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

[Vivek Goyal]

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 at redhat.com> 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.

Vivek