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From: Prasad J Pandit <pjp@fedoraproject.org>
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Date: Wed, 29 Nov 2017 23:14:27 +0530
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Subject: [PATCH] virtio: check VirtQueue Vring object is set
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A guest could attempt to use an uninitialised VirtQueue object
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or unset Vring.align leading to a arithmetic exception. Add check
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to avoid it.
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Reported-by: Zhangboxian <zhangboxian@huawei.com>
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Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Cornelia Huck <cohuck@redhat.com>
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(cherry picked from commit 758ead31c7e17bf17a9ef2e0ca1c3e86ab296b43)
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---
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hw/virtio/virtio.c | 14 +++++++++++---
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1 file changed, 11 insertions(+), 3 deletions(-)
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diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
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index 15cf6021a0..138fd0e936 100644
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--- a/hw/virtio/virtio.c
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+++ b/hw/virtio/virtio.c
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@@ -182,7 +182,7 @@ void virtio_queue_update_rings(VirtIODevice *vdev, int n)
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{
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VRing *vring = &vdev->vq[n].vring;
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- if (!vring->desc) {
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+ if (!vring->num || !vring->desc || !vring->align) {
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/* not yet setup -> nothing to do */
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return;
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}
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@@ -1416,6 +1416,9 @@ void virtio_config_modern_writel(VirtIODevice *vdev,
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void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
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{
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+ if (!vdev->vq[n].vring.num) {
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+ return;
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+ }
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vdev->vq[n].vring.desc = addr;
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virtio_queue_update_rings(vdev, n);
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}
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@@ -1428,6 +1431,9 @@ hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
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void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
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hwaddr avail, hwaddr used)
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{
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+ if (!vdev->vq[n].vring.num) {
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+ return;
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+ }
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vdev->vq[n].vring.desc = desc;
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vdev->vq[n].vring.avail = avail;
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vdev->vq[n].vring.used = used;
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@@ -1496,8 +1502,10 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
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*/
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assert(k->has_variable_vring_alignment);
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- vdev->vq[n].vring.align = align;
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- virtio_queue_update_rings(vdev, n);
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+ if (align) {
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+ vdev->vq[n].vring.align = align;
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+ virtio_queue_update_rings(vdev, n);
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+ }
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}
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static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
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