CVE-2026-72047: ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit

CVE-2026-72047: ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit

[Greg Kroah-Hartman]

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

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

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

ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit

ca8210_test_int_driver_write() and ca8210_test_int_user_read() exchange
a kmalloc'd buffer pointer through a struct kfifo, but pass a literal
'4' as the byte count to kfifo_in()/kfifo_out().

This is correct on 32-bit (pointer = 4 bytes), but on 64-bit only the
low 4 bytes of the 8-byte pointer are written into the FIFO. The reader
then reads back 4 bytes into an 8-byte local pointer variable, leaving
the upper 4 bytes uninitialized stack data. The first dereference of
the reconstructed pointer (fifo_buffer[1]) accesses an arbitrary kernel
address and generally results in an oops.

Use sizeof(fifo_buffer) so the byte count matches pointer width on every
architecture.

The driver has no architecture restriction in Kconfig, so any 64-bit
build with CONFIG_IEEE802154_CA8210_DEBUGFS=y is exposed. Issue has
been latent since the driver was added in 2017 because it is most
commonly deployed on 32-bit MCUs.

Found via a custom Coccinelle semantic patch hunting for short-byte
kfifo I/O on byte-mode kfifos used to shuttle pointers.

The Linux kernel CVE team has assigned CVE-2026-72047 to this issue.


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

	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 5.10.261 with commit 2c1664ccfae653979b38788211240b5a1ee317ed
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 5.15.212 with commit 093aacb0c56d5c693e3169a0224062e77c3fd0c0
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 6.1.178 with commit 87dab14a4f68895d6f4d798e6ee3556cd64e8c72
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 6.6.145 with commit 1fe2643d0b24ca3cdd61a31a45c2d3233dc6cbfe
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 6.12.97 with commit 65dc342274a01616f5c17105f7360a3b4bfd7a3d
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 6.18.40 with commit 2059c28bd725beded01277cdf1f67be33e714323
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 7.1.5 with commit d8ce67fa6a5e6929f5414e933ff9665176c2bce6
	Issue introduced in 4.12 with commit ded845a781a578dfb0b5b2c138e5a067aa3b1242 and fixed in 7.2-rc1 with commit 6d7f7bcf225b2d566176bf6229dbd1252940cb3c

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-2026-72047
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/net/ieee802154/ca8210.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/2c1664ccfae653979b38788211240b5a1ee317ed
	https://git.kernel.org/stable/c/093aacb0c56d5c693e3169a0224062e77c3fd0c0
	https://git.kernel.org/stable/c/87dab14a4f68895d6f4d798e6ee3556cd64e8c72
	https://git.kernel.org/stable/c/1fe2643d0b24ca3cdd61a31a45c2d3233dc6cbfe
	https://git.kernel.org/stable/c/65dc342274a01616f5c17105f7360a3b4bfd7a3d
	https://git.kernel.org/stable/c/2059c28bd725beded01277cdf1f67be33e714323
	https://git.kernel.org/stable/c/d8ce67fa6a5e6929f5414e933ff9665176c2bce6
	https://git.kernel.org/stable/c/6d7f7bcf225b2d566176bf6229dbd1252940cb3c