Azure Linux 3.0 Security Update: kernel (CVE-2024-46687)

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

include('compat.inc');

if (description)
{
  script_id(296004);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/22");

  script_cve_id("CVE-2024-46687");

  script_name(english:"Azure Linux 3.0 Security Update: kernel (CVE-2024-46687)");

  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-2024-46687 advisory.

  - In the Linux kernel, the following vulnerability has been resolved: btrfs: fix a use-after-free when
    hitting errors inside btrfs_submit_chunk() [BUG] There is an internal report that KASAN is reporting use-
    after-free, with the following backtrace: BUG: KASAN: slab-use-after-free in
    btrfs_check_read_bio+0xa68/0xb70 [btrfs] Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45
    CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76 Hardware name:
    QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014
    Workqueue: btrfs-endio btrfs_end_bio_work [btrfs] Call Trace: dump_stack_lvl+0x61/0x80
    print_address_description.constprop.0+0x5e/0x2f0 print_report+0x118/0x216 kasan_report+0x11d/0x1f0
    btrfs_check_read_bio+0xa68/0xb70 [btrfs] process_one_work+0xce0/0x12a0 worker_thread+0x717/0x1250
    kthread+0x2e3/0x3c0 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x11/0x20 Allocated by task 20917:
    kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x7d/0x80
    kmem_cache_alloc_noprof+0x16e/0x3e0 mempool_alloc_noprof+0x12e/0x310 bio_alloc_bioset+0x3f0/0x7a0
    btrfs_bio_alloc+0x2e/0x50 [btrfs] submit_extent_page+0x4d1/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0
    [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560
    filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0
    do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 20917:
    kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x50
    __kasan_slab_free+0x4b/0x60 kmem_cache_free+0x214/0x5d0 bio_free+0xed/0x180 end_bbio_data_read+0x1cc/0x580
    [btrfs] btrfs_submit_chunk+0x98d/0x1880 [btrfs] btrfs_submit_bio+0x33/0x70 [btrfs]
    submit_one_bio+0xd4/0x130 [btrfs] submit_extent_page+0x3ea/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0
    [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560
    filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0
    do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [CAUSE] Although I cannot reproduce the
    error, the report itself is good enough to pin down the cause. The call trace is the regular endio
    workqueue context, but the free-by-task trace is showing that during btrfs_submit_chunk() we already hit a
    critical error, and is calling btrfs_bio_end_io() to error out. And the original endio function called
    bio_put() to free the whole bio. This means a double freeing thus causing use-after-free, e.g.: 1. Enter
    btrfs_submit_bio() with a read bio The read bio length is 128K, crossing two 64K stripes. 2. The first run
    of btrfs_submit_chunk() 2.1 Call btrfs_map_block(), which returns 64K 2.2 Call btrfs_split_bio() Now there
    are two bios, one referring to the first 64K, the other referring to the second 64K. 2.3 The first half is
    submitted. 3. The second run of btrfs_submit_chunk() 3.1 Call btrfs_map_block(), which by somehow failed
    Now we call btrfs_bio_end_io() to handle the error 3.2 btrfs_bio_end_io() calls the original endio
    function Which is end_bbio_data_read(), and it calls bio_put() for the original bio. Now the original bio
    is freed. 4. The submitted first 64K bio finished Now we call into btrfs_check_read_bio() and tries to
    advance the bio iter. But since the original bio (thus its iter) is already freed, we trigger the above
    use-after free. And even if the memory is not poisoned/corrupted, we will later call the original endio
    function, causing a double freeing. [FIX] Instead of calling btrfs_bio_end_io(), call
    btrfs_orig_bbio_end_io(), which has the extra check on split bios and do the pr ---truncated---
    (CVE-2024-46687)

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-2024-46687");
  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-2024-46687");

  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:"2024/09/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/10/08");
  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-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-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'bpftool-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-debuginfo-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-devel-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-docs-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-accessibility-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-gpu-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-drivers-sound-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'kernel-tools-6.6.51.1-5.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.51.1-5.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-perf-6.6.51.1-5.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');
}