From 37aa50c539bcbcc01767e515bd170787fcfc0f33 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 9 Feb 2022 03:19:55 -0500 Subject: [PATCH 1/2] vlan: introduce vlan_dev_free_egress_priority This patch is to introduce vlan_dev_free_egress_priority() to free egress priority for vlan dev, and keep vlan_dev_uninit() static as .ndo_uninit. It makes the code more clear and safer when adding new code in vlan_dev_uninit() in the future. Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/8021q/vlan.h | 2 +- net/8021q/vlan_dev.c | 7 ++++++- net/8021q/vlan_netlink.c | 7 ++++--- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h index 1a705a4ef7fa8..5eaf38875554b 100644 --- a/net/8021q/vlan.h +++ b/net/8021q/vlan.h @@ -129,6 +129,7 @@ void vlan_dev_set_ingress_priority(const struct net_device *dev, u32 skb_prio, u16 vlan_prio); int vlan_dev_set_egress_priority(const struct net_device *dev, u32 skb_prio, u16 vlan_prio); +void vlan_dev_free_egress_priority(const struct net_device *dev); int vlan_dev_change_flags(const struct net_device *dev, u32 flag, u32 mask); void vlan_dev_get_realdev_name(const struct net_device *dev, char *result, size_t size); @@ -139,7 +140,6 @@ int vlan_check_real_dev(struct net_device *real_dev, void vlan_setup(struct net_device *dev); int register_vlan_dev(struct net_device *dev, struct netlink_ext_ack *extack); void unregister_vlan_dev(struct net_device *dev, struct list_head *head); -void vlan_dev_uninit(struct net_device *dev); bool vlan_dev_inherit_address(struct net_device *dev, struct net_device *real_dev); diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index 26d031a43cc1a..e5d23e75572a0 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -622,7 +622,7 @@ static int vlan_dev_init(struct net_device *dev) } /* Note: this function might be called multiple times for the same device. */ -void vlan_dev_uninit(struct net_device *dev) +void vlan_dev_free_egress_priority(const struct net_device *dev) { struct vlan_priority_tci_mapping *pm; struct vlan_dev_priv *vlan = vlan_dev_priv(dev); @@ -636,6 +636,11 @@ void vlan_dev_uninit(struct net_device *dev) } } +static void vlan_dev_uninit(struct net_device *dev) +{ + vlan_dev_free_egress_priority(dev); +} + static netdev_features_t vlan_dev_fix_features(struct net_device *dev, netdev_features_t features) { diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c index 0db85aeb119b8..53b1955b027f8 100644 --- a/net/8021q/vlan_netlink.c +++ b/net/8021q/vlan_netlink.c @@ -183,10 +183,11 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev, return -EINVAL; err = vlan_changelink(dev, tb, data, extack); - if (!err) - err = register_vlan_dev(dev, extack); if (err) - vlan_dev_uninit(dev); + return err; + err = register_vlan_dev(dev, extack); + if (err) + vlan_dev_free_egress_priority(dev); return err; } From d6ff94afd90b0ce8d1715f8ef77d4347d7a7f2c0 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 9 Feb 2022 03:19:56 -0500 Subject: [PATCH 2/2] 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 Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/8021q/vlan_dev.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index e5d23e75572a0..d1902828a18aa 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)