On Saturday, September 9, 2017 4:41:19 PM EDT Laurent Bigonville wrote: > Le 09/09/17 à 16:22, Steve Grubb a écrit : > > On Saturday, September 9, 2017 6:02:02 AM EDT Laurent Bigonville wrote: > >> Le 11/07/17 à 00:23, Paul Moore a écrit : > >>> On Mon, Jul 10, 2017 at 4:01 PM, Laurent Bigonville <[email protected]> > > wrote: > >>>> Le 10/07/17 à 18:00, Paul Moore a écrit : > >>>>> On Mon, Jul 10, 2017 at 10:59 AM, Laurent Bigonville > >>>>> <[email protected]> wrote: > >>>>>> Hi, > >>>>>> > >>>>>> With 4.11.6 (that has been uploaded in debian unstable) I get a lot > >>>>>> of messages in dmesg like > >>>>>> > >>>>>> [100052.120468] audit: audit_lost=66041 audit_rate_limit=0 > >>>>>> audit_backlog_limit=8192 > >>>>>> [100052.120470] audit: kauditd hold queue overflow > >>>>>> > >>>>>> And it also seems that the messages are not stored in auditd logs > >>>>>> anymore. > >>>>>> > >>>>>> https://git.kernel.org/linus/264d509637d95f9404e52ced5003ad352e0f6a26 > >>>>>> seems to be included in this release > >>>>>> > >>>>>> Any idea? > >>>>> > >>>>> I'm going to assume that your backlog limit is set to a sane value for > >>>>> your system's configuration, so that leaves me with two commits that > >>>>> may be of interest: > >>>>> > >>>>> * 1df30f8264b8 ("audit: fix the RCU locking for the auditd_connection > >>>>> structure") > >>>>> > >>>>> This was a manual backport of a v4.12 patch to v4.11, looking now, I > >>>>> see it should be in +v4.11.5 so that probably isn't your problem ... > >>>>> > >>>>> * c81be52a3ac0 ("audit: fix a race condition with the auditd tracking > >>>>> code") > >>>>> > >>>>> This patch is relatively new and was just sent up to Linus during the > >>>>> next merge window; it's a race condition fix so reproducing it can be > >>>>> tricky, although it may be easily reproducible on your system at the > >>>>> moment (luck you!). If you aren't in a position to apply the patch, > >>>>> the workaround is rather simple: restart auditd. > >>>>> > >>>>> If none of the above works, let me know, but I strongly suspect you're > >>>>> tripping over the race condition fixed in that last patch. > >>>> > >>>> I didn't test the patch yet, but I restarted the auditd daemon 2 times > >>>> and after that the queue has been flushed and I got all the message since > >>>> this noon in the audit logs. > >>> > >>> That sounds right; I'm guessing the patch above should be a more > >>> permanent fix. > >> > >> The patch should be applied in 4.13-rc7 right? > >> > >> It seems to fix the main issue (all the audit messages being logged in > >> dmesg) but I can still see from time to time the following message: > >> > >> [ 14.747565] audit: audit_lost=59 audit_rate_limit=0 > >> audit_backlog_limit=64 [ 14.747566] audit: kauditd hold queue overflow > > > > That is a very low backlog_limit. Is this during boot? > > Yes that's during boot (64 is the kernel's default) > > In my audit.rules I have '-b 8192'
OK. I blogged about this issue back in May: http://security-plus-data-science.blogspot.com/2017/05/a-suggested-change-for-rhel-7-disa-stig.html TL;DR, you have to set a boot command line option audit_backlog_limit=8192. I'm also starting to wonder if we can set the backlog to 6144 now that auditd runs much faster (~90x). -Steve -- Linux-audit mailing list [email protected] https://www.redhat.com/mailman/listinfo/linux-audit
