In the Linux kernel, the following vulnerability has been resolved:
mac802154: hold an interface reference across the scan worker
mac802154_scan_worker() captures the scanning sub-interface under RCU and then keeps dereferencing sdata->dev after rcu_read_unlock() and outside the rtnl – in the failure traces, in mac802154_transmit_beacon_req() (skb->dev = sdata->dev), and in the end_scan cleanup. Nothing keeps that netdev alive across the worker iteration.
A concurrent DEL_INTERFACE or PHY removal can unregister the interface once the worker drops the rtnl between its two drv_set_channel() sections. unregister_netdevice() frees the netdev asynchronously from netdev_run_todo() with the rtnl already dropped, so neither holding the rtnl nor the per-PHY IEEE802154_IS_SCANNING flag prevents a stale worker iteration from dereferencing the freed netdev – a KASAN slab-use-after-free, reachable by racing TRIGGER_SCAN against DEL_INTERFACE (both CAP_NET_ADMIN).
Pin the netdev with netdev_hold() while the RCU read lock is still held, and release it at every worker exit.
References
- https://git.kernel.org/stable/c/234e5e898b713bc0b3a631b6f002897f43d046c8
- https://git.kernel.org/stable/c/59c1d5463b7bc5a2cdaae27108d1dfd67edc7d1b
- https://git.kernel.org/stable/c/5f303f622f6bb8907c405e5123a0ab0f70fb0065
- https://git.kernel.org/stable/c/bd7110f0caa32426140ff302a209c53294ef2cfd
- https://git.kernel.org/stable/c/dd4754194a706163294b6141460101b99082c8c7