CVE-2026-68108: drm/amdgpu/vce: fix integer overflow in image size

CVE-2026-68108: drm/amdgpu/vce: fix integer overflow in image size

[Greg Kroah-Hartman]

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

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

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

drm/amdgpu/vce: fix integer overflow in image size

Fix a security vulnerability where malicious VCE command streams
with oversized dimensions (e.g. 65536×65536) cause 32-bit integer
overflow, wrapping the calculated buffer size to 0. This bypasses
validation and allows GPU firmware to perform out-of-bound memory
access.

The fix uses 64-bit arithmetic to detect overflow and rejects
invalid dimensions before they reach the hardware.

V2: remove redundant check
V3: modify max height value
V4: remove size64

(cherry picked from commit cbe408dba581755ad1279a487ec786d8927d778d)

The Linux kernel CVE team has assigned CVE-2026-68108 to this issue.


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

	Fixed in 6.6.148 with commit a07430abd556de3707adfcadcc60db3fa64e4b2b
	Fixed in 6.12.101 with commit a6d7065b91a14790980ce6f4960db0ca8c3c9940
	Fixed in 6.18.42 with commit 7eebef042c12dfe0568593ee6a8926d16505925e
	Fixed in 7.1.6 with commit 00c311a13d225266800c712f2b7db2711c6897de
	Fixed in 7.2-rc2 with commit 186bfdc4e26d019b2e7570cb121964a1d89b2e5b

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-2026-68108
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/gpu/drm/amd/amdgpu/amdgpu_vce.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/a07430abd556de3707adfcadcc60db3fa64e4b2b
	https://git.kernel.org/stable/c/a6d7065b91a14790980ce6f4960db0ca8c3c9940
	https://git.kernel.org/stable/c/7eebef042c12dfe0568593ee6a8926d16505925e
	https://git.kernel.org/stable/c/00c311a13d225266800c712f2b7db2711c6897de
	https://git.kernel.org/stable/c/186bfdc4e26d019b2e7570cb121964a1d89b2e5b