FreeBSD : xen-kernel -- leak of main per-domain vcpu pointer array (fc1f8795-881d-11e5-ab94-002590263bf5)

2015-11-11T00:00:00
ID FREEBSD_PKG_FC1F8795881D11E5AB94002590263BF5.NASL
Type nessus
Reporter Tenable
Modified 2015-11-11T00:00:00

Description

The Xen Project reports :

A domain's primary array of vcpu pointers can be allocated by a toolstack exactly once in the lifetime of a domain via the XEN_DOMCTL_max_vcpus hypercall. This array is leaked on domain teardown. This memory leak could -- over time -- exhaust the host's memory.

A domain given partial management control via XEN_DOMCTL_max_vcpus can mount a denial of service attack affecting the whole system. The ability to also restart or create suitable domains is also required to fully exploit the issue. Without this the leak is limited to a small multiple of the maximum number of vcpus for the domain. The maximum leak is 64kbytes per domain (re)boot (less on ARM).

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2015 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
# 
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include("compat.inc");

if (description)
{
  script_id(86842);
  script_version("$Revision: 2.1 $");
  script_cvs_date("$Date: 2015/11/11 14:43:49 $");

  script_cve_id("CVE-2015-7969");

  script_name(english:"FreeBSD : xen-kernel -- leak of main per-domain vcpu pointer array (fc1f8795-881d-11e5-ab94-002590263bf5)");
  script_summary(english:"Checks for updated package in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote FreeBSD host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The Xen Project reports :

A domain's primary array of vcpu pointers can be allocated by a
toolstack exactly once in the lifetime of a domain via the
XEN_DOMCTL_max_vcpus hypercall. This array is leaked on domain
teardown. This memory leak could -- over time -- exhaust the host's
memory.

A domain given partial management control via XEN_DOMCTL_max_vcpus can
mount a denial of service attack affecting the whole system. The
ability to also restart or create suitable domains is also required to
fully exploit the issue. Without this the leak is limited to a small
multiple of the maximum number of vcpus for the domain. The maximum
leak is 64kbytes per domain (re)boot (less on ARM)."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"http://xenbits.xen.org/xsa/advisory-149.html"
  );
  # http://www.freebsd.org/ports/portaudit/fc1f8795-881d-11e5-ab94-002590263bf5.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?7b1e1745"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:xen-kernel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/10/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/11/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/11/11");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2015 Tenable Network Security, Inc.");
  script_family(english:"FreeBSD Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


include("audit.inc");
include("freebsd_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (pkg_test(save_report:TRUE, pkg:"xen-kernel<4.5.1_1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:pkg_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");