alsa_selinux(8)

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

💖 alsa_selinux — the whole vibe, bestie 💖

okay so this is the alsa_selinux(8) page, which honestly is a lot of words but it's all genuinely useful, so grab a snack and let's go ✨

🎀 NAME 🎀

alsa_selinux — Security Enhanced Linux Policy for the alsa processes 💅

🌸 DESCRIPTION 🌸

Security-Enhanced Linux secures the alsa processes via flexible mandatory access control. no cap, it's doing the most to keep things locked down 🫶

The alsa processes execute with the alsa_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 alsa_t

that's it, that's the check 🔍

✨ ENTRYPOINTS ✨

The alsa_t SELinux type can be entered via the alsa_exec_t file type.

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

  • /usr/bin/ainit
  • /usr/bin/salsa
  • /usr/bin/alsactl
  • /usr/bin/alsaunmute

those four are the doors into the domain, iykyk 🚪💫

👑 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 alsa policy is very flexible allowing users to setup their alsa processes in as secure a method as possible. it's giving customizable, honestly 💅

The following process types are defined for alsa:

  • alsa_t
Note: semanage permissive -a alsa_t can be used to make the process type alsa_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so like, it stops blocking but it's still gonna gossip about you in the logs 💀

🌈 BOOLEANS 🌈

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

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 system to run with NIS, you must turn on the nis_enabled boolean. Disabled by default.

setsebool -P nis_enabled 1

not me explaining booleans like they're a personality quiz, but here we are 🎀

🦋 MANAGED FILES 🦋

The SELinux process type alsa_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. ⚠️

💜 alsa_etc_rw_t

/etc/asound(/.*)?
/etc/alsa/pcm(/.*)?
/usr/share/alsa/pcm(/.*)?
/etc/asound.state
/etc/alsa/asound.state
/usr/share/alsa/alsa.conf

💜 alsa_lock_t

/run/lock/asound.state.lock

💜 alsa_tmp_t

(no default paths listed, she's mysterious like that 🙈)

💜 alsa_tmpfs_t

(also no default paths, keep it moving ✨)

💜 alsa_var_lib_t

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

💜 alsa_var_run_t

/run/alsactl.pid

💜 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

💜 sysfs_t

/sys(/.*)?

🔥 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 alsa policy is very flexible allowing users to setup their alsa processes in as secure a method as possible 💅

⭐ STANDARD FILE CONTEXT ⭐

SELinux defines the file context types for the alsa, 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. okay this part is lowkey important so pay attention 👀

semanage fcontext -a -t alsa_exec_t '/srv/alsa/content(/.*)?'
restorecon -R -v /srv/myalsa_content
Note: SELinux often uses regular expressions to specify labels that match multiple files. regex girlies rise 🌸

The following file types are defined for alsa:

🧚 alsa_etc_rw_t

  • Set files with the alsa_etc_rw_t type, if you want to treat the files as alsa etc read/write content.

Paths:

/etc/asound(/.*)?, /etc/alsa/pcm(/.*)?, /usr/share/alsa/pcm(/.*)?,
/etc/asound.state, /etc/alsa/asound.state,
/usr/share/alsa/alsa.conf

🧚 alsa_exec_t

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

Paths:

/usr/bin/ainit, /usr/bin/salsa, /usr/bin/alsactl,
/usr/bin/alsaunmute

🧚 alsa_home_t

  • Set files with the alsa_home_t type, if you want to store alsa files in the users home directory. home sweet home 🏠

🧚 alsa_lock_t

  • Set files with the alsa_lock_t type, if you want to treat the files as alsa lock data, stored under the /var/lock directory

🧚 alsa_tmp_t

  • Set files with the alsa_tmp_t type, if you want to store alsa temporary files in the /tmp directories.

🧚 alsa_tmpfs_t

  • Set files with the alsa_tmpfs_t type, if you want to store alsa files on a tmpfs file system.

🧚 alsa_unit_file_t

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

🧚 alsa_var_lib_t

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

🧚 alsa_var_run_t

  • Set files with the alsa_var_run_t type, if you want to store the alsa 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. temporary vs permanent, don't mix them up bestie 😭

🌟 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

system-config-selinux is a GUI tool available to customize SELinux policy settings. yes, a GUI, for the visual learners among us 🖥️✨

🫶 AUTHOR 🫶

This manual page was auto-generated using sepolicy manpage. the robots did this one, iconic of them 🤖💖

📚 SEE ALSO 📚

go read those too, they're all linked in the group chat fr fr 🦋

and that's the whole page bestie!! 🌈💖 source/version + date check: this is alsa, dated 26-10-06, and the page itself is alsa_selinux(8) — mwah, go forth and label things correctly 💅🎀

📦 where this page comes from