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CBL Mariner 2.0 Security Update: kernel (CVE-2024-43892)

medium Nessus Plugin ID 208923

Synopsis

The remote CBL Mariner host is missing one or more security updates.

Description

The version of kernel installed on the remote CBL Mariner 2.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2024-43892 advisory.

 - In the Linux kernel, the following vulnerability has been resolved: memcg: protect concurrent access to mem_cgroup_idr Commit 73f576c04b94 (mm: memcontrol: fix cgroup creation failure after many small jobs) decoupled the memcg IDs from the CSS ID space to fix the cgroup creation failures. It introduced IDR to maintain the memcg ID space. The IDR depends on external synchronization mechanisms for modifications. For the mem_cgroup_idr, the idr_alloc() and idr_replace() happen within css callback and thus are protected through cgroup_mutex from concurrent modifications. However idr_remove() for mem_cgroup_idr was not protected against concurrency and can be run concurrently for different memcgs when they hit their refcnt to zero. Fix that. We have been seeing list_lru based kernel crashes at a low frequency in our fleet for a long time. These crashes were in different part of list_lru code including list_lru_add(), list_lru_del() and reparenting code. Upon further inspection, it looked like for a given object (dentry and inode), the super_block's list_lru didn't have list_lru_one for the memcg of that object. The initial suspicions were either the object is not allocated through kmem_cache_alloc_lru() or somehow memcg_list_lru_alloc() failed to allocate list_lru_one() for a memcg but returned success. No evidence were found for these cases.
 Looking more deeply, we started seeing situations where valid memcg's id is not present in mem_cgroup_idr and in some cases multiple valid memcgs have same id and mem_cgroup_idr is pointing to one of them. So, the most reasonable explanation is that these situations can happen due to race between multiple idr_remove() calls or race between idr_alloc()/idr_replace() and idr_remove(). These races are causing multiple memcgs to acquire the same ID and then offlining of one of them would cleanup list_lrus on the system for all of them. Later access from other memcgs to the list_lru cause crashes due to missing list_lru_one. (CVE-2024-43892)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://nvd.nist.gov/vuln/detail/CVE-2024-43892

Plugin Details

Severity: Medium

ID: 208923

File Name: mariner_CVE-2024-43892.nasl

Version: 1.2

Type: local

Published: 10/13/2024

Updated: 11/2/2024

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Low

Base Score: 3.8

Temporal Score: 2.8

Vector: CVSS2#AV:L/AC:H/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2024-43892

CVSS v3

Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: x-cpe:/o:microsoft:cbl-mariner, p-cpe:/a:microsoft:cbl-mariner:bpftool, p-cpe:/a:microsoft:cbl-mariner:kernel, p-cpe:/a:microsoft:cbl-mariner:kernel-devel, p-cpe:/a:microsoft:cbl-mariner:kernel-docs, p-cpe:/a:microsoft:cbl-mariner:kernel-drivers-accessibility, p-cpe:/a:microsoft:cbl-mariner:kernel-drivers-sound, p-cpe:/a:microsoft:cbl-mariner:kernel-dtb, p-cpe:/a:microsoft:cbl-mariner:kernel-tools, p-cpe:/a:microsoft:cbl-mariner:python3-perf, p-cpe:/a:microsoft:cbl-mariner:kernel-drivers-gpu

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/CBLMariner/release, Host/CBLMariner/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/8/2024

Vulnerability Publication Date: 8/26/2024

Reference Information

CVE: CVE-2024-43892