    def __call__(self, request):
        file_fields = request.POST.getlist("s3file")
        for field_name in file_fields:
            paths = request.POST.getlist(field_name)
            request.FILES.setlist(field_name, list(self.get_files_from_storage(paths)))

        if local_dev and request.path == "/__s3_mock__/":
            return views.S3MockView.as_view()(request)

        return self.get_response(request)
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.