RHBA-2019:0183 - Bug Fix Advisory

Topic

Updated krb5 packages that fix two bugs are now available for Red Hat Enterprise Linux 7.

Description

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

This update fixes the following bugs:

• Previously, the krb5 MEMORY caches were not completely thread-safe. As a consequence, multi-threaded access terminated unexpectedly in some cases. With this update, the MEMORY caches are cleaned up to be more thread-safe. As a result, no more crashes occur. (BZ#1657890)
• Previously, Red Hat Enterprise Linux 7.6 build of the krb5 system increased compliance with FIPS-140. As a consequence, certain previously permitted configurations that were prohibited by FIPS-140 stopped working. with this update, the changes have been reverted, because krb5 only needs to work in the FIPS mode, not be FIPS compliant. As a result, RHEL 7.6.z should work in the same way RHEL 7.5 did.

Please note that Red hat Enterprise Linux 8 does not support these configurations at the moment. (BZ#1659497)

Users of krb5 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 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for IBM z Systems 7 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux for Power, little endian 7 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux for ARM 64 7 aarch64
• Red Hat Enterprise Linux for Power 9 7 ppc64le
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.6 ppc64le
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for IBM System z (Structure A) 7 s390x

Fixes

• BZ - 1657890 - krb5 memory ccache cursors are invalidated by initialize, likely crashes [rhel-7.6.z]
• BZ - 1659497 - Updated krb5-libs packages in RHEL 7.6 will cause apps to crash when fips mode is on [rhel-7.6.z]

CVEs

(none)

References

(none)