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,const char * label,const u8 * context,size_t context_len,size_t len)109 u8 * eap_server_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
110 const char *label, const u8 *context,
111 size_t context_len, size_t len)
112 {
113 u8 *out;
114
115 out = os_malloc(len);
116 if (out == NULL)
117 return NULL;
118
119 if (tls_connection_export_key(sm->ssl_ctx, data->conn, label,
120 context, context_len, out, len)) {
121 os_free(out);
122 return NULL;
123 }
124
125 return out;
126 }
127
128
129 /**
130 * eap_server_tls_derive_session_id - Derive a Session-Id based on TLS data
131 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
132 * @data: Data for TLS processing
133 * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST)
134 * @len: Pointer to length of the session ID generated
135 * Returns: Pointer to allocated Session-Id on success or %NULL on failure
136 *
137 * This function derive the Session-Id based on the TLS session data
138 * (client/server random and method type).
139 *
140 * The caller is responsible for freeing the returned buffer.
141 */
eap_server_tls_derive_session_id(struct eap_sm * sm,struct eap_ssl_data * data,u8 eap_type,size_t * len)142 u8 * eap_server_tls_derive_session_id(struct eap_sm *sm,
143 struct eap_ssl_data *data, u8 eap_type,
144 size_t *len)
145 {
146 struct tls_random keys;
147 u8 *out;
148 const u8 context[] = { EAP_TYPE_TLS };
149
150 if (eap_type == EAP_TYPE_TLS && data->tls_v13) {
151 u8 *id, *method_id;
152
153 /* Session-Id = <EAP-Type> || Method-Id
154 * Method-Id = TLS-Exporter("EXPORTER_EAP_TLS_Method-Id",
155 * Type-Code, 64)
156 */
157 *len = 1 + 64;
158 id = os_malloc(*len);
159 if (!id)
160 return NULL;
161 method_id = eap_server_tls_derive_key(
162 sm, data, "EXPORTER_EAP_TLS_Method-Id", context, 1, 64);
163 if (!method_id) {
164 os_free(id);
165 return NULL;
166 }
167 id[0] = eap_type;
168 os_memcpy(id + 1, method_id, 64);
169 os_free(method_id);
170 return id;
171 }
172
173 if (tls_connection_get_random(sm->ssl_ctx, data->conn, &keys))
174 return NULL;
175
176 if (keys.client_random == NULL || keys.server_random == NULL)
177 return NULL;
178
179 *len = 1 + keys.client_random_len + keys.server_random_len;
180 out = os_malloc(*len);
181 if (out == NULL)
182 return NULL;
183
184 /* Session-Id = EAP type || client.random || server.random */
185 out[0] = eap_type;
186 os_memcpy(out + 1, keys.client_random, keys.client_random_len);
187 os_memcpy(out + 1 + keys.client_random_len, keys.server_random,
188 keys.server_random_len);
189
190 return out;
191 }
192
193
eap_server_tls_build_msg(struct eap_ssl_data * data,int eap_type,int version,u8 id)194 struct wpabuf * eap_server_tls_build_msg(struct eap_ssl_data *data,
195 int eap_type, int version, u8 id)
196 {
197 struct wpabuf *req;
198 u8 flags;
199 size_t send_len, plen;
200
201 wpa_printf(MSG_DEBUG, "SSL: Generating Request");
202 if (data->tls_out == NULL) {
203 wpa_printf(MSG_ERROR, "SSL: tls_out NULL in %s", __func__);
204 return NULL;
205 }
206
207 flags = version;
208 send_len = wpabuf_len(data->tls_out) - data->tls_out_pos;
209 if (1 + send_len > data->tls_out_limit) {
210 send_len = data->tls_out_limit - 1;
211 flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
212 if (data->tls_out_pos == 0) {
213 flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
214 send_len -= 4;
215 }
216 }
217
218 plen = 1 + send_len;
219 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)
220 plen += 4;
221
222 req = eap_tls_msg_alloc(eap_type, plen, EAP_CODE_REQUEST, id);
223 if (req == NULL)
224 return NULL;
225
226 wpabuf_put_u8(req, flags); /* Flags */
227 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)
228 wpabuf_put_be32(req, wpabuf_len(data->tls_out));
229
230 wpabuf_put_data(req, wpabuf_head_u8(data->tls_out) + data->tls_out_pos,
231 send_len);
232 data->tls_out_pos += send_len;
233
234 if (data->tls_out_pos == wpabuf_len(data->tls_out)) {
235 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes "
236 "(message sent completely)",
237 (unsigned long) send_len);
238 wpabuf_free(data->tls_out);
239 data->tls_out = NULL;
240 data->tls_out_pos = 0;
241 data->state = MSG;
242 } else {
243 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes "
244 "(%lu more to send)", (unsigned long) send_len,
245 (unsigned long) wpabuf_len(data->tls_out) -
246 data->tls_out_pos);
247 data->state = WAIT_FRAG_ACK;
248 }
249
250 return req;
251 }
252
253
eap_server_tls_build_ack(u8 id,int eap_type,int version)254 struct wpabuf * eap_server_tls_build_ack(u8 id, int eap_type, int version)
255 {
256 struct wpabuf *req;
257
258 req = eap_tls_msg_alloc(eap_type, 1, EAP_CODE_REQUEST, id);
259 if (req == NULL)
260 return NULL;
261 wpa_printf(MSG_DEBUG, "SSL: Building ACK");
262 wpabuf_put_u8(req, version); /* Flags */
263 return req;
264 }
265
266
eap_server_tls_process_cont(struct eap_ssl_data * data,const u8 * buf,size_t len)267 static int eap_server_tls_process_cont(struct eap_ssl_data *data,
268 const u8 *buf, size_t len)
269 {
270 /* Process continuation of a pending message */
271 if (len > wpabuf_tailroom(data->tls_in)) {
272 wpa_printf(MSG_DEBUG, "SSL: Fragment overflow");
273 return -1;
274 }
275
276 wpabuf_put_data(data->tls_in, buf, len);
277 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes, waiting for %lu "
278 "bytes more", (unsigned long) len,
279 (unsigned long) wpabuf_tailroom(data->tls_in));
280
281 return 0;
282 }
283
284
eap_server_tls_process_fragment(struct eap_ssl_data * data,u8 flags,u32 message_length,const u8 * buf,size_t len)285 static int eap_server_tls_process_fragment(struct eap_ssl_data *data,
286 u8 flags, u32 message_length,
287 const u8 *buf, size_t len)
288 {
289 /* Process a fragment that is not the last one of the message */
290 if (data->tls_in == NULL && !(flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)) {
291 wpa_printf(MSG_DEBUG, "SSL: No Message Length field in a "
292 "fragmented packet");
293 return -1;
294 }
295
296 if (data->tls_in == NULL) {
297 /* First fragment of the message */
298
299 /* Limit length to avoid rogue peers from causing large
300 * memory allocations. */
301 if (message_length > 65536) {
302 wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size"
303 " over 64 kB)");
304 return -1;
305 }
306
307 if (len > message_length) {
308 wpa_printf(MSG_INFO, "SSL: Too much data (%d bytes) in "
309 "first fragment of frame (TLS Message "
310 "Length %d bytes)",
311 (int) len, (int) message_length);
312 return -1;
313 }
314
315 data->tls_in = wpabuf_alloc(message_length);
316 if (data->tls_in == NULL) {
317 wpa_printf(MSG_DEBUG, "SSL: No memory for message");
318 return -1;
319 }
320 wpabuf_put_data(data->tls_in, buf, len);
321 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes in first "
322 "fragment, waiting for %lu bytes more",
323 (unsigned long) len,
324 (unsigned long) wpabuf_tailroom(data->tls_in));
325 }
326
327 return 0;
328 }
329
330
eap_server_tls_phase1(struct eap_sm * sm,struct eap_ssl_data * data)331 int eap_server_tls_phase1(struct eap_sm *sm, struct eap_ssl_data *data)
332 {
333 char buf[20];
334
335 if (data->tls_out) {
336 /* This should not happen.. */
337 wpa_printf(MSG_INFO, "SSL: pending tls_out data when "
338 "processing new message");
339 wpabuf_free(data->tls_out);
340 WPA_ASSERT(data->tls_out == NULL);
341 }
342
343 data->tls_out = tls_connection_server_handshake(sm->ssl_ctx,
344 data->conn,
345 data->tls_in, NULL);
346 if (data->tls_out == NULL) {
347 wpa_printf(MSG_INFO, "SSL: TLS processing failed");
348 return -1;
349 }
350 if (tls_connection_get_failed(sm->ssl_ctx, data->conn)) {
351 /* TLS processing has failed - return error */
352 wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
353 "report error");
354 return -1;
355 }
356
357 if (tls_get_version(sm->ssl_ctx, data->conn, buf, sizeof(buf)) == 0) {
358 wpa_printf(MSG_DEBUG, "SSL: Using TLS version %s", buf);
359 data->tls_v13 = os_strcmp(buf, "TLSv1.3") == 0;
360 }
361
362 if (!sm->serial_num &&
363 tls_connection_established(sm->ssl_ctx, data->conn))
364 sm->serial_num = tls_connection_peer_serial_num(sm->ssl_ctx,
365 data->conn);
366
367 return 0;
368 }
369
370
eap_server_tls_reassemble(struct eap_ssl_data * data,u8 flags,const u8 ** pos,size_t * left)371 static int eap_server_tls_reassemble(struct eap_ssl_data *data, u8 flags,
372 const u8 **pos, size_t *left)
373 {
374 unsigned int tls_msg_len = 0;
375 const u8 *end = *pos + *left;
376
377 wpa_hexdump(MSG_MSGDUMP, "SSL: Received data", *pos, *left);
378
379 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
380 if (*left < 4) {
381 wpa_printf(MSG_INFO, "SSL: Short frame with TLS "
382 "length");
383 return -1;
384 }
385 tls_msg_len = WPA_GET_BE32(*pos);
386 wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d",
387 tls_msg_len);
388 *pos += 4;
389 *left -= 4;
390
391 if (*left > tls_msg_len) {
392 wpa_printf(MSG_INFO, "SSL: TLS Message Length (%d "
393 "bytes) smaller than this fragment (%d "
394 "bytes)", (int) tls_msg_len, (int) *left);
395 return -1;
396 }
397 }
398
399 wpa_printf(MSG_DEBUG, "SSL: Received packet: Flags 0x%x "
400 "Message Length %u", flags, tls_msg_len);
401
402 if (data->state == WAIT_FRAG_ACK) {
403 if (*left != 0) {
404 wpa_printf(MSG_DEBUG, "SSL: Unexpected payload in "
405 "WAIT_FRAG_ACK state");
406 return -1;
407 }
408 wpa_printf(MSG_DEBUG, "SSL: Fragment acknowledged");
409 return 1;
410 }
411
412 if (data->tls_in &&
413 eap_server_tls_process_cont(data, *pos, end - *pos) < 0)
414 return -1;
415
416 if (flags & EAP_TLS_FLAGS_MORE_FRAGMENTS) {
417 if (eap_server_tls_process_fragment(data, flags, tls_msg_len,
418 *pos, end - *pos) < 0)
419 return -1;
420
421 data->state = FRAG_ACK;
422 return 1;
423 }
424
425 if (data->state == FRAG_ACK) {
426 wpa_printf(MSG_DEBUG, "SSL: All fragments received");
427 data->state = MSG;
428 }
429
430 if (data->tls_in == NULL) {
431 /* Wrap unfragmented messages as wpabuf without extra copy */
432 wpabuf_set(&data->tmpbuf, *pos, end - *pos);
433 data->tls_in = &data->tmpbuf;
434 }
435
436 return 0;
437 }
438
439
eap_server_tls_free_in_buf(struct eap_ssl_data * data)440 static void eap_server_tls_free_in_buf(struct eap_ssl_data *data)
441 {
442 if (data->tls_in != &data->tmpbuf)
443 wpabuf_free(data->tls_in);
444 data->tls_in = NULL;
445 }
446
447
eap_server_tls_encrypt(struct eap_sm * sm,struct eap_ssl_data * data,const struct wpabuf * plain)448 struct wpabuf * eap_server_tls_encrypt(struct eap_sm *sm,
449 struct eap_ssl_data *data,
450 const struct wpabuf *plain)
451 {
452 struct wpabuf *buf;
453
454 buf = tls_connection_encrypt(sm->ssl_ctx, data->conn,
455 plain);
456 if (buf == NULL) {
457 wpa_printf(MSG_INFO, "SSL: Failed to encrypt Phase 2 data");
458 return NULL;
459 }
460
461 return buf;
462 }
463
464
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))465 int eap_server_tls_process(struct eap_sm *sm, struct eap_ssl_data *data,
466 struct wpabuf *respData, void *priv, int eap_type,
467 int (*proc_version)(struct eap_sm *sm, void *priv,
468 int peer_version),
469 void (*proc_msg)(struct eap_sm *sm, void *priv,
470 const struct wpabuf *respData))
471 {
472 const u8 *pos;
473 u8 flags;
474 size_t left;
475 int ret, res = 0;
476
477 if (eap_type == EAP_UNAUTH_TLS_TYPE)
478 pos = eap_hdr_validate(EAP_VENDOR_UNAUTH_TLS,
479 EAP_VENDOR_TYPE_UNAUTH_TLS, respData,
480 &left);
481 else if (eap_type == EAP_WFA_UNAUTH_TLS_TYPE)
482 pos = eap_hdr_validate(EAP_VENDOR_WFA_NEW,
483 EAP_VENDOR_WFA_UNAUTH_TLS, respData,
484 &left);
485 else
486 pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, respData,
487 &left);
488 if (pos == NULL || left < 1)
489 return 0; /* Should not happen - frame already validated */
490 flags = *pos++;
491 left--;
492 wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - Flags 0x%02x",
493 (unsigned long) wpabuf_len(respData), flags);
494
495 if (proc_version &&
496 proc_version(sm, priv, flags & EAP_TLS_VERSION_MASK) < 0)
497 return -1;
498
499 ret = eap_server_tls_reassemble(data, flags, &pos, &left);
500 if (ret < 0) {
501 res = -1;
502 goto done;
503 } else if (ret == 1)
504 return 0;
505
506 if (proc_msg)
507 proc_msg(sm, priv, respData);
508
509 if (tls_connection_get_write_alerts(sm->ssl_ctx, data->conn) > 1) {
510 wpa_printf(MSG_INFO, "SSL: Locally detected fatal error in "
511 "TLS processing");
512 res = -1;
513 }
514
515 done:
516 eap_server_tls_free_in_buf(data);
517
518 return res;
519 }
520