_complete_webauthn_authentication -> _verify_webauthn_authentication
This function just does verification of the actual auth process -
checking the challenge is correct, the signature matches the public key
we have stored in our database, etc.
verify_webauthn_login -> _complete_webauthn_login_attempt
This function doesn't do any actual verification, we've already verified
the user is who they say they are (or not), it's about marking the
attempt, either unsuccessful (we bump the failed_login_count in the db)
or successful (we set the logged_in_at and current_session_id in the
db).
This change also informs changes to the names of methods on the user
model and in user_api_client.
flashes are consumed by the jinja template calling get_flashed_messages
in flash_messages.html.
When you call `abort(403)` the 403 error page is rendered, with the
flashed message on it. However, the webauthn endpoints just return that
page to the ajax `fetch`, which ignores the response and just reloads
the page.
Instead of calling abort, we can just return an empty response body and
the 403 error code, so that the flashed messages stay in the session and
will be rendered when the `GET /two-factor-webauthn` request happens
after the js reloads the page.
notably i had to change `window.location = foo` to
`window.location.assign` so that i could have something to spy on with
jest. mocking sucks. Otherwise this is pretty similar to the
registerSecurityKey.test.js file.
rather than having a gross if/else, we can define separately. This means
we can separate the asserts and test setups for the first fetch (get)
and the second fetch (post), which means we can arrange all the mocks in
the order they're called in the function, significantly enhancing
legibility of the tests
the js fetch function is really not designed to work with 302s. when it
receives a 302, it automatically follows it and fetches the next page.
This is awkward because I don't want js to do all this in ajax, I want
the browser to get the new URL so it can load the page.
A better approach is to view the admin endpoint as a more pure API: the
js sends a request for authentication to the admin app, and the admin
app responds with a 200 indicating success, and then a payload of
relevant data with that.
The relevant data in this case is "Which URL should I redirect to", it
might be the user's list of services page, or it might be a page telling
them that their email needs revalidating.
this doesn't include timeouts or other errors on the browser side - the
main thing this catches is if the token doesn't belong to the user.
However I'm not entirely clear if that's something that will be caught
at this point, or if the browser would reject that key as it's not in
the credentials passed in to the begin_authentication process.
the js `fetch` function will follow redirects blindly and return you the
final 200 response. when there's an error, we don't want to go anywhere,
and we want to use the flask `flash` functionality to pop up an error
page (the likely reason for seeing this is using a yubikey that isn't
associated with your user). using `flash` and then
`window.location.reload()` handles this fine.
However, when the user does log in succesfully we need to properly log
them in - this includes:
* checking their account isn't over the max login count
* resetting failed login count to 0 if not
* setting a new session id in the database (so other browser windows are
logged out)
* checking if they need to revalidate their email access (every 90 days)
* clearing old user out of the cache
This code all happens in the ajax function rather than being in a
separate redirect, so that you can't just navigate to the login flow. I
wasn't able to unit test that function due how it uses the session and
other flask globals, so moved the auth into its own function so it's
easy to stub out all that CBOR nonsense.
TODO: We still need to pass any `next` URLs through the chain from login
page all the way through the javascript AJAX calls and redirects to the
log_in_user function
this is a bit complex, but essentially we're using the test variables
defined in the duolabs py_webauthn library [1]. We're already using
their test variables in tests/app/models/test_webauthn_credential.py and
in the webauthn_credential fixture in conftest.py. By using sample
signature, authenticatordata and clientdatajson from the same key we can
test that the library correctly verifies the signed challenge matches
the original.
We needed to transform some of this data as the yubico/fido2 library we
use has a slightly different way of formatting the fields for the
request body, which is why we're doing things like base64 decoding and
converting from hex to bytes in the post data.
The pytest fixture has changed - before it was incomplete/corrupted and
would error when trying to verify the signature. We took the
credential_data from the pytest fixture, converted it to an
AttestedCredentialData using WebauthnCredential.to_credential_data,
modified the public_key private dictionary to add `public_key[-1]: 1`,
and then called `AttestedCredentialData.create` to re-CBOR-encode the
blob.
The `-1: 1` is the numeric ID of the "SECP256R1" elliptic curve
algorithm. The py_webauthn library forces this particular algorithm,
which differs from the sample creds we took from the fido2 lib tests,
which is why we've had to update our data.
[1] https://github.com/duo-labs/py_webauthn/blob/master/tests/test_webauthn.py#L13-L32
The flow of the code is roughly as follows:
user clicks button on webauthn page
js sends GET request
python reads GET request, sets up login challenge
python returns login challenge in response
js reads GET response, passes login challenge to browser
browser asks user to touch yubikey
browser returns yubikey challenge response data to js
js sends POST request with yubikey challenge response data
python reads yubikey challenge and compares with users creds from db
if its a match, python signs user in
The login challenge is a PublicKeyCredentialRequestOptions: [1]
The browser function we call is navigator.credentials.get(): [2]
The response to the challenge from the browser is a PublicKeyCredential: [3]
The python server does all the work setting those up and tearing them
back down again (and checking them against the values we have stored in
the database), but we need to do work to convert them to-and-from CBOR.
[1] https://developer.mozilla.org/en-US/docs/Web/API/PublicKeyCredentialRequestOptions
[2] https://developer.mozilla.org/en-US/docs/Web/API/CredentialsContainer/get
[3] https://developer.mozilla.org/en-US/docs/Web/API/PublicKeyCredential
if user has `webauthn_auth` as their auth type, then redirect them to an
interstitial that prompts them to click on a button which right now just
logs to the JS console, but in a future commit will open up the webauthn
browser prompt
content is unsurprisingly not final.
I don’t think we need to say (all networks) in the header. The real
benefit of this change is forcing the platform admin person making the
change to explicitly give their choice of network.
And by not putting it in the label we don’t have future users from other
organisations wondering if there’s some option other than ‘all networks’
they need to think about.
without the need for verification.
This is for when the email takes too long to arrive and the service
users cannot update it as a result.
A more streamlined solution has been proposed where we could send
a link in the verification email to the users and clicking that
link would add/update reply-email-to address.
That would require a bit more work so right now I am proposing this
as a quick stop gap so that we don't have to go to the database
manually to add the reply-to email address.
We can use the `optional_text_field` macro to grey out the text when
nothing is set up. And adding ‘registered’ makes the language consistent
through to the next page.
