5ec681997d
Change send_trigger() prototype to return an int, so that user space callers can tell if the message was successfully placed in the trigger queue. This isn't quite the same as it being successfully received, but is close enough that we can generate a more useful warning message in audit(8). Obtained from: TrustedBSD Project
174 lines
4.5 KiB
C
174 lines
4.5 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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* $FreeBSD$
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*/
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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.
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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, sizeof *ti, 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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send_trigger(unsigned int trigger)
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{
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struct trigger_info *ti;
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/* If nobody's listening, we ain't talking. */
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if (!audit_isopen)
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return (ENODEV);
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/*
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* XXXAUDIT: Use a condition variable instead of msleep/wakeup?
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*/
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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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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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