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| author | Xin Long <lucien.xin@gmail.com> | 2022-02-09 11:19:56 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-02-09 16:33:39 +0300 |
| commit | d6ff94afd90b0ce8d1715f8ef77d4347d7a7f2c0 (patch) | |
| tree | 735fa70930e02744565c7791bd8e0bb3bda7f26a /net/8021q | |
| parent | 37aa50c539bcbcc01767e515bd170787fcfc0f33 (diff) | |
| download | linux-d6ff94afd90b0ce8d1715f8ef77d4347d7a7f2c0.tar.xz | |
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 563bcbae3ba2 ("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: 563bcbae3ba2 ("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>
Diffstat (limited to 'net/8021q')
| -rw-r--r-- | net/8021q/vlan_dev.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index e5d23e75572a..d1902828a18a 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -638,7 +638,12 @@ void vlan_dev_free_egress_priority(const struct net_device *dev) static void vlan_dev_uninit(struct net_device *dev) { + struct vlan_dev_priv *vlan = vlan_dev_priv(dev); + vlan_dev_free_egress_priority(dev); + + /* Get rid of the vlan's reference to real_dev */ + dev_put_track(vlan->real_dev, &vlan->dev_tracker); } static netdev_features_t vlan_dev_fix_features(struct net_device *dev, @@ -851,9 +856,6 @@ static void vlan_dev_free(struct net_device *dev) free_percpu(vlan->vlan_pcpu_stats); vlan->vlan_pcpu_stats = NULL; - - /* Get rid of the vlan's reference to real_dev */ - dev_put_track(vlan->real_dev, &vlan->dev_tracker); } void vlan_setup(struct net_device *dev) |