ftpd_selinux(8)

🦋 ftpd_selinux(8) — SELinux Policy ftpd 🦋

🌸 NAME 🌸

ftpd_selinux — Security Enhanced Linux Policy for the ftpd processes 💅

✨ DESCRIPTION ✨

Security-Enhanced Linux secures the ftpd processes via flexible mandatory access control. Like, that's the whole point, bestie — mandatory access control is doing the heavy lifting here.

The ftpd processes execute with the ftpd_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 ftpd_t

🚪 ENTRYPOINTS 🚪

The ftpd_t SELinux type can be entered via the ftpd_exec_t file type.

The default entrypoint paths for the ftpd_t domain are the following:

/usr/bin/ftpwho, /usr/bin/vsftpd, /usr/bin/in.ftpd, /usr/bin/proftpd,
/usr/bin/muddleftpd, /usr/kerberos/sbin/ftpd, /etc/cron.monthly/proftpd

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

The following process types are defined for ftpd:

• ftpd_t
• ftpdctl_t

Note: semanage permissive -a ftpd_t can be used to make the process type ftpd_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. 👀

🎚️ BOOLEANS 🎚️

SELinux policy is customizable based on least access required. ftpd policy is extremely flexible and has several booleans that allow you to manipulate the policy and run ftpd with the tightest access possible. So iconic of it, honestly.

• ftpd_connect_all_unreserved — if you want to determine whether ftpd can connect to all unreserved ports, you must turn on the ftpd_connect_all_unreserved boolean. Disabled by default.

setsebool -P ftpd_connect_all_unreserved 1

• ftpd_connect_db — if you want to determine whether ftpd can connect to databases over the TCP network, you must turn on the ftpd_connect_db boolean. Disabled by default.

setsebool -P ftpd_connect_db 1

• ftpd_full_access — if you want to determine whether ftpd can login to local users and can read and write all files on the system, governed by DAC, you must turn on the ftpd_full_access boolean. Disabled by default.

setsebool -P ftpd_full_access 1

• ftpd_use_cifs — if you want to determine whether ftpd can use CIFS used for public file transfer services, you must turn on the ftpd_use_cifs boolean. Disabled by default.

setsebool -P ftpd_use_cifs 1

• ftpd_use_fusefs — if you want to allow ftpd to use ntfs/fusefs volumes, you must turn on the ftpd_use_fusefs boolean. Disabled by default.

setsebool -P ftpd_use_fusefs 1

• ftpd_use_nfs — if you want to determine whether ftpd can use NFS used for public file transfer services, you must turn on the ftpd_use_nfs boolean. Disabled by default.

setsebool -P ftpd_use_nfs 1

• ftpd_use_passive_mode — if you want to determine whether ftpd can bind to all unreserved ports for passive mode, you must turn on the ftpd_use_passive_mode boolean. Disabled by default.

setsebool -P ftpd_use_passive_mode 1

• daemons_dontaudit_scheduling — if you want to dontaudit all daemons scheduling requests (setsched, sys_nice), you must turn on the daemons_dontaudit_scheduling boolean. Enabled by default.

setsebool -P daemons_dontaudit_scheduling 1

• fips_mode — 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

• kerberos_enabled — 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

• nis_enabled — 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

• use_nfs_home_dirs — if you want to support NFS home directories, you must turn on the use_nfs_home_dirs boolean. Enabled by default.

setsebool -P use_nfs_home_dirs 1

• use_samba_home_dirs — if you want to support SAMBA home directories, you must turn on the use_samba_home_dirs boolean. Disabled by default.

setsebool -P use_samba_home_dirs 1

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

The following port types are defined for ftpd:

• ftp_data_port_t — Default Defined Ports: tcp 20
• ftp_port_t — Default Defined Ports: tcp 21,989,990 and udp 989,990

🗂️ MANAGED FILES 🗂️

The SELinux process type ftpd_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. No cap. 🧢

• cifs_t — managed by ftpd_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

/run/crm(/.*)?
/run/cman_.*
/run/rsctmp(/.*)?
/run/aisexec.*
/run/heartbeat(/.*)?
/run/pcsd-ruby.socket
/run/corosync-qnetd(/.*)?
/run/corosync-qdevice(/.*)?
/run/pcsd.socket
/run/corosync.pid
/run/cpglockd.pid
/run/rgmanager.pid
/run/cluster/rgmanager.sk

• faillog_t

/var/log/btmp.*
/run/faillock(/.*)?
/var/log/faillog.*
/var/log/tallylog.*

• ftpd_lock_t

/run/lock/subsys/*.ftpd

• ftpd_tmp_t — managed by ftpd_t.
• ftpd_tmpfs_t — managed by ftpd_t.
• ftpd_var_run_t

/run/proftpd.*

• fusefs_t

/run/user/[0-9]+/gvfs

• httpd_user_content_t

/home/[^/]+/((www)|(web)|(public_html))(/.+)?

• initrc_var_run_t

/run/sysconfig(/.*)?
/run/utmp
/run/keymap
/run/numlock-on
/run/setleds-on
/run/runlevel.dir
/run/setmixer_flag
/run/bootsplashctl

• krb5_host_rcache_t

/var/tmp/krb5_0.rcache2
/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

• lastlog_t

/var/log/lastlog.*
/var/lib/lastlog(/.*)?

• nfs_t — managed by ftpd_t.
• non_security_file_type — managed by ftpd_t.
• root_t

/sysroot/.aleph-version.json
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
/var/lib/ntp

• security_t

/selinux

• user_home_t

/home/[^/]+/.+

• user_tmp_t

/run/tlog(/.*)?
/run/user/[^/]+
/dev/shm/mono.*
/tmp/.ICE-unix(/.*)?
/tmp/.X11-unix(/.*)?
/dev/shm/pulse-shm.*
/run/user
/tmp/.X0-lock
/tmp/hsperfdata_root
/var/tmp/hsperfdata_root
/home/[^/]+/tmp
/home/[^/]+/.tmp
/run/user/[0-9]+
/tmp/gconfd-[^/]+

• var_auth_t

/var/ace(/.*)?
/var/rsa(/.*)?
/var/lib/abl(/.*)?
/var/lib/rsa(/.*)?
/var/lib/pam_ssh(/.*)?
/var/lib/pam_shield(/.*)?
/var/opt/quest/vas/vasd(/.*)?
/var/lib/google-authenticator(/.*)?

• wtmpdb_journal_t

/var/lib/wtmpdb/wtmp.db-journal

• xferlog_t

/var/log/vsftpd.*
/var/log/xferlog.*
/var/log/proftpd(/.*)?
/var/log/xferreport.*
/var/log/muddleftpd.log.*
/var/log/proftpd.log
/usr/libexec/webmin/vsftpd/webalizer/xfer_log

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

🎀 STANDARD FILE CONTEXT 🎀

SELinux defines the file context types for the ftpd, if you wanted to store files with these types in a different 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 ftpd_exec_t '/srv/ftpd/content(/.*)?'
restorecon -R -v /srv/myftpd_content

Note: SELinux often uses regular expressions to specify labels that match multiple files.

The following file types are defined for ftpd:

• ftpd_etc_t — set files with the ftpd_etc_t type, if you want to store ftpd files in the /etc directories.
• ftpd_exec_t — set files with the ftpd_exec_t type, if you want to transition an executable to the ftpd_t domain.

Paths:

/usr/bin/ftpwho, /usr/bin/vsftpd, /usr/bin/in.ftpd,
/usr/bin/proftpd, /usr/bin/muddleftpd, /usr/kerberos/sbin/ftpd,
/etc/cron.monthly/proftpd

• ftpd_initrc_exec_t — set files with the ftpd_initrc_exec_t type, if you want to transition an executable to the ftpd_initrc_t domain.

Paths:

/etc/rc.d/init.d/vsftpd, /etc/rc.d/init.d/proftpd

• ftpd_keytab_t — set files with the ftpd_keytab_t type, if you want to treat the files as kerberos keytab files.
• ftpd_lock_t — set files with the ftpd_lock_t type, if you want to treat the files as ftpd lock data, stored under the /var/lock directory.
• ftpd_tmp_t — set files with the ftpd_tmp_t type, if you want to store ftpd temporary files in the /tmp directories.
• ftpd_tmpfs_t — set files with the ftpd_tmpfs_t type, if you want to store ftpd files on a tmpfs file system.
• ftpd_unit_file_t — set files with the ftpd_unit_file_t type, if you want to treat the files as ftpd unit content.

Paths:

/usr/lib/systemd/system/vsftpd.*, /usr/lib/systemd/system/proftpd.*

• ftpd_var_run_t — set files with the ftpd_var_run_t type, if you want to store the ftpd files under the /run or /var/run directory.
• ftpdctl_exec_t — set files with the ftpdctl_exec_t type, if you want to transition an executable to the ftpdctl_t domain.
• ftpdctl_tmp_t — set files with the ftpdctl_tmp_t type, if you want to store ftpdctl temporary files in the /tmp directories.

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. 💖

💖 SHARING FILES 💖

Okay so bestie, 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 contexts 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. That's the whole vibe check.

Wanna let ftpd servers read the /var/ftpd directory? Add the public_content_t file type to the directory and restore the file type. Slay:

semanage fcontext -a -t public_content_t "/var/ftpd(/.*)?"
restorecon -F -R -v /var/ftpd

Wanna let ftpd servers read and write /var/ftpd/incoming? Add the public_content_rw_t type to the directory and restore the file type. You also need to turn on the ftpd_anon_write boolean. Two-step icon behavior:

semanage fcontext -a -t public_content_rw_t "/var/ftpd/incoming(/.*)?"
restorecon -F -R -v /var/ftpd/incoming
setsebool -P ftpd_anon_write 1

And if you want to determine whether ftpd can modify public files used for public file transfer services, listen up: directories/files must be labeled public_content_rw_t, and you must turn on the ftpd_anon_write boolean. Like this:

setsebool -P ftpd_anon_write 1

---

🛠️ COMMANDS 🛠️

• semanage fcontext — can also be used to manipulate default file context mappings. Very main character of it.
• semanage permissive — can also be used to manipulate whether or not a process type is permissive. Vibes only.
• semanage module — can also be used to enable/disable/install/remove policy modules. It does it all, periodt.
• 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. A whole graphical bestie, if that's your thing 🎀.

---

✨ AUTHOR ✨

This manual page was auto-generated using sepolicy manpage. Not me writing it by hand with a glitter pen, but honestly close enough 💅.

---

👀 SEE ALSO 👀

Go check out selinux(8), ftpd(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), and setsebool(8). That's the reading list, no cap 📚✨.

---

This cutie page's source/version is ftpd, dated 26-10-06, and it's serving ftpd_selinux(8) — bye bestie, go label responsibly 🫶👑