Re: Writting to audit with an application

geckiv
2007-03-17T21:35:08Z

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Steve,
Thanks for the reply. I must have something wrong with my system as I
can't get it to work even running it as root. I get an error of:

FAILURE: errno = 22
Error writing audit file: Invalid argument
Error writing audit: Illegal seek

Also how do I set auditd to allow other process(s) running not as root
to write to the netlink/kernel ( i.e. set CAP_AUDIT_WRITE)? I could not
find any info on this. Also where do I find these trusted app examples?
Is this something I down loa the src of Linux and look for?

snip
-----
fd = audit_open();
if (fd < 0)
{
printf("audit open failure, errno = %d\n", errno);
}
else
{
printf("audit file opened, fd = %d\n", fd);
printf("attempting to write to audit log.\n");

snprintf(msg, sizeof(msg), "My mesg to audit");

if ((rc = audit_log_user_message(fd, 1101,
msg, NULL, NULL, NULL, 0)) > 0)
printf("SUCCESS: rc = %d\n", rc);
else
{
printf("FAILURE: errno = %d\n", errno);
perror( "Error writing audit file" );
printf( "Error writing audit: %s\n", strerror( errno ) );
}

Steve Grubb wrote:

>On Saturday 17 March 2007 14:54:54 geckiv wrote:
>
>
>>I was wondering if anyone had a good example of how to write to the
>>audit log on linux for a custom application wanting to log events.
>>
>>
>
>There's several examples in trusted apps. But its really simple to do. This is
>from aide:
>
>#ifdef WITH_AUDIT
> if(nadd!=0||nrem!=0||nchg!=0){
> int fd=audit_open();
> if (fd>=0){
> char msg[64];
>
> snprintf(msg, sizeof(msg), "added=%ld removed=%ld changed=%ld",
> nadd, nrem, nchg);
>
> if (audit_log_user_message(fd, AUDIT_ANOM_RBAC_INTEGRITY_FAIL,
> msg, NULL, NULL, NULL, 0)<=0)
>#ifdef HAVE_SYSLOG
> syslog(LOG_ERR, "Failed sending audit message:%s", msg);
>#else
> ;
>#endif
> close(fd);
> }
>
>Being that I don't know what your app is doing, I'd say that you should use
>the AUDIT_TRUSTED_APP event type. Also try to follow guidelines so that it
>can be parsed correctly by tools:
>
>http://people.redhat.com/sgrubb/audit/audit-parse.txt
>
>
>
>>Does it write to the demon then write to the /var/log/auit/audit.log?
>>
>>
>
>No, it sends it to the kernel which decides what to do with it.
>
>
>
>>Also how do yo set this up so not just any one or any process write to that
>>log?
>>
>>
>
>The audit system is intended to be high integrity, meaning that its not able
>to be written to by ordinary users. You have to have CAP_AUDIT_WRITE in order
>to write to the audit system.
>
>-Steve
>
>
>
>

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