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Date:   Tue, 6 Mar 2018 15:46:36 -0700
From:   Tycho Andersen <tycho@tycho.ws>
To:     Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [PATCH bpf-next v8 00/11] Landlock LSM: Toward unprivileged
 sandboxing
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On Tue, Mar 06, 2018 at 10:33:17PM +0000, Andy Lutomirski wrote:
> >> Suppose I'm writing a container manager.  I want to run "mount" in the
> >> container, but I don't want to allow moun() in general and I want to
> >> emulate certain mount() actions.  I can write a filter that catches
> >> mount using seccomp and calls out to the container manager for help.
> >> This isn't theoretical -- Tycho wants *exactly* this use case to be
> >> supported.
> >
> > Well, I think this use case should be handled with something like
> > LD_PRELOAD and a helper library. FYI, I did something like this:
> > https://github.com/stemjail/stemshim
> 
> I doubt that will work for containers.  Containers that use user
> namespaces and, for example, setuid programs aren't going to honor
> LD_PRELOAD.

Or anything that calls syscalls directly, like go programs.

Tycho