From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56754) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TR4me-0001Fp-FN for qemu-devel@nongnu.org; Wed, 24 Oct 2012 13:30:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TR4mX-0005JL-Ty for qemu-devel@nongnu.org; Wed, 24 Oct 2012 13:30:22 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:41870) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TR4mX-0005EM-PO for qemu-devel@nongnu.org; Wed, 24 Oct 2012 13:30:17 -0400 Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 24 Oct 2012 13:30:06 -0400 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id C96A738C80A2 for ; Wed, 24 Oct 2012 13:30:03 -0400 (EDT) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q9OHU38h260788 for ; Wed, 24 Oct 2012 13:30:03 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q9OHU1Y8014337 for ; Wed, 24 Oct 2012 15:30:02 -0200 Message-ID: <50882598.5090100@linux.vnet.ibm.com> Date: Wed, 24 Oct 2012 13:30:00 -0400 From: Corey Bryant MIME-Version: 1.0 References: <1350479712-15082-1-git-send-email-otubo@linux.vnet.ibm.com> <1350479712-15082-4-git-send-email-otubo@linux.vnet.ibm.com> <50801D29.2080305@redhat.com> <5087F899.2030604@linux.vnet.ibm.com> <5088078B.3070002@redhat.com> <50880B96.20802@linux.vnet.ibm.com> <50880CFF.5010008@redhat.com> In-Reply-To: <50880CFF.5010008@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 4/4] Warning messages on net devices hotplug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: pmoore@redhat.com, aliguori@us.ibm.com, qemu-devel@nongnu.org, Eduardo Otubo On 10/24/2012 11:45 AM, Paolo Bonzini wrote: > Il 24/10/2012 17:39, Corey Bryant ha scritto: >> >> >> On 10/24/2012 11:21 AM, Paolo Bonzini wrote: >>> Il 24/10/2012 16:18, Corey Bryant ha scritto: >>>> >>>> >>>> On 10/18/2012 11:15 AM, Paolo Bonzini wrote: >>>>> Il 17/10/2012 15:15, Eduardo Otubo ha scritto: >>>>>> With the inclusion of the new "double whitelist" seccomp filter, Qemu >>>>>> won't be able to execve() in runtime, thus, no hotplug net devices >>>>>> allowed. >>>>>> >>>>>> Signed-off-by: Eduardo Otubo >>>>> >>>>> Please check this in net_init_tap instead. When using libvirt, hotplug >>>>> is done with a completely different mechanism that involves >>>>> file-descriptor passing and does not require executing a helper. >>>>> >>>>> Paolo >>>>> >>>> >>>> Are you sure net_init_tap() is the right place for this check? >>> >>> Yes, assuming there is a global that says whether the seccomp sandbox is >>> in effect. Even something like "if (sandbox_active && !tap->has_fd) >>> error(...)" can be enough. >>> >>> Paolo >>> >> >> What do you think about this? It moves the checks into the functions >> that actually cause execve() to be called, and it only prevents the >> commands after QEMU is done with initialization in main(). > > It doesn't do error reporting correctly because these functions do not > get an Error **. If you change that and use error_setg instead of > error_report, it should be okay. I just wanted to follow up on a few things.. All of the following functions currently use qerror_report(). I'm thinking conversion of these and sub-functions to pass an Error ** parameter should be a separate undertaking. net_init_nic net_init_slirp net_init_tap net_init_socket net_init_vde net_init_dump net_init_bridge net_init_hubport > > However, I really think what your testing is not > runstate_is_prelaunch(), it is seccomp_effective(). If you structure > the test like that, it also lets you eliminate the #ifdef (which in > general we prefer to avoid). The reason for testing runstate_is_prelaunch() is because seccomp will be effective during and after prelaunch. The only difference is that a more restrictive syscall whitelist will be in effect after prelaunch. So perhaps the tests can be similar to the following so that we can get rid of the preprocessor #ifdef: if (seccomp_is_effective() && !runstate_is_prelaunch()) { error_report("Cannot execute network helper from QEMU monitor " "when -sandbox is in effect"); return -1; } -- Regards, Corey Bryant