From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752982AbeFDMfQ (ORCPT ); Mon, 4 Jun 2018 08:35:16 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:45886 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752399AbeFDMfN (ORCPT ); Mon, 4 Jun 2018 08:35:13 -0400 X-Google-Smtp-Source: ADUXVKKnMjzhM4CE2u0SlOlxj1xHKYwI/07F6be4DpCyZ82ZZSomL/WzAPOW2MQzljJqIIkGb+p/5t518r8dOaMUv5s= MIME-Version: 1.0 In-Reply-To: <20180530055704-mutt-send-email-mst@kernel.org> References: <20180427154502.GA22544@la.guarana.org> <20180529221908.GA22742@roeck-us.net> <20180530055704-mutt-send-email-mst@kernel.org> From: Dmitry Vyukov Date: Mon, 4 Jun 2018 14:34:52 +0200 Message-ID: Subject: Re: [net] vhost: Use kzalloc() to allocate vhost_msg_node To: "Michael S. Tsirkin" Cc: Guenter Roeck , Kevin Easton , Jason Wang , KVM list , virtualization@lists.linux-foundation.org, netdev , LKML , syzkaller-bugs Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 30, 2018 at 5:01 AM, Michael S. Tsirkin wrote: > On Tue, May 29, 2018 at 03:19:08PM -0700, Guenter Roeck wrote: >> On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote: >> > The struct vhost_msg within struct vhost_msg_node is copied to userspace, >> > so it should be allocated with kzalloc() to ensure all structure padding >> > is zeroed. >> > >> > Signed-off-by: Kevin Easton >> > Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com >> >> Is this patch going anywhere ? >> >> The patch fixes CVE-2018-1118. It would be useful to understand if and when >> this problem is going to be fixed. >> >> Thanks, >> Guenter >> > --- >> > drivers/vhost/vhost.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> > index f3bd8e9..1b84dcff 100644 >> > --- a/drivers/vhost/vhost.c >> > +++ b/drivers/vhost/vhost.c >> > @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify); >> > /* Create a new message. */ >> > struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) >> > { >> > - struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); >> > + struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL); >> > if (!node) >> > return NULL; >> > node->vq = vq; > > As I pointed out, we don't need to init the whole structure. The proper > fix is thus (I think) below. > > Could you use your testing infrastructure to confirm this fixes the issue? Hi Michael, syzbot is self-service, see: https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches > Thanks! > > Signed-off-by: Michael S. Tsirkin > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f3bd8e941224..58d9aec90afb 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2342,6 +2342,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) > struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); > if (!node) > return NULL; > + > + /* Make sure all padding within the structure is initialized. */ > + memset(&node->msg, 0, sizeof node->msg); > node->vq = vq; > node->msg.type = type; > return node; > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20180530055704-mutt-send-email-mst%40kernel.org. > For more options, visit https://groups.google.com/d/optout.