| Upstream-Status: Backport |
| |
| Supplementary fix of CVE-2016-5403 which is backported from: |
| |
| http://git.qemu.org/?p=qemu.git;a=commit;h=4b7f91e |
| |
| Signed-off-by: Kai Kang <kai.kang@windriver.com> |
| --- |
| From 4b7f91ed0270a371e1933efa21ba600b6da23ab9 Mon Sep 17 00:00:00 2001 |
| From: Stefan Hajnoczi <stefanha@redhat.com> |
| Date: Wed, 7 Sep 2016 11:51:25 -0400 |
| Subject: [PATCH] virtio: zero vq->inuse in virtio_reset() |
| |
| vq->inuse must be zeroed upon device reset like most other virtqueue |
| fields. |
| |
| In theory, virtio_reset() just needs assert(vq->inuse == 0) since |
| devices must clean up in-flight requests during reset (requests cannot |
| not be leaked!). |
| |
| In practice, it is difficult to achieve vq->inuse == 0 across reset |
| because balloon, blk, 9p, etc implement various different strategies for |
| cleaning up requests. Most devices call g_free(elem) directly without |
| telling virtio.c that the VirtQueueElement is cleaned up. Therefore |
| vq->inuse is not decremented during reset. |
| |
| This patch zeroes vq->inuse and trusts that devices are not leaking |
| VirtQueueElements across reset. |
| |
| I will send a follow-up series that refactors request life-cycle across |
| all devices and converts vq->inuse = 0 into assert(vq->inuse == 0) but |
| this more invasive approach is not appropriate for stable trees. |
| |
| Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> |
| Cc: qemu-stable <qemu-stable@nongnu.org> |
| Reviewed-by: Michael S. Tsirkin <mst@redhat.com> |
| Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
| Reviewed-by: Ladi Prosek <lprosek@redhat.com> |
| --- |
| hw/virtio/virtio.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c |
| index 74c085c..e8a13a5 100644 |
| --- a/hw/virtio/virtio.c |
| +++ b/hw/virtio/virtio.c |
| @@ -822,6 +822,7 @@ void virtio_reset(void *opaque) |
| vdev->vq[i].signalled_used_valid = false; |
| vdev->vq[i].notification = true; |
| vdev->vq[i].vring.num = vdev->vq[i].vring.num_default; |
| + vdev->vq[i].inuse = 0; |
| } |
| } |
| |
| -- |
| 2.9.3 |
| |