xref: /freebsd/contrib/bsnmp/snmp_usm/usm_snmp.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
1 /*-
2  * Copyright (c) 2010 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Shteryana Sotirova Shopova under
6  * sponsorship from the FreeBSD Foundation.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND 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 THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR 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, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 #include <sys/queue.h>
32 #include <sys/types.h>
33 
34 #include <errno.h>
35 #include <stdarg.h>
36 #include <stdlib.h>
37 #include <stdio.h>
38 #include <stdint.h>
39 #include <string.h>
40 #include <syslog.h>
41 
42 #include "asn1.h"
43 #include "snmp.h"
44 #include "snmpmod.h"
45 
46 #include "usm_tree.h"
47 #include "usm_oid.h"
48 
49 static struct lmodule *usm_module;
50 /* For the registration. */
51 static const struct asn_oid oid_usm = OIDX_snmpUsmMIB;
52 
53 static const struct asn_oid oid_usmNoAuthProtocol = OIDX_usmNoAuthProtocol;
54 static const struct asn_oid oid_usmHMACMD5AuthProtocol =		\
55     OIDX_usmHMACMD5AuthProtocol;
56 static const struct asn_oid oid_usmHMACSHAAuthProtocol =		\
57     OIDX_usmHMACSHAAuthProtocol;
58 
59 static const struct asn_oid oid_usmNoPrivProtocol = OIDX_usmNoPrivProtocol;
60 static const struct asn_oid oid_usmDESPrivProtocol = OIDX_usmDESPrivProtocol;
61 static const struct asn_oid oid_usmAesCfb128Protocol = OIDX_usmAesCfb128Protocol;
62 
63 static const struct asn_oid oid_usmUserSecurityName = OIDX_usmUserSecurityName;
64 
65 /* The registration. */
66 static uint reg_usm;
67 
68 static int32_t usm_lock;
69 
70 static struct usm_user *	usm_get_user(const struct asn_oid *, uint);
71 static struct usm_user *	usm_get_next_user(const struct asn_oid *, uint);
72 static void	usm_append_userindex(struct asn_oid *, uint,
73     const struct usm_user *);
74 static int	usm_user_index_decode(const struct asn_oid *, uint, uint8_t *,
75     uint32_t *, char *);
76 
77 int
78 op_usm_stats(struct snmp_context *ctx __unused, struct snmp_value *val,
79     uint32_t sub __unused, uint32_t iidx __unused, enum snmp_op op)
80 {
81 	struct snmpd_usmstat *usmstats;
82 
83 	if (op == SNMP_OP_SET)
84 		return (SNMP_ERR_NOT_WRITEABLE);
85 
86 	if ((usmstats = bsnmpd_get_usm_stats()) == NULL)
87 		return (SNMP_ERR_GENERR);
88 
89 	if (op == SNMP_OP_GET) {
90 		switch (val->var.subs[sub - 1]) {
91 		case LEAF_usmStatsUnsupportedSecLevels:
92 			val->v.uint32 = usmstats->unsupported_seclevels;
93 			break;
94 		case LEAF_usmStatsNotInTimeWindows:
95 			val->v.uint32 = usmstats->not_in_time_windows;
96 			break;
97 		case LEAF_usmStatsUnknownUserNames:
98 			val->v.uint32 = usmstats->unknown_users;
99 			break;
100 		case LEAF_usmStatsUnknownEngineIDs:
101 			val->v.uint32 = usmstats->unknown_engine_ids;
102 			break;
103 		case LEAF_usmStatsWrongDigests:
104 			val->v.uint32 = usmstats->wrong_digests;
105 			break;
106 		case LEAF_usmStatsDecryptionErrors:
107 			val->v.uint32 = usmstats->decrypt_errors;
108 			break;
109 		default:
110 			return (SNMP_ERR_NOSUCHNAME);
111 		}
112 		return (SNMP_ERR_NOERROR);
113 	}
114 	abort();
115 }
116 
117 int
118 op_usm_lock(struct snmp_context *ctx __unused, struct snmp_value *val,
119     uint32_t sub, uint32_t iidx __unused, enum snmp_op op)
120 {
121 	if (val->var.subs[sub - 1] != LEAF_usmUserSpinLock)
122 		return (SNMP_ERR_NOSUCHNAME);
123 
124 	switch (op) {
125 	case SNMP_OP_GET:
126 		if (++usm_lock == INT32_MAX)
127 			usm_lock = 0;
128 		val->v.integer = usm_lock;
129 		break;
130 	case SNMP_OP_GETNEXT:
131 		abort();
132 	case SNMP_OP_SET:
133 		if (val->v.integer != usm_lock)
134 			return (SNMP_ERR_INCONS_VALUE);
135 		break;
136 	case SNMP_OP_ROLLBACK:
137 		/* FALLTHROUGH */
138 	case SNMP_OP_COMMIT:
139 		break;
140 	}
141 
142 	return (SNMP_ERR_NOERROR);
143 }
144 
145 int
146 op_usm_users(struct snmp_context *ctx, struct snmp_value *val,
147     uint32_t sub, uint32_t iidx __unused, enum snmp_op op)
148 {
149 	uint32_t elen;
150 	struct usm_user *uuser, *clone;
151 	char uname[SNMP_ADM_STR32_SIZ];
152 	uint8_t eid[SNMP_ENGINE_ID_SIZ];
153 
154 	switch (op) {
155 	case SNMP_OP_GET:
156 		if ((uuser = usm_get_user(&val->var, sub)) == NULL)
157 			return (SNMP_ERR_NOSUCHNAME);
158 		break;
159 
160 	case SNMP_OP_GETNEXT:
161 		if ((uuser = usm_get_next_user(&val->var, sub)) == NULL)
162 			return (SNMP_ERR_NOSUCHNAME);
163 		usm_append_userindex(&val->var, sub, uuser);
164 		break;
165 
166 	case SNMP_OP_SET:
167 		if ((uuser = usm_get_user(&val->var, sub)) == NULL &&
168 		    val->var.subs[sub - 1] != LEAF_usmUserStatus &&
169 		    val->var.subs[sub - 1] != LEAF_usmUserCloneFrom)
170 				return (SNMP_ERR_NOSUCHNAME);
171 
172 		if (community != COMM_INITIALIZE &&
173 		    uuser->type == StorageType_readOnly)
174 			return (SNMP_ERR_NOT_WRITEABLE);
175 
176 		switch (val->var.subs[sub - 1]) {
177 		case LEAF_usmUserSecurityName:
178 			return (SNMP_ERR_NOT_WRITEABLE);
179 
180 		case LEAF_usmUserCloneFrom:
181 			if (uuser != NULL || usm_user_index_decode(&val->var,
182 			    sub, eid, &elen, uname) < 0 ||
183 			    !(asn_is_suboid(&oid_usmUserSecurityName, &val->v.oid)))
184 				return (SNMP_ERR_WRONG_VALUE);
185 			if ((clone = usm_get_user(&val->v.oid, sub)) == NULL)
186 				return (SNMP_ERR_INCONS_VALUE);
187 			if ((uuser = usm_new_user(eid, elen, uname)) == NULL)
188 				return (SNMP_ERR_GENERR);
189 			uuser->status = RowStatus_notReady;
190 			if (community != COMM_INITIALIZE)
191 				uuser->type = StorageType_volatile;
192 			else
193 				uuser->type = StorageType_readOnly;
194 
195 			uuser->suser.auth_proto = clone->suser.auth_proto;
196 			uuser->suser.priv_proto = clone->suser.priv_proto;
197 			memcpy(uuser->suser.auth_key, clone->suser.auth_key,
198 			    sizeof(uuser->suser.auth_key));
199 			memcpy(uuser->suser.priv_key, clone->suser.priv_key,
200 			    sizeof(uuser->suser.priv_key));
201 			ctx->scratch->int1 = RowStatus_createAndWait;
202 			break;
203 
204 		case LEAF_usmUserAuthProtocol:
205 			ctx->scratch->int1 = uuser->suser.auth_proto;
206 			if (asn_compare_oid(&oid_usmNoAuthProtocol,
207 			    &val->v.oid) == 0)
208 				uuser->suser.auth_proto = SNMP_AUTH_NOAUTH;
209 			else if (asn_compare_oid(&oid_usmHMACMD5AuthProtocol,
210 			    &val->v.oid) == 0)
211 				uuser->suser.auth_proto = SNMP_AUTH_HMAC_MD5;
212 			else if (asn_compare_oid(&oid_usmHMACSHAAuthProtocol,
213 			    &val->v.oid) == 0)
214 				uuser->suser.auth_proto = SNMP_AUTH_HMAC_SHA;
215 			else
216 				return (SNMP_ERR_WRONG_VALUE);
217 			break;
218 
219 		case LEAF_usmUserAuthKeyChange:
220 		case LEAF_usmUserOwnAuthKeyChange:
221 			if (val->var.subs[sub - 1] ==
222 			    LEAF_usmUserOwnAuthKeyChange &&
223 			    (usm_user == NULL || strcmp(uuser->suser.sec_name,
224 			    usm_user->suser.sec_name) != 0))
225 				return (SNMP_ERR_NO_ACCESS);
226 			if (val->v.octetstring.len > SNMP_AUTH_KEY_SIZ)
227 				return (SNMP_ERR_INCONS_VALUE);
228 			ctx->scratch->ptr1 = malloc(SNMP_AUTH_KEY_SIZ);
229 			if (ctx->scratch->ptr1 == NULL)
230 				return (SNMP_ERR_GENERR);
231 			memcpy(ctx->scratch->ptr1, uuser->suser.auth_key,
232 			    SNMP_AUTH_KEY_SIZ);
233 			memcpy(uuser->suser.auth_key, val->v.octetstring.octets,
234 			    val->v.octetstring.len);
235 			break;
236 
237 		case LEAF_usmUserPrivProtocol:
238 			ctx->scratch->int1 = uuser->suser.priv_proto;
239 			if (asn_compare_oid(&oid_usmNoPrivProtocol,
240 			    &val->v.oid) == 0)
241 				uuser->suser.priv_proto = SNMP_PRIV_NOPRIV;
242 			else if (asn_compare_oid(&oid_usmDESPrivProtocol,
243 			    &val->v.oid) == 0)
244 				uuser->suser.priv_proto = SNMP_PRIV_DES;
245 			else if (asn_compare_oid(&oid_usmAesCfb128Protocol,
246 			    &val->v.oid) == 0)
247 				uuser->suser.priv_proto = SNMP_PRIV_AES;
248 			else
249 				return (SNMP_ERR_WRONG_VALUE);
250 			break;
251 
252 		case LEAF_usmUserPrivKeyChange:
253 		case LEAF_usmUserOwnPrivKeyChange:
254 			if (val->var.subs[sub - 1] ==
255 			    LEAF_usmUserOwnPrivKeyChange &&
256 			    (usm_user == NULL || strcmp(uuser->suser.sec_name,
257 			    usm_user->suser.sec_name) != 0))
258 				return (SNMP_ERR_NO_ACCESS);
259 			if (val->v.octetstring.len > SNMP_PRIV_KEY_SIZ)
260 				return (SNMP_ERR_INCONS_VALUE);
261 			ctx->scratch->ptr1 = malloc(SNMP_PRIV_KEY_SIZ);
262 			if (ctx->scratch->ptr1 == NULL)
263 				return (SNMP_ERR_GENERR);
264 			memcpy(ctx->scratch->ptr1, uuser->suser.priv_key,
265 			    sizeof(uuser->suser.priv_key));
266 			memcpy(uuser->suser.priv_key, val->v.octetstring.octets,
267 			    val->v.octetstring.len);
268 			break;
269 
270 		case LEAF_usmUserPublic:
271 			if (val->v.octetstring.len > SNMP_ADM_STR32_SIZ)
272 				return (SNMP_ERR_INCONS_VALUE);
273 			if (uuser->user_public_len > 0) {
274 				ctx->scratch->ptr2 =
275 				    malloc(uuser->user_public_len);
276 				if (ctx->scratch->ptr2 == NULL)
277 					return (SNMP_ERR_GENERR);
278 				memcpy(ctx->scratch->ptr2, uuser->user_public,
279 			 	   uuser->user_public_len);
280 				ctx->scratch->int2 = uuser->user_public_len;
281 			}
282 			if (val->v.octetstring.len > 0) {
283 				memcpy(uuser->user_public,
284 				    val->v.octetstring.octets,
285 				    val->v.octetstring.len);
286 				uuser->user_public_len = val->v.octetstring.len;
287 			} else {
288 				memset(uuser->user_public, 0,
289 				    sizeof(uuser->user_public));
290 				uuser->user_public_len = 0;
291 			}
292 			break;
293 
294 		case LEAF_usmUserStorageType:
295 			return (SNMP_ERR_INCONS_VALUE);
296 
297 		case LEAF_usmUserStatus:
298 			if (uuser == NULL) {
299 				if (val->v.integer != RowStatus_createAndWait ||
300 				    usm_user_index_decode(&val->var, sub, eid,
301 				    &elen, uname) < 0)
302 					return (SNMP_ERR_INCONS_VALUE);
303 				uuser = usm_new_user(eid, elen, uname);
304 				if (uuser == NULL)
305 					return (SNMP_ERR_GENERR);
306 				uuser->status = RowStatus_notReady;
307 				if (community != COMM_INITIALIZE)
308 					uuser->type = StorageType_volatile;
309 				else
310 					uuser->type = StorageType_readOnly;
311 			} else if (val->v.integer != RowStatus_active &&
312 			    val->v.integer != RowStatus_destroy)
313 				return (SNMP_ERR_INCONS_VALUE);
314 
315 			uuser->status = val->v.integer;
316 			break;
317 		}
318 		return (SNMP_ERR_NOERROR);
319 
320 	case SNMP_OP_COMMIT:
321 		switch (val->var.subs[sub - 1]) {
322 		case LEAF_usmUserAuthKeyChange:
323 		case LEAF_usmUserOwnAuthKeyChange:
324 		case LEAF_usmUserPrivKeyChange:
325 		case LEAF_usmUserOwnPrivKeyChange:
326 			free(ctx->scratch->ptr1);
327 			break;
328 		case LEAF_usmUserPublic:
329 			if (ctx->scratch->ptr2 != NULL)
330 				free(ctx->scratch->ptr2);
331 			break;
332 		case LEAF_usmUserStatus:
333 			if (val->v.integer != RowStatus_destroy)
334 				break;
335 			if ((uuser = usm_get_user(&val->var, sub)) == NULL)
336 				return (SNMP_ERR_GENERR);
337 			usm_delete_user(uuser);
338 			break;
339 		default:
340 			break;
341 		}
342 		return (SNMP_ERR_NOERROR);
343 
344 	case SNMP_OP_ROLLBACK:
345 		if ((uuser = usm_get_user(&val->var, sub)) == NULL)
346 			return (SNMP_ERR_GENERR);
347 		switch (val->var.subs[sub - 1]) {
348 		case LEAF_usmUserAuthProtocol:
349 			uuser->suser.auth_proto = ctx->scratch->int1;
350 			break;
351 		case LEAF_usmUserAuthKeyChange:
352 		case LEAF_usmUserOwnAuthKeyChange:
353 			memcpy(uuser->suser.auth_key, ctx->scratch->ptr1,
354 			    sizeof(uuser->suser.auth_key));
355 			free(ctx->scratch->ptr1);
356 			break;
357 		case LEAF_usmUserPrivProtocol:
358 			uuser->suser.priv_proto = ctx->scratch->int1;
359 			break;
360 		case LEAF_usmUserPrivKeyChange:
361 		case LEAF_usmUserOwnPrivKeyChange:
362 			memcpy(uuser->suser.priv_key, ctx->scratch->ptr1,
363 			    sizeof(uuser->suser.priv_key));
364 			free(ctx->scratch->ptr1);
365 			break;
366 		case LEAF_usmUserPublic:
367 			if (ctx->scratch->ptr2 != NULL) {
368 				memcpy(uuser->user_public, ctx->scratch->ptr2,
369 			 	   ctx->scratch->int2);
370 				uuser->user_public_len = ctx->scratch->int2;
371 				free(ctx->scratch->ptr2);
372 			} else {
373 				memset(uuser->user_public, 0,
374 				    sizeof(uuser->user_public));
375 				uuser->user_public_len = 0;
376 			}
377 			break;
378 		case LEAF_usmUserCloneFrom:
379 		case LEAF_usmUserStatus:
380 			if (ctx->scratch->int1 == RowStatus_createAndWait)
381 				usm_delete_user(uuser);
382 			break;
383 		default:
384 			break;
385 		}
386 		return (SNMP_ERR_NOERROR);
387 
388 	default:
389 		abort();
390 	}
391 
392 	switch (val->var.subs[sub - 1]) {
393 	case LEAF_usmUserSecurityName:
394 		return (string_get(val, uuser->suser.sec_name, -1));
395 	case LEAF_usmUserCloneFrom:
396 		memcpy(&val->v.oid, &oid_zeroDotZero, sizeof(oid_zeroDotZero));
397 		break;
398 	case LEAF_usmUserAuthProtocol:
399 		switch (uuser->suser.auth_proto) {
400 		case SNMP_AUTH_HMAC_MD5:
401 			memcpy(&val->v.oid, &oid_usmHMACMD5AuthProtocol,
402 			    sizeof(oid_usmHMACMD5AuthProtocol));
403 			break;
404 		case SNMP_AUTH_HMAC_SHA:
405 			memcpy(&val->v.oid, &oid_usmHMACSHAAuthProtocol,
406 			    sizeof(oid_usmHMACSHAAuthProtocol));
407 			break;
408 		default:
409 			memcpy(&val->v.oid, &oid_usmNoAuthProtocol,
410 			    sizeof(oid_usmNoAuthProtocol));
411 			break;
412 		}
413 		break;
414 	case LEAF_usmUserAuthKeyChange:
415 	case LEAF_usmUserOwnAuthKeyChange:
416 		return (string_get(val, (char *)uuser->suser.auth_key, 0));
417 	case LEAF_usmUserPrivProtocol:
418 		switch (uuser->suser.priv_proto) {
419 		case SNMP_PRIV_DES:
420 			memcpy(&val->v.oid, &oid_usmDESPrivProtocol,
421 			    sizeof(oid_usmDESPrivProtocol));
422 			break;
423 		case SNMP_PRIV_AES:
424 			memcpy(&val->v.oid, &oid_usmAesCfb128Protocol,
425 			    sizeof(oid_usmAesCfb128Protocol));
426 			break;
427 		default:
428 			memcpy(&val->v.oid, &oid_usmNoPrivProtocol,
429 			    sizeof(oid_usmNoPrivProtocol));
430 			break;
431 		}
432 		break;
433 	case LEAF_usmUserPrivKeyChange:
434 	case LEAF_usmUserOwnPrivKeyChange:
435 		return (string_get(val, (char *)uuser->suser.priv_key, 0));
436 	case LEAF_usmUserPublic:
437 		return (string_get(val, uuser->user_public,
438 		    uuser->user_public_len));
439 	case LEAF_usmUserStorageType:
440 		val->v.integer = uuser->type;
441 		break;
442 	case LEAF_usmUserStatus:
443 		val->v.integer = uuser->status;
444 		break;
445 	}
446 
447 	return (SNMP_ERR_NOERROR);
448 }
449 
450 static int
451 usm_user_index_decode(const struct asn_oid *oid, uint sub, uint8_t *engine,
452     uint32_t *elen, char *uname)
453 {
454 	uint32_t i, nlen;
455 	int uname_off;
456 
457 	if (oid->subs[sub] > SNMP_ENGINE_ID_SIZ)
458 		return (-1);
459 
460 	for (i = 0; i < oid->subs[sub]; i++)
461 		engine[i] = oid->subs[sub + i + 1];
462 	*elen = i;
463 
464 	uname_off = sub + oid->subs[sub] + 1;
465 	if ((nlen = oid->subs[uname_off]) >= SNMP_ADM_STR32_SIZ)
466 		return (-1);
467 
468 	for (i = 0; i < nlen; i++)
469 		uname[i] = oid->subs[uname_off + i + 1];
470 	uname[nlen] = '\0';
471 
472 	return (0);
473 }
474 
475 static void
476 usm_append_userindex(struct asn_oid *oid, uint sub,
477     const struct usm_user *uuser)
478 {
479 	uint32_t i;
480 
481 	oid->len = sub + uuser->user_engine_len + strlen(uuser->suser.sec_name);
482 	oid->len += 2;
483 	oid->subs[sub] = uuser->user_engine_len;
484 	for (i = 1; i < uuser->user_engine_len + 1; i++)
485 		oid->subs[sub + i] = uuser->user_engine_id[i - 1];
486 
487 	sub += uuser->user_engine_len + 1;
488 	oid->subs[sub] = strlen(uuser->suser.sec_name);
489 	for (i = 1; i <= oid->subs[sub]; i++)
490 		oid->subs[sub + i] = uuser->suser.sec_name[i - 1];
491 }
492 
493 static struct usm_user *
494 usm_get_user(const struct asn_oid *oid, uint sub)
495 {
496 	uint32_t enginelen;
497 	char username[SNMP_ADM_STR32_SIZ];
498 	uint8_t engineid[SNMP_ENGINE_ID_SIZ];
499 
500 	if (usm_user_index_decode(oid, sub, engineid, &enginelen, username) < 0)
501 		return (NULL);
502 
503 	return (usm_find_user(engineid, enginelen, username));
504 }
505 
506 static struct usm_user *
507 usm_get_next_user(const struct asn_oid *oid, uint sub)
508 {
509 	uint32_t enginelen;
510 	char username[SNMP_ADM_STR32_SIZ];
511 	uint8_t engineid[SNMP_ENGINE_ID_SIZ];
512 	struct usm_user *uuser;
513 
514 	if (oid->len - sub == 0)
515 		return (usm_first_user());
516 
517 	if (usm_user_index_decode(oid, sub, engineid, &enginelen, username) < 0)
518 		return (NULL);
519 
520 	if ((uuser = usm_find_user(engineid, enginelen, username)) != NULL)
521 		return (usm_next_user(uuser));
522 
523 	return (NULL);
524 }
525 
526 /*
527  * USM snmp module initialization hook.
528  * Returns 0 on success, < 0 on error.
529  */
530 static int
531 usm_init(struct lmodule * mod, int argc __unused, char *argv[] __unused)
532 {
533 	usm_module = mod;
534 	usm_lock = random();
535 	bsnmpd_reset_usm_stats();
536 	return (0);
537 }
538 
539 /*
540  * USM snmp module finalization hook.
541  */
542 static int
543 usm_fini(void)
544 {
545 	usm_flush_users();
546 	or_unregister(reg_usm);
547 
548 	return (0);
549 }
550 
551 /*
552  * USM snmp module start operation.
553  */
554 static void
555 usm_start(void)
556 {
557 	reg_usm = or_register(&oid_usm,
558 	    "The MIB module for managing SNMP User-Based Security Model.",
559 	    usm_module);
560 }
561 
562 static void
563 usm_dump(void)
564 {
565 	struct usm_user *uuser;
566 	struct snmpd_usmstat *usmstats;
567 	const char *const authstr[] = {
568 		"noauth",
569 		"md5",
570 		"sha",
571 		NULL
572 	};
573 	const char *const privstr[] = {
574 		"nopriv",
575 		"des",
576 		"aes",
577 		NULL
578 	};
579 
580 	if ((usmstats = bsnmpd_get_usm_stats()) != NULL) {
581 		syslog(LOG_ERR, "UnsupportedSecLevels\t\t%u",
582 		    usmstats->unsupported_seclevels);
583 		syslog(LOG_ERR, "NotInTimeWindows\t\t%u",
584 		    usmstats->not_in_time_windows);
585 		syslog(LOG_ERR, "UnknownUserNames\t\t%u",
586 		    usmstats->unknown_users);
587 		syslog(LOG_ERR, "UnknownEngineIDs\t\t%u",
588 		    usmstats->unknown_engine_ids);
589 		syslog(LOG_ERR, "WrongDigests\t\t%u",
590 		    usmstats->wrong_digests);
591 		syslog(LOG_ERR, "DecryptionErrors\t\t%u",
592 		    usmstats->decrypt_errors);
593 	}
594 
595 	syslog(LOG_ERR, "USM users");
596 	for (uuser = usm_first_user(); uuser != NULL;
597 	    (uuser = usm_next_user(uuser)))
598 		syslog(LOG_ERR, "user %s\t\t%s, %s", uuser->suser.sec_name,
599 		    authstr[uuser->suser.auth_proto],
600 		    privstr[uuser->suser.priv_proto]);
601 }
602 
603 const char usm_comment[] = \
604 "This module implements SNMP User-based Security Model defined in RFC 3414.";
605 
606 const struct snmp_module config = {
607 	.comment =	usm_comment,
608 	.init =		usm_init,
609 	.fini =		usm_fini,
610 	.start =	usm_start,
611 	.tree =		usm_ctree,
612 	.dump =		usm_dump,
613 	.tree_size =	usm_CTREE_SIZE,
614 };
615