Unity Linux 20.1050e Security Update: kernel (UTSA-2026-021575)

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

include('compat.inc');

if (description)
{
  script_id(315839);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/20");

  script_cve_id("CVE-2024-56758");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-021575)");

  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-2026-021575 advisory.

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

    btrfs: check folio mapping after unlock in relocate_one_folio()

    When we call btrfs_read_folio() to bring a folio uptodate, we unlock the
    folio. The result of that is that a different thread can modify the
    mapping (like remove it with invalidate) before we call folio_lock().
    This results in an invalid page and we need to try again.

    In particular, if we are relocating concurrently with aborting a
    transaction, this can result in a crash like the following:

      BUG: kernel NULL pointer dereference, address: 0000000000000000
      PGD 0 P4D 0
      Oops: 0000 [#1] SMP
      CPU: 76 PID: 1411631 Comm: kworker/u322:5
      Workqueue: events_unbound btrfs_reclaim_bgs_work
      RIP: 0010:set_page_extent_mapped+0x20/0xb0
      RSP: 0018:ffffc900516a7be8 EFLAGS: 00010246
      RAX: ffffea009e851d08 RBX: ffffea009e0b1880 RCX: 0000000000000000
      RDX: 0000000000000000 RSI: ffffc900516a7b90 RDI: ffffea009e0b1880
      RBP: 0000000003573000 R08: 0000000000000001 R09: ffff88c07fd2f3f0
      R10: 0000000000000000 R11: 0000194754b575be R12: 0000000003572000
      R13: 0000000003572fff R14: 0000000000100cca R15: 0000000005582fff
      FS:  0000000000000000(0000) GS:ffff88c07fd00000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000000000000000 CR3: 000000407d00f002 CR4: 00000000007706f0
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
      PKRU: 55555554
      Call Trace:
      <TASK>
      ? __die+0x78/0xc0
      ? page_fault_oops+0x2a8/0x3a0
      ? __switch_to+0x133/0x530
      ? wq_worker_running+0xa/0x40
      ? exc_page_fault+0x63/0x130
      ? asm_exc_page_fault+0x22/0x30
      ? set_page_extent_mapped+0x20/0xb0
      relocate_file_extent_cluster+0x1a7/0x940
      relocate_data_extent+0xaf/0x120
      relocate_block_group+0x20f/0x480
      btrfs_relocate_block_group+0x152/0x320
      btrfs_relocate_chunk+0x3d/0x120
      btrfs_reclaim_bgs_work+0x2ae/0x4e0
      process_scheduled_works+0x184/0x370
      worker_thread+0xc6/0x3e0
      ? blk_add_timer+0xb0/0xb0
      kthread+0xae/0xe0
      ? flush_tlb_kernel_range+0x90/0x90
      ret_from_fork+0x2f/0x40
      ? flush_tlb_kernel_range+0x90/0x90
      ret_from_fork_asm+0x11/0x20
      </TASK>

    This occurs because cleanup_one_transaction() calls
    destroy_delalloc_inodes() which calls invalidate_inode_pages2() which
    takes the folio_lock before setting mapping to NULL. We fail to check
    this, and subsequently call set_extent_mapping(), which assumes that
    mapping != NULL (in fact it asserts that in debug mode)

    Note that the fixes patch here is not the one that introduced the
    race (the very first iteration of this code from 2009) but a more recent
    change that made this particular crash happen in practice.

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-2026-021575
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3732d6b3");
  # https://lore.kernel.org/linux-cve-announce/2025010653-CVE-2024-56758-eeb6@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5f8520aa");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2024-56758");
  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-2024-56758");

  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:"2025/01/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/05/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/20");

  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:"^20.1050e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e', '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 && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', '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');
}