Check_MK Werk 0978: Fix security issue with mk-job on Linux

ID: 0978 Title: Fix security issue with mk-job on Linux Component: Checks & Agents Level: 2 Class: Incompatible Change Version: 1.2.5i3 By use of symlinks or hardlinks normal users could inject files to be read with root permissions. This was due to the fact that <tt>/var/lib/check_mk_agent/job</tt> was installed with the permissions <tt>1777</tt>, just as <tt>/tmp</tt>. That way a normal user could have placed a symlink to a file there that is only readable by <tt>root</tt>. The content of that file would then appear in the agent output. This has been fixed by not longer using <tt>/var/lib/check_mk_agent/job</tt> directly, but by creating a separate subdirectory below that for each user. This is done by a new version of <tt>/usr/bin/mk-job</tt>, so please make sure that if you update the agent that you also update <tt>mk-job</tt>. Also you now have to create job subdirectories for non-<tt>root</tt> jobs manually. If you have a job running as user <tt>foo</tt>, then do: C+: RP:mkdir -p /var/lib/check_mk_agent/job RP:chown foo.foo /var/lib/check_mk_agent/job C-: