Ziyang Xuan 5e44178864 net: vlan: fix underflow for the real_dev refcnt ... [ Upstream commit 01d9cc2dea ] Inject error before dev_hold(real_dev) in register_vlan_dev(), and execute the following testcase: ip link add dev dummy1 type dummy ip link add name dummy1.100 link dummy1 type vlan id 100 ip link del dev dummy1 When the dummy netdevice is removed, we will get a WARNING as following: ======================================================================= refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 and an endless loop of: ======================================================================= unregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824 That is because dev_put(real_dev) in vlan_dev_free() be called without dev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev underflow. Move the dev_hold(real_dev) to vlan_dev_init() which is the call-back of ndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev symmetrical. Fixes: 563bcbae3b ("net: vlan: fix a UAF in vlan_dev_real_dev()") Reported-by: Petr Machata <petrm@nvidia.com> Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Link: https://lore.kernel.org/r/20211126015942.2918542-1-william.xuanziyang@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-12-01 09:23:34 +01:00
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Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	net: remove blank lines at end of file	2018-07-24 14:10:43 -07:00
vlan.c	net: vlan: fix underflow for the real_dev refcnt	2021-12-01 09:23:34 +01:00
vlan.h	vlan: fix memory leak in vlan_dev_set_egress_priority	2020-01-12 12:21:49 +01:00
vlan_core.c	net: 8021q: move vlan offload registrations into vlan_core	2018-11-16 19:51:08 -08:00
vlan_dev.c	net: vlan: fix underflow for the real_dev refcnt	2021-12-01 09:23:34 +01:00
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: vlan_changelink() should propagate errors	2020-01-12 12:21:50 +01:00
vlanproc.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
vlanproc.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00