linux-stable.git/drivers/input/touchscreen, branch linux-rolling-lts

Input: sur40 - fix V4L error path cleanup

2026-08-23T12:26:58+00:00

commit 062dc4693e2c10d77de06f61e6f3faf37c0a8383 upstream.

In sur40_probe(), if video_register_device() fails, the error path jumps to
err_unreg_video. This incorrectly attempts to unregister a video device
that was never successfully registered, and fails to free the V4L2 control
handler (v4l2_ctrl_handler_free) that was initialized immediately prior.

Fix this by introducing an err_free_ctrl label to properly free the V4L2
control handler and bypass video_unregister_device() when video device
registration fails.

Reported-by: sashiko-bot@kernel.org
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Link: https://patch.msgid.link/20260616051235.1549517-2-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: sur40 - fix input device registration ordering

2026-08-23T12:26:58+00:00

commit 9da976eb649c9e2f588a4499410e4d8af687925f upstream.

In sur40_probe(), input_register_device() was previously called early before
the V4L2 video device and vb2_queue components were fully initialized. If
userspace opened the input device immediately upon registration, sur40_open()
would trigger and start the sur40_poll() worker thread. This worker thread
invokes sur40_process_video() and accesses the uninitialized vb2_queue
structure, leading to a data race and potential system crash.

Furthermore, if V4L2 or video registration failed after input_register_device()
succeeded, the error path fell through to calling input_free_device() on a
successfully registered device instead of input_unregister_device(), corrupting
input core state.

Move input_register_device() to the very end of sur40_probe(). This ensures
the V4L2 and video queue structures are fully initialized before polling can
start, and naturally resolves the error path bug since input_free_device()
is now only called when input registration has not yet occurred.

To maintain strict LIFO (Last-In, First-Out) teardown ordering, also move
input_unregister_device() to the very beginning of sur40_disconnect(). This
guarantees that the input polling worker thread is stopped before V4L2
video components or control handlers are unregistered.

Reported-by: sashiko-bot@kernel.org
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Link: https://patch.msgid.link/20260616051235.1549517-1-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: hynitron_cstxxx - validate touch count and finger IDs

2026-08-23T12:26:57+00:00

commit 27f380ef0e1d3de3cde114e02d33f9320ce3a5a6 upstream.

The driver allocates max_touch_num input slots, which are indexed from
zero through max_touch_num - 1. The current check allows a finger ID
equal to max_touch_num to reach cst3xx_report_contact(). While the input
core ignores out-of-range slot indices, reporting touch data without a
valid slot change corrupts the touch state of the previously active slot.

The touch count is read from the controller's report and is used to
index the fixed-size report buffer without first checking its range.
Reject counts larger than the supported number of touch slots before
checking the trailing byte or parsing touch data.

Reject finger IDs equal to or greater than max_touch_num, and return
immediately when an invalid finger ID is encountered so that corrupt
touch frames are discarded instead of reporting partial contact state.

The V821 Avaota F1 board configures the vendor driver with one touch
slot, so finger ID 1 is already invalid on that device.

Fixes: 66603243f528 ("Input: add driver for Hynitron cstxxx touchscreens")
Signed-off-by: Jianing Li 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260804031339.2379-1-m13940358460@163.com
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: mms114 - fix multi-touch slot corruption

2026-07-18T14:53:35+00:00

commit adea84ee6cdea611146c4251d3c1616f5a09feca upstream.

If the touchscreen controller reports a touch ID of 0, the driver
calculates the slot ID as touch->id - 1, which underflows to UINT_MAX.
This is passed to input_mt_slot() as -1.

Since the input core ignores negative slot values, the active slot remains
unchanged. The driver then reports the touch coordinates for the previously
active slot, corrupting its state.

Fix this by rejecting touch reports with ID 0.

Fixes: 07b8481d4aff ("Input: add MELFAS mms114 touchscreen driver")
Cc: stable@vger.kernel.org
Reported-by: sashiko-bot@kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Link: https://patch.msgid.link/20260704060115.353049-1-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: mms114 - reject an oversized device packet size

2026-07-18T14:53:35+00:00

commit 66725039f7090afe14c31bd259e2059a68f04023 upstream.

mms114_interrupt() reads a packet of touch data from the device into a
fixed-size on-stack buffer

	struct mms114_touch touch[MMS114_MAX_TOUCH];

which holds MMS114_MAX_TOUCH (10) events of MMS114_EVENT_SIZE (8) bytes,
i.e. 80 bytes. The length of the I2C read into it is taken verbatim from
the device:

	packet_size = mms114_read_reg(data, MMS114_PACKET_SIZE);
	if (packet_size <= 0)
		goto out;
	...
	error = __mms114_read_reg(data, MMS114_INFORMATION, packet_size,
			(u8 *)touch);

packet_size is a single device register byte (0x0F) and the only check
is the lower bound packet_size <= 0; it is never bounded against the
size of touch[]. A malfunctioning, malicious or counterfeit controller
(or an attacker tampering with the I2C bus) can report a packet_size of
up to 255, so __mms114_read_reg() writes up to 175 bytes past the end of
touch[] on the IRQ-thread stack: a stack out-of-bounds write that can
overwrite the stack canary, saved registers and the return address.

A well-formed device never reports more than the buffer holds, so reject
an oversized packet and drop the report, consistent with the handler's
other error paths, rather than reading past the buffer.

Fixes: 07b8481d4aff ("Input: add MELFAS mms114 touchscreen driver")
Signed-off-by: Bryam Vargas 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260612-b4-disp-dc4b8dc4-v1-1-d7cb0a828d92@proton.me
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: touchwin - reset the packet index on every complete packet

2026-07-18T14:53:34+00:00

commit 478cdd736f2ce3114f90e775d7358136d3977b94 upstream.

tw_interrupt() accumulates each non-zero serial byte into a fixed
three-byte buffer with a running index that is only reset once a full
packet has been received *and* the device's two Y bytes agree:

	tw->data[tw->idx++] = data;
	if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) {
		...
		tw->idx = 0;
	}

The reset is gated on tw->data[1] == tw->data[2], a value the device
controls.  A malicious, malfunctioning or counterfeit Touchwindow
peripheral can stream non-zero bytes whose 2nd and 3rd bytes differ: the
index reaches TW_LENGTH without the equality holding, is never reset, and
keeps growing, so tw->data[tw->idx++] walks off the end of the three-byte
array and the rest of the heap-allocated struct tw, one attacker-chosen
byte at a time -- an unbounded, device-driven heap out-of-bounds write.

Reset the index on every completed packet and report an event only when
the two Y bytes match, like the other serio touchscreen drivers do.

Fixes: 11ea3173d5f2 ("Input: add driver for Touchwin serial touchscreens")
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas 
Link: https://patch.msgid.link/20260613-b4-disp-69921bfd-v1-1-82c036899959@proton.me
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: ads7846 - don't use scratch for tx_buf when clearing register

2026-07-18T14:53:34+00:00

commit 856668312685d9a8f32d49a135a89c429d309f81 upstream.

The workaround for XPT2046 clears the command register, giving the
touchscreen controller a NOP. The change incorrectly re-uses the
req->scratch variable which is used as rx_buf for xfer[5], so by
the time xfer[6] occurs, the contents of req->scratch may not be
0. It was found that the touchscreen controller can end up in
a completely unresponsive state due to it being given a command
the driver does not expect.

Instead, rely on the spi_transfer behavior of tx_buf being NULL to
transmit all 0 bits and use the scratch variable for the rx_buf for
both the 1 byte command to and 2 byte response from the controller.

Also relocates the scratch member of struct ser_req to force it
into a different cache line to prevent any potential issues of
DMA stepping on unrelated data in other struct members due to
sharing the same cache line.

This change was tested on real TSC2046 and ADS7843 controllers,
but not the XPT2046 the workaround was originally created for.
Confirming that the original modification to clear the command
register does not impact either real controller.

Fixes: 781a07da9bb94 ("Input: ads7846 - add dummy command register clearing cycle")
Cc: stable@vger.kernel.org
Co-developed-by: Mark Featherston 
Signed-off-by: Mark Featherston 
Signed-off-by: Kris Bahnsen 
Link: https://patch.msgid.link/20260507164943.760009-1-kris@embeddedTS.com
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: mms114 - fix touch indexing for MMS134S and MMS136

2026-07-18T14:53:34+00:00

commit a6ac4e24c1a8a533bb61035184fdcc7eede4cc8d upstream.

The MMS134S and MMS136 touch controllers have an event size of 6 bytes
rather than 8 bytes. When __mms114_read_reg() reads the touch data
packet from the device into the touch buffer, the events are packed
tightly at 6-byte intervals. However, the driver iterates through the
events using standard C array indexing (touch[index]), where each
element is sizeof(struct mms114_touch) (8 bytes) apart. As a result, any
touch events beyond the first one are read from incorrect offsets and
parsed improperly.

Fix this by explicitly calculating the byte offset for each touch event
based on the device's specific event size.

Fixes: 53fefdd1d3a3 ("Input: mms114 - support MMS136")
Fixes: ab108678195f ("Input: mms114 - support MMS134S")
Reported-by: sashiko-bot@kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Reviewed-by: Bryam Vargas 
Link: https://patch.msgid.link/20260616050912.1531241-1-dmitry.torokhov@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: goodix - clamp the device-reported contact count

2026-07-18T14:53:34+00:00

commit 5ed62a96e06be4e94b8296b7932afee550a70e04 upstream.

goodix_ts_read_input_report() copies the number of touch points reported
by the device into an on-stack buffer

	u8 point_data[2 + GOODIX_MAX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];

which is sized for at most GOODIX_MAX_CONTACTS (10) contacts. The only
runtime check bounds the per-interrupt count against ts->max_touch_num,
but that value is taken verbatim from a 4-bit field of the device
configuration block and is never clamped:

	ts->max_touch_num = ts->config[MAX_CONTACTS_LOC] & 0x0f;

The nibble can be 0..15, so a malfunctioning, malicious or counterfeit
controller (or an attacker tampering with the I2C bus) can advertise up
to 15 contacts. goodix_ts_read_input_report() then accepts a touch_num
of up to 15 and the second goodix_i2c_read() writes
ts->contact_size * (touch_num - 1) bytes past the one-contact header into
point_data - up to 30 bytes (45 with the 9-byte report format) beyond the
92-byte buffer: a stack out-of-bounds write.

Clamp max_touch_num to GOODIX_MAX_CONTACTS, the number of contacts
point_data[] is sized for, when reading it from the configuration.

Fixes: a7ac7c95d468 ("Input: goodix - use max touch number from device config")
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas 
Reviewed-by: Hans de Goede 
Link: https://patch.msgid.link/20260612-b4-disp-6844625d-v1-1-df0aed080c9d@proton.me
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

Input: atmel_mxt_ts - fix boundary check in mxt_prepare_cfg_mem

2026-06-09T10:28:42+00:00

commit baa0210fb6a9dc3882509a9411b6d284d88fe30e upstream.

When a configuration file provides an object size that is larger than the
driver's known mxt_obj_size(object), the driver intends to discard the
extra bytes.

The loop iterates using for (i = 0; i < size; i++). Inside the loop, the
condition to skip processing extra bytes is:

    if (i > mxt_obj_size(object))
        continue;

Since i is a 0-based index, the valid indices for the object are 0 through
mxt_obj_size(object) - 1.

When i == mxt_obj_size(object), the condition evaluates to false, and the
code processes the byte instead of discarding it.

This causes the code to calculate byte_offset = reg + i - cfg->start_ofs
and writes the byte there, overwriting exactly one byte of the adjacent
instance or object.

Update the boundary check to skip extra bytes correctly by using >=.

Fixes: 50a77c658b80 ("Input: atmel_mxt_ts - download device config using firmware loader")
Cc: stable@vger.kernel.org
Assisted-by: Gemini:gemini-3.1-pro
Reviewed-by: Ricardo Ribalda 
Link: https://patch.msgid.link/20260504185448.4055973-1-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman