CVE-2022-50881 — wifi: ath9k: Fix use-after-free in ath9k_hif_usb_disconnect()

Affected: Linux

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

wifi: ath9k: Fix use-after-free in ath9k_hif_usb_disconnect()

This patch fixes a use-after-free in ath9k that occurs in ath9k_hif_usb_disconnect() when ath9k_destroy_wmi() is trying to access 'drv_priv' that has already been freed by ieee80211_free_hw(), called by ath9k_htc_hw_deinit(). The patch moves ath9k_destroy_wmi() before ieee80211_free_hw(). Note that urbs from the driver should be killed before freeing 'wmi' with ath9k_destroy_wmi() as their callbacks will access 'wmi'.

Found by a modified version of syzkaller.

================================================================== BUG: KASAN: use-after-free in ath9k_destroy_wmi+0x38/0x40 Read of size 8 at addr ffff8881069132a0 by task kworker/0:1/7

CPU: 0 PID: 7 Comm: kworker/0:1 Tainted: G O 5.14.0+ #131 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Workqueue: usb_hub_wq hub_event Call Trace: dump_stack_lvl+0x8e/0xd1 print_address_description.constprop.0.cold+0x93/0x334 ? ath9k_destroy_wmi+0x38/0x40 ? ath9k_destroy_wmi+0x38/0x40 kasan_report.cold+0x83/0xdf ? ath9k_destroy_wmi+0x38/0x40 ath9k_destroy_wmi+0x38/0x40 ath9k_hif_usb_disconnect+0x329/0x3f0 ? ath9k_hif_usb_suspend+0x120/0x120 ? usb_disable_interface+0xfc/0x180 usb_unbind_interface+0x19b/0x7e0 ? usb_autoresume_device+0x50/0x50 device_release_driver_internal+0x44d/0x520 bus_remove_device+0x2e5/0x5a0 device_…

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CVE-2022-50881 — wifi: ath9k: Fix use-after-free in ath9k_hif_usb_disconnect()