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Since CoreOs 766, the auditing subsystem is partially integrated:

The audit subsystem has been enabled in the kernel and auditctl added to the image. Most audit events are ignored by default. The audit rules may be modified in /etc/audit/rules.d. Note that auditd is not included, journald is responsible for logging events instead although it is a best effort mechanism. Unlike with auditd based systems the kernel will not panic if journald fails to record an event for some reason.

I have tried the following in order to audit syscalls on both 899 and alpha 1000 CoreOs releases.

# starting a new periodic process:
$ while true; do echo "coreos ..." > /tmp/a.txt && sleep 5s; done &
[1] 4509

# get its pid and add a new audit rule:
$ sudo auditctl -a always,exit -F arch=b64 -S read,write,close,dup2,wait4 -F pid=4509

# wait 5 minutes and check if any audit related event was logged into by the journald:
$ journalctl | grep audit | wc
      0       0       0

Why can't I see any event that's logged by the journald?

The cn.ko is loaded properly and according the auditctl -l output the rule is set successfully. Though it looks like journald doesn't receive messages from the netlink interface.

I followed the following steps in order to enable debugging but it didn't give any hints either:

mkdir -p /etc/systemd/system/systemd-journald.service.d/

vim /etc/systemd/system/systemd-journald.service.d/10-debug.conf and filled it with following content:

[Service]
Environment=SYSTEMD_LOG_LEVEL=debug

And restart systemd-journald service:

systemctl daemon-reload
systemctl restart systemd-journald
dmesg | grep systemd-journald
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    I don't understand why you wouldn't ask this question of the CoreOS project directly coreos.com/community. Especially as this is a new feature and people in business environments (our target audience) don't usually use bleeding edge releases.
    – user9517
    Apr 10, 2016 at 6:00
  • 1
    @Iain I still don't know how or when CoreOS would make sense to use.
    – ewwhite
    Apr 11, 2016 at 1:38

1 Answer 1

5
+25

CoreOS ships with a set of default rules and is designed to be configured via the filesystem in /etc/audit/rules.d/. As you are trying to play with it interactively what you will want to do is clear the audit rules first as there is a rule at /etc/audit/rules.d/99-default.rules that silences all remaining rules.

Simply run audit -D to clear the rules and then your interactively added rules should start working.

FWIW, the rule from 99-default.rules that is causing trouble is -a exclude,always -F msgtype>0.

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  • As with many of the *.d directories, the contents are loaded in lexical order. Using 99- as the prefix ensures that rules can be easily added before (e.g. 00 through 98) as well as be added afterwards (e.g. beginning with alphabetic characters). For more information as to why that rule has specific mechanics read the man pages for audit.rules and auditctl. Apr 13, 2016 at 6:31

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