core/homeassistant/auth/mfa_modules/totp.py

236 lines
7.5 KiB
Python

"""Time-based One Time Password auth module."""
from __future__ import annotations
import asyncio
from io import BytesIO
from typing import Any, cast
import voluptuous as vol
from homeassistant.auth.models import User
from homeassistant.core import HomeAssistant
from homeassistant.data_entry_flow import FlowResult
from homeassistant.helpers.storage import Store
from . import (
MULTI_FACTOR_AUTH_MODULE_SCHEMA,
MULTI_FACTOR_AUTH_MODULES,
MultiFactorAuthModule,
SetupFlow,
)
REQUIREMENTS = ["pyotp==2.8.0", "PyQRCode==1.2.1"]
CONFIG_SCHEMA = MULTI_FACTOR_AUTH_MODULE_SCHEMA.extend({}, extra=vol.PREVENT_EXTRA)
STORAGE_VERSION = 1
STORAGE_KEY = "auth_module.totp"
STORAGE_USERS = "users"
STORAGE_USER_ID = "user_id"
STORAGE_OTA_SECRET = "ota_secret"
INPUT_FIELD_CODE = "code"
DUMMY_SECRET = "FPPTH34D4E3MI2HG"
def _generate_qr_code(data: str) -> str:
"""Generate a base64 PNG string represent QR Code image of data."""
import pyqrcode # pylint: disable=import-outside-toplevel
qr_code = pyqrcode.create(data)
with BytesIO() as buffer:
qr_code.svg(file=buffer, scale=4)
return str(
buffer.getvalue()
.decode("ascii")
.replace("\n", "")
.replace(
(
'<?xml version="1.0" encoding="UTF-8"?>'
'<svg xmlns="http://www.w3.org/2000/svg"'
),
"<svg",
)
)
def _generate_secret_and_qr_code(username: str) -> tuple[str, str, str]:
"""Generate a secret, url, and QR code."""
import pyotp # pylint: disable=import-outside-toplevel
ota_secret = pyotp.random_base32()
url = pyotp.totp.TOTP(ota_secret).provisioning_uri(
username, issuer_name="Home Assistant"
)
image = _generate_qr_code(url)
return ota_secret, url, image
@MULTI_FACTOR_AUTH_MODULES.register("totp")
class TotpAuthModule(MultiFactorAuthModule):
"""Auth module validate time-based one time password."""
DEFAULT_TITLE = "Time-based One Time Password"
MAX_RETRY_TIME = 5
def __init__(self, hass: HomeAssistant, config: dict[str, Any]) -> None:
"""Initialize the user data store."""
super().__init__(hass, config)
self._users: dict[str, str] | None = None
self._user_store = Store[dict[str, dict[str, str]]](
hass, STORAGE_VERSION, STORAGE_KEY, private=True, atomic_writes=True
)
self._init_lock = asyncio.Lock()
@property
def input_schema(self) -> vol.Schema:
"""Validate login flow input data."""
return vol.Schema({vol.Required(INPUT_FIELD_CODE): str})
async def _async_load(self) -> None:
"""Load stored data."""
async with self._init_lock:
if self._users is not None:
return
if (data := await self._user_store.async_load()) is None:
data = cast(dict[str, dict[str, str]], {STORAGE_USERS: {}})
self._users = data.get(STORAGE_USERS, {})
async def _async_save(self) -> None:
"""Save data."""
await self._user_store.async_save({STORAGE_USERS: self._users or {}})
def _add_ota_secret(self, user_id: str, secret: str | None = None) -> str:
"""Create a ota_secret for user."""
import pyotp # pylint: disable=import-outside-toplevel
ota_secret: str = secret or pyotp.random_base32()
self._users[user_id] = ota_secret # type: ignore[index]
return ota_secret
async def async_setup_flow(self, user_id: str) -> SetupFlow:
"""Return a data entry flow handler for setup module.
Mfa module should extend SetupFlow
"""
user = await self.hass.auth.async_get_user(user_id)
assert user is not None
return TotpSetupFlow(self, self.input_schema, user)
async def async_setup_user(self, user_id: str, setup_data: Any) -> str:
"""Set up auth module for user."""
if self._users is None:
await self._async_load()
result = await self.hass.async_add_executor_job(
self._add_ota_secret, user_id, setup_data.get("secret")
)
await self._async_save()
return result
async def async_depose_user(self, user_id: str) -> None:
"""Depose auth module for user."""
if self._users is None:
await self._async_load()
if self._users.pop(user_id, None): # type: ignore[union-attr]
await self._async_save()
async def async_is_user_setup(self, user_id: str) -> bool:
"""Return whether user is setup."""
if self._users is None:
await self._async_load()
return user_id in self._users # type: ignore[operator]
async def async_validate(self, user_id: str, user_input: dict[str, Any]) -> bool:
"""Return True if validation passed."""
if self._users is None:
await self._async_load()
# user_input has been validate in caller
# set INPUT_FIELD_CODE as vol.Required is not user friendly
return await self.hass.async_add_executor_job(
self._validate_2fa, user_id, user_input.get(INPUT_FIELD_CODE, "")
)
def _validate_2fa(self, user_id: str, code: str) -> bool:
"""Validate two factor authentication code."""
import pyotp # pylint: disable=import-outside-toplevel
if (ota_secret := self._users.get(user_id)) is None: # type: ignore[union-attr]
# even we cannot find user, we still do verify
# to make timing the same as if user was found.
pyotp.TOTP(DUMMY_SECRET).verify(code, valid_window=1)
return False
return bool(pyotp.TOTP(ota_secret).verify(code, valid_window=1))
class TotpSetupFlow(SetupFlow):
"""Handler for the setup flow."""
_auth_module: TotpAuthModule
_ota_secret: str
_url: str
_image: str
def __init__(
self, auth_module: TotpAuthModule, setup_schema: vol.Schema, user: User
) -> None:
"""Initialize the setup flow."""
super().__init__(auth_module, setup_schema, user.id)
self._user = user
async def async_step_init(
self, user_input: dict[str, str] | None = None
) -> FlowResult:
"""Handle the first step of setup flow.
Return self.async_show_form(step_id='init') if user_input is None.
Return self.async_create_entry(data={'result': result}) if finish.
"""
import pyotp # pylint: disable=import-outside-toplevel
errors: dict[str, str] = {}
if user_input:
verified = await self.hass.async_add_executor_job(
pyotp.TOTP(self._ota_secret).verify, user_input["code"]
)
if verified:
result = await self._auth_module.async_setup_user(
self._user_id, {"secret": self._ota_secret}
)
return self.async_create_entry(data={"result": result})
errors["base"] = "invalid_code"
else:
(
self._ota_secret,
self._url,
self._image,
) = await self._auth_module.hass.async_add_executor_job(
_generate_secret_and_qr_code,
str(self._user.name),
)
return self.async_show_form(
step_id="init",
data_schema=self._setup_schema,
description_placeholders={
"code": self._ota_secret,
"url": self._url,
"qr_code": self._image,
},
errors=errors,
)