Re: [PATCH] Deny CLONE_PARENT|CLONE_NEWPID combination

["Serge E. Hallyn" <serue@us.ibm.com>]

Quoting Sukadev Bhattiprolu (sukadev@linux.vnet.ibm.com):
> 
> Deny CLONE_PARENT|CLONE_NEWPID combination.
> 
> CLONE_PARENT was used to implement an older threading model.  For consistency
> with the CLONE_THREAD check in copy_pid_ns(), disable CLONE_PARENT and
> CLONE_SIGHAND with CLONE_NEWPID, at least until the required semantics of
> the pid namespaces are clear.
> 
> Changelog[v3]:
> 	Remove CLONE_SIGHAND and for now only fail CLONE_NEWPID|CLONE_PARENT.

(FWIW your patch description does not reflect this...)

> Changelog[v2]:
> 	[Eric Biederman] Disable CLONE_SIGHAND also ?
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
> Acked-by: Roland McGrath <roland@redhat.com>
> Acked-by: Serge Hallyn <serue@us.ibm.com>
> ---
>  kernel/pid_namespace.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-mmotm/kernel/pid_namespace.c
> ===================================================================
> --- linux-mmotm.orig/kernel/pid_namespace.c	2009-07-16 10:03:01.000000000 -0700
> +++ linux-mmotm/kernel/pid_namespace.c	2009-07-16 11:37:24.000000000 -0700
> @@ -118,7 +118,7 @@
>  {
>  	if (!(flags & CLONE_NEWPID))
>  		return get_pid_ns(old_ns);
> -	if (flags & CLONE_THREAD)
> +	if (flags & (CLONE_THREAD|CLONE_PARENT))
>  		return ERR_PTR(-EINVAL);
>  	return create_pid_namespace(old_ns);
>  }