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authorXin Long <lucien.xin@gmail.com>2022-02-09 03:19:56 -0500
committerDavid S. Miller <davem@davemloft.net>2022-02-09 13:33:39 +0000
commitd6ff94afd90b0ce8d1715f8ef77d4347d7a7f2c0 (patch)
tree735fa70930e02744565c7791bd8e0bb3bda7f26a /net/8021q
parent37aa50c539bcbcc01767e515bd170787fcfc0f33 (diff)
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.c8
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)