RHBA-2015:2571 - Bug Fix Advisory

Topic

Updated slapi-nis packages that fix several bugs are now available for Red Hat Enterprise Linux 7.

Description

The slapi-nis packages contain the NIS server plug-in and the Schema Compatibility plug-in for use with the 389 Directory Server.

This update fixes bugs in the Schema Compatibility plug-in (slapi-nis) to improve stability when integrated with Red Hat Enterprise Linux Identity Management:

When slapi-nis responds on an LDAP search query, it holds a read lock for the internal structure called "map cache". The map cache lock can also be taken for write when modification would be required, like responding to DELETE, ADD, or MODIFY operations. As result of the lock semantics, the write lock owner is blocked until all read lock owners release their locks. This is generally not a problem, but when readers send out LDAP query results, they call the SLAPI function that can take a long time to send out the data due to external reasons, such as network latency, clients being blocked, and others. For the duration data sending, the map cache is locked for write operations.

When Red Hat Enterprise Linux Identity Management's Kerberos Key Distribution Center (KDC) issues a Ticket-Granting Ticket (TGT), it needs to modify several Kerberos-related attributes in the principal LDAP entry. These updates are generating MOD operations visible by the slapi-nis plug-in, which triggers re-scan of map cache to potentially replace the affected entries. To perform potential replacement, slapi-nis has to take a write lock and be blocked by outstanding readers.

Therefore, it is possible to encounter a situation where an LDAP client uses Simple Authentication and Security Layer (SASL) Generic Security Services API (GSSAPI) authentication and existing Kerberos ticket did expire in during an outstanding search request. According to the LDAPv3 protocol specification, an LDAP client must perform re-negotiation before reading any outstanding PDUs. Previously, it asked Kerberos KDC for a new (or renewed) TGT, that would cause MOD updates for the primary tree which is tracked for changes by slapi-nis. These changes would be blocked by a slapi-nis reader as the client cannot finish reading outstanding PDUs yet.

Additionally, slapi-nis had several bugs which prevented the use of the ID Views feature of Red Hat Enterprise Linux Identity Management solution when providing legacy clients access to information about users and groups from trusted Active Directory (AD) forests.

(BZ#1281748, BZ#1281750, BZ#1281752)

Users of slapi-nis 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.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.2 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - TUS 7.2 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.2 x86_64
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.7 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.6 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 7.3 ppc64le
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le

Fixes

• BZ - 1281750 - duplicate ldap entries returned on getent when making usage of ID views in IPA

CVEs

(none)

References

• http://www.redhat.com/security/updates/classification/#normal