CVE-2026-80766: HID: uclogic: fix use-after-free of inrange_timer on remove

CVE-2026-80766: HID: uclogic: fix use-after-free of inrange_timer on remove

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

HID: uclogic: fix use-after-free of inrange_timer on remove

uclogic_remove() cancels the pen in-range timer and then stops the
device:

	timer_delete_sync(&drvdata->inrange_timer);
	hid_hw_stop(hdev);

timer_delete_sync() only guarantees the timer is idle at that instant.
uclogic_raw_event_pen() keeps delivering pen reports until hid_hw_stop()
stops the transport several lines later, and every report with
pen->inrange == UCLOGIC_PARAMS_PEN_INRANGE_NONE re-arms the timer:

	mod_timer(&drvdata->inrange_timer, jiffies + msecs_to_jiffies(100));

A report landing between the timer_delete_sync() call and the transport
teardown in hid_hw_stop() re-arms inrange_timer after it was cancelled.
uclogic_remove() then returns and the devm drvdata is freed, while
hid_hw_stop() has already freed the input device drvdata->pen_input
points at, so when the timer fires ~100 ms later
uclogic_inrange_timeout() dereferences freed memory -- a use-after-free
in timer-softirq context.

Swapping the two calls is not a fix: stopping the device first frees
drvdata->pen_input via hidinput_disconnect() while the timer may still
be pending, so a timer already armed before removal fires on the freed
input device in the window before timer_delete_sync() runs.

Use timer_shutdown_sync() before hid_hw_stop() instead. It cancels the
timer, waits for a running callback while pen_input is still valid, and
prevents any further re-arming -- a later mod_timer() from an in-flight
report is silently ignored -- so the timer is provably dead before
hid_hw_stop() frees the inputs. This is the ordering the timer core
documents for this "timer re-armed from another path" teardown case.

The Linux kernel CVE team has assigned CVE-2026-80766 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 5.15.220 with commit f40243358b407aec362fe305fabfcdc94a3abd89
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 6.1.187 with commit dc5108f18f58870a8dd4203a02a47e571a2be7f0
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 6.6.156 with commit 9d77ac82e57ead056cf3f71d347083ed9244ad90
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 6.12.108 with commit e750cdb6de009aace3c77f37fe2173f96175e8e4
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 6.18.47 with commit 849e537160bbb77fe419ecc3944bfe125dcd441b
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 7.1.11 with commit f1b3ca06380531f49f988f4721d3ed30b0d7a5d2
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 7.2.1 with commit f13d0a00204b05e62336da0ab72ea0d87b56690c
	Issue introduced in 5.1 with commit 01309e29eb95c16bd48984f2589fad0cbf5e27d1 and fixed in 7.3-rc1 with commit 506fd50a9027340f0e9dcc587d10ccb03312dba6

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-80766
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/hid/hid-uclogic-core.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f40243358b407aec362fe305fabfcdc94a3abd89
	https://git.kernel.org/stable/c/dc5108f18f58870a8dd4203a02a47e571a2be7f0
	https://git.kernel.org/stable/c/9d77ac82e57ead056cf3f71d347083ed9244ad90
	https://git.kernel.org/stable/c/e750cdb6de009aace3c77f37fe2173f96175e8e4
	https://git.kernel.org/stable/c/849e537160bbb77fe419ecc3944bfe125dcd441b
	https://git.kernel.org/stable/c/f1b3ca06380531f49f988f4721d3ed30b0d7a5d2
	https://git.kernel.org/stable/c/f13d0a00204b05e62336da0ab72ea0d87b56690c
	https://git.kernel.org/stable/c/506fd50a9027340f0e9dcc587d10ccb03312dba6