vlan: fix a use-after-free in vlan_device_event()
After refcnt reaches zero, vlan_vid_del() could free dev->vlan_info via RCU: RCU_INIT_POINTER(dev->vlan_info, NULL); call_rcu(&vlan_info->rcu, vlan_info_rcu_free); However, the pointer 'grp' still points to that memory since it is set before vlan_vid_del(): vlan_info = rtnl_dereference(dev->vlan_info); if (!vlan_info) goto out; grp = &vlan_info->grp; Depends on when that RCU callback is scheduled, we could trigger a use-after-free in vlan_group_for_each_dev() right following this vlan_vid_del(). Fix it by moving vlan_vid_del() before setting grp. This is also symmetric to the vlan_vid_add() we call in vlan_device_event(). Reported-by:Fengguang Wu <fengguang.wu@intel.com> Fixes: efc73f4b ("net: Fix memory leak - vlan_info struct") Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Girish Moodalbail <girish.moodalbail@oracle.com> Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by:
Girish Moodalbail <girish.moodalbail@oracle.com> Tested-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
2118df93
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