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/*
* Copyright 2012, Samsung Telecommunications of America
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Written by William Roberts <w.roberts@sta.samsung.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdarg.h>
#include <stdint.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <cutils/klog.h>
#include <private/android_filesystem_config.h>
#include <linux/capability.h>
#include <linux/prctl.h>
#include "auditd.h"
#include "libaudit.h"
#include "audit_log.h"
/*
* TODO:
* Just Ideas:
* 1. Add a socket interface for sending events
*/
#define LOG_DIR "/data/misc/audit"
#define LOG_FILE LOG_DIR "/audit.log"
#define OLD_LOG_FILE LOG_DIR "/audit.old"
#define MAX_LOG_FILE_SIZE (1024 * 100)
static volatile int quit = 0;
static void signal_handler(int sig) {
switch (sig) {
case SIGINT:
quit = 1;
break;
}
return;
}
static void usage(char *cmd) {
printf("%s - log audit events from the kernel\n"
"OPTIONS\n"
"-k - search dmesg on startup for audit events\n"
"\n",
cmd);
}
#define RAISE(ary, c) ary[CAP_TO_INDEX(c)].permitted |= CAP_TO_MASK(c);
static void drop_privileges_or_die(void) {
struct __user_cap_header_struct capheader;
struct __user_cap_data_struct capdata[2];
if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
ERROR("Failed on prctl KEEPCAPS: %s\n", strerror(errno));
exit(1);
}
if (setgid(AID_AUDIT) < 0) {
ERROR("Failed on setgid: %s\n", strerror(errno));
exit(1);
}
if (setuid(AID_AUDIT) < 0) {
ERROR("Failed on setuid: %s\n", strerror(errno));
exit(1);
}
memset(&capheader, 0, sizeof(capheader));
memset(&capdata, 0, sizeof(capdata));
capheader.version = _LINUX_CAPABILITY_VERSION_3;
capheader.pid = 0;
RAISE(capdata, CAP_AUDIT_CONTROL);
RAISE(capdata, CAP_SYSLOG);
capdata[0].effective = capdata[0].permitted;
capdata[1].effective = capdata[1].permitted;
capdata[0].inheritable = 0;
capdata[1].inheritable = 0;
if (capset(&capheader, &capdata[0]) < 0) {
ERROR("Failed on capset: %s\n", strerror(errno));
exit(1);
}
}
int main(int argc, char *argv[]) {
int c;
struct audit_reply rep;
struct sigaction action;
int rc;
int audit_fd = -1;
int check_kernel_log = 0;
audit_log *l = NULL;
ssize_t total_bytes = 0;
struct pollfd pfds;
INFO("auditd: starting up\n");
drop_privileges_or_die();
/* register the signal handler */
action.sa_handler = signal_handler;
sigemptyset (&action.sa_mask);
action.sa_flags = 0;
rc = sigaction (SIGINT, &action, NULL);
if (rc < 0) {
rc = errno;
ERROR("Failed on set signal handler: %s\n", strerror(errno));
goto err;
}
while((c = getopt(argc, argv, "k")) != -1) {
switch(c) {
case 'k':
check_kernel_log = 1;
break;
default:
usage(argv[0]);
goto err;
}
}
/* Open the netlink socket for audit events */
audit_fd = audit_open();
if (audit_fd < 0) {
rc = errno;
ERROR("Failed on audit_set_pid with error: %s\n", strerror(errno));
goto err;
}
l = audit_log_open(LOG_FILE, OLD_LOG_FILE, MAX_LOG_FILE_SIZE);
if(!l) {
ERROR("Failed on audit_log_open\n");
goto err;
}
if (audit_set_pid(audit_fd, getpid(), WAIT_YES) < 0) {
rc = errno;
ERROR("Failed on audit_set_pid with error: %s\n", strerror(errno));
goto err;
}
pfds.fd = audit_fd;
pfds.events = POLLIN;
if(check_kernel_log) {
audit_log_put_kmsg(l);
}
while (!quit) {
/* Start reading for events */
rc = poll(&pfds, 1, -1);
if (rc == 0) {
continue;
}
else if(rc < 0) {
if (errno != EINTR) {
ERROR("Failed to poll audit log socket: %d : %s\n", errno, strerror(errno));
}
continue;
}
if (audit_get_reply(audit_fd, &rep, GET_REPLY_BLOCKING, 0) < 0) {
ERROR("Failed on audit_get_reply with error: %s\n", strerror(errno));
continue;
}
audit_log_write(l, &rep);
/* Keep reading for events */
}
err:
INFO("auditd: exiting\n");
if (audit_fd >= 0) {
audit_set_pid(audit_fd, 0, WAIT_NO);
audit_close(audit_fd);
}
audit_log_close(l);
return rc;
}
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