Re: [PATCH v2] HID: sony: fix UAF of ghl_poke_timer / ghl_urb at driver unbind

On Fri, 24 Jul 2026, Doruk Tan Ozturk wrote:

> For GHL (Guitar Hero Live) dongles, sony_probe() arms a periodic timer:
> ghl_magic_poke() (the timer callback) submits sc->ghl_urb, and the URB
> completion ghl_magic_poke_cb() re-arms the timer with mod_timer().
> 
> sony_remove() drained the timer with timer_delete_sync() and then freed
> the URB with usb_free_urb():
> 
> 	timer_delete_sync(&sc->ghl_poke_timer);
> 	usb_free_urb(sc->ghl_urb);
> 
> timer_delete_sync() does not block re-arming, and while the URB is in
> flight the timer is not pending, so the sync delete is a no-op. A URB
> completion that runs after the delete re-arms the timer, and usb_free_urb()
> only drops a reference -- it does not kill an in-flight URB. sc is
> allocated with devm_kzalloc() and freed once sony_remove() returns, so the
> re-armed ghl_poke_timer (embedded in sc) then fires on freed memory, a
> use-after-free from timer softirq. This is a disconnect/rmmod race.
> 
> Poison the URB first, then shut the timer down, before freeing the URB.
> usb_poison_urb() kills any in-flight URB and permanently rejects further
> submissions, so a poke timer that is still pending cannot re-submit the
> URB from ghl_magic_poke() in the window before timer_shutdown_sync() runs.
> usb_kill_urb() would not suffice: it only cancels the in-flight URB and
> leaves it submittable once it returns, so the pending timer could
> re-submit it and put a fresh URB in flight over the freed sc.
> timer_shutdown_sync() then drains any last callback and blocks re-arming.
> The probe error path is unaffected: it is only reached before the timer
> is armed.
> 
> Reproduced under KASAN on next-20260710 via dummy_hcd + raw-gadget
> emulation of the GHL PS4 dongle (VID 0x1430 / PID 0x07bb): hid-sony binds
> and arms the poke timer, the poke URB is held in flight, the driver is
> unbound (freeing sc), then the URB is released. The completion re-arms the
> timer on the freed sc, and the re-armed timer fires ~8 s later:
> 
>   BUG: KASAN: slab-use-after-free in ghl_magic_poke+0x98/0xb0
>   Read of size 8 at addr ffff88810b02fd50 by task swapper/0/0
>    ghl_magic_poke+0x98/0xb0
>    call_timer_fn+0x35/0x2b0
>    __run_timers+0x69c/0x9a0
>    run_timer_softirq+0x173/0x2a0
>   Allocated by task 169:  sony_probe
>   Freed by task 338:      devres_release_group <- hid_device_remove (sony_remove)
> 
> Found by 0sec (https://0sec.ai) using automated source analysis.
> 
> Fixes: cc894ac55360 ("HID: sony: support for ghlive ps3/wii u dongles")
> Cc: [email protected]
> Assisted-by: 0sec:multi-model
> Signed-off-by: Doruk Tan Ozturk <[email protected]>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs