Docs: update Kanidm setup instruction (#53)

* Update Kanidm setup instruction

* docs(kanidm): add tokenValidation to solve missing claims

* docs(kanidm): improve presentation

* docs(kanidm): further improve presentation

(cherry picked from commit d80dcd1)

website/docs/identity-providers/kanidm.md

@@ -4,6 +4,150 @@ sidebar_position: 3
 
 # Kanidm
 
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
 [Website Link](https://github.com/kanidm/kanidm)
 
-See [this Github Issue](https://github.com/sevensolutions/traefik-oidc-auth/issues/12) for details.
+## Setup Kanidm
+
+To create or manage OAuth2 clients, you should use [kanidm client](https://kanidm.github.io/kanidm/stable/client_tools.html) and be a member of the `system_admins` or `idm_hp_oauth2_manage_priv` groups.
+
+1. Create a new OAuth2 client
+   ```shell
+   kanidm system oauth2 create <client_id> <displayname> <landing page url>
+   ```
+2. Update a scope map to be able to use the client within OpenID Connect (OIDC)
+   ```shell
+   kanidm system oauth2 update-scope-map <client_id> <group_name> opened
+   ```
+   You might also want to include other scopes here, e.g. `profile`, `email` or `groups`
+   ```shell
+   kanidm system oauth2 update-scope-map <client_id> <group_name> openid profile email groups
+   ```
+   You can use `idm_all_persons` as a `<group_name>` if you are fine with all receiving having access to the client.
+3. Add a redirect URL, where you specify the public URL of your application and append the path `/oidc/callback`
+   ```shell
+   kanidm system oauth2 add-redirect-url <client_id> https://login.example.com/oidc/callback
+   ```
+   You might need to add all your subdomains where you plan to use this middleware or use [Absolute URL](../getting-started/callback-uri.md#absolute-url) configuration.
+4. Let's verify what we have now
+   ```shell
+   kanidm system oauth2 get <client_id>
+   ```
+   In the example below `traefik-oauth2` is the `<client_id>`
+   ```yaml
+    class: account
+    class: memberof
+    class: oauth2_resource_server
+    class: oauth2_resource_server_basic
+    class: object
+    directmemberof: [email protected]
+    displayname: Traefik OAuth
+    es256_private_key_der: private_binary
+    memberof: [email protected]
+    name: traefik-oauth2
+    oauth2_allow_insecure_client_disable_pkce: true
+    oauth2_rs_basic_secret: hidden
+    oauth2_rs_origin: https://login.example.com/oidc/callback
+    oauth2_rs_origin_landing: https://login.example.com/
+    oauth2_rs_scope_map: [email protected]: {"email", "groups", "openid", "profile"}
+    oauth2_rs_token_key: hidden
+    oauth2_strict_redirect_uri: true
+    spn: [email protected]
+    uuid: f1f4e707-832e-4beb-ba12-9410b883dddf
+   ```
+
+You will find all Kanidm configuration options in [the documentation](https://kanidm.github.io/kanidm/stable/integrations/oauth2.html).
+
+:::tip
+Before you start, make sure your Kanidm has a valid (and not self-signed) TLS certificate and `idm.example.com` is accessible from the Traefik container/host.
+:::
+
+## Middleware Configuration
+
+:::tip
+To display the client's secret, use `kanidm system oauth2 show-basic-secret <client_id>`
+:::
+
+<Tabs groupId="type">
+  <TabItem value="relative-secure" label="Relative URL with PKCE">
+
+```yml
+http:
+  middlewares:
+    oidc-auth:
+      plugin:
+        traefik-oidc-auth:
+          Provider:
+            Url: "https://idm.example.com/oauth2/openid/<client_id>"
+            ClientId: "<client_id>"
+            TokenValidation: "IdToken"
+            UsePkce: true
+          Scopes: ["openid", "profile"]
+```
+
+  </TabItem>
+  <TabItem value="relative" label="Relative URL without PKCE">
+
+```yml
+http:
+  middlewares:
+    oidc-auth:
+      plugin:
+        traefik-oidc-auth:
+          Provider:
+            Url: "https://idm.example.com/oauth2/openid/<client_id>"
+            ClientId: "<client_id>"
+            ClientSecret: "<client_secret>"
+            TokenValidation: "IdToken"
+          Scopes: ["openid", "profile"]
+```
+
+  </TabItem>
+  <TabItem value="absolute" label="Absolute URL without PKCE and Forward Auth headers">
+
+```yml
+http:
+  middlewares:
+    oidc-auth:
+      plugin:
+        traefik-oidc-auth:
+          LogLevel: DEBUG
+          CallbackUri: "https://login.example.com/oidc/callback"
+          SessionCookie:
+            Domain: ".example.com"
+          Provider:
+            Url: "https://idm.example.com/oauth2/openid/<client_id>"
+            ClientId: "<client_id>"
+            ClientSecret: "<client_secret>"
+            TokenValidation: "IdToken"
+            UsePkce: false
+          Scopes: ["openid", "profile", "email", "groups"]
+          Headers:
+            - Name: "Remote-User"
+              Value: "{{`{{ .claims.preferred_username }}`}}"
+            - Name: "Remote-Email"
+              Value: "{{`{{ .claims.email }}`}}"
+            - Name: "Remote-Groups"
+              Value: "{{`{{ .claims.groups }}`}}"
+            - Name: "Remote-Name"
+              Value: "{{`{{ .claims.name }}`}}"
+
+  routers:
+    auth:
+      rule: "Host(`login.example.com)"
+      service: noop@internal
+      middlewares: ["oidc-auth@file"]
+```
+
+  </TabItem>
+</Tabs>
+
+:::note
+You need to set `TokenValidation` to `IdToken` to populate claims. Otherwise, they do not include any scopes.
+:::
+
+:::note
+Kanidm enforces PKCE by default. To disable this behaviour use `kanidm system oauth2 warning-insecure-client-disable-pkce <client_id>`
+:::