RHBA-2013:0009 - Bug Fix Advisory

Topic

Updated mod_nss packages that fix multiple bugs are now available for Red Hat
Enterprise Linux 5.

Description

The mod_nss module provides strong cryptography for the Apache HTTP Server via
the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols,
using the Network Security Services (NSS) security library.

This update fixes the following bugs:

• The previous release had an incorrect post-install script. Consequently, when

upgrading "mod_nss" from version 1.0.3 to 1.0.8, the group and file permissions
were incorrectly set. The HTTP server (httpd) did not start and the following
error message was displayed:

[error] NSS_Initialize failed. Certificate database: /etc/httpd/alias.
[error] SSL Library Error: -8038 SEC_ERROR_NOT_INITIALIZED

This update improves the post-install script to set file permissions and
ownership correctly. As a result, all child processes of the Apache HTTP Server
can enable SSL and now httpd starts as expected in the scenario described.
(BZ#669963)

• With the release of "mod_nss" version 1.0.8 there was no lock mechanism to

control sequential httpd process access to the "nss_pcache" process. This
sometimes resulted in multiple requests being interpreted as a single request by
"nss_pcache" and a single result returned. The calling process sometimes
experienced a timeout error or a failure with the error message:

[error] Unable to read from pin store

With this update the code has been improved and multiple requests to the
"nss_pcache" process are processed sequentially without the errors described.
(BZ#677698)

• Due to a regression, the "mod_proxy" module no longer worked when configured

to support reverse proxy operation. The following error was logged:

[error] SSL Proxy: I don't have the name of the host we're supposed to
connect to so I can't verify that we are connecting to who we think we should
be. Giving up.

A new patch has been applied and the "mod_proxy" module now works correctly to
support SSL reverse proxy. (BZ#692868)

• Previously, a static array containing the arguments for launching the

"nss_pcache" command overflowed the array size by one. This could lead to a
variety of problems including unexpected termination. This bug has been fixed,
and "mod_nss" now uses a properly sized static array when launching
"nss_pcache". (BZ#714255)

• Due to an incorrect use of the memcpy() function in the "mod_nss" module,

running the Apache HTTP Server with this module enabled could cause some
requests to fail with the following message written to the error_log file:

request failed: error reading the headers

This update applies a patch to ensure that the memcpy() function is now used in
accordance with the current specification, and using the "mod_nss" module no
longer causes HTTP requests to fail. (BZ#749401)

• Prior to this update, client certificates were only retrieved during the

initial SSL handshake if the NSSVerifyClient option was set to "require" or
"optional". Also, the FakeBasicAuth option only retrieved Common Name rather
than the entire certificate subject. Consequently, it was possible to spoof an
identity using that option. This bug has been fixed, the FakeBasicAuth option is
now prefixed with "/" and is thus compatible with OpenSSL. Certificates are now
retrieved on all subsequent requests beyond the first one. (BZ#749402).

• When the NSS library was not initialized and "mod_nss" tried to clear its SSL

cache on start-up, "mod_nss" terminated unexpectedly when the NSS library was
built with debugging enabled. With this update, "mod_nss" does not try to clear
the SSL cache in the described scenario, thus preventing this bug. (BZ#749405,
BZ#784548)

• The "Requires: %{_libdir}/libnssckbi.so" directive has been added to the spec

file to make "libnssckbi.so" a runtime dependency. This is to prevent symbolic
links failing. (BZ#749406)

All users of mod_nss 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/knowledge/articles/11258

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 - 669963 - mod_nss's postinstall script doesn't work properly

CVEs

• CVE-2011-4973

References

(none)