Security-Enhanced Linux secures the cupsd processes via flexible mandatory access control.
The cupsd processes execute with the cupsd_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 cupsd_t
The cupsd_t SELinux type can be entered via the cupsd_exec_t file type.
The default entrypoint paths for the cupsd_t domain are the following:
/usr/sbin/hp-[^/]+, /usr/share/hplip/.*.py, /usr/lib/cups/backend/hp.*, /usr/bin/hpijs, /usr/sbin/cupsd, /usr/sbin/hpiod, /usr/sbin/cups-browsed
You can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux cupsd policy is very flexible allowing users to setup their cupsd processes in as secure a method as possible.
The following process types are defined for cupsd:
cupsd_config_t, cupsd_t, cupsd_lpd_t, cups_pdf_t
Note: semanage permissive -a cupsd_t can be used to make the process type cupsd_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 cups execmem/execstack, you must turn on the cups_execmem boolean. Disabled by default.
setsebool -P cups_execmem 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 cupsd_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.
anon_inodefs_t
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
cupsd_interface_t
/etc/cups/interfaces(/.*)?
cupsd_lock_t
cupsd_log_t
/var/log/hp(/.*)?
/var/log/cups(/.*)?
/usr/Brother/fax/.*.log.*
/var/log/turboprint.*
/usr/local/Brother/fax/.*.log.*
cupsd_rw_etc_t
/etc/printcap.*
/etc/cups/ppd(/.*)?
/usr/Brother/(.*/)?inf(/.*)?
/usr/Printer/(.*/)?inf(/.*)?
/usr/lib/bjlib(/.*)?
/var/lib/iscan(/.*)?
/var/cache/cups(/.*)?
/etc/cups/certs/.*
/etc/opt/Brother/(.*/)?inf(/.*)?
/etc/cups/lpoptions.*
/var/cache/foomatic(/.*)?
/usr/local/Brother/(.*/)?inf(/.*)?
/usr/local/Printer/(.*/)?inf(/.*)?
/etc/cups/cupsd.conf.*
/var/lib/cups/certs/.*
/opt/gutenprint/ppds(/.*)?
/opt/brother/Printers(.*/)?inf(/.*)?
/etc/cups/classes.conf.*
/etc/cups/printers.conf.*
/etc/cups/subscriptions.*
/etc/opt/brother/Printers/(.*/)?inf(/.*)?
/usr/local/linuxprinter/ppd(/.*)?
/var/cache/alchemist/printconf.*
/etc/alchemist/namespace/printconf(/.*)?
/etc/cups/certs
/etc/cups/ppds.dat
/var/lib/cups/certs
/usr/share/foomatic/db/oldprinterids
cupsd_tmp_t
cupsd_var_lib_t
/var/lib/hp(/.*)?
cupsd_var_run_t
/var/ccpd(/.*)?
/var/ekpd(/.*)?
/var/run/hp.*.pid
/var/run/hp.*.port
/var/run/cups(/.*)?
/var/run/hplip(/.*)
/var/turboprint(/.*)?
/var/run/ecblp0
faillog_t
/var/log/btmp.*
/var/log/faillog.*
/var/log/tallylog.*
/var/run/faillock(/.*)?
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
print_spool_t
/var/spool/lpd(/.*)?
/var/spool/cups(/.*)?
/var/spool/cups-pdf(/.*)?
root_t
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
samba_var_t
/var/nmbd(/.*)?
/var/lib/samba(/.*)?
/var/cache/samba(/.*)?
security_t
/selinux
snmpd_var_lib_t
/var/agentx(/.*)?
/var/net-snmp(/.*)
/var/lib/snmp(/.*)?
/var/net-snmp(/.*)?
/var/lib/net-snmp(/.*)?
/var/spool/snmptt(/.*)?
/usr/share/snmp/mibs/.index
usbfs_t
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 cupsd policy is very flexible allowing users to setup their cupsd processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the cupsd, 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 cupsd_unit_file_t '/srv/mycupsd_content(/.*)?'
restorecon -R -v /srv/mycupsd_content
Note: SELinux often uses regular expressions to specify labels that match multiple files.
The following file types are defined for cupsd:
cupsd_config_exec_t
- Set files with the cupsd_config_exec_t type, if you want to transition an executable to the cupsd_config_t domain.
cupsd_config_var_run_t
- Set files with the cupsd_config_var_run_t type, if you want to store the cupsd config files under the /run or /var/run directory.
cupsd_etc_t
- Set files with the cupsd_etc_t type, if you want to store cupsd files in the /etc directories.
cupsd_exec_t
- Set files with the cupsd_exec_t type, if you want to transition an executable to the cupsd_t domain.
cupsd_initrc_exec_t
- Set files with the cupsd_initrc_exec_t type, if you want to transition an executable to the cupsd_initrc_t domain.
cupsd_interface_t
- Set files with the cupsd_interface_t type, if you want to treat the files as cupsd interface data.
cupsd_lock_t
- Set files with the cupsd_lock_t type, if you want to treat the files as cupsd lock data, stored under the /var/lock directory
cupsd_log_t
- Set files with the cupsd_log_t type, if you want to treat the data as cupsd log data, usually stored under the /var/log directory.
cupsd_lpd_exec_t
- Set files with the cupsd_lpd_exec_t type, if you want to transition an executable to the cupsd_lpd_t domain.
cupsd_lpd_tmp_t
- Set files with the cupsd_lpd_tmp_t type, if you want to store cupsd lpd temporary files in the /tmp directories.
cupsd_lpd_var_run_t
- Set files with the cupsd_lpd_var_run_t type, if you want to store the cupsd lpd files under the /run or /var/run directory.
cupsd_rw_etc_t
- Set files with the cupsd_rw_etc_t type, if you want to store cupsd rw files in the /etc directories.
cupsd_tmp_t
- Set files with the cupsd_tmp_t type, if you want to store cupsd temporary files in the /tmp directories.
cupsd_unit_file_t
- Set files with the cupsd_unit_file_t type, if you want to treat the files as cupsd unit content.
cupsd_var_lib_t
- Set files with the cupsd_var_lib_t type, if you want to store the cupsd files under the /var/lib directory.
cupsd_var_run_t
- Set files with the cupsd_var_run_t type, if you want to store the cupsd 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 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.