postgrey_selinux(8)

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

💅 postgrey_selinux(8) — the postgrey SELinux glow-up guide

Okay bestie, welcome to postgrey_selinux — the man page that tells you everything about the SELinux policy for the postgrey processes. Grab a snack, we're going in 🍓

✨ NAME ✨

postgrey_selinux — Security Enhanced Linux Policy for the postgrey processes. That's it, that's the whole vibe 🎀

🌸 DESCRIPTION 🌸

Security-Enhanced Linux secures the postgrey processes via flexible mandatory access control. Yes, mandatory. SELinux doesn't ask, it just decides. Iconic behavior honestly 👑

So here's the tea: the postgrey processes execute with the postgrey_t SELinux type. Wanna check if you've got these processes running? Run the ps command with the -Z qualifier, like this:

ps -eZ | grep postgrey_t

That's your vibe check right there 🔍

🦋 ENTRYPOINTS 🦋

You can enter the postgrey_t SELinux type via the postgrey_exec_t file type. Think of it as the doorway, the portal, the main character entrance 🚪✨

The default entrypoint paths for the postgrey_t domain are, literally just:

/usr/bin/postgrey

One path. That's the whole list. Slay.

👑 PROCESS TYPES 👑

SELinux defines process types (domains) for each process running on the system. Every process gets its own little identity, very demure, very mindful.

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

Policy governs the access confined processes have to files. The SELinux postgrey policy is very flexible, allowing users to setup their postgrey processes in as secure a method as possible. Flexible and secure, we love a multitasker 💅

The following process types are defined for postgrey:

  • postgrey_t
Note: semanage permissive -a postgrey_t can be used to make the process type postgrey_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. So it's chill mode, but the receipts are still being kept 😭

🔥 BOOLEANS 🔥

SELinux policy is customizable based on least access required. The postgrey policy is extremely flexible and has several booleans that allow you to manipulate the policy and run postgrey with the tightest access possible. Tightest access possible, no cap 🔒

Alright, here's the boolean rundown:

  • 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 allow all domains to execute in fips_mode, you must turn on the fips_mode boolean. Enabled by default.
setsebool -P fips_mode 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

Note that -P makes it persistent, bestie. You want it to stick around 💖

🌈 PORT TYPES 🌈

SELinux defines port types to represent TCP and UDP ports. Ports have types now, everybody say thank you SELinux 🫶

You can see the types associated with a port by using the following command:

semanage port -l

Policy governs the access confined processes have to these ports. The SELinux postgrey policy is very flexible, allowing users to setup their postgrey processes in as secure a method as possible.

The following port types are defined for postgrey:

  • postgrey_port_t

Default Defined Ports:

tcp 60000

That's port 60000, tcp, one single port, living its best life ✨

💜 MANAGED FILES 💜

The SELinux process type postgrey_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 needs to have DAC permissions. SELinux says yes, but your UID might still say no 🙈

  • cluster_conf_t
/etc/cluster(/.*)?
  • cluster_var_lib_t
/var/lib/pcsd(/.*)?
/var/lib/cluster(/.*)?
/var/lib/openais(/.*)?
/var/lib/pengine(/.*)?
/var/lib/corosync(/.*)?
/usr/lib/heartbeat(/.*)?
/var/lib/heartbeat(/.*)?
/var/lib/pacemaker(/.*)?
  • cluster_var_run_t
/run/crm(/.*)?
/run/cman_.*
/run/rsctmp(/.*)?
/run/aisexec.*
/run/heartbeat(/.*)?
/run/pcsd-ruby.socket
/run/corosync-qnetd(/.*)?
/run/corosync-qdevice(/.*)?
/run/pcsd.socket
/run/corosync.pid
/run/cpglockd.pid
/run/rgmanager.pid
/run/cluster/rgmanager.sk
  • krb5_host_rcache_t
/var/tmp/krb5_0.rcache2
/var/cache/krb5rcache(/.*)?
/var/tmp/nfs_0
/var/tmp/DNS_25
/var/tmp/host_0
/var/tmp/imap_0
/var/tmp/HTTP_23
/var/tmp/HTTP_48
/var/tmp/ldap_55
/var/tmp/ldap_487
/var/tmp/ldapmap1_0
  • postfix_spool_type — no default paths listed, it's mysterious like that 💀
  • postgrey_spool_t
/var/spool/postfix/postgrey(/.*)?
  • postgrey_var_lib_t
/var/lib/postgrey(/.*)?
  • postgrey_var_run_t
/run/postgrey(/.*)?
/run/postgrey.pid
  • root_t
/sysroot/.aleph-version.json
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
/var/lib/ntp

Yes, root_t literally includes /. The whole filesystem. Main character energy fr fr 🌍

🧚 FILE CONTEXTS 🧚

SELinux requires files to have an extended attribute to define the file type. It's like a little name tag for every file 🏷️

You can see the context of a file using the -Z option to ls.

Policy governs the access confined processes have to these files. The SELinux postgrey policy is very flexible, allowing users to setup their postgrey processes in as secure a method as possible.

⭐ STANDARD FILE CONTEXT ⭐

SELinux defines the file context types for the postgrey. 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. Two steps, bestie, don't skip the second one 😤

semanage fcontext -a -t postgrey_exec_t '/srv/postgrey/content(/.*)?'
restorecon -R -v /srv/mypostgrey_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 postgrey:

  • postgrey_etc_t — Set files with the postgrey_etc_t type, if you want to store postgrey files in the /etc directories.
  • postgrey_exec_t — Set files with the postgrey_exec_t type, if you want to transition an executable to the postgrey_t domain.
  • postgrey_initrc_exec_t — Set files with the postgrey_initrc_exec_t type, if you want to transition an executable to the postgrey_initrc_t domain.
  • postgrey_spool_t — Set files with the postgrey_spool_t type, if you want to store the postgrey files under the /var/spool directory.
  • postgrey_var_lib_t — Set files with the postgrey_var_lib_t type, if you want to store the postgrey files under the /var/lib directory.
  • postgrey_var_run_t — Set files with the postgrey_var_run_t type, if you want to store the postgrey files under the /run or /var/run directory.

Paths:

/run/postgrey(/.*)?, /run/postgrey.pid
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.

So like — chcon is the cute temporary tattoo, semanage fcontext is the real ink. Choose wisely 🎀

🛠️ COMMANDS 🛠️

Here's your toolbox, bestie:

  • 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 port can also be used to manipulate the port definitions.
  • semanage boolean can also be used to manipulate the booleans.
  • system-config-selinux is a GUI tool available to customize SELinux policy settings. A GUI! For when you want to point and click instead of typing 🖱️✨

💖 AUTHOR 💖

This manual page was auto-generated using sepolicy manpage. A robot wrote it, and honestly? It ate 🤖

🔗 SEE ALSO 🔗

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

Go read those next, you're gonna be so informed 🦋

And that's the whole page, bestie — this gem is from postgrey, dated 26-10-06, and it's the postgrey_selinux(8) manual, page 8 of 8, no more notes, you're free 💜✨

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