Ubuntu: Security Advisory for linux (USN-4318-1)

# Copyright (C) 2020 Greenbone Networks GmbH
# Text descriptions are largely excerpted from the referenced
# advisory, and are Copyright (C) the respective author(s)
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.844383");
  script_version("2020-04-07T12:33:10+0000");
  script_cve_id("CVE-2020-8428", "CVE-2020-8834", "CVE-2020-8992");
  script_tag(name:"cvss_base", value:"4.9");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:L/Au:N/C:N/I:N/A:C");
  script_tag(name:"last_modification", value:"2020-04-07 12:33:10 +0000 (Tue, 07 Apr 2020)");
  script_tag(name:"creation_date", value:"2020-04-07 03:00:25 +0000 (Tue, 07 Apr 2020)");
  script_name("Ubuntu: Security Advisory for linux (USN-4318-1)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2020 Greenbone Networks GmbH");
  script_family("Ubuntu Local Security Checks");
  script_dependencies("gather-package-list.nasl");
  script_mandatory_keys("ssh/login/ubuntu_linux", "ssh/login/packages", re:"ssh/login/release=(UBUNTU18\.04 LTS|UBUNTU16\.04 LTS)");

  script_xref(name:"USN", value:"4318-1");
  script_xref(name:"URL", value:"https://lists.ubuntu.com/archives/ubuntu-security-announce/2020-April/005380.html");

  script_tag(name:"summary", value:"The remote host is missing an update for the 'linux'
  package(s) announced via the USN-4318-1 advisory.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable package version is present on the target host.");

  script_tag(name:"insight", value:"Al Viro discovered that the vfs layer in the Linux kernel contained a use-
after-free vulnerability. A local attacker could use this to cause a denial
of service (system crash) or possibly expose sensitive information (kernel
memory). (CVE-2020-8428)

Gustavo Romero and Paul Mackerras discovered that the KVM implementation in
the Linux kernel for PowerPC processors did not properly keep guest state
separate from host state. A local attacker in a KVM guest could use this to
cause a denial of service (host system crash). (CVE-2020-8834)

Shijie Luo discovered that the ext4 file system implementation in the Linux
kernel did not properly check for a too-large journal size. An attacker
could use this to construct a malicious ext4 image that, when mounted,
could cause a denial of service (soft lockup). (CVE-2020-8992)");

  script_tag(name:"affected", value:"'linux' package(s) on Ubuntu 18.04 LTS, Ubuntu 16.04 LTS.");

  script_tag(name:"solution", value:"Please install the updated package(s).");

  script_tag(name:"solution_type", value:"VendorFix");
  script_tag(name:"qod_type", value:"package");

  exit(0);
}

include("revisions-lib.inc");
include("pkg-lib-deb.inc");

release = dpkg_get_ssh_release();
if(!release)
  exit(0);

res = "";
report = "";

if(release == "UBUNTU18.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-generic", ver:"4.15.0-96.97", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-generic-lpae", ver:"4.15.0-96.97", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-lowlatency", ver:"4.15.0-96.97", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-generic", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-generic-lpae", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-lowlatency", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-powerpc-e500mc", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-powerpc-smp", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-powerpc64-emb", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-powerpc64-smp", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-virtual", ver:"4.15.0.96.87", rls:"UBUNTU18.04 LTS"))) {
    report += res;
  }

  if(report != "") {
    security_message(data:report);
  } else if(__pkg_match) {
    exit(99);
  }
  exit(0);
}

if(release == "UBUNTU16.04 LTS") {

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-generic", ver:"4.15.0-96.97~16.04.1", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-generic-lpae", ver:"4.15.0-96.97~16.04.1", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-4.15.0-96-lowlatency", ver:"4.15.0-96.97~16.04.1", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-generic-hwe-16.04", ver:"4.15.0.96.104", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-generic-lpae-hwe-16.04", ver:"4.15.0.96.104", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-lowlatency-hwe-16.04", ver:"4.15.0.96.104", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-oem", ver:"4.15.0.96.104", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"linux-image-virtual-hwe-16.04", ver:"4.15.0.96.104", rls:"UBUNTU16.04 LTS"))) {
    report += res;
  }

  if(report != "") {
    security_message(data:report);
  } else if(__pkg_match) {
    exit(99);
  }
  exit(0);
}

exit(0);