Azure Linux 3.0 Security Update: kernel (CVE-2025-21652)

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

include('compat.inc');

if (description)
{
  script_id(295496);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/22");

  script_cve_id("CVE-2025-21652");

  script_name(english:"Azure Linux 3.0 Security Update: kernel (CVE-2025-21652)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Azure Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of kernel installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore,
affected by a vulnerability as referenced in the CVE-2025-21652 advisory.

  - In the Linux kernel, the following vulnerability has been resolved: ipvlan: Fix use-after-free in
    ipvlan_get_iflink(). syzbot presented an use-after-free report [0] regarding ipvlan and linkwatch. ipvlan
    does not hold a refcnt of the lower device unlike vlan and macvlan. If the linkwatch work is triggered for
    the ipvlan dev, the lower dev might have already been freed, resulting in UAF of ipvlan->phy_dev in
    ipvlan_get_iflink(). We can delay the lower dev unregistration like vlan and macvlan by holding the lower
    dev's refcnt in dev->netdev_ops->ndo_init() and releasing it in dev->priv_destructor(). Jakub pointed out
    calling .ndo_XXX after unregister_netdevice() has returned is error prone and suggested [1] addressing
    this UAF in the core by taking commit 750e51603395 (net: avoid potential UAF in default_operstate())
    further. Let's assume unregistering devices DOWN and use RCU protection in default_operstate() not to race
    with the device unregistration. [0]: BUG: KASAN: slab-use-after-free in ipvlan_get_iflink+0x84/0x88
    drivers/net/ipvlan/ipvlan_main.c:353 Read of size 4 at addr ffff0000d768c0e0 by task kworker/u8:35/6944
    CPU: 0 UID: 0 PID: 6944 Comm: kworker/u8:35 Not tainted 6.13.0-rc2-g9bc5c9515b48 #12
    4c3cb9e8b4565456f6a355f312ff91f4f29b3c47 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound
    linkwatch_event Call trace: show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:484 (C) __dump_stack
    lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120 print_address_description
    mm/kasan/report.c:378 [inline] print_report+0x16c/0x6f0 mm/kasan/report.c:489 kasan_report+0xc0/0x120
    mm/kasan/report.c:602 __asan_report_load4_noabort+0x20/0x30 mm/kasan/report_generic.c:380
    ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353 dev_get_iflink+0x7c/0xd8
    net/core/dev.c:674 default_operstate net/core/link_watch.c:45 [inline] rfc2863_policy+0x144/0x360
    net/core/link_watch.c:72 linkwatch_do_dev+0x60/0x228 net/core/link_watch.c:175
    __linkwatch_run_queue+0x2f4/0x5b8 net/core/link_watch.c:239 linkwatch_event+0x64/0xa8
    net/core/link_watch.c:282 process_one_work+0x700/0x1398 kernel/workqueue.c:3229 process_scheduled_works
    kernel/workqueue.c:3310 [inline] worker_thread+0x8c4/0xe10 kernel/workqueue.c:3391 kthread+0x2b0/0x360
    kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 Allocated by task 9303:
    kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x68 mm/kasan/common.c:68
    kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568 poison_kmalloc_redzone mm/kasan/common.c:377
    [inline] __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline]
    __do_kmalloc_node mm/slub.c:4283 [inline] __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4289
    __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:650 alloc_netdev_mqs+0xb4/0x1118 net/core/dev.c:11209
    rtnl_create_link+0x2b8/0xb60 net/core/rtnetlink.c:3595 rtnl_newlink_create+0x19c/0x868
    net/core/rtnetlink.c:3771 __rtnl_newlink net/core/rtnetlink.c:3896 [inline] rtnl_newlink+0x122c/0x15c0
    net/core/rtnetlink.c:4011 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901
    netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542 rtnetlink_rcv+0x34/0x50
    net/core/rtnetlink.c:6928 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
    netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x5fc/0x8b0
    net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726
    [inline] __sys_sendto+0x2ec/0x438 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline]
    __se_sys_sendto net/socket.c:2200 [inline] __arm64_sys_sendto+0xe4/0x110 net/socket.c:2200
    __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x90/0x278
    arch/arm64/kernel/syscall.c:49 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132
    do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 el ---truncated--- (CVE-2025-21652)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-21652");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  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-2025-21652");

  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:"2025/01/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/03/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/22");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:bpftool");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-accessibility");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-gpu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-intree-amdgpu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-drivers-sound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:python3-perf");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:microsoft:azure_linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Azure 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/AzureLinux/release", "Host/AzureLinux/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/AzureLinux/release');
if (isnull(release) || 'Azure Linux' >!< release) audit(AUDIT_OS_NOT, 'Azure Linux');
var os_ver = pregmatch(pattern: "Azure Linux ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Azure Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^3([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Azure Linux 3.0', 'Azure Linux ' + os_ver);

if (!get_kb_item('Host/AzureLinux/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu)
  audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Azure Linux', cpu);

var pkgs = [
    {'reference':'bpftool-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'bpftool-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-intree-amdgpu-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-intree-amdgpu-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.78.1-3.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.78.1-3.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 'Azure Linux ' + package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    if (rpm_check(release:_release, 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, 'bpftool / kernel / kernel-debuginfo / kernel-devel / kernel-docs / etc');
}