Re: why I have lost messages on boot even with very big backlog while I hunting only 2 syscalls?
On Wednesday, September 27, 2017 4:41:29 PM EDT Lev Olshvang wrote:
Hello list !
A very technical question
I have Ubuntu 16.10 Virtual Box , auditd 2.7.8
I have audit=1 parameter in grub.cfg
I see that /proc/cmdline indeed sees it
I see that auditd is started with PID 564
root 312 2 0 23:12 ? 00:00:00 [kauditd]
root 564 1 0 23:12 ? 00:00:00 /sbin/auditd
And I have 15 lost messages ???
auditctl -s
enabled 1
failure 1
pid 564
rate_limit 0
backlog_limit 16384
lost 15
backlog 0
backlog_wait_time 30
loginuid_immutable 0 unlocked
auditctl -l
-a always,exit -F arch=b64 -S execve,execveat -F key=exec
Do I understand correctly that auiditd is indeed started by systemd before
other services, except 2 that is listed in auditd.service dependencuies -
local-fs and some temp setup of systemd ?
Yes, it is started before most services. However. systemd-journal for some
reason feels obligated to enable auditing. And sometimes people put audit=1 on
the kernel command line. Either way, auditing is on way before auditd starts.
The audit logs have a 64 entry buffer by default. So, as the system boots
events pile up and eventually overflows the 64 entry limit.
The fix is to add another boot command option audit_backlog_limit=8192 or some
other suitable number. The test to check for this is to boot your system,
login and run auditctl -s. If you have just booted and lost events during
boot, this should fix it.
-Steve