Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: kernel (UTSA-2025-991215)

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

include('compat.inc');

if (description)
{
  script_id(278500);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/12/12");

  script_cve_id("CVE-2021-46984");

  script_name(english:"Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: kernel (UTSA-2025-991215)");

  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-2025-991215 advisory.

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

    kyber: fix out of bounds access when preempted

    __blk_mq_sched_bio_merge() gets the ctx and hctx for the current CPU and
    passes the hctx to ->bio_merge(). kyber_bio_merge() then gets the ctx
    for the current CPU again and uses that to get the corresponding Kyber
    context in the passed hctx. However, the thread may be preempted between
    the two calls to blk_mq_get_ctx(), and the ctx returned the second time
    may no longer correspond to the passed hctx. This works accidentally
    most of the time, but it can cause us to read garbage if the second ctx
    came from an hctx with more ctx's than the first one (i.e., if
    ctx->index_hw[hctx->type] > hctx->nr_ctx).

    This manifested as this UBSAN array index out of bounds error reported
    by Jakub:

    UBSAN: array-index-out-of-bounds in ../kernel/locking/qspinlock.c:130:9
    index 13106 is out of range for type 'long unsigned int [128]'
    Call Trace:
     dump_stack+0xa4/0xe5
     ubsan_epilogue+0x5/0x40
     __ubsan_handle_out_of_bounds.cold.13+0x2a/0x34
     queued_spin_lock_slowpath+0x476/0x480
     do_raw_spin_lock+0x1c2/0x1d0
     kyber_bio_merge+0x112/0x180
     blk_mq_submit_bio+0x1f5/0x1100
     submit_bio_noacct+0x7b0/0x870
     submit_bio+0xc2/0x3a0
     btrfs_map_bio+0x4f0/0x9d0
     btrfs_submit_data_bio+0x24e/0x310
     submit_one_bio+0x7f/0xb0
     submit_extent_page+0xc4/0x440
     __extent_writepage_io+0x2b8/0x5e0
     __extent_writepage+0x28d/0x6e0
     extent_write_cache_pages+0x4d7/0x7a0
     extent_writepages+0xa2/0x110
     do_writepages+0x8f/0x180
     __writeback_single_inode+0x99/0x7f0
     writeback_sb_inodes+0x34e/0x790
     __writeback_inodes_wb+0x9e/0x120
     wb_writeback+0x4d2/0x660
     wb_workfn+0x64d/0xa10
     process_one_work+0x53a/0xa80
     worker_thread+0x69/0x5b0
     kthread+0x20b/0x240
     ret_from_fork+0x1f/0x30

    Only Kyber uses the hctx, so fix it by passing the request_queue to
    ->bio_merge() instead. BFQ and mq-deadline just use that, and Kyber can
    map the queues itself to avoid the mismatch.

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-2025-991215
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1d855ebe");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2021-46984");
  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-2021-46984");

  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:"2025/12/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/12/12");

  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:"^20.1050e|20.1060e|20.1070e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e / 20.1060e / 20.1070e', '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-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1050e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1060e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1060e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1060e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1060e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1070e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1070e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1070e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.80.uel20', 'sp':'1070e', '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');
}