CVE-2026-74352: of: reserved_mem: avoid post-init UAF when alloc_reserved_mem_array() fails

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

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

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

of: reserved_mem: avoid post-init UAF when alloc_reserved_mem_array() fails

The global pointer 'reserved_mem' continues to reference the
reserved_mem_array which lives in __initdata if
alloc_reserved_mem_array() fails. of_reserved_mem_lookup() is
exported for post-init use, that would dereference freed memory
and trigger a use-after-free.

So reset reserved_mem_count to 0 when alloc_reserved_mem_array()
fails.

The Linux kernel CVE team has assigned CVE-2026-74352 to this issue.


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

	Issue introduced in 6.13 with commit 00c9a452a235c61f099504783badd9a7675ff5a5 and fixed in 6.18.40 with commit 9af58d10d0d8c08b822de5fc99e61f31a87ede8d
	Issue introduced in 6.13 with commit 00c9a452a235c61f099504783badd9a7675ff5a5 and fixed in 7.1.5 with commit cbd3102fe27bc87da244bf4c3ba670ea4698b0a8
	Issue introduced in 6.13 with commit 00c9a452a235c61f099504783badd9a7675ff5a5 and fixed in 7.2-rc1 with commit e1686ca81dbf3edbde589b7daf312b45cbf76e03

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-2026-74352
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/of_reserved_mem.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/6d28e6ad3c5c9248577f21057baa9bf16fa9ef3b
	https://git.kernel.org/stable/c/9af58d10d0d8c08b822de5fc99e61f31a87ede8d
	https://git.kernel.org/stable/c/cbd3102fe27bc87da244bf4c3ba670ea4698b0a8
	https://git.kernel.org/stable/c/e1686ca81dbf3edbde589b7daf312b45cbf76e03