1 /*
2 * EAP-TLS/PEAP/TTLS/FAST server common functions
3 * Copyright (c) 2004-2009, 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 "crypto/sha1.h"
13 #include "crypto/tls.h"
14 #include "eap_i.h"
15 #include "eap_tls_common.h"
16
17
18 static void eap_server_tls_free_in_buf(struct eap_ssl_data *data);
19
20
eap_tls_msg_alloc(EapType type,size_t payload_len,u8 code,u8 identifier)21 struct wpabuf * eap_tls_msg_alloc(EapType type, size_t payload_len,
22 u8 code, u8 identifier)
23 {
24 if (type == EAP_UNAUTH_TLS_TYPE)
25 return eap_msg_alloc(EAP_VENDOR_UNAUTH_TLS,
26 EAP_VENDOR_TYPE_UNAUTH_TLS, payload_len,
27 code, identifier);
28 else if (type == EAP_WFA_UNAUTH_TLS_TYPE)
29 return eap_msg_alloc(EAP_VENDOR_WFA_NEW,
30 EAP_VENDOR_WFA_UNAUTH_TLS, payload_len,
31 code, identifier);
32 return eap_msg_alloc(EAP_VENDOR_IETF, type, payload_len, code,
33 identifier);
34 }
35
36
37 #ifdef CONFIG_TLS_INTERNAL
eap_server_tls_log_cb(void * ctx,const char * msg)38 static void eap_server_tls_log_cb(void *ctx, const char *msg)
39 {
40 struct eap_sm *sm = ctx;
41 eap_log_msg(sm, "TLS: %s", msg);
42 }
43 #endif /* CONFIG_TLS_INTERNAL */
44
45
eap_server_tls_ssl_init(struct eap_sm * sm,struct eap_ssl_data * data,int verify_peer,int eap_type)46 int eap_server_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
47 int verify_peer, int eap_type)
48 {
49 u8 session_ctx[8];
50 unsigned int flags = sm->tls_flags;
51
52 if (sm->ssl_ctx == NULL) {
53 wpa_printf(MSG_ERROR, "TLS context not initialized - cannot use TLS-based EAP method");
54 return -1;
55 }
56
57 data->eap = sm;
58 data->phase2 = sm->init_phase2;
59
60 data->conn = tls_connection_init(sm->ssl_ctx);
61 if (data->conn == NULL) {
62 wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS "
63 "connection");
64 return -1;
65 }
66
67 #ifdef CONFIG_TLS_INTERNAL
68 tls_connection_set_log_cb(data->conn, eap_server_tls_log_cb, sm);
69 #ifdef CONFIG_TESTING_OPTIONS
70 tls_connection_set_test_flags(data->conn, sm->tls_test_flags);
71 #endif /* CONFIG_TESTING_OPTIONS */
72 #endif /* CONFIG_TLS_INTERNAL */
73
74 if (eap_type != EAP_TYPE_FAST)
75 flags |= TLS_CONN_DISABLE_SESSION_TICKET;
76 os_memcpy(session_ctx, "hostapd", 7);
77 session_ctx[7] = (u8) eap_type;
78 if (tls_connection_set_verify(sm->ssl_ctx, data->conn, verify_peer,
79 flags, session_ctx,
80 sizeof(session_ctx))) {
81 wpa_printf(MSG_INFO, "SSL: Failed to configure verification "
82 "of TLS peer certificate");
83 tls_connection_deinit(sm->ssl_ctx, data->conn);
84 data->conn = NULL;
85 return -1;
86 }
87
88 data->tls_out_limit = sm->fragment_size > 0 ? sm->fragment_size : 1398;
89 if (data->phase2) {
90 /* Limit the fragment size in the inner TLS authentication
91 * since the outer authentication with EAP-PEAP does not yet
92 * support fragmentation */
93 if (data->tls_out_limit > 100)
94 data->tls_out_limit -= 100;
95 }
96 return 0;
97 }
98
99
eap_server_tls_ssl_deinit(struct eap_sm * sm,struct eap_ssl_data * data)100 void eap_server_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data)
101 {
102 tls_connection_deinit(sm->ssl_ctx, data->conn);
103 eap_server_tls_free_in_buf(data);
104 wpabuf_free(data->tls_out);
105 data->tls_out = NULL;
106 }
107
108
eap_server_tls_derive_key(struct eap_sm * sm,struct eap_ssl_data * data,char * label,size_t len)109 u8 * eap_server_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
110 char *label, size_t len)
111 {
112 u8 *out;
113
114 out = os_malloc(len);
115 if (out == NULL)
116 return NULL;
117
118 if (tls_connection_export_key(sm->ssl_ctx, data->conn, label, out,
119 len)) {
120 os_free(out);
121 return NULL;
122 }
123
124 return out;
125 }
126
127
128 /**
129 * eap_server_tls_derive_session_id - Derive a Session-Id based on TLS data
130 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
131 * @data: Data for TLS processing
132 * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST)
133 * @len: Pointer to length of the session ID generated
134 * Returns: Pointer to allocated Session-Id on success or %NULL on failure
135 *
136 * This function derive the Session-Id based on the TLS session data
137 * (client/server random and method type).
138 *
139 * The caller is responsible for freeing the returned buffer.
140 */
eap_server_tls_derive_session_id(struct eap_sm * sm,struct eap_ssl_data * data,u8 eap_type,size_t * len)141 u8 * eap_server_tls_derive_session_id(struct eap_sm *sm,
142 struct eap_ssl_data *data, u8 eap_type,
143 size_t *len)
144 {
145 struct tls_random keys;
146 u8 *out;
147
148 if (tls_connection_get_random(sm->ssl_ctx, data->conn, &keys))
149 return NULL;
150
151 if (keys.client_random == NULL || keys.server_random == NULL)
152 return NULL;
153
154 *len = 1 + keys.client_random_len + keys.server_random_len;
155 out = os_malloc(*len);
156 if (out == NULL)
157 return NULL;
158
159 /* Session-Id = EAP type || client.random || server.random */
160 out[0] = eap_type;
161 os_memcpy(out + 1, keys.client_random, keys.client_random_len);
162 os_memcpy(out + 1 + keys.client_random_len, keys.server_random,
163 keys.server_random_len);
164
165 return out;
166 }
167
168
eap_server_tls_build_msg(struct eap_ssl_data * data,int eap_type,int version,u8 id)169 struct wpabuf * eap_server_tls_build_msg(struct eap_ssl_data *data,
170 int eap_type, int version, u8 id)
171 {
172 struct wpabuf *req;
173 u8 flags;
174 size_t send_len, plen;
175
176 wpa_printf(MSG_DEBUG, "SSL: Generating Request");
177 if (data->tls_out == NULL) {
178 wpa_printf(MSG_ERROR, "SSL: tls_out NULL in %s", __func__);
179 return NULL;
180 }
181
182 flags = version;
183 send_len = wpabuf_len(data->tls_out) - data->tls_out_pos;
184 if (1 + send_len > data->tls_out_limit) {
185 send_len = data->tls_out_limit - 1;
186 flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
187 if (data->tls_out_pos == 0) {
188 flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
189 send_len -= 4;
190 }
191 }
192
193 plen = 1 + send_len;
194 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)
195 plen += 4;
196
197 req = eap_tls_msg_alloc(eap_type, plen, EAP_CODE_REQUEST, id);
198 if (req == NULL)
199 return NULL;
200
201 wpabuf_put_u8(req, flags); /* Flags */
202 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)
203 wpabuf_put_be32(req, wpabuf_len(data->tls_out));
204
205 wpabuf_put_data(req, wpabuf_head_u8(data->tls_out) + data->tls_out_pos,
206 send_len);
207 data->tls_out_pos += send_len;
208
209 if (data->tls_out_pos == wpabuf_len(data->tls_out)) {
210 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes "
211 "(message sent completely)",
212 (unsigned long) send_len);
213 wpabuf_free(data->tls_out);
214 data->tls_out = NULL;
215 data->tls_out_pos = 0;
216 data->state = MSG;
217 } else {
218 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes "
219 "(%lu more to send)", (unsigned long) send_len,
220 (unsigned long) wpabuf_len(data->tls_out) -
221 data->tls_out_pos);
222 data->state = WAIT_FRAG_ACK;
223 }
224
225 return req;
226 }
227
228
eap_server_tls_build_ack(u8 id,int eap_type,int version)229 struct wpabuf * eap_server_tls_build_ack(u8 id, int eap_type, int version)
230 {
231 struct wpabuf *req;
232
233 req = eap_tls_msg_alloc(eap_type, 1, EAP_CODE_REQUEST, id);
234 if (req == NULL)
235 return NULL;
236 wpa_printf(MSG_DEBUG, "SSL: Building ACK");
237 wpabuf_put_u8(req, version); /* Flags */
238 return req;
239 }
240
241
eap_server_tls_process_cont(struct eap_ssl_data * data,const u8 * buf,size_t len)242 static int eap_server_tls_process_cont(struct eap_ssl_data *data,
243 const u8 *buf, size_t len)
244 {
245 /* Process continuation of a pending message */
246 if (len > wpabuf_tailroom(data->tls_in)) {
247 wpa_printf(MSG_DEBUG, "SSL: Fragment overflow");
248 return -1;
249 }
250
251 wpabuf_put_data(data->tls_in, buf, len);
252 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes, waiting for %lu "
253 "bytes more", (unsigned long) len,
254 (unsigned long) wpabuf_tailroom(data->tls_in));
255
256 return 0;
257 }
258
259
eap_server_tls_process_fragment(struct eap_ssl_data * data,u8 flags,u32 message_length,const u8 * buf,size_t len)260 static int eap_server_tls_process_fragment(struct eap_ssl_data *data,
261 u8 flags, u32 message_length,
262 const u8 *buf, size_t len)
263 {
264 /* Process a fragment that is not the last one of the message */
265 if (data->tls_in == NULL && !(flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)) {
266 wpa_printf(MSG_DEBUG, "SSL: No Message Length field in a "
267 "fragmented packet");
268 return -1;
269 }
270
271 if (data->tls_in == NULL) {
272 /* First fragment of the message */
273
274 /* Limit length to avoid rogue peers from causing large
275 * memory allocations. */
276 if (message_length > 65536) {
277 wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size"
278 " over 64 kB)");
279 return -1;
280 }
281
282 if (len > message_length) {
283 wpa_printf(MSG_INFO, "SSL: Too much data (%d bytes) in "
284 "first fragment of frame (TLS Message "
285 "Length %d bytes)",
286 (int) len, (int) message_length);
287 return -1;
288 }
289
290 data->tls_in = wpabuf_alloc(message_length);
291 if (data->tls_in == NULL) {
292 wpa_printf(MSG_DEBUG, "SSL: No memory for message");
293 return -1;
294 }
295 wpabuf_put_data(data->tls_in, buf, len);
296 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes in first "
297 "fragment, waiting for %lu bytes more",
298 (unsigned long) len,
299 (unsigned long) wpabuf_tailroom(data->tls_in));
300 }
301
302 return 0;
303 }
304
305
eap_server_tls_phase1(struct eap_sm * sm,struct eap_ssl_data * data)306 int eap_server_tls_phase1(struct eap_sm *sm, struct eap_ssl_data *data)
307 {
308 if (data->tls_out) {
309 /* This should not happen.. */
310 wpa_printf(MSG_INFO, "SSL: pending tls_out data when "
311 "processing new message");
312 wpabuf_free(data->tls_out);
313 WPA_ASSERT(data->tls_out == NULL);
314 }
315
316 data->tls_out = tls_connection_server_handshake(sm->ssl_ctx,
317 data->conn,
318 data->tls_in, NULL);
319 if (data->tls_out == NULL) {
320 wpa_printf(MSG_INFO, "SSL: TLS processing failed");
321 return -1;
322 }
323 if (tls_connection_get_failed(sm->ssl_ctx, data->conn)) {
324 /* TLS processing has failed - return error */
325 wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
326 "report error");
327 return -1;
328 }
329
330 return 0;
331 }
332
333
eap_server_tls_reassemble(struct eap_ssl_data * data,u8 flags,const u8 ** pos,size_t * left)334 static int eap_server_tls_reassemble(struct eap_ssl_data *data, u8 flags,
335 const u8 **pos, size_t *left)
336 {
337 unsigned int tls_msg_len = 0;
338 const u8 *end = *pos + *left;
339
340 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
341 if (*left < 4) {
342 wpa_printf(MSG_INFO, "SSL: Short frame with TLS "
343 "length");
344 return -1;
345 }
346 tls_msg_len = WPA_GET_BE32(*pos);
347 wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d",
348 tls_msg_len);
349 *pos += 4;
350 *left -= 4;
351
352 if (*left > tls_msg_len) {
353 wpa_printf(MSG_INFO, "SSL: TLS Message Length (%d "
354 "bytes) smaller than this fragment (%d "
355 "bytes)", (int) tls_msg_len, (int) *left);
356 return -1;
357 }
358 }
359
360 wpa_printf(MSG_DEBUG, "SSL: Received packet: Flags 0x%x "
361 "Message Length %u", flags, tls_msg_len);
362
363 if (data->state == WAIT_FRAG_ACK) {
364 if (*left != 0) {
365 wpa_printf(MSG_DEBUG, "SSL: Unexpected payload in "
366 "WAIT_FRAG_ACK state");
367 return -1;
368 }
369 wpa_printf(MSG_DEBUG, "SSL: Fragment acknowledged");
370 return 1;
371 }
372
373 if (data->tls_in &&
374 eap_server_tls_process_cont(data, *pos, end - *pos) < 0)
375 return -1;
376
377 if (flags & EAP_TLS_FLAGS_MORE_FRAGMENTS) {
378 if (eap_server_tls_process_fragment(data, flags, tls_msg_len,
379 *pos, end - *pos) < 0)
380 return -1;
381
382 data->state = FRAG_ACK;
383 return 1;
384 }
385
386 if (data->state == FRAG_ACK) {
387 wpa_printf(MSG_DEBUG, "SSL: All fragments received");
388 data->state = MSG;
389 }
390
391 if (data->tls_in == NULL) {
392 /* Wrap unfragmented messages as wpabuf without extra copy */
393 wpabuf_set(&data->tmpbuf, *pos, end - *pos);
394 data->tls_in = &data->tmpbuf;
395 }
396
397 return 0;
398 }
399
400
eap_server_tls_free_in_buf(struct eap_ssl_data * data)401 static void eap_server_tls_free_in_buf(struct eap_ssl_data *data)
402 {
403 if (data->tls_in != &data->tmpbuf)
404 wpabuf_free(data->tls_in);
405 data->tls_in = NULL;
406 }
407
408
eap_server_tls_encrypt(struct eap_sm * sm,struct eap_ssl_data * data,const struct wpabuf * plain)409 struct wpabuf * eap_server_tls_encrypt(struct eap_sm *sm,
410 struct eap_ssl_data *data,
411 const struct wpabuf *plain)
412 {
413 struct wpabuf *buf;
414
415 buf = tls_connection_encrypt(sm->ssl_ctx, data->conn,
416 plain);
417 if (buf == NULL) {
418 wpa_printf(MSG_INFO, "SSL: Failed to encrypt Phase 2 data");
419 return NULL;
420 }
421
422 return buf;
423 }
424
425
eap_server_tls_process(struct eap_sm * sm,struct eap_ssl_data * data,struct wpabuf * respData,void * priv,int eap_type,int (* proc_version)(struct eap_sm * sm,void * priv,int peer_version),void (* proc_msg)(struct eap_sm * sm,void * priv,const struct wpabuf * respData))426 int eap_server_tls_process(struct eap_sm *sm, struct eap_ssl_data *data,
427 struct wpabuf *respData, void *priv, int eap_type,
428 int (*proc_version)(struct eap_sm *sm, void *priv,
429 int peer_version),
430 void (*proc_msg)(struct eap_sm *sm, void *priv,
431 const struct wpabuf *respData))
432 {
433 const u8 *pos;
434 u8 flags;
435 size_t left;
436 int ret, res = 0;
437
438 if (eap_type == EAP_UNAUTH_TLS_TYPE)
439 pos = eap_hdr_validate(EAP_VENDOR_UNAUTH_TLS,
440 EAP_VENDOR_TYPE_UNAUTH_TLS, respData,
441 &left);
442 else if (eap_type == EAP_WFA_UNAUTH_TLS_TYPE)
443 pos = eap_hdr_validate(EAP_VENDOR_WFA_NEW,
444 EAP_VENDOR_WFA_UNAUTH_TLS, respData,
445 &left);
446 else
447 pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, respData,
448 &left);
449 if (pos == NULL || left < 1)
450 return 0; /* Should not happen - frame already validated */
451 flags = *pos++;
452 left--;
453 wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - Flags 0x%02x",
454 (unsigned long) wpabuf_len(respData), flags);
455
456 if (proc_version &&
457 proc_version(sm, priv, flags & EAP_TLS_VERSION_MASK) < 0)
458 return -1;
459
460 ret = eap_server_tls_reassemble(data, flags, &pos, &left);
461 if (ret < 0) {
462 res = -1;
463 goto done;
464 } else if (ret == 1)
465 return 0;
466
467 if (proc_msg)
468 proc_msg(sm, priv, respData);
469
470 if (tls_connection_get_write_alerts(sm->ssl_ctx, data->conn) > 1) {
471 wpa_printf(MSG_INFO, "SSL: Locally detected fatal error in "
472 "TLS processing");
473 res = -1;
474 }
475
476 done:
477 eap_server_tls_free_in_buf(data);
478
479 return res;
480 }
481