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

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
(oxp_set_buttons()/oxp_gen_2_property_out() -> hid_hw_output_report(),
each followed by msleep(200)). oxp_hid_remove() cancels it with the
non-synchronising cancel_delayed_work(), so a worker already running is
not waited for; removing the device while the worker is asleep then frees
the hid_device underneath it, leaving drvdata.hdev stale -- a
use-after-free when the worker wakes.

The oxp_rgb_queue and oxp_btn_queue workers, wired up the same way and
also cancelled with cancel_delayed_work() in oxp_hid_remove(), have the
same problem.

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@vger.kernel.org
Signed-off-by: Shengzhuo Wei <redacted>
---
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. The fix mirrors the cancel_delayed_work_sync()
approach already used by hid-lenovo-go / hid-lenovo-go-s.
---
 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);