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Re: [Qemu-devel] [PATCH v1 1/2] virtio: check VirtQueue Vring object is
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [PATCH v1 1/2] virtio: check VirtQueue Vring object is set |
Date: |
Fri, 24 Nov 2017 10:01:14 +0100 |
On Fri, 24 Nov 2017 13:25:41 +0530
P J P <address@hidden> wrote:
> From: Prasad J Pandit <address@hidden>
>
> An user 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 <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
> hw/virtio/virtio.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> Updated: add vring.num check to virtio_queue_update_rings
> -> https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg04499.html
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 5884ce3480..0940f1daf3 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 (!vdev->vq[n].vring.num || !vring->desc || !vring->align) {
> /* not yet setup -> nothing to do */
The check now implies "not yet setup or non-existing queue", no?
(Not that the check is wrong.)
> 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);
> }
> @@ -1494,8 +1497,10 @@ 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)
I think you also need to check for num in virtio_queue_set_rings().