Messages in this thread Patch in this message | | | From | Jason Wang <> | Subject | [PATCH 3/3] caif_virtio: fix the race between reset and netdev unregister | Date | Mon, 20 Jun 2022 13:11:15 +0800 |
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We use to do the following steps during .remove():
static void cfv_remove(struct virtio_device *vdev) { struct cfv_info *cfv = vdev->priv;
rtnl_lock(); dev_close(cfv->ndev); rtnl_unlock();
tasklet_kill(&cfv->tx_release_tasklet); debugfs_remove_recursive(cfv->debugfs);
vringh_kiov_cleanup(&cfv->ctx.riov); virtio_reset_device(vdev); vdev->vringh_config->del_vrhs(cfv->vdev); cfv->vr_rx = NULL; vdev->config->del_vqs(cfv->vdev); unregister_netdev(cfv->ndev); }
This is racy since device could be re-opened after dev_close() but before unregister_netdevice():
1) RX vringh is cleaned before resetting the device, rx callbacks that is called after the vringh_kiov_cleanup() will result a UAF 2) Network stack can still try to use TX virtqueue even if it has been deleted after dev_vqs()
Fixing this by unregistering the network device first to make sure not device access from both TX and RX side.
Fixes: 0d2e1a2926b18 ("caif_virtio: Introduce caif over virtio") Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/caif/caif_virtio.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/net/caif/caif_virtio.c b/drivers/net/caif/caif_virtio.c index 66375bea2fcd..a29f9b2df5b1 100644 --- a/drivers/net/caif/caif_virtio.c +++ b/drivers/net/caif/caif_virtio.c @@ -752,9 +752,8 @@ static void cfv_remove(struct virtio_device *vdev) { struct cfv_info *cfv = vdev->priv; - rtnl_lock(); - dev_close(cfv->ndev); - rtnl_unlock(); + /* Make sure NAPI/TX won't try to access the device */ + unregister_netdev(cfv->ndev); tasklet_kill(&cfv->tx_release_tasklet); debugfs_remove_recursive(cfv->debugfs); @@ -764,7 +763,6 @@ static void cfv_remove(struct virtio_device *vdev) vdev->vringh_config->del_vrhs(cfv->vdev); cfv->vr_rx = NULL; vdev->config->del_vqs(cfv->vdev); - unregister_netdev(cfv->ndev); } static struct virtio_device_id id_table[] = { -- 2.25.1
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