(RHSA-2015:2355) Low: sssd security, bug fix, and enhancement update

The System Security Services Daemon (SSSD) service provides a set of
daemons to manage access to remote directories and authentication
mechanisms.

It was found that SSSD’s Privilege Attribute Certificate (PAC) responder
plug-in would leak a small amount of memory on each authentication request.
A remote attacker could potentially use this flaw to exhaust all available
memory on the system by making repeated requests to a Kerberized daemon
application configured to authenticate using the PAC responder plug-in.
(CVE-2015-5292)

The sssd packages have been upgraded to upstream version 1.13.0, which
provides a number of bug fixes and enhancements over the previous version.
(BZ#1205554)

Several enhancements are described in the Red Hat Enterprise Linux 7.2
Release Notes, linked to in the References section:

• SSSD smart card support (BZ#854396)
• Cache authentication in SSSD (BZ#910187)
• SSSD supports overriding automatically discovered AD site (BZ#1163806)
• SSSD can now deny SSH access to locked accounts (BZ#1175760)
• SSSD enables UID and GID mapping on individual clients (BZ#1183747)
• Background refresh of cached entries (BZ#1199533)
• Multi-step prompting for one-time and long-term passwords (BZ#1200873)
• Caching for initgroups operations (BZ#1206575)

Bugs fixed:

• When the SELinux user content on an IdM server was set to an empty
  string, the SSSD SELinux evaluation utility returned an error. (BZ#1192314)

• If the ldap_child process failed to initialize credentials and exited
  with an error multiple times, operations that create files in some cases
  started failing due to an insufficient amount of i-nodes. (BZ#1198477)

• The SRV queries used a hard coded TTL timeout, and environments that
  wanted the SRV queries to be valid for a certain time only were blocked.
  Now, SSSD parses the TTL value out of the DNS packet. (BZ#1199541)

• Previously, initgroups operation took an excessive amount of time. Now,
  logins and ID processing are faster for setups with AD back end and
  disabled ID mapping. (BZ#1201840)

• When an IdM client with Red Hat Enterprise Linux 7.1 or later was
  connecting to a server with Red Hat Enterprise Linux 7.0 or earlier,
  authentication with an AD trusted domain caused the sssd_be process to
  terminate unexpectedly. (BZ#1202170)

• If replication conflict entries appeared during HBAC processing, the user
  was denied access. Now, the replication conflict entries are skipped and
  users are permitted access. (BZ#1202245)

• The array of SIDs no longer contains an uninitialized value and SSSD no
  longer crashes. (BZ#1204203)

• SSSD supports GPOs from different domain controllers and no longer
  crashes when processing GPOs from different domain controllers.
  (BZ#1205852)

• SSSD could not refresh sudo rules that contained groups with special
  characters, such as parentheses, in their name. (BZ#1208507)

• The IPA names are not qualified on the client side if the server already
  qualified them, and IdM group members resolve even if default_domain_suffix
  is used on the server side. (BZ#1211830)

• The internal cache cleanup task has been disabled by default to improve
  performance of the sssd_be process. (BZ#1212489)

• Now, default_domain_suffix is not considered anymore for autofs maps.
  (BZ#1216285)

• The user can set subdomain_inherit=ignore_group-members to disable
  fetching group members for trusted domains. (BZ#1217350)

• The group resolution failed with an error message: “Error: 14 (Bad
  address)”. The binary GUID handling has been fixed. (BZ#1226119)

Enhancements added:

• The description of default_domain_suffix has been improved in the manual
  pages. (BZ#1185536)

• With the new “%0” template option, users on SSSD IdM clients can now use
  home directories set on AD. (BZ#1187103)

All sssd users are advised to upgrade to these updated packages, which
correct these issues and add these enhancements.