xref: /freebsd/crypto/openssh/audit-bsm.c (revision bb15ca603fa442c72dde3f3cb8b46db6970e3950)
1 /* $Id: audit-bsm.c,v 1.7 2011/01/17 10:15:29 dtucker Exp $ */
2 
3 /*
4  * TODO
5  *
6  * - deal with overlap between this and sys_auth_allowed_user
7  *   sys_auth_record_login and record_failed_login.
8  */
9 
10 /*
11  * Copyright 1988-2002 Sun Microsystems, Inc.  All rights reserved.
12  * Use is subject to license terms.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  *
34  */
35 /* #pragma ident	"@(#)bsmaudit.c	1.1	01/09/17 SMI" */
36 
37 #include "includes.h"
38 #if defined(USE_BSM_AUDIT)
39 
40 #include <sys/types.h>
41 
42 #include <errno.h>
43 #include <netdb.h>
44 #include <stdarg.h>
45 #include <string.h>
46 #include <unistd.h>
47 
48 #include "ssh.h"
49 #include "log.h"
50 #include "key.h"
51 #include "hostfile.h"
52 #include "auth.h"
53 #include "xmalloc.h"
54 
55 #ifndef AUE_openssh
56 # define AUE_openssh     32800
57 #endif
58 #include <bsm/audit.h>
59 #include <bsm/libbsm.h>
60 #include <bsm/audit_uevents.h>
61 #include <bsm/audit_record.h>
62 #include <locale.h>
63 
64 #if defined(HAVE_GETAUDIT_ADDR)
65 #define	AuditInfoStruct		auditinfo_addr
66 #define AuditInfoTermID		au_tid_addr_t
67 #define SetAuditFunc(a,b)	setaudit_addr((a),(b))
68 #define SetAuditFuncText	"setaudit_addr"
69 #define AUToSubjectFunc		au_to_subject_ex
70 #define AUToReturnFunc(a,b)	au_to_return32((a), (int32_t)(b))
71 #else
72 #define	AuditInfoStruct		auditinfo
73 #define AuditInfoTermID		au_tid_t
74 #define SetAuditFunc(a,b)	setaudit(a)
75 #define SetAuditFuncText	"setaudit"
76 #define AUToSubjectFunc		au_to_subject
77 #define AUToReturnFunc(a,b)	au_to_return((a), (u_int)(b))
78 #endif
79 
80 #ifndef cannot_audit
81 extern int	cannot_audit(int);
82 #endif
83 extern void	aug_init(void);
84 extern void	aug_save_auid(au_id_t);
85 extern void	aug_save_uid(uid_t);
86 extern void	aug_save_euid(uid_t);
87 extern void	aug_save_gid(gid_t);
88 extern void	aug_save_egid(gid_t);
89 extern void	aug_save_pid(pid_t);
90 extern void	aug_save_asid(au_asid_t);
91 extern void	aug_save_tid(dev_t, unsigned int);
92 extern void	aug_save_tid_ex(dev_t, u_int32_t *, u_int32_t);
93 extern int	aug_save_me(void);
94 extern int	aug_save_namask(void);
95 extern void	aug_save_event(au_event_t);
96 extern void	aug_save_sorf(int);
97 extern void	aug_save_text(char *);
98 extern void	aug_save_text1(char *);
99 extern void	aug_save_text2(char *);
100 extern void	aug_save_na(int);
101 extern void	aug_save_user(char *);
102 extern void	aug_save_path(char *);
103 extern int	aug_save_policy(void);
104 extern void	aug_save_afunc(int (*)(int));
105 extern int	aug_audit(void);
106 extern int	aug_na_selected(void);
107 extern int	aug_selected(void);
108 extern int	aug_daemon_session(void);
109 
110 #ifndef HAVE_GETTEXT
111 # define gettext(a)	(a)
112 #endif
113 
114 extern Authctxt *the_authctxt;
115 static AuditInfoTermID ssh_bsm_tid;
116 
117 /* Below is the low-level BSM interface code */
118 
119 /*
120  * aug_get_machine is only required on IPv6 capable machines, we use a
121  * different mechanism in audit_connection_from() for IPv4-only machines.
122  * getaudit_addr() is only present on IPv6 capable machines.
123  */
124 #if defined(HAVE_AUG_GET_MACHINE) || !defined(HAVE_GETAUDIT_ADDR)
125 extern int 	aug_get_machine(char *, u_int32_t *, u_int32_t *);
126 #else
127 static int
128 aug_get_machine(char *host, u_int32_t *addr, u_int32_t *type)
129 {
130 	struct addrinfo *ai;
131 	struct sockaddr_in *in4;
132 	struct sockaddr_in6 *in6;
133 	int ret = 0, r;
134 
135 	if ((r = getaddrinfo(host, NULL, NULL, &ai)) != 0) {
136 		error("BSM audit: getaddrinfo failed for %.100s: %.100s", host,
137 		    r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
138 		return -1;
139 	}
140 
141 	switch (ai->ai_family) {
142 	case AF_INET:
143 		in4 = (struct sockaddr_in *)ai->ai_addr;
144 		*type = AU_IPv4;
145 		memcpy(addr, &in4->sin_addr, sizeof(struct in_addr));
146 		break;
147 #ifdef AU_IPv6
148 	case AF_INET6:
149 		in6 = (struct sockaddr_in6 *)ai->ai_addr;
150 		*type = AU_IPv6;
151 		memcpy(addr, &in6->sin6_addr, sizeof(struct in6_addr));
152 		break;
153 #endif
154 	default:
155 		error("BSM audit: unknown address family for %.100s: %d",
156 		    host, ai->ai_family);
157 		ret = -1;
158 	}
159 	freeaddrinfo(ai);
160 	return ret;
161 }
162 #endif
163 
164 /*
165  * Check if the specified event is selected (enabled) for auditing.
166  * Returns 1 if the event is selected, 0 if not and -1 on failure.
167  */
168 static int
169 selected(char *username, uid_t uid, au_event_t event, int sf)
170 {
171 	int rc, sorf;
172 	char naflags[512];
173 	struct au_mask mask;
174 
175 	mask.am_success = mask.am_failure = 0;
176 	if (uid < 0) {
177 		/* get flags for non-attributable (to a real user) events */
178 		rc = getacna(naflags, sizeof(naflags));
179 		if (rc == 0)
180 			(void) getauditflagsbin(naflags, &mask);
181 	} else
182 		rc = au_user_mask(username, &mask);
183 
184 	sorf = (sf == 0) ? AU_PRS_SUCCESS : AU_PRS_FAILURE;
185 	return(au_preselect(event, &mask, sorf, AU_PRS_REREAD));
186 }
187 
188 static void
189 bsm_audit_record(int typ, char *string, au_event_t event_no)
190 {
191 	int		ad, rc, sel;
192 	uid_t		uid = -1;
193 	gid_t		gid = -1;
194 	pid_t		pid = getpid();
195 	AuditInfoTermID	tid = ssh_bsm_tid;
196 
197 	if (the_authctxt != NULL && the_authctxt->valid) {
198 		uid = the_authctxt->pw->pw_uid;
199 		gid = the_authctxt->pw->pw_gid;
200 	}
201 
202 	rc = (typ == 0) ? 0 : -1;
203 	sel = selected(the_authctxt->user, uid, event_no, rc);
204 	debug3("BSM audit: typ %d rc %d \"%s\"", typ, rc, string);
205 	if (!sel)
206 		return;	/* audit event does not match mask, do not write */
207 
208 	debug3("BSM audit: writing audit new record");
209 	ad = au_open();
210 
211 	(void) au_write(ad, AUToSubjectFunc(uid, uid, gid, uid, gid,
212 	    pid, pid, &tid));
213 	(void) au_write(ad, au_to_text(string));
214 	(void) au_write(ad, AUToReturnFunc(typ, rc));
215 
216 	rc = au_close(ad, AU_TO_WRITE, event_no);
217 	if (rc < 0)
218 		error("BSM audit: %s failed to write \"%s\" record: %s",
219 		    __func__, string, strerror(errno));
220 }
221 
222 static void
223 bsm_audit_session_setup(void)
224 {
225 	int rc;
226 	struct AuditInfoStruct info;
227 	au_mask_t mask;
228 
229 	if (the_authctxt == NULL) {
230 		error("BSM audit: session setup internal error (NULL ctxt)");
231 		return;
232 	}
233 
234 	if (the_authctxt->valid)
235 		info.ai_auid = the_authctxt->pw->pw_uid;
236 	else
237 		info.ai_auid = -1;
238 	info.ai_asid = getpid();
239 	mask.am_success = 0;
240 	mask.am_failure = 0;
241 
242 	(void) au_user_mask(the_authctxt->user, &mask);
243 
244 	info.ai_mask.am_success  = mask.am_success;
245 	info.ai_mask.am_failure  = mask.am_failure;
246 
247 	info.ai_termid = ssh_bsm_tid;
248 
249 	rc = SetAuditFunc(&info, sizeof(info));
250 	if (rc < 0)
251 		error("BSM audit: %s: %s failed: %s", __func__,
252 		    SetAuditFuncText, strerror(errno));
253 }
254 
255 static void
256 bsm_audit_bad_login(const char *what)
257 {
258 	char textbuf[BSM_TEXTBUFSZ];
259 
260 	if (the_authctxt->valid) {
261 		(void) snprintf(textbuf, sizeof (textbuf),
262 			gettext("invalid %s for user %s"),
263 			    what, the_authctxt->user);
264 		bsm_audit_record(4, textbuf, AUE_openssh);
265 	} else {
266 		(void) snprintf(textbuf, sizeof (textbuf),
267 			gettext("invalid user name \"%s\""),
268 			    the_authctxt->user);
269 		bsm_audit_record(3, textbuf, AUE_openssh);
270 	}
271 }
272 
273 /* Below is the sshd audit API code */
274 
275 void
276 audit_connection_from(const char *host, int port)
277 {
278 	AuditInfoTermID *tid = &ssh_bsm_tid;
279 	char buf[1024];
280 
281 	if (cannot_audit(0))
282 		return;
283 	debug3("BSM audit: connection from %.100s port %d", host, port);
284 
285 	/* populate our terminal id structure */
286 #if defined(HAVE_GETAUDIT_ADDR)
287 	tid->at_port = (dev_t)port;
288 	aug_get_machine((char *)host, &(tid->at_addr[0]), &(tid->at_type));
289 	snprintf(buf, sizeof(buf), "%08x %08x %08x %08x", tid->at_addr[0],
290 	    tid->at_addr[1], tid->at_addr[2], tid->at_addr[3]);
291 	debug3("BSM audit: iptype %d machine ID %s", (int)tid->at_type, buf);
292 #else
293 	/* this is used on IPv4-only machines */
294 	tid->port = (dev_t)port;
295 	tid->machine = inet_addr(host);
296 	snprintf(buf, sizeof(buf), "%08x", tid->machine);
297 	debug3("BSM audit: machine ID %s", buf);
298 #endif
299 }
300 
301 void
302 audit_run_command(const char *command)
303 {
304 	/* not implemented */
305 }
306 
307 void
308 audit_session_open(struct logininfo *li)
309 {
310 	/* not implemented */
311 }
312 
313 void
314 audit_session_close(struct logininfo *li)
315 {
316 	/* not implemented */
317 }
318 
319 void
320 audit_event(ssh_audit_event_t event)
321 {
322 	char    textbuf[BSM_TEXTBUFSZ];
323 	static int logged_in = 0;
324 	const char *user = the_authctxt ? the_authctxt->user : "(unknown user)";
325 
326 	if (cannot_audit(0))
327 		return;
328 
329 	switch(event) {
330 	case SSH_AUTH_SUCCESS:
331 		logged_in = 1;
332 		bsm_audit_session_setup();
333 		snprintf(textbuf, sizeof(textbuf),
334 		    gettext("successful login %s"), user);
335 		bsm_audit_record(0, textbuf, AUE_openssh);
336 		break;
337 
338 	case SSH_CONNECTION_CLOSE:
339 		/*
340 		 * We can also get a close event if the user attempted auth
341 		 * but never succeeded.
342 		 */
343 		if (logged_in) {
344 			snprintf(textbuf, sizeof(textbuf),
345 			    gettext("sshd logout %s"), the_authctxt->user);
346 			bsm_audit_record(0, textbuf, AUE_logout);
347 		} else {
348 			debug("%s: connection closed without authentication",
349 			    __func__);
350 		}
351 		break;
352 
353 	case SSH_NOLOGIN:
354 		bsm_audit_record(1,
355 		    gettext("logins disabled by /etc/nologin"), AUE_openssh);
356 		break;
357 
358 	case SSH_LOGIN_EXCEED_MAXTRIES:
359 		snprintf(textbuf, sizeof(textbuf),
360 		    gettext("too many tries for user %s"), the_authctxt->user);
361 		bsm_audit_record(1, textbuf, AUE_openssh);
362 		break;
363 
364 	case SSH_LOGIN_ROOT_DENIED:
365 		bsm_audit_record(2, gettext("not_console"), AUE_openssh);
366 		break;
367 
368 	case SSH_AUTH_FAIL_PASSWD:
369 		bsm_audit_bad_login("password");
370 		break;
371 
372 	case SSH_AUTH_FAIL_KBDINT:
373 		bsm_audit_bad_login("interactive password entry");
374 		break;
375 
376 	default:
377 		debug("%s: unhandled event %d", __func__, event);
378 	}
379 }
380 #endif /* BSM */
381