Messages in this thread Patch in this message | | | From | Dexuan Cui <> | Subject | [PATCH] netvsc: fix use-after-free in netvsc_change_mtu() | Date | Thu, 2 Mar 2017 13:00:53 +0000 |
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'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> --- drivers/net/hyperv/netvsc_drv.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 2d3cdb0..bc05c89 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -859,15 +859,22 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu) if (ret) goto out; + 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; - 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; rndis_filter_device_add(hdev, &device_info); out: -- 2.7.4
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