CVE-2026-64363
Description
In the Linux kernel, the following vulnerability has been resolved:
HID: appleir: fix UAF on pending key_up_timer in remove()
appleir_remove() runs hid_hw_stop() before timer_delete_sync().
hid_hw_stop() synchronously unregisters the HID input device via
hid_disconnect() -> hidinput_disconnect() -> input_unregister_device(),
which drops the last reference and frees the underlying input_dev when
no userspace handle holds it open.
key_up_tick() reads appleir->input_dev and calls input_report_key() /
input_sync() on it. The timer is armed from appleir_raw_event() with
a HZ/8 (~125 ms) timeout on every keydown and key-repeat report. If a
key was pressed shortly before the device is disconnected, the timer
can fire after hid_hw_stop() has freed input_dev but before the
teardown drains it.
A simple reorder is not sufficient. Putting the timer drain first
still leaves a window where a USB URB completion (raw_event) running
during hid_hw_stop() can call mod_timer() and re-arm the timer, which
then fires after hidinput_disconnect() has freed input_dev. The same
URB-completion window also lets raw_event() reach key_up(), key_down()
and battery_flat() directly, all of which dereference
appleir->input_dev.
Introduce a 'removing' flag on struct appleir, gated by the existing
spinlock. appleir_remove() sets the flag under the lock and then
shuts down the timer with timer_shutdown_sync(), which both drains any
in-flight callback and permanently disables further mod_timer() calls.
appleir_raw_event() and key_up_tick() bail out early if the flag is
set, so no path can arm or run the timer, or dereference
appleir->input_dev, after remove() has started tearing down.
The keyrepeat and flatbattery branches of appleir_raw_event()
previously called into the input layer without holding the spinlock;
take it now so the flag check is well-defined. This incidentally
closes a pre-existing read-side race on appleir->current_key in the
keyrepeat branch.
This bug is structurally a sibling of commit 4db2af929279 ("HID:
appletb-kbd: fix UAF in inactivity-timer cleanup path") and has been
present since the driver was introduced.
Metadata
Severity & Metrics
No CVSS data available.
Affected products (2)
| Vendor | Product | Platform | Versions |
|---|---|---|---|
| Linux | Linux | — | 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e < 89ef67359672bf4cd6921524e39f61648fe38c0f, 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e < 3d30a0bb0e79621ae921b487835c56198adfafa3, 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e < 37a52c61d4f78153c38ae1f7491dfcc8ac828dcf, 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e < 05e3decc55d1deca9410e0eb36466651fcbe57a5 … |
| Linux | Linux | — | 3.10, 0 < 3.10, 5.10.261 ≤ 5.10.*, 5.15.212 ≤ 5.15.* … |
References (8)
- https://git.kernel.org/stable/c/89ef67359672bf4cd6921524e39f61648fe38c0f
- https://git.kernel.org/stable/c/3d30a0bb0e79621ae921b487835c56198adfafa3
- https://git.kernel.org/stable/c/37a52c61d4f78153c38ae1f7491dfcc8ac828dcf
- https://git.kernel.org/stable/c/05e3decc55d1deca9410e0eb36466651fcbe57a5
- https://git.kernel.org/stable/c/3755f6e25776b8b12ddf062f9b573f05090e4034
- https://git.kernel.org/stable/c/b363d964ca829c1761c9f04188dfa28f90b0f2d4
- https://git.kernel.org/stable/c/6b0838e86da88b1d3bff86f19761ff25af73eaca
- https://git.kernel.org/stable/c/75fe87e19d8aff81eb2c64d15d244ab8da4de945