Workaround for user_saml-application to return lower-case realm when configured through environment-variable.

roles/install_nextcloud/README.md

@@ -562,6 +562,18 @@ The name may not be canon some times. (like **appName-x.y.z** instead of **appNa
 Changing a parameter, then running the role again while the app is already enabled will **not** update its configuration.
 -   this post_install process is tagged and can be called directly using the `--tags install_apps` option.
 
+#### Patch **user_saml** Application
+
+If you centrally administer your users and configure nextcloud to include users via LDAP as user-backend through e.g. `user_ldap` module and want to provide Single-sign-on, you may configure the `user_saml` application using the environment-variable `REMOTE_USER`. In this case, the returned principal contains an upper-case realm. This is undesirable when the user backend stores the principals with realm in lower-case, which is the case for `user_ldap`, because the case-sensitive lookup by `user_saml` module for the existing user would not find the existing user. A typical use-case is, when you run a Samba Domain Controller and manage your users centrally in the Domain and want to provide Single-Sign-On in Nextcloud.
+This patch adds a workaround to `SAMLController.php`, which converts the realm to lower-case. To activate this patch, you also need to define `user_saml` application in `nextcloud_apps`.
+```yaml
+nextcloud_apps:
+  user_saml:
+nextcloud_patch_user_saml_app: true
+```
+This patch is a modified version of the workaround proposed [here](https://github.com/nextcloud/user_saml/issues/118).
+Note: When `user_saml` application is updated, this patch will be overwritten. In this case you may re-apply the patch by calling directly using the `--tags patch_user_saml_app` option. The patch is implemented in a way, that it shall work even when `user_saml`-app (including the patched-file `SAMLController.php`) changes, i.e. it shall be robust against changes of the `user_saml`-app. By an educated guess it will work for future versions of `user_saml`, but in any case it would not change anything if the change to `SAMLController.php` would touch the sensitive code therein.
+
 ## Example Playbook
 ### Case 1: Installing a quick Nextcloud demo
 In some case, you may want to deploy quickly many instances of Nextcloud on multiple hosts for testing/demo purpose and don't want to tune the role's variables for each hosts: Just run the playbook without any additional variable (all default) !
@@ -592,7 +604,7 @@ You can choose the version channel to download a specific version of nextcloud.
 ### Case 2: Using letsencrypt with this role.
 This role is not designed to manage letsencrypt certificates. However you can still use your certificates with nextcloud.
 
-You must create first your certificates using a letsencrypt ACME client or an Ansible role like [this one] (https://github.com/jaywink/ansible-letsencrypt)
+You must create first your certificates using a letsencrypt ACME client or an Ansible role like [this one](https://github.com/jaywink/ansible-letsencrypt)
 
 then call _install_nextcloud_ by setting `nextcloud_tls_cert_method: "installed"`
 

roles/install_nextcloud/defaults/main.yml

@@ -118,6 +118,7 @@ nextcloud_tls_session_cache_size: 50m  # in Byte or human readable size notation
 # [APPS]
 nextcloud_apps: {}
 nextcloud_disable_apps: []
+nextcloud_patch_user_saml_app: false  # Apply Workaround to lower-case REALM for REMOTE_USER environment-variable.
 
 # [SYSTEM]
 # nextcloud_mysql_root_pwd: "secret"

roles/install_nextcloud/files/SAMLController.patch

@@ -0,0 +1,3 @@
+				if (isset($_SERVER['REMOTE_USER'])) {
+					$_SERVER['REMOTE_USER'] = strtolower($_SERVER['REMOTE_USER']);
+				}

roles/install_nextcloud/tasks/main.yml

@@ -89,6 +89,7 @@
     - nextcloud_apps is mapping
   tags:
     - install_apps
+    - patch_user_saml_app
   block:
     - name: "[NC apps] - lists the number of apps available in the instance."
       ansible.builtin.command: php occ app:list --output=json_pretty --no-warnings
@@ -110,8 +111,10 @@
       # do if the app is not enabled and ( (archive path is not "") or (app is disabled) )
       when:
         - item.key not in nc_available_apps.enabled
+        - ansible_run_tags is not search('patch_user_saml_app')
       with_dict: "{{ nextcloud_apps }}"
 
+
 - name: Add indices
   ansible.builtin.command: php occ db:add-missing-indices
   args:
@@ -122,3 +125,26 @@
   register: nc_indices_cmd
   changed_when: '"Done" not in nc_indices_cmd.stdout'
   when: nextcloud_install_db
+
+- name: "[Main] - Patch from the app 'user_saml' the file SAMLController.php."
+  when:
+    - nextcloud_patch_user_saml_app
+    - nc_available_apps.enabled['user_saml'] is defined or nc_available_apps.disabled['user_saml'] is defined
+  tags:
+    - patch_user_saml_app
+  vars:
+    pattern: '.*\$this->session->set\(.user_saml\.samlUserData.,\s+\$_SERVER\);.*'
+    file2patch: "{{ nextcloud_webroot + 'apps/user_saml/lib/Controller/SAMLController.php' }}"
+  block:
+    - name: "[Main] - Check if SAMLController.php can be patched."
+      ansible.builtin.slurp:
+        src: "{{ file2patch }}"
+      register: df_file
+
+    - name: "[Main] - Patch file SAMController.php."
+      ansible.builtin.blockinfile:
+        block: "{{ lookup('ansible.builtin.file', 'files/SAMLController.patch') }}"
+        path: "{{ file2patch }}"
+        insertbefore: "{{ pattern }}"
+        marker: "                                /** {mark} ANSIBLE MANAGED BLOCK */"
+      when: df_file.content | b64decode | regex_search(pattern)