realmd_selinux(8)

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

💅 realmd_selinux(8) — the SELinux policy page for realmd, bestie edition ✨

okay so this is the manual page for realmd_selinux, and it's all about the SELinux Policy for the realmd processes. it lives in section 8 of the manual, and honestly? it's a whole vibe. let's get into it 🫶

🌸 NAME 🌸

realmd_selinux — the Security Enhanced Linux Policy for the realmd processes. that's it, that's the name, she's simple and she knows it 💅

✨ DESCRIPTION ✨

Security-Enhanced Linux secures the realmd processes via flexible mandatory access control. yes bestie, mandatory — not "if you feel like it" access control 😌

The realmd processes execute with the realmd_t SELinux type. wanna check if you've got these processes running? just run the ps command with the -Z qualifier. for example:

ps -eZ | grep realmd_t

look at that. iconic. look at your processes and their contexts, slay 🔥

🚪 ENTRYPOINTS 🚪

The realmd_t SELinux type can be entered via the realmd_exec_t file type. that's the door, that's how you get in 🚪✨

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

  • /usr/libexec/realmd
  • /usr/lib/realmd/realmd

write these down, they matter fr fr 📝

👑 PROCESS TYPES 👑

so SELinux defines process types (aka domains) for each process running on the system. yes, every single one has an identity. main character energy for everyone 🎀

You can see the context of a process using the -Z option to ps.

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

The following process types are defined for realmd:

  • realmd_t
Note: semanage permissive -a realmd_t can be used to make the process type realmd_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so like… she's not gonna stop you, but she WILL be taking notes 📝👀

🎚️ BOOLEANS 🎚️

SELinux policy is customizable based on least access required. realmd policy is extremely flexible and has several booleans that allow you to manipulate the policy and run realmd with the tightest access possible. tighten it up bestie 💜

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 deny user domains applications to map a memory region as both executable and writable, this is dangerous and the executable should be reported in bugzilla, you must turn on the deny_execmem boolean. Disabled by default.

setsebool -P deny_execmem 1

If you want to control the ability to mmap a low area of the address space, as configured by /proc/sys/vm/mmap_min_addr, you must turn on the mmap_low_allowed boolean. Disabled by default.

setsebool -P mmap_low_allowed 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

If you want to disable kernel module loading, you must turn on the secure_mode_insmod boolean. Disabled by default.

setsebool -P secure_mode_insmod 1

If you want to allow unconfined executables to make their heap memory executable. Doing this is a really bad idea. Probably indicates a badly coded executable, but could indicate an attack. This executable should be reported in bugzilla, you must turn on the selinuxuser_execheap boolean. Disabled by default.

setsebool -P selinuxuser_execheap 1

If you want to allow unconfined executables to make their stack executable. This should never, ever be necessary. Probably indicates a badly coded executable, but could indicate an attack. This executable should be reported in bugzilla, you must turn on the selinuxuser_execstack boolean. Disabled by default.

setsebool -P selinuxuser_execstack 1
🚨 bestie I cannot stress this enough: selinuxuser_execheap and selinuxuser_execstack are like, the "I'm about to do something cursed" booleans. and they're disabled by default for a REASON. periodt 💀

📂 MANAGED FILES 📂

The SELinux process type realmd_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 can't save you from plain old file permissions, sorry babe 😭).

file_type

all files on the system

like… all of them. the whole system. every file. the way that file_type is literally just "everything" 💀

🗂️ FILE CONTEXTS 🗂️

SELinux requires files to have an extended attribute to define the file type. yes, every file's got lore 🎀

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

🧚 STANDARD FILE CONTEXT 🧚

SELinux defines the file context types for the realmd, and 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. look:

semanage fcontext -a -t realmd_exec_t '/srv/realmd/content(/.*)?'
restorecon -R -v /srv/myrealmd_content
Note: SELinux often uses regular expressions to specify labels that match multiple files. regex princess behavior 💅

The following file types are defined for realmd:

realmd_exec_t

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

Paths:

  • /usr/libexec/realmd
  • /usr/lib/realmd/realmd

realmd_tmp_t

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

realmd_var_cache_t

  • Set files with the realmd_var_cache_t type, if you want to store the files under the /var/cache directory.

realmd_var_lib_t

  • Set files with the realmd_var_lib_t type, if you want to store the realmd files under the /var/lib 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, bestie — know the difference 🙈

🛠️ 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 girlies who like a little visual moment 🌈

🖋️ AUTHOR 🖋️

This manual page was auto-generated using sepolicy manpage. not me being auto-generated and still serving this hard 💅✨

👀 SEE ALSO 👀

go read those next, iykyk 📚🦋

okay and that's the whole page bestie!! 💖 this one came from realmd, dated 26-10-06, and it's the realmd_selinux(8) manual page — go forth and label responsibly, mwah 🎀🌸

📦 where this page comes from