kernel_selinux(8)

💜 kernel_selinux(8) — the SELinux vibe check for kernel processes

okay so bestie, this is the kernel_selinux page from the SELinux Policy kernel manual, and it's literally all about how SELinux keeps an eye on your kernel processes. grab a snack, we're doing this 💅

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✨ NAME ✨

kernel_selinux — Security Enhanced Linux Policy for the kernel processes</p>

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🌸 DESCRIPTION 🌸

Security-Enhanced Linux secures the kernel processes via flexible mandatory access control. that's the whole assignment, no cap.

The kernel processes execute with the kernel_t SELinux type. wanna check if you've got these processes running? just run the ps command with the -Z qualifier, easy.

For example:

ps -eZ | grep kernel_t

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🦋 PROCESS TYPES 🦋

SELinux defines process types (domains) for each process running on the system. yes, each one, she's thorough.

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

Policy governs the access confined processes have to files. SELinux kernel policy is very flexible, allowing users to set up their kernel processes in as secure a method as possible. iconic behaviour honestly.

The following process types are defined for kernel:

kernel_generic_helper_t, kernel_t, kernel_systemctl_t

Note: semanage permissive -a kernel_t can be used to make the process type kernel_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so like, she stops blocking but she's still taking notes 📝

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🎀 BOOLEANS 🎀

SELinux policy is customizable based on least access required. kernel policy is extremely flexible and has several booleans that allow you to manipulate the policy and run kernel with the tightest access possible. main character energy fr fr.

• 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

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🌈 MANAGED FILES 🌈

The SELinux process type kernel_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. like, SELinux said yes but DAC can still say no 🫶

file_type

• all files on the system

yes. all of them. she contains multitudes 👑

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⭐ 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.

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🧚 AUTHOR 🧚

This manual page was auto-generated using sepolicy manpage. (the machines wrote this one bestie, we just gave it ✨flavour✨)

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💖 SEE ALSO 💖

selinux(8), kernel(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8), kernel_generic_helper_selinux(8), kernel_generic_helper_selinux(8), kernel_systemctl_selinux(8), kernel_systemctl_selinux(8)

(yes, a couple of those are listed twice in the original — I'm not gonna gaslight you about it 🙈)

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that's the whole page babes, love that for us 💅

kernel — 26-10-06 — kernel_selinux(8) 🍓