bid_main/models.py

@@ -544,6 +544,7 @@ class User(AbstractBaseUser, PermissionsMixin):
         return bid_main.file_utils.get_absolute_url(self.avatar.storage.url(default_thumbnail_path))
 
     def mfa_devices_per_type(self):
+        if not hasattr(self, '_mfa_devices'):
             devices_per_type = defaultdict(list)
             for device in devices_for_user(self):
                 if isinstance(device, EncryptedRecoveryDevice):
@@ -552,7 +553,8 @@ class User(AbstractBaseUser, PermissionsMixin):
                     devices_per_type['totp'].append(device)
                 if isinstance(device, U2fDevice):
                     devices_per_type['u2f'].append(device)
-        return devices_per_type
+            self._mfa_devices = devices_per_type
+        return self._mfa_devices
 
 
 class SettingValueField(models.CharField):

bid_main/templates/bid_main/components/mfa_form.html

@@ -8,10 +8,10 @@
   {% with form=form|add_form_classes %}
     <form role="login" action="" method="POST">{% csrf_token %}
       <fieldset class="mb-4">
-        {% if use_recovery %}
+        {% if mfa_device_type == 'recovery' %}
           <p>Use a recovery code</p>
           <input type="hidden" name="otp_device" value="{{ devices.recovery.0.persistent_id }}" />
-        {% else %}
+        {% elif mfa_device_type == 'totp' %}
           {% if devices.totp|length == 1 %}
             <input type="hidden" name="otp_device" value="{{ devices.totp.0.persistent_id }}" />
           {% else %}
@@ -36,13 +36,11 @@
       <button class="btn btn-block btn-accent">Continue</button>
     </form>
   {% endwith %}
-  {% if devices.recovery %}
+  {% if mfa_alternatives %}
   <div class="bid-links">
-  {% if use_recovery %}
-  <a href="?{% query_transform mfa_device_type='totp' %}">Use an authenticator</a>
-  {% else %}
-  <a href="?{% query_transform mfa_device_type='recovery' %}">Use a recovery code</a>
-  {% endif %}
+    {% for item in mfa_alternatives %}
+    <a href="{{ item.href }}">{{ item.label }}</a>
+    {% endfor %}
   </div>
   {% endif %}
 </div>

bid_main/templates/bid_main/components/u2f_form.html

@@ -26,10 +26,11 @@
       <div id="webauthn-error"></div>
     </form>
   {% endwith %}
-  {% if devices.totp %}
+  {% if mfa_alternatives %}
   <div class="bid-links">
-    <a href="?{% query_transform mfa_device_type='totp' %}">Use an authenticator</a>
-    <a href="?{% query_transform mfa_device_type='recovery' %}">Use a recovery code</a>
+    {% for item in mfa_alternatives %}
+    <a href="{{ item.href }}">{{ item.label }}</a>
+    {% endfor %}
   </div>
   {% endif %}
 </div>

bid_main/views/normal_pages.py

@@ -34,6 +34,7 @@ import oauth2_provider.models as oauth2_models
 from .. import forms, email
 from . import mixins
 from bid_main.email import send_verify_address
+from bid_main.templatetags.common import query_transform
 from mfa.fido2 import authenticate_begin
 from mfa.forms import MfaAuthenticateForm, U2fAuthenticateForm
 import bid_main.file_utils
@@ -87,11 +88,12 @@ class LoginView(mixins.RedirectToPrivacyAgreeMixin, mixins.PageIdMixin, django_o
       and django_otp makes use of that to switch between otp_authentication_form and otp_token_form
     - we overwrite otp_authentication_form to exclude the otp_device and otp_token fields, because
       we don't have mandatory MFA for everyone
-    On top of that we have a separate helper for injecting U2fAuthenticateForm if a user has a u2f
-    device.
+    On top of that we have additional logic in get_form for injecting U2fAuthenticateForm if a user
+    has a u2f device.
 
-    Because get_form is called on both GET and POST requests we put the branching logic there,
+    Because get_form is called on both GET and POST requests we put our branching logic there,
     following the example of django_otp.
+    Then get_context_data checks the form class and supplies the data needed by a corresponding UI.
     """
 
     otp_authentication_form = forms.AuthenticationForm
@@ -104,16 +106,39 @@ class LoginView(mixins.RedirectToPrivacyAgreeMixin, mixins.PageIdMixin, django_o
     authorize_url = reverse_lazy("oauth2_provider:authorize")
 
     def _mfa_device_type(self):
-        return self.request.GET.get("mfa_device_type", None)
+        default_type = None
+        available_types = self.request.user.mfa_devices_per_type()
+        if "u2f" in available_types:
+            default_type = "u2f"
+        elif "totp" in available_types:
+            default_type = "totp"
+        return self.request.GET.get("mfa_device_type", default_type)
 
-    def _use_recovery(self):
-        return self._mfa_device_type() == "recovery"
-
-    def _use_totp(self):
-        return self._mfa_device_type() == "totp"
-
-    def _use_u2f(self):
-        return self._mfa_device_type() == "u2f"
+    def _mfa_alternatives(self):
+        r = {"request": self.request}
+        alternatives = [
+            {
+                "href": "?" + query_transform(r, mfa_device_type="u2f"),
+                "label": _("Use U2F security key"),
+                "type": "u2f",
+            },
+            {
+                "href": "?" + query_transform(r, mfa_device_type="totp"),
+                "label": _("Use TOTP authenticator"),
+                "type": "totp",
+            },
+            {
+                "href": "?" + query_transform(r, mfa_device_type="recovery"),
+                "label": _("Use recovery code"),
+                "type": "recovery",
+            },
+        ]
+        available_types = self.request.user.mfa_devices_per_type()
+        mfa_device_type = self._mfa_device_type()
+        return [
+            item for item in alternatives
+            if item["type"] in available_types and item["type"] != mfa_device_type
+        ]
 
     @method_decorator(sensitive_post_parameters())
     @method_decorator(csrf_protect)
@@ -146,36 +171,41 @@ class LoginView(mixins.RedirectToPrivacyAgreeMixin, mixins.PageIdMixin, django_o
         if isinstance(form, U2fAuthenticateForm):
             ctx["devices"] = self.request.user.mfa_devices_per_type()
             ctx["form_type"] = "u2f"
+            ctx["mfa_alternatives"] = self._mfa_alternatives()
+            ctx["mfa_device_type"] = "u2f"
         elif isinstance(form, MfaAuthenticateForm):
             ctx["devices"] = self.request.user.mfa_devices_per_type()
-            ctx["use_recovery"] = self._use_recovery()
             ctx["form_type"] = "mfa"
+            ctx["mfa_alternatives"] = self._mfa_alternatives()
+            ctx["mfa_device_type"] = self._mfa_device_type()
 
         return ctx
 
     def _get_u2f_form(self, devices):
         credentials = [AttestedCredentialData(d.credential) for d in devices]
-        rp_id = self.request.get_host().split(':')[0]  # remove port, required by webauthn
+        rp_id = self.request.get_host().split(":")[0]  # remove port, required by webauthn
         request_options, state = authenticate_begin(rp_id, credentials)
         kwargs = self.get_form_kwargs()
-        kwargs['credentials'] = credentials
-        kwargs['request_options'] = json.dumps(dict(request_options))
-        kwargs['rp_id'] = rp_id
-        kwargs['state'] = dict(state)
+        kwargs["credentials"] = credentials
+        kwargs["request_options"] = json.dumps(dict(request_options))
+        kwargs["rp_id"] = rp_id
+        kwargs["state"] = dict(state)
         return U2fAuthenticateForm(**kwargs)
 
     def get_form(self):
         if self.request.user.is_authenticated:
-            devices = self.request.user.mfa_devices_per_type().get('u2f', None)
-            if devices and not self._use_recovery() and not self._use_totp():
-                return self._get_u2f_form(devices)
+            u2f_devices = self.request.user.mfa_devices_per_type().get("u2f")
+            mfa_device_type = self._mfa_device_type()
+            if u2f_devices and (not mfa_device_type or mfa_device_type == "u2f"):
+                return self._get_u2f_form(u2f_devices)
         # this will switch between MfaAuthenticateForm and AuthenticationForm
         # as defined in django_otp.views.LoginView.authentication_form implementation
         return super().get_form()
 
     def get_form_kwargs(self):
         kwargs = super().get_form_kwargs()
-        if self._use_recovery():
+        # this will affect only MfaAuthenticateForm, but making an explicit check here is cumbersome
+        if self.request.user.is_authenticated and self._mfa_device_type() == "recovery":
             kwargs["use_recovery"] = True
         return kwargs