Scientific Linux Security Update : libreswan on SL7.x x86_64
Medium Nessus Plugin ID 84393
SynopsisThe remote Scientific Linux host is missing one or more security updates.
DescriptionA 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.
SolutionUpdate the affected libreswan and / or libreswan-debuginfo packages.