BooksStack's OIDC Client requests the 'profile' and 'email' scope values
in order to have access to the 'name', 'email', and other claims. It
looks for these claims in the ID Token that is returned along with the
Access Token.
However, the OIDC-core specification section 5.4 [1] only requires that
the Provider include those claims in the ID Token *if* an Access Token is
not also issued. If an Access Token is issued, the Provider can leave out
those claims from the ID Token, and the Client is supposed to obtain them
by submitting the Access Token to the UserInfo Endpoint.
So I suppose it's just good luck that the OIDC Providers that BookStack
has been tested with just so happen to also stick those claims in the ID
Token even though they don't have to. But others (in particular:
https://login.infomaniak.com) don't do so, and require fetching the
UserInfo Endpoint.)
A workaround is currently possible by having the user write a theme with a
ThemeEvents::OIDC_ID_TOKEN_PRE_VALIDATE hook that fetches the UserInfo
Endpoint. This workaround isn't great, for a few reasons:
1. Asking the user to implement core parts of the OIDC protocol is silly.
2. The user either needs to re-fetch the .well-known/openid-configuration
file to discover the endpoint (adding yet another round-trip to each
login) or hard-code the endpoint, which is fragile.
3. The hook doesn't receive the HTTP client configuration.
So, have BookStack's OidcService fetch the UserInfo Endpoint and inject
those claims into the ID Token, if a UserInfo Endpoint is defined.
Two points about this:
- Injecting them into the ID Token's claims is the most obvious approach
given the current code structure; though I'm not sure it is the best
approach, perhaps it should instead fetch the user info in
processAuthorizationResponse() and pass that as an argument to
processAccessTokenCallback() which would then need a bit of
restructuring. But this made sense because it's also how the
ThemeEvents::OIDC_ID_TOKEN_PRE_VALIDATE hook works.
- OIDC *requires* that a UserInfo Endpoint exists, so why bother with
that "if a UserInfo Endpoint is defined" bit? Simply out of an
abundance of caution that there's an existing BookStack user that is
relying on it not fetching the UserInfo Endpoint in order to work with
a non-compliant OIDC Provider.
[1]: https://openid.net/specs/openid-connect-core-1_0.html#ScopeClaims
