Early processes (daemons) do not report audit events

Sun Sep 13 15:58:26 UTC 2015

On 15/09/11, Kangkook Jee wrote:
> Hi Richard,

Hi Kangkook,

> I also did the same experiment for the latest distributions of Fedora
> core and Debian and here’s the results.
> 
> Fedora-22 (64-bit, 4.0.4-301.fc22.x86_64): Problem reproduced.
> Debian-8 (64-bit, 3.16.0-4-amd64): Problem reproduced
> 
> Btw, Burn Alting (burn at swtf.dyndns.org) suggested me to append audit=1
> to kernel flag. I added the option to boot-loader (grub) and problem
> went away. 

On all systems?  This is expected behaviour.  Sorry I was not more
explicit in asking you to test that.  I guess it was implied by asking
what the settings for the kernel command line were.

Now the surprising bit is that CentOS does not demonstrate the problem
without audit=1 in the command line, which leads me to wonder if they
have set "u32             audit_enabled = 1;" around line 83 of
kernel/audit.c in their kernel source.  It would surprise me if they
did, but it would not be completely unreasonable.

> Regards, Kangkook
> 
> > On Sep 11, 2015, at 12:24 PM, Richard Guy Briggs <rgb at redhat.com> wrote:
> > On 15/09/11, Kangkook Jee wrote:
> >> From the previous reply, I think I misunderstood your question regarding kernel command line. 
> >> Here’s "cat /proc/cmdline” results for distributions that I’ve experimented. 
> >> 
> >> Ubuntu 14.04 (64-bit): 
> >>    BOOT_IMAGE=/boot/vmlinuz-3.13.0-58-generic root=UUID=7505f862-ce46-49e5-9d1c-e4e307844889 ro text quiet splash vt.handoff=7
> >> 
> >> Ubuntu 12.04 (64-bit): 
> >>    BOOT_IMAGE=/boot/vmlinuz-3.13.0-32-generic root=UUID=5be789be-9b0c-463e-bd18-42bfa79fb24c ro quiet splash
> >> 
> >> CentOS 7 (64-bit): 
> >>    BOOT_IMAGE=/vmlinuz-3.10.0-229.el7.x86_64 root=/dev/mapper/centos-root ro rd.lvm.lv=centos/root rd.lvm.lv=centos/swap crashkernel=auto rhgb quiet LANG=en_US.UTF-8
> >> 
> >> CentOS 6 (64-bit): 
> >>    ro root=UUID=a7d44560-adcc-4000-9584-8b9fcf2afd74 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=129M at 0M  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
> >> 
> >> I don’t see any audit=<value> entries from all examples above. 
> > 
> > Yes, this is what I was seeking from you.  And you are correct, none of
> > them have audit=1 as I was hoping from at least CentOS.  There is a
> > chance that the CentOS kernel was compiled with audit=1 hardcoded, but I
> > think that is a pretty small chance...
> > 
> > I'll have to look at this closer...  But any Debian and Fedora data
> > points that you can provide would certainly be useful.
> > 
> >> /Kangkook
> >> 
> >>> On Sep 11, 2015, at 5:50 AM, Richard Guy Briggs <rgb at redhat.com> wrote:
> >>> 
> >>> On 15/09/10, Kangkook Jee wrote:
> >>>> Hi all,
> >>>> 
> >>>> I debugged a bit further to identify distributions that are affected by the issue.
> >>>> I repeated the same experiment with sshd from 3 more distributions.
> >>>> 
> >>>> CentOS Linux release 7.1.1503 (64-bit, 3.10.0-229.el7.x86_64): Problem NOT reproduced
> >>>> CentOS release 6.6 (64-bit, 2.6.32-504.el6.x86_64): Problem NOT reproduced
> >>>> Ubuntu 12.04.5 LTS (64-bit, 3.13.0-32-generic): Problem reproduced
> >>> 
> >>> For each of these examples, what is the value of the kernel command line
> >>> "audit=<value>" if it is even present?  It is possible that the CentOS
> >>> examples include "audit=1" while Ubuntu omits the line.  "cat
> >>> /proc/cmdline" should tell you the answer.
> >>> 
> >>>> After all, Ubuntu family are affected by the issue and I could confirm
> >>>> that results are inconsistent across two different distribution
> >>>> families. 
> >>> 
> >>> I would be curious what your results are with a recent Debian and with a
> >>> recent Fedora.
> >>> 
> >>>> If you can let us know how can we workaround the issue, it will be a great help.
> >>>> 
> >>>> Regards, Kangkook
> >>>> 
> >>>> 
> >>>>> On Sep 9, 2015, at 11:50 PM, Kangkook Jee <aixer77 at gmail.com> wrote:
> >>>>> 
> >>>>> Dear all,
> >>>>> 
> >>>>> We are developing custom user space audit agent to gather system wide system
> >>>>> call trace. While experimenting with various programs, we found out that
> >>>>> processes (daemons) that started early (along with the system bootstrapping) do
> >>>>> not report any audit events at all. These processes typically fall into PID
> >>>>> range of less than 2000. Here’s how I reproduced the symptom with sshd daemon.
> >>>>> 
> >>>>> 1. Reboot the system
> >>>>> 
> >>>>> 2. Add and enable audit events
> >>>>>  # /sbin/auditctl -a exit,always -F arch=b64 -S clone -S close -S creat -S dup
> >>>>>         -S dup2 -S dup3 -S execve -S exit -S exit_group -S fork -S open -S openat 
> >>>>>         -S unlink -S unlinkat -S vfork -S 288 -S accept -S bind -S connect 
> >>>>>         -S listen -S socket -S socketpair
> >>>>>  # /sbin/auditctl -e1 -b 102400
> >>>>> 
> >>>>> 3. Connect to the system via ssh
> >>>>>   Audit messages generated only from child processes and none are seen from
> >>>>>   the original daemon.
> >>>>> 
> >>>>> 4. Restart sshd 
> >>>>>   # restart ssh
> >>>>> 
> >>>>> 5. Connect again to the system via ssh
> >>>>>  Now, we see audit messages from both parent and child processes.
> >>>>> 
> >>>>> I did the experiment from Ubuntu 14.04.2 LTS distribution (64-bit, kernel
> >>>>> version 3.13.0-58-generic).
> >>>>> 
> >>>>> I first wonder whether this is intended behavior of audit framework or
> >>>>> not. If it is intended, I also want to know how can we configure auditd
> >>>>> differently to capture system calls from all processes. 
> >>>>> 
> >>>>> Thanks a lot for your help in advance!
> >>>>> 
> >>>>> Regards, Kangkook
> >>> 
> >>> - RGB
> > 
> > - RGB

- RGB

--
Richard Guy Briggs <rbriggs at redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
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