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/* audisp-example.c --
* Copyright 2012 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Steve Grubb <sgrubb@redhat.com>
*
* This is a sample program to demonstrate several concepts of how to
* write an audispd plugin using libauparse. It can be tested by using a
* file of raw audit records. You can generate the test file like:
*
* ausearch --start today --raw > test.log.
*
* Then you can test this app by: cat test.log | ./audisp-example
*
* It will print things to stdout. In a real program, you wouldn't
* do anything with stdout since that is likely to be pointing to /dev/null.
*
* Excluding some init/destroy items you might need to add to main, the
* event_handler function is the main place that you would modify to do
* things specific to your plugin.
*
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <sys/select.h>
#include <errno.h>
#include "libaudit.h"
#include "auparse.h"
/* Global Data */
static volatile int stop = 0;
static volatile int hup = 0;
static auparse_state_t *au = NULL;
/* Local declarations */
static void handle_event(auparse_state_t *au,
auparse_cb_event_t cb_event_type, void *user_data);
/*
* SIGTERM handler
*/
static void term_handler( int sig )
{
stop = 1;
}
/*
* SIGHUP handler: re-read config
*/
static void hup_handler( int sig )
{
hup = 1;
}
static void reload_config(void)
{
hup = 0;
}
int main(int argc, char *argv[])
{
char tmp[MAX_AUDIT_MESSAGE_LENGTH+1];
struct sigaction sa;
/* Register sighandlers */
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
/* Set handler for the ones we care about */
sa.sa_handler = term_handler;
sigaction(SIGTERM, &sa, NULL);
sa.sa_handler = hup_handler;
sigaction(SIGHUP, &sa, NULL);
/* Initialize the auparse library */
au = auparse_init(AUSOURCE_FEED, 0);
if (au == NULL) {
printf("audisp-example is exiting due to auparse init errors");
return -1;
}
auparse_add_callback(au, handle_event, NULL, NULL);
do {
fd_set read_mask;
struct timeval tv;
int retval;
/* Load configuration */
if (hup) {
reload_config();
}
do {
tv.tv_sec = 5;
tv.tv_usec = 0;
FD_ZERO(&read_mask);
FD_SET(0, &read_mask);
if (auparse_feed_has_data(au))
retval= select(1, &read_mask, NULL, NULL, &tv);
else
retval= select(1, &read_mask, NULL, NULL, NULL);
} while (retval == -1 && errno == EINTR && !hup && !stop);
/* Now the event loop */
if (!stop && !hup && retval > 0) {
if (fgets_unlocked(tmp, MAX_AUDIT_MESSAGE_LENGTH,
stdin)) {
auparse_feed(au, tmp, strnlen(tmp,
MAX_AUDIT_MESSAGE_LENGTH));
}
} else if (retval == 0)
auparse_flush_feed(au);
if (feof(stdin))
break;
} while (stop == 0);
/* Flush any accumulated events from queue */
auparse_flush_feed(au);
auparse_destroy(au);
if (stop)
printf("audisp-example is exiting on stop request\n");
else
printf("audisp-example is exiting on stdin EOF\n");
return 0;
}
/* This function shows how to dump a whole event by iterating over records */
static void dump_whole_event(auparse_state_t *au)
{
auparse_first_record(au);
do {
printf("%s\n", auparse_get_record_text(au));
} while (auparse_next_record(au) > 0);
printf("\n");
}
/* This function shows how to dump a whole record's text */
static void dump_whole_record(auparse_state_t *au)
{
printf("%s: %s\n", audit_msg_type_to_name(auparse_get_type(au)),
auparse_get_record_text(au));
printf("\n");
}
/* This function shows how to iterate through the fields of a record
* and print its name and raw value and interpretted value. */
static void dump_fields_of_record(auparse_state_t *au)
{
printf("record type %d(%s) has %d fields\n", auparse_get_type(au),
audit_msg_type_to_name(auparse_get_type(au)),
auparse_get_num_fields(au));
printf("line=%d file=%s\n", auparse_get_line_number(au),
auparse_get_filename(au) ? auparse_get_filename(au) : "stdin");
const au_event_t *e = auparse_get_timestamp(au);
if (e == NULL) {
printf("Error getting timestamp - aborting\n");
return;
}
/* Note that e->sec can be treated as time_t data if you want
* something a little more readable */
printf("event time: %u.%u:%lu, host=%s\n", (unsigned)e->sec,
e->milli, e->serial, e->host ? e->host : "?");
auparse_first_field(au);
do {
printf("field: %s=%s (%s)\n",
auparse_get_field_name(au),
auparse_get_field_str(au),
auparse_interpret_field(au));
} while (auparse_next_field(au) > 0);
printf("\n");
}
/* This function receives a single complete event at a time from the auparse
* library. This is where the main analysis code would be added. */
static void handle_event(auparse_state_t *au,
auparse_cb_event_t cb_event_type, void *user_data)
{
int type, num=0;
if (cb_event_type != AUPARSE_CB_EVENT_READY)
return;
/* Loop through the records in the event looking for one to process.
We use physical record number because we may search around and
move the cursor accidentally skipping a record. */
while (auparse_goto_record_num(au, num) > 0) {
type = auparse_get_type(au);
/* Now we can branch based on what record type we find.
This is just a few suggestions, but it could be anything. */
switch (type) {
case AUDIT_AVC:
dump_fields_of_record(au);
break;
case AUDIT_SYSCALL:
dump_whole_record(au);
break;
case AUDIT_USER_LOGIN:
break;
case AUDIT_ANOM_ABEND:
break;
case AUDIT_MAC_STATUS:
dump_whole_event(au);
break;
default:
break;
}
num++;
}
}
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