xdm_uncon...d_selinux(8)

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

💅 xdm_unconfined_selinux(8) — the manual, but make it make sense

okay so bestie, welcome to the SELinux Policy xdm_unconfined page ✨ this is the xdm_uncon...d_selinux(8) situation and it's genuinely just here to explain how the xdm_unconfined processes get locked down 🔒

🎀 NAME

xdm_unconfined_selinux — the Security Enhanced Linux Policy for the xdm_unconfined processes. yep, that's it, that's the whole name. iconic.

🦋 DESCRIPTION

Security-Enhanced Linux secures the xdm_unconfined processes via flexible mandatory access control. no cap, that's the whole vibe — SELinux is out here running mandatory access control and it's flexible about it 💖

The xdm_unconfined processes execute with the xdm_unconfined_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 xdm_unconfined_t

like literally just run that and see who's living in xdm_unconfined_t land 👑

🌸 ENTRYPOINTS

The xdm_unconfined_t SELinux type can be entered via the xdm_unconfined_exec_t file type.

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

/etc/[mg]dm/Init(/.*)?
/etc/[mg]dm/PostLogin(/.*)?
/etc/[mg]dm/PreSession(/.*)?
/etc/[mg]dm/PostSession(/.*)?

those are your four doors in, periodt 🚪✨

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

The following process types are defined for xdm_unconfined:

  • xdm_unconfined_t
Note: semanage permissive -a xdm_unconfined_t can be used to make the process type xdm_unconfined_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so like, it won't block anything anymore, but it will still tell on you in the logs 💀

✨ BOOLEANS ✨

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

okay so here's the booleans list, each one turns on with setsebool -P <name> 1 and they're all disabled by default — flag that 🚩

  • deny_execmem — 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
  • mmap_low_allowed — 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
  • secure_mode_insmod — 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
  • selinuxuser_execheap — 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
  • selinuxuser_execstack — 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

like bestie please read those warnings, they are NOT decorative 😭

💜 MANAGED FILES

The SELinux process type xdm_unconfined_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 👀

yes. all files on the system. that's the whole list. no notes.

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

🌈 STANDARD FILE CONTEXT

SELinux defines the file context types for the xdm_unconfined, 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 xdm_unconfined_exec_t '/srv/xdm_unconfined/content(/.*)?'
restorecon -R -v /srv/myxdm_unconfined_content
Note: SELinux often uses regular expressions to specify labels that match multiple files. regex my beloved 🫶

The following file types are defined for xdm_unconfined:

xdm_unconfined_exec_t

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

Paths:

/etc/[mg]dm/Init(/.*)?
/etc/[mg]dm/PostLogin(/.*)?
/etc/[mg]dm/PreSession(/.*)?
/etc/[mg]dm/PostSession(/.*)?
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, know the difference 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. ooh, a GUI, fancy 🎀

🎀 AUTHOR

This manual page was auto-generated using sepolicy manpage .

(robot-written, human-approved ✨)

🔥 SEE ALSO

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

go read those too, iykyk 📚💖

that's the page!! this one came from the xdm_unconfined manual, dated 26-10-06 — mwah, stay labeled correctly out there 🦋👑💅

📦 where this page comes from