[SECURITY] Bind relevant cached file downloads to the current session

src/pretix/base/migrations/0162b_auto_20201218_1810.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.0.11 on 2020-12-18 18:10
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0173_auto_20201211_1648'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='cachedfile',
+            name='session_key',
+            field=models.TextField(null=True),
+        ),
+        migrations.AddField(
+            model_name='cachedfile',
+            name='web_download',
+            field=models.BooleanField(default=True),
+        ),
+    ]

src/pretix/base/models/base.py

@@ -28,6 +28,8 @@ class CachedFile(models.Model):
     filename = models.CharField(max_length=255)
     type = models.CharField(max_length=255)
     file = models.FileField(null=True, blank=True, upload_to=cachedfile_name, max_length=255)
+    web_download = models.BooleanField(default=True)  # allow web download, True for backwards compatibility in plugins
+    session_key = models.TextField(null=True, blank=True)  # only allow download in this session
 
 
 @receiver(post_delete, sender=CachedFile)

src/pretix/base/services/shredder.py

@@ -17,7 +17,7 @@ from pretix.celery_app import app
 
 
 @app.task(base=ProfiledEventTask)
-def export(event: Event, shredders: List[str]) -> None:
+def export(event: Event, shredders: List[str], session_key=None) -> None:
     known_shredders = event.get_data_shredders()
 
     with NamedTemporaryFile() as rawfile:
@@ -54,7 +54,9 @@ def export(event: Event, shredders: List[str]) -> None:
         cf = CachedFile()
         cf.date = now()
         cf.filename = event.slug + '.zip'
-        cf.type = 'application/pdf'
+        cf.type = 'application/zip'
+        cf.session_key = session_key
+        cf.web_download = True
         cf.expires = now() + timedelta(hours=1)
         cf.save()
         cf.file.save(cachedfile_name(cf, cf.filename), rawfile)

src/pretix/base/views/cachedfiles.py

@@ -13,7 +13,11 @@ class DownloadView(TemplateView):
     @cached_property
     def object(self) -> CachedFile:
         try:
-            return get_object_or_404(CachedFile, id=self.kwargs['id'])
+            o = get_object_or_404(CachedFile, id=self.kwargs['id'], web_download=True)
+            if o.session_key:
+                if o.session_key != self.request.session.session_key:
+                    raise Http404()
+            return o
         except ValueError:   # Invalid URLs
             raise Http404()
 

src/pretix/control/views/orders.py

@@ -1956,7 +1956,7 @@ class ExportDoView(EventPermissionRequiredMixin, ExportMixin, AsyncAction, View)
             messages.error(self.request, _('There was a problem processing your input. See below for error details.'))
             return self.get(request, *args, **kwargs)
 
-        cf = CachedFile()
+        cf = CachedFile(web_download=True, session_key=request.session.session_key)
         cf.date = now()
         cf.expires = now() + timedelta(days=3)
         cf.save()

src/pretix/control/views/organizer.py

@@ -1238,7 +1238,7 @@ class ExportDoView(OrganizerPermissionRequiredMixin, ExportMixin, AsyncAction, V
             messages.error(self.request, _('There was a problem processing your input. See below for error details.'))
             return self.get(request, *args, **kwargs)
 
-        cf = CachedFile()
+        cf = CachedFile(web_download=True, session_key=request.session.session_key)
         cf.date = now()
         cf.expires = now() + timedelta(days=3)
         cf.save()

src/pretix/control/views/pdf.py

@@ -137,7 +137,7 @@ class BaseEditorView(EventPermissionRequiredMixin, TemplateView):
             buffer = BytesIO()
             p.write(buffer)
             buffer.seek(0)
-            c = CachedFile()
+            c = CachedFile(web_download=True)
             c.expires = now() + timedelta(days=7)
             c.date = now()
             c.filename = 'background_preview.pdf'
@@ -162,7 +162,7 @@ class BaseEditorView(EventPermissionRequiredMixin, TemplateView):
                     "status": "error",
                     "error": error
                 })
-            c = CachedFile()
+            c = CachedFile(web_download=True)
             c.expires = now() + timedelta(days=7)
             c.date = now()
             c.filename = 'background_preview.pdf'

src/pretix/control/views/shredder.py

@@ -75,7 +75,7 @@ class ShredExportView(RecentAuthenticationRequiredMixin, EventPermissionRequired
         if constr:
             return self.error(ShredError(self.get_error_url()))
 
-        return self.do(self.request.event.id, request.POST.getlist("shredder"))
+        return self.do(self.request.event.id, request.POST.getlist("shredder"), self.request.session.session_key)
 
 
 class ShredDoView(RecentAuthenticationRequiredMixin, EventPermissionRequiredMixin, ShredderMixin, AsyncAction, View):

src/pretix/plugins/badges/views.py

@@ -235,7 +235,7 @@ class OrderPrintDo(EventPermissionRequiredMixin, AsyncAction, View):
 
     def post(self, request, *args, **kwargs):
         order = get_object_or_404(self.request.event.orders, code=request.GET.get("code"))
-        cf = CachedFile()
+        cf = CachedFile(web_download=True, session_key=self.request.session.session_key)
         cf.date = now()
         cf.type = 'application/pdf'
         cf.expires = now() + timedelta(days=3)