import dataclasses import typing as t from datetime import datetime from functools import cached_property import nacl import nacl.encoding import nacl.hash import nacl.secret import nacl.signing from asgiref.sync import sync_to_async from django.conf import settings from django.contrib.auth import get_user_model, user_logged_out, user_logged_in from django.core import exceptions as django_exceptions from django.db import transaction from django.utils import timezone from fastapi import APIRouter, Depends, status, Request, Response from fastapi.security import APIKeyHeader from pydantic import BaseModel from django_etebase import app_settings, models from django_etebase.exceptions import EtebaseValidationError from django_etebase.models import UserInfo from django_etebase.signals import user_signed_up from django_etebase.token_auth.models import AuthToken from django_etebase.token_auth.models import get_default_expiry from django_etebase.utils import create_user, get_user_queryset, CallbackContext from django_etebase.views import msgpack_encode, msgpack_decode from .exceptions import AuthenticationFailed, transform_validation_error, ValidationError from .msgpack import MsgpackResponse, MsgpackRoute User = get_user_model() token_scheme = APIKeyHeader(name="Authorization") AUTO_REFRESH = True MIN_REFRESH_INTERVAL = 60 authentication_router = APIRouter(route_class=MsgpackRoute) @dataclasses.dataclass(frozen=True) class AuthData: user: User token: AuthToken class LoginChallengeIn(BaseModel): username: str class LoginChallengeOut(BaseModel): salt: bytes challenge: bytes version: int class LoginResponse(BaseModel): username: str challenge: bytes host: str action: t.Literal["login", "changePassword"] class UserOut(BaseModel): pubkey: bytes encryptedContent: bytes @classmethod def from_orm(cls: t.Type["UserOut"], obj: User) -> "UserOut": return cls(pubkey=obj.userinfo.pubkey, encryptedContent=obj.userinfo.encryptedContent) class LoginOut(BaseModel): token: str user: UserOut @classmethod def from_orm(cls: t.Type["LoginOut"], obj: User) -> "LoginOut": token = AuthToken.objects.create(user=obj).key user = UserOut.from_orm(obj) return cls(token=token, user=user) class Authentication(BaseModel): class Config: keep_untouched = (cached_property,) response: bytes signature: bytes class Login(Authentication): @cached_property def response_data(self) -> LoginResponse: return LoginResponse(**msgpack_decode(self.response)) class ChangePasswordResponse(LoginResponse): loginPubkey: bytes encryptedContent: bytes class ChangePassword(Authentication): @cached_property def response_data(self) -> ChangePasswordResponse: return ChangePasswordResponse(**msgpack_decode(self.response)) class UserSignup(BaseModel): username: str email: str class SignupIn(BaseModel): user: UserSignup salt: bytes loginPubkey: bytes pubkey: bytes encryptedContent: bytes def __renew_token(auth_token: AuthToken): current_expiry = auth_token.expiry new_expiry = get_default_expiry() # Throttle refreshing of token to avoid db writes delta = (new_expiry - current_expiry).total_seconds() if delta > MIN_REFRESH_INTERVAL: auth_token.expiry = new_expiry auth_token.save(update_fields=("expiry",)) @sync_to_async def __get_authenticated_user(api_token: str): api_token = api_token.split()[1] try: token: AuthToken = AuthToken.objects.select_related("user").get(key=api_token) except AuthToken.DoesNotExist: raise AuthenticationFailed(detail="Invalid token.") if not token.user.is_active: raise AuthenticationFailed(detail="User inactive or deleted.") if token.expiry is not None: if token.expiry < timezone.now(): token.delete() raise AuthenticationFailed(detail="Invalid token.") if AUTO_REFRESH: __renew_token(token) return token.user, token async def get_auth_data(api_token: str = Depends(token_scheme)) -> AuthData: user, token = await __get_authenticated_user(api_token) return AuthData(user, token) async def get_authenticated_user(api_token: str = Depends(token_scheme)) -> User: user, token = await __get_authenticated_user(api_token) return user @sync_to_async def __get_login_user(username: str) -> User: kwargs = {User.USERNAME_FIELD + "__iexact": username.lower()} try: user = User.objects.get(**kwargs) if not hasattr(user, "userinfo"): raise AuthenticationFailed(code="user_not_init", detail="User not properly init") return user except User.DoesNotExist: raise AuthenticationFailed(code="user_not_found", detail="User not found") async def get_login_user(challenge: LoginChallengeIn) -> User: user = await __get_login_user(challenge.username) return user def get_encryption_key(salt): key = nacl.hash.blake2b(settings.SECRET_KEY.encode(), encoder=nacl.encoding.RawEncoder) return nacl.hash.blake2b( b"", key=key, salt=salt[: nacl.hash.BLAKE2B_SALTBYTES], person=b"etebase-auth", encoder=nacl.encoding.RawEncoder, ) def save_changed_password(data: ChangePassword, user: User): response_data = data.response_data user_info: UserInfo = user.userinfo user_info.loginPubkey = response_data.loginPubkey user_info.encryptedContent = response_data.encryptedContent user_info.save() @sync_to_async def validate_login_request( validated_data: LoginResponse, challenge_sent_to_user: Authentication, user: User, expected_action: str, host_from_request: str, ): enc_key = get_encryption_key(bytes(user.userinfo.salt)) box = nacl.secret.SecretBox(enc_key) challenge_data = msgpack_decode(box.decrypt(validated_data.challenge)) now = int(datetime.now().timestamp()) if validated_data.action != expected_action: raise ValidationError("wrong_action", f'Expected "{challenge_sent_to_user.response}" but got something else') elif now - challenge_data["timestamp"] > app_settings.CHALLENGE_VALID_SECONDS: raise ValidationError("challenge_expired", "Login challenge has expired") elif challenge_data["userId"] != user.id: raise ValidationError("wrong_user", "This challenge is for the wrong user") elif not settings.DEBUG and validated_data.host.split(":", 1)[0] != host_from_request: raise ValidationError( "wrong_host", f'Found wrong host name. Got: "{validated_data.host}" expected: "{host_from_request}"' ) verify_key = nacl.signing.VerifyKey(bytes(user.userinfo.loginPubkey), encoder=nacl.encoding.RawEncoder) try: verify_key.verify(challenge_sent_to_user.response, challenge_sent_to_user.signature) except nacl.exceptions.BadSignatureError: raise ValidationError("login_bad_signature", "Wrong password for user.", status.HTTP_401_UNAUTHORIZED) @authentication_router.get("/is_etebase/") async def is_etebase(): return MsgpackResponse({}) @authentication_router.post("/login_challenge/") async def login_challenge(user: User = Depends(get_login_user)): enc_key = get_encryption_key(user.userinfo.salt) box = nacl.secret.SecretBox(enc_key) challenge_data = { "timestamp": int(datetime.now().timestamp()), "userId": user.id, } challenge = bytes(box.encrypt(msgpack_encode(challenge_data), encoder=nacl.encoding.RawEncoder)) return MsgpackResponse( LoginChallengeOut(salt=user.userinfo.salt, challenge=challenge, version=user.userinfo.version) ) @authentication_router.post("/login/") async def login(data: Login, request: Request): user = await get_login_user(LoginChallengeIn(username=data.response_data.username)) host = request.headers.get("Host") await validate_login_request(data.response_data, data, user, "login", host) data = await sync_to_async(LoginOut.from_orm)(user) await sync_to_async(user_logged_in.send)(sender=user.__class__, request=None, user=user) return MsgpackResponse(content=data, status_code=status.HTTP_200_OK) @authentication_router.post("/logout/") async def logout(request: Request, auth_data: AuthData = Depends(get_auth_data)): await sync_to_async(auth_data.token.delete)() # XXX-TOM await sync_to_async(user_logged_out.send)(sender=auth_data.user.__class__, request=None, user=auth_data.user) return Response(status_code=status.HTTP_204_NO_CONTENT) @authentication_router.post("/change_password/") async def change_password(data: ChangePassword, request: Request, user: User = Depends(get_authenticated_user)): host = request.headers.get("Host") await validate_login_request(data.response_data, data, user, "changePassword", host) await sync_to_async(save_changed_password)(data, user) return Response(status_code=status.HTTP_204_NO_CONTENT) def signup_save(data: SignupIn, request: Request) -> User: user_data = data.user with transaction.atomic(): try: user_queryset = get_user_queryset(User.objects.all(), CallbackContext(request.path_params)) instance = user_queryset.get(**{User.USERNAME_FIELD: user_data.username.lower()}) except User.DoesNotExist: # Create the user and save the casing the user chose as the first name try: instance = create_user( **user_data.dict(), password=None, first_name=user_data.username, context=CallbackContext(request.path_params), ) instance.full_clean() except EtebaseValidationError as e: raise e except django_exceptions.ValidationError as e: transform_validation_error("user", e) except Exception as e: raise EtebaseValidationError("generic", str(e)) if hasattr(instance, "userinfo"): raise ValidationError("user_exists", "User already exists", status_code=status.HTTP_409_CONFLICT) models.UserInfo.objects.create(**data.dict(exclude={"user"}), owner=instance) return instance @authentication_router.post("/signup/") async def signup(data: SignupIn, request: Request): user = await sync_to_async(signup_save)(data, request) # XXX-TOM data = await sync_to_async(LoginOut.from_orm)(user) await sync_to_async(user_signed_up.send)(sender=user.__class__, request=None, user=user) return MsgpackResponse(content=data, status_code=status.HTTP_201_CREATED)