linux-cve-announce - CVE-2022-50855: bpf: prevent leak of lsm program after failed attach

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Message-ID: <2025123046-CVE-2022-50855-7845@gregkh>
Date: Tue, 30 Dec 2025 13:19:51 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50855: bpf: prevent leak of lsm program after failed attach

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

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

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

bpf: prevent leak of lsm program after failed attach

In [0], we added the ability to bpf_prog_attach LSM programs to cgroups,
but in our validation to make sure the prog is meant to be attached to
BPF_LSM_CGROUP, we return too early if the check fails. This results in
lack of decrementing prog's refcnt (through bpf_prog_put)
leaving the LSM program alive past the point of the expected lifecycle.
This fix allows for the decrement to take place.

[0] https://lore.kernel.org/all/20220628174314.1216643-4-sdf@google.com/

The Linux kernel CVE team has assigned CVE-2022-50855 to this issue.


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

	Issue introduced in 6.0 with commit 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e and fixed in 6.0.16 with commit 82b39df5ddb298daaf6dc504032ff7eb027fa106
	Issue introduced in 6.0 with commit 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e and fixed in 6.1.2 with commit 6a1504dd36cd9a0a69250d61da8bdb17b29f1fe8
	Issue introduced in 6.0 with commit 69fd337a975c7e690dfe49d9cb4fe5ba1e6db44e and fixed in 6.2 with commit e89f3edffb860a0f54a9ed16deadb7a4a1fa3862

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-2022-50855
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:
	kernel/bpf/syscall.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/82b39df5ddb298daaf6dc504032ff7eb027fa106
	https://git.kernel.org/stable/c/6a1504dd36cd9a0a69250d61da8bdb17b29f1fe8
	https://git.kernel.org/stable/c/e89f3edffb860a0f54a9ed16deadb7a4a1fa3862