Reusable Media: Mifare Ultralight AES support (#3335)

src/pretix/base/media.py

@@ -49,6 +49,9 @@ class BaseMediaType:
     def handle_unknown(self, organizer, identifier, user, auth):
         pass
 
+    def handle_new(self, organizer, medium, user, auth):
+        pass
+
     def __str__(self):
         return str(self.verbose_name)
 
@@ -108,9 +111,43 @@ class NfcUidMediaType(BaseMediaType):
                 return m
 
 
+class NfcMf0aesMediaType(BaseMediaType):
+    identifier = 'nfc_mf0aes'
+    verbose_name = 'NFC Mifare Ultralight AES'
+    medium_created_by_server = False
+    supports_giftcard = True
+    supports_orderposition = False
+
+    def handle_new(self, organizer, medium, user, auth):
+        from pretix.base.models import GiftCard
+
+        if organizer.settings.get(f'reusable_media_type_{self.identifier}_autocreate_giftcard', as_type=bool):
+            with transaction.atomic():
+                gc = GiftCard.objects.create(
+                    issuer=organizer,
+                    expires=organizer.default_gift_card_expiry,
+                    currency=organizer.settings.get(f'reusable_media_type_{self.identifier}_autocreate_giftcard_currency'),
+                )
+                medium.linked_giftcard = gc
+                medium.save()
+                medium.log_action(
+                    'pretix.reusable_medium.linked_giftcard.changed',
+                    user=user, auth=auth,
+                    data={
+                        'linked_giftcard': gc.pk
+                    }
+                )
+                gc.log_action(
+                    'pretix.giftcards.created',
+                    user=user, auth=auth,
+                )
+                return medium
+
+
 MEDIA_TYPES = {
     m.identifier: m for m in [
         BarcodePlainMediaType(),
         NfcUidMediaType(),
+        NfcMf0aesMediaType(),
     ]
 }

src/pretix/base/migrations/0244_mediumkeyset.py

@@ -0,0 +1,35 @@
+# Generated by Django 3.2.18 on 2023-05-17 11:32
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0243_device_os_name_and_os_version'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='device',
+            name='rsa_pubkey',
+            field=models.TextField(null=True),
+        ),
+        migrations.CreateModel(
+            name='MediumKeySet',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False)),
+                ('public_id', models.BigIntegerField(unique=True)),
+                ('media_type', models.CharField(max_length=100)),
+                ('active', models.BooleanField(default=True)),
+                ('uid_key', models.BinaryField()),
+                ('diversification_key', models.BinaryField()),
+                ('organizer', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='medium_key_sets', to='pretixbase.organizer')),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='mediumkeyset',
+            constraint=models.UniqueConstraint(condition=models.Q(('active', True)), fields=('organizer', 'media_type'), name='keyset_unique_active'),
+        ),
+    ]

src/pretix/base/models/devices.py

@@ -166,6 +166,10 @@ class Device(LoggedModel):
         null=True,
         blank=False
     )
+    rsa_pubkey = models.TextField(
+        null=True,
+        blank=True,
+    )
     info = models.JSONField(
         null=True, blank=True,
     )

src/pretix/base/models/media.py

@@ -123,3 +123,25 @@ class ReusableMedium(LoggedModel):
         unique_together = (("identifier", "type", "organizer"),)
         index_together = (("identifier", "type", "organizer"), ("updated", "id"))
         ordering = "identifier", "type", "organizer"
+
+
+class MediumKeySet(models.Model):
+    organizer = models.ForeignKey('Organizer', on_delete=models.CASCADE, related_name='medium_key_sets')
+    public_id = models.BigIntegerField(
+        unique=True,
+    )
+    media_type = models.CharField(max_length=100)
+    active = models.BooleanField(default=True)
+    uid_key = models.BinaryField()
+    diversification_key = models.BinaryField()
+
+    objects = ScopedManager(organizer='organizer')
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                fields=["organizer", "media_type"],
+                condition=Q(active=True),
+                name="keyset_unique_active",
+            ),
+        ]

src/pretix/base/services/media.py

@@ -0,0 +1,72 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+import secrets
+
+from django.db import IntegrityError
+from django.db.models import Q
+from django_scopes import scopes_disabled
+
+from pretix.base.models import GiftCardAcceptance
+from pretix.base.models.media import MediumKeySet
+
+
+def create_nfc_mf0aes_keyset(organizer):
+    for i in range(20):
+        public_id = secrets.randbelow(2 ** 32)
+        uid_key = secrets.token_bytes(16)
+        diversification_key = secrets.token_bytes(16)
+        try:
+            return MediumKeySet.objects.create(
+                organizer=organizer,
+                media_type="nfc_mf0aes",
+                public_id=public_id,
+                diversification_key=diversification_key,
+                uid_key=uid_key,
+                active=True,
+            )
+        except IntegrityError:  # either race condition with another thread or duplicate public ID
+            try:
+                return MediumKeySet.objects.get(
+                    organizer=organizer,
+                    media_type="nfc_mf0aes",
+                    active=True,
+                )
+            except MediumKeySet.DoesNotExist:
+                continue  # duplicate public ID, let's try again
+
+
+@scopes_disabled()
+def get_keysets_for_organizer(organizer):
+    sets = list(MediumKeySet.objects.filter(
+        Q(organizer=organizer) | Q(organizer__in=GiftCardAcceptance.objects.filter(
+            acceptor=organizer,
+            active=True,
+            reusable_media=True,
+        ).values_list("issuer_id", flat=True))
+    ))
+    if organizer.settings.reusable_media_type_nfc_mf0aes and not any(
+        ks.organizer == organizer and ks.media_type == "nfc_mf0aes" for ks in sets
+    ):
+        new_set = create_nfc_mf0aes_keyset(organizer)
+        if new_set:
+            sets.append(new_set)
+    return sets

src/pretix/base/settings.py

@@ -259,6 +259,46 @@ DEFAULTS = {
             label=_("Gift card currency"),
         )
     },
+    'reusable_media_type_nfc_mf0aes': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Active"),
+        )
+    },
+    'reusable_media_type_nfc_mf0aes_autocreate_giftcard': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Automatically create a new gift card if a new chip is encoded"),
+        )
+    },
+    'reusable_media_type_nfc_mf0aes_autocreate_giftcard_currency': {
+        'default': 'EUR',
+        'type': str,
+        'form_class': forms.ChoiceField,
+        'serializer_class': serializers.ChoiceField,
+        'serializer_kwargs': dict(
+            choices=[(c.alpha_3, c.alpha_3 + " - " + c.name) for c in settings.CURRENCIES],
+        ),
+        'form_kwargs': dict(
+            choices=[(c.alpha_3, c.alpha_3 + " - " + c.name) for c in settings.CURRENCIES],
+            label=_("Gift card currency"),
+        )
+    },
+    'reusable_media_type_nfc_mf0aes_random_uid': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Use UID protection feature of NFC chip"),
+        )
+    },
     'max_items_per_order': {
         'default': '10',
         'type': int,
@@ -3657,14 +3697,10 @@ def validate_organizer_settings(organizer, settings_dict):
     # This is not doing anything for the time being.
     # But earlier we called validate_event_settings for the organizer, too - and that didn't do anything for
     # organizer-settings either.
-    #
-    # N.B.: When actually fleshing out this stub, adding it to the OrganizerUpdateForm should be considered.
-    """
-    if settings_dict.get('reusable_media_type_ntag_pretix1') and settings_dict.get('reusable_media_type_nfc_uid'):
+    if settings_dict.get('reusable_media_type_nfc_mf0aes') and settings_dict.get('reusable_media_type_nfc_uid'):
         raise ValidationError({
             'reusable_media_type_nfc_uid': _('This needs to be disabled if other NFC-based types are active.')
         })
-    """
 
 
 def global_settings_object(holder):