Re: [PATCH bpf-next v8 08/11] landlock: Add ptrace restrictions

[Andy Lutomirski]

On Wed, Feb 28, 2018 at 12:00 AM, MickaÃl SalaÃn <mic@xxxxxxxxxxx> wrote:
>
> On 28/02/2018 00:23, Andy Lutomirski wrote:
>> On Tue, Feb 27, 2018 at 11:02 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>>> On Tue, Feb 27, 2018 at 10:14 PM, MickaÃl SalaÃn <mic@xxxxxxxxxxx> wrote:
>>>>
>>>
>>> I think you're wrong here.  Any sane container trying to use Landlock
>>> like this would also create a PID namespace.  Problem solved.  I still
>>> think you should drop this patch.
>
> Containers is one use case, another is build-in sandboxing (e.g. for web
> browserâ) and another one is for sandbox managers (e.g. Firejail,
> Bubblewrap, Flatpackâ). In some of these use cases, especially from a
> developer point of view, you may want/need to debug your applications
> (without requiring to be root). For nested Landlock access-controls
> (e.g. container + user session + web browser), it may not be allowed to
> create a PID namespace, but you still want to have a meaningful
> access-control.
>

The consideration should be exactly the same as for normal seccomp.
If I'm in a container (using PID namespaces + seccomp) and a run a web
browser, I can debug the browser.

If there's a real use case for adding this type of automatic ptrace
protection, then by all means, let's add it as a general seccomp
feature.