Unity Linux 20.1050e Security Update: kernel (UTSA-2026-005154)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(296892);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/27");

  script_cve_id("CVE-2024-49867");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-005154)");

  script_set_attribute(attribute:"synopsis", value:
"The Unity Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the
UTSA-2026-005154 advisory.

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

    btrfs: wait for fixup workers before stopping cleaner kthread during umount

    During unmount, at close_ctree(), we have the following steps in this order:

    1) Park the cleaner kthread - this doesn't destroy the kthread, it basically
       halts its execution (wake ups against it work but do nothing);

    2) We stop the cleaner kthread - this results in freeing the respective
       struct task_struct;

    3) We call btrfs_stop_all_workers() which waits for any jobs running in all
       the work queues and then free the work queues.

    Syzbot reported a case where a fixup worker resulted in a crash when doing
    a delayed iput on its inode while attempting to wake up the cleaner at
    btrfs_add_delayed_iput(), because the task_struct of the cleaner kthread
    was already freed. This can happen during unmount because we don't wait
    for any fixup workers still running before we call kthread_stop() against
    the cleaner kthread, which stops and free all its resources.

    Fix this by waiting for any fixup workers at close_ctree() before we call
    kthread_stop() against the cleaner and run pending delayed iputs.

    The stack traces reported by syzbot were the following:

      BUG: KASAN: slab-use-after-free in __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065
      Read of size 8 at addr ffff8880272a8a18 by task kworker/u8:3/52

      CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.12.0-rc1-syzkaller #0
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
      Workqueue: btrfs-fixup btrfs_work_helper
      Call Trace:
       <TASK>
       __dump_stack lib/dump_stack.c:94 [inline]
       dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
       print_address_description mm/kasan/report.c:377 [inline]
       print_report+0x169/0x550 mm/kasan/report.c:488
       kasan_report+0x143/0x180 mm/kasan/report.c:601
       __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
       try_to_wake_up+0xb0/0x1480 kernel/sched/core.c:4154
       btrfs_writepage_fixup_worker+0xc16/0xdf0 fs/btrfs/inode.c:2842
       btrfs_work_helper+0x390/0xc50 fs/btrfs/async-thread.c:314
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f0/0x390 kernel/kthread.c:389
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
       </TASK>

      Allocated by task 2:
       kasan_save_stack mm/kasan/common.c:47 [inline]
       kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
       unpoison_slab_object mm/kasan/common.c:319 [inline]
       __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
       kasan_slab_alloc include/linux/kasan.h:247 [inline]
       slab_post_alloc_hook mm/slub.c:4086 [inline]
       slab_alloc_node mm/slub.c:4135 [inline]
       kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4187
       alloc_task_struct_node kernel/fork.c:180 [inline]
       dup_task_struct+0x57/0x8c0 kernel/fork.c:1107
       copy_process+0x5d1/0x3d50 kernel/fork.c:2206
       kernel_clone+0x223/0x880 kernel/fork.c:2787
       kernel_thread+0x1bc/0x240 kernel/fork.c:2849
       create_kthread kernel/kthread.c:412 [inline]
       kthreadd+0x60d/0x810 kernel/kthread.c:765
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

      Freed by task 61:
       kasan_save_stack mm/kasan/common.c:47 [inline]
       kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
       kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
       poison_slab_object mm/kasan/common.c:247 [inline]
       __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
       kasan_slab_free include/linux/kasan.h:230 [inline]
       slab_free_h
    ---truncated---

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://src.uniontech.com/#/security_advisory_detail?utsa_id=UTSA-2026-005154
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?eacf3944");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2024-49867");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2024-49867");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2024/10/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/01/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/27");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Unity Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/UOS-Server/release", "Host/UOS-Server/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'UOS Server' >!< os_product) audit(AUDIT_OS_NOT, 'UOS Server');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'UOS Server');
if (! preg(pattern:"^20.1050e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e', 'UOS Server ' + os_version);

if (!get_kb_item('Host/UOS-Server/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'amd64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2211.5.0.0178.47', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.47', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.47', 'sp':'1050e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}


if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'kernel');
}