tftpd_selinux(8) - Linux man page

Name

tftpd_selinux - Security Enhanced Linux Policy for the tftpd processes

Description

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

The tftpd processes execute with the tftpd_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 tftpd_t

Entrypoints

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

/usr/sbin/atftpd, /usr/sbin/in.tftpd

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 tftpd policy is very flexible allowing users to setup their tftpd processes in as secure a method as possible.

The following process types are defined for tftpd:

tftpd_t

Note: semanage permissive -a tftpd_t

can be used to make the process type tftpd_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. tftpd policy is extremely flexible and has several booleans that allow you to manipulate the policy and run tftpd with the tightest access possible.

If you want to allow tftp to modify public files used for public file transfer services, you must turn on the tftp_anon_write boolean.

setsebool -P tftp_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 tftpd servers to read the /var/tftpd 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/tftpd(/.*)?" restorecon -F -R -v /var/tftpd
Allow tftpd 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_tftpdd_anon_write boolean to be set.
semanage fcontext -a -t public_content_rw_t "/var/tftpd/incoming(/.*)?"
restorecon -F -R -v /var/tftpd/incoming
If you want to allow tftp to modify public files used for public file transfer services., you must turn on the tftp_anon_write boolean.
setsebool -P tftp_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 tftpd policy is very flexible allowing users to setup their tftpd processes in as secure a method as possible.

The following file types are defined for tftpd:

tftpd_exec_t

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

tftpd_var_run_t

- Set files with the tftpd_var_run_t type, if you want to store the tftpd files under the /run directory.

tftpdir_rw_t

- Set files with the tftpdir_rw_t type, if you want to treat the files as tftpdir read/write content.

tftpdir_t

- Set files with the tftpdir_t type, if you want to treat the files as tftpdir 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.

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 tftpd policy is very flexible allowing users to setup their tftpd processes in as secure a method as possible.

The following port types are defined for tftpd:

tftp_port_t
Default Defined Ports:: udp 69

Managed Files

The SELinux process type tftpd_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.

initrc_tmp_t

mnt_t

/mnt(/[^/]*)

/mnt(/[^/]*)?

/rhev(/[^/]*)?

/media(/[^/]*)

/media(/[^/]*)?

/etc/rhgb(/.*)?

/media/.hal-.*

/net

/afs

/misc

/rhev

root_t

/initrd

tftpd_var_run_t
tftpdir_rw_t

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

tmp_t

/tmp

/usr/tmp

/var/tmp

/var/tmp/vi.recover

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.