CVE-2026-64054: net: shaper: reject duplicate leaves in GROUP request

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

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

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

net: shaper: reject duplicate leaves in GROUP request

net_shaper_nl_group_doit() does not deduplicate NET_SHAPER_A_LEAVES
entries. When userspace supplies the same leaf handle twice, the same
old-parent pointer lands twice in old_nodes[]. The cleanup loop double
frees the parent. Of course the same parent may still be in old_nodes[]
twice if we are moving multiple of its leaves.

Note that this patch also implicitly fixes the fact that the
i >= leaves_count path forgets to set ret.

The Linux kernel CVE team has assigned CVE-2026-64054 to this issue.


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

	Issue introduced in 6.13 with commit 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e and fixed in 6.18.34 with commit 5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75
	Issue introduced in 6.13 with commit 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e and fixed in 7.0.11 with commit 31767bf852b59f05125b58a17007e4cd1ea9eb2e
	Issue introduced in 6.13 with commit 5d5d4700e75d861e83bf18eb6bf66ff90f85fe4e and fixed in 7.1 with commit a9a2fa1da619f276580b0d4c5d12efac89e8642b

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-2026-64054
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:
	net/shaper/shaper.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/5098b223f0f0c5c18a3884a8b0ea5bd4a0c7bd75
	https://git.kernel.org/stable/c/31767bf852b59f05125b58a17007e4cd1ea9eb2e
	https://git.kernel.org/stable/c/a9a2fa1da619f276580b0d4c5d12efac89e8642b