CVE-2026-68366: usb: gadget: uvc: clamp SEND_RESPONSE length to the response buffer

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

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

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

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

usb: gadget: uvc: clamp SEND_RESPONSE length to the response buffer

uvc_send_response() builds the UVC control response from a user-supplied
struct uvc_request_data:

	req->length = min_t(unsigned int, uvc->event_length, data->length);
	...
	memcpy(req->buf, data->data, req->length);

req->length is clamped to uvc->event_length, which is taken from the
host control request wLength (up to UVC_MAX_REQUEST_SIZE, 64), and to
data->length, which comes from the UVCIOC_SEND_RESPONSE ioctl and is
only checked for being negative.  The source buffer data->data is only
60 bytes, so a response with uvc->event_length and data->length both
greater than 60 makes memcpy() read past the end of data->data.

Clamp req->length to sizeof(data->data) as well.

The Linux kernel CVE team has assigned CVE-2026-68366 to this issue.


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

	Issue introduced in 3.10 with commit a5eaaa1f33e771fa1651a4a7652b8a5f9fa7f6c1 and fixed in 6.6.148 with commit 4e116372b7a4f87df0dc0ed4b0ab5b0bb0cc5796
	Issue introduced in 3.10 with commit a5eaaa1f33e771fa1651a4a7652b8a5f9fa7f6c1 and fixed in 6.12.101 with commit 662f6c6c6ff8a6c508e1646c09cae74e28f3cca6
	Issue introduced in 3.10 with commit a5eaaa1f33e771fa1651a4a7652b8a5f9fa7f6c1 and fixed in 6.18.42 with commit 1f03658f3e9b2f8fd1d1003ba389a0390b49a350
	Issue introduced in 3.10 with commit a5eaaa1f33e771fa1651a4a7652b8a5f9fa7f6c1 and fixed in 7.1.6 with commit c8510fbbea09ef0170b56b14dc2b5890dc75be07
	Issue introduced in 3.10 with commit a5eaaa1f33e771fa1651a4a7652b8a5f9fa7f6c1 and fixed in 7.2-rc5 with commit b70dc75e85ba968b7b76eebfe5d63000080b875b

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-2026-68366
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/usb/gadget/function/uvc_v4l2.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/4e116372b7a4f87df0dc0ed4b0ab5b0bb0cc5796
	https://git.kernel.org/stable/c/662f6c6c6ff8a6c508e1646c09cae74e28f3cca6
	https://git.kernel.org/stable/c/1f03658f3e9b2f8fd1d1003ba389a0390b49a350
	https://git.kernel.org/stable/c/c8510fbbea09ef0170b56b14dc2b5890dc75be07
	https://git.kernel.org/stable/c/b70dc75e85ba968b7b76eebfe5d63000080b875b