4.4 - RHSA-2015:2417

Problem Description:

Updated autofs packages that fix one security issue, several bugs, and add one enhancement are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security 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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - x86_64 Red Hat Enterprise Linux Server (v. 7) - aarch64, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - x86_64

3. Description:

The autofs utility controls the operation of the automount daemon. The daemon automatically mounts file systems when in use and unmounts them when they are not busy.

It was found that program-based automounter maps that used interpreted languages such as Python used standard environment variables to locate and load modules of those languages. A local attacker could potentially use this flaw to escalate their privileges on the system. (CVE-2014-8169)

Note: This issue has been fixed by adding the "AUTOFS_" prefix to the affected environment variables so that they are not used to subvert the system. A configuration option ("force_standard_program_map_env") to override this prefix and to use the environment variables without the prefix has been added. In addition, warnings have been added to the manual page and to the installed configuration file. Now, by default the standard variables of the program map are provided only with the prefix added to its name.

Red Hat would like to thank the Georgia Institute of Technology for reporting this issue.

Notably, this update fixes the following bugs:

* When the "ls *" command was run in the root of an indirect mount, autofs attempted to literally mount the wildcard character (*) causing it to be added to the negative cache. If done before a valid mount, autofs then failed on further mount attempts inside the mount point, valid or not. This has been fixed, and wildcard map entries now function in the described situation. (BZ#1166457)

* When autofs encountered a syntax error consisting of a duplicate entry in a multimap entry, it reported an error and did not mount the map entry. With this update, autofs has been amended to report the problem in the log to alert the system administrator and use the last seen instance of the duplicate entry rather than fail. (BZ#1205600)

* In the ldap and sss lookup modules, the map reading functions did not distinguish between the "no entry found" and "service not available" errors. Consequently, when the "service not available" response was returned from a master map read, autofs did not update the mounts. An "entry not found" return does not prevent the map update, so the ldap and sss lookup modules were updated to distinguish between these two returns and now work as expected. (BZ#1233065)

In addition, this update adds the following enhancement:

* The description of the configuration parameter map_hash_table_size was missing from the autofs.conf(5) man page and its description in the configuration file comments was insufficient. A description of the parameter has been added to autofs.conf(5), and the configuration file comments have been updated. (BZ#1238573)

All autofs users are advised to upgrade to these updated packages, which contain backported patches to correct these issues and add this enhancement.

4. Solution:

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

5. Bugs fixed (https://bugzilla.redhat.com/):

1161474 - automount segment fault in parse_sun.so for negative parser tests 1166457 - Autofs unable to mount indirect after attempt to mount wildcard 1192565 - CVE-2014-8169 autofs: priv escalation via interpreter load path for program based automount maps 1201582 - autofs: MAPFMT_DEFAULT is not macro in lookup_program.c 1218045 - Similar but unrelated NFS exports block proper mounting of "parent" mount point 1233067 - autofs is performing excessive direct mount map re-reads 1233069 - Direct map does not expire if map is initially empty 1263508 - Heavy program map usage can lead to a hang