avahi_selinux(8)

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version 20250627+git412.dbf877ab7 · 7 versions
, in opensuse-leap 16.0

💅 avahi_selinux — SELinux Policy for avahi (8)

okay so bestie, you opened avahi_selinux(8) and I'm gonna walk you through it like we're on FaceTime at 1am. this is the SELinux policy manual for the avahi processes — yes, the manual name is avahi_selinux, section 8. it's giving "security documentation but make it make sense." 🎀

✨ NAME ✨

avahi_selinux — Security Enhanced Linux Policy for the avahi processes 🦋

🌸 DESCRIPTION 🌸

Security-Enhanced Linux secures the avahi processes via flexible mandatory access control. that's the whole vibe. mandatory access control is the strict parent, flexible is the cool aunt — avahi gets both.

the avahi processes execute with the avahi_t SELinux type. you can check if you have these processes running by executing the ps command with the -Z qualifier. yes, -Z, that's the SELinux-flavored one, iykyk.

For example:

ps -eZ | grep avahi_t

run it, screenshot it, send it to the group chat. 💖

🚪 ENTRYPOINTS 🚪

The avahi_t SELinux type can be entered via the avahi_exec_t file type. that's the door, the bouncer checks your label, you're in.

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

/usr/bin/avahi-daemon, /usr/bin/avahi-autoipd, /usr/bin/avahi-dnsconfd

three doors, all iconic. 👑

🧚 PROCESS TYPES 🧚

SELinux defines process types (domains) for each process running on the system. every process has a little identity crisis and SELinux is the therapist.

You can see the context of a process using the -Z option to ps. told you. -Z again. it's consistent, we love her.

Policy governs the access confined processes have to files. SELinux avahi policy is very flexible allowing users to setup their avahi processes in as secure a method as possible. flexible and secure?? main character energy fr.

The following process types are defined for avahi:

  • avahi_t
Note: semanage permissive -a avahi_t can be used to make the process type avahi_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so it's not really a free pass, it's just a "we're watching, but we won't stop you" pass. 😭

🔥 BOOLEANS 🔥

SELinux policy is customizable based on least access required. avahi policy is extremely flexible and has several booleans that allow you to manipulate the policy and run avahi with the tightest access possible. booleans are literally the switches of the SELinux world and we're flipping them like light switches in a haunted house.

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

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 Apache to communicate with avahi service via dbus, you must turn on the httpd_dbus_avahi boolean. Enabled by default.

setsebool -P httpd_dbus_avahi 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

note the -P on all of these — that's the "make it stick across reboots" flag. without it your little change evaporates and we'd all be sad. 💅

🗂️ MANAGED FILES 🗂️

The SELinux process type avahi_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. SELinux will not carry you — DAC still gets a vote. periodt.

avahi_var_lib_t

/var/lib/avahi-autoipd(/.*)?

avahi_var_run_t

/run/avahi-daemon(/.*)?

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

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

root_t

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

like, yes, / is in there. the literal root directory. she's on the list. don't question it. 🙈

🎀 FILE CONTEXTS 🎀

SELinux requires files to have an extended attribute to define the file type. it's a little name tag, and the file wears it everywhere.

You can see the context of a file using the -Z option to ls. yes. -Z. third time. we're consistent girlies.

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

🦋 STANDARD FILE CONTEXT 🦋

SELinux defines the file context types for the avahi, 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 avahi_exec_t '/srv/avahi/content(/.*)?'
restorecon -R -v /srv/myavahi_content
Note: SELinux often uses regular expressions to specify labels that match multiple files. regex girlies rise.

The following file types are defined for avahi:

avahi_conf_t

  • Set files with the avahi_conf_t type, if you want to treat the files as avahi configuration data, usually stored under the /etc directory.

avahi_exec_t

  • Set files with the avahi_exec_t type, if you want to transition an executable to the avahi_t domain.

Paths:

/usr/bin/avahi-daemon, /usr/bin/avahi-autoipd, /usr/bin/avahi-dnsconfd

avahi_initrc_exec_t

  • Set files with the avahi_initrc_exec_t type, if you want to transition an executable to the avahi_initrc_t domain.

avahi_unit_file_t

  • Set files with the avahi_unit_file_t type, if you want to treat the files as avahi unit content.

avahi_var_lib_t

  • Set files with the avahi_var_lib_t type, if you want to store the avahi files under the /var/lib directory.

avahi_var_run_t

  • Set files with the avahi_var_run_t type, if you want to store the avahi 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. so: chcon = temporary tattoo, semanage fcontext = actual ink, restorecon = the artist doing the work. 💖

💅 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 boolean can also be used to manipulate the booleans. yes the booleans from earlier. they have a whole command. she's multifaceted.

system-config-selinux is a GUI tool available to customize SELinux policy settings. a GUI!! for when you want to click instead of type. no shame. 🌈

👑 AUTHOR 👑

This manual page was auto-generated using sepolicy manpage. a robot wrote this and honestly? she ate.

💜 SEE ALSO 💜

selinux(8), avahi(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8)

and that's the page bestie!! 🫶 this edition came from avahi, dated 26-10-06, and it's filed under avahi_selinux(8) — go forth, label your files, and remember: -Z is your best friend forever. ⭐💖

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