From patchwork Mon May 7 13:03:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 10384107 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 60DBE60236 for ; Mon, 7 May 2018 13:03:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5F0B020121 for ; Mon, 7 May 2018 13:03:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5319F28702; Mon, 7 May 2018 13:03:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D7DE328B95 for ; Mon, 7 May 2018 13:03:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752317AbeEGND3 (ORCPT ); Mon, 7 May 2018 09:03:29 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43630 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752248AbeEGND1 (ORCPT ); Mon, 7 May 2018 09:03:27 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 308E181A8B88; Mon, 7 May 2018 13:03:27 +0000 (UTC) Received: from redhat.com (ovpn-123-58.rdu2.redhat.com [10.10.123.58]) by smtp.corp.redhat.com (Postfix) with SMTP id AD5C27C57; Mon, 7 May 2018 13:03:25 +0000 (UTC) Date: Mon, 7 May 2018 16:03:25 +0300 From: "Michael S. Tsirkin" To: Kevin Easton Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node Message-ID: <20180507155534-mutt-send-email-mst@kernel.org> References: <000000000000a5b2b1056a86e98c@google.com> <20180427154502.GA22544@la.guarana.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180427154502.GA22544@la.guarana.org> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 07 May 2018 13:03:27 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 07 May 2018 13:03:27 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mst@redhat.com' RCPT:'' Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 > --- > 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; Let's just init the msg though. OK it seems this is the best we can do for now, we need a new feature bit to fix it for 32 bit userspace on 64 bit kernels. Does the following help? Signed-off-by: Michael S. Tsirkin diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index f3bd8e9..58d9aec 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;