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authorDexuan Cui <decui@microsoft.com>2017-03-02 13:00:53 +0000
committerDavid S. Miller <davem@davemloft.net>2017-03-02 14:41:36 -0800
commit152669bd3cd2407d6f556009b95ee249c0c1a462 (patch)
treedc032a0eb328b1d4e81224a2d640c67543221201
parent35576ee17f7c15a5ec776570088fd2eff1dbdc2d (diff)
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>
-rw-r--r--drivers/net/hyperv/netvsc_drv.c15
1 files 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: