RHBA-2013:1572 - Bug Fix Advisory

Topic

Updated dhcp packages that fix several bugs are now available for Red Hat
Enterprise Linux 6.

Description

The Dynamic Host Configuration Protocol (DHCP) is a protocol that allows
individual devices on an IP network to get their own network configuration
information, including an IP address, a subnet mask, and a broadcast address.
The dhcp packages provide a relay agent and ISC DHCP service required to enable
and administer DHCP on a network.

This update fixes the following bugs:

• Previously, the dhcpd daemon or the dhclient utility terminated unexpectedly

with a segmentation fault when starting on an InfiniBand network interface card
(NIC) with an alias interface and a shared-network defined. Consequently, dhcpd
and dhclient could not be used with an alias interface in a different subnet on
InfiniBand NICs. A patch has been applied to address this problem, and neither
dhcpd nor dhclient now crash in this scenario. (BZ#996518)

• Prior to this update, if some of the IPv6 addresses were not in the subnet

range declared by subnet6 in the range6 statement, the DHCPv6 server incorrectly
offered an address which was not from the client's subnet. The range6 statement
parsing code has been fixed to check whether its addresses belong to the subnet,
in which the range6 statement was declared. With this update, the DHCPv6 server
now fails to start with an error message if the range6 statement is incorrect.
(BZ#902966)

• Previously, the DHCPv4 relay agent (dhcrelay) terminated unexpectedly with a

segmentation fault if dhcrelay received a packet over an interface without any
IPv4 address assigned. With this update, dhcrelay checks whether the interface
has an address assigned prior to further processing of the received packet, and
the relay agent no longer crashes in this scenario. (BZ#863936)

• Previously, when a DHCPv6 request from a DHCPv6 client came from a random port

number, the DHCPv6 server sent the reply back to the source port of the message
instead of sending it to UDP port 546, which is standard for IPv6. Consequently,
the client got the reply on the incorrect port. The reply handling in the DHCPv6
server code has been fixed, and the server now sends replies to UDP port 546.
(BZ#952126)

• Previously, the dhcpd daemon managed memory allocations incorrectly when

manipulating objects via the Object Management API (OMAPI). As a consequence,
several memory leaks were identified in dhcpd. With this update, memory
allocation management has been fixed, and dhcpd no longer leaks memory in this
scenario. (BZ#978420)

• Prior to this update, when the dhclient utility obtained a lease containing

the "next-server" option, dhclient did not expose the option to the
dhclient-script environment. Consequently, NetworkManager was not able to use
the "next-server" option from the dhclient's lease. This bug has been fixed,
dhclient now correctly exposes the "next-server" option and NetworkManager can
use the option from the dhclient's lease. (BZ#658855)

• Previously, the dhcpd server was not able to properly handle parsing of a zone

definition which contained two or more key statements. As a consequence, dhcpd
returned a misleading error message about an internal inconsistency. The zone
statement parsing code has been fixed; the error message reported by dhcpd is
now more precise in this scenario, saying that there is a multiple key
definition for the zone. (BZ#919221)

• Previously, when the dhclient utility was running under IPv6 using multiple

interfaces, only the last started instance was configured, while others lost
connection after the lease-time had expired. Consequently, the last started
instance of dhclient received all the DHCPv6 packets, while the other instances
failed to communicate with the server. With this update, dhclient is now bound
to a specified interface, and multiple instances of dhclient communicate
correctly. (BZ#1001742)

Users of dhcp are advised to upgrade to these updated packages, which fix these
bugs.

Solution

Before applying this update, make sure all previously released errata relevant
to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the Red
Hat Network to apply this update are available at
https://access.redhat.com/site/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 658855 - Network manager doesn't expose dhcpv4 next-server option
• BZ - 863936 - dhcrelay segfaults when packet is received over interface without any IPv4 address assigned
• BZ - 952126 - Sending dhcpv6 reply to wrong port number

CVEs

(none)

References

(none)