Unity Linux 20.1070a Security Update: kernel (UTSA-2025-988845)

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

include('compat.inc');

if (description)
{
  script_id(273031);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/05");

  script_cve_id("CVE-2021-47222");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2025-988845)");

  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-2025-988845 advisory.

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

    net: bridge: fix vlan tunnel dst refcnt when egressing

    The egress tunnel code uses dst_clone() and directly sets the result
    which is wrong because the entry might have 0 refcnt or be already deleted,
    causing number of problems. It also triggers the WARN_ON() in dst_hold()[1]
    when a refcnt couldn't be taken. Fix it by using dst_hold_safe() and
    checking if a reference was actually taken before setting the dst.

    [1] dmesg WARN_ON log and following refcnt errors
     WARNING: CPU: 5 PID: 38 at include/net/dst.h:230 br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]
     Modules linked in: 8021q garp mrp bridge stp llc bonding ipv6 virtio_net
     CPU: 5 PID: 38 Comm: ksoftirqd/5 Kdump: loaded Tainted: G        W         5.13.0-rc3+ #360
     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
     RIP: 0010:br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]
     Code: e8 85 bc 01 e1 45 84 f6 74 90 45 31 f6 85 db 48 c7 c7 a0 02 19 a0 41 0f 94 c6 31 c9 31 d2 44 89 f6
    e8 64 bc 01 e1 85 db 75 02 <0f> 0b 31 c9 31 d2 44 89 f6 48 c7 c7 70 02 19 a0 e8 4b bc 01 e1 49
     RSP: 0018:ffff8881003d39e8 EFLAGS: 00010246
     RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
     RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa01902a0
     RBP: ffff8881040c6700 R08: 0000000000000000 R09: 0000000000000001
     R10: 2ce93d0054fe0d00 R11: 54fe0d00000e0000 R12: ffff888109515000
     R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000401
     FS:  0000000000000000(0000) GS:ffff88822bf40000(0000) knlGS:0000000000000000
     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
     CR2: 00007f42ba70f030 CR3: 0000000109926000 CR4: 00000000000006e0
     Call Trace:
      br_handle_vlan+0xbc/0xca [bridge]
      __br_forward+0x23/0x164 [bridge]
      deliver_clone+0x41/0x48 [bridge]
      br_handle_frame_finish+0x36f/0x3aa [bridge]
      ? skb_dst+0x2e/0x38 [bridge]
      ? br_handle_ingress_vlan_tunnel+0x3e/0x1c8 [bridge]
      ? br_handle_frame_finish+0x3aa/0x3aa [bridge]
      br_handle_frame+0x2c3/0x377 [bridge]
      ? __skb_pull+0x33/0x51
      ? vlan_do_receive+0x4f/0x36a
      ? br_handle_frame_finish+0x3aa/0x3aa [bridge]
      __netif_receive_skb_core+0x539/0x7c6
      ? __list_del_entry_valid+0x16e/0x1c2
      __netif_receive_skb_list_core+0x6d/0xd6
      netif_receive_skb_list_internal+0x1d9/0x1fa
      gro_normal_list+0x22/0x3e
      dev_gro_receive+0x55b/0x600
      ? detach_buf_split+0x58/0x140
      napi_gro_receive+0x94/0x12e
      virtnet_poll+0x15d/0x315 [virtio_net]
      __napi_poll+0x2c/0x1c9
      net_rx_action+0xe6/0x1fb
      __do_softirq+0x115/0x2d8
      run_ksoftirqd+0x18/0x20
      smpboot_thread_fn+0x183/0x19c
      ? smpboot_unregister_percpu_thread+0x66/0x66
      kthread+0x10a/0x10f
      ? kthread_mod_delayed_work+0xb6/0xb6
      ret_from_fork+0x22/0x30
     ---[ end trace 49f61b07f775fd2b ]---
     dst_release: dst:00000000c02d677a refcnt:-1
     dst_release underflow

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-2025-988845
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1ae53ba4");
  # https://lore.kernel.org/linux-cve-announce/2024052136-CVE-2021-47222-f01c@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c8cdf753");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2021-47222");
  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-2021-47222");

  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:"2022/01/28");
  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');
}