285 lines
11 KiB
Python
285 lines
11 KiB
Python
# The Flask HTTP Digest Authentication Project.
|
|
# Author: imacat@mail.imacat.idv.tw (imacat), 2022/10/22
|
|
|
|
# Copyright (c) 2022 imacat.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""The HTTP Digest Authentication.
|
|
See RFC 2617 HTTP Authentication: Basic and Digest Access Authentication
|
|
|
|
"""
|
|
from __future__ import annotations
|
|
|
|
import sys
|
|
import typing as t
|
|
from functools import wraps
|
|
from random import random
|
|
from secrets import token_urlsafe
|
|
|
|
from flask import g, request, Response, session, abort, Flask, Request, \
|
|
current_app
|
|
from itsdangerous import URLSafeTimedSerializer, BadData
|
|
from werkzeug.datastructures import Authorization
|
|
|
|
from flask_digest_auth.algo import calc_response
|
|
from flask_digest_auth.exception import UnauthorizedException
|
|
|
|
|
|
class DigestAuth:
|
|
"""The HTTP digest authentication."""
|
|
|
|
def __init__(self, realm: t.Optional[str] = None):
|
|
"""Constructs the HTTP digest authentication.
|
|
|
|
:param realm: The realm.
|
|
"""
|
|
self.secret_key: str = token_urlsafe(32)
|
|
self.serializer: URLSafeTimedSerializer \
|
|
= URLSafeTimedSerializer(self.secret_key)
|
|
self.realm: str = "" if realm is None else realm
|
|
self.algorithm: t.Optional[str] = None
|
|
self.use_opaque: bool = True
|
|
self.domain: t.List[str] = []
|
|
self.qop: t.List[str] = ["auth", "auth-int"]
|
|
self.__get_password_hash: t.Callable[[str], t.Optional[str]] \
|
|
= lambda x: None
|
|
self.__get_user: t.Callable[[str], t.Optional] = lambda x: None
|
|
|
|
def login_required(self, view) -> t.Callable:
|
|
"""The view decorator for HTTP digest authentication.
|
|
|
|
:param view:
|
|
:return: The login-protected view.
|
|
"""
|
|
|
|
class NoLogInException(Exception):
|
|
"""The exception thrown when the user is not authorized."""
|
|
|
|
@wraps(view)
|
|
def login_required_view(*args, **kwargs) -> t.Any:
|
|
"""The login-protected view.
|
|
|
|
:param args: The positional arguments of the view.
|
|
:param kwargs: The keyword arguments of the view.
|
|
:return: The response.
|
|
"""
|
|
try:
|
|
if "user" not in session:
|
|
raise NoLogInException
|
|
user: t.Optional[t.Any] = self.__get_user(session["user"])
|
|
if user is None:
|
|
raise NoLogInException
|
|
g.user = user
|
|
return view(*args, **kwargs)
|
|
except NoLogInException:
|
|
state: AuthState = AuthState()
|
|
authorization: Authorization = request.authorization
|
|
try:
|
|
if authorization is None:
|
|
raise UnauthorizedException
|
|
if authorization.type != "digest":
|
|
raise UnauthorizedException(
|
|
"Not an HTTP digest authorization")
|
|
self.authenticate(state)
|
|
session["user"] = authorization.username
|
|
g.user = self.__get_user(authorization.username)
|
|
return view(*args, **kwargs)
|
|
except UnauthorizedException as e:
|
|
if len(e.args) > 0:
|
|
sys.stderr.write(e.args[0] + "\n")
|
|
response: Response = Response()
|
|
response.status = 401
|
|
response.headers["WWW-Authenticate"] \
|
|
= self.make_response_header(state)
|
|
abort(response)
|
|
|
|
return login_required_view
|
|
|
|
def authenticate(self, state: AuthState) -> None:
|
|
"""Authenticate a user.
|
|
|
|
:param state: The authorization state.
|
|
:return: None.
|
|
:raise UnauthorizedException: When the authentication failed.
|
|
"""
|
|
if "digest_auth_logout" in session:
|
|
del session["digest_auth_logout"]
|
|
raise UnauthorizedException("Logging out")
|
|
authorization: Authorization = request.authorization
|
|
if self.use_opaque:
|
|
if authorization.opaque is None:
|
|
raise UnauthorizedException(
|
|
"Missing \"opaque\" in the Authorization header")
|
|
try:
|
|
self.serializer.loads(
|
|
authorization.opaque, salt="opaque", max_age=1800)
|
|
except BadData:
|
|
raise UnauthorizedException("Invalid opaque")
|
|
state.opaque = authorization.opaque
|
|
password_hash: t.Optional[str] = self.__get_password_hash(
|
|
authorization.username)
|
|
if password_hash is None:
|
|
raise UnauthorizedException(
|
|
f"No such user \"{authorization.username}\"")
|
|
expected: str = calc_response(
|
|
method=request.method, uri=authorization.uri,
|
|
password_hash=password_hash, nonce=authorization.nonce,
|
|
qop=authorization.qop,
|
|
algorithm=authorization.get("algorithm"),
|
|
cnonce=authorization.cnonce, nc=authorization.nc,
|
|
body=request.data)
|
|
if authorization.response != expected:
|
|
state.stale = False
|
|
raise UnauthorizedException("Incorrect response value")
|
|
try:
|
|
self.serializer.loads(
|
|
authorization.nonce,
|
|
salt="nonce" if authorization.opaque is None
|
|
else f"nonce-{authorization.opaque}")
|
|
except BadData:
|
|
state.stale = True
|
|
raise UnauthorizedException("Invalid nonce")
|
|
|
|
def make_response_header(self, state: AuthState) -> str:
|
|
"""Composes and returns the WWW-Authenticate response header.
|
|
|
|
:param state: The authorization state.
|
|
:return: The WWW-Authenticate response header.
|
|
"""
|
|
opaque: t.Optional[str] = None if not self.use_opaque else \
|
|
(state.opaque if state.opaque is not None
|
|
else self.serializer.dumps(random(), salt="opaque"))
|
|
nonce: str = self.serializer.dumps(
|
|
random(), salt="nonce" if opaque is None else f"nonce-{opaque}")
|
|
|
|
header: str = f"Digest realm=\"{self.realm}\""
|
|
if len(self.domain) > 0:
|
|
domain_list: str = ",".join(self.domain)
|
|
header += f", domain=\"{domain_list}\""
|
|
header += f", nonce=\"{nonce}\""
|
|
if opaque is not None:
|
|
header += f", opaque=\"{opaque}\""
|
|
if state.stale is not None:
|
|
header += f", stale=TRUE" if state.stale else f", stale=FALSE"
|
|
if self.algorithm is not None:
|
|
header += f", algorithm=\"{self.algorithm}\""
|
|
if len(self.qop) > 0:
|
|
qop_list: str = ",".join(self.qop)
|
|
header += f", qop=\"{qop_list}\""
|
|
return header
|
|
|
|
def register_get_password(self, func: t.Callable[[str], t.Optional[str]])\
|
|
-> None:
|
|
"""Registers the callback to obtain the password hash.
|
|
|
|
:param func: The callback that given the username, returns the password
|
|
hash, or None if the user does not exist.
|
|
:return: None.
|
|
"""
|
|
self.__get_password_hash = func
|
|
|
|
def register_get_user(self, func: t.Callable[[str], t.Optional[t.Any]])\
|
|
-> None:
|
|
"""Registers the callback to obtain the user.
|
|
|
|
:param func: The callback that given the username, returns the user,
|
|
or None if the user does not exist.
|
|
:return: None.
|
|
"""
|
|
self.__get_user = func
|
|
|
|
def init_app(self, app: Flask) -> None:
|
|
"""Initializes the Flask application.
|
|
|
|
:param app: The Flask application.
|
|
:return: None.
|
|
"""
|
|
|
|
try:
|
|
from flask_login import LoginManager, login_user
|
|
|
|
if not hasattr(app, "login_manager"):
|
|
raise AttributeError(
|
|
"Please run the Flask-Login init-app() first")
|
|
login_manager: LoginManager = getattr(app, "login_manager")
|
|
|
|
@login_manager.unauthorized_handler
|
|
def unauthorized() -> None:
|
|
"""Handles when the user is unauthorized.
|
|
|
|
:return: None.
|
|
"""
|
|
response: Response = Response()
|
|
response.status = 401
|
|
response.headers["WWW-Authenticate"] \
|
|
= self.make_response_header(g.digest_auth_state)
|
|
abort(response)
|
|
|
|
@login_manager.request_loader
|
|
def load_user_from_request(req: Request) -> t.Optional[t.Any]:
|
|
"""Loads the user from the request header.
|
|
|
|
:param req: The request.
|
|
:return: The authenticated user, or None if the
|
|
authentication fails
|
|
"""
|
|
g.digest_auth_state = AuthState()
|
|
authorization: Authorization = req.authorization
|
|
try:
|
|
if authorization is None:
|
|
raise UnauthorizedException
|
|
if authorization.type != "digest":
|
|
raise UnauthorizedException(
|
|
"Not an HTTP digest authorization")
|
|
self.authenticate(g.digest_auth_state)
|
|
user = login_manager.user_callback(
|
|
authorization.username)
|
|
login_user(user)
|
|
return user
|
|
except UnauthorizedException as e:
|
|
if str(e) != "":
|
|
app.logger.warning(str(e))
|
|
return None
|
|
|
|
except ModuleNotFoundError:
|
|
raise ModuleNotFoundError(
|
|
"init_app() is only for Flask-Login integration")
|
|
|
|
@staticmethod
|
|
def logout() -> None:
|
|
"""Logs out the user.
|
|
This actually causes the next authentication to fail, which forces
|
|
the browser to ask the user for the username and password again.
|
|
|
|
:return: None.
|
|
"""
|
|
if "user" in session:
|
|
del session["user"]
|
|
try:
|
|
if hasattr(current_app, "login_manager"):
|
|
from flask_login import logout_user
|
|
logout_user()
|
|
except ModuleNotFoundError:
|
|
pass
|
|
session["digest_auth_logout"] = True
|
|
|
|
|
|
class AuthState:
|
|
"""The authorization state."""
|
|
|
|
def __init__(self):
|
|
"""Constructs the authorization state."""
|
|
self.opaque: t.Optional[str] = None
|
|
self.stale: t.Optional[bool] = None
|