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/*-
* Copyright (c) 2005 Wayne J. Salamon
* All rights reserved.
*
* This software was developed by Wayne Salamon for the TrustedBSD Project.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND 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 THE AUTHOR OR 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <security/audit/audit.h>
#include <security/audit/audit_private.h>
/*
* Structures and operations to support the basic character special device
* used to communicate with userland. /dev/audit reliably delivers one-byte
* messages to a listening application (or discards them if there is no
* listening application).
*
* Currently, select/poll are not supported on the trigger device.
*/
struct trigger_info {
unsigned int trigger;
TAILQ_ENTRY(trigger_info) list;
};
static MALLOC_DEFINE(M_AUDITTRIGGER, "audit_trigger", "Audit trigger events");
static struct cdev *audit_dev;
static int audit_isopen = 0;
static TAILQ_HEAD(, trigger_info) trigger_list;
static struct mtx audit_trigger_mtx;
static int
audit_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
int error;
/* Only one process may open the device at a time. */
mtx_lock(&audit_trigger_mtx);
if (!audit_isopen) {
error = 0;
audit_isopen = 1;
} else
error = EBUSY;
mtx_unlock(&audit_trigger_mtx);
return (error);
}
static int
audit_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct trigger_info *ti;
/* Flush the queue of pending trigger events. */
mtx_lock(&audit_trigger_mtx);
audit_isopen = 0;
while (!TAILQ_EMPTY(&trigger_list)) {
ti = TAILQ_FIRST(&trigger_list);
TAILQ_REMOVE(&trigger_list, ti, list);
free(ti, M_AUDITTRIGGER);
}
mtx_unlock(&audit_trigger_mtx);
return (0);
}
static int
audit_read(struct cdev *dev, struct uio *uio, int ioflag)
{
int error = 0;
struct trigger_info *ti = NULL;
mtx_lock(&audit_trigger_mtx);
while (TAILQ_EMPTY(&trigger_list)) {
error = msleep(&trigger_list, &audit_trigger_mtx,
PSOCK | PCATCH, "auditd", 0);
if (error)
break;
}
if (!error) {
ti = TAILQ_FIRST(&trigger_list);
TAILQ_REMOVE(&trigger_list, ti, list);
}
mtx_unlock(&audit_trigger_mtx);
if (!error) {
error = uiomove(&ti->trigger, sizeof(ti->trigger), uio);
free(ti, M_AUDITTRIGGER);
}
return (error);
}
static int
audit_write(struct cdev *dev, struct uio *uio, int ioflag)
{
/* Communication is kernel->userspace only. */
return (EOPNOTSUPP);
}
int
audit_send_trigger(unsigned int trigger)
{
struct trigger_info *ti;
ti = malloc(sizeof *ti, M_AUDITTRIGGER, M_WAITOK);
mtx_lock(&audit_trigger_mtx);
if (!audit_isopen) {
/* If nobody's listening, we ain't talking. */
mtx_unlock(&audit_trigger_mtx);
free(ti, M_AUDITTRIGGER);
return (ENODEV);
}
ti->trigger = trigger;
TAILQ_INSERT_TAIL(&trigger_list, ti, list);
wakeup(&trigger_list);
mtx_unlock(&audit_trigger_mtx);
return (0);
}
static struct cdevsw audit_cdevsw = {
.d_version = D_VERSION,
.d_open = audit_open,
.d_close = audit_close,
.d_read = audit_read,
.d_write = audit_write,
.d_name = "audit"
};
void
audit_trigger_init(void)
{
TAILQ_INIT(&trigger_list);
mtx_init(&audit_trigger_mtx, "audit_trigger_mtx", NULL, MTX_DEF);
}
static void
audit_trigger_cdev_init(void *unused)
{
/* Create the special device file. */
audit_dev = make_dev(&audit_cdevsw, 0, UID_ROOT, GID_KMEM, 0600,
AUDITDEV_FILENAME);
}
SYSINIT(audit_trigger_cdev_init, SI_SUB_DRIVERS, SI_ORDER_MIDDLE,
audit_trigger_cdev_init, NULL);
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