CVE-2026-89620: HID: intel-thc-hid: intel-quickspi: validate report size before copy

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

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

HID: intel-thc-hid: intel-quickspi: validate report size before copy

write_cmd_to_txdma() builds an output report in qsdev->report_buf, a heap
buffer allocated in quickspi_alloc_report_buf() to the device-descriptor
derived max_report_len (a few hundred bytes for a touch controller).  It
copies the caller-supplied report into that buffer:

    memcpy(write_buf->content, report_buf, report_buf_len);

The HID core caps a report at HID_MAX_BUFFER_SIZE (16384) by default, and
quickspi_hid_ll_driver does not set max_buffer_size, so the length reaches
the driver unbounded.  A hidraw SET_REPORT/SET_FEATURE ioctl carrying a
report larger than max_report_len therefore overflows report_buf with
attacker-controlled length and content.

Record the report_buf allocation size and reject reports that do not fit
before copying, matching the equivalent guard in the intel-quicki2c
sibling (quicki2c_init_write_buf()) and the hid-goodix-spi fix.

write_cmd_to_txdma() writes the output report header ahead of the content
in the same buffer, so size the allocation to cover the header as well.
That keeps the added bound from rejecting a maximum-sized report.

The Linux kernel CVE team has assigned CVE-2026-89620 to this issue.


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

	Issue introduced in 6.14 with commit 9d8d51735a3af40b722346931a6a1e50227df4b5 and fixed in 6.18.50 with commit 6fcefe71aeb524f6e77fe586fe85d873745e917c
	Issue introduced in 6.14 with commit 9d8d51735a3af40b722346931a6a1e50227df4b5 and fixed in 7.2.4 with commit ee8ad1bb1e96164d51089b1182f1bd5f187e7baa
	Issue introduced in 6.14 with commit 9d8d51735a3af40b722346931a6a1e50227df4b5 and fixed in 7.3-rc1 with commit a59cf84441f9a17323c89452cec2bf16724c48a9

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-2026-89620
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/intel-thc-hid/intel-quickspi/pci-quickspi.c
	drivers/hid/intel-thc-hid/intel-quickspi/quickspi-dev.h
	drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.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/6fcefe71aeb524f6e77fe586fe85d873745e917c
	https://git.kernel.org/stable/c/ee8ad1bb1e96164d51089b1182f1bd5f187e7baa
	https://git.kernel.org/stable/c/a59cf84441f9a17323c89452cec2bf16724c48a9