Unity Linux 20.1070a Security Update: kernel (UTSA-2025-401373)

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

include('compat.inc');

if (description)
{
  script_id(266993);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/10/15");

  script_cve_id("CVE-2024-46828");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2025-401373)");

  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-2025-401373 advisory.

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

    sched: sch_cake: fix bulk flow accounting logic for host fairness

    In sch_cake, we keep track of the count of active bulk flows per host,
    when running in dst/src host fairness mode, which is used as the
    round-robin weight when iterating through flows. The count of active
    bulk flows is updated whenever a flow changes state.

    This has a peculiar interaction with the hash collision handling: when a
    hash collision occurs (after the set-associative hashing), the state of
    the hash bucket is simply updated to match the new packet that collided,
    and if host fairness is enabled, that also means assigning new per-host
    state to the flow. For this reason, the bulk flow counters of the
    host(s) assigned to the flow are decremented, before new state is
    assigned (and the counters, which may not belong to the same host
    anymore, are incremented again).

    Back when this code was introduced, the host fairness mode was always
    enabled, so the decrement was unconditional. When the configuration
    flags were introduced the *increment* was made conditional, but
    the *decrement* was not. Which of course can lead to a spurious
    decrement (and associated wrap-around to U16_MAX).

    AFAICT, when host fairness is disabled, the decrement and wrap-around
    happens as soon as a hash collision occurs (which is not that common in
    itself, due to the set-associative hashing). However, in most cases this
    is harmless, as the value is only used when host fairness mode is
    enabled. So in order to trigger an array overflow, sch_cake has to first
    be configured with host fairness disabled, and while running in this
    mode, a hash collision has to occur to cause the overflow. Then, the
    qdisc has to be reconfigured to enable host fairness, which leads to the
    array out-of-bounds because the wrapped-around value is retained and
    used as an array index. It seems that syzbot managed to trigger this,
    which is quite impressive in its own right.

    This patch fixes the issue by introducing the same conditional check on
    decrement as is used on increment.

    The original bug predates the upstreaming of cake, but the commit listed
    in the Fixes tag touched that code, meaning that this patch won't apply
    before that.

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-2025-401373
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b6f48e08");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2024-46828");
  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: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:H/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-2024-46828");

  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:"2024/09/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/07/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/10/07");

  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-5.10.0-74.12', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-74.12', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-74.12', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-74.12', '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');
}