Line data Source code
1 : /*
2 : * EAP-IKEv2 server (RFC 5106)
3 : * Copyright (c) 2007, Jouni Malinen <j@w1.fi>
4 : *
5 : * This software may be distributed under the terms of the BSD license.
6 : * See README for more details.
7 : */
8 :
9 : #include "includes.h"
10 :
11 : #include "common.h"
12 : #include "eap_i.h"
13 : #include "eap_common/eap_ikev2_common.h"
14 : #include "ikev2.h"
15 :
16 :
17 : struct eap_ikev2_data {
18 : struct ikev2_initiator_data ikev2;
19 : enum { MSG, FRAG_ACK, WAIT_FRAG_ACK, DONE, FAIL } state;
20 : struct wpabuf *in_buf;
21 : struct wpabuf *out_buf;
22 : size_t out_used;
23 : size_t fragment_size;
24 : int keys_ready;
25 : u8 keymat[EAP_MSK_LEN + EAP_EMSK_LEN];
26 : int keymat_ok;
27 : };
28 :
29 :
30 2 : static const u8 * eap_ikev2_get_shared_secret(void *ctx, const u8 *IDr,
31 : size_t IDr_len,
32 : size_t *secret_len)
33 : {
34 2 : struct eap_sm *sm = ctx;
35 :
36 2 : if (IDr == NULL) {
37 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: No IDr received - default "
38 : "to user identity from EAP-Identity");
39 0 : IDr = sm->identity;
40 0 : IDr_len = sm->identity_len;
41 : }
42 :
43 4 : if (eap_user_get(sm, IDr, IDr_len, 0) < 0 || sm->user == NULL ||
44 2 : sm->user->password == NULL) {
45 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: No user entry found");
46 0 : return NULL;
47 : }
48 :
49 2 : *secret_len = sm->user->password_len;
50 2 : return sm->user->password;
51 : }
52 :
53 :
54 52 : static const char * eap_ikev2_state_txt(int state)
55 : {
56 52 : switch (state) {
57 : case MSG:
58 26 : return "MSG";
59 : case FRAG_ACK:
60 0 : return "FRAG_ACK";
61 : case WAIT_FRAG_ACK:
62 24 : return "WAIT_FRAG_ACK";
63 : case DONE:
64 2 : return "DONE";
65 : case FAIL:
66 0 : return "FAIL";
67 : default:
68 0 : return "?";
69 : }
70 : }
71 :
72 :
73 26 : static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
74 : {
75 52 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
76 26 : eap_ikev2_state_txt(data->state),
77 : eap_ikev2_state_txt(state));
78 26 : data->state = state;
79 26 : }
80 :
81 :
82 2 : static void * eap_ikev2_init(struct eap_sm *sm)
83 : {
84 : struct eap_ikev2_data *data;
85 :
86 2 : data = os_zalloc(sizeof(*data));
87 2 : if (data == NULL)
88 0 : return NULL;
89 2 : data->state = MSG;
90 2 : data->fragment_size = sm->fragment_size > 0 ? sm->fragment_size :
91 : IKEV2_FRAGMENT_SIZE;
92 2 : data->ikev2.state = SA_INIT;
93 2 : data->ikev2.peer_auth = PEER_AUTH_SECRET;
94 2 : data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
95 2 : if (data->ikev2.key_pad == NULL)
96 0 : goto failed;
97 2 : data->ikev2.key_pad_len = 21;
98 :
99 : /* TODO: make proposals configurable */
100 2 : data->ikev2.proposal.proposal_num = 1;
101 2 : data->ikev2.proposal.integ = AUTH_HMAC_SHA1_96;
102 2 : data->ikev2.proposal.prf = PRF_HMAC_SHA1;
103 2 : data->ikev2.proposal.encr = ENCR_AES_CBC;
104 2 : data->ikev2.proposal.dh = DH_GROUP2_1024BIT_MODP;
105 :
106 2 : data->ikev2.IDi = os_malloc(sm->server_id_len);
107 2 : if (data->ikev2.IDi == NULL)
108 0 : goto failed;
109 2 : os_memcpy(data->ikev2.IDi, sm->server_id, sm->server_id_len);
110 2 : data->ikev2.IDi_len = sm->server_id_len;
111 :
112 2 : data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
113 2 : data->ikev2.cb_ctx = sm;
114 :
115 2 : return data;
116 :
117 : failed:
118 0 : ikev2_initiator_deinit(&data->ikev2);
119 0 : os_free(data);
120 0 : return NULL;
121 : }
122 :
123 :
124 2 : static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
125 : {
126 2 : struct eap_ikev2_data *data = priv;
127 2 : wpabuf_free(data->in_buf);
128 2 : wpabuf_free(data->out_buf);
129 2 : ikev2_initiator_deinit(&data->ikev2);
130 2 : os_free(data);
131 2 : }
132 :
133 :
134 16 : static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
135 : {
136 : struct wpabuf *req;
137 : u8 flags;
138 16 : size_t send_len, plen, icv_len = 0;
139 :
140 16 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
141 :
142 16 : flags = 0;
143 16 : send_len = wpabuf_len(data->out_buf) - data->out_used;
144 16 : if (1 + send_len > data->fragment_size) {
145 12 : send_len = data->fragment_size - 1;
146 12 : flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
147 12 : if (data->out_used == 0) {
148 4 : flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
149 4 : send_len -= 4;
150 : }
151 : }
152 :
153 16 : plen = 1 + send_len;
154 16 : if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
155 4 : plen += 4;
156 16 : if (data->keys_ready) {
157 : const struct ikev2_integ_alg *integ;
158 6 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
159 : "Data");
160 6 : flags |= IKEV2_FLAGS_ICV_INCLUDED;
161 6 : integ = ikev2_get_integ(data->ikev2.proposal.integ);
162 6 : if (integ == NULL) {
163 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
164 : "transform / cannot generate ICV");
165 0 : return NULL;
166 : }
167 6 : icv_len = integ->hash_len;
168 :
169 6 : plen += icv_len;
170 : }
171 16 : req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
172 : EAP_CODE_REQUEST, id);
173 16 : if (req == NULL)
174 0 : return NULL;
175 :
176 16 : wpabuf_put_u8(req, flags); /* Flags */
177 16 : if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
178 4 : wpabuf_put_be32(req, wpabuf_len(data->out_buf));
179 :
180 16 : wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
181 : send_len);
182 16 : data->out_used += send_len;
183 :
184 16 : if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
185 6 : const u8 *msg = wpabuf_head(req);
186 6 : size_t len = wpabuf_len(req);
187 12 : ikev2_integ_hash(data->ikev2.proposal.integ,
188 6 : data->ikev2.keys.SK_ai,
189 : data->ikev2.keys.SK_integ_len,
190 6 : msg, len, wpabuf_put(req, icv_len));
191 : }
192 :
193 16 : if (data->out_used == wpabuf_len(data->out_buf)) {
194 4 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
195 : "(message sent completely)",
196 : (unsigned long) send_len);
197 4 : wpabuf_free(data->out_buf);
198 4 : data->out_buf = NULL;
199 4 : data->out_used = 0;
200 : } else {
201 12 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
202 : "(%lu more to send)", (unsigned long) send_len,
203 12 : (unsigned long) wpabuf_len(data->out_buf) -
204 12 : data->out_used);
205 12 : eap_ikev2_state(data, WAIT_FRAG_ACK);
206 : }
207 :
208 16 : return req;
209 : }
210 :
211 :
212 16 : static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
213 : {
214 16 : struct eap_ikev2_data *data = priv;
215 :
216 16 : switch (data->state) {
217 : case MSG:
218 16 : if (data->out_buf == NULL) {
219 4 : data->out_buf = ikev2_initiator_build(&data->ikev2);
220 4 : if (data->out_buf == NULL) {
221 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
222 : "generate IKEv2 message");
223 0 : return NULL;
224 : }
225 4 : data->out_used = 0;
226 : }
227 : /* pass through */
228 : case WAIT_FRAG_ACK:
229 16 : return eap_ikev2_build_msg(data, id);
230 : case FRAG_ACK:
231 0 : return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
232 : default:
233 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
234 0 : "buildReq", data->state);
235 0 : return NULL;
236 : }
237 : }
238 :
239 :
240 16 : static Boolean eap_ikev2_check(struct eap_sm *sm, void *priv,
241 : struct wpabuf *respData)
242 : {
243 : const u8 *pos;
244 : size_t len;
245 :
246 16 : pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
247 : &len);
248 16 : if (pos == NULL) {
249 0 : wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
250 0 : return TRUE;
251 : }
252 :
253 16 : return FALSE;
254 : }
255 :
256 :
257 16 : static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
258 : const struct wpabuf *respData,
259 : u8 flags, const u8 *pos, const u8 **end,
260 : int frag_ack)
261 : {
262 16 : if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
263 2 : int icv_len = eap_ikev2_validate_icv(
264 : data->ikev2.proposal.integ, &data->ikev2.keys, 0,
265 : respData, pos, *end);
266 2 : if (icv_len < 0)
267 0 : return -1;
268 : /* Hide Integrity Checksum Data from further processing */
269 2 : *end -= icv_len;
270 14 : } else if (data->keys_ready && !frag_ack) {
271 0 : wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
272 : "included integrity checksum");
273 0 : return -1;
274 : }
275 :
276 16 : return 0;
277 : }
278 :
279 :
280 0 : static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
281 : const u8 *buf, size_t len)
282 : {
283 : /* Process continuation of a pending message */
284 0 : if (len > wpabuf_tailroom(data->in_buf)) {
285 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
286 0 : eap_ikev2_state(data, FAIL);
287 0 : return -1;
288 : }
289 :
290 0 : wpabuf_put_data(data->in_buf, buf, len);
291 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
292 : "bytes more", (unsigned long) len,
293 0 : (unsigned long) wpabuf_tailroom(data->in_buf));
294 :
295 0 : return 0;
296 : }
297 :
298 :
299 0 : static int eap_ikev2_process_fragment(struct eap_ikev2_data *data,
300 : u8 flags, u32 message_length,
301 : const u8 *buf, size_t len)
302 : {
303 : /* Process a fragment that is not the last one of the message */
304 0 : if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
305 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
306 : "a fragmented packet");
307 0 : return -1;
308 : }
309 :
310 0 : if (data->in_buf == NULL) {
311 : /* First fragment of the message */
312 0 : data->in_buf = wpabuf_alloc(message_length);
313 0 : if (data->in_buf == NULL) {
314 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
315 : "message");
316 0 : return -1;
317 : }
318 0 : wpabuf_put_data(data->in_buf, buf, len);
319 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
320 : "fragment, waiting for %lu bytes more",
321 : (unsigned long) len,
322 0 : (unsigned long) wpabuf_tailroom(data->in_buf));
323 : }
324 :
325 0 : return 0;
326 : }
327 :
328 :
329 2 : static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
330 : {
331 6 : if (eap_ikev2_derive_keymat(
332 : data->ikev2.proposal.prf, &data->ikev2.keys,
333 2 : data->ikev2.i_nonce, data->ikev2.i_nonce_len,
334 2 : data->ikev2.r_nonce, data->ikev2.r_nonce_len,
335 2 : data->keymat) < 0) {
336 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
337 : "key material");
338 0 : return -1;
339 : }
340 2 : data->keymat_ok = 1;
341 2 : return 0;
342 : }
343 :
344 :
345 16 : static void eap_ikev2_process(struct eap_sm *sm, void *priv,
346 : struct wpabuf *respData)
347 : {
348 16 : struct eap_ikev2_data *data = priv;
349 : const u8 *start, *pos, *end;
350 : size_t len;
351 : u8 flags;
352 16 : u32 message_length = 0;
353 : struct wpabuf tmpbuf;
354 :
355 16 : pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
356 : &len);
357 16 : if (pos == NULL)
358 12 : return; /* Should not happen; message already verified */
359 :
360 16 : start = pos;
361 16 : end = start + len;
362 :
363 16 : if (len == 0) {
364 : /* fragment ack */
365 12 : flags = 0;
366 : } else
367 4 : flags = *pos++;
368 :
369 28 : if (eap_ikev2_process_icv(data, respData, flags, pos, &end,
370 28 : data->state == WAIT_FRAG_ACK && len == 0) < 0)
371 : {
372 0 : eap_ikev2_state(data, FAIL);
373 0 : return;
374 : }
375 :
376 16 : if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
377 0 : if (end - pos < 4) {
378 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
379 0 : eap_ikev2_state(data, FAIL);
380 0 : return;
381 : }
382 0 : message_length = WPA_GET_BE32(pos);
383 0 : pos += 4;
384 :
385 0 : if (message_length < (u32) (end - pos)) {
386 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
387 : "Length (%d; %ld remaining in this msg)",
388 : message_length, (long) (end - pos));
389 0 : eap_ikev2_state(data, FAIL);
390 0 : return;
391 : }
392 : }
393 16 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
394 : "Message Length %u", flags, message_length);
395 :
396 16 : if (data->state == WAIT_FRAG_ACK) {
397 12 : if (len != 0) {
398 0 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
399 : "in WAIT_FRAG_ACK state");
400 0 : eap_ikev2_state(data, FAIL);
401 0 : return;
402 : }
403 12 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
404 12 : eap_ikev2_state(data, MSG);
405 12 : return;
406 : }
407 :
408 4 : if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
409 0 : eap_ikev2_state(data, FAIL);
410 0 : return;
411 : }
412 :
413 4 : if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
414 0 : if (eap_ikev2_process_fragment(data, flags, message_length,
415 0 : pos, end - pos) < 0)
416 0 : eap_ikev2_state(data, FAIL);
417 : else
418 0 : eap_ikev2_state(data, FRAG_ACK);
419 0 : return;
420 4 : } else if (data->state == FRAG_ACK) {
421 0 : wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
422 0 : data->state = MSG;
423 : }
424 :
425 4 : if (data->in_buf == NULL) {
426 : /* Wrap unfragmented messages as wpabuf without extra copy */
427 4 : wpabuf_set(&tmpbuf, pos, end - pos);
428 4 : data->in_buf = &tmpbuf;
429 : }
430 :
431 4 : if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
432 0 : if (data->in_buf == &tmpbuf)
433 0 : data->in_buf = NULL;
434 0 : eap_ikev2_state(data, FAIL);
435 0 : return;
436 : }
437 :
438 4 : switch (data->ikev2.state) {
439 : case SA_AUTH:
440 : /* SA_INIT was sent out, so message have to be
441 : * integrity protected from now on. */
442 2 : data->keys_ready = 1;
443 2 : break;
444 : case IKEV2_DONE:
445 2 : if (data->state == FAIL)
446 0 : break;
447 2 : wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
448 : "successfully");
449 2 : if (eap_ikev2_server_keymat(data))
450 0 : break;
451 2 : eap_ikev2_state(data, DONE);
452 2 : break;
453 : default:
454 0 : break;
455 : }
456 :
457 4 : if (data->in_buf != &tmpbuf)
458 0 : wpabuf_free(data->in_buf);
459 4 : data->in_buf = NULL;
460 : }
461 :
462 :
463 16 : static Boolean eap_ikev2_isDone(struct eap_sm *sm, void *priv)
464 : {
465 16 : struct eap_ikev2_data *data = priv;
466 16 : return data->state == DONE || data->state == FAIL;
467 : }
468 :
469 :
470 2 : static Boolean eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
471 : {
472 2 : struct eap_ikev2_data *data = priv;
473 4 : return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
474 2 : data->keymat_ok;
475 : }
476 :
477 :
478 2 : static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
479 : {
480 2 : struct eap_ikev2_data *data = priv;
481 : u8 *key;
482 :
483 2 : if (data->state != DONE || !data->keymat_ok)
484 0 : return NULL;
485 :
486 2 : key = os_malloc(EAP_MSK_LEN);
487 2 : if (key) {
488 2 : os_memcpy(key, data->keymat, EAP_MSK_LEN);
489 2 : *len = EAP_MSK_LEN;
490 : }
491 :
492 2 : return key;
493 : }
494 :
495 :
496 0 : static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
497 : {
498 0 : struct eap_ikev2_data *data = priv;
499 : u8 *key;
500 :
501 0 : if (data->state != DONE || !data->keymat_ok)
502 0 : return NULL;
503 :
504 0 : key = os_malloc(EAP_EMSK_LEN);
505 0 : if (key) {
506 0 : os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
507 0 : *len = EAP_EMSK_LEN;
508 : }
509 :
510 0 : return key;
511 : }
512 :
513 :
514 1 : int eap_server_ikev2_register(void)
515 : {
516 : struct eap_method *eap;
517 : int ret;
518 :
519 1 : eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
520 : EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
521 : "IKEV2");
522 1 : if (eap == NULL)
523 0 : return -1;
524 :
525 1 : eap->init = eap_ikev2_init;
526 1 : eap->reset = eap_ikev2_reset;
527 1 : eap->buildReq = eap_ikev2_buildReq;
528 1 : eap->check = eap_ikev2_check;
529 1 : eap->process = eap_ikev2_process;
530 1 : eap->isDone = eap_ikev2_isDone;
531 1 : eap->getKey = eap_ikev2_getKey;
532 1 : eap->isSuccess = eap_ikev2_isSuccess;
533 1 : eap->get_emsk = eap_ikev2_get_emsk;
534 :
535 1 : ret = eap_server_method_register(eap);
536 1 : if (ret)
537 0 : eap_server_method_free(eap);
538 1 : return ret;
539 : }
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