(RHSA-2012:0313) Low: samba security, bug fix, and enhancement update

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.

The default Samba server configuration enabled both the “wide links” and
“unix extensions” options, allowing Samba clients with write access to a
share to create symbolic links that point to any location on the file
system. Clients connecting with CIFS UNIX extensions disabled could have
such links resolved on the server, allowing them to access and possibly
overwrite files outside of the share. With this update, “wide links” is
set to “no” by default. In addition, the update ensures “wide links” is
disabled for shares that have “unix extensions” enabled. (CVE-2010-0926)

Warning: This update may cause files and directories that are only linked
to Samba shares using symbolic links to become inaccessible to Samba
clients. In deployments where support for CIFS UNIX extensions is not
needed (such as when files are exported to Microsoft Windows clients),
administrators may prefer to set the “unix extensions” option to “no” to
allow the use of symbolic links to access files out of the shared
directories. All existing symbolic links in a share should be reviewed
before re-enabling “wide links”.

These updated samba packages also fix the following bug:

• The smbclient tool sometimes failed to return the proper exit status
  code. Consequently, using smbclient in a script caused some scripts to
  fail. With this update, an upstream patch has been applied and smbclient
  now returns the correct exit status. (BZ#768908)

In addition, these updated samba packages provide the following
enhancement:

• With this update, support for Windows Server 2008 R2 domains has been
  added. (BZ#736124)

Users are advised to upgrade to these updated samba packages, which correct
these issues and add this enhancement. After installing this update, the
smb service will be restarted automatically.