xref: /freebsd/contrib/openbsm/libbsm/bsm_notify.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * Copyright (c) 2004-2009 Apple Inc.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1.  Redistributions of source code must retain the above copyright
9  *     notice, this list of conditions and the following disclaimer.
10  * 2.  Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
14  *     its contributors may be used to endorse or promote products derived
15  *     from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
26  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 /*
31  * Based on sample code from Marc Majka.
32  */
33 #include <sys/types.h>
34 
35 #include <config/config.h>
36 #ifdef HAVE_FULL_QUEUE_H
37 #include <sys/queue.h>
38 #else /* !HAVE_FULL_QUEUE_H */
39 #include <compat/queue.h>
40 #endif /* !HAVE_FULL_QUEUE_H */
41 
42 #include <bsm/audit_internal.h>
43 #include <bsm/libbsm.h>
44 
45 #include <errno.h>
46 #include <inttypes.h>
47 #include <stdarg.h>
48 #include <string.h>
49 #include <syslog.h>
50 
51 
52 #ifdef __APPLE__
53 #include <notify.h>
54 /* If 1, assumes a kernel that sends the right notification. */
55 #define	AUDIT_NOTIFICATION_ENABLED	1
56 
57 #if AUDIT_NOTIFICATION_ENABLED
58 static int	token = 0;
59 #endif	/* AUDIT_NOTIFICATION_ENABLED */
60 
61 static int	au_cond = AUC_UNSET;	/* <bsm/audit.h> */
62 
63 uint32_t
64 au_notify_initialize(void)
65 {
66 #if AUDIT_NOTIFICATION_ENABLED
67 	uint32_t status;
68 	int ignore_first;
69 
70 	status = notify_register_check(__BSM_INTERNAL_NOTIFY_KEY, &token);
71 	if (status != NOTIFY_STATUS_OK)
72 		return (status);
73 	status = notify_check(token, &ignore_first);
74 	if (status != NOTIFY_STATUS_OK)
75 		return (status);
76 #endif
77 
78 	if (audit_get_cond(&au_cond) != 0) {
79 		syslog(LOG_ERR, "Initial audit status check failed (%s)",
80 		    strerror(errno));
81 		if (errno == ENOSYS)	/* auditon() unimplemented. */
82 			return (AU_UNIMPL);
83 		return (NOTIFY_STATUS_FAILED);	/* Is there a better code? */
84 	}
85 	return (NOTIFY_STATUS_OK);
86 }
87 
88 int
89 au_notify_terminate(void)
90 {
91 
92 #if AUDIT_NOTIFICATION_ENABLED
93 	return ((notify_cancel(token) == NOTIFY_STATUS_OK) ? 0 : -1);
94 #else
95 	return (0);
96 #endif
97 }
98 
99 /*
100  * On error of any notify(3) call, reset 'au_cond' to ensure we re-run
101  * au_notify_initialize() next time 'round--but assume auditing is on.  This
102  * is a slight performance hit if auditing is off, but at least the system
103  * will behave correctly.  The notification calls are unlikely to fail,
104  * anyway.
105  */
106 int
107 au_get_state(void)
108 {
109 #if AUDIT_NOTIFICATION_ENABLED
110 	int did_notify;
111 #endif
112 	int status;
113 
114 	/*
115 	 * Don't make the client initialize this set of routines, but take the
116 	 * slight performance hit by checking ourselves every time.
117 	 */
118 	if (au_cond == AUC_UNSET) {
119 		status = au_notify_initialize();
120 		if (status != NOTIFY_STATUS_OK) {
121 			if (status == AU_UNIMPL)
122 				return (AU_UNIMPL);
123 			return (AUC_AUDITING);
124 		} else
125 			return (au_cond);
126 	}
127 #if AUDIT_NOTIFICATION_ENABLED
128 	status = notify_check(token, &did_notify);
129 	if (status != NOTIFY_STATUS_OK) {
130 		au_cond = AUC_UNSET;
131 		return (AUC_AUDITING);
132 	}
133 
134 	if (did_notify == 0)
135 		return (au_cond);
136 #endif
137 
138 	if (audit_get_cond(&au_cond) != 0) {
139 		/* XXX Reset au_cond to AUC_UNSET? */
140 		syslog(LOG_ERR, "Audit status check failed (%s)",
141 		    strerror(errno));
142 		if (errno == ENOSYS)	/* Function unimplemented. */
143 			return (AU_UNIMPL);
144 		return (errno);
145 	}
146 
147 	switch (au_cond) {
148 	case AUC_NOAUDIT:	/* Auditing suspended. */
149 	case AUC_DISABLED:	/* Auditing shut off. */
150 		return (AUC_NOAUDIT);
151 
152 	case AUC_UNSET:		/* Uninitialized; shouldn't get here. */
153 	case AUC_AUDITING:	/* Audit on. */
154 	default:
155 		return (AUC_AUDITING);
156 	}
157 }
158 #endif	/* !__APPLE__ */
159 
160 int
161 cannot_audit(int val __unused)
162 {
163 #ifdef __APPLE__
164 	return (!(au_get_state() == AUC_AUDITING));
165 #else
166 	int cond;
167 
168 	if (audit_get_cond(&cond) != 0) {
169 		if (errno != ENOSYS) {
170 			syslog(LOG_ERR, "Audit status check failed (%s)",
171 			    strerror(errno));
172 		}
173 		return (1);
174 	}
175 	if (cond == AUC_NOAUDIT || cond == AUC_DISABLED)
176 		return (1);
177 	return (0);
178 #endif	/* !__APPLE__ */
179 }
180