kernel/linux.git/drivers/hid/hid-multitouch.c, branch v5.10.264

HID: multitouch: fix out-of-bounds bit access on mt_io_flags

2026-07-24T13:49:21+00:00

[ Upstream commit 8813b0612275cc61fe9e6603d0ee019247ade6be ] mt_io_flags is a single unsigned long, but mt_process_slot(), mt_release_pending_palms() and mt_release_contacts() use it as a per-slot bitmap indexed by the slot number. That slot number is only bounded by td->maxcontacts, which is taken from the device's ContactCountMaximum feature report and can be up to 255, not by BITS_PER_LONG. As a result, a multitouch device that advertises a large contact count makes set_bit()/clear_bit() operate past the mt_io_flags word and corrupt the adjacent members of struct mt_device. The sticky-fingers release timer is the easiest way to reach this. mt_release_contacts() runs for (i = 0; i < mt->num_slots; i++) clear_bit(i, &td->mt_io_flags); with num_slots == maxcontacts. For maxcontacts around 250 the loop clears the bits that overlap td->applications.next, zeroing that list head, and the list_for_each_entry() that immediately follows then dereferences NULL. The kernel panics from timer (softirq) context. On a KASAN build this shows up as a general protection fault in mt_release_contacts() with a null-ptr-deref at offset 0x58, which is offsetof(struct mt_application, num_received). The state is reachable from an untrusted USB or Bluetooth HID multitouch device; no local privileges are required. Store the per-slot active state in a separately allocated bitmap sized for maxcontacts, the same pattern already used for pending_palm_slots, and keep only MT_IO_FLAGS_RUNNING in mt_io_flags. The two "mt_io_flags & MT_IO_SLOTS_MASK" arming checks become bitmap_empty(td->active_slots, td->maxcontacts). Move MT_IO_FLAGS_RUNNING back to bit 0. It was bumped to bit 32 by the same commit to leave the low byte for the slot bits; with the slot bits gone it fits in bit 0 again, which also keeps it within the unsigned long on 32-bit. Fixes: 46f781e0d151 ("HID: multitouch: fix sticky fingers") Cc: stable@vger.kernel.org Signed-off-by: Trung Nguyen Signed-off-by: Benjamin Tissoires Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

HID: pass the buffer size to hid_report_raw_event

2026-06-19T11:21:33+00:00

[ Upstream commit 2c85c61d1332e1e16f020d76951baf167dcb6f7a ] commit 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing bogus memset()") enforced the provided data to be at least the size of the declared buffer in the report descriptor to prevent a buffer overflow. However, we can try to be smarter by providing both the buffer size and the data size, meaning that hid_report_raw_event() can make better decision whether we should plaining reject the buffer (buffer overflow attempt) or if we can safely memset it to 0 and pass it to the rest of the stack. Fixes: 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing bogus memset()") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Tissoires Acked-by: Johan Hovold Reviewed-by: Greg Kroah-Hartman Signed-off-by: Jiri Kosina Stable-dep-of: 206342541fc8 ("HID: core: introduce hid_safe_input_report()") Signed-off-by: Sasha Levin (cherry picked from commit 509c2605065004fc4cd86ee50a9350d402785307) [Lee: Backported to linux-6.12.y and beyond] Signed-off-by: Lee Jones (cherry picked from commit f9393998660f146970047bda31526aeb96190f28) Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

HID: multitouch: Check to ensure report responses match the request

2026-04-18T08:31:08+00:00

[ Upstream commit e716edafedad4952fe3a4a273d2e039a84e8681a ] It is possible for a malicious (or clumsy) device to respond to a specific report's feature request using a completely different report ID. This can cause confusion in the HID core resulting in nasty side-effects such as OOB writes. Add a check to ensure that the report ID in the response, matches the one that was requested. If it doesn't, omit reporting the raw event and return early. Signed-off-by: Lee Jones Signed-off-by: Benjamin Tissoires Signed-off-by: Sasha Levin

HID: multitouch: add eGalaxTouch EXC3188 support

2026-03-04T12:19:59+00:00

[ Upstream commit 8e4ac86b2ddd36fe501e20ecfcc080e536df1f48 ] Add support for the for the EXC3188 touchscreen from eGalaxy. Signed-off-by: Thorsten Schmelzer Signed-off-by: Michael Tretter Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin

HID: multitouch: add MT_QUIRK_STICKY_FINGERS to MT_CLS_VTL

2026-02-11T12:34:22+00:00

[ Upstream commit ff3f234ff1dcd6d626a989151db067a1b7f0f215 ] Some VTL-class touchpads (e.g. TOPS0102:00 35CC:0104) intermittently fail to release a finger contact. A previous slot remains logically active, accompanied by stale BTN_TOOL_DOUBLETAP state, causing gestures to stay latched and resulting in stuck two-finger scrolling and false right-clicks. Apply MT_QUIRK_STICKY_FINGERS to handle the unreleased contact correctly. Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/1225 Suggested-by: Benjamin Tissoires Tested-by: DaytonCL Signed-off-by: DaytonCL Signed-off-by: Benjamin Tissoires Signed-off-by: Sasha Levin

HID: multitouch: fix sticky fingers

2025-10-29T13:01:18+00:00

commit 46f781e0d151844589dc2125c8cce3300546f92a upstream. The sticky fingers quirk (MT_QUIRK_STICKY_FINGERS) was only considering the case when slots were not released during the last report. This can be problematic if the firmware forgets to release a finger while others are still present. This was observed on the Synaptics DLL0945 touchpad found on the Dell XPS 9310 and the Dell Inspiron 5406. Fixes: 4f4001bc76fd ("HID: multitouch: fix rare Win 8 cases when the touch up event gets missing") Cc: stable@vger.kernel.org Signed-off-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman

HID: multitouch: Add NULL check in mt_input_configured

2025-03-13T11:47:14+00:00

[ Upstream commit 9b8e2220d3a052a690b1d1b23019673e612494c5 ] devm_kasprintf() can return a NULL pointer on failure,but this returned value in mt_input_configured() is not checked. Add NULL check in mt_input_configured(), to handle kernel NULL pointer dereference error. Fixes: 479439463529 ("HID: multitouch: Correct devm device reference for hidinput input_dev name") Signed-off-by: Charles Han Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin

HID: multitouch: Add quirk for HONOR MagicBook Art 14 touchpad

2024-11-17T13:59:39+00:00

[ Upstream commit 7a5ab8071114344f62a8b1e64ed3452a77257d76 ] The behavior of HONOR MagicBook Art 14 touchpad is not consistent after reboots, as sometimes it reports itself as a touchpad, and sometimes as a mouse. Similarly to GLO-GXXX it is possible to call MT_QUIRK_FORCE_GET_FEATURE as a workaround to force set feature in mt_set_input_mode() for such special touchpad device. [jkosina@suse.com: reword changelog a little bit] Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/1040 Signed-off-by: Wentao Guan Signed-off-by: WangYuli Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin

HID: Add quirk for Logitech Casa touchpad

2024-07-05T07:12:35+00:00

[ Upstream commit dd2c345a94cfa3873cc20db87387ee509c345c1b ] This device sometimes doesn't send touch release signals when moving from >=4 fingers to <4 fingers. Using MT_QUIRK_NOT_SEEN_MEANS_UP instead of MT_QUIRK_ALWAYS_VALID makes sure that no touches become stuck. MT_QUIRK_FORCE_MULTI_INPUT is not necessary for this device, but does no harm. Signed-off-by: Sean O'Brien Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin

HID: multitouch: Add required quirk for Synaptics 0xcddc device

2024-03-26T22:21:46+00:00

[ Upstream commit 1741a8269e1c51fa08d4bfdf34667387a6eb10ec ] Add support for the pointing stick (Accupoint) and 2 mouse buttons. Present on some Toshiba/dynabook Portege X30 and X40 laptops. It should close https://bugzilla.kernel.org/show_bug.cgi?id=205817 Signed-off-by: Manuel Fombuena Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin