CVE-2026-89721: phy: rockchip-samsung-dcphy: fix out-of-range max_register

CVE-2026-89721: phy: rockchip-samsung-dcphy: fix out-of-range max_register

[Greg Kroah-Hartman]

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

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

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

phy: rockchip-samsung-dcphy: fix out-of-range max_register

The PHY register block is 64KB, so with a register stride of 4 the
last accessible register sits at offset 0xfffc. max_register names
0x10000, one register past the end of the mapping: dumping the
registers through the regmap debugfs interface reads beyond the
ioremapped region and oopses on the unmapped page. The oops fires
with the regmap lock held, so later PHY operations deadlock.

The Linux kernel CVE team has assigned CVE-2026-89721 to this issue.


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

	Issue introduced in 6.15 with commit b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b and fixed in 6.18.50 with commit 14afe18655c0951f4f85898f761bf92264e65ccd
	Issue introduced in 6.15 with commit b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b and fixed in 7.2.4 with commit c1a62f9dcf531d56c56da2e4435386b6d264c69f
	Issue introduced in 6.15 with commit b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b and fixed in 7.3-rc1 with commit 4486e75ba647bd8b98fc1f053101b40caceeed4b

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-2026-89721
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/phy/rockchip/phy-rockchip-samsung-dcphy.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/14afe18655c0951f4f85898f761bf92264e65ccd
	https://git.kernel.org/stable/c/c1a62f9dcf531d56c56da2e4435386b6d264c69f
	https://git.kernel.org/stable/c/4486e75ba647bd8b98fc1f053101b40caceeed4b