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linux-stable/net/8021q
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Xin Long d6ff94afd9 vlan: move dev_put into vlan_dev_uninit 
Shuang Li reported an QinQ issue by simply doing:

  # ip link add dummy0 type dummy
  # ip link add link dummy0 name dummy0.1 type vlan id 1
  # ip link add link dummy0.1 name dummy0.1.2 type vlan id 2
  # rmmod 8021q

 unregister_netdevice: waiting for dummy0.1 to become free. Usage count = 1

When rmmods 8021q, all vlan devs are deleted from their real_dev's vlan grp
and added into list_kill by unregister_vlan_dev(). dummy0.1 is unregistered
before dummy0.1.2, as it's using for_each_netdev() in __rtnl_kill_links().

When unregisters dummy0.1, dummy0.1.2 is not unregistered in the event of
NETDEV_UNREGISTER, as it's been deleted from dummy0.1's vlan grp. However,
due to dummy0.1.2 still holding dummy0.1, dummy0.1 will keep waiting in
netdev_wait_allrefs(), while dummy0.1.2 will never get unregistered and
release dummy0.1, as it delays dev_put until calling dev->priv_destructor,
vlan_dev_free().

This issue was introduced by Commit 563bcbae3b ("net: vlan: fix a UAF in
vlan_dev_real_dev()"), and this patch is to fix it by moving dev_put() into
vlan_dev_uninit(), which is called after NETDEV_UNREGISTER event but before
netdev_wait_allrefs().

Fixes: 563bcbae3b ("net: vlan: fix a UAF in vlan_dev_real_dev()")
Reported-by: Shuang Li <shuali@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 13:33:39 +00:00
..
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile
vlan.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-11-26 13:45:19 -08:00
vlan.h vlan: introduce vlan_dev_free_egress_priority 2022-02-09 13:33:39 +00:00
vlan_core.c gro: remove rcu_read_lock/rcu_read_unlock from gro_complete handlers 2021-11-24 17:21:42 -08:00
vlan_dev.c vlan: move dev_put into vlan_dev_uninit 2022-02-09 13:33:39 +00:00
vlan_gvrp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vlan_mvrp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vlan_netlink.c vlan: introduce vlan_dev_free_egress_priority 2022-02-09 13:33:39 +00:00
vlanproc.c net: remove .ndo_change_proto_down 2021-11-23 12:18:48 +00:00
vlanproc.h