Scientific Linux Security Update : libreswan on SL7.x x86_64

This script is Copyright (C) 2015 Tenable Network Security, Inc.


Synopsis :

The remote Scientific Linux host is missing one or more security
updates.

Description :

A flaw was discovered in the way Libreswan's IKE daemon processed
certain IKEv1 payloads. A remote attacker could send specially crafted
IKEv1 payloads that, when processed, would lead to a denial of service
(daemon crash). (CVE-2015-3204)

This update fixes the following bugs :

- Previously, the programs/pluto/state.h and
programs/pluto/kernel_netlink.c files had a maximum
SELinux context size of 257 and 1024 respectively. These
restrictions set by libreswan limited the size of the
context that can be exchanged by pluto (the IPSec
daemon) when using a Labeled Internet Protocol Security
(IPsec). The SElinux labels for Labeled IPsec have been
extended to 4096 bytes and the mentioned restrictions no
longer exist.

- On some architectures, the kernel AES_GCM IPsec
algorithm did not work properly with acceleration
drivers. On those kernels, some acceleration modules are
added to the modprobe blacklist. However, Libreswan was
ignoring this blacklist, leading to AES_GCM failures.
This update adds support for the module blacklist to the
libreswan packages and thus prevents the AES_GCM
failures from occurring.

- An IPv6 issue has been resolved that prevented ipv6-icmp
Neighbour Discovery from working properly once an IPsec
tunnel is established (and one endpoint reboots). When
upgrading, ensure that /etc/ipsec.conf is loading all
/etc/ipsec.d/*conf files using the /etc/ipsec.conf
'include' statement, or explicitly include this new
configuration file in /etc/ipsec.conf.

- A FIPS self-test prevented libreswan from properly
starting in FIPS mode. This bug has been fixed and
libreswan now works in FIPS mode as expected.

In addition, this update adds the following enhancements :

- A new option 'seedbits=' has been added to pre-seed the
Network Security Services (NSS) pseudo random number
generator (PRNG) function with entropy from the
/dev/random file on startup. This option is disabled by
default. It can be enabled by setting the 'seedbits='
option in the 'config setup' section in the
/etc/ipsec.conf file.

- The build process now runs a Cryptographic Algorithm
Validation Program (CAVP) certification test on the
Internet Key Exchange version 1 and 2 (IKEv1 and IKEv2)
PRF/PRF+ functions.

See also :

http://www.nessus.org/u?4cd48c00

Solution :

Update the affected libreswan and / or libreswan-debuginfo packages.

Risk factor :

Medium / CVSS Base Score : 5.0
(CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P)

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 84393 ()

Bugtraq ID:

CVE ID: CVE-2015-3204

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