From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKooA-0000xN-Aq for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:09:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKoo9-0007AF-Bd for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:09:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35012) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eKoo9-00079c-4v for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:09:01 -0500 Date: Fri, 1 Dec 2017 19:08:53 +0200 From: "Michael S. Tsirkin" Message-ID: <1512148088-28733-7-git-send-email-mst@redhat.com> References: <1512148088-28733-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1512148088-28733-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 6/7] virtio: check VirtQueue Vring object is set List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Prasad J Pandit , Zhangboxian , Stefan Hajnoczi , Cornelia Huck From: Prasad J Pandit A guest could attempt to use an uninitialised VirtQueue object or unset Vring.align leading to a arithmetic exception. Add check to avoid it. Reported-by: Zhangboxian Signed-off-by: Prasad J Pandit Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi Reviewed-by: Cornelia Huck --- hw/virtio/virtio.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 703e672..ad564b0 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -182,7 +182,7 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n) { VRing *vring = &vdev->vq[n].vring; - if (!vring->desc) { + if (!vring->num || !vring->desc || !vring->align) { /* not yet setup -> nothing to do */ return; } @@ -1414,6 +1414,9 @@ void virtio_config_modern_writel(VirtIODevice *vdev, void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr) { + if (!vdev->vq[n].vring.num) { + return; + } vdev->vq[n].vring.desc = addr; virtio_queue_update_rings(vdev, n); } @@ -1426,6 +1429,9 @@ hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n) void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc, hwaddr avail, hwaddr used) { + if (!vdev->vq[n].vring.num) { + return; + } vdev->vq[n].vring.desc = desc; vdev->vq[n].vring.avail = avail; vdev->vq[n].vring.used = used; @@ -1494,8 +1500,10 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align) */ assert(k->has_variable_vring_alignment); - vdev->vq[n].vring.align = align; - virtio_queue_update_rings(vdev, n); + if (align) { + vdev->vq[n].vring.align = align; + virtio_queue_update_rings(vdev, n); + } } static bool virtio_queue_notify_aio_vq(VirtQueue *vq) -- MST