FAILED: patch "[PATCH] HID: sony: fix UAF of ghl_poke_timer / ghl_urb at driver" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x a26705bd2e2728833e7a538ce91e58a5eeff496a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090334-elevation-quill-589f@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a26705bd2e2728833e7a538ce91e58a5eeff496a Mon Sep 17 00:00:00 2001
From: Doruk Tan Ozturk <[email protected]>
Date: Fri, 24 Jul 2026 16:27:03 +0200
Subject: [PATCH] HID: sony: fix UAF of ghl_poke_timer / ghl_urb at driver
unbind

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.

index 5a7ab08cb825..52d156e1db39 100644
@@ -2424,7 +2424,9 @@ static void sony_remove(struct hid_device *hdev)
 	struct sony_sc *sc = hid_get_drvdata(hdev);
 
 	if (sc->quirks & (GHL_GUITAR_PS3WIIU | GHL_GUITAR_PS4)) {
-		timer_delete_sync(&sc->ghl_poke_timer);
+		/* poison, not kill: a pending timer must not re-submit during teardown */
+		usb_poison_urb(sc->ghl_urb);
+		timer_shutdown_sync(&sc->ghl_poke_timer);
 		usb_free_urb(sc->ghl_urb);
 	}
 

From: Doruk Tan Ozturk <[email protected]>

[ Upstream commit a26705bd2e2728833e7a538ce91e58a5eeff496a ]

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.

---
 drivers/hid/hid-sony.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index c330d5a20ca04..b4858304c18da 100644
@@ -3085,7 +3085,9 @@ static void sony_remove(struct hid_device *hdev)
 	struct sony_sc *sc = hid_get_drvdata(hdev);
 
 	if (sc->quirks & (GHL_GUITAR_PS3WIIU | GHL_GUITAR_PS4)) {
-		del_timer_sync(&sc->ghl_poke_timer);
+		/* poison, not kill: a pending timer must not re-submit during teardown */
+		usb_poison_urb(sc->ghl_urb);
+		timer_shutdown_sync(&sc->ghl_poke_timer);
 		usb_free_urb(sc->ghl_urb);
 	}
 

2.53.0