(RHSA-2014:0321) Moderate: net-snmp security and bug fix update

The net-snmp packages provide various libraries and tools for the Simple
Network Management Protocol (SNMP), including an SNMP library, an
extensible agent, tools for requesting or setting information from SNMP
agents, tools for generating and handling SNMP traps, a version of the
netstat command which uses SNMP, and a Tk/Perl Management Information Base
(MIB) browser.

A buffer overflow flaw was found in the way the decode_icmp_msg() function
in the ICMP-MIB implementation processed Internet Control Message Protocol
(ICMP) message statistics reported in the /proc/net/snmp file. A remote
attacker could send a message for each ICMP message type, which could
potentially cause the snmpd service to crash when processing the
/proc/net/snmp file. (CVE-2014-2284)

This update also fixes the following bug:

• The snmpd service parses the /proc/diskstats file to track disk usage
  statistics for UCD-DISKIO-MIB::diskIOTable. On systems with a large number
  of block devices, /proc/diskstats may be large in size and parsing it can
  take a non-trivial amount of CPU time. With this update, Net-SNMP
  introduces a new option, ‘diskio’, in the /etc/snmp/snmpd.conf file, which
  can be used to explicitly specify devices that should be monitored.
  Only these whitelisted devices are then reported in
  UCD-DISKIO-MIB::diskIOTable, thus speeding up snmpd on systems with
  numerous block devices. (BZ#990674)

All net-snmp users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing this
update, the snmpd service will be restarted automatically.