From: Ziyang Xuan william.xuanziyang@huawei.com
[ Upstream commit 563bcbae3ba233c275c244bfce2efe12938f5363 ]
The real_dev of a vlan net_device may be freed after unregister_vlan_dev(). Access the real_dev continually by vlan_dev_real_dev() will trigger the UAF problem for the real_dev like following:
================================================================== BUG: KASAN: use-after-free in vlan_dev_real_dev+0xf9/0x120 Call Trace: kasan_report.cold+0x83/0xdf vlan_dev_real_dev+0xf9/0x120 is_eth_port_of_netdev_filter.part.0+0xb1/0x2c0 is_eth_port_of_netdev_filter+0x28/0x40 ib_enum_roce_netdev+0x1a3/0x300 ib_enum_all_roce_netdevs+0xc7/0x140 netdevice_event_work_handler+0x9d/0x210 ...
Freed by task 9288: kasan_save_stack+0x1b/0x40 kasan_set_track+0x1c/0x30 kasan_set_free_info+0x20/0x30 __kasan_slab_free+0xfc/0x130 slab_free_freelist_hook+0xdd/0x240 kfree+0xe4/0x690 kvfree+0x42/0x50 device_release+0x9f/0x240 kobject_put+0x1c8/0x530 put_device+0x1b/0x30 free_netdev+0x370/0x540 ppp_destroy_interface+0x313/0x3d0 ...
Move the put_device(real_dev) to vlan_dev_free(). Ensure real_dev not be freed before vlan_dev unregistered.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+e4df4e1389e28972e955@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/8021q/vlan.c | 3 --- net/8021q/vlan_dev.c | 3 +++ 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index 4cdf8416869d1..e31f6be98b75b 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -123,9 +123,6 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head) }
vlan_vid_del(real_dev, vlan->vlan_proto, vlan_id); - - /* Get rid of the vlan's reference to real_dev */ - dev_put(real_dev); }
int vlan_check_real_dev(struct net_device *real_dev, diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c index a0367b37512d8..c34685774b573 100644 --- a/net/8021q/vlan_dev.c +++ b/net/8021q/vlan_dev.c @@ -843,6 +843,9 @@ 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(vlan->real_dev); }
void vlan_setup(struct net_device *dev)