2 * Copyright (c) 2005 Wayne J. Salamon
5 * This software was developed by Wayne Salamon for the TrustedBSD Project.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/malloc.h>
36 #include <sys/queue.h>
37 #include <sys/systm.h>
40 #include <security/audit/audit.h>
41 #include <security/audit/audit_private.h>
44 * Structures and operations to support the basic character special device
45 * used to communicate with userland. /dev/audit reliably delivers one-byte
46 * messages to a listening application (or discards them if there is no
47 * listening application).
49 * Currently, select/poll are not supported on the trigger device.
53 TAILQ_ENTRY(trigger_info) list;
56 static MALLOC_DEFINE(M_AUDITTRIGGER, "audit_trigger", "Audit trigger events");
57 static struct cdev *audit_dev;
58 static int audit_isopen = 0;
59 static TAILQ_HEAD(, trigger_info) trigger_list;
60 static struct mtx audit_trigger_mtx;
63 audit_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
67 /* Only one process may open the device at a time. */
68 mtx_lock(&audit_trigger_mtx);
74 mtx_unlock(&audit_trigger_mtx);
80 audit_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
82 struct trigger_info *ti;
84 /* Flush the queue of pending trigger events. */
85 mtx_lock(&audit_trigger_mtx);
87 while (!TAILQ_EMPTY(&trigger_list)) {
88 ti = TAILQ_FIRST(&trigger_list);
89 TAILQ_REMOVE(&trigger_list, ti, list);
90 free(ti, M_AUDITTRIGGER);
92 mtx_unlock(&audit_trigger_mtx);
98 audit_read(struct cdev *dev, struct uio *uio, int ioflag)
101 struct trigger_info *ti = NULL;
103 mtx_lock(&audit_trigger_mtx);
104 while (TAILQ_EMPTY(&trigger_list)) {
105 error = msleep(&trigger_list, &audit_trigger_mtx,
106 PSOCK | PCATCH, "auditd", 0);
111 ti = TAILQ_FIRST(&trigger_list);
112 TAILQ_REMOVE(&trigger_list, ti, list);
114 mtx_unlock(&audit_trigger_mtx);
116 error = uiomove(ti, sizeof *ti, uio);
117 free(ti, M_AUDITTRIGGER);
123 audit_write(struct cdev *dev, struct uio *uio, int ioflag)
126 /* Communication is kernel->userspace only. */
131 send_trigger(unsigned int trigger)
133 struct trigger_info *ti;
135 /* If nobody's listening, we ain't talking. */
140 * Note: Use a condition variable instead of msleep/wakeup?
142 ti = malloc(sizeof *ti, M_AUDITTRIGGER, M_WAITOK);
143 mtx_lock(&audit_trigger_mtx);
144 ti->trigger = trigger;
145 TAILQ_INSERT_TAIL(&trigger_list, ti, list);
146 wakeup(&trigger_list);
147 mtx_unlock(&audit_trigger_mtx);
151 static struct cdevsw audit_cdevsw = {
152 .d_version = D_VERSION,
153 .d_open = audit_open,
154 .d_close = audit_close,
155 .d_read = audit_read,
156 .d_write = audit_write,
161 audit_trigger_init(void)
164 TAILQ_INIT(&trigger_list);
165 mtx_init(&audit_trigger_mtx, "audit_trigger_mtx", NULL, MTX_DEF);
169 audit_trigger_cdev_init(void *unused)
172 /* Create the special device file. */
173 audit_dev = make_dev(&audit_cdevsw, 0, UID_ROOT, GID_KMEM, 0600,
177 SYSINIT(audit_trigger_cdev_init, SI_SUB_DRIVERS, SI_ORDER_MIDDLE,
178 audit_trigger_cdev_init, NULL);