From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46734 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932736AbeDJWkV (ORCPT ); Tue, 10 Apr 2018 18:40:21 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+6304bf97ef436580fede@syzkaller.appspotmail.com, Jason Wang , "Michael S. Tsirkin" , "David S. Miller" Subject: [PATCH 4.14 134/138] vhost: validate log when IOTLB is enabled Date: Wed, 11 Apr 2018 00:25:24 +0200 Message-Id: <20180410212917.818627954@linuxfoundation.org> In-Reply-To: <20180410212902.121524696@linuxfoundation.org> References: <20180410212902.121524696@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: Jason Wang [ Upstream commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ] Vq log_base is the userspace address of bitmap which has nothing to do with IOTLB. So it needs to be validated unconditionally otherwise we may try use 0 as log_base which may lead to pin pages that will lead unexpected result (e.g trigger BUG_ON() in set_bit_to_user()). Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API") Reported-by: syzbot+6304bf97ef436580fede@syzkaller.appspotmail.com Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vhost.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1252,14 +1252,12 @@ static int vq_log_access_ok(struct vhost /* Caller should have vq mutex and device mutex */ int vhost_vq_access_ok(struct vhost_virtqueue *vq) { - if (vq->iotlb) { - /* When device IOTLB was used, the access validation - * will be validated during prefetching. - */ - return 1; - } - return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used) && - vq_log_access_ok(vq, vq->log_base); + int ret = vq_log_access_ok(vq, vq->log_base); + + if (ret || vq->iotlb) + return ret; + + return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); } EXPORT_SYMBOL_GPL(vhost_vq_access_ok);