[PATCH v3] HID: hid-oxp: fix UAF on pending work in remove()

[Shengzhuo Wei]

oxp_cfg_probe() arms drvdata.oxp_mcu_init to run 50 ms after probe, and
oxp_mcu_init_fn() dereferences drvdata.hdev to issue MCU output reports
(hid_hw_output_report() followed by msleep(200)). The oxp_rgb_queue and
oxp_btn_queue workers are wired up the same way. oxp_hid_remove()
cancels all three with the non-synchronising cancel_delayed_work(), so a
worker already running is not waited for; removing the device while a
worker is asleep then frees the hid_device underneath it, leaving
drvdata.hdev stale -- a use-after-free when the worker wakes.

Drain all three works with cancel_delayed_work_sync() in oxp_hid_remove()
so they have exited before the hid_device is freed.

Fixes: 84910c459d65 ("HID: hid-oxp: Add OneXPlayer configuration driver")
Fixes: e4c850a6e750 ("HID: hid-oxp: Add Button Mapping Interface")
Fixes: 2f424f28fb39 ("HID: hid-oxp: Add Second Generation Gamepad Mode Switch")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Shengzhuo Wei <me@xxxxxxxx>
---
Same delayed-work use-after-free class as the 7.2-rc6 sweep
(hid-lenovo-go, hid-lenovo-go-s, hid-lg-g15, hid-appleir, hid-letsketch);
hid-oxp was missed.
---
Changes in v3:
- Revert to cancel_delayed_work_sync() and drop v2's probe-change
  reordering: with the driver's static global drvdata,
  disable_delayed_work_sync() would permanently disable the works when
  any interface of the device is unbound (Derek J. Clark). The re-arm
  hardening and the per-device drvdata rework will be handled separately
  by the driver maintainer.
- Link to v2: https://lore.kernel.org/r/20260804-oxp-fix-v2-1-b2d56e4c8a2c@xxxxxxxx

Changes in v2:
- Use disable_delayed_work_sync() instead of cancel_delayed_work_sync()
  so the works cannot be re-armed (e.g. via oxp_rgb_brightness_set())
  while the device is being torn down (Dmitry Torokhov).
- Arm oxp_mcu_init only after devm_device_add_group() succeeds, so a
  probe failure can no longer leave it pending to fire on a freed
  hid device (sashiko).
- Link to v1: https://lore.kernel.org/r/20260804-oxp-fix-v1-1-51a4fe787167@xxxxxxxx
---
 drivers/hid/hid-oxp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-oxp.c b/drivers/hid/hid-oxp.c
index 20a54f337220dc2aee3483a14d542b66c487bd60..d8fb6a69d40d43f2595179df1067d42b4b3e166a 100644
--- a/drivers/hid/hid-oxp.c
+++ b/drivers/hid/hid-oxp.c
@@ -1552,9 +1552,9 @@ static int oxp_hid_probe(struct hid_device *hdev,
 
 static void oxp_hid_remove(struct hid_device *hdev)
 {
-	cancel_delayed_work(&drvdata.oxp_rgb_queue);
-	cancel_delayed_work(&drvdata.oxp_btn_queue);
-	cancel_delayed_work(&drvdata.oxp_mcu_init);
+	cancel_delayed_work_sync(&drvdata.oxp_rgb_queue);
+	cancel_delayed_work_sync(&drvdata.oxp_btn_queue);
+	cancel_delayed_work_sync(&drvdata.oxp_mcu_init);
 	hid_hw_close(hdev);
 	hid_hw_stop(hdev);
 }

---
base-commit: 075b74841bd0065a3bda3440873c747938e69b68
change-id: 20260804-oxp-fix-879390c5e47f

Best regards,
-- 
Shengzhuo Wei <me@xxxxxxxx>