Security-Enhanced Linux secures the named processes via flexible mandatory access control.
The named processes execute with the named_t SELinux type. You can check if you have these processes running by executing the ps command with the -Z qualifier.
For example:
ps -eZ | grep named_t
The named_t SELinux type can be entered via the named_checkconf_exec_t, named_exec_t file types.
The default entrypoint paths for the named_t domain are the following:
/usr/sbin/named-checkconf, /usr/sbin/named, /usr/sbin/lwresd, /usr/sbin/unbound, /usr/sbin/named-sdb, /usr/sbin/named-pkcs11, /usr/sbin/unbound-anchor, /usr/sbin/unbound-control, /usr/sbin/unbound-checkconf
You can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux named policy is very flexible allowing users to setup their named processes in as secure a method as possible.
The following process types are defined for named:
named_t
Note: semanage permissive -a named_t can be used to make the process type named_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.
If you want to determine whether Bind can bind tcp socket to http ports, you must turn on the named_tcp_bind_http_port boolean. Disabled by default.
setsebool -P named_tcp_bind_http_port 1
If you want to determine whether Bind can write to master zone files. Generally this is used for dynamic DNS or zone transfers, you must turn on the named_write_master_zones boolean. Enabled by default.
setsebool -P named_write_master_zones 1
If you want to allow users to resolve user passwd entries directly from ldap rather then using a sssd server, you must turn on the authlogin_nsswitch_use_ldap boolean. Disabled by default.
setsebool -P authlogin_nsswitch_use_ldap 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
If you want to allow confined applications to run with kerberos, you must turn on the kerberos_enabled boolean. Enabled by default.
setsebool -P kerberos_enabled 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
If you want to allow confined applications to use nscd shared memory, you must turn on the nscd_use_shm boolean. Enabled by default.
setsebool -P nscd_use_shm 1
The SELinux process type named_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.
cluster_conf_t
/etc/cluster(/.*)?
cluster_var_lib_t
/var/lib/pcsd(/.*)?
/var/lib/cluster(/.*)?
/var/lib/openais(/.*)?
/var/lib/pengine(/.*)?
/var/lib/corosync(/.*)?
/usr/lib/heartbeat(/.*)?
/var/lib/heartbeat(/.*)?
/var/lib/pacemaker(/.*)?
cluster_var_run_t
/var/run/crm(/.*)?
/var/run/cman_.*
/var/run/rsctmp(/.*)?
/var/run/aisexec.*
/var/run/heartbeat(/.*)?
/var/run/corosync-qnetd(/.*)?
/var/run/corosync-qdevice(/.*)?
/var/run/corosync.pid
/var/run/cpglockd.pid
/var/run/rgmanager.pid
/var/run/cluster/rgmanager.sk
dnssec_trigger_var_run_t
/var/run/dnssec.*
ipa_var_lib_t
/var/lib/ipa(/.*)?
krb5_host_rcache_t
/var/cache/krb5rcache(/.*)?
/var/tmp/nfs_0
/var/tmp/DNS_25
/var/tmp/host_0
/var/tmp/imap_0
/var/tmp/HTTP_23
/var/tmp/HTTP_48
/var/tmp/ldap_55
/var/tmp/ldap_487
/var/tmp/ldapmap1_0
krb5_keytab_t
/etc/krb5.keytab
/etc/krb5kdc/kadm5.keytab
/var/kerberos/krb5kdc/kadm5.keytab
named_cache_t
/var/named/data(/.*)?
/var/lib/softhsm(/.*)?
/var/lib/unbound(/.*)?
/var/named/slaves(/.*)?
/var/named/dynamic(/.*)?
/var/named/chroot/var/tmp(/.*)?
/var/named/chroot/var/named/data(/.*)?
/var/named/chroot/var/named/slaves(/.*)?
/var/named/chroot/var/named/dynamic(/.*)?
named_log_t
/var/log/named.*
/var/named/chroot/var/log/named.*
named_tmp_t
named_var_run_t
/var/run/bind(/.*)?
/var/run/named(/.*)?
/var/run/unbound(/.*)?
/var/named/chroot/run/named.*
/var/named/chroot/var/run/named.*
/var/run/ndc
named_zone_t
/var/named(/.*)?
/var/named/chroot/var/named(/.*)?
root_t
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
You can see the context of a file using the -Z option to lsP Policy governs the access confined processes have to these files. SELinux named policy is very flexible allowing users to setup their named processes in as secure a method as possible.
EQUIVALENCE DIRECTORIES
named policy stores data with multiple different file context types under the /var/named 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 dirctory you would execute the following command:
semanage fcontext -a -e /var/named /srv/named
restorecon -R -v /srv/named
STANDARD FILE CONTEXT
SELinux defines the file context types for the named, if you wanted to store files with these types in a diffent paths, you need to execute the semanage command to sepecify alternate labeling and then use restorecon to put the labels on disk.
semanage fcontext -a -t named_zone_t '/srv/mynamed_content(/.*)?'
restorecon -R -v /srv/mynamed_content
Note: SELinux often uses regular expressions to specify labels that match multiple files.
The following file types are defined for named:
named_cache_t
- Set files with the named_cache_t type, if you want to store the files under the /var/cache directory.
named_checkconf_exec_t
- Set files with the named_checkconf_exec_t type, if you want to transition an executable to the named_checkconf_t domain.
named_conf_t
- Set files with the named_conf_t type, if you want to treat the files as named configuration data, usually stored under the /etc directory.
named_exec_t
- Set files with the named_exec_t type, if you want to transition an executable to the named_t domain.
named_initrc_exec_t
- Set files with the named_initrc_exec_t type, if you want to transition an executable to the named_initrc_t domain.
named_keytab_t
- Set files with the named_keytab_t type, if you want to treat the files as kerberos keytab files.
named_log_t
- Set files with the named_log_t type, if you want to treat the data as named log data, usually stored under the /var/log directory.
named_tmp_t
- Set files with the named_tmp_t type, if you want to store named temporary files in the /tmp directories.
named_unit_file_t
- Set files with the named_unit_file_t type, if you want to treat the files as named unit content.
named_var_run_t
- Set files with the named_var_run_t type, if you want to store the named files under the /run or /var/run directory.
named_zone_t
- Set files with the named_zone_t type, if you want to treat the files as named zone data.
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 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.