From 9e0f5b8108e248b78444c9a2ec41a8309825736c Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 12 Mar 2015 17:50:18 +0800 Subject: [PATCH] virtio: validate the existence of handle_output before calling it We don't validate the existence of handle_output which may let a buggy guest to trigger a SIGSEV easily. E.g: 1) write 10 to queue_sel to a virtio net device with only 1 queue 2) setup an arbitrary pfn 3) then notify queue 10 Fixing this by validating the existence of handle_output before. Cc: qemu-stable@nongnu.org Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Don Koch Reviewed-by: Fam Zheng --- hw/virtio/virtio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 3c6e430048..17c1260c0d 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -759,8 +759,9 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align) void virtio_queue_notify_vq(VirtQueue *vq) { - if (vq->vring.desc) { + if (vq->vring.desc && vq->handle_output) { VirtIODevice *vdev = vq->vdev; + trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); vq->handle_output(vdev, vq); } -- GitLab