Unity Linux 20.1070e Security Update: kernel (UTSA-2026-013376)

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

include('compat.inc');

if (description)
{
  script_id(308133);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/21");

  script_cve_id("CVE-2023-53368");

  script_name(english:"Unity Linux 20.1070e Security Update: kernel (UTSA-2026-013376)");

  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-2026-013376 advisory.

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

    tracing: Fix race issue between cpu buffer write and swap

    Warning happened in rb_end_commit() at code:
            if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing)))

      WARNING: CPU: 0 PID: 139 at kernel/trace/ring_buffer.c:3142
            rb_commit+0x402/0x4a0
      Call Trace:
       ring_buffer_unlock_commit+0x42/0x250
       trace_buffer_unlock_commit_regs+0x3b/0x250
       trace_event_buffer_commit+0xe5/0x440
       trace_event_buffer_reserve+0x11c/0x150
       trace_event_raw_event_sched_switch+0x23c/0x2c0
       __traceiter_sched_switch+0x59/0x80
       __schedule+0x72b/0x1580
       schedule+0x92/0x120
       worker_thread+0xa0/0x6f0

    It is because the race between writing event into cpu buffer and swapping
    cpu buffer through file per_cpu/cpu0/snapshot:

      Write on CPU 0             Swap buffer by per_cpu/cpu0/snapshot on CPU 1
      --------                   --------
                                 tracing_snapshot_write()
                                   [...]

      ring_buffer_lock_reserve()
        cpu_buffer = buffer->buffers[cpu]; // 1. Suppose find 'cpu_buffer_a';
        [...]
        rb_reserve_next_event()
          [...]

                                   ring_buffer_swap_cpu()
                                     if (local_read(&cpu_buffer_a->committing))
                                         goto out_dec;
                                     if (local_read(&cpu_buffer_b->committing))
                                         goto out_dec;
                                     buffer_a->buffers[cpu] = cpu_buffer_b;
                                     buffer_b->buffers[cpu] = cpu_buffer_a;
                                     // 2. cpu_buffer has swapped here.

          rb_start_commit(cpu_buffer);
          if (unlikely(READ_ONCE(cpu_buffer->buffer)
              != buffer)) { // 3. This check passed due to 'cpu_buffer->buffer'
            [...]           //    has not changed here.
            return NULL;
          }
                                     cpu_buffer_b->buffer = buffer_a;
                                     cpu_buffer_a->buffer = buffer_b;
                                     [...]

          // 4. Reserve event from 'cpu_buffer_a'.

      ring_buffer_unlock_commit()
        [...]
        cpu_buffer = buffer->buffers[cpu]; // 5. Now find 'cpu_buffer_b' !!!
        rb_commit(cpu_buffer)
          rb_end_commit()  // 6. WARN for the wrong 'committing' state !!!

    Based on above analysis, we can easily reproduce by following testcase:
      ``` bash
      #!/bin/bash

      dmesg -n 7
      sysctl -w kernel.panic_on_warn=1
      TR=/sys/kernel/tracing
      echo 7 > ${TR}/buffer_size_kb
      echo sched:sched_switch > ${TR}/set_event
      while [ true ]; do
              echo 1 > ${TR}/per_cpu/cpu0/snapshot
      done &
      while [ true ]; do
              echo 1 > ${TR}/per_cpu/cpu0/snapshot
      done &
      while [ true ]; do
              echo 1 > ${TR}/per_cpu/cpu0/snapshot
      done &
      ```

    To fix it, IIUC, we can use smp_call_function_single() to do the swap on
    the target cpu where the buffer is located, so that above race would be
    avoided.

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-2026-013376
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?00ecf49e");
  # https://lore.kernel.org/linux-cve-announce/2025091723-CVE-2023-53368-3371@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b229945a");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2023-53368");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/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:H/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-2023-53368");

  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:"2021/07/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/21");

  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 ('aarch64' >!< cpu && 'amd64' >!< cpu && 'sw_64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1070e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2309.3.0', 'sp':'1070e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2309.3.0', 'sp':'1070e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2309.3.0', 'sp':'1070e', 'cpu':'sw_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2309.3.0', 'sp':'1070e', '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_NOTE,
      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');
}