Unity Linux 20.1070e Security Update: kernel (UTSA-2026-000503)

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

include('compat.inc');

if (description)
{
  script_id(282217);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/07");

  script_cve_id("CVE-2021-46939");

  script_name(english:"Unity Linux 20.1070e Security Update: kernel (UTSA-2026-000503)");

  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-2026-000503 advisory.

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

    tracing: Restructure trace_clock_global() to never block

    It was reported that a fix to the ring buffer recursion detection would
    cause a hung machine when performing suspend / resume testing. The
    following backtrace was extracted from debugging that case:

    Call Trace:
     trace_clock_global+0x91/0xa0
     __rb_reserve_next+0x237/0x460
     ring_buffer_lock_reserve+0x12a/0x3f0
     trace_buffer_lock_reserve+0x10/0x50
     __trace_graph_return+0x1f/0x80
     trace_graph_return+0xb7/0xf0
     ? trace_clock_global+0x91/0xa0
     ftrace_return_to_handler+0x8b/0xf0
     ? pv_hash+0xa0/0xa0
     return_to_handler+0x15/0x30
     ? ftrace_graph_caller+0xa0/0xa0
     ? trace_clock_global+0x91/0xa0
     ? __rb_reserve_next+0x237/0x460
     ? ring_buffer_lock_reserve+0x12a/0x3f0
     ? trace_event_buffer_lock_reserve+0x3c/0x120
     ? trace_event_buffer_reserve+0x6b/0xc0
     ? trace_event_raw_event_device_pm_callback_start+0x125/0x2d0
     ? dpm_run_callback+0x3b/0xc0
     ? pm_ops_is_empty+0x50/0x50
     ? platform_get_irq_byname_optional+0x90/0x90
     ? trace_device_pm_callback_start+0x82/0xd0
     ? dpm_run_callback+0x49/0xc0

    With the following RIP:

    RIP: 0010:native_queued_spin_lock_slowpath+0x69/0x200

    Since the fix to the recursion detection would allow a single recursion to
    happen while tracing, this lead to the trace_clock_global() taking a spin
    lock and then trying to take it again:

    ring_buffer_lock_reserve() {
      trace_clock_global() {
        arch_spin_lock() {
          queued_spin_lock_slowpath() {
            /* lock taken */
            (something else gets traced by function graph tracer)
              ring_buffer_lock_reserve() {
                trace_clock_global() {
                  arch_spin_lock() {
                    queued_spin_lock_slowpath() {
                    /* DEAD LOCK! */

    Tracing should *never* block, as it can lead to strange lockups like the
    above.

    Restructure the trace_clock_global() code to instead of simply taking a
    lock to update the recorded prev_time simply use it, as two events
    happening on two different CPUs that calls this at the same time, really
    doesn't matter which one goes first. Use a trylock to grab the lock for
    updating the prev_time, and if it fails, simply try again the next time.
    If it failed to be taken, that means something else is already updating
    it.


    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212761

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-2026-000503
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9c4303d6");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2021-46939");
  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-2021-46939");

  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:"2022/01/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/01/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/07");

  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:"^20.1070e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1070e', '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 ('sw_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1070e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2403.3.0.0270.105', 'sp':'1070e', 'cpu':'sw_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');
}