Re: [PATCH v3 0/1] Relax restrictions on user.* xattr

[Miklos Szeredi]

On Tue, 7 Sept 2021 at 23:40, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
>
> On Mon, Sep 06, 2021 at 04:56:44PM +0200, Miklos Szeredi wrote:
> > On Mon, 6 Sept 2021 at 16:39, Dr. David Alan Gilbert
> > <dgilbert@xxxxxxxxxx> wrote:
> >
> > > IMHO the real problem here is that the user/trusted/system/security
> > > 'namespaces' are arbitrary hacks rather than a proper namespacing
> > > mechanism that allows you to create new (nested) namespaces and associate
> > > permissions with each one.
> >
> > Indeed.
> >
> > This is what Eric Biederman suggested at some point for supporting
> > trusted xattrs within a user namespace:
> >
> > | For trusted xattrs I think it makes sense in principle.   The namespace
> > | would probably become something like "trusted<ns-root-uid>.".
> >
> > Theory sounds simple enough.  Anyone interested in looking at the details?
>
> So this namespaced trusted.* xattr domain will basically avoid the need
> to have CAP_SYS_ADMIN in init_user_ns, IIUC.  I guess this is better
> than giving CAP_SYS_ADMIN in init_user_ns.

That's the objective, yes.  I think the trick is getting filesystems
to store yet another xattr type.

Thanks,
Miklos