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HistoryJul 24, 2008 - 12:00 a.m.

(RHSA-2008:0715) Low: nss_ldap security and bug fix update






The nss_ldap package contains the nss_ldap and pam_ldap modules. The
nss_ldap module is a plug-in which allows applications to retrieve
information about users and groups from a directory server. The pam_ldap
module allows PAM-aware applications to use a directory server to verify
user passwords.

A race condition was discovered in nss_ldap, which affected certain
applications that make LDAP connections, such as Dovecot. This could cause
nss_ldap to answer a request for information about one user with the
information about a different user. (CVE-2007-5794)

As well, this updated package fixes the following bugs:

  • in certain situations, on Itanium® architectures, when an application
    performed an LDAP lookup for a highly populated group, for example,
    containing more than 150 members, the application crashed, or may have
    caused a segmentation fault. As well, this issue may have caused commands,
    such as “ls”, to return a “ber_free_buf: Assertion” error.

  • when an application enumerated members of a netgroup, the nss_ldap
    module returned a successful status result and the netgroup name, even
    when the netgroup did not exist. This behavior was not consistent with
    other modules. In this updated package, nss_ldap no longer returns a
    successful status when the netgroup does not exist.

  • in master and slave server environments, with systems that were
    configured to use a read-only directory server, if user log in attempts
    were denied because their passwords had expired, and users attempted to
    immediately change their passwords, the replication server returned an LDAP
    referral, instructing the pam_ldap module to resissue its request to a
    different server; however, the pam_ldap module failed to do so. In these
    situations, an error such as the following occurred:

LDAP password information update failed: Can’t contact LDAP server
Insufficient ‘write’ privilege to the ‘userPassword’ attribute of entry

In this updated package, password changes are allowed when binding against
a slave server, which resolves this issue.

  • when a system used a directory server for naming information, and
    “nss_initgroups_ignoreusers root” was configured in “/etc/ldap.conf”,
    dbus-daemon-1 would hang. Running the “service messagebus start” command
    did not start the service, and it did not fail, which would stop the boot
    process if it was not cancelled.

As well, this updated package upgrades nss_ldap to the version as shipped
with Red Hat Enterprise Linux 5.

Users of nss_ldap are advised to upgrade to this updated package, which
resolves these issues.