smbd_selinux(8) - Linux man page

Name

smbd_selinux - Security Enhanced Linux Policy for the smbd processes

Description

Security-Enhanced Linux secures the smbd processes via flexible mandatory access control.

The smbd processes execute with the smbd_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 smbd_t

Entrypoints

The smbd_t SELinux type can be entered via the "smbd_exec_t" file type. The default entrypoint paths for the smbd_t domain are the following:"

/usr/sbin/smbd

Process Types

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 ps

Policy governs the access confined processes have to files. SELinux smbd policy is very flexible allowing users to setup their smbd processes in as secure a method as possible.

The following process types are defined for smbd:

smbcontrol_t, smbmount_t, smbd_t

Note: semanage permissive -a smbd_t

can be used to make the process type smbd_t permissive. Permissive process types are not denied access by SELinux. AVC messages will still be generated.

Booleans

SELinux policy is customizable based on least access required. smbd policy is extremely flexible and has several booleans that allow you to manipulate the policy and run smbd with the tightest access possible.

If you want to allow samba to export ntfs/fusefs volumes, you must turn on the samba_share_fusefs boolean.

setsebool -P samba_share_fusefs 1

If you want to allow samba to share any file/directory read only, you must turn on the samba_export_all_ro boolean.

setsebool -P samba_export_all_ro 1

If you want to allow virt to manage cifs files, you must turn on the virt_use_samba boolean.

setsebool -P virt_use_samba 1

If you want to allow samba to create new home directories (e.g. via PAM), you must turn on the samba_create_home_dirs boolean.

setsebool -P samba_create_home_dirs 1

If you want to allow samba to share users home directories, you must turn on the samba_enable_home_dirs boolean.

setsebool -P samba_enable_home_dirs 1

If you want to allow samba to export NFS volumes, you must turn on the samba_share_nfs boolean.

setsebool -P samba_share_nfs 1

If you want to allow sanlock to manage cifs files, you must turn on the sanlock_use_samba boolean.

setsebool -P sanlock_use_samba 1

If you want to allow samba to run unconfined scripts, you must turn on the samba_run_unconfined boolean.

setsebool -P samba_run_unconfined 1

If you want to allow samba to act as the domain controller, add users, groups and change passwords, you must turn on the samba_domain_controller boolean.

setsebool -P samba_domain_controller 1

If you want to allow samba to share any file/directory read/write, you must turn on the samba_export_all_rw boolean.

setsebool -P samba_export_all_rw 1

If you want to allow samba to act as a portmapper, you must turn on the samba_portmapper boolean.

setsebool -P samba_portmapper 1

If you want to support SAMBA home directories, you must turn on the use_samba_home_dirs boolean.

setsebool -P use_samba_home_dirs 1

If you want to allow samba to modify public files used for public file transfer services. Files/Directories must be labeled public_content_rw_t, you must turn on the allow_smbd_anon_write boolean.

setsebool -P allow_smbd_anon_write 1

Sharing Files

If you want to share files with multiple domains (Apache, FTP, rsync, Samba), you can set a file context of public_content_t and public_content_rw_t. These context allow any of the above domains to read the content. If you want a particular domain to write to the public_content_rw_t domain, you must set the appropriate boolean.

Allow smbd servers to read the /var/smbd directory by adding the public_content_t file type to the directory and by restoring the file type.
semanage fcontext -a -t public_content_t "/var/smbd(/.*)?" restorecon -F -R -v /var/smbd
Allow smbd servers to read and write /var/tmp/incoming by adding the public_content_rw_t type to the directory and by restoring the file type. This also requires the allow_smbdd_anon_write boolean to be set.
semanage fcontext -a -t public_content_rw_t "/var/smbd/incoming(/.*)?"
restorecon -F -R -v /var/smbd/incoming
If you want to allow samba to modify public files used for public file transfer services. Files/Directories must be labeled public_content_rw_t., you must turn on the allow_smbd_anon_write boolean.
setsebool -P allow_smbd_anon_write 1

File Contexts

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 ls

Policy governs the access confined processes have to these files. SELinux smbd policy is very flexible allowing users to setup their smbd processes in as secure a method as possible.

The following file types are defined for smbd:

smbd_exec_t

- Set files with the smbd_exec_t type, if you want to transition an executable to the smbd_t domain.

smbd_keytab_t

- Set files with the smbd_keytab_t type, if you want to treat the files as kerberos keytab files.

smbd_tmp_t

- Set files with the smbd_tmp_t type, if you want to store smbd temporary files in the /tmp directories.

smbd_var_run_t

- Set files with the smbd_var_run_t type, if you want to store the smbd files under the /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.

Port Types

SELinux defines port types to represent TCP and UDP ports.

You can see the types associated with a port by using the following command:

semanage port -l

Policy governs the access confined processes have to these ports. SELinux smbd policy is very flexible allowing users to setup their smbd processes in as secure a method as possible.

The following port types are defined for smbd:

smbd_port_t
Default Defined Ports:: tcp 137-139,445

Managed Files

The SELinux process type smbd_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.

auth_cache_t

/var/cache/coolkey(/.*)?

ctdbd_var_lib_t

/etc/ctdb(/.*)?

/var/ctdb(/.*)?

/var/ctdbd(/.*)?

/var/lib/ctdbd(/.*)?

faillog_t

/var/log/btmp.*

/var/log/faillog.*

/var/log/tallylog.*

/var/run/faillock(/.*)?

initrc_tmp_t
initrc_var_run_t

/var/run/utmp

/var/run/random-seed

/var/run/runlevel.dir

/var/run/setmixer_flag

mnt_t

/mnt(/[^/]*)

/mnt(/[^/]*)?

/rhev(/[^/]*)?

/media(/[^/]*)

/media(/[^/]*)?

/etc/rhgb(/.*)?

/media/.hal-.*

/net

/afs

/misc

/rhev

nmbd_var_run_t

/var/run/nmbd.pid

/var/run/samba/nmbd.pid

/var/run/samba/messages.tdb

/var/run/samba/namelist.debug

/var/run/samba/unexpected.tdb

pcscd_var_run_t

/var/run/pcscd.events(/.*)?

/var/run/pcscd.pid

/var/run/pcscd.pub

/var/run/pcscd.comm

qemu_tmp_t
root_t

/initrd

samba_etc_t

/etc/samba(/.*)?

samba_log_t

/var/log/samba(/.*)?

samba_secrets_t

/etc/samba/smbpasswd

/etc/samba/passdb.tdb

/etc/samba/MACHINE.SID

/etc/samba/secrets.tdb

samba_share_t

use this label for random content that will be shared using samba

samba_var_t

/var/lib/samba(/.*)?

/var/cache/samba(/.*)?

/var/spool/samba(/.*)?

/var/nmbd/unexpected(/.*)?

smbd_tmp_t
smbd_var_run_t

/var/run/samba(/.*)?

/var/run/smbd.pid

/var/run/samba/smbd.pid

/var/run/samba/brlock.tdb

/var/run/samba/locking.tdb

/var/run/samba/gencache.tdb

/var/run/samba/sessionid.tdb

/var/run/samba/share_info.tdb

/var/run/samba/connections.tdb

tmp_t

/tmp

/usr/tmp

/var/tmp

/var/tmp/vi.recover

wtmp_t

/var/log/wtmp.*

Commands

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 port can also be used to manipulate the port definitions

semanage boolean can also be used to manipulate the booleans

system-config-selinux is a GUI tool available to customize SELinux policy settings.

Author

This manual page was auto-generated using sepolicy manpage by mgrepl.