Synopsis: Low: dhcp security and bug fix update
Issue Date: 2013-02-21
CVE Numbers: CVE-2012-3955
A flaw was found in the way the dhcpd daemon handled the expiration time of
IPv6 leases. If dhcpd’s configuration was changed to reduce the default IPv6
lease time, lease renewal requests for previously assigned leases could cause
dhcpd to crash. (CVE-2012-3955)
This update also fixes the following bugs:
* Prior to this update, the DHCP server discovered only the first IP address of
a network interface if the network interface had more than one configured IP
address. As a consequence, the DHCP server failed to restart if the server was
configured to serve only a subnet of the following IP addresses. This update
modifies network interface addresses discovery code to find all addresses of a
network interface. The DHCP server can also serve subnets of other addresses.
* Prior to this update, the dhclient rewrote the /etc/resolv.conf file with
backup data after it was stopped even when the PEERDNS flag was set to “no”
before shut down if the configuration file was changed while the dhclient ran
with PEERDNS=yes. This update removes the backing up and restoring functions
for this configuration file from the dhclient-script. Now, the dhclient no
longer rewrites the /etc/resolv.conf file when stopped.
After installing this update, all DHCP servers will be restarted automatically.
– Scientific Linux Development Team