vhost: do not try to access device IOTLB when not initialized

The code will try to access dev->iotlb when processing
VHOST_IOTLB_INVALIDATE even if it was not initialized which may lead
to NULL pointer dereference. Fixes this by check dev->iotlb before.

Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 549771a0cd8b90d087034823c6404412658839c0..5727b186b3ca56b6d43249bc69eb7f962bd22308 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1015,6 +1015,10 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
                vhost_iotlb_notify_vq(dev, msg);
                break;
        case VHOST_IOTLB_INVALIDATE:
+               if (!dev->iotlb) {
+                       ret = -EFAULT;
+                       break;
+               }
                vhost_vq_meta_reset(dev);
                vhost_del_umem_range(dev->iotlb, msg->iova,
                                     msg->iova + msg->size - 1);