Moderate: pam security, bug fix, and enhancement update

Updated pam packages that fix two security flaws, resolve several bugs, and
add enhancements are now available for Red Hat Enterprise Linux 5.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

Pluggable Authentication Modules (PAM) provide a system whereby
administrators can set up authentication policies without having to
recompile programs that handle authentication.

A flaw was found in the way pam_console set console device permissions. It
was possible for various console devices to retain ownership of the console
user after logging out, possibly leaking information to another local user.
(CVE-2007-1716)

A flaw was found in the way the PAM library wrote account names to the
audit subsystem. An attacker could inject strings containing parts of audit
messages which could possibly mislead or confuse audit log parsing tools.
(CVE-2007-3102)

As well, these updated packages fix the following bugs:

* truncated MD5-hashed passwords in "/etc/shadow" were treated as valid,
resulting in insecure and invalid passwords.

* the pam_namespace module did not convert context names to raw format and
did not unmount polyinstantiated directories in some cases. It also crashed
when an unknown user name was used in "/etc/security/namespace.conf", the
pam_namespace configuration file.

* the pam_selinux module was not relabeling the controlling tty correctly,
and in some cases it did not send complete information about user role and
level change to the audit subsystem.

These updated packages add the following enhancements:

* pam_limits module now supports parsing additional config files placed
into the /etc/security/limits.d/ directory. These files are read after the
main configuration file.

* the modules pam_limits, pam_access, and pam_time now send a message to
the audit subsystem when a user is denied access based on the number of
login sessions, origin of user, and time of login.

* pam_unix module security properties were improved. Functionality in the
setuid helper binary, unix_chkpwd, which was not required for user
authentication, was moved to a new non-setuid helper binary, unix_update.

All users of PAM should upgrade to these updated packages, which resolve
these issues and add these enhancements.

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

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

227345 - pam_namespace should convert the context names before it uses them as filenames
230120 - LSPP: Not able to log into the machine with large number of categories
232993 - FIPS 200: audit rejection based on number of sessions, origin and time
233581 - CVE-2007-1716 Ownership of devices not returned to root after logout from console
234513 - [LSPP] pam_namespace crashes with non-existent users in namespace.conf
234781 - [LSPP] incorrect information in pam_selinux audit record
236316 - LSPP: Unable to change expired password on ssh login
237163 - namespace.conf: $HOME used in polyinstantiated directory name not being expanded
237249 - LSPP: polyinstantiation behavior correct and documented
243204 - CVE-2007-3102 audit logging of failed logins

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-1716
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3102
http://www.redhat.com/security/updates/classification/#moderate

audit, device, limits, LSPP, namespace, ownership, polyinstantiation, SELinux, tty