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virtio: check VirtQueue Vring object is set

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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 <zhangboxian@huawei.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Prasad J Pandit 2017-11-29 23:14:27 +05:30 • committed by Michael S. Tsirkin
parent 2fe45ec3bf
commit 758ead31c7
1 changed files with 11 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

10
hw/virtio/virtio.c
View file

@ -182,7 +182,7 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
{ {
VRing *vring = &vdev->vq[n].vring; VRing *vring = &vdev->vq[n].vring;
if (!vring->desc) { if (!vring->num || !vring->desc || !vring->align) {
/* not yet setup -> nothing to do */ /* not yet setup -> nothing to do */
return; return;
} }
@ -1414,6 +1414,9 @@ void virtio_config_modern_writel(VirtIODevice *vdev,
void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr) void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
{ {
if (!vdev->vq[n].vring.num) {
return;
}
vdev->vq[n].vring.desc = addr; vdev->vq[n].vring.desc = addr;
virtio_queue_update_rings(vdev, n); 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, void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
hwaddr avail, hwaddr used) hwaddr avail, hwaddr used)
{ {
if (!vdev->vq[n].vring.num) {
return;
}
vdev->vq[n].vring.desc = desc; vdev->vq[n].vring.desc = desc;
vdev->vq[n].vring.avail = avail; vdev->vq[n].vring.avail = avail;
vdev->vq[n].vring.used = used; 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); assert(k->has_variable_vring_alignment);
if (align) {
vdev->vq[n].vring.align = align; vdev->vq[n].vring.align = align;
virtio_queue_update_rings(vdev, n); virtio_queue_update_rings(vdev, n);
}
} }
static bool virtio_queue_notify_aio_vq(VirtQueue *vq) static bool virtio_queue_notify_aio_vq(VirtQueue *vq)