Previously, if the sso= payload was invalid Base64, but signed correctly, there would be no useful log or error. This commit improves things by:
- moving the base64 check before the signature checking so that it's properly surfaced
- split the ParseError exception into PayloadParseError and SignatureError
- add user-facing errors for both of those
- add/improve spec for both
This commit adds support for an optional `prompt` parameter in the
payload of the /session/sso_provider endpoint. If an SSO Consumer
adds a `prompt=none` parameter to the encoded/signed `sso` payload,
then Discourse will avoid trying to login a not-logged-in user:
* If the user is already logged in, Discourse will immediately
redirect back to the Consumer with the user's credentials in a
signed payload, as usual.
* If the user is not logged in, Discourse will immediately redirect
back to the Consumer with a signed payload bearing the parameter
`failed=true`.
This allows the SSO Consumer to simply test whether or not a user is
logged in, without forcing the user to try to log in. This is useful
when the SSO Consumer allows both anonymous and authenticated access.
(E.g., users that are already logged-in to Discourse can be seamlessly
logged-in to the Consumer site, and anonymous users can remain
anonymous until they explicitly ask to log in.)
This feature is similar to the `prompt=none` functionality in an
OpenID Connect Authentication Request; see
https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
Previously we limited Discourse Connect provider to 1 secret per domain.
This made it pretty awkward to cycle secrets in environments where config
takes time to propagate
This change allows for the same domain to have multiple secrets
Also fixes internal implementation on DiscourseConnectProvider which was
not thread safe as it leaned on class variables to ferry data around
Co-authored-by: Alan Guo Xiang Tan <gxtan1990@gmail.com>
Co-authored-by: David Taylor <david@taylorhq.com>
Discourse has the Discourse Connect Provider protocol that makes it possible to
use a Discourse instance as an identity provider for external sites. As a
natural extension to this protocol, this PR adds a new feature that makes it
possible to use Discourse as a 2FA provider as well as an identity provider.
The rationale for this change is that it's very difficult to implement 2FA
support in a website and if you have multiple websites that need to have 2FA,
it's unrealistic to build and maintain a separate 2FA implementation for each
one. But with this change, you can piggyback on Discourse to take care of all
the 2FA details for you for as many sites as you wish.
To use Discourse as a 2FA provider, you'll need to follow this guide:
https://meta.discourse.org/t/-/32974. It walks you through what you need to
implement on your end/site and how to configure your Discourse instance. Once
you're done, there is only one additional thing you need to do which is to
include `require_2fa=true` in the payload that you send to Discourse.
When Discourse sees `require_2fa=true`, it'll prompt the user to confirm their
2FA using whatever methods they've enabled (TOTP or security keys), and once
they confirm they'll be redirected back to the return URL you've configured and
the payload will contain `confirmed_2fa=true`. If the user has no 2FA methods
enabled however, the payload will not contain `confirmed_2fa`, but it will
contain `no_2fa_methods=true`.
You'll need to be careful to re-run all the security checks and ensure the user
can still access the resource on your site after they return from Discourse.
This is very important because there's nothing that guarantees the user that
will come back from Discourse after they confirm 2FA is the same user that
you've redirected to Discourse.
Internal ticket: t62183.
David Taylor
Matt Marjanović
Daniel Waterworth
Sam
Osama Sayegh
Andrei Prigorshnev