freebsd-nq/sys/security/audit/audit_trigger.c
Robert Watson 8805ca53e7 Rather than copying out the full audit trigger record, which includes
a queue entry field, just copy out the unsigned int that is the trigger
message.  In practice, auditd always requested sizeof(unsigned int), so
the extra bytes were ignored, but copying them out was not the intent.

MFC after:	1 month
2008-03-02 21:34:17 +00:00

178 lines
4.7 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
#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);