Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100572)

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

include('compat.inc');

if (description)
{
  script_id(336713);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/17");

  script_cve_id("CVE-2026-64102");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100572)");

  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-2026-100572 advisory.

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

    RDMA/siw: Reject MPA FPDU length underflow before signed receive math

    A malicious connected siw peer can send an iWARP FPDU whose MPA length
    field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller
    than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP
    parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode]
    .hdr_len, but never compares mpa_len against that header length.

    siw_tcp_rx_data() then derives

        srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd
                             + MPA_HDR_SIZE;

    where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this
    point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest
    on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below
    hdr_len - MPA_HDR_SIZE underflows to a negative int.

    The signed value then flows into siw_proc_write()/siw_proc_rresp() as

        bytes = min(srx->fpdu_part_rem, srx->skb_new);

    is handed to siw_check_mem() as an int len (whose interval check
    addr + len > mem->va + mem->len is satisfied for a valid base when
    len is negative), and reaches siw_rx_data() -> siw_rx_kva() /
    siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header
    copy branch in skb_copy_bits() promotes that to size_t, producing a
    multi-gigabyte read.

    KASAN under a KUnit harness that drives the real kernel TCP receive
    path -- a loopback AF_INET socketpair, the malformed FPDU written via
    kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock
    dispatching to siw_tcp_rx_data -- reports:

        BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480
        Read of size 4294967295 at addr ffff888...
        Call Trace:
         skb_copy_bits
         siw_rx_kva
         siw_rx_data
         siw_check_mem
         siw_proc_write
         siw_tcp_rx_data
         __tcp_read_sock
         siw_qp_llp_data_ready
         tcp_data_ready
         tcp_data_queue

    Add the missing invariant at the earliest point where the peer header
    is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly
    the value the siw transmitter uses as the minimum mpa_len for each
    opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the
    protocol contract. Out-of-range FPDUs terminate the connection with
    TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which
    is RFC 5044 Section 8 error code 3 (Marker and ULPDU Length fields
    do not agree on the start of an FPDU), the correct framing-error
    class for this inconsistency.

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-2026-100572
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6a14ffc6");
  # https://lore.kernel.org/linux-cve-announce/2026071920-CVE-2026-64102-dcb6@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?77927a35");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-64102");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/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:N/AC:L/PR:N/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-2026-64102");

  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:"2026/06/04");
  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:"^20.1050a([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050a', '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': '1050a',
    'pkgs': [
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', '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_HOLE,
      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');
}