mscan_selinux(8)

💅 mscan_selinux(8) — the mscan SELinux policy page, bestie edition

okay so this is all about mscan_selinux, the SELinux policy that keeps the mscan processes in check. that's the whole vibe. let's get into it ✨

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🌸 NAME 🌸

mscan_selinux — the Security Enhanced Linux Policy for the mscan processes, no cap 💖

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🦋 DESCRIPTION 🦋

Security-Enhanced Linux secures the mscan processes via flexible mandatory access control. yes, mandatory — not the vibe where the process gets to choose. SELinux chooses for it 💅

The mscan processes execute with the mscan_t SELinux type. wanna check if you've got these processes running? just run the ps command with the -Z qualifier. easy.

For example:

ps -eZ | grep mscan_t

that's it, that's the check 🎀

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🚪 ENTRYPOINTS 🚪

The mscan_t SELinux type can be entered via the mscan_exec_t file type. so that's the doorway, and it's giving very exclusive-club energy 🔥

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

/usr/bin/MailScanner

one path, one icon 💅

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👑 PROCESS TYPES 👑

SELinux defines process types (domains) for each process running on the system. every process gets its own little domain, main character energy for everyone 🌈

You can see the context of a process using the -Z option to ps. go look, it's right there.

Policy governs the access confined processes have to files. the SELinux mscan policy is very flexible — it allows users to setup their mscan processes in as secure a method as possible. flexible and secure, we love that 🫶

The following process types are defined for mscan:

• mscan_t

Note: semanage permissive -a mscan_t can be used to make the process type mscan_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated. so like… it lets stuff through but it's still gonna talk about it 😭 the receipts stay.

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🎀 BOOLEANS 🎀

SELinux policy is customizable based on least access required. the mscan policy is extremely flexible and has several booleans that allow you to manipulate the policy and run mscan with the tightest access possible. tightest access = bestie behaviour, ngl 🔒

• 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

three booleans, three little switches, all documented, periodt ✨

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🗂️ MANAGED FILES 🗂️

The SELinux process type mscan_t can manage files labeled with the following file types. the paths listed are the default paths for these file types. and hey — the processes UID still need to have DAC permissions, so don't get it twisted 💀

antivirus_var_run_t

/run/clamd.*
/run/clamav.*
/run/amavis(d)?(/.*)?
/run/amavis(d)?/clamd.pid
/run/amavisd-snmp-subagent.pid

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

mqueue_spool_t

/var/spool/(client)?mqueue(/.*)?
/var/spool/mqueue.in(/.*)?

mscan_spool_t

/var/spool/MailScanner(/.*)?

mscan_tmp_t

(no default paths listed here — it's a mystery, an enigma, a vibe 🙈 but it's on the list!)

mscan_var_run_t

/run/MailScanner.pid

root_t

/sysroot/.aleph-version.json
/sysroot/ostree/deploy/.*-atomic/deploy(/.*)?
/
/initrd
/var/lib/ntp

that's the whole list, ten file types, zero skipped 💖

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🧚 FILE CONTEXTS 🧚

SELinux requires files to have an extended attribute to define the file type. it's not just a name situation, it's an attribute situation.

You can see the context of a file using the -Z option to ls. same -Z energy as before, but for files this time.

Policy governs the access confined processes have to these files. the SELinux mscan policy is very flexible — it allows users to setup their mscan processes in as secure a method as possible. (yes I said that already, it's still true 😌)

⭐ STANDARD FILE CONTEXT ⭐

SELinux defines the file context types for the mscan, so 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, both required, don't skip the second one 🎯

semanage fcontext -a -t mscan_exec_t '/srv/mscan/content(/.*)?'
restorecon -R -v /srv/mymscan_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 mscan:

mscan_etc_t

• Set files with the mscan_etc_t type, if you want to store mscan files in the /etc directories.

Paths:

/etc/MailScanner(/.*)?
/etc/sysconfig/MailScanner
/etc/sysconfig/update_spamassassin

mscan_exec_t

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

mscan_initrc_exec_t

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

mscan_spool_t

• Set files with the mscan_spool_t type, if you want to store the mscan files under the /var/spool directory.

mscan_tmp_t

• Set files with the mscan_tmp_t type, if you want to store mscan temporary files in the /tmp directories.

mscan_var_run_t

• Set files with the mscan_var_run_t type, if you want to store the mscan 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. so chcon = temporary little experiment, semanage fcontext + restorecon = the real, permanent commitment 🫶

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💻 COMMANDS 💻

a few more tools that do related things, all iconic in their own right:

• 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. a whole GUI, for the visual learners 🎨

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🌈 AUTHOR 🌈

This manual page was auto-generated using sepolicy manpage. a bot wrote it, and honestly? it ate. 🤖✨

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🦋 SEE ALSO 🦋

selinux(8), mscan(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 was mscan page, dated 26-10-06, living in section mscan_selinux(8) — go forth and label responsibly, mwah 💅💖