From: Xuanqiang Luo <[email protected]>
ieee802154_unregister_hw() unregisters the wpan netdevs before
destroying mac_wq. The RX path stores the receiving sub-interface
(sdata) in the queued MAC command descriptor without taking a
reference to the netdev.
If mac802154_rx_mac_cmd_worker() runs after the netdev has been freed,
it dereferences the stale pointer and triggers a KASAN
slab-use-after-free:
BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0xc0/0x498
[mac802154]
Read of size 8 at addr ffff0000c6db0ba8 by task kworker/u16:3/61
...
Call trace:
show_stack+0x20/0x38 (C)
dump_stack_lvl+0x78/0x90
print_address_description.constprop.0+0x88/0x398
print_report+0xa8/0x278
kasan_report+0xa8/0xf8
__asan_load8+0x9c/0xc0
mac802154_rx_mac_cmd_worker+0xc0/0x498 [mac802154]
process_one_work+0x334/0x8b8
...
Allocated by task 630:
kasan_save_stack+0x2c/0x58
kasan_save_track+0x20/0x40
kasan_save_alloc_info+0x40/0x58
__kasan_kmalloc+0xa0/0xb8
__kvmalloc_node_noprof+0x1e8/0x588
alloc_netdev_mqs+0x74/0x7f0
ieee802154_if_add+0xac/0x630 [mac802154]
ieee802154_register_hw+0x31c/0x3d0 [mac802154]
fakelb_add_one+0x250/0x318 [fakelb]
...
Freed by task 652:
kasan_save_stack+0x2c/0x58
kasan_save_track+0x20/0x40
kasan_save_free_info+0x4c/0x78
__kasan_slab_free+0x60/0x90
kfree+0x194/0x478
kvfree+0x44/0x60
netdev_release+0x4c/0x68
device_release+0xac/0x130
kobject_cleanup+0x84/0x248
kobject_put+0x98/0xf8
netdev_run_todo+0x3a0/0x5e0
rtnl_unlock+0x18/0x30
ieee802154_unregister_hw+0x48/0x90 [mac802154]
fakelb_remove+0xe8/0x148 [fakelb]
After killing local->tasklet, drain mac_wq before calling
ieee802154_remove_interfaces() so pending work completes before the
interfaces are unregistered. Do this without holding rtnl because scan
and beacon workers acquire it themselves.
Fixes: d021d218f6d9 ("mac802154: Handle received BEACON_REQ")
Signed-off-by: Xuanqiang Luo <[email protected]>
---
net/mac802154/main.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/mac802154/main.c b/net/mac802154/main.c
index ea1efef3572ae..dc80184d7d091 100644
--- a/net/mac802154/main.c
+++ b/net/mac802154/main.c
@@ -276,6 +276,11 @@ void ieee802154_unregister_hw(struct ieee802154_hw *hw)
tasklet_kill(&local->tasklet);
flush_workqueue(local->workqueue);
+ /*
+ * Drain mac_wq before unregistering interfaces; some workers access
+ * sub-interface data and acquire rtnl themselves.
+ */
+ drain_workqueue(local->mac_wq);
rtnl_lock();
--
2.43.0
