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->cfg->fragment_size > 0 ?
91 sm->cfg->fragment_size : 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_memdup(sm->cfg->server_id, sm->cfg->server_id_len);
107 if (data->ikev2.IDi == NULL)
108 goto failed;
109 data->ikev2.IDi_len = sm->cfg->server_id_len;
110
111 data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
112 data->ikev2.cb_ctx = sm;
113
114 return data;
115
116 failed:
117 ikev2_initiator_deinit(&data->ikev2);
118 os_free(data);
119 return NULL;
120 }
121
122
eap_ikev2_reset(struct eap_sm * sm,void * priv)123 static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
124 {
125 struct eap_ikev2_data *data = priv;
126 wpabuf_free(data->in_buf);
127 wpabuf_free(data->out_buf);
128 ikev2_initiator_deinit(&data->ikev2);
129 bin_clear_free(data, sizeof(*data));
130 }
131
132
eap_ikev2_build_msg(struct eap_ikev2_data * data,u8 id)133 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
134 {
135 struct wpabuf *req;
136 u8 flags;
137 size_t send_len, plen, icv_len = 0;
138
139 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
140
141 flags = 0;
142 send_len = wpabuf_len(data->out_buf) - data->out_used;
143 if (1 + send_len > data->fragment_size) {
144 send_len = data->fragment_size - 1;
145 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
146 if (data->out_used == 0) {
147 flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
148 send_len -= 4;
149 }
150 }
151
152 plen = 1 + send_len;
153 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
154 plen += 4;
155 if (data->keys_ready) {
156 const struct ikev2_integ_alg *integ;
157 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
158 "Data");
159 flags |= IKEV2_FLAGS_ICV_INCLUDED;
160 integ = ikev2_get_integ(data->ikev2.proposal.integ);
161 if (integ == NULL) {
162 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
163 "transform / cannot generate ICV");
164 return NULL;
165 }
166 icv_len = integ->hash_len;
167
168 plen += icv_len;
169 }
170 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
171 EAP_CODE_REQUEST, id);
172 if (req == NULL)
173 return NULL;
174
175 wpabuf_put_u8(req, flags); /* Flags */
176 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
177 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
178
179 wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
180 send_len);
181 data->out_used += send_len;
182
183 if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
184 const u8 *msg = wpabuf_head(req);
185 size_t len = wpabuf_len(req);
186 ikev2_integ_hash(data->ikev2.proposal.integ,
187 data->ikev2.keys.SK_ai,
188 data->ikev2.keys.SK_integ_len,
189 msg, len, wpabuf_put(req, icv_len));
190 }
191
192 if (data->out_used == wpabuf_len(data->out_buf)) {
193 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
194 "(message sent completely)",
195 (unsigned long) send_len);
196 wpabuf_free(data->out_buf);
197 data->out_buf = NULL;
198 data->out_used = 0;
199 } else {
200 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
201 "(%lu more to send)", (unsigned long) send_len,
202 (unsigned long) wpabuf_len(data->out_buf) -
203 data->out_used);
204 eap_ikev2_state(data, WAIT_FRAG_ACK);
205 }
206
207 return req;
208 }
209
210
eap_ikev2_buildReq(struct eap_sm * sm,void * priv,u8 id)211 static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
212 {
213 struct eap_ikev2_data *data = priv;
214
215 switch (data->state) {
216 case MSG:
217 if (data->out_buf == NULL) {
218 data->out_buf = ikev2_initiator_build(&data->ikev2);
219 if (data->out_buf == NULL) {
220 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
221 "generate IKEv2 message");
222 return NULL;
223 }
224 data->out_used = 0;
225 }
226 /* fall through */
227 case WAIT_FRAG_ACK:
228 return eap_ikev2_build_msg(data, id);
229 case FRAG_ACK:
230 return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
231 default:
232 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
233 "buildReq", data->state);
234 return NULL;
235 }
236 }
237
238
eap_ikev2_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)239 static bool eap_ikev2_check(struct eap_sm *sm, void *priv,
240 struct wpabuf *respData)
241 {
242 const u8 *pos;
243 size_t len;
244
245 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
246 &len);
247 if (pos == NULL) {
248 wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
249 return true;
250 }
251
252 return false;
253 }
254
255
eap_ikev2_process_icv(struct eap_ikev2_data * data,const struct wpabuf * respData,u8 flags,const u8 * pos,const u8 ** end,int frag_ack)256 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
257 const struct wpabuf *respData,
258 u8 flags, const u8 *pos, const u8 **end,
259 int frag_ack)
260 {
261 if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
262 int icv_len = eap_ikev2_validate_icv(
263 data->ikev2.proposal.integ, &data->ikev2.keys, 0,
264 respData, pos, *end);
265 if (icv_len < 0)
266 return -1;
267 /* Hide Integrity Checksum Data from further processing */
268 *end -= icv_len;
269 } else if (data->keys_ready && !frag_ack) {
270 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
271 "included integrity checksum");
272 return -1;
273 }
274
275 return 0;
276 }
277
278
eap_ikev2_process_cont(struct eap_ikev2_data * data,const u8 * buf,size_t len)279 static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
280 const u8 *buf, size_t len)
281 {
282 /* Process continuation of a pending message */
283 if (len > wpabuf_tailroom(data->in_buf)) {
284 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
285 eap_ikev2_state(data, FAIL);
286 return -1;
287 }
288
289 wpabuf_put_data(data->in_buf, buf, len);
290 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
291 "bytes more", (unsigned long) len,
292 (unsigned long) wpabuf_tailroom(data->in_buf));
293
294 return 0;
295 }
296
297
eap_ikev2_process_fragment(struct eap_ikev2_data * data,u8 flags,u32 message_length,const u8 * buf,size_t len)298 static int eap_ikev2_process_fragment(struct eap_ikev2_data *data,
299 u8 flags, u32 message_length,
300 const u8 *buf, size_t len)
301 {
302 /* Process a fragment that is not the last one of the message */
303 if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
304 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
305 "a fragmented packet");
306 return -1;
307 }
308
309 if (data->in_buf == NULL) {
310 /* First fragment of the message */
311 if (message_length > 50000) {
312 /* Limit maximum memory allocation */
313 wpa_printf(MSG_DEBUG,
314 "EAP-IKEV2: Ignore too long message");
315 return -1;
316 }
317 data->in_buf = wpabuf_alloc(message_length);
318 if (data->in_buf == NULL) {
319 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
320 "message");
321 return -1;
322 }
323 wpabuf_put_data(data->in_buf, buf, len);
324 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
325 "fragment, waiting for %lu bytes more",
326 (unsigned long) len,
327 (unsigned long) wpabuf_tailroom(data->in_buf));
328 }
329
330 return 0;
331 }
332
333
eap_ikev2_server_keymat(struct eap_ikev2_data * data)334 static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
335 {
336 if (eap_ikev2_derive_keymat(
337 data->ikev2.proposal.prf, &data->ikev2.keys,
338 data->ikev2.i_nonce, data->ikev2.i_nonce_len,
339 data->ikev2.r_nonce, data->ikev2.r_nonce_len,
340 data->keymat) < 0) {
341 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
342 "key material");
343 return -1;
344 }
345 data->keymat_ok = 1;
346 return 0;
347 }
348
349
eap_ikev2_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)350 static void eap_ikev2_process(struct eap_sm *sm, void *priv,
351 struct wpabuf *respData)
352 {
353 struct eap_ikev2_data *data = priv;
354 const u8 *start, *pos, *end;
355 size_t len;
356 u8 flags;
357 u32 message_length = 0;
358 struct wpabuf tmpbuf;
359
360 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
361 &len);
362 if (pos == NULL)
363 return; /* Should not happen; message already verified */
364
365 start = pos;
366 end = start + len;
367
368 if (len == 0) {
369 /* fragment ack */
370 flags = 0;
371 } else
372 flags = *pos++;
373
374 if (eap_ikev2_process_icv(data, respData, flags, pos, &end,
375 data->state == WAIT_FRAG_ACK && len == 0) < 0)
376 {
377 eap_ikev2_state(data, FAIL);
378 return;
379 }
380
381 if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
382 if (end - pos < 4) {
383 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
384 eap_ikev2_state(data, FAIL);
385 return;
386 }
387 message_length = WPA_GET_BE32(pos);
388 pos += 4;
389
390 if (message_length < (u32) (end - pos)) {
391 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
392 "Length (%d; %ld remaining in this msg)",
393 message_length, (long) (end - pos));
394 eap_ikev2_state(data, FAIL);
395 return;
396 }
397 }
398 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
399 "Message Length %u", flags, message_length);
400
401 if (data->state == WAIT_FRAG_ACK) {
402 if (len != 0) {
403 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
404 "in WAIT_FRAG_ACK state");
405 eap_ikev2_state(data, FAIL);
406 return;
407 }
408 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
409 eap_ikev2_state(data, MSG);
410 return;
411 }
412
413 if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
414 eap_ikev2_state(data, FAIL);
415 return;
416 }
417
418 if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
419 if (eap_ikev2_process_fragment(data, flags, message_length,
420 pos, end - pos) < 0)
421 eap_ikev2_state(data, FAIL);
422 else
423 eap_ikev2_state(data, FRAG_ACK);
424 return;
425 } else if (data->state == FRAG_ACK) {
426 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
427 data->state = MSG;
428 }
429
430 if (data->in_buf == NULL) {
431 /* Wrap unfragmented messages as wpabuf without extra copy */
432 wpabuf_set(&tmpbuf, pos, end - pos);
433 data->in_buf = &tmpbuf;
434 }
435
436 if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
437 if (data->in_buf == &tmpbuf)
438 data->in_buf = NULL;
439 eap_ikev2_state(data, FAIL);
440 return;
441 }
442
443 switch (data->ikev2.state) {
444 case SA_AUTH:
445 /* SA_INIT was sent out, so message have to be
446 * integrity protected from now on. */
447 data->keys_ready = 1;
448 break;
449 case IKEV2_DONE:
450 if (data->state == FAIL)
451 break;
452 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
453 "successfully");
454 if (eap_ikev2_server_keymat(data))
455 break;
456 eap_ikev2_state(data, DONE);
457 break;
458 default:
459 break;
460 }
461
462 if (data->in_buf != &tmpbuf)
463 wpabuf_free(data->in_buf);
464 data->in_buf = NULL;
465 }
466
467
eap_ikev2_isDone(struct eap_sm * sm,void * priv)468 static bool eap_ikev2_isDone(struct eap_sm *sm, void *priv)
469 {
470 struct eap_ikev2_data *data = priv;
471 return data->state == DONE || data->state == FAIL;
472 }
473
474
eap_ikev2_isSuccess(struct eap_sm * sm,void * priv)475 static bool eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
476 {
477 struct eap_ikev2_data *data = priv;
478 return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
479 data->keymat_ok;
480 }
481
482
eap_ikev2_getKey(struct eap_sm * sm,void * priv,size_t * len)483 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
484 {
485 struct eap_ikev2_data *data = priv;
486 u8 *key;
487
488 if (data->state != DONE || !data->keymat_ok)
489 return NULL;
490
491 key = os_malloc(EAP_MSK_LEN);
492 if (key) {
493 os_memcpy(key, data->keymat, EAP_MSK_LEN);
494 *len = EAP_MSK_LEN;
495 }
496
497 return key;
498 }
499
500
eap_ikev2_get_emsk(struct eap_sm * sm,void * priv,size_t * len)501 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
502 {
503 struct eap_ikev2_data *data = priv;
504 u8 *key;
505
506 if (data->state != DONE || !data->keymat_ok)
507 return NULL;
508
509 key = os_malloc(EAP_EMSK_LEN);
510 if (key) {
511 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
512 *len = EAP_EMSK_LEN;
513 }
514
515 return key;
516 }
517
518
eap_ikev2_get_session_id(struct eap_sm * sm,void * priv,size_t * len)519 static u8 * eap_ikev2_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
520 {
521 struct eap_ikev2_data *data = priv;
522 u8 *sid;
523 size_t sid_len;
524 size_t offset;
525
526 if (data->state != DONE || !data->keymat_ok)
527 return NULL;
528
529 sid_len = 1 + data->ikev2.i_nonce_len + data->ikev2.r_nonce_len;
530 sid = os_malloc(sid_len);
531 if (sid) {
532 offset = 0;
533 sid[offset] = EAP_TYPE_IKEV2;
534 offset++;
535 os_memcpy(sid + offset, data->ikev2.i_nonce,
536 data->ikev2.i_nonce_len);
537 offset += data->ikev2.i_nonce_len;
538 os_memcpy(sid + offset, data->ikev2.r_nonce,
539 data->ikev2.r_nonce_len);
540 *len = sid_len;
541 wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Derived Session-Id",
542 sid, sid_len);
543 }
544
545 return sid;
546 }
547
548
eap_server_ikev2_register(void)549 int eap_server_ikev2_register(void)
550 {
551 struct eap_method *eap;
552
553 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
554 EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
555 "IKEV2");
556 if (eap == NULL)
557 return -1;
558
559 eap->init = eap_ikev2_init;
560 eap->reset = eap_ikev2_reset;
561 eap->buildReq = eap_ikev2_buildReq;
562 eap->check = eap_ikev2_check;
563 eap->process = eap_ikev2_process;
564 eap->isDone = eap_ikev2_isDone;
565 eap->getKey = eap_ikev2_getKey;
566 eap->isSuccess = eap_ikev2_isSuccess;
567 eap->get_emsk = eap_ikev2_get_emsk;
568 eap->getSessionId = eap_ikev2_get_session_id;
569
570 return eap_server_method_register(eap);
571 }
572