install_selinux(8)

💅 install_selinux(8) — the SELinux glow-up for your install processes

okay so bestie, welcome to the install_selinux manual page — it lives in section 8 of the SELinux Policy install manual, and it's literally all about keeping your install processes safe and iconic. 🎀

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✨ NAME ✨

install_selinux — Security Enhanced Linux Policy for the install processes. yes, that's the whole vibe. 💜

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🌸 SYNOPSIS 🌸

this page is pure policy documentation, no cap — read on for the whole story. 🦋

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🔥 DESCRIPTION 🔥

Security-Enhanced Linux secures the install processes via flexible mandatory access control. it's giving very serious security energy and honestly? obsessed. 💅

The install processes execute with the install_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 install_t

that's it. that's the vibe check. go run it, i'll wait. 🫶

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🚪 ENTRYPOINTS 🚪

The install_t SELinux type can be entered via the install_exec_t file type.

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

/usr/bin/bootc, /usr/bin/ostree, /usr/bin/anaconda, /usr/bin/rpm-ostree,
/usr/bin/initial-setup, /usr/libexec/rpm-ostreed,
/usr/libexec/anaconda/anaconda-yum

these are the doors into the domain, bestie. know them. 🚪✨

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

The following process types are defined for install:

• install_t

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

so like. permissive means the denials still get logged, they just don't get blocked. it's the "we see you, we're just not stopping you" setting. 🙈

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🎚️ BOOLEANS 🎚️

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

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 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

fr fr, those last two are big yikes territory. like, if you're flipping them on, something's already wrong and it should go in bugzilla. 😭

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📂 MANAGED FILES 📂

The SELinux process type install_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.

file_type

all files on the system

which is, uh, literally everything. slay i guess. 💀

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

🎀 STANDARD FILE CONTEXT 🎀

SELinux defines the file context types for the install, 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 install_exec_t '/srv/install/content(/.*)?'
restorecon -R -v /srv/myinstall_content

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

The following file types are defined for install:

install_exec_t

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

Paths:

/usr/bin/bootc, /usr/bin/ostree, /usr/bin/anaconda, /usr/bin/rpm-ostree,
/usr/bin/initial-setup, /usr/libexec/rpm-ostreed,
/usr/libexec/anaconda/anaconda-yum

install_var_run_t

• Set files with the install_var_run_t type, if you want to store the install 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 labeling is the classic situationship — chcon is the fling, semanage fcontext + restorecon is the committed relationship. choose wisely. 💜

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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.

the whole semanage family is here to help you, bestie. use them. 🫶✨

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✍️ AUTHOR ✍️

This manual page was auto-generated using sepolicy manpage .

(nope, i didn't hand-write this one — it's 100% auto-generated, and honestly? the robot ate. 🤖💅)

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👀 SEE ALSO 👀

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

go read those too, iykyk. 🦋

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and that's the whole page, bestie! this one's from the install manual, dated 26-10-06, and it's the install_selinux(8) page living in section 8 — mwah, take care of your install processes and stay secure out there. 💖🎀✨