Unity Linux 20.1070a Security Update: kernel (UTSA-2025-989601)

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

include('compat.inc');

if (description)
{
  script_id(272979);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/05");

  script_cve_id("CVE-2022-49520");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2025-989601)");

  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-2025-989601 advisory.

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

    arm64: compat: Do not treat syscall number as ESR_ELx for a bad syscall

    If a compat process tries to execute an unknown system call above the
    __ARM_NR_COMPAT_END number, the kernel sends a SIGILL signal to the
    offending process. Information about the error is printed to dmesg in
    compat_arm_syscall() -> arm64_notify_die() -> arm64_force_sig_fault() ->
    arm64_show_signal().

    arm64_show_signal() interprets a non-zero value for
    current->thread.fault_code as an exception syndrome and displays the
    message associated with the ESR_ELx.EC field (bits 31:26).
    current->thread.fault_code is set in compat_arm_syscall() ->
    arm64_notify_die() with the bad syscall number instead of a valid ESR_ELx
    value. This means that the ESR_ELx.EC field has the value that the user set
    for the syscall number and the kernel can end up printing bogus exception
    messages*. For example, for the syscall number 0x68000000, which evaluates
    to ESR_ELx.EC value of 0x1A (ESR_ELx_EC_FPAC) the kernel prints this error:

    [   18.349161] syscall[300]: unhandled exception: ERET/ERETAA/ERETAB, ESR 0x68000000, Oops - bad compat
    syscall(2) in syscall[10000+50000]
    [   18.350639] CPU: 2 PID: 300 Comm: syscall Not tainted 5.18.0-rc1 #79
    [   18.351249] Hardware name: Pine64 RockPro64 v2.0 (DT)
    [..]

    which is misleading, as the bad compat syscall has nothing to do with
    pointer authentication.

    Stop arm64_show_signal() from printing exception syndrome information by
    having compat_arm_syscall() set the ESR_ELx value to 0, as it has no
    meaning for an invalid system call number. The example above now becomes:

    [   19.935275] syscall[301]: unhandled exception: Oops - bad compat syscall(2) in syscall[10000+50000]
    [   19.936124] CPU: 1 PID: 301 Comm: syscall Not tainted 5.18.0-rc1-00005-g7e08006d4102 #80
    [   19.936894] Hardware name: Pine64 RockPro64 v2.0 (DT)
    [..]

    which although shows less information because the syscall number,
    wrongfully advertised as the ESR value, is missing, it is better than
    showing plainly wrong information. The syscall number can be easily
    obtained with strace.

    *A 32-bit value above or equal to 0x8000_0000 is interpreted as a negative
    integer in compat_arm_syscal() and the condition scno < __ARM_NR_COMPAT_END
    evaluates to true; the syscall will exit to userspace in this case with the
    ENOSYS error code instead of arm64_notify_die() being called.

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-2025-989601
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2000c41e");
  # https://lore.kernel.org/linux-cve-announce/2025022611-CVE-2022-49520-465c@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?92878f3c");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2022-49520");
  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-2022-49520");

  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:"2022/07/15");
  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');
}