#{}".format(resource, scope))

        return AuthStatus(
            is_logged_in=True, is_authorized=len(needed) == 0, missing_permissions=needed
        )

    def register_client(self, token: str, payload: dict):
        """Create a client.

        ClientRepresentation:
        https://www.keycloak.org/docs-api/18.0/rest-api/index.html#_clientrepresentation

        :param token: Initial access token
        :type token: str
        :param payload: ClientRepresentation
        :type payload: dict
        :return: Client Representation
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        self.connection.add_param_headers("Authorization", "Bearer " + token)
        self.connection.add_param_headers("Content-Type", "application/json")
        data_raw = self.connection.raw_post(
            URL_CLIENT_REGISTRATION.format(**params_path), data=json.dumps(payload)
        )
        return raise_error_from_response(data_raw, KeycloakPostError)

    def device(self):
        """Get device authorization grant.

        The device endpoint is used to obtain a user code verification and user authentication.
        The response contains a device_code, user_code, verification_uri,
        verification_uri_complete, expires_in (lifetime in seconds for device_code
        and user_code), and polling interval.
        Users can either follow the verification_uri and enter the user_code or
        follow the verification_uri_complete.
        After authenticating with valid credentials, users can obtain tokens using the
        "urn:ietf:params:oauth:grant-type:device_code" grant_type and the device_code.

        https://auth0.com/docs/get-started/authentication-and-authorization-flow/device-authorization-flow
        https://github.com/keycloak/keycloak-community/blob/main/design/oauth2-device-authorization-grant.md#how-to-try-it

        :returns: Device Authorization Response
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name}
        payload = {"client_id": self.client_id}

        payload = self._add_secret_key(payload)
        data_raw = self.connection.raw_post(URL_DEVICE.format(**params_path), data=payload)
        return raise_error_from_response(data_raw, KeycloakPostError)

    def update_client(self, token: str, client_id: str, payload: dict):
        """Update a client.

        ClientRepresentation:
        https://www.keycloak.org/docs-api/18.0/rest-api/index.html#_clientrepresentation

        :param token: registration access token
        :type token: str
        :param client_id: Keycloak client id
        :type client_id: str
        :param payload: ClientRepresentation
        :type payload: dict
        :return: Client Representation
        :rtype: dict
        """
        params_path = {"realm-name": self.realm_name, "client-id": client_id}
        self.connection.add_param_headers("Authorization", "Bearer " + token)
        self.connection.add_param_headers("Content-Type", "application/json")

        # Keycloak complains if the clientId is not set in the payload
        if "clientId" not in payload:
            payload["clientId"] = client_id

        data_raw = self.connection.raw_put(
            URL_CLIENT_UPDATE.format(**params_path), data=json.dumps(payload)
        )
        return raise_error_from_response(data_raw, KeycloakPutError)