Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755221AbZGKTj1 (ORCPT ); Sat, 11 Jul 2009 15:39:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752495AbZGKTjS (ORCPT ); Sat, 11 Jul 2009 15:39:18 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:47677 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752390AbZGKTjS (ORCPT ); Sat, 11 Jul 2009 15:39:18 -0400 Date: Sat, 11 Jul 2009 12:39:44 -0700 From: Sukadev Bhattiprolu To: Oleg Nesterov Cc: roland@redhat.com, "Eric W. Biederman" , Oren Laadan , serue@us.ibm.com, Alexey Dobriyan , Containers , linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] Deny CLONE_PARENT|CLONE_NEWPID|CLONE_SIGHAND combination Message-ID: <20090711193944.GA32330@us.ibm.com> References: <20090701074045.GA14595@us.ibm.com> <20090702115740.GB3552@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090702115740.GB3552@redhat.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2024 Lines: 49 Oleg Nesterov [oleg@redhat.com] wrote: | On 07/01, Sukadev Bhattiprolu wrote: | > | > Deny CLONE_PARENT|CLONE_NEWPID|CLONE_SIGHAND 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[v2]: | > [Eric Biederman] Disable CLONE_SIGHAND also ??? | > | > Signed-off-by: Sukadev Bhattiprolu | > Acked-by: Roland McGrath | > --- | > 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 2009-06-30 23:01:09.000000000 -0700 | > +++ linux-mmotm/kernel/pid_namespace.c 2009-06-30 23:49:06.000000000 -0700 | > @@ -118,7 +118,7 @@ struct pid_namespace *copy_pid_ns(unsign | > { | > if (!(flags & CLONE_NEWPID)) | > return get_pid_ns(old_ns); | > - if (flags & CLONE_THREAD) | > + if (flags & (CLONE_THREAD|CLONE_PARENT|CLONE_SIGHAND)) | > return ERR_PTR(-EINVAL); | | Still can't understand why CLONE_SIGHAND is forbidden... | | CLONE_SIGHAND doesn't mean we share the signal queue, so what is | the reason? I don't have a convincing reason. We could disable just the CLONE_NEWPID|CLONE_PARENT combination till we have a need for it. We talked about removing CLONE_PARENT but backed-off since some application may be using it. Disabling specific combinations like this (CLONE_NEWPID is relatively a new flag) could make it a little easier to remove CLONE_PARENT in the future. Sukadev -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/