71 lines
3.2 KiB
Python
71 lines
3.2 KiB
Python
"""This module is used to control authentication/authorization of Kobo sync requests.
|
|
This module also includes research notes into the auth protocol used by Kobo devices.
|
|
|
|
Log-in:
|
|
When first booting a Kobo device the user must sign into a Kobo (or affiliate) account.
|
|
Upon successful sign-in, the user is redirected to
|
|
https://auth.kobobooks.com/CrossDomainSignIn?id=<some id>
|
|
which serves the following response:
|
|
<script type='text/javascript'>location.href='kobo://UserAuthenticated?userId=<redacted>&userKey<redacted>&email=<redacted>&returnUrl=https%3a%2f%2fwww.kobo.com';</script>.
|
|
And triggers the insertion of a userKey into the device's User table.
|
|
|
|
IMPORTANT SECURITY CAUTION:
|
|
Together, the device's DeviceId and UserKey act as an *irrevocable* authentication
|
|
token to most (if not all) Kobo APIs. In fact, in most cases only the UserKey is
|
|
required to authorize the API call.
|
|
|
|
Changing Kobo password *does not* invalidate user keys! This is apparently a known
|
|
issue for a few years now https://www.mobileread.com/forums/showpost.php?p=3476851&postcount=13
|
|
(although this poster hypothesised that Kobo could blacklist a DeviceId, many endpoints
|
|
will still grant access given the userkey.)
|
|
|
|
Api authorization:
|
|
* For most of the endpoints we care about (sync, metadata, tags, etc), the userKey is
|
|
passed in the x-kobo-userkey header, and is sufficient to authorize the API call.
|
|
* Some endpoints (e.g: AnnotationService) instead make use of Bearer tokens. To get a
|
|
BearerToken, the device makes a POST request to the v1/auth/device endpoint with the
|
|
secret UserKey and the device's DeviceId.
|
|
|
|
Our implementation:
|
|
For now, we rely on the official Kobo store's UserKey for authentication. Because of the
|
|
irrevocable power granted by the key, we only ever store and compare a hash of the key.
|
|
To obtain their UserKey, a user can query the user table from the
|
|
.kobo/KoboReader.sqlite database found on their device.
|
|
This isn't exactly user friendly however.
|
|
|
|
Some possible alternatives that require more research:
|
|
* Instead of having users query the device database to find out their UserKey, we could
|
|
provide a list of recent Kobo sync attempts in the calibre-web UI for users to
|
|
authenticate sync attempts (e.g: 'this was me' button).
|
|
* We may be able to craft a sign-in flow with a redirect back to the CalibreWeb
|
|
server containing the KoboStore's UserKey.
|
|
* Can we create our own UserKey instead of relying on the real store's userkey?
|
|
(Maybe using something like location.href=kobo://UserAuthenticated?userId=...?)
|
|
"""
|
|
|
|
from functools import wraps
|
|
from flask import request, make_response
|
|
from werkzeug.security import check_password_hash
|
|
|
|
from . import logger, ub, lm
|
|
|
|
USER_KEY_HEADER = "x-kobo-userkey"
|
|
log = logger.create()
|
|
|
|
|
|
def disable_failed_auth_redirect_for_blueprint(bp):
|
|
lm.blueprint_login_views[bp.name] = None
|
|
|
|
|
|
@lm.request_loader
|
|
def load_user_from_kobo_request(request):
|
|
user_key = request.headers.get(USER_KEY_HEADER)
|
|
if user_key:
|
|
for user in (
|
|
ub.session.query(ub.User).filter(ub.User.kobo_user_key_hash != "").all()
|
|
):
|
|
if check_password_hash(str(user.kobo_user_key_hash), user_key):
|
|
return user
|
|
log.info("Received Kobo request without a recognizable UserKey.")
|
|
return None
|