179 lines
4.8 KiB
C
179 lines
4.8 KiB
C
/*-
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* Copyright (c) 2005 Wayne J. Salamon
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* All rights reserved.
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*
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* This software was developed by Wayne Salamon for the TrustedBSD Project.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/queue.h>
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#include <sys/systm.h>
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#include <sys/uio.h>
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#include <security/audit/audit.h>
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#include <security/audit/audit_private.h>
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/*
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* Structures and operations to support the basic character special device
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* used to communicate with userland. /dev/audit reliably delivers one-byte
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* messages to a listening application (or discards them if there is no
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* listening application).
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*
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* Currently, select/poll are not supported on the trigger device.
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*/
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struct trigger_info {
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unsigned int trigger;
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TAILQ_ENTRY(trigger_info) list;
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};
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static MALLOC_DEFINE(M_AUDITTRIGGER, "audit_trigger", "Audit trigger events");
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static struct cdev *audit_dev;
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static int audit_isopen = 0;
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static TAILQ_HEAD(, trigger_info) trigger_list;
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static struct mtx audit_trigger_mtx;
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static int
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audit_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
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{
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int error;
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/* Only one process may open the device at a time. */
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mtx_lock(&audit_trigger_mtx);
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if (!audit_isopen) {
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error = 0;
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audit_isopen = 1;
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} else
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error = EBUSY;
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mtx_unlock(&audit_trigger_mtx);
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return (error);
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}
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static int
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audit_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
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{
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struct trigger_info *ti;
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/* Flush the queue of pending trigger events. */
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mtx_lock(&audit_trigger_mtx);
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audit_isopen = 0;
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while (!TAILQ_EMPTY(&trigger_list)) {
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ti = TAILQ_FIRST(&trigger_list);
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TAILQ_REMOVE(&trigger_list, ti, list);
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free(ti, M_AUDITTRIGGER);
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}
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mtx_unlock(&audit_trigger_mtx);
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return (0);
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}
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static int
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audit_read(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int error = 0;
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struct trigger_info *ti = NULL;
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mtx_lock(&audit_trigger_mtx);
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while (TAILQ_EMPTY(&trigger_list)) {
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error = msleep(&trigger_list, &audit_trigger_mtx,
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PSOCK | PCATCH, "auditd", 0);
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if (error)
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break;
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}
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if (!error) {
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ti = TAILQ_FIRST(&trigger_list);
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TAILQ_REMOVE(&trigger_list, ti, list);
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}
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mtx_unlock(&audit_trigger_mtx);
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if (!error) {
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error = uiomove(&ti->trigger, sizeof(ti->trigger), uio);
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free(ti, M_AUDITTRIGGER);
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}
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return (error);
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}
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static int
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audit_write(struct cdev *dev, struct uio *uio, int ioflag)
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{
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/* Communication is kernel->userspace only. */
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return (EOPNOTSUPP);
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}
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int
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audit_send_trigger(unsigned int trigger)
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{
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struct trigger_info *ti;
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ti = malloc(sizeof *ti, M_AUDITTRIGGER, M_WAITOK);
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mtx_lock(&audit_trigger_mtx);
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if (!audit_isopen) {
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/* If nobody's listening, we ain't talking. */
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mtx_unlock(&audit_trigger_mtx);
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free(ti, M_AUDITTRIGGER);
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return (ENODEV);
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}
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ti->trigger = trigger;
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TAILQ_INSERT_TAIL(&trigger_list, ti, list);
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wakeup(&trigger_list);
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mtx_unlock(&audit_trigger_mtx);
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return (0);
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}
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static struct cdevsw audit_cdevsw = {
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.d_version = D_VERSION,
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.d_open = audit_open,
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.d_close = audit_close,
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.d_read = audit_read,
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.d_write = audit_write,
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.d_name = "audit"
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};
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void
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audit_trigger_init(void)
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{
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TAILQ_INIT(&trigger_list);
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mtx_init(&audit_trigger_mtx, "audit_trigger_mtx", NULL, MTX_DEF);
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}
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static void
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audit_trigger_cdev_init(void *unused)
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{
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/* Create the special device file. */
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audit_dev = make_dev(&audit_cdevsw, 0, UID_ROOT, GID_KMEM, 0600,
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AUDITDEV_FILENAME);
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}
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SYSINIT(audit_trigger_cdev_init, SI_SUB_DRIVERS, SI_ORDER_MIDDLE,
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audit_trigger_cdev_init, NULL);
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