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From:   Andy Lutomirski <luto@kernel.org>
Date:   Sat, 12 Oct 2019 16:08:54 -0700
Message-ID: <CALCETrVmYQ9xikif--RSAWhboY1yj=piEAEuPzisf+b+qEX4uA@mail.gmail.com>
Subject: Re: [PATCH 4/7] Teach SELinux about a new userfaultfd class
To:     Daniel Colascione <dancol@google.com>
Cc:     Linux API <linux-api@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, lokeshgidra@google.com,
        Nick Kralevich <nnk@google.com>, nosh@google.com,
        Tim Murray <timmurray@google.com>
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On Sat, Oct 12, 2019 at 12:16 PM Daniel Colascione <dancol@google.com> wrote:
>
> Use the secure anonymous inode LSM hook we just added to let SELinux
> policy place restrictions on userfaultfd use. The create operation
> applies to processes creating new instances of these file objects;
> transfer between processes is covered by restrictions on read, write,
> and ioctl access already checked inside selinux_file_receive.

This is great, and I suspect we'll want it for things like SGX, too.
But the current design seems like it will make it essentially
impossible for SELinux to reference an anon_inode class whose
file_operations are in a module, and moving file_operations out of a
module would be nasty.

Could this instead be keyed off a new struct anon_inode_class, an
enum, or even just a string?

--Andy