xref: /illumos-gate/usr/src/lib/libbsm/common/audit_plugin.c (revision 27954b0d964ffcb749cf19296906e7fecdf3da1b)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * private interfaces for auditd plugins and auditd.
26  */
27 
28 #include <bsm/audit.h>
29 #include <bsm/audit_record.h>
30 #include <bsm/audit_uevents.h>
31 #include <bsm/libbsm.h>
32 #include <errno.h>
33 #include <fcntl.h>
34 #include <libintl.h>
35 #include <pthread.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <sys/file.h>
40 #include <sys/stat.h>
41 #include <sys/types.h>
42 #include <syslog.h>
43 #include <unistd.h>
44 #include <wait.h>
45 #include "audit_plugin.h"
46 
47 static char	auditwarn[] = "/etc/security/audit_warn";
48 static pthread_mutex_t	syslog_lock;
49 
50 static void
51 init_syslog_mutex()
52 {
53 	(void) pthread_mutex_init(&syslog_lock, NULL);
54 }
55 
56 /*
57  * audit_syslog() -- generate syslog messages from threads that use
58  * different severity, facility code, and application names.
59  *
60  * syslog(3C) is thread safe, but the set openlog() / syslog() /
61  * closelog() is not.
62  *
63  * Assumption:  the app_name and facility code are paired, i.e.,
64  * if the facility code for this call is the same as for the
65  * the previous, the app_name hasn't changed.
66  */
67 void
68 __audit_syslog(const char *app_name, int flags, int facility, int severity,
69     const char *message)
70 {
71 	static pthread_once_t	once_control = PTHREAD_ONCE_INIT;
72 	static int		logopen = 0;
73 	static int		prev_facility = -1;
74 
75 	(void) pthread_once(&once_control, init_syslog_mutex);
76 
77 	(void) pthread_mutex_lock(&syslog_lock);
78 	if (prev_facility != facility) {
79 		if (logopen)
80 			closelog();
81 		openlog(app_name, flags, facility);
82 		syslog(severity, "%s", message);
83 		(void) pthread_mutex_unlock(&syslog_lock);
84 	} else {
85 		syslog(severity, "%s", message);
86 		(void) pthread_mutex_unlock(&syslog_lock);
87 	}
88 }
89 
90 /*
91  * __audit_dowarn - invoke the shell script auditwarn to notify the
92  *	adminstrator about a given problem.
93  * parameters -
94  *	option - what the problem is
95  *	text - when used with options soft and hard: which file was being
96  *		   used when the filesystem filled up
97  *	       when used with the plugin option:  error detail
98  *	count - used with various options: how many times auditwarn has
99  *		been called for this problem since it was last cleared.
100  */
101 void
102 __audit_dowarn(char *option, char *text, int count)
103 {
104 	pid_t		pid;
105 	int		st;
106 	char		countstr[5];
107 	char		warnstring[80];
108 	char		empty[1] = "";
109 
110 	if ((pid = fork1()) == -1) {
111 		__audit_syslog("auditd", LOG_PID | LOG_ODELAY | LOG_CONS,
112 		    LOG_DAEMON, LOG_ALERT, gettext("audit_warn fork failed\n"));
113 		return;
114 	}
115 	if (pid != 0) {
116 		(void) waitpid(pid, &st, 0);
117 		return;
118 	}
119 	(void) sprintf(countstr, "%d", count);
120 	if (text == NULL)
121 		text = empty;
122 
123 	if (strcmp(option, "soft") == 0 || strcmp(option, "hard") == 0)
124 		(void) execl(auditwarn, auditwarn, option, text, 0);
125 
126 	else if (strcmp(option, "allhard") == 0 ||
127 	    strcmp(option, "getacdir") == 0)
128 		(void) execl(auditwarn, auditwarn, option, countstr, 0);
129 	else if (strcmp(option, "plugin") == 0)
130 		(void) execl(auditwarn, auditwarn, option, text, countstr, 0);
131 	else
132 		(void) execl(auditwarn, auditwarn, option, 0);
133 	/*
134 	 * (execl failed)
135 	 */
136 	if (strcmp(option, "soft") == 0)
137 		(void) sprintf(warnstring,
138 		    gettext("soft limit in %s.\n"), text);
139 	else if (strcmp(option, "hard") == 0)
140 		(void) sprintf(warnstring,
141 		    gettext("hard limit in %s.\n"), text);
142 	else if (strcmp(option, "allhard") == 0)
143 		(void) sprintf(warnstring,
144 		    gettext("All audit filesystems are full.\n"));
145 	else if (strcmp(option, "getacmin") == 0)
146 		(void) sprintf(warnstring,
147 		    gettext("audit_control minfree error.\n"));
148 	else if (strcmp(option, "getacdir") == 0)
149 		(void) sprintf(warnstring,
150 		    gettext("audit_control directory error.\n"));
151 	else
152 		(void) sprintf(warnstring,
153 		    gettext("error %s.\n"), option);
154 
155 	__audit_syslog("auditd", LOG_PID | LOG_ODELAY | LOG_CONS, LOG_AUTH,
156 	    LOG_ALERT, (const char *)warnstring);
157 
158 	exit(1);
159 }
160 
161 /*
162  * __audit_dowarn2 - invoke the shell script auditwarn to notify the
163  *	adminstrator about a given problem.
164  * parameters -
165  *	option - what the problem is
166  *	name - entity reporting the problem (ie, plugin name)
167  *	error - error string
168  *	text - when used with options soft and hard: which file was being
169  *		   used when the filesystem filled up
170  *	       when used with the plugin option:  error detail
171  *	count - used with various options: how many times auditwarn has
172  *		been called for this problem since it was last cleared.
173  */
174 void
175 __audit_dowarn2(char *option, char *name, char *error, char *text, int count)
176 {
177 	pid_t		pid;
178 	int		st;
179 	char		countstr[5];
180 	char		warnstring[80];
181 	char		empty[4] = "...";
182 	char		none[3] = "--";
183 
184 	if ((pid = fork()) == -1) {
185 		__audit_syslog("auditd", LOG_PID | LOG_ODELAY | LOG_CONS,
186 		    LOG_DAEMON, LOG_ALERT, gettext("audit_warn fork failed\n"));
187 		return;
188 	}
189 	if (pid != 0) {
190 		(void) waitpid(pid, &st, 0);
191 		return;
192 	}
193 	(void) sprintf(countstr, "%d", count);
194 	if ((text == NULL) || (*text == '\0'))
195 		text = empty;
196 	if ((name == NULL) || (*name == '\0'))
197 		name = none;
198 
199 	(void) execl(auditwarn, auditwarn, option, name, error, text,
200 	    countstr, 0);
201 
202 	/*
203 	 * (execl failed)
204 	 */
205 	(void) sprintf(warnstring,
206 	    gettext("audit_control plugin error: %s\n"), text);
207 
208 	__audit_syslog("auditd", LOG_PID | LOG_ODELAY | LOG_CONS, LOG_AUTH,
209 	    LOG_ALERT, (const char *)warnstring);
210 
211 	exit(1);
212 }
213 
214 /*
215  * logpost - post the new audit log file name.
216  *
217  *	Entry	name = active audit.log file name
218  *			NULL, if checking writability (auditd),
219  *			changing audit log files, error, or exiting (binfile).
220  *
221  *	Exit	0 = success
222  *		1 = system error -- errno
223  *		    audit_warn called with the specific error
224  *
225  */
226 int
227 __logpost(char *name)
228 {
229 	int lerrno;
230 
231 	if (unlink(BINFILE_FILE) != 0 &&
232 	    errno != ENOENT) {
233 
234 		lerrno = errno;
235 		__audit_dowarn("tmpfile", strerror(errno), 0);
236 		errno = lerrno;
237 		return (1);
238 	}
239 	if (name == NULL || *name == '\0') {
240 		/* audit_binfile not active, no file pointer */
241 		return (0);
242 	}
243 	if (symlink(name, BINFILE_FILE) != 0) {
244 
245 		lerrno = errno;
246 		__audit_dowarn("tmpfile", strerror(errno), 0);
247 		errno = lerrno;
248 		return (1);
249 	}
250 
251 	return (0);
252 }
253 
254 /*
255  * debug use - open a file for auditd and its plugins for debug
256  */
257 FILE *
258 __auditd_debug_file_open() {
259 	static FILE	*fp = NULL;
260 
261 	if (fp != NULL)
262 		return (fp);
263 	if ((fp = fopen("/var/audit/dump", "aF")) == NULL)
264 		(void) fprintf(stderr, "failed to open debug file:  %s\n",
265 		    strerror(errno));
266 
267 	return (fp);
268 }
269