From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932874AbeD0QZn (ORCPT ); Fri, 27 Apr 2018 12:25:43 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:40650 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758610AbeD0QZl (ORCPT ); Fri, 27 Apr 2018 12:25:41 -0400 X-Google-Smtp-Source: AB8JxZodcemdiQefybSCgnGYt1awyUUanF5h+nFiUt5TvL4DHOomDlz5MO3Qrs0HxBiaTY5ev/QG0oZWhRAuuho5U4I= MIME-Version: 1.0 In-Reply-To: <20180427191430-mutt-send-email-mst@kernel.org> References: <000000000000a5b2b1056a86e98c@google.com> <20180427154502.GA22544@la.guarana.org> <20180427185501-mutt-send-email-mst@kernel.org> <20180427191430-mutt-send-email-mst@kernel.org> From: Dmitry Vyukov Date: Fri, 27 Apr 2018 18:25:19 +0200 Message-ID: Subject: Re: [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node To: "Michael S. Tsirkin" Cc: 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 Fri, Apr 27, 2018 at 6:15 PM, Michael S. Tsirkin 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 >> > >> > Does it help if a patch naming the padding is applied, >> > and then we init just the relevant field? >> > Just curious. >> >> Yes, it would help. > > I think it's slightly better that way then. node has a lot of internal > stuff we don't care to init. Would you mind taking my patch and building > on top of that then? But it's asking for more information leaks in future. This looks like work for compiler. >> >> --- >> >> 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; >> >> -- >> >> 2.8.1