CVE-2024-40911: NULL Pointer Dereference

In the Linux kernel, the following vulnerability has been resolved:

wifi: cfg80211: Lock wiphy in cfg80211_get_station

Wiphy should be locked before calling rdev_get_station() (see lockdep assert in ieee80211_get_station()).

This fixes the following kernel NULL dereference:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 Mem abort info: ESR = 0x0000000096000006 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x06: level 2 translation fault Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=0000000003001000 [0000000000000050] pgd=0800000002dca003, p4d=0800000002dca003, pud=08000000028e9003, pmd=0000000000000000 Internal error: Oops: 0000000096000006 [#1] SMP Modules linked in: netconsole dwc3_meson_g12a dwc3_of_simple dwc3 ip_gre gre ath10k_pci ath10k_core ath9k ath9k_common ath9k_hw ath CPU: 0 PID: 1091 Comm: kworker/u8:0 Not tainted 6.4.0-02144-g565f9a3a7911-dirty #705 Hardware name: RPT (r1) (DT) Workqueue: bat_events batadv_v_elp_throughput_metric_update pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : ath10k_sta_statistics+0x10/0x2dc [ath10k_core] lr : sta_set_sinfo+0xcc/0xbd4 sp : ffff000007b43ad0 x29: ffff000007b43ad0 x28: ffff0000071fa900 x27: ffff00000294ca98 x26: ffff000006830880 x25: ffff000006830880 x24: ffff00000294c000 x23: 0000000000000001 x22: ffff000007b43c90 x21: ffff800008898acc x20: ffff00000294c6e8 x19: ffff000007b43c90 x18: 0000000000000000 x17: 445946354d552d78 x16: 62661f7200000000 x15: 57464f445946354d x14: 0000000000000000 x13: 00000000000000e3 x12: d5f0acbcebea978e x11: 00000000000000e3 x10: 000000010048fe41 x9 : 0000000000000000 x8 : ffff000007b43d90 x7 : 000000007a1e2125 x6 : 0000000000000000 x5 : ffff0000024e0900 x4 : ffff800000a0250c x3 : ffff000007b43c90 x2 : ffff00000294ca98 x1 : ffff000006831920 x0 : 0000000000000000 Call trace: ath10k_sta_statistics+0x10/0x2dc [ath10k_core] sta_set_sinfo+0xcc/0xbd4 ieee80211_get_station+0x2c/0x44 cfg80211_get_station+0x80/0x154 batadv_v_elp_get_throughput+0x138/0x1fc batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x1ec/0x414 worker_thread+0x70/0x46c kthread+0xdc/0xe0 ret_from_fork+0x10/0x20 Code: a9bb7bfd 910003fd a90153f3 f9411c40 (f9402814)

This happens because STA has time to disconnect and reconnect before batadv_v_elp_throughput_metric_update() delayed work gets scheduled. In this situation, ath10k_sta_state() can be in the middle of resetting arsta data when the work queue get chance to be scheduled and ends up accessing it. Locking wiphy prevents that.