RHBA-2012:0255 - Bug Fix Advisory

Topic

Updated iptables packages that fix several bugs and add two enhancements are now
available for Red Hat Enterprise Linux 5.

Description

The iptables utility controls the network packet filtering code in the Linux
kernel.

These updated iptables packages provide fixes for the following bugs:

• Prior to this update, the memory alignment of ipt_connlimit_data was incorrect

on x86-based systems. An error message in the format "ip_tables: connlimit
match: invalid size" was logged. This update adds an explicit alignment
attribute to the ipt_connlimit_data structure to correct this. (BZ#520797)

• The sysctl values for netfilter kernel modules were not restored after a

firewall restart. Consequently, the firewall did not always perform as expected
after a restart. This update applies a patch to optionally load sysctl settings
on iptables start, if specified by the user in the /etc/sysctl.conf file. Users
can now define sysctl settings to load on start and restart. (BZ#552522)

• Prior to this update, the kernel netfilter modules were not loaded at all

times. Consequently, some commands did not perform as expected the first time
they were executed. With this update, a patch has been applied to ensure the
modules are properly loaded and the problem no longer occurs. (BZ#554340)

In addition, these updated iptables packages provide the following enhancements:

• Prior to this update, the statistic match module was not included in the

iptables package. With this update, this module in now included. (BZ#471163)

• A service reload option has been added to enable a refresh of the firewall

rules without unloading netfilter kernel modules and dropping connections.
(BZ#710050)

Users are advised to upgrade to these updated iptables packages, which fix these
bugs and add these enhancements.

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/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 520797 - ip_tables: connlimit match: invalid size 24 != 16
• BZ - 552522 - Restarting iptables doesn't restore certain sysctl values, e.g. net.ipv4.ip_conntrack_max

CVEs

(none)

References

(none)