Moderate: samba4 security, bug fix and enhancement update

Synopsis

Moderate: samba4 security, bug fix and enhancement update

Type/Severity

Security Advisory: Moderate

Topic

Updated samba4 packages that fix one security issue, multiple bugs, and add
various enhancements are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

Description

Samba is an open-source implementation of the Server Message Block (SMB) or
Common Internet File System (CIFS) protocol, which allows PC-compatible
machines to share files, printers, and other information.

A flaw was found in the Samba suite's Perl-based DCE/RPC IDL (PIDL)
compiler, used to generate code to handle RPC calls. This could result in
code generated by the PIDL compiler to not sufficiently protect against
buffer overflows. (CVE-2012-1182)

The samba4 packages have been upgraded to upstream version 4.0.0, which
provides a number of bug fixes and enhancements over the previous version.
In particular, improved interoperability with Active Directory (AD)
domains. SSSD now uses the libndr-krb5pac library to parse the Privilege
Attribute Certificate (PAC) issued by an AD Key Distribution Center (KDC).

The Cross Realm Kerberos Trust functionality provided by Identity
Management, which relies on the capabilities of the samba4 client library,
is included as a Technology Preview. This functionality and server
libraries, is included as a Technology Preview. This functionality uses the
libndr-nbt library to prepare Connection-less Lightweight Directory Access
Protocol (CLDAP) messages.

Additionally, various improvements have been made to the Local Security
Authority (LSA) and Net Logon services to allow verification of trust
from a Windows system. Because the Cross Realm Kerberos Trust functionality
is considered a Technology Preview, selected samba4 components are
considered to be a Technology Preview. For more information on which Samba
packages are considered a Technology Preview, refer to Table 5.1, "Samba4
Package Support" in the Release Notes, linked to from the References.
(BZ#766333, BZ#882188)

This update also fixes the following bug:

• Prior to this update, if the Active Directory (AD) server was rebooted,
  Winbind sometimes failed to reconnect when requested by "wbinfo -n" or
  "wbinfo -s" commands. Consequently, looking up users using the wbinfo tool
  failed. This update applies upstream patches to fix this problem and now
  looking up a Security Identifier (SID) for a username, or a username for a
  given SID, works as expected after a domain controller is rebooted.
  (BZ#878564)
  

All users of samba4 are advised to upgrade to these updated packages,
which fix these issues and add these enhancements.

Warning: If you upgrade from Red Hat Enterprise Linux 6.3 to Red Hat
Enterprise Linux 6.4 and you have Samba in use, you should make sure that
you uninstall the package named "samba4" to avoid conflicts during the
upgrade.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386

Fixes

• BZ - 766333 - Rebase Samba4 libraries to pick up functionality required for IdM
• BZ - 804093 - CVE-2012-1182 samba: Multiple heap-based buffer overflows in memory management based on NDR marshalling code output
• BZ - 861892 - samba4's wbclient/smbclient provides need to be filtered to avoid confusion with samba's wbclient/smbclient provides
• BZ - 864889 - Configure winbind_krb5_locator.so via alternatives to allow IPA AD trusts use
• BZ - 867317 - pam_winbind.conf is not packaged in samba-winbind-clients where the module is packaged.
• BZ - 867854 - auth_builtin auth_domain auth_sam and auth_winbind are built as shared modules.
• BZ - 868248 - samba-winbind package wants /var/log/samba
• BZ - 868419 - samba4 smb and winbind init scripts missing export KRB5CCNAME
• BZ - 877085 - Wrong sysconfig filename
• BZ - 878564 - IPA trust cannot always lookup AD users with wbinfo
• BZ - 882188 - samba4-libs: yyin symbol collision
• BZ - 885089 - Samba netlogon AES support incorrect
• BZ - 886157 - samba4 should use the same winbind pipes as samba
• BZ - 895718 - Incomplete rpm provides filters causes issues with the samba4-libs package on certain architectures

CVEs

• CVE-2012-1182

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.4_Release_Notes/index.html