Security-Enhanced Linux secures the cronjob processes via flexible mandatory access control.
The cronjob processes execute with the cronjob_t SELinux type. You can check if you have these processes running by executing the ps command with the -Z qualifier.
ps -eZ | grep cronjob_t
The cronjob_t SELinux type can be entered via the shell_exec_t, user_cron_spool_t file types.
The default entrypoint paths for the cronjob_t domain are the following:
/bin/d?ash, /bin/ksh.*, /bin/zsh.*, /usr/bin/d?ash, /usr/bin/ksh.*, /usr/bin/zsh.*, /bin/esh, /bin/bash, /bin/fish, /bin/mksh, /bin/sash, /bin/tcsh, /bin/yash, /bin/bash2, /usr/bin/esh, /sbin/nologin, /usr/bin/bash, /usr/bin/fish, /usr/bin/mksh, /usr/bin/sash, /usr/bin/tcsh, /usr/bin/yash, /usr/bin/bash2, /usr/sbin/sesh, /usr/sbin/smrsh, /usr/bin/scponly, /usr/libexec/sesh, /usr/sbin/nologin, /usr/bin/git-shell, /usr/sbin/scponlyc, /usr/libexec/sudo/sesh, /usr/bin/cockpit-bridge, /usr/libexec/cockpit-agent, /usr/libexec/git-core/git-shell, /var/spool/at(/.*)?, /var/spool/cron
You can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux cronjob policy is very flexible allowing users to setup their cronjob processes in as secure a method as possible.
The following process types are defined for cronjob:
Note: semanage permissive -a cronjob_t can be used to make the process type cronjob_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.
If you want to allow all domains to execute in fips_mode, you must turn on the fips_mode boolean. Enabled by default.
setsebool -P fips_mode 1
If you want to allow system to run with NIS, you must turn on the nis_enabled boolean. Disabled by default.
setsebool -P nis_enabled 1
The SELinux process type cronjob_t can manage files labeled with the following file types. The paths listed are the default paths for these file types. Note the processes UID still need to have DAC permissions.
semanage permissive can also be used to manipulate whether or not a process type is permissive.
semanage module can also be used to enable/disable/install/remove policy modules.
semanage boolean can also be used to manipulate the booleans
system-config-selinux is a GUI tool available to customize SELinux policy settings.