(RHSA-2015:2417) Moderate: autofs security, bug fix and enhancement update

ID RHSA-2015:2417
Type redhat
Reporter RedHat
Modified 2018-04-12T03:32:43


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.