CVE-2026-74491: of/address: Fix NULL bus dereference in of_pci_range_parser_one()

From: Greg Kroah-Hartman <[email protected]>

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

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

of/address: Fix NULL bus dereference in of_pci_range_parser_one()

The bus matching rework made of_match_bus() return NULL for nodes with
ranges/dma-ranges but no local #address-cells. parser_init() stored that
NULL bus, and the range iterator later dereferenced it.

Reject such nodes in parser_init(), leaving an explicit empty
iterator for callers that ignore the init return, and make
of_dma_get_max_cpu_address() honour the init failure so a rejected node
cannot clamp the DMA limit.

The Linux kernel CVE team has assigned CVE-2026-74491 to this issue.


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

	Issue introduced in 6.13 with commit 64ee3cf096ac590e7da2ceac1c390546bff5e240 and fixed in 6.18.44 with commit 88752b811f72aa7a16de6dad4b25031d7308673e
	Issue introduced in 6.13 with commit 64ee3cf096ac590e7da2ceac1c390546bff5e240 and fixed in 7.1.8 with commit eddd0159a8761a16a9d183676b03cf493417816e
	Issue introduced in 6.13 with commit 64ee3cf096ac590e7da2ceac1c390546bff5e240 and fixed in 7.2-rc6 with commit bba13ad17b1a11b3f1ed9b3a5d556191d7755a59

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-2026-74491
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/of/address.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/88752b811f72aa7a16de6dad4b25031d7308673e
	https://git.kernel.org/stable/c/eddd0159a8761a16a9d183676b03cf493417816e
	https://git.kernel.org/stable/c/bba13ad17b1a11b3f1ed9b3a5d556191d7755a59