Oracle Linux 6 / 7 : Unbreakable Enterprise kernel (ELSA-2021-9215)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2021-9215.
##

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(149296);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/09/08");

  script_cve_id(
    "CVE-2020-0465",
    "CVE-2020-0466",
    "CVE-2020-35508",
    "CVE-2021-20219",
    "CVE-2021-20261",
    "CVE-2021-28038",
    "CVE-2021-28688",
    "CVE-2021-28964",
    "CVE-2021-29650"
  );

  script_name(english:"Oracle Linux 6 / 7 : Unbreakable Enterprise kernel (ELSA-2021-9215)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 6 / 7 host has packages installed that are affected by multiple vulnerabilities as referenced in
the ELSA-2021-9215 advisory.

  - In do_epoll_ctl and ep_loop_check_proc of eventpoll.c, there is a possible use after free due to a logic
    error. This could lead to local escalation of privilege with no additional execution privileges needed.
    User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID:
    A-147802478References: Upstream kernel (CVE-2020-0466)

  - An issue was discovered in the Linux kernel through 5.11.3, as used with Xen PV. A certain part of the
    netback driver lacks necessary treatment of errors such as failed memory allocations (as a result of
    changes to the handling of grant mapping errors). A host OS denial of service may occur during misbehavior
    of a networking frontend driver. NOTE: this issue exists because of an incomplete fix for CVE-2021-26931.
    (CVE-2021-28038)

  - In various methods of hid-multitouch.c, there is a possible out of bounds write due to a missing bounds
    check. This could lead to local escalation of privilege with no additional execution privileges needed.
    User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID:
    A-162844689References: Upstream kernel (CVE-2020-0465)

  - A flaw possibility of race condition and incorrect initialization of the process id was found in the Linux
    kernel child/parent process identification handling while filtering signal handlers. A local attacker is
    able to abuse this flaw to bypass checks to send any signal to a privileged process. (CVE-2020-35508)

  - A denial of service vulnerability was found in n_tty_receive_char_special in drivers/tty/n_tty.c of the
    Linux kernel. In this flaw a local attacker with a normal user privilege could delay the loop (due to a
    changing ldata->read_head, and a missing sanity check) and cause a threat to the system availability.
    (CVE-2021-20219)

  - A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver
    software. The impact of this issue is lessened by the fact that the default permissions on the floppy
    device (/dev/fd0) are restricted to root. If the permissions on the device have changed the impact changes
    greatly. In the default configuration root (or equivalent) permissions are required to attack this flaw.
    (CVE-2021-20261)

  - The fix for XSA-365 includes initialization of pointers such that subsequent cleanup code wouldn't use
    uninitialized or stale values. This initialization went too far and may under certain conditions also
    overwrite pointers which are in need of cleaning up. The lack of cleanup would result in leaking
    persistent grants. The leak in turn would prevent fully cleaning up after a respective guest has died,
    leaving around zombie domains. All Linux versions having the fix for XSA-365 applied are vulnerable.
    XSA-365 was classified to affect versions back to at least 3.11. (CVE-2021-28688)

  - A race condition was discovered in get_old_root in fs/btrfs/ctree.c in the Linux kernel through 5.11.8. It
    allows attackers to cause a denial of service (BUG) because of a lack of locking on an extent buffer
    before a cloning operation, aka CID-dbcc7d57bffc. (CVE-2021-28964)

  - An issue was discovered in the Linux kernel before 5.11.11. The netfilter subsystem allows attackers to
    cause a denial of service (panic) because net/netfilter/x_tables.c and include/linux/netfilter/x_tables.h
    lack a full memory barrier upon the assignment of a new table value, aka CID-175e476b8cdf.
    (CVE-2021-29650)

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://linux.oracle.com/errata/ELSA-2021-9215.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/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: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-2020-0466");

  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:"2020/12/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/05/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/05/06");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:6");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:7");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-firmware");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  exit(0);
}


include('audit.inc');
include('global_settings.inc');
include('ksplice.inc');
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
var os_ver = os_ver[1];
if (! preg(pattern:"^(6|7)([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 6 / 7', 'Oracle Linux ' + os_ver);

if (!get_kb_item('Host/RedHat/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, 'Oracle Linux', cpu);
if ('x86_64' >!< cpu) audit(AUDIT_ARCH_NOT, 'x86_64', cpu);

var machine_uptrack_level = get_one_kb_item('Host/uptrack-uname-r');
if (machine_uptrack_level)
{
  var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
  var fixed_uptrack_levels = ['4.1.12-124.50.2.el6uek', '4.1.12-124.50.2.el7uek'];
  foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
    if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
    {
      audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for ELSA-2021-9215');
    }
  }
  __rpm_report = 'Running KSplice level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}

var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '4.1';
if (kernel_major_minor != expected_kernel_major_minor)
  audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);

var pkgs = [
    {'reference':'kernel-uek-4.1.12-124.50.2.el6uek', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-4.1.12'},
    {'reference':'kernel-uek-debug-4.1.12-124.50.2.el6uek', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-4.1.12'},
    {'reference':'kernel-uek-debug-devel-4.1.12-124.50.2.el6uek', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-4.1.12'},
    {'reference':'kernel-uek-devel-4.1.12-124.50.2.el6uek', 'cpu':'x86_64', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-4.1.12'},
    {'reference':'kernel-uek-doc-4.1.12-124.50.2.el6uek', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-4.1.12'},
    {'reference':'kernel-uek-firmware-4.1.12-124.50.2.el6uek', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-firmware-4.1.12'},
    {'reference':'kernel-uek-4.1.12-124.50.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-4.1.12'},
    {'reference':'kernel-uek-debug-4.1.12-124.50.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-4.1.12'},
    {'reference':'kernel-uek-debug-devel-4.1.12-124.50.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-4.1.12'},
    {'reference':'kernel-uek-devel-4.1.12-124.50.2.el7uek', 'cpu':'x86_64', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-4.1.12'},
    {'reference':'kernel-uek-doc-4.1.12-124.50.2.el7uek', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-4.1.12'},
    {'reference':'kernel-uek-firmware-4.1.12-124.50.2.el7uek', 'release':'7', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-firmware-4.1.12'}
];

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;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = 'EL' + 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 (reference && release) {
    if (exists_check) {
        if (rpm_exists(release:release, rpm:exists_check) && 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)) flag++;
    } else {
        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)) 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-uek / kernel-uek-debug / kernel-uek-debug-devel / etc');
}