fwupd_selinux(8)

💖 fwupd_selinux(8) — the fwupd SELinux policy page, bestie edition 💖

Okay so this is the manual page for fwupd_selinux, and it's literally all about the Security Enhanced Linux Policy for the fwupd processes. Grab a snack, we're getting into it. 🍓

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✨ NAME ✨

fwupd_selinux — Security Enhanced Linux Policy for the fwupd processes, no cap.

🌸 DESCRIPTION 🌸

Security-Enhanced Linux secures the fwupd processes via flexible mandatory access control. It's giving very protective big sibling energy. 🫶

The fwupd processes execute with the fwupd_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 fwupd_t

Go off, ps. 💅

🦋 ENTRYPOINTS 🦋

The fwupd_t SELinux type can be entered via the fwupd_exec_t file type.

The default entrypoint paths for the fwupd_t domain are the following, bestie:

/usr/lib(exec)?/fwupd/fwupd, /usr/lib(exec)?/fwupd/fwupdoffline,
/usr/lib(exec)?/fwupd/fwupd-detect-cet

👑 PROCESS TYPES 👑

SELinux defines process types (domains) for each process running on the system. Every main character gets their own domain, honestly iconic.

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

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

The following process types are defined for fwupd:

• fwupd_t

Note: semanage permissive -a fwupd_t can be used to make the process type fwupd_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 taking receipts. 📝

🎀 BOOLEANS 🎀

SELinux policy is customizable based on least access required. fwupd policy is extremely flexible and has several booleans that allow you to manipulate the policy and run fwupd with the tightest access possible. Tightest access = the vibe check passed. ✅

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 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, and 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, and this executable should be reported in bugzilla — you must turn on the selinuxuser_execstack boolean. Disabled by default.

setsebool -P selinuxuser_execstack 1

🌈 MANAGED FILES 🌈

The SELinux process type fwupd_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 isn't out here doing everything, bestie.

• file_type — all files on the system. Yeah. All of them. 💀

💜 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 fwupd policy is very flexible, allowing users to set up their fwupd processes in as secure a method as possible.

⭐ STANDARD FILE CONTEXT ⭐

SELinux defines the file context types for the fwupd. 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 fwupd_exec_t '/srv/fwupd/content(/.*)?'
restorecon -R -v /srv/myfwupd_content

Note: SELinux often uses regular expressions to specify labels that match multiple files. Regex girlies stay winning. 🧚

The following file types are defined for fwupd:

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

Paths:

/var/cache/fwupd(/.*)?, /var/cache/app-info(/.*)?

• fwupd_cert_t — Set files with the fwupd_cert_t type, if you want to treat the files as fwupd certificate data.
• fwupd_exec_t — Set files with the fwupd_exec_t type, if you want to transition an executable to the fwupd_t domain.

Paths:

/usr/lib(exec)?/fwupd/fwupd, /usr/lib(exec)?/fwupd/fwupdoffline,
/usr/lib(exec)?/fwupd/fwupd-detect-cet

• fwupd_unit_file_t — Set files with the fwupd_unit_file_t type, if you want to treat the files as fwupd unit content.
• fwupd_var_lib_t — Set files with the fwupd_var_lib_t type, if you want to store the fwupd 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. Temporarily vs permanently is a whole different vibe, don't mix them up. 🙈

🔥 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. GUI besties rise. 🖥️✨

🫶 AUTHOR 🫶

This manual page was auto-generated using sepolicy manpage.

👀 SEE ALSO 👀

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

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That's the whole page, bestie — fwupd policy, version 26-10-06, dated 26-10-06 (yes the same, she's consistent 💅). Go forth and label responsibly. 🦋💖