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
eap_ikev2_get_shared_secret(void * ctx,const u8 * IDr,size_t IDr_len,size_t * secret_len)30 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 struct eap_sm *sm = ctx;
35
36 if (IDr == NULL) {
37 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No IDr received - default "
38 "to user identity from EAP-Identity");
39 IDr = sm->identity;
40 IDr_len = sm->identity_len;
41 }
42
43 if (eap_user_get(sm, IDr, IDr_len, 0) < 0 || sm->user == NULL ||
44 sm->user->password == NULL) {
45 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No user entry found");
46 return NULL;
47 }
48
49 *secret_len = sm->user->password_len;
50 return sm->user->password;
51 }
52
53
eap_ikev2_state_txt(int state)54 static const char * eap_ikev2_state_txt(int state)
55 {
56 switch (state) {
57 case MSG:
58 return "MSG";
59 case FRAG_ACK:
60 return "FRAG_ACK";
61 case WAIT_FRAG_ACK:
62 return "WAIT_FRAG_ACK";
63 case DONE:
64 return "DONE";
65 case FAIL:
66 return "FAIL";
67 default:
68 return "?";
69 }
70 }
71
72
eap_ikev2_state(struct eap_ikev2_data * data,int state)73 static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
74 {
75 wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
76 eap_ikev2_state_txt(data->state),
77 eap_ikev2_state_txt(state));
78 data->state = state;
79 }
80
81
eap_ikev2_init(struct eap_sm * sm)82 static void * eap_ikev2_init(struct eap_sm *sm)
83 {
84 struct eap_ikev2_data *data;
85
86 data = os_zalloc(sizeof(*data));
87 if (data == NULL)
88 return NULL;
89 data->state = MSG;
90 data->fragment_size = sm->fragment_size > 0 ? sm->fragment_size :
91 IKEV2_FRAGMENT_SIZE;
92 data->ikev2.state = SA_INIT;
93 data->ikev2.peer_auth = PEER_AUTH_SECRET;
94 data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
95 if (data->ikev2.key_pad == NULL)
96 goto failed;
97 data->ikev2.key_pad_len = 21;
98
99 /* TODO: make proposals configurable */
100 data->ikev2.proposal.proposal_num = 1;
101 data->ikev2.proposal.integ = AUTH_HMAC_SHA1_96;
102 data->ikev2.proposal.prf = PRF_HMAC_SHA1;
103 data->ikev2.proposal.encr = ENCR_AES_CBC;
104 data->ikev2.proposal.dh = DH_GROUP2_1024BIT_MODP;
105
106 data->ikev2.IDi = os_malloc(sm->server_id_len);
107 if (data->ikev2.IDi == NULL)
108 goto failed;
109 os_memcpy(data->ikev2.IDi, sm->server_id, sm->server_id_len);
110 data->ikev2.IDi_len = sm->server_id_len;
111
112 data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
113 data->ikev2.cb_ctx = sm;
114
115 return data;
116
117 failed:
118 ikev2_initiator_deinit(&data->ikev2);
119 os_free(data);
120 return NULL;
121 }
122
123
eap_ikev2_reset(struct eap_sm * sm,void * priv)124 static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
125 {
126 struct eap_ikev2_data *data = priv;
127 wpabuf_free(data->in_buf);
128 wpabuf_free(data->out_buf);
129 ikev2_initiator_deinit(&data->ikev2);
130 bin_clear_free(data, sizeof(*data));
131 }
132
133
eap_ikev2_build_msg(struct eap_ikev2_data * data,u8 id)134 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
135 {
136 struct wpabuf *req;
137 u8 flags;
138 size_t send_len, plen, icv_len = 0;
139
140 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
141
142 flags = 0;
143 send_len = wpabuf_len(data->out_buf) - data->out_used;
144 if (1 + send_len > data->fragment_size) {
145 send_len = data->fragment_size - 1;
146 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
147 if (data->out_used == 0) {
148 flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
149 send_len -= 4;
150 }
151 }
152
153 plen = 1 + send_len;
154 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
155 plen += 4;
156 if (data->keys_ready) {
157 const struct ikev2_integ_alg *integ;
158 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
159 "Data");
160 flags |= IKEV2_FLAGS_ICV_INCLUDED;
161 integ = ikev2_get_integ(data->ikev2.proposal.integ);
162 if (integ == NULL) {
163 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
164 "transform / cannot generate ICV");
165 return NULL;
166 }
167 icv_len = integ->hash_len;
168
169 plen += icv_len;
170 }
171 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
172 EAP_CODE_REQUEST, id);
173 if (req == NULL)
174 return NULL;
175
176 wpabuf_put_u8(req, flags); /* Flags */
177 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
178 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
179
180 wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
181 send_len);
182 data->out_used += send_len;
183
184 if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
185 const u8 *msg = wpabuf_head(req);
186 size_t len = wpabuf_len(req);
187 ikev2_integ_hash(data->ikev2.proposal.integ,
188 data->ikev2.keys.SK_ai,
189 data->ikev2.keys.SK_integ_len,
190 msg, len, wpabuf_put(req, icv_len));
191 }
192
193 if (data->out_used == wpabuf_len(data->out_buf)) {
194 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
195 "(message sent completely)",
196 (unsigned long) send_len);
197 wpabuf_free(data->out_buf);
198 data->out_buf = NULL;
199 data->out_used = 0;
200 } else {
201 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
202 "(%lu more to send)", (unsigned long) send_len,
203 (unsigned long) wpabuf_len(data->out_buf) -
204 data->out_used);
205 eap_ikev2_state(data, WAIT_FRAG_ACK);
206 }
207
208 return req;
209 }
210
211
eap_ikev2_buildReq(struct eap_sm * sm,void * priv,u8 id)212 static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
213 {
214 struct eap_ikev2_data *data = priv;
215
216 switch (data->state) {
217 case MSG:
218 if (data->out_buf == NULL) {
219 data->out_buf = ikev2_initiator_build(&data->ikev2);
220 if (data->out_buf == NULL) {
221 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
222 "generate IKEv2 message");
223 return NULL;
224 }
225 data->out_used = 0;
226 }
227 /* pass through */
228 case WAIT_FRAG_ACK:
229 return eap_ikev2_build_msg(data, id);
230 case FRAG_ACK:
231 return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
232 default:
233 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
234 "buildReq", data->state);
235 return NULL;
236 }
237 }
238
239
eap_ikev2_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)240 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 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
247 &len);
248 if (pos == NULL) {
249 wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
250 return TRUE;
251 }
252
253 return FALSE;
254 }
255
256
eap_ikev2_process_icv(struct eap_ikev2_data * data,const struct wpabuf * respData,u8 flags,const u8 * pos,const u8 ** end,int frag_ack)257 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 if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
263 int icv_len = eap_ikev2_validate_icv(
264 data->ikev2.proposal.integ, &data->ikev2.keys, 0,
265 respData, pos, *end);
266 if (icv_len < 0)
267 return -1;
268 /* Hide Integrity Checksum Data from further processing */
269 *end -= icv_len;
270 } else if (data->keys_ready && !frag_ack) {
271 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
272 "included integrity checksum");
273 return -1;
274 }
275
276 return 0;
277 }
278
279
eap_ikev2_process_cont(struct eap_ikev2_data * data,const u8 * buf,size_t len)280 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 if (len > wpabuf_tailroom(data->in_buf)) {
285 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
286 eap_ikev2_state(data, FAIL);
287 return -1;
288 }
289
290 wpabuf_put_data(data->in_buf, buf, len);
291 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
292 "bytes more", (unsigned long) len,
293 (unsigned long) wpabuf_tailroom(data->in_buf));
294
295 return 0;
296 }
297
298
eap_ikev2_process_fragment(struct eap_ikev2_data * data,u8 flags,u32 message_length,const u8 * buf,size_t len)299 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 if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
305 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
306 "a fragmented packet");
307 return -1;
308 }
309
310 if (data->in_buf == NULL) {
311 /* First fragment of the message */
312 if (message_length > 50000) {
313 /* Limit maximum memory allocation */
314 wpa_printf(MSG_DEBUG,
315 "EAP-IKEV2: Ignore too long message");
316 return -1;
317 }
318 data->in_buf = wpabuf_alloc(message_length);
319 if (data->in_buf == NULL) {
320 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
321 "message");
322 return -1;
323 }
324 wpabuf_put_data(data->in_buf, buf, len);
325 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
326 "fragment, waiting for %lu bytes more",
327 (unsigned long) len,
328 (unsigned long) wpabuf_tailroom(data->in_buf));
329 }
330
331 return 0;
332 }
333
334
eap_ikev2_server_keymat(struct eap_ikev2_data * data)335 static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
336 {
337 if (eap_ikev2_derive_keymat(
338 data->ikev2.proposal.prf, &data->ikev2.keys,
339 data->ikev2.i_nonce, data->ikev2.i_nonce_len,
340 data->ikev2.r_nonce, data->ikev2.r_nonce_len,
341 data->keymat) < 0) {
342 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
343 "key material");
344 return -1;
345 }
346 data->keymat_ok = 1;
347 return 0;
348 }
349
350
eap_ikev2_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)351 static void eap_ikev2_process(struct eap_sm *sm, void *priv,
352 struct wpabuf *respData)
353 {
354 struct eap_ikev2_data *data = priv;
355 const u8 *start, *pos, *end;
356 size_t len;
357 u8 flags;
358 u32 message_length = 0;
359 struct wpabuf tmpbuf;
360
361 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
362 &len);
363 if (pos == NULL)
364 return; /* Should not happen; message already verified */
365
366 start = pos;
367 end = start + len;
368
369 if (len == 0) {
370 /* fragment ack */
371 flags = 0;
372 } else
373 flags = *pos++;
374
375 if (eap_ikev2_process_icv(data, respData, flags, pos, &end,
376 data->state == WAIT_FRAG_ACK && len == 0) < 0)
377 {
378 eap_ikev2_state(data, FAIL);
379 return;
380 }
381
382 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
383 if (end - pos < 4) {
384 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
385 eap_ikev2_state(data, FAIL);
386 return;
387 }
388 message_length = WPA_GET_BE32(pos);
389 pos += 4;
390
391 if (message_length < (u32) (end - pos)) {
392 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
393 "Length (%d; %ld remaining in this msg)",
394 message_length, (long) (end - pos));
395 eap_ikev2_state(data, FAIL);
396 return;
397 }
398 }
399 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
400 "Message Length %u", flags, message_length);
401
402 if (data->state == WAIT_FRAG_ACK) {
403 if (len != 0) {
404 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
405 "in WAIT_FRAG_ACK state");
406 eap_ikev2_state(data, FAIL);
407 return;
408 }
409 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
410 eap_ikev2_state(data, MSG);
411 return;
412 }
413
414 if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
415 eap_ikev2_state(data, FAIL);
416 return;
417 }
418
419 if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
420 if (eap_ikev2_process_fragment(data, flags, message_length,
421 pos, end - pos) < 0)
422 eap_ikev2_state(data, FAIL);
423 else
424 eap_ikev2_state(data, FRAG_ACK);
425 return;
426 } else if (data->state == FRAG_ACK) {
427 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
428 data->state = MSG;
429 }
430
431 if (data->in_buf == NULL) {
432 /* Wrap unfragmented messages as wpabuf without extra copy */
433 wpabuf_set(&tmpbuf, pos, end - pos);
434 data->in_buf = &tmpbuf;
435 }
436
437 if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
438 if (data->in_buf == &tmpbuf)
439 data->in_buf = NULL;
440 eap_ikev2_state(data, FAIL);
441 return;
442 }
443
444 switch (data->ikev2.state) {
445 case SA_AUTH:
446 /* SA_INIT was sent out, so message have to be
447 * integrity protected from now on. */
448 data->keys_ready = 1;
449 break;
450 case IKEV2_DONE:
451 if (data->state == FAIL)
452 break;
453 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
454 "successfully");
455 if (eap_ikev2_server_keymat(data))
456 break;
457 eap_ikev2_state(data, DONE);
458 break;
459 default:
460 break;
461 }
462
463 if (data->in_buf != &tmpbuf)
464 wpabuf_free(data->in_buf);
465 data->in_buf = NULL;
466 }
467
468
eap_ikev2_isDone(struct eap_sm * sm,void * priv)469 static Boolean eap_ikev2_isDone(struct eap_sm *sm, void *priv)
470 {
471 struct eap_ikev2_data *data = priv;
472 return data->state == DONE || data->state == FAIL;
473 }
474
475
eap_ikev2_isSuccess(struct eap_sm * sm,void * priv)476 static Boolean eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
477 {
478 struct eap_ikev2_data *data = priv;
479 return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
480 data->keymat_ok;
481 }
482
483
eap_ikev2_getKey(struct eap_sm * sm,void * priv,size_t * len)484 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
485 {
486 struct eap_ikev2_data *data = priv;
487 u8 *key;
488
489 if (data->state != DONE || !data->keymat_ok)
490 return NULL;
491
492 key = os_malloc(EAP_MSK_LEN);
493 if (key) {
494 os_memcpy(key, data->keymat, EAP_MSK_LEN);
495 *len = EAP_MSK_LEN;
496 }
497
498 return key;
499 }
500
501
eap_ikev2_get_emsk(struct eap_sm * sm,void * priv,size_t * len)502 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
503 {
504 struct eap_ikev2_data *data = priv;
505 u8 *key;
506
507 if (data->state != DONE || !data->keymat_ok)
508 return NULL;
509
510 key = os_malloc(EAP_EMSK_LEN);
511 if (key) {
512 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
513 *len = EAP_EMSK_LEN;
514 }
515
516 return key;
517 }
518
519
eap_ikev2_get_session_id(struct eap_sm * sm,void * priv,size_t * len)520 static u8 * eap_ikev2_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
521 {
522 struct eap_ikev2_data *data = priv;
523 u8 *sid;
524 size_t sid_len;
525 size_t offset;
526
527 if (data->state != DONE || !data->keymat_ok)
528 return NULL;
529
530 sid_len = 1 + data->ikev2.i_nonce_len + data->ikev2.r_nonce_len;
531 sid = os_malloc(sid_len);
532 if (sid) {
533 offset = 0;
534 sid[offset] = EAP_TYPE_IKEV2;
535 offset++;
536 os_memcpy(sid + offset, data->ikev2.i_nonce,
537 data->ikev2.i_nonce_len);
538 offset += data->ikev2.i_nonce_len;
539 os_memcpy(sid + offset, data->ikev2.r_nonce,
540 data->ikev2.r_nonce_len);
541 *len = sid_len;
542 wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Derived Session-Id",
543 sid, sid_len);
544 }
545
546 return sid;
547 }
548
549
eap_server_ikev2_register(void)550 int eap_server_ikev2_register(void)
551 {
552 struct eap_method *eap;
553
554 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
555 EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
556 "IKEV2");
557 if (eap == NULL)
558 return -1;
559
560 eap->init = eap_ikev2_init;
561 eap->reset = eap_ikev2_reset;
562 eap->buildReq = eap_ikev2_buildReq;
563 eap->check = eap_ikev2_check;
564 eap->process = eap_ikev2_process;
565 eap->isDone = eap_ikev2_isDone;
566 eap->getKey = eap_ikev2_getKey;
567 eap->isSuccess = eap_ikev2_isSuccess;
568 eap->get_emsk = eap_ikev2_get_emsk;
569 eap->getSessionId = eap_ikev2_get_session_id;
570
571 return eap_server_method_register(eap);
572 }
573