linux-kernel - Re: [RFC PATCH v1 0/6] proc: Add allowlist for procfs files

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Date:   Tue, 31 Jan 2023 14:53:46 +0100
From:   Alexey Gladkov <legion@...nel.org>
To:     Christian Brauner <brauner@...nel.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>, containers@...ts.linux.dev,
        linux-fsdevel@...r.kernel.org,
        Alexey Dobriyan <adobriyan@...il.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        Val Cowan <vcowan@...hat.com>
Subject: Re: [RFC PATCH v1 0/6] proc: Add allowlist for procfs files

On Thu, Jan 26, 2023 at 02:39:30PM +0100, Alexey Gladkov wrote:
> > In general, such flexibility belongs into userspace imho.
> > 
> > Frankly, if that is really required it would almost make more sense to
> > be able to attach a new bpf program type to procfs that would allow to
> > filter procfs entries. Then the filter could be done purely in
> > userspace. If signed bpf lands one could then even ship signed programs
> > that are attachable by userns root.
> 
> I'll ask the podman developers how much more comfortable they would be
> using bpf to control file visibility in procfs. thanks for the idea.

I write for history.

After digging into eBPF, I came to the conclusion that nothing needs to be
done in kernel space. Access can be controlled via "lsm/file_open". Access
can be controlled per cgroup or per mountpoint, depending on the task.
Each project has its own choice.

Many thanks for pointing out eBPF.

-- 
Rgrds, legion