CVE-2026-64361: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length

CVE-2026-64361: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length

[Greg Kroah-Hartman]

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

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

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

hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length

check_and_correct_requested_length() compares (off + len) against
node_size using u32 arithmetic.  When the caller passes a large len
value (e.g. from an underflowed subtraction in hfs_brec_remove()),
off + len can wrap past 2^32 and produce a small result, causing the
bounds check to pass when it should fail.

For example, with off=14 and len=0xFFFFFFF2 (underflowed from
data_off - keyoffset - size in hfs_brec_remove), off + len wraps to 6,
which is less than a typical node_size of 512, so the check passes and
the subsequent memmove reads ~4GB past the node buffer.

Fix this by widening the addition to u64 before comparing against
node_size.  This prevents the u32 wrap while keeping the logic
straightforward.

The Linux kernel CVE team has assigned CVE-2026-64361 to this issue.


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

	Issue introduced in 5.10.241 with commit 67ecc81f6492275c9c54280532f558483c99c90e and fixed in 5.10.261 with commit c8dd112173c02adf539fe2ad34a45f5e0068780d
	Issue introduced in 5.15.190 with commit a1a60e79502279f996e55052f50cc14919020475 and fixed in 5.15.212 with commit fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1
	Issue introduced in 6.1.149 with commit fe2891a9c43ab87d1a210d61e6438ca6936e2f62 and fixed in 6.1.178 with commit 671c3fcc2ad31c1311ea6414382a2d95104ae1b9
	Issue introduced in 6.6.103 with commit 384a66b89f9540a9a8cb0f48807697dfabaece4c and fixed in 6.6.145 with commit b6a481642ea1977be2f84dc08c5affd742c177e7
	Issue introduced in 6.12.43 with commit efc095b35b23297e419c2ab4fc1ed1a8f0781a29 and fixed in 6.12.97 with commit 7399c3baee7bb622a92f0b895cd4d3009a693f2b
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 6.18.40 with commit 607217f7ad419b53926f71e3f75001813bbc08ad
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 7.1.4 with commit c25d3c931a63e762fcaa9cb125b901c53b62403f
	Issue introduced in 6.17 with commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 and fixed in 7.2-rc1 with commit 966cb76fb2857a4242cab6ea2ea17acf818a3da7
	Issue introduced in 5.4.297 with commit e7d2dc2421e821e4045775e6dc226378328de6f6
	Issue introduced in 6.15.11 with commit fc7f732984ec91f30be3e574e0644066d07f2b78
	Issue introduced in 6.16.2 with commit eec522fd0d28106b14a59ab2d658605febe4a3bb

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-2026-64361
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:
	fs/hfs/bnode.c
	fs/hfsplus/hfsplus_fs.h


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/c8dd112173c02adf539fe2ad34a45f5e0068780d
	https://git.kernel.org/stable/c/fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1
	https://git.kernel.org/stable/c/671c3fcc2ad31c1311ea6414382a2d95104ae1b9
	https://git.kernel.org/stable/c/b6a481642ea1977be2f84dc08c5affd742c177e7
	https://git.kernel.org/stable/c/7399c3baee7bb622a92f0b895cd4d3009a693f2b
	https://git.kernel.org/stable/c/607217f7ad419b53926f71e3f75001813bbc08ad
	https://git.kernel.org/stable/c/c25d3c931a63e762fcaa9cb125b901c53b62403f
	https://git.kernel.org/stable/c/966cb76fb2857a4242cab6ea2ea17acf818a3da7