osm_nbi/authconn_tacacs.py

   1 # -*- coding: utf-8 -*-
   2
   3 # Copyright 2020 TATA ELXSI
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   6 # not use this file except in compliance with the License. You may obtain
   7 # a copy of the License at
   8 #
   9 #         http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  13 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  14 # License for the specific language governing permissions and limitations
  15 # under the License.
  16 #
  17 # For those usages not covered by the Apache License, Version 2.0 please
  18 # contact: saikiran.k@tataelxsi.co.in
  19 ##
  20
  21
  22 """
  23 AuthconnTacacs implements implements the connector for TACACS.
  24 Leverages AuthconnInternal for token lifecycle management and the RBAC model.
  25
  26 When NBI bootstraps, it tries to create admin user with admin role associated to admin project.
  27 Hence, the TACACS server should contain admin user.
  28 """
  29
  30 __author__ = "K Sai Kiran <saikiran.k@tataelxsi.co.in>"
  31 __date__ = "$11-Nov-2020 11:04:00$"
  32
  33
  34 from osm_nbi.authconn import Authconn, AuthException
  35 from osm_nbi.authconn_internal import AuthconnInternal
  36 from osm_nbi.base_topic import BaseTopic
  37
  38 import logging
  39 from time import time
  40 from http import HTTPStatus
  41
  42 # TACACS+ Library
  43 from tacacs_plus.client import TACACSClient
  44
  45
  46 class AuthconnTacacs(AuthconnInternal):
  47     token_time_window = 2
  48     token_delay = 1
  49
  50     tacacs_def_port = 49
  51     tacacs_def_timeout = 10
  52     users_collection = "users_tacacs"
  53     roles_collection = "roles_tacacs"
  54     projects_collection = "projects_tacacs"
  55     tokens_collection = "tokens_tacacs"
  56
  57     def __init__(self, config, db, role_permissions):
  58         """
  59         Constructor to initialize db and TACACS server attributes to members.
  60         """
  61         Authconn.__init__(self, config, db, role_permissions)
  62         self.logger = logging.getLogger("nbi.authenticator.tacacs")
  63         self.db = db
  64         self.tacacs_host = config["tacacs_host"]
  65         self.tacacs_secret = config["tacacs_secret"]
  66         self.tacacs_port = config["tacacs_port"] if config.get("tacacs_port") else self.tacacs_def_port
  67         self.tacacs_timeout = config["tacacs_timeout"] if config.get("tacacs_timeout") else self.tacacs_def_timeout
  68         self.tacacs_cli = TACACSClient(self.tacacs_host, self.tacacs_port, self.tacacs_secret,
  69                                        self.tacacs_timeout)
  70
  71     def validate_user(self, user, password):
  72         """
  73         """
  74         now = time()
  75         try:
  76             tacacs_authen = self.tacacs_cli.authenticate(user, password)
  77         except Exception as e:
  78             raise AuthException("TACACS server error: {}".format(e), http_code=HTTPStatus.UNAUTHORIZED)
  79         user_content = None
  80         user_rows = self.db.get_list(self.users_collection, {BaseTopic.id_field("users", user): user})
  81         if not tacacs_authen.valid:
  82             if user_rows:
  83                 # To remove TACACS stale user from system.
  84                 self.delete_user(user_rows[0][BaseTopic.id_field("users", user)])
  85             return user_content
  86         if user_rows:
  87             user_content = user_rows[0]
  88         else:
  89             new_user = {'username': user,
  90                         'password': password,
  91                         '_admin': {
  92                             'created': now,
  93                             'modified': now
  94                         },
  95                         'project_role_mappings': []
  96                         }
  97             user_content = self.create_user(new_user)
  98         return user_content
  99
 100     def create_user(self, user_info):
 101         """
 102         Validates user credentials in TACACS and add user.
 103
 104         :param user_info: Full user information in dict.
 105         :return: returns username and id if credentails are valid. Otherwise, raise exception
 106         """
 107         BaseTopic.format_on_new(user_info, make_public=False)
 108         try:
 109             authen = self.tacacs_cli.authenticate(user_info["username"], user_info["password"])
 110             if authen.valid:
 111                 user_info.pop("password")
 112                 self.db.create(self.users_collection, user_info)
 113             else:
 114                 raise AuthException("TACACS server error: Invalid credentials", http_code=HTTPStatus.FORBIDDEN)
 115         except Exception as e:
 116             raise AuthException("TACACS server error: {}".format(e), http_code=HTTPStatus.BAD_REQUEST)
 117         return {"username": user_info["username"], "_id": user_info["_id"]}
 118
 119     def update_user(self, user_info):
 120         """
 121         Updates user information, in particular for add/remove of project and role mappings.
 122         Does not allow change of username or password.
 123
 124         :param user_info: Full user information in dict.
 125         :return: returns None for successful add/remove of project and role map.
 126         """
 127         if(user_info.get("username")):
 128             raise AuthException("Can not update username of this user", http_code=HTTPStatus.FORBIDDEN)
 129         if(user_info.get("password")):
 130             raise AuthException("Can not update password of this user", http_code=HTTPStatus.FORBIDDEN)
 131         super(AuthconnTacacs, self).update_user(user_info)