Context, Fixes: https://github.com/matrix-org/synapse/issues/9263
In the past to fix an issue with old Riots re-requesting threepid validation tokens, we raised a `LoginError` during UIA instead of `InteractiveAuthIncompleteError`. This is now breaking the way Tchap logs in - which isn't standard, but also isn't disallowed by the spec.
An easy fix is just to remove the 4 year old workaround.
There's some prelimiary work here to pull out the construction of a jinja environment to a separate function.
I wanted to load the template at display time rather than load time, so that it's easy to update on the fly. Honestly, I think we should do this with all our templates: the risk of ending up with malformed templates is far outweighed by the improved turnaround time for an admin trying to update them.
There are going to be a couple of paths to get to the final step of SSO reg, and I want the URL in the browser to consistent. So, let's move the final step onto a separate path, which we redirect to.
We've decided to add a 'brand' field to help clients decide how to style the
buttons.
Also, fix up the allowed characters for idp_id, while I'm in the area.
* Factor out a common TestHtmlParser
Looks like I'm doing this in a few different places.
* Improve OIDC login test
Complete the OIDC login flow, rather than giving up halfway through.
* Ensure that OIDC login works with multiple OIDC providers
* Fix bugs in handling clientRedirectUrl
- don't drop duplicate query-params, or params with no value
- allow utf-8 in query-params
This is the final step for supporting multiple OIDC providers concurrently.
First of all, we reorganise the config so that you can specify a list of OIDC providers, instead of a single one. Before:
oidc_config:
enabled: true
issuer: "https://oidc_provider"
# etc
After:
oidc_providers:
- idp_id: prov1
issuer: "https://oidc_provider"
- idp_id: prov2
issuer: "https://another_oidc_provider"
The old format is still grandfathered in.
With that done, it's then simply a matter of having OidcHandler instantiate a new OidcProvider for each configured provider.
Again in preparation for handling more than one OIDC provider, add a new caveat to the macaroon used as an OIDC session cookie, which remembers which OIDC provider we are talking to. In future, when we get a callback, we'll need it to make sure we talk to the right IdP.
As part of this, I'm adding an idp_id and idp_name field to the OIDC configuration object. They aren't yet documented, and we'll just use the old values by default.
The idea here is that we will have an instance of OidcProvider for each
configured IdP, with OidcHandler just doing the marshalling of them.
For now it's still hardcoded with a single provider.
If a user tries to do UI Auth via SSO, but uses the wrong account on the SSO
IdP, try to give them a better error.
Previously, the UIA would claim to be successful, but then the operation in
question would simply fail with "auth fail". Instead, serve up an error page
which explains the failure.
Some light refactoring of OidcHandler, in preparation for bigger things:
* remove inheritance from deprecated BaseHandler
* add an object to hold the things that go into a session cookie
* factor out a separate class for manipulating said cookies
If we have integrations with multiple identity providers, when the user does a UI Auth, we need to redirect them to the right one.
There are a few steps to this. First of all we actually need to store the userid of the user we are trying to validate in the UIA session, since the /auth/sso/fallback/web request is unauthenticated.
Then, once we get the /auth/sso/fallback/web request, we can fish the user id out of the session, and use it to look up the external id mappings, and hence pick an SSO provider for them.
SynapseRequest is in danger of becoming a bit of a dumping-ground for "useful stuff relating to Requests",
which isn't really its intention (its purpose is to override render, finished and connectionLost to set up the
LoggingContext and write the right entries to the request log).
Putting utility functions inside SynapseRequest means that lots of our code ends up requiring a
SynapseRequest when there is nothing synapse-specific about the Request at all, and any old
twisted.web.iweb.IRequest will do. This increases code coupling and makes testing more difficult.
In short: move get_user_agent out to a utility function.
* Implement CasHandler.handle_redirect_request
... to make it match OidcHandler and SamlHandler
* Clean up interface for OidcHandler.handle_redirect_request
Make it accept `client_redirect_url=None`.
* Clean up interface for `SamlHandler.handle_redirect_request`
... bring it into line with CAS and OIDC by making it take a Request parameter,
move the magic for `client_redirect_url` for UIA into the handler, and fix the
return type to be a `str` rather than a `bytes`.
* Define a common protocol for SSO auth provider impls
* Give SsoIdentityProvider an ID and register them
* Combine the SSO Redirect servlets
Now that the SsoHandler knows about the identity providers, we can combine the
various *RedirectServlets into a single implementation which delegates to the
right IdP.
* changelog
The final part (for now) of my work to implement a username picker in synapse itself. The idea is that we allow
`UsernameMappingProvider`s to return `localpart=None`, in which case, rather than redirecting the browser
back to the client, we redirect to a username-picker resource, which allows the user to enter a username.
We *then* complete the SSO flow (including doing the client permission checks).
The static resources for the username picker itself (in
https://github.com/matrix-org/synapse/tree/rav/username_picker/synapse/res/username_picker)
are essentially lifted wholesale from
https://github.com/matrix-org/matrix-synapse-saml-mozilla/tree/master/matrix_synapse_saml_mozilla/res.
As the comment says, we might want to think about making them customisable, but that can be a follow-up.
Fixes#8876.
