netvsc: fix use-after-free in netvsc_change_mtu()

'nvdev' is freed in rndis_filter_device_remove -> netvsc_device_remove ->
free_netvsc_device, so we mustn't access it, before it's re-created in
rndis_filter_device_add -> netvsc_device_add.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dexuan Cui 2017-03-02 13:00:53 +00:00 committed by David S. Miller
parent 35576ee17f
commit 152669bd3c

View File

@ -859,15 +859,22 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
if (ret)
goto out;
ndevctx->start_remove = true;
rndis_filter_device_remove(hdev, nvdev);
ndev->mtu = mtu;
memset(&device_info, 0, sizeof(device_info));
device_info.ring_size = ring_size;
device_info.num_chn = nvdev->num_chn;
device_info.max_num_vrss_chns = nvdev->num_chn;
ndevctx->start_remove = true;
rndis_filter_device_remove(hdev, nvdev);
/* 'nvdev' has been freed in rndis_filter_device_remove() ->
* netvsc_device_remove () -> free_netvsc_device().
* We mustn't access it before it's re-created in
* rndis_filter_device_add() -> netvsc_device_add().
*/
ndev->mtu = mtu;
rndis_filter_device_add(hdev, &device_info);
out: