Synopsis

Low: cifs-utils security, bug fix, and enhancement update

Type/Severity

Security Advisory: Low

Topic

An updated cifs-utils package that fixes one security issue, multiple bugs,
and adds various enhancements is now available for Red Hat
Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having low
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

The cifs-utils package contains tools for mounting and managing shares on
Linux using the SMB/CIFS protocol. The CIFS shares can be used as standard
Linux file systems.

A file existence disclosure flaw was found in mount.cifs. If the tool was
installed with the setuid bit set, a local attacker could use this flaw to
determine the existence of files or directories in directories not
accessible to the attacker. (CVE-2012-1586)

Note: mount.cifs from the cifs-utils package distributed by Red Hat does
not have the setuid bit set. We recommend that administrators do not
manually set the setuid bit for mount.cifs.

This update also fixes the following bugs:

• The cifs.mount(8) manual page was previously missing documentation for
  several mount options. With this update, the missing entries have been
  added to the manual page. (BZ#769923)
  
• Previously, the mount.cifs utility did not properly update the
  "/etc/mtab" system information file when remounting an existing CIFS
  mount. Consequently, mount.cifs created a duplicate entry of the existing
  mount entry. This update adds the del_mtab() function to cifs.mount, which
  ensures that the old mount entry is removed from "/etc/mtab" before adding
  the updated mount entry. (BZ#770004)
  
• The mount.cifs utility did not properly convert user and group names to
  numeric UIDs and GIDs. Therefore, when the "uid", "gid" or "cruid" mount
  options were specified with user or group names, CIFS shares were mounted
  with default values. This caused shares to be inaccessible to the intended
  users because UID and GID is set to "0" by default. With this update, user
  and group names are properly converted so that CIFS shares are now mounted
  with specified user and group ownership as expected. (BZ#796463)
  
• The cifs.upcall utility did not respect the "domain_realm" section in
  the "krb5.conf" file and worked only with the default domain.
  Consequently, an attempt to mount a CIFS share from a different than the
  default domain failed with the following error message:
  

mount error(126): Required key not available

This update modifies the underlying code so that cifs.upcall handles
multiple Kerberos domains correctly and CIFS shares can now be mounted as
expected in a multi-domain environment. (BZ#805490)

In addition, this update adds the following enhancements:

• The cifs.upcall utility previously always used the "/etc/krb5.conf" file
  regardless of whether the user had specified a custom Kerberos
  configuration file. This update adds the "--krb5conf" option to
  cifs.upcall allowing the administrator to specify an alternate
  krb5.conf file. For more information on this option, refer to the
  cifs.upcall(8) manual page. (BZ#748756)
  
• The cifs.upcall utility did not optimally determine the correct service
  principal name (SPN) used for Kerberos authentication, which occasionally
  caused krb5 authentication to fail when mounting a server's unqualified
  domain name. This update improves cifs.upcall so that the method used to
  determine the SPN is now more versatile. (BZ#748757)
  
• This update adds the "backupuid" and "backupgid" mount options to the
  mount.cifs utility. When specified, these options grant a user or a group
  the right to access files with the backup intent. For more information on
  these options, refer to the mount.cifs(8) manual page. (BZ#806337)
  

All users of cifs-utils are advised to upgrade to this updated package,
which contains backported patches to fix these issues and add these
enhancements.

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 - 748756 - mount.cifs does not use KRB5_CONFIG
• BZ - 748757 - RFE: Improve selection of SPNs with cifs.upcall
• BZ - 807252 - CVE-2012-1586 samba / cifs-utils: mount.cifs file existence disclosure vulnerability

CVEs

• CVE-2012-1586

References

• https://access.redhat.com/security/updates/classification/#low

Red Hat Enterprise Linux Server 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
x86_64
cifs-utils-4.8.1-10.el6.x86_64.rpm	SHA-256: 5f093bfb2b46db8533c0006583edf03d721c8c03a354fa1efddc16ce4896fae5
cifs-utils-debuginfo-4.8.1-10.el6.x86_64.rpm	SHA-256: 0960bfd2cec9bd38bd78ad0c8dce1ff0bd1d8612819a54b2c176b16fea154222
i386
cifs-utils-4.8.1-10.el6.i686.rpm	SHA-256: c2cd6d4f8313ca012731cfa4a75b2a10dbe8af19aaf68c6b173dd65d6561990c
cifs-utils-debuginfo-4.8.1-10.el6.i686.rpm	SHA-256: bd194bbb8ac3437f82c2cbaaeb38558c4b05b601908fc47e39d151237003cf07

Red Hat Enterprise Linux Workstation 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
x86_64
cifs-utils-4.8.1-10.el6.x86_64.rpm	SHA-256: 5f093bfb2b46db8533c0006583edf03d721c8c03a354fa1efddc16ce4896fae5
cifs-utils-debuginfo-4.8.1-10.el6.x86_64.rpm	SHA-256: 0960bfd2cec9bd38bd78ad0c8dce1ff0bd1d8612819a54b2c176b16fea154222
i386
cifs-utils-4.8.1-10.el6.i686.rpm	SHA-256: c2cd6d4f8313ca012731cfa4a75b2a10dbe8af19aaf68c6b173dd65d6561990c
cifs-utils-debuginfo-4.8.1-10.el6.i686.rpm	SHA-256: bd194bbb8ac3437f82c2cbaaeb38558c4b05b601908fc47e39d151237003cf07

Red Hat Enterprise Linux Desktop 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
x86_64
cifs-utils-4.8.1-10.el6.x86_64.rpm	SHA-256: 5f093bfb2b46db8533c0006583edf03d721c8c03a354fa1efddc16ce4896fae5
cifs-utils-debuginfo-4.8.1-10.el6.x86_64.rpm	SHA-256: 0960bfd2cec9bd38bd78ad0c8dce1ff0bd1d8612819a54b2c176b16fea154222
i386
cifs-utils-4.8.1-10.el6.i686.rpm	SHA-256: c2cd6d4f8313ca012731cfa4a75b2a10dbe8af19aaf68c6b173dd65d6561990c
cifs-utils-debuginfo-4.8.1-10.el6.i686.rpm	SHA-256: bd194bbb8ac3437f82c2cbaaeb38558c4b05b601908fc47e39d151237003cf07

Red Hat Enterprise Linux for IBM z Systems 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
s390x
cifs-utils-4.8.1-10.el6.s390x.rpm	SHA-256: 1f67ccbb2fbef56dc9d5eb72fd026a0d8145e064705a922cca848225063d6481
cifs-utils-debuginfo-4.8.1-10.el6.s390x.rpm	SHA-256: dafa66587d329277d3b69696bbf68f2d24e79685cd885759559cc9bc42b753be

Red Hat Enterprise Linux for Power, big endian 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
ppc64
cifs-utils-4.8.1-10.el6.ppc64.rpm	SHA-256: 3a2307724602671adb66247e22bdbe42c379d95cb8bda06d64f2832b33b4ae08
cifs-utils-debuginfo-4.8.1-10.el6.ppc64.rpm	SHA-256: 1b4029e21a549c583e271402424e4eb91dd14eb59a9dfa246526461af1618fcf

Red Hat Enterprise Linux for Scientific Computing 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
x86_64
cifs-utils-4.8.1-10.el6.x86_64.rpm	SHA-256: 5f093bfb2b46db8533c0006583edf03d721c8c03a354fa1efddc16ce4896fae5
cifs-utils-debuginfo-4.8.1-10.el6.x86_64.rpm	SHA-256: 0960bfd2cec9bd38bd78ad0c8dce1ff0bd1d8612819a54b2c176b16fea154222

Red Hat Enterprise Linux Server from RHUI 6

SRPM
cifs-utils-4.8.1-10.el6.src.rpm	SHA-256: 2a1f4219a4b039b6ec3454a632ed237414ce411f77eafacd43c9d3245cbbf1ec
x86_64
cifs-utils-4.8.1-10.el6.x86_64.rpm	SHA-256: 5f093bfb2b46db8533c0006583edf03d721c8c03a354fa1efddc16ce4896fae5
cifs-utils-debuginfo-4.8.1-10.el6.x86_64.rpm	SHA-256: 0960bfd2cec9bd38bd78ad0c8dce1ff0bd1d8612819a54b2c176b16fea154222
i386
cifs-utils-4.8.1-10.el6.i686.rpm	SHA-256: c2cd6d4f8313ca012731cfa4a75b2a10dbe8af19aaf68c6b173dd65d6561990c
cifs-utils-debuginfo-4.8.1-10.el6.i686.rpm	SHA-256: bd194bbb8ac3437f82c2cbaaeb38558c4b05b601908fc47e39d151237003cf07