Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099981)

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

include('compat.inc');

if (description)
{
  script_id(336504);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/17");

  script_cve_id("CVE-2024-26629");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099981)");

  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-2026-099981 advisory.

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

    nfsd: fix RELEASE_LOCKOWNER

    The test on so_count in nfsd4_release_lockowner() is nonsense and
    harmful.  Revert to using check_for_locks(), changing that to not sleep.

    First: harmful.
    As is documented in the kdoc comment for nfsd4_release_lockowner(), the
    test on so_count can transiently return a false positive resulting in a
    return of NFS4ERR_LOCKS_HELD when in fact no locks are held.  This is
    clearly a protocol violation and with the Linux NFS client it can cause
    incorrect behaviour.

    If RELEASE_LOCKOWNER is sent while some other thread is still
    processing a LOCK request which failed because, at the time that request
    was received, the given owner held a conflicting lock, then the nfsd
    thread processing that LOCK request can hold a reference (conflock) to
    the lock owner that causes nfsd4_release_lockowner() to return an
    incorrect error.

    The Linux NFS client ignores that NFS4ERR_LOCKS_HELD error because it
    never sends NFS4_RELEASE_LOCKOWNER without first releasing any locks, so
    it knows that the error is impossible.  It assumes the lock owner was in
    fact released so it feels free to use the same lock owner identifier in
    some later locking request.

    When it does reuse a lock owner identifier for which a previous RELEASE
    failed, it will naturally use a lock_seqid of zero.  However the server,
    which didn't release the lock owner, will expect a larger lock_seqid and
    so will respond with NFS4ERR_BAD_SEQID.

    So clearly it is harmful to allow a false positive, which testing
    so_count allows.

    The test is nonsense because ... well... it doesn't mean anything.

    so_count is the sum of three different counts.
    1/ the set of states listed on so_stateids
    2/ the set of active vfs locks owned by any of those states
    3/ various transient counts such as for conflicting locks.

    When it is tested against '2' it is clear that one of these is the
    transient reference obtained by find_lockowner_str_locked().  It is not
    clear what the other one is expected to be.

    In practice, the count is often 2 because there is precisely one state
    on so_stateids.  If there were more, this would fail.

    In my testing I see two circumstances when RELEASE_LOCKOWNER is called.
    In one case, CLOSE is called before RELEASE_LOCKOWNER.  That results in
    all the lock states being removed, and so the lockowner being discarded
    (it is removed when there are no more references which usually happens
    when the lock state is discarded).  When nfsd4_release_lockowner() finds
    that the lock owner doesn't exist, it returns success.

    The other case shows an so_count of '2' and precisely one state listed
    in so_stateid.  It appears that the Linux client uses a separate lock
    owner for each file resulting in one lock state per lock owner, so this
    test on '2' is safe.  For another client it might not be safe.

    So this patch changes check_for_locks() to use the (newish)
    find_any_file_locked() so that it doesn't take a reference on the
    nfs4_file and so never calls nfsd_file_put(), and so never sleeps.  With
    this check is it safe to restore the use of check_for_locks() rather
    than testing so_count against the mysterious '2'.

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-2026-099981
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9b650e5c");
  # https://git.kernel.org/stable/c/10d75984495f7fe62152c3b0dbfa3f0a6b739c9b
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c535fbf8");
  # https://git.kernel.org/stable/c/8f5b860de87039b007e84a28a5eefc888154e098
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6d011388");
  # https://git.kernel.org/stable/c/99fb654d01dc3f08b5905c663ad6c89a9d83302f
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2b4714b3");
  # https://git.kernel.org/stable/c/b7d2eee1f53899b53f069bba3a59a419fc3d331b
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b6845baa");
  # https://git.kernel.org/stable/c/c6f8b3fcc62725e4129f2c0fd550d022d4a7685a
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dbbff633");
  # https://git.kernel.org/stable/c/e4cf8941664cae2f89f0189c29fe2ce8c6be0d03
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?86d5a8e8");
  # https://git.kernel.org/stable/c/edcf9725150e42beeca42d085149f4c88fa97afd
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7ae796ad");
  # https://lore.kernel.org/linux-cve-announce/[email protected]
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?51a7cc98");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2024-26629");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2024-26629");
  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-2024-26629");

  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:"2024/02/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/17");

  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-5.10.0-27.18.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.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');
}