PAM_SELINUX(7)

✨ PAM_SELINUX — the manual page bestie 💅

okay so this is pam_selinux(7), part of the Linux-PAM Manual, and it's literally the module that sets your default security context. sit down, grab a strawberry, we're doing SELinux today 🍓

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🌸 NAME 🌸

pam_selinux — PAM module to set the default security context

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✨ SYNOPSIS ✨

pam_selinux.so [open] [close] [restore] [nottys] [debug] [verbose]
               [select_context] [env_params] [use_current_range]

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💖 DESCRIPTION 💖

pam_selinux is a PAM module that sets up the default SELinux security context for the next process that gets executed. iconic behavior, no cap.

When a new session is started, the open_session part of the module computes and sets up:

• the execution security context used for the next execve(2) call,
• the file security context for the controlling terminal,
• and the security context used for creating a new kernel keyring.

When the session is ended, the close_session part of the module restores the old security contexts — the ones that were in effect before the open_session part of the module changed them. we love a comeback arc 💖

⚠️ ngl, adding pam_selinux into the PAM stack might disrupt the behavior of other PAM modules that execute applications. to avoid that: pam_selinux.so open should be placed after such modules in the PAM stack, and pam_selinux.so close should be placed before them. and when that placement just isn't feasible? pam_selinux.so restore can be used to temporarily restore the original security contexts. slay 💅

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🎀 OPTIONS 🎀

• open — Only execute the open_session part of the module. just the opening act, nothing else.
• close — Only execute the close_session part of the module. closing time, you don't have to go home but you can't stay here.
• restore — In the open_session part of the module, temporarily restore the security contexts as they were before the previous call of the module. Another call of this module without the restore option will set up the new security contexts again. it's giving undo button 🫶
• nottys — Do not setup security context of the controlling terminal.
• debug — Turn on debug messages via syslog(3). we're nosy, we want the tea 💀
• verbose — Attempt to inform the user when security context is set. communication! we love her!
• select_context — Attempt to ask the user for a custom security context role. If MLS is on, ask also for sensitivity level.
• env_params — Attempt to obtain a custom security context role from the PAM environment. If MLS is on, obtain also the sensitivity level. This option and the select_context option are mutually exclusive. The respective PAM environment variables are SELINUX_ROLE_REQUESTED, SELINUX_LEVEL_REQUESTED, and SELINUX_USE_CURRENT_RANGE. The first two variables are self describing and the last one, if set to 1, makes the PAM module behave as if the use_current_range was specified on the command line of the module. iykyk.
• use_current_range — Use the sensitivity level of the current process for the user context instead of the default level. Also suppresses asking of the sensitivity level from the user or obtaining it from the PAM environment. main character energy, obviously ✨

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👑 MODULE TYPES PROVIDED 👑

Only the session module type is provided. one job, and she does it beautifully 💅

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🌈 RETURN VALUES 🌈

• PAM_SUCCESS — The security context was set successfully. ate, periodt 💖
• PAM_SESSION_ERR — Unable to get or set a valid context. 😭
• PAM_USER_UNKNOWN — The user is not known to the system. not me not knowing you 🙈
• PAM_BUF_ERR — Memory allocation error. the RAM said no 💀

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🦋 EXAMPLES 🦋

auth     required  pam_unix.so
session  required  pam_permit.so
session  optional  pam_selinux.so

look at her. three lines. flawless. ✨

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⭐ SEE ALSO ⭐

execve(2), tty(4), pam.d(5), pam(7), selinux(8)

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🧚 AUTHOR 🧚

pam_selinux was written by Dan Walsh <dwalsh@redhat.com>. thank you king 🫶

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so yeah, that's the whole page! this came out of the Linux-PAM Manual and the page itself is dated 09/03/2021, filed under PAM_SELINUX(7). go forth and set your contexts, bestie — you're gonna do amazing 🌸💖✨