Re: namespaces compatibility list

[Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>]

Eric W. Biederman wrote:
> Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org> writes:
>> right. I think we can address Ulrich concerns first because we have 
>> a solution for it (which looks like unsharing all namespaces at once,
>> here comes back the container object story :)
> 
> It doesn't work because we can't create a fresh mount namespace.
> 
> We need to create all new mounts (and deny access to the old ones)
> if we want to prevent all possibility of user space goof ups.
> 
> While that is easy enough to build an application to do we can't
> easily enforce that in the kernel.  Currently this is all
> CAP_SYS_ADMIN so only root can do this anyway.  So we can easily
> say don't do that then.
> 
> Clone flag consistency checking should only be used to enforce
> cases where the kernel side cannot support correctly.  Currently
> the kernel has no problems with the current mix and match possibilities
> short of implementation deficiencies.  So I do not see us
> addressing Ulrich's concerns with clone flags.

ACK :) Since this all is CAP_SYS_ADMIN-ed we can do with just a warning.

> Eric
>