RHEA-2011:1676 - Product Enhancement Advisory

Topic

Enhanced tcp_wrappers packages are now available for Red Hat Enterprise Linux 6.

Description

The tcp_wrappers packages provide small daemon programs which can monitor and
filter incoming requests for systat, finger, FTP, telnet, rlogin, rsh, exec,
tftp, talk and other network services. These packages also contain the libwrap
library, which adds the same filtering capabilities to programs linked against
it, such as to sshd among others.

This update adds the following enhancement:

• Previously, the tcp_wrappers packages were compiled without the RELRO

(read-only relocations) flag. Programs provided by this package and also
programs built against the tcp_wrappers libraries were thus vulnerable to
various attacks based on overwriting the ELF section of a program. To increase
the security of tcp_wrappers programs and libraries, the tcp_wrappers spec file
has been modified to use the "-Wl,-z,relro" flags when compiling the packages.
As a result, the tcp_wrappers packages are now provided with partial RELRO
protection. (BZ#727287)

Users of tcp_wrappers are advised to upgrade to these updated packages, which
add this enhancement.

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 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
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 727287 - Request to recompile libraries with -Wl,-z,relro flags

CVEs

(none)

References

(none)