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
aug_get_machine(char * host,u_int32_t * addr,u_int32_t * type)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
selected(char * username,uid_t uid,au_event_t event,int sf)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
bsm_audit_record(int typ,char * string,au_event_t event_no)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
bsm_audit_session_setup(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
bsm_audit_bad_login(const char * what)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
audit_connection_from(const char * host,int port)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
audit_run_command(const char * command)302 audit_run_command(const char *command)
303 {
304 /* not implemented */
305 }
306
307 void
audit_session_open(struct logininfo * li)308 audit_session_open(struct logininfo *li)
309 {
310 /* not implemented */
311 }
312
313 void
audit_session_close(struct logininfo * li)314 audit_session_close(struct logininfo *li)
315 {
316 /* not implemented */
317 }
318
319 void
audit_event(ssh_audit_event_t event)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