Unity Linux 20.1070a Security Update: kernel (UTSA-2025-988762)

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

include('compat.inc');

if (description)
{
  script_id(272759);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/05");

  script_cve_id("CVE-2021-47492");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2025-988762)");

  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-2025-988762 advisory.

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

    mm, thp: bail out early in collapse_file for writeback page

    Currently collapse_file does not explicitly check PG_writeback, instead,
    page_has_private and try_to_release_page are used to filter writeback
    pages.  This does not work for xfs with blocksize equal to or larger
    than pagesize, because in such case xfs has no page->private.

    This makes collapse_file bail out early for writeback page.  Otherwise,
    xfs end_page_writeback will panic as follows.

      page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32
      aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:libtest.so
      flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback)
      raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8
      raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000
      page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u))
      page->mem_cgroup:ffff0000c3e9a000
      ------------[ cut here ]------------
      kernel BUG at include/linux/mm.h:1212!
      Internal error: Oops - BUG: 0 [#1] SMP
      Modules linked in:
      BUG: Bad page state in process khugepaged  pfn:84ef32
       xfs(E)
      page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32
       libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ...
      CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ...
      pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
      Call trace:
        end_page_writeback+0x1c0/0x214
        iomap_finish_page_writeback+0x13c/0x204
        iomap_finish_ioend+0xe8/0x19c
        iomap_writepage_end_bio+0x38/0x50
        bio_endio+0x168/0x1ec
        blk_update_request+0x278/0x3f0
        blk_mq_end_request+0x34/0x15c
        virtblk_request_done+0x38/0x74 [virtio_blk]
        blk_done_softirq+0xc4/0x110
        __do_softirq+0x128/0x38c
        __irq_exit_rcu+0x118/0x150
        irq_exit+0x1c/0x30
        __handle_domain_irq+0x8c/0xf0
        gic_handle_irq+0x84/0x108
        el1_irq+0xcc/0x180
        arch_cpu_idle+0x18/0x40
        default_idle_call+0x4c/0x1a0
        cpuidle_idle_call+0x168/0x1e0
        do_idle+0xb4/0x104
        cpu_startup_entry+0x30/0x9c
        secondary_start_kernel+0x104/0x180
      Code: d4210000 b0006161 910c8021 94013f4d (d4210000)
      ---[ end trace 4a88c6a074082f8c ]---
      Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt

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-2025-988762
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a92d3cb4");
  # https://lore.kernel.org/linux-cve-announce/2024052241-CVE-2021-47492-ee88@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?962b790d");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2021-47492");
  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-2021-47492");

  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:"2025/11/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/11/05");

  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) 2025 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:"^20.1070a([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1070a', '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 && 'loongarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1070a',
    'pkgs': [
      {'reference':'kernel-5.10.0-79.4.2', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.4.2', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.4.2', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.4.2', 'sp':'1070a', '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');
}