Closes: #15842 - Option to hide local login form if SSO is in use (#18924)

Closes: #15842

Branched from #18145 by @tobiasge

Provides a new LOGIN_FORM_HIDDEN setting which allows the administrator to hide the local login form, intended only to be used when SSO is used exclusively for authentication. Note that this means local login will be impossible in the event of SSO provider issues, and can be remedied only through a change to the application config and a restart of the service.


* #15842 - Hide login form

This doesn't implement the full solution proposed in #15842 but enables
administrators to hide the login form when users should only login with a SSO
provider. To prevent a complete lockout when the SSO provider is having
issues the GET parameter `skipsso` can be added to the login URL to show
the form regardless.

* Remove skipsso backdoor

* Add warning

---------

Co-authored-by: Tobias Genannt <tobias.genannt@qbeyond.de>

docs/configuration/security.md

@@ -186,6 +186,17 @@ The lifetime (in seconds) of the authentication cookie issued to a NetBox user u
 
 ---
 
+## LOGIN_FORM_HIDDEN
+
+Default: False
+
+Option to hide the login form when only SSO authentication is in use. 
+
+!!! warning
+    If the SSO provider is unreachable, login to NetBox will be impossible if this option is enabled. The only recourse is to disable it in the local configuration and restart the NetBox service.
+
+---
+
 ## LOGOUT_REDIRECT_URL
 
 Default: `'home'`

netbox/account/views.py

@@ -89,10 +89,12 @@ class LoginView(View):
         if request.user.is_authenticated:
             logger = logging.getLogger('netbox.auth.login')
             return self.redirect_to_next(request, logger)
+        login_form_hidden = settings.LOGIN_FORM_HIDDEN
 
         return render(request, self.template_name, {
             'form': form,
             'auth_backends': self.get_auth_backends(request),
+            'login_form_hidden': login_form_hidden,
         })
 
     def post(self, request):

netbox/netbox/configuration_example.py

@@ -164,6 +164,9 @@ LOGIN_REQUIRED = True
 # re-authenticate. (Default: 1209600 [14 days])
 LOGIN_TIMEOUT = None
 
+# Hide the login form. Useful when only allowing SSO authentication.
+LOGIN_FORM_HIDDEN = False
+
 # The view name or URL to which users are redirected after logging out.
 LOGOUT_REDIRECT_URL = 'home'
 

netbox/netbox/settings.py

@@ -129,6 +129,7 @@ LOGGING = getattr(configuration, 'LOGGING', {})
 LOGIN_PERSISTENCE = getattr(configuration, 'LOGIN_PERSISTENCE', False)
 LOGIN_REQUIRED = getattr(configuration, 'LOGIN_REQUIRED', True)
 LOGIN_TIMEOUT = getattr(configuration, 'LOGIN_TIMEOUT', None)
+LOGIN_FORM_HIDDEN = getattr(configuration, 'LOGIN_FORM_HIDDEN', False)
 LOGOUT_REDIRECT_URL = getattr(configuration, 'LOGOUT_REDIRECT_URL', 'home')
 MEDIA_ROOT = getattr(configuration, 'MEDIA_ROOT', os.path.join(BASE_DIR, 'media')).rstrip('/')
 METRICS_ENABLED = getattr(configuration, 'METRICS_ENABLED', False)

netbox/templates/login.html

@@ -34,48 +34,55 @@
       {% endif %}
 
       <div class="card card-md">
-        <div class="card-body">
-          <h2 class="text-center mb-4">{% trans "Log In" %}</h2>
+        {% if not login_form_hidden %}
+          <div class="card-body">
+            <h2 class="text-center mb-4">{% trans "Log In" %}</h2>
 
-          {# Login form #}
-          <form action="{% url 'login' %}" method="post">
-            {% csrf_token %}
+            {# Login form #}
+            <form action="{% url 'login' %}" method="post">
+              {% csrf_token %}
 
-            {# Set post-login URL #}
-            {% if 'next' in request.GET %}
-              <input type="hidden" name="next" value="{{ request.GET.next }}" />
-            {% elif 'next' in request.POST %}
-              <input type="hidden" name="next" value="{{ request.POST.next }}" />
-            {% endif %}
+              {# Set post-login URL #}
+              {% if 'next' in request.GET %}
+                <input type="hidden" name="next" value="{{ request.GET.next }}" />
+              {% elif 'next' in request.POST %}
+                <input type="hidden" name="next" value="{{ request.POST.next }}" />
+              {% endif %}
 
-            <div class="form-group mb-3">
-              <label for="id_username" class="form-label">{{ form.username.label }}</label>
-              {{ form.username }}
-              {% for error in form.username.errors %}
-                <div class="alert alert-danger">{{ error }}</div>
-              {% endfor %}
-            </div>
+              <div class="form-group mb-3">
+                <label for="id_username" class="form-label">{{ form.username.label }}</label>
+                {{ form.username }}
+                {% for error in form.username.errors %}
+                  <div class="alert alert-danger">{{ error }}</div>
+                {% endfor %}
+              </div>
 
-            <div class="form-group">
-              <label for="id_password" class="form-label">{{ form.password.label }}</label>
-              {{ form.password }}
-              {% for error in form.password.errors %}
-                <div class="alert alert-danger">{{ error }}</div>
-              {% endfor %}
-            </div>
+              <div class="form-group">
+                <label for="id_password" class="form-label">{{ form.password.label }}</label>
+                {{ form.password }}
+                {% for error in form.password.errors %}
+                  <div class="alert alert-danger">{{ error }}</div>
+                {% endfor %}
+              </div>
 
-            <div class="form-footer">
-              <button type="submit" class="btn btn-primary w-100">
-                {% trans "Sign In" %}
-              </button>
-            </div>
-          </form>
-        </div>
+              <div class="form-footer">
+                <button type="submit" class="btn btn-primary w-100">
+                  {% trans "Sign In" %}
+                </button>
+              </div>
+            </form>
+          </div>
+        {% endif %}
 
         {# SSO login #}
         {% if auth_backends %}
-          <div class="hr-text">{% trans "Or" context "Denotes an alternative option" %}</div>
+          {% if not login_form_hidden %}
+            <div class="hr-text">{% trans "Or" context "Denotes an alternative option" %}</div>
+          {% endif %}
           <div class="card-body">
+            {% if login_form_hidden %}
+              <h2 class="text-center mb-4">{% trans "Log In" %}</h2>
+            {% endif %}
             <div class="row">
               {% for backend in auth_backends %}
                 <div class="col">