Unity Linux 20.1070a Security Update: kernel (UTSA-2026-146347)

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

include('compat.inc');

if (description)
{
  script_id(372603);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/27");

  script_cve_id("CVE-2026-64567");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2026-146347)");

  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-2026-146347 advisory.

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

    btrfs: reject free space cache with more entries than pages

    When loading a v1 free space cache, __load_free_space_cache() takes
    num_entries and num_bitmaps straight from the on-disk
    btrfs_free_space_header. That header is stored in the tree_root under a key
    with type 0, which the tree-checker has no case for, so neither count is
    validated before the load trusts it.

    The load loops num_entries times and maps the next page whenever the current
    one runs out, going through io_ctl_check_crc() -> io_ctl_map_page(), which
    does io_ctl->pages[io_ctl->index++]. But pages[] is allocated in
    io_ctl_init() from the cache inode's i_size, not from num_entries:

            num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
            io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);

    So if num_entries claims more records than the pages can hold, io_ctl->index
    runs off the end of pages[]. The write side never hits this because
    io_ctl_add_entry() and io_ctl_add_bitmap() both stop once
    io_ctl->index >= io_ctl->num_pages; the read side just never had the same
    check.

    To trigger it, take a clean cache (num_entries = <N> here), set num_entries
    in the header to 0x10000, and fix up the leaf checksum so it still passes
    the tree-checker. The cache inode has i_size = 65536, so num_pages is 16 and
    pages[] is a 16-pointer (kmalloc-128) array. The load now tries to read
    65536 entries, io_ctl->index walks up to 16, and pages[16] is read past the
    array:

      BUG: KASAN: slab-out-of-bounds in io_ctl_check_crc (fs/btrfs/free-space-cache.c:420 fs/btrfs/free-space-
    cache.c:565)
      Read of size 8 at addr ffff88800c833a80 by task kworker/u8:3/58
       io_ctl_check_crc (fs/btrfs/free-space-cache.c:420 fs/btrfs/free-space-cache.c:565)
       __load_free_space_cache (fs/btrfs/free-space-cache.c:655 fs/btrfs/free-space-cache.c:820)
       load_free_space_cache (fs/btrfs/free-space-cache.c:1017)
       caching_thread (fs/btrfs/block-group.c:880)
       btrfs_work_helper (fs/btrfs/async-thread.c:312)
       process_one_work
       worker_thread
       kthread
       ret_from_fork

    free-space-cache.c:420 is io_ctl_map_page(), inlined into io_ctl_check_crc()
    at line 565, which is why that is the frame KASAN names. The out-of-bounds
    slot is then treated as a struct page and handed to crc32c(), so the bad
    read turns into a GP fault.

    Add the missing check to io_ctl_check_crc(), which is where both the entry
    loop and the bitmap loop end up. When num_entries is too large the load now
    fails like any corrupt cache: __load_free_space_cache() drops it and rebuilds
    the free space from the extent tree, so a valid cache is never rejected.

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-2026-146347
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4435907b");
  # https://lore.kernel.org/linux-cve-announce/2026080558-CVE-2026-64567-a7b8@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?959ccd13");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-64567");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/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:H/I:H/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-2026-64567");

  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:"2026/08/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/27");

  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:"^(20.1070a)([^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-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', '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');
}