CVE-2026-80780: HID: pidff: fix OOB write when hid->inputs is empty

CVE-2026-80780: HID: pidff: fix OOB write when hid->inputs is empty

[Greg Kroah-Hartman]

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

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

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

HID: pidff: fix OOB write when hid->inputs is empty

hid_pidff_init_with_quirks() derives its input_dev from

	list_entry(hid->inputs.next, struct hid_input, list)

without first checking that hid->inputs is non-empty.  The list member
of struct hid_input is at offset 0, so on an empty list list_entry()
yields &hid->inputs itself and the following hidinput->input load reads
an unrelated member of struct hid_device.  dev is then a type-confused
pointer, and force-feedback init writes through it: each
set_bit(FF_*, dev->ffbit) stores 8 bytes at dev + 192, past the end of
the object dev actually aliases, and input_ff_create() adds further
writes of a heap pointer and two function pointers.

Until hid-universal-pidff the only caller was hid_pidff_init() from
usbhid, which runs under HID_CLAIMED_INPUT and therefore always has at
least one hid_input.  universal_pidff_probe() starts the device with
HID_CONNECT_DEFAULT & ~HID_CONNECT_FF and then calls
hid_pidff_init_with_quirks() directly whenever the descriptor carries a
PID usage page, bypassing that gate.  A report descriptor whose only
application collection is on HID_UP_PID leaves hid->inputs empty while
hid_connect() still succeeds through the hidraw claim, so probe reaches
the unguarded list_entry().

The write happens in the USB probe path, on the hotplug workqueue, so
plugging in a malicious device is enough to trigger it; no attacker
software and no logged-in user are required.  KASAN reports an 8-byte
out-of-bounds write in hid_pidff_init_with_quirks() reached from
universal_pidff_probe().

Check for an empty list before deriving dev and return -ENODEV, as the
other HID force-feedback drivers already do.  universal_pidff_probe()
propagates the error and unwinds.

Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

The Linux kernel CVE team has assigned CVE-2026-80780 to this issue.


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

	Issue introduced in 6.6.88 with commit c1fde337b317f0a226de92803288741c30799eb0 and fixed in 6.6.156 with commit 2e0471bf3ab2a6b7eedcc3b8a2a17286b6a9ae1a
	Issue introduced in 6.12.24 with commit f45f26a6b3e7260c129c7c6bb0ace63aeb7b3868 and fixed in 6.12.108 with commit ad9330f7e74a97842815a291a0d7389ed2f34504
	Issue introduced in 6.15 with commit f06bf8d94fffbb544b1cb5402c92e0a075f0d420 and fixed in 6.18.47 with commit 4529c03c3da8f91392cd630453452f569973f4cd
	Issue introduced in 6.15 with commit f06bf8d94fffbb544b1cb5402c92e0a075f0d420 and fixed in 7.1.11 with commit d416eeb7d016d82af67c149d884bc6a9323c4ac7
	Issue introduced in 6.15 with commit f06bf8d94fffbb544b1cb5402c92e0a075f0d420 and fixed in 7.2.1 with commit 86b63adfa5e132beac4be72668fdf9128fe51d2e
	Issue introduced in 6.15 with commit f06bf8d94fffbb544b1cb5402c92e0a075f0d420 and fixed in 7.3-rc1 with commit 67bb1074e3d2d12fa059a9cc707e89398a4e4704
	Issue introduced in 6.13.12 with commit af9f2471dfe5a48384f5b7f021a673fbc741465e
	Issue introduced in 6.14.3 with commit b797352954eee6dc084cfaed0659dea60adfb484

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-2026-80780
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/usbhid/hid-pidff.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/2e0471bf3ab2a6b7eedcc3b8a2a17286b6a9ae1a
	https://git.kernel.org/stable/c/ad9330f7e74a97842815a291a0d7389ed2f34504
	https://git.kernel.org/stable/c/4529c03c3da8f91392cd630453452f569973f4cd
	https://git.kernel.org/stable/c/d416eeb7d016d82af67c149d884bc6a9323c4ac7
	https://git.kernel.org/stable/c/86b63adfa5e132beac4be72668fdf9128fe51d2e
	https://git.kernel.org/stable/c/67bb1074e3d2d12fa059a9cc707e89398a4e4704