/*-
* Copyright (c) 2004-2009 Apple Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <config/config.h>
#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <bsm/audit.h>
#include <bsm/audit_uevents.h>
#include <bsm/auditd_lib.h>
#include <bsm/libbsm.h>
#include <asl.h>
#include <launch.h>
#include <notify.h>
#include <mach/port.h>
#include <mach/mach_error.h>
#include <mach/mach_traps.h>
#include <mach/mach.h>
#include <mach/host_special_ports.h>
#include "auditd.h"
#include "auditd_controlServer.h"
#include "audit_triggersServer.h"
/*
* Apple System Logger Handles.
*/
static aslmsg au_aslmsg = NULL;
static aslclient au_aslclient = NULL;
static mach_port_t control_port = MACH_PORT_NULL;
static mach_port_t signal_port = MACH_PORT_NULL;
static mach_port_t port_set = MACH_PORT_NULL;
/*
* Current auditing state (cache).
*/
static int auditing_state = AUD_STATE_INIT;
/*
* Maximum idle time before auditd terminates under launchd.
* If it is zero then auditd does not timeout while idle.
*/
static int max_idletime = 0;
#ifndef __BSM_INTERNAL_NOTIFY_KEY
#define __BSM_INTERNAL_NOTIFY_KEY "com.apple.audit.change"
#endif /* __BSM_INTERNAL_NOTIFY_KEY */
#ifndef __AUDIT_LAUNCHD_LABEL
#define __AUDIT_LAUNCHD_LABEL "com.apple.auditd"
#endif /* __AUDIT_LAUNCHD_LABEL */
#define MAX_MSG_SIZE 4096
/*
* Open and set up system logging.
*/
void
auditd_openlog(int debug, gid_t gid)
{
uint32_t opt = 0;
char *cp = NULL;
if (debug)
opt = ASL_OPT_STDERR;
au_aslclient = asl_open("auditd", "com.apple.auditd", opt);
au_aslmsg = asl_new(ASL_TYPE_MSG);
#ifdef ASL_KEY_READ_UID
/*
* Make it only so the audit administrator and members of the audit
* review group (if used) have access to the auditd system log messages.
*/
asl_set(au_aslmsg, ASL_KEY_READ_UID, "0");
asprintf(&cp, "%u", gid);
if (cp != NULL) {
#ifdef ASL_KEY_READ_GID
asl_set(au_aslmsg, ASL_KEY_READ_GID, cp);
#endif
free(cp);
}
#endif
/*
* Set the client-side system log filtering.
*/
if (debug)
asl_set_filter(au_aslclient,
ASL_FILTER_MASK_UPTO(ASL_LEVEL_DEBUG));
else
asl_set_filter(au_aslclient,
ASL_FILTER_MASK_UPTO(ASL_LEVEL_INFO));
}
/*
* Log messages at different priority levels.
*/
void
auditd_log_err(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
asl_vlog(au_aslclient, au_aslmsg, ASL_LEVEL_ERR, fmt, ap);
va_end(ap);
}
void
auditd_log_notice(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
asl_vlog(au_aslclient, au_aslmsg, ASL_LEVEL_NOTICE, fmt, ap);
va_end(ap);
}
void
auditd_log_info(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
asl_vlog(au_aslclient, au_aslmsg, ASL_LEVEL_INFO, fmt, ap);
va_end(ap);
}
void
auditd_log_debug(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
asl_vlog(au_aslclient, au_aslmsg, ASL_LEVEL_DEBUG, fmt, ap);
va_end(ap);
}
/*
* Get the auditing state from the kernel and cache it.
*/
static void
init_audit_state(void)
{
int au_cond;
if (audit_get_cond(&au_cond) < 0) {
if (errno != ENOSYS) {
auditd_log_err("Audit status check failed (%s)",
strerror(errno));
}
auditing_state = AUD_STATE_DISABLED;
} else
if (au_cond == AUC_NOAUDIT || au_cond == AUC_DISABLED)
auditing_state = AUD_STATE_DISABLED;
else
auditing_state = AUD_STATE_ENABLED;
}
/*
* Update the cached auditing state. Let other tasks that may be caching it
* as well to update their state via notify(3).
*/
void
auditd_set_state(int state)
{
int old_auditing_state = auditing_state;
if (state == AUD_STATE_INIT)
init_audit_state();
else
auditing_state = state;
if (auditing_state != old_auditing_state) {
notify_post(__BSM_INTERNAL_NOTIFY_KEY);
if (auditing_state == AUD_STATE_ENABLED)
auditd_log_notice("Auditing enabled");
if (auditing_state == AUD_STATE_DISABLED)
auditd_log_notice("Auditing disabled");
}
}
/*
* Get the cached auditing state.
*/
int
auditd_get_state(void)
{
if (auditing_state == AUD_STATE_INIT) {
init_audit_state();
notify_post(__BSM_INTERNAL_NOTIFY_KEY);
}
return (auditing_state);
}
/*
* Lookup the audit mach port in the launchd dictionary.
*/
static mach_port_t
lookup_machport(const char *label)
{
launch_data_t msg, msd, ld, cdict, to;
mach_port_t mp = MACH_PORT_NULL;
msg = launch_data_new_string(LAUNCH_KEY_CHECKIN);
cdict = launch_msg(msg);
if (cdict == NULL) {
auditd_log_err("launch_msg(\"" LAUNCH_KEY_CHECKIN
"\") IPC failure: %m");
return (MACH_PORT_NULL);
}
if (launch_data_get_type(cdict) == LAUNCH_DATA_ERRNO) {
errno = launch_data_get_errno(cdict);
auditd_log_err("launch_data_get_type() can't get dict: %m");
return (MACH_PORT_NULL);
}
to = launch_data_dict_lookup(cdict, LAUNCH_JOBKEY_TIMEOUT);
if (to) {
max_idletime = launch_data_get_integer(to);
auditd_log_debug("launchd timeout set to %d", max_idletime);
} else {
auditd_log_debug("launchd timeout not set, setting to 60");
max_idletime = 60;
}
msd = launch_data_dict_lookup(cdict, LAUNCH_JOBKEY_MACHSERVICES);
if (msd == NULL) {
auditd_log_err(
"launch_data_dict_lookup() can't get mach services");
return (MACH_PORT_NULL);
}
ld = launch_data_dict_lookup(msd, label);
if (ld == NULL) {
auditd_log_err("launch_data_dict_lookup can't find %s", label);
return (MACH_PORT_NULL);
}
mp = launch_data_get_machport(ld);
return (mp);
}
static int
mach_setup(int launchd_flag)
{
mach_msg_type_name_t poly;
/*
* Allocate a port set.
*/
if (mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_PORT_SET,
&port_set) != KERN_SUCCESS) {
auditd_log_err("Allocation of port set failed");
return (-1);
}
/*
* Allocate a signal reflection port.
*/
if (mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE,
&signal_port) != KERN_SUCCESS ||
mach_port_move_member(mach_task_self(), signal_port, port_set) !=
KERN_SUCCESS) {
auditd_log_err("Allocation of signal port failed");
return (-1);
}
/*
* Allocate a trigger port.
*/
if (launchd_flag) {
/*
* If started under launchd, lookup port in launchd dictionary.
*/
if ((control_port = lookup_machport(__AUDIT_LAUNCHD_LABEL)) ==
MACH_PORT_NULL || mach_port_move_member(mach_task_self(),
control_port, port_set) != KERN_SUCCESS) {
auditd_log_err("Cannot get Mach control port"
" via launchd");
return (-1);
} else
auditd_log_debug("Mach control port registered"
" via launchd");
} else {
/*
* If not started under launchd, allocate port and register.
*/
if (mach_port_allocate(mach_task_self(),
MACH_PORT_RIGHT_RECEIVE, &control_port) != KERN_SUCCESS ||
mach_port_move_member(mach_task_self(), control_port,
port_set) != KERN_SUCCESS)
auditd_log_err("Allocation of trigger port failed");
/*
* Create a send right on our trigger port.
*/
mach_port_extract_right(mach_task_self(), control_port,
MACH_MSG_TYPE_MAKE_SEND, &control_port, &poly);
/*
* Register the trigger port with the kernel.
*/
if (host_set_audit_control_port(mach_host_self(),
control_port) != KERN_SUCCESS) {
auditd_log_err("Cannot set Mach control port");
return (-1);
} else
auditd_log_debug("Mach control port registered");
}
return (0);
}
/*
* Open the trigger messaging mechanism.
*/
int
auditd_open_trigger(int launchd_flag)
{
return (mach_setup(launchd_flag));
}
/*
* Close the trigger messaging mechanism.
*/
int
auditd_close_trigger(void)
{
return (0);
}
/*
* Combined server handler. Called by the mach message loop when there is
* a trigger or signal message.
*/
static boolean_t
auditd_combined_server(mach_msg_header_t *InHeadP, mach_msg_header_t *OutHeadP)
{
mach_port_t local_port = InHeadP->msgh_local_port;
/* Reset the idle time alarm, if used. */
if (max_idletime)
alarm(max_idletime);
if (local_port == signal_port) {
int signo = InHeadP->msgh_id;
switch(signo) {
case SIGTERM:
case SIGALRM:
auditd_terminate();
/* Not reached. */
case SIGCHLD:
auditd_reap_children();
return (TRUE);
case SIGHUP:
auditd_config_controls();
return (TRUE);
default:
auditd_log_info("Received signal %d", signo);
return (TRUE);
}
} else if (local_port == control_port) {
boolean_t result;
result = audit_triggers_server(InHeadP, OutHeadP);
if (!result)
result = auditd_control_server(InHeadP, OutHeadP);
return (result);
}
auditd_log_info("Recevied msg on bad port 0x%x.", local_port);
return (FALSE);
}
/*
* The main event loop. Wait for trigger messages or signals and handle them.
* It should not return unless there is a problem.
*/
void
auditd_wait_for_events(void)
{
kern_return_t result;
/*
* Call the mach messaging server loop.
*/
result = mach_msg_server(auditd_combined_server, MAX_MSG_SIZE,
port_set, MACH_MSG_OPTION_NONE);
}
/*
* Implementation of the audit_triggers() MIG simpleroutine. Simply a
* wrapper function. This handles input from the kernel on the host
* special mach port.
*/
kern_return_t
audit_triggers(mach_port_t __unused audit_port, int trigger)
{
auditd_handle_trigger(trigger);
return (KERN_SUCCESS);
}
/*
* Implementation of the auditd_control() MIG simpleroutine. Simply a
* wrapper function. This handles input from the audit(1) tool.
*/
kern_return_t
auditd_control(mach_port_t __unused auditd_port, int trigger)
{
auditd_handle_trigger(trigger);
return (KERN_SUCCESS);
}
/*
* When we get a signal, we are often not at a clean point. So, little can
* be done in the signal handler itself. Instead, we send a message to the
* main servicing loop to do proper handling from a non-signal-handler
* context.
*/
void
auditd_relay_signal(int signal)
{
mach_msg_empty_send_t msg;
msg.header.msgh_id = signal;
msg.header.msgh_remote_port = signal_port;
msg.header.msgh_local_port = MACH_PORT_NULL;
msg.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0);
mach_msg(&(msg.header), MACH_SEND_MSG|MACH_SEND_TIMEOUT, sizeof(msg),
0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
}