Security-Enhanced Linux secures the exim processes via flexible mandatory access control.
The exim processes execute with the exim_t SELinux type. You can check if you have these processes running by executing the ps command with the -Z qualifier.
ps -eZ | grep exim_t
The exim_t SELinux type can be entered via the exim_exec_t file type.
The default entrypoint paths for the exim_t domain are the following:
SELinux defines process types (domains) for each process running on the system
You can see the context of a process using the -Z option to psbP
Policy governs the access confined processes have to files. SELinux exim policy is very flexible allowing users to setup their exim processes in as secure a method as possible.
The following process types are defined for exim:
Note: semanage permissive -a exim_t can be used to make the process type exim_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.
SELinux policy is customizable based on least access required. exim policy is extremely flexible and has several booleans that allow you to manipulate the policy and run exim with the tightest access possible.
If you want to determine whether exim can connect to databases, you must turn on the exim_can_connect_db boolean. Disabled by default.
setsebool -P exim_can_connect_db 1
If you want to determine whether exim can create, read, write, and delete generic user content files, you must turn on the exim_manage_user_files boolean. Disabled by default.
setsebool -P exim_manage_user_files 1
If you want to determine whether exim can read generic user content files, you must turn on the exim_read_user_files boolean. Disabled by default.
setsebool -P exim_read_user_files 1
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
The SELinux process type exim_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.
SELinux requires files to have an extended attribute to define the file type.
You can see the context of a file using the -Z option to lsbP
Policy governs the access confined processes have to these files. SELinux exim policy is very flexible allowing users to setup their exim processes in as secure a method as possible.
exim policy stores data with multiple different file context types under the /var/run/exim[0-9]? directory. If you would like to store the data in a different directory you can use the semanage command to create an equivalence mapping. If you wanted to store this data under the /srv directory you would execute the following command:
semanage fcontext -a -e /var/run/exim[0-9]? /srv/exim[0-9]?
restorecon -R -v /srv/exim[0-9]?
STANDARD FILE CONTEXT
SELinux defines the file context types for the exim, if you wanted to store files with these types in a diffent paths, you need to execute the semanage command to specify alternate labeling and then use restorecon to put the labels on disk.
semanage fcontext -a -t exim_var_run_t '/srv/myexim_content(/.*)?'
restorecon -R -v /srv/myexim_content
Note: SELinux often uses regular expressions to specify labels that match multiple files.
The following file types are defined for exim:
- Set files with the exim_exec_t type, if you want to transition an executable to the exim_t domain.
- Set files with the exim_initrc_exec_t type, if you want to transition an executable to the exim_initrc_t domain.
- Set files with the exim_keytab_t type, if you want to treat the files as kerberos keytab files.
- Set files with the exim_log_t type, if you want to treat the data as exim log data, usually stored under the /var/log directory.
- Set files with the exim_spool_t type, if you want to store the exim files under the /var/spool directory.
- Set files with the exim_tmp_t type, if you want to store exim temporary files in the /tmp directories.
- Set files with the exim_var_lib_t type, if you want to store the exim files under the /var/lib directory.
- Set files with the exim_var_run_t type, if you want to store the exim files under the /run or /var/run directory.
Note: File context can be temporarily modified with the chcon command. If you want to permanently change the file context you need to use the semanage fcontext command. This will modify the SELinux labeling database. You will need to use restorecon to apply the labels.
semanage fcontext can also be used to manipulate default file context mappings.
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.
This manual page was auto-generated using sepolicy manpage .
selinux(8), exim(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8)