Re: A combined audit event message

[LC Bruzenak <lenny@magitekltd.com>]

On Fri, 2009-02-27 at 21:21 +0000, Matthew Booth wrote:
> I've been looking into tuning an audit events analysis tool which
> receives audit records over the network from a large number of systems.
> It turns out that the most significant overhead (by far) on the
> collection system is in stitching records from a single event back
> together. This has lead me to explore combining records on the host
> before sending them out. I'm currently intending to produce messages
> like this:
> 
> audit(1235768839.011:68): type=SYSCALL arch=40000003 syscall=5
> success=yes exit=3 a0=ad9c00 a1=8000 a2=1 a3=bfefd2d0 items=1 pid=6312
> auid=500 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
> comm="echo" exe="/bin/echo" | type=CWD  cwd="/root" | type=PATH
> name="/usr/lib/locale/locale-archive" flags=101 inode=126312 dev=03:01
> mode=0100644 ouid=0 ogid=0 rdev=00:00
> 

Matt,

If you don't mind indulging me a moment...I am very interested in the
ultimate goal you stated, "tuning an audit events analysis tool which
receives audit records over the network from a large number of systems",
since that is where I am headed...

For example I see the following from an ausearch :
...
----
node=jcdx type=PATH msg=audit(02/27/2009 15:32:41.747:2986) : item=0
name=/var/log/audit/audit.log inode=375 dev=fd:00 mode=file,600
ouid=root ogid=root rdev=00:00
obj=system_u:object_r:auditd_log_t:s15:c0.c1023 
node=jcdx type=CWD msg=audit(02/27/2009 15:32:41.747:2986) :  cwd=/root 
node=jcdx type=SYSCALL msg=audit(02/27/2009 15:32:41.747:2986) :
arch=x86_64 syscall=open success=yes exit=4 a0=7fffe635efeb a1=0
a2=f71a60 a3=f71a58 items=1 ppid=9014 pid=9492 auid=root uid=root
gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root
tty=pts1 ses=8 comm=ausearch exe=/sbin/ausearch
subj=root:auditadm_r:auditadm_t:s0-s15:c0.c1023 key=(null) 
node=jcdx type=AVC msg=audit(02/27/2009 15:32:41.747:2986) : avc:
denied  { read } for  pid=9492 comm=ausearch name=audit.log dev=dm-0
ino=375 scontext=root:auditadm_r:auditadm_t:s0-s15:c0.c1023
tcontext=system_u:object_r:auditd_log_t:s15:c0.c1023 tclass=file 
node=jcdx type=AVC msg=audit(02/27/2009 15:32:41.747:2986) : avc:
denied  { search } for  pid=9492 comm=ausearch name=audit dev=dm-0
ino=33885 scontext=root:auditadm_r:auditadm_t:s0-s15:c0.c1023
tcontext=system_u:object_r:auditd_log_t:s15:c0.c1023 tclass=dir 

And the corresponding raw file has this:
...
node=jcdx type=AVC msg=audit(1235770361.747:2986): avc:  denied
{ search } for  pid=9492 comm="ausearch" name="audit" dev=dm-0 ino=33885
scontext=root:auditadm_r:auditadm_t:s0-s15:c0.c1023
tcontext=system_u:object_r:auditd_log_t:s15:c0.c1023 tclass=dir
node=jcdx type=AVC msg=audit(1235770361.747:2986): avc:  denied
{ read } for  pid=9492 comm="ausearch" name="audit.log" dev=dm-0 ino=375
scontext=root:auditadm_r:auditadm_t:s0-s15:c0.c1023
tcontext=system_u:object_r:auditd_log_t:s15:c0.c1023 tclass=file
node=jcdx type=SYSCALL msg=audit(1235770361.747:2986): arch=c000003e
syscall=2 success=yes exit=4 a0=7fffe635efeb a1=0 a2=f71a60 a3=f71a58
items=1 ppid=9014 pid=9492 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0
egid=0 sgid=0 fsgid=0 tty=pts1 ses=8 comm="ausearch"
exe="/sbin/ausearch" subj=root:auditadm_r:auditadm_t:s0-s15:c0.c1023
key=(null)
node=jcdx type=CWD msg=audit(1235770361.747:2986):  cwd="/root"
node=jcdx type=PATH msg=audit(1235770361.747:2986): item=0
name="/var/log/audit/audit.log" inode=375 dev=fd:00 mode=0100600 ouid=0
ogid=0 rdev=00:00 obj=system_u:object_r:auditd_log_t:s15:c0.c1023

And what you are saying is that rather than use the ausearch equivalent
(or whatever tool which uses auparse library) on the receiving end, it
is more expedient to combine the record into one event prior to sending?
IIUC, is it because of the reduced amount of data flowing or less
processing needed on the receiving end (or both)?

Thx,
LCB.

-- 
LC (Lenny) Bruzenak
lenny@magitekltd.com