CVE-2026-72058: net: ixp4xx_hss: fix duplicate HDLC netdev allocation

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

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

net: ixp4xx_hss: fix duplicate HDLC netdev allocation

ixp4xx_hss_probe() allocates two HDLC netdevs. The first one is stored
in ndev, initialized, and registered with register_hdlc_device(). The
second one is stored in port->netdev and later used by the remove path
for unregister_hdlc_device() and free_netdev().

This means that the registered netdev is not the same object that is
unregistered and freed on remove. It also leaks the first allocation if
the second alloc_hdlcdev() call fails, and the first allocation is not
checked before ndev is used.

Older code allocated the HDLC netdev only once and stored the same object
in both the local variable and port->netdev. The buggy conversion split
this into two alloc_hdlcdev() calls. A later rename changed the local
variable name to ndev, but the underlying mismatch remained.

Fix this by allocating the HDLC netdev only once and assigning the same
object to port->netdev.

The Linux kernel CVE team has assigned CVE-2026-72058 to this issue.


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

	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 6.1.178 with commit 8f4c3c384092becbf4835a3f8ed8a3df1f544578
	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 6.6.145 with commit fd0b939ebd1eee29945a539c5ed65c35dddac8d6
	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 6.12.97 with commit ffba16e6f55948d94b7f16aa113d587c1c4c0643
	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 6.18.40 with commit 3f85fcd520aa703824b1958f35169925ddae2558
	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 7.1.5 with commit 91850f582783098415a334f8bd0a84c87ff15a8c
	Issue introduced in 5.14 with commit 99ebe65eb9c0ada015931d239d9f2d1dc8897fee and fixed in 7.2-rc1 with commit db818b0e8af7bac16860116a19c341a63d6677b4

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-2026-72058
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/wan/ixp4xx_hss.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/8f4c3c384092becbf4835a3f8ed8a3df1f544578
	https://git.kernel.org/stable/c/fd0b939ebd1eee29945a539c5ed65c35dddac8d6
	https://git.kernel.org/stable/c/ffba16e6f55948d94b7f16aa113d587c1c4c0643
	https://git.kernel.org/stable/c/3f85fcd520aa703824b1958f35169925ddae2558
	https://git.kernel.org/stable/c/91850f582783098415a334f8bd0a84c87ff15a8c
	https://git.kernel.org/stable/c/db818b0e8af7bac16860116a19c341a63d6677b4