Unity Linux 20.1070e Security Update: kernel (UTSA-2026-131776)

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

include('compat.inc');

if (description)
{
  script_id(366588);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/16");

  script_cve_id("CVE-2022-49783");

  script_name(english:"Unity Linux 20.1070e Security Update: kernel (UTSA-2026-131776)");

  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-2026-131776 advisory.

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

    x86/fpu: Drop fpregs lock before inheriting FPU permissions

    Mike Galbraith reported the following against an old fork of preempt-rt
    but the same issue also applies to the current preempt-rt tree.

       BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
       in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: systemd
       preempt_count: 1, expected: 0
       RCU nest depth: 0, expected: 0
       Preemption disabled at:
       fpu_clone
       CPU: 6 PID: 1 Comm: systemd Tainted: G            E       (unreleased)
       Call Trace:
        <TASK>
        dump_stack_lvl
        ? fpu_clone
        __might_resched
        rt_spin_lock
        fpu_clone
        ? copy_thread
        ? copy_process
        ? shmem_alloc_inode
        ? kmem_cache_alloc
        ? kernel_clone
        ? __do_sys_clone
        ? do_syscall_64
        ? __x64_sys_rt_sigprocmask
        ? syscall_exit_to_user_mode
        ? do_syscall_64
        ? syscall_exit_to_user_mode
        ? do_syscall_64
        ? syscall_exit_to_user_mode
        ? do_syscall_64
        ? exc_page_fault
        ? entry_SYSCALL_64_after_hwframe
        </TASK>

    Mike says:

      The splat comes from fpu_inherit_perms() being called under fpregs_lock(),
      and us reaching the spin_lock_irq() therein due to fpu_state_size_dynamic()
      returning true despite static key __fpu_state_size_dynamic having never
      been enabled.

    Mike's assessment looks correct. fpregs_lock on a PREEMPT_RT kernel disables
    preemption so calling spin_lock_irq() in fpu_inherit_perms() is unsafe. This
    problem exists since commit

      9e798e9aa14c (x86/fpu: Prepare fpu_clone() for dynamically enabled features).

    Even though the original bug report should not have enabled the paths at
    all, the bug still exists.

    fpregs_lock is necessary when editing the FPU registers or a task's FP
    state but it is not necessary for fpu_inherit_perms(). The only write
    of any FP state in fpu_inherit_perms() is for the new child which is
    not running yet and cannot context switch or be borrowed by a kernel
    thread yet. Hence, fpregs_lock is not protecting anything in the new
    child until clone() completes and can be dropped earlier. The siglock
    still needs to be acquired by fpu_inherit_perms() as the read of the
    parent's permissions has to be serialised.

      [ bp: Cleanup splat. ]

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-2026-131776
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9fc4e6ca");
  # https://lore.kernel.org/linux-cve-announce/2025050120-CVE-2022-49783-a870@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?620ff46c");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2022-49783");
  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-2022-49783");

  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:"2025/05/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/16");

  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-5.10.0-79.26.uel20', 'sp':'1070e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.26.uel20', 'sp':'1070e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.26.uel20', 'sp':'1070e', 'cpu':'sw_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.26.uel20', '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_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');
}