(RHSA-2015:2019) Low: sssd security and bug fix update

The System Security Services Daemon (SSSD) service provides a set of
daemons to manage access to remote directories and authentication
mechanisms. It also provides the Name Service Switch (NSS) and the
Pluggable Authentication Modules (PAM) interfaces toward the system, and a
pluggable back-end system to connect to multiple different account sources.

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)

This update also fixes the following bugs:

• Previously, SSSD did not correctly handle sudo rules that applied to
  groups with names containing special characters, such as the “(” opening
  parenthesis sign. Consequently, SSSD skipped such sudo rules. The internal
  sysdb search has been modified to escape special characters when searching
  for objects to which sudo rules apply. As a result, SSSD applies the
  described sudo rules as expected. (BZ#1258398)

• Prior to this update, SSSD did not correctly handle group names
  containing special Lightweight Directory Access Protocol (LDAP) characters,
  such as the “(” or “)” parenthesis signs. When a group name contained one
  or more such characters, the internal cache cleanup operation failed with
  an I/O error. With this update, LDAP special characters in the
  Distinguished Name (DN) of a cache entry are escaped before the cleanup
  operation starts. As a result, the cleanup operation completes successfully
  in the described situation. (BZ#1264098)

• Applications performing Kerberos authentication previously increased the
  memory footprint of the Kerberos plug-in that parses the Privilege
  Attribute Certificate (PAC) information. The plug-in has been updated to
  free the memory it allocates, thus fixing this bug. (BZ#1268783)

• Previously, when malformed POSIX attributes were defined in an Active
  Directory (AD) LDAP server, SSSD unexpectedly switched to offline mode.
  This update relaxes certain checks for AD POSIX attribute validity. As a
  result, SSSD now works as expected even when malformed POSIX attributes are
  present in AD and no longer enters offline mode in the described situation.
  (BZ#1268784)

All sssd users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing the
update, the sssd service will be restarted automatically. Additionally, all
running applications using the PAC responder plug-in must be restarted for
the changes to take effect.