From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58988 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752865AbeFXPaZ (ORCPT ); Sun, 24 Jun 2018 11:30:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kevin Easton , "Michael S. Tsirkin" , syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com Subject: [PATCH 4.14 50/52] vhost: fix info leak due to uninitialized memory Date: Sun, 24 Jun 2018 23:21:43 +0800 Message-Id: <20180624142747.352454563@linuxfoundation.org> In-Reply-To: <20180624142744.234164867@linuxfoundation.org> References: <20180624142744.234164867@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael S. Tsirkin commit 670ae9caaca467ea1bfd325cb2a5c98ba87f94ad upstream. struct vhost_msg within struct vhost_msg_node is copied to userspace. Unfortunately it turns out on 64 bit systems vhost_msg has padding after type which gcc doesn't initialize, leaking 4 uninitialized bytes to userspace. This padding also unfortunately means 32 bit users of this interface are broken on a 64 bit kernel which will need to be fixed separately. Fixes: CVE-2018-1118 Cc: stable@vger.kernel.org Reported-by: Kevin Easton Signed-off-by: Michael S. Tsirkin Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vhost.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2382,6 +2382,9 @@ struct vhost_msg_node *vhost_new_msg(str 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;