Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006776)

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

include('compat.inc');

if (description)
{
  script_id(305413);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/08");

  script_cve_id("CVE-2024-35877");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006776)");

  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-2026-006776 advisory.

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

    x86/mm/pat: fix VM_PAT handling in COW mappings

    PAT handling won't do the right thing in COW mappings: the first PTE (or,
    in fact, all PTEs) can be replaced during write faults to point at anon
    folios.  Reliably recovering the correct PFN and cachemode using
    follow_phys() from PTEs will not work in COW mappings.

    Using follow_phys(), we might just get the address+protection of the anon
    folio (which is very wrong), or fail on swap/nonswap entries, failing
    follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and
    track_pfn_copy(), not properly calling free_pfn_range().

    In free_pfn_range(), we either wouldn't call memtype_free() or would call
    it with the wrong range, possibly leaking memory.

    To fix that, let's update follow_phys() to refuse returning anon folios,
    and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings
    if we run into that.

    We will now properly handle untrack_pfn() with COW mappings, where we
    don't need the cachemode.  We'll have to fail fork()->track_pfn_copy() if
    the first page was replaced by an anon folio, though: we'd have to store
    the cachemode in the VMA to make this work, likely growing the VMA size.

    For now, lets keep it simple and let track_pfn_copy() just fail in that
    case: it would have failed in the past with swap/nonswap entries already,
    and it would have done the wrong thing with anon folios.

    Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():

    <--- C reproducer --->
     #include <stdio.h>
     #include <sys/mman.h>
     #include <unistd.h>
     #include <liburing.h>

     int main(void)
     {
             struct io_uring_params p = {};
             int ring_fd;
             size_t size;
             char *map;

             ring_fd = io_uring_setup(1, &p);
             if (ring_fd < 0) {
                     perror(io_uring_setup);
                     return 1;
             }
             size = p.sq_off.array + p.sq_entries * sizeof(unsigned);

             /* Map the submission queue ring MAP_PRIVATE */
             map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
                        ring_fd, IORING_OFF_SQ_RING);
             if (map == MAP_FAILED) {
                     perror(mmap);
                     return 1;
             }

             /* We have at least one page. Let's COW it. */
             *map = 0;
             pause();
             return 0;
     }
    <--- C reproducer --->

    On a system with 16 GiB RAM and swap configured:
     # ./iouring &
     # memhog 16G
     # killall iouring
    [  301.552930] ------------[ cut here ]------------
    [  301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100
    [  301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g
    [  301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1
    [  301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4
    [  301.559569] RIP: 0010:untrack_pfn+0xf4/0x100
    [  301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000
    [  301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282
    [  301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047
    [  301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200
    [  301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000
    [  301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000
    [  301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000
    [  301.564186] FS:  0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000
    [  301.564773] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [  301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0
    [  301.565725] PKRU: 55555554
    [  301.565944] Call Trace:
    [  301.566148]  <TASK>
    [  301.566325]  ? untrack_pfn+0xf4/0x100
    [  301.566618]  ? __warn+0x81/0x130
    [  301.566876]  ? untrack_pfn+0xf4/0x100
    [  3
    ---truncated---

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-2026-006776
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2a6bd2d0");
  # https://lore.kernel.org/linux-cve-announce/2024051943-CVE-2024-35877-39e6@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4d1afbc7");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2024-35877");
  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-2024-35877");

  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:"2024/04/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/08");

  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-5.10.0-27.5', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.5', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.5', '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');
}