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1 /*
2  * TLSv1 server - write handshake message
3  * Copyright (c) 2006-2014, 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/md5.h"
13 #include "crypto/sha1.h"
14 #include "crypto/sha256.h"
15 #include "crypto/tls.h"
16 #include "crypto/random.h"
17 #include "x509v3.h"
18 #include "tlsv1_common.h"
19 #include "tlsv1_record.h"
20 #include "tlsv1_server.h"
21 #include "tlsv1_server_i.h"
22 
23 
tls_server_cert_chain_der_len(struct tlsv1_server * conn)24 static size_t tls_server_cert_chain_der_len(struct tlsv1_server *conn)
25 {
26 	size_t len = 0;
27 	struct x509_certificate *cert;
28 
29 	cert = conn->cred ? conn->cred->cert : NULL;
30 	while (cert) {
31 		len += 3 + cert->cert_len;
32 		if (x509_certificate_self_signed(cert))
33 			break;
34 		cert = x509_certificate_get_subject(conn->cred->trusted_certs,
35 						    &cert->issuer);
36 	}
37 
38 	return len;
39 }
40 
41 
tls_write_server_hello(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)42 static int tls_write_server_hello(struct tlsv1_server *conn,
43 				  u8 **msgpos, u8 *end)
44 {
45 	u8 *pos, *rhdr, *hs_start, *hs_length, *ext_start;
46 	struct os_time now;
47 	size_t rlen;
48 
49 	pos = *msgpos;
50 
51 	tlsv1_server_log(conn, "Send ServerHello");
52 	rhdr = pos;
53 	pos += TLS_RECORD_HEADER_LEN;
54 
55 	os_get_time(&now);
56 #ifdef TEST_FUZZ
57 	now.sec = 0xfffefdfc;
58 #endif /* TEST_FUZZ */
59 	WPA_PUT_BE32(conn->server_random, now.sec);
60 	if (random_get_bytes(conn->server_random + 4, TLS_RANDOM_LEN - 4)) {
61 		wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
62 			   "server_random");
63 		return -1;
64 	}
65 	wpa_hexdump(MSG_MSGDUMP, "TLSv1: server_random",
66 		    conn->server_random, TLS_RANDOM_LEN);
67 
68 	conn->session_id_len = TLS_SESSION_ID_MAX_LEN;
69 	if (random_get_bytes(conn->session_id, conn->session_id_len)) {
70 		wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
71 			   "session_id");
72 		return -1;
73 	}
74 	wpa_hexdump(MSG_MSGDUMP, "TLSv1: session_id",
75 		    conn->session_id, conn->session_id_len);
76 
77 	/* opaque fragment[TLSPlaintext.length] */
78 
79 	/* Handshake */
80 	hs_start = pos;
81 	/* HandshakeType msg_type */
82 	*pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO;
83 	/* uint24 length (to be filled) */
84 	hs_length = pos;
85 	pos += 3;
86 	/* body - ServerHello */
87 	/* ProtocolVersion server_version */
88 	WPA_PUT_BE16(pos, conn->rl.tls_version);
89 	pos += 2;
90 	/* Random random: uint32 gmt_unix_time, opaque random_bytes */
91 	os_memcpy(pos, conn->server_random, TLS_RANDOM_LEN);
92 	pos += TLS_RANDOM_LEN;
93 	/* SessionID session_id */
94 	*pos++ = conn->session_id_len;
95 	os_memcpy(pos, conn->session_id, conn->session_id_len);
96 	pos += conn->session_id_len;
97 	/* CipherSuite cipher_suite */
98 	WPA_PUT_BE16(pos, conn->cipher_suite);
99 	pos += 2;
100 	/* CompressionMethod compression_method */
101 	*pos++ = TLS_COMPRESSION_NULL;
102 
103 	/* Extension */
104 	ext_start = pos;
105 	pos += 2;
106 
107 	if (conn->status_request) {
108 		/* Add a status_request extension with empty extension_data */
109 		/* ExtensionsType extension_type = status_request(5) */
110 		WPA_PUT_BE16(pos, TLS_EXT_STATUS_REQUEST);
111 		pos += 2;
112 		/* opaque extension_data<0..2^16-1> length */
113 		WPA_PUT_BE16(pos, 0);
114 		pos += 2;
115 	}
116 
117 	if (conn->status_request_v2) {
118 		/*
119 		  Add a status_request_v2 extension with empty extension_data
120 		*/
121 		/* ExtensionsType extension_type = status_request_v2(17) */
122 		WPA_PUT_BE16(pos, TLS_EXT_STATUS_REQUEST_V2);
123 		pos += 2;
124 		/* opaque extension_data<0..2^16-1> length */
125 		WPA_PUT_BE16(pos, 0);
126 		pos += 2;
127 	}
128 
129 	if (conn->session_ticket && conn->session_ticket_cb) {
130 		int res = conn->session_ticket_cb(
131 			conn->session_ticket_cb_ctx,
132 			conn->session_ticket, conn->session_ticket_len,
133 			conn->client_random, conn->server_random,
134 			conn->master_secret);
135 		if (res < 0) {
136 			tlsv1_server_log(conn, "SessionTicket callback indicated failure");
137 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
138 					   TLS_ALERT_HANDSHAKE_FAILURE);
139 			return -1;
140 		}
141 		conn->use_session_ticket = res;
142 
143 		if (conn->use_session_ticket) {
144 			if (tlsv1_server_derive_keys(conn, NULL, 0) < 0) {
145 				wpa_printf(MSG_DEBUG, "TLSv1: Failed to "
146 					   "derive keys");
147 				tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
148 						   TLS_ALERT_INTERNAL_ERROR);
149 				return -1;
150 			}
151 		}
152 
153 		/*
154 		 * RFC 4507 specifies that server would include an empty
155 		 * SessionTicket extension in ServerHello and a
156 		 * NewSessionTicket message after the ServerHello. However,
157 		 * EAP-FAST (RFC 4851), i.e., the only user of SessionTicket
158 		 * extension at the moment, does not use such extensions.
159 		 *
160 		 * TODO: Add support for configuring RFC 4507 behavior and make
161 		 * EAP-FAST disable it.
162 		 */
163 	}
164 
165 	if (pos == ext_start + 2)
166 		pos -= 2; /* no extensions */
167 	else
168 		WPA_PUT_BE16(ext_start, pos - ext_start - 2);
169 
170 	WPA_PUT_BE24(hs_length, pos - hs_length - 3);
171 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
172 
173 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
174 			      rhdr, end - rhdr, hs_start, pos - hs_start,
175 			      &rlen) < 0) {
176 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to create TLS record");
177 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
178 				   TLS_ALERT_INTERNAL_ERROR);
179 		return -1;
180 	}
181 	pos = rhdr + rlen;
182 
183 	*msgpos = pos;
184 
185 	return 0;
186 }
187 
188 
tls_write_server_certificate(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)189 static int tls_write_server_certificate(struct tlsv1_server *conn,
190 					u8 **msgpos, u8 *end)
191 {
192 	u8 *pos, *rhdr, *hs_start, *hs_length, *cert_start;
193 	size_t rlen;
194 	struct x509_certificate *cert;
195 	const struct tls_cipher_suite *suite;
196 
197 	suite = tls_get_cipher_suite(conn->rl.cipher_suite);
198 	if (suite && suite->key_exchange == TLS_KEY_X_DH_anon) {
199 		wpa_printf(MSG_DEBUG, "TLSv1: Do not send Certificate when "
200 			   "using anonymous DH");
201 		return 0;
202 	}
203 
204 	pos = *msgpos;
205 	if (TLS_RECORD_HEADER_LEN + 1 + 3 + 3 > end - pos) {
206 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
207 				   TLS_ALERT_INTERNAL_ERROR);
208 		return -1;
209 	}
210 
211 	tlsv1_server_log(conn, "Send Certificate");
212 	rhdr = pos;
213 	pos += TLS_RECORD_HEADER_LEN;
214 
215 	/* opaque fragment[TLSPlaintext.length] */
216 
217 	/* Handshake */
218 	hs_start = pos;
219 	/* HandshakeType msg_type */
220 	*pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE;
221 	/* uint24 length (to be filled) */
222 	hs_length = pos;
223 	pos += 3;
224 	/* body - Certificate */
225 	/* uint24 length (to be filled) */
226 	cert_start = pos;
227 	pos += 3;
228 	cert = conn->cred->cert;
229 	while (cert) {
230 		if (3 + cert->cert_len > (size_t) (end - pos)) {
231 			wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space "
232 				   "for Certificate (cert_len=%lu left=%lu)",
233 				   (unsigned long) cert->cert_len,
234 				   (unsigned long) (end - pos));
235 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
236 					   TLS_ALERT_INTERNAL_ERROR);
237 			return -1;
238 		}
239 		WPA_PUT_BE24(pos, cert->cert_len);
240 		pos += 3;
241 		os_memcpy(pos, cert->cert_start, cert->cert_len);
242 		pos += cert->cert_len;
243 
244 		if (x509_certificate_self_signed(cert))
245 			break;
246 		cert = x509_certificate_get_subject(conn->cred->trusted_certs,
247 						    &cert->issuer);
248 	}
249 	if (cert == conn->cred->cert || cert == NULL) {
250 		/*
251 		 * Server was not configured with all the needed certificates
252 		 * to form a full certificate chain. The client may fail to
253 		 * validate the chain unless it is configured with all the
254 		 * missing CA certificates.
255 		 */
256 		wpa_printf(MSG_DEBUG, "TLSv1: Full server certificate chain "
257 			   "not configured - validation may fail");
258 	}
259 	WPA_PUT_BE24(cert_start, pos - cert_start - 3);
260 
261 	WPA_PUT_BE24(hs_length, pos - hs_length - 3);
262 
263 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
264 			      rhdr, end - rhdr, hs_start, pos - hs_start,
265 			      &rlen) < 0) {
266 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
267 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
268 				   TLS_ALERT_INTERNAL_ERROR);
269 		return -1;
270 	}
271 	pos = rhdr + rlen;
272 
273 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
274 
275 	*msgpos = pos;
276 
277 	return 0;
278 }
279 
280 
tls_write_server_certificate_status(struct tlsv1_server * conn,u8 ** msgpos,u8 * end,int ocsp_multi,char * ocsp_resp,size_t ocsp_resp_len)281 static int tls_write_server_certificate_status(struct tlsv1_server *conn,
282 					       u8 **msgpos, u8 *end,
283 					       int ocsp_multi,
284 					       char *ocsp_resp,
285 					       size_t ocsp_resp_len)
286 {
287 	u8 *pos, *rhdr, *hs_start, *hs_length;
288 	size_t rlen;
289 
290 	if (!ocsp_resp) {
291 		 /*
292 		  * Client did not request certificate status or there is no
293 		  * matching response cached.
294 		  */
295 		return 0;
296 	}
297 
298 	pos = *msgpos;
299 	if (TLS_RECORD_HEADER_LEN + 1 + 3 + 1 + 3 + ocsp_resp_len >
300 	    (unsigned int) (end - pos)) {
301 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
302 				   TLS_ALERT_INTERNAL_ERROR);
303 		return -1;
304 	}
305 
306 	tlsv1_server_log(conn, "Send CertificateStatus (multi=%d)", ocsp_multi);
307 	rhdr = pos;
308 	pos += TLS_RECORD_HEADER_LEN;
309 
310 	/* opaque fragment[TLSPlaintext.length] */
311 
312 	/* Handshake */
313 	hs_start = pos;
314 	/* HandshakeType msg_type */
315 	*pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE_STATUS;
316 	/* uint24 length (to be filled) */
317 	hs_length = pos;
318 	pos += 3;
319 
320 	/* body - CertificateStatus
321 	 *
322 	 * struct {
323 	 *     CertificateStatusType status_type;
324 	 *     select (status_type) {
325 	 *         case ocsp: OCSPResponse;
326 	 *         case ocsp_multi: OCSPResponseList;
327 	 *     } response;
328 	 * } CertificateStatus;
329 	 *
330 	 * opaque OCSPResponse<1..2^24-1>;
331 	 *
332 	 * struct {
333 	 *   OCSPResponse ocsp_response_list<1..2^24-1>;
334 	 * } OCSPResponseList;
335 	 */
336 
337 	/* CertificateStatusType status_type */
338 	if (ocsp_multi)
339 		*pos++ = 2; /* ocsp_multi(2) */
340 	else
341 		*pos++ = 1; /* ocsp(1) */
342 	/* uint24 length of OCSPResponse */
343 	WPA_PUT_BE24(pos, ocsp_resp_len);
344 	pos += 3;
345 	os_memcpy(pos, ocsp_resp, ocsp_resp_len);
346 	pos += ocsp_resp_len;
347 
348 	WPA_PUT_BE24(hs_length, pos - hs_length - 3);
349 
350 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
351 			      rhdr, end - rhdr, hs_start, pos - hs_start,
352 			      &rlen) < 0) {
353 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
354 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
355 				   TLS_ALERT_INTERNAL_ERROR);
356 		return -1;
357 	}
358 	pos = rhdr + rlen;
359 
360 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
361 
362 	*msgpos = pos;
363 
364 	return 0;
365 }
366 
367 
tls_write_server_key_exchange(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)368 static int tls_write_server_key_exchange(struct tlsv1_server *conn,
369 					 u8 **msgpos, u8 *end)
370 {
371 	tls_key_exchange keyx;
372 	const struct tls_cipher_suite *suite;
373 	u8 *pos, *rhdr, *hs_start, *hs_length, *server_params;
374 	size_t rlen;
375 	u8 *dh_ys;
376 	size_t dh_ys_len;
377 	const u8 *dh_p;
378 	size_t dh_p_len;
379 
380 	suite = tls_get_cipher_suite(conn->rl.cipher_suite);
381 	if (suite == NULL)
382 		keyx = TLS_KEY_X_NULL;
383 	else
384 		keyx = suite->key_exchange;
385 
386 	if (!tls_server_key_exchange_allowed(conn->rl.cipher_suite)) {
387 		wpa_printf(MSG_DEBUG, "TLSv1: No ServerKeyExchange needed");
388 		return 0;
389 	}
390 
391 	if (keyx != TLS_KEY_X_DH_anon && keyx != TLS_KEY_X_DHE_RSA) {
392 		wpa_printf(MSG_DEBUG, "TLSv1: ServerKeyExchange not yet "
393 			   "supported with key exchange type %d", keyx);
394 		return -1;
395 	}
396 
397 	if (conn->cred == NULL || conn->cred->dh_p == NULL ||
398 	    conn->cred->dh_g == NULL) {
399 		wpa_printf(MSG_DEBUG, "TLSv1: No DH parameters available for "
400 			   "ServerKeyExhcange");
401 		return -1;
402 	}
403 
404 	tlsv1_server_get_dh_p(conn, &dh_p, &dh_p_len);
405 
406 	os_free(conn->dh_secret);
407 	conn->dh_secret_len = dh_p_len;
408 	conn->dh_secret = os_malloc(conn->dh_secret_len);
409 	if (conn->dh_secret == NULL) {
410 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate "
411 			   "memory for secret (Diffie-Hellman)");
412 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
413 				   TLS_ALERT_INTERNAL_ERROR);
414 		return -1;
415 	}
416 	if (random_get_bytes(conn->dh_secret, conn->dh_secret_len)) {
417 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to get random "
418 			   "data for Diffie-Hellman");
419 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
420 				   TLS_ALERT_INTERNAL_ERROR);
421 		os_free(conn->dh_secret);
422 		conn->dh_secret = NULL;
423 		return -1;
424 	}
425 
426 	if (os_memcmp(conn->dh_secret, dh_p, conn->dh_secret_len) > 0)
427 		conn->dh_secret[0] = 0; /* make sure secret < p */
428 
429 	pos = conn->dh_secret;
430 	while (pos + 1 < conn->dh_secret + conn->dh_secret_len && *pos == 0)
431 		pos++;
432 	if (pos != conn->dh_secret) {
433 		os_memmove(conn->dh_secret, pos,
434 			   conn->dh_secret_len - (pos - conn->dh_secret));
435 		conn->dh_secret_len -= pos - conn->dh_secret;
436 	}
437 	wpa_hexdump_key(MSG_DEBUG, "TLSv1: DH server's secret value",
438 			conn->dh_secret, conn->dh_secret_len);
439 
440 	/* Ys = g^secret mod p */
441 	dh_ys_len = dh_p_len;
442 	dh_ys = os_malloc(dh_ys_len);
443 	if (dh_ys == NULL) {
444 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate memory for "
445 			   "Diffie-Hellman");
446 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
447 				   TLS_ALERT_INTERNAL_ERROR);
448 		return -1;
449 	}
450 	if (crypto_mod_exp(conn->cred->dh_g, conn->cred->dh_g_len,
451 			   conn->dh_secret, conn->dh_secret_len,
452 			   dh_p, dh_p_len, dh_ys, &dh_ys_len)) {
453 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
454 				   TLS_ALERT_INTERNAL_ERROR);
455 		os_free(dh_ys);
456 		return -1;
457 	}
458 
459 	wpa_hexdump(MSG_DEBUG, "TLSv1: DH Ys (server's public value)",
460 		    dh_ys, dh_ys_len);
461 
462 	/*
463 	 * struct {
464 	 *    select (KeyExchangeAlgorithm) {
465 	 *       case diffie_hellman:
466 	 *          ServerDHParams params;
467 	 *          Signature signed_params;
468 	 *       case rsa:
469 	 *          ServerRSAParams params;
470 	 *          Signature signed_params;
471 	 *    };
472 	 * } ServerKeyExchange;
473 	 *
474 	 * struct {
475 	 *    opaque dh_p<1..2^16-1>;
476 	 *    opaque dh_g<1..2^16-1>;
477 	 *    opaque dh_Ys<1..2^16-1>;
478 	 * } ServerDHParams;
479 	 */
480 
481 	pos = *msgpos;
482 
483 	tlsv1_server_log(conn, "Send ServerKeyExchange");
484 	rhdr = pos;
485 	pos += TLS_RECORD_HEADER_LEN;
486 
487 	/* opaque fragment[TLSPlaintext.length] */
488 
489 	/* Handshake */
490 	hs_start = pos;
491 	/* HandshakeType msg_type */
492 	*pos++ = TLS_HANDSHAKE_TYPE_SERVER_KEY_EXCHANGE;
493 	/* uint24 length (to be filled) */
494 	hs_length = pos;
495 	pos += 3;
496 
497 	/* body - ServerDHParams */
498 	server_params = pos;
499 	/* dh_p */
500 	if (2 + dh_p_len > (size_t) (end - pos)) {
501 		wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
502 			   "dh_p");
503 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
504 				   TLS_ALERT_INTERNAL_ERROR);
505 		os_free(dh_ys);
506 		return -1;
507 	}
508 	WPA_PUT_BE16(pos, dh_p_len);
509 	pos += 2;
510 	os_memcpy(pos, dh_p, dh_p_len);
511 	pos += dh_p_len;
512 
513 	/* dh_g */
514 	if (2 + conn->cred->dh_g_len > (size_t) (end - pos)) {
515 		wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
516 			   "dh_g");
517 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
518 				   TLS_ALERT_INTERNAL_ERROR);
519 		os_free(dh_ys);
520 		return -1;
521 	}
522 	WPA_PUT_BE16(pos, conn->cred->dh_g_len);
523 	pos += 2;
524 	os_memcpy(pos, conn->cred->dh_g, conn->cred->dh_g_len);
525 	pos += conn->cred->dh_g_len;
526 
527 	/* dh_Ys */
528 	if (2 + dh_ys_len > (size_t) (end - pos)) {
529 		wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
530 			   "dh_Ys");
531 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
532 				   TLS_ALERT_INTERNAL_ERROR);
533 		os_free(dh_ys);
534 		return -1;
535 	}
536 	WPA_PUT_BE16(pos, dh_ys_len);
537 	pos += 2;
538 	os_memcpy(pos, dh_ys, dh_ys_len);
539 	pos += dh_ys_len;
540 	os_free(dh_ys);
541 
542 	/*
543 	 * select (SignatureAlgorithm)
544 	 * {   case anonymous: struct { };
545 	 *     case rsa:
546 	 *         digitally-signed struct {
547 	 *             opaque md5_hash[16];
548 	 *             opaque sha_hash[20];
549 	 *         };
550 	 *     case dsa:
551 	 *         digitally-signed struct {
552 	 *             opaque sha_hash[20];
553 	 *         };
554 	 * } Signature;
555 	 *
556 	 * md5_hash
557 	 *     MD5(ClientHello.random + ServerHello.random + ServerParams);
558 	 *
559 	 * sha_hash
560 	 *     SHA(ClientHello.random + ServerHello.random + ServerParams);
561 	 */
562 
563 	if (keyx == TLS_KEY_X_DHE_RSA) {
564 		u8 hash[100];
565 		u8 *signed_start;
566 		size_t clen;
567 		int hlen;
568 
569 		if (conn->rl.tls_version >= TLS_VERSION_1_2) {
570 #ifdef CONFIG_TLSV12
571 			hlen = tlsv12_key_x_server_params_hash(
572 				conn->rl.tls_version, TLS_HASH_ALG_SHA256,
573 				conn->client_random,
574 				conn->server_random, server_params,
575 				pos - server_params, hash + 19);
576 
577 			/*
578 			 * RFC 5246, 4.7:
579 			 * TLS v1.2 adds explicit indication of the used
580 			 * signature and hash algorithms.
581 			 *
582 			 * struct {
583 			 *   HashAlgorithm hash;
584 			 *   SignatureAlgorithm signature;
585 			 * } SignatureAndHashAlgorithm;
586 			 */
587 			if (hlen < 0 || end - pos < 2) {
588 				tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
589 						   TLS_ALERT_INTERNAL_ERROR);
590 				return -1;
591 			}
592 			*pos++ = TLS_HASH_ALG_SHA256;
593 			*pos++ = TLS_SIGN_ALG_RSA;
594 
595 			/*
596 			 * RFC 3447, A.2.4 RSASSA-PKCS1-v1_5
597 			 *
598 			 * DigestInfo ::= SEQUENCE {
599 			 *   digestAlgorithm DigestAlgorithm,
600 			 *   digest OCTET STRING
601 			 * }
602 			 *
603 			 * SHA-256 OID: sha256WithRSAEncryption ::= {pkcs-1 11}
604 			 *
605 			 * DER encoded DigestInfo for SHA256 per RFC 3447:
606 			 * 30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00
607 			 * 04 20 || H
608 			 */
609 			hlen += 19;
610 			os_memcpy(hash,
611 				  "\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65"
612 				  "\x03\x04\x02\x01\x05\x00\x04\x20", 19);
613 
614 #else /* CONFIG_TLSV12 */
615 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
616 					   TLS_ALERT_INTERNAL_ERROR);
617 			return -1;
618 #endif /* CONFIG_TLSV12 */
619 		} else {
620 			hlen = tls_key_x_server_params_hash(
621 				conn->rl.tls_version, conn->client_random,
622 				conn->server_random, server_params,
623 				pos - server_params, hash);
624 		}
625 
626 		if (hlen < 0) {
627 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
628 					   TLS_ALERT_INTERNAL_ERROR);
629 			return -1;
630 		}
631 
632 		wpa_hexdump(MSG_MSGDUMP, "TLS: ServerKeyExchange signed_params hash",
633 			    hash, hlen);
634 #ifdef CONFIG_TESTING_OPTIONS
635 		if (conn->test_flags & TLS_BREAK_SRV_KEY_X_HASH) {
636 			tlsv1_server_log(conn, "TESTING: Break ServerKeyExchange signed params hash");
637 			hash[hlen - 1] ^= 0x80;
638 		}
639 #endif /* CONFIG_TESTING_OPTIONS */
640 
641 		/*
642 		 * RFC 2246, 4.7:
643 		 * In digital signing, one-way hash functions are used as input
644 		 * for a signing algorithm. A digitally-signed element is
645 		 * encoded as an opaque vector <0..2^16-1>, where the length is
646 		 * specified by the signing algorithm and key.
647 		 *
648 		 * In RSA signing, a 36-byte structure of two hashes (one SHA
649 		 * and one MD5) is signed (encrypted with the private key). It
650 		 * is encoded with PKCS #1 block type 0 or type 1 as described
651 		 * in [PKCS1].
652 		 */
653 		signed_start = pos; /* length to be filled */
654 		pos += 2;
655 		clen = end - pos;
656 		if (conn->cred == NULL ||
657 		    crypto_private_key_sign_pkcs1(conn->cred->key, hash, hlen,
658 						  pos, &clen) < 0) {
659 			wpa_printf(MSG_DEBUG, "TLSv1: Failed to sign hash (PKCS #1)");
660 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
661 					   TLS_ALERT_INTERNAL_ERROR);
662 			return -1;
663 		}
664 		WPA_PUT_BE16(signed_start, clen);
665 #ifdef CONFIG_TESTING_OPTIONS
666 		if (conn->test_flags & TLS_BREAK_SRV_KEY_X_SIGNATURE) {
667 			tlsv1_server_log(conn, "TESTING: Break ServerKeyExchange signed params signature");
668 			pos[clen - 1] ^= 0x80;
669 		}
670 #endif /* CONFIG_TESTING_OPTIONS */
671 
672 		pos += clen;
673 	}
674 
675 	WPA_PUT_BE24(hs_length, pos - hs_length - 3);
676 
677 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
678 			      rhdr, end - rhdr, hs_start, pos - hs_start,
679 			      &rlen) < 0) {
680 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
681 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
682 				   TLS_ALERT_INTERNAL_ERROR);
683 		return -1;
684 	}
685 	pos = rhdr + rlen;
686 
687 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
688 
689 	*msgpos = pos;
690 
691 	return 0;
692 }
693 
694 
tls_write_server_certificate_request(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)695 static int tls_write_server_certificate_request(struct tlsv1_server *conn,
696 						u8 **msgpos, u8 *end)
697 {
698 	u8 *pos, *rhdr, *hs_start, *hs_length;
699 	size_t rlen;
700 
701 	if (!conn->verify_peer) {
702 		wpa_printf(MSG_DEBUG, "TLSv1: No CertificateRequest needed");
703 		return 0;
704 	}
705 
706 	pos = *msgpos;
707 
708 	tlsv1_server_log(conn, "Send CertificateRequest");
709 	rhdr = pos;
710 	pos += TLS_RECORD_HEADER_LEN;
711 
712 	/* opaque fragment[TLSPlaintext.length] */
713 
714 	/* Handshake */
715 	hs_start = pos;
716 	/* HandshakeType msg_type */
717 	*pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE_REQUEST;
718 	/* uint24 length (to be filled) */
719 	hs_length = pos;
720 	pos += 3;
721 	/* body - CertificateRequest */
722 
723 	/*
724 	 * enum {
725 	 *   rsa_sign(1), dss_sign(2), rsa_fixed_dh(3), dss_fixed_dh(4),
726 	 *   (255)
727 	 * } ClientCertificateType;
728 	 * ClientCertificateType certificate_types<1..2^8-1>
729 	 */
730 	*pos++ = 1;
731 	*pos++ = 1; /* rsa_sign */
732 
733 	/*
734 	 * opaque DistinguishedName<1..2^16-1>
735 	 * DistinguishedName certificate_authorities<3..2^16-1>
736 	 */
737 	/* TODO: add support for listing DNs for trusted CAs */
738 	WPA_PUT_BE16(pos, 0);
739 	pos += 2;
740 
741 	WPA_PUT_BE24(hs_length, pos - hs_length - 3);
742 
743 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
744 			      rhdr, end - rhdr, hs_start, pos - hs_start,
745 			      &rlen) < 0) {
746 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
747 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
748 				   TLS_ALERT_INTERNAL_ERROR);
749 		return -1;
750 	}
751 	pos = rhdr + rlen;
752 
753 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
754 
755 	*msgpos = pos;
756 
757 	return 0;
758 }
759 
760 
tls_write_server_hello_done(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)761 static int tls_write_server_hello_done(struct tlsv1_server *conn,
762 				       u8 **msgpos, u8 *end)
763 {
764 	u8 *pos;
765 	size_t rlen;
766 	u8 payload[4];
767 
768 	tlsv1_server_log(conn, "Send ServerHelloDone");
769 
770 	/* opaque fragment[TLSPlaintext.length] */
771 
772 	/* Handshake */
773 	pos = payload;
774 	/* HandshakeType msg_type */
775 	*pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO_DONE;
776 	/* uint24 length */
777 	WPA_PUT_BE24(pos, 0);
778 	pos += 3;
779 	/* body - ServerHelloDone (empty) */
780 
781 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
782 			      *msgpos, end - *msgpos, payload, pos - payload,
783 			      &rlen) < 0) {
784 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
785 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
786 				   TLS_ALERT_INTERNAL_ERROR);
787 		return -1;
788 	}
789 
790 	tls_verify_hash_add(&conn->verify, payload, pos - payload);
791 
792 	*msgpos += rlen;
793 
794 	return 0;
795 }
796 
797 
tls_write_server_change_cipher_spec(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)798 static int tls_write_server_change_cipher_spec(struct tlsv1_server *conn,
799 					       u8 **msgpos, u8 *end)
800 {
801 	size_t rlen;
802 	u8 payload[1];
803 
804 	tlsv1_server_log(conn, "Send ChangeCipherSpec");
805 
806 	payload[0] = TLS_CHANGE_CIPHER_SPEC;
807 
808 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC,
809 			      *msgpos, end - *msgpos, payload, sizeof(payload),
810 			      &rlen) < 0) {
811 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
812 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
813 				   TLS_ALERT_INTERNAL_ERROR);
814 		return -1;
815 	}
816 
817 	if (tlsv1_record_change_write_cipher(&conn->rl) < 0) {
818 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to set write cipher for "
819 			   "record layer");
820 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
821 				   TLS_ALERT_INTERNAL_ERROR);
822 		return -1;
823 	}
824 
825 	*msgpos += rlen;
826 
827 	return 0;
828 }
829 
830 
tls_write_server_finished(struct tlsv1_server * conn,u8 ** msgpos,u8 * end)831 static int tls_write_server_finished(struct tlsv1_server *conn,
832 				     u8 **msgpos, u8 *end)
833 {
834 	u8 *pos, *hs_start;
835 	size_t rlen, hlen;
836 	u8 verify_data[1 + 3 + TLS_VERIFY_DATA_LEN];
837 	u8 hash[MD5_MAC_LEN + SHA1_MAC_LEN];
838 
839 	pos = *msgpos;
840 
841 	tlsv1_server_log(conn, "Send Finished");
842 
843 	/* Encrypted Handshake Message: Finished */
844 
845 #ifdef CONFIG_TLSV12
846 	if (conn->rl.tls_version >= TLS_VERSION_1_2) {
847 		hlen = SHA256_MAC_LEN;
848 		if (conn->verify.sha256_server == NULL ||
849 		    crypto_hash_finish(conn->verify.sha256_server, hash, &hlen)
850 		    < 0) {
851 			conn->verify.sha256_server = NULL;
852 			tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
853 					   TLS_ALERT_INTERNAL_ERROR);
854 			return -1;
855 		}
856 		conn->verify.sha256_server = NULL;
857 	} else {
858 #endif /* CONFIG_TLSV12 */
859 
860 	hlen = MD5_MAC_LEN;
861 	if (conn->verify.md5_server == NULL ||
862 	    crypto_hash_finish(conn->verify.md5_server, hash, &hlen) < 0) {
863 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
864 				   TLS_ALERT_INTERNAL_ERROR);
865 		conn->verify.md5_server = NULL;
866 		crypto_hash_finish(conn->verify.sha1_server, NULL, NULL);
867 		conn->verify.sha1_server = NULL;
868 		return -1;
869 	}
870 	conn->verify.md5_server = NULL;
871 	hlen = SHA1_MAC_LEN;
872 	if (conn->verify.sha1_server == NULL ||
873 	    crypto_hash_finish(conn->verify.sha1_server, hash + MD5_MAC_LEN,
874 			       &hlen) < 0) {
875 		conn->verify.sha1_server = NULL;
876 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
877 				   TLS_ALERT_INTERNAL_ERROR);
878 		return -1;
879 	}
880 	conn->verify.sha1_server = NULL;
881 	hlen = MD5_MAC_LEN + SHA1_MAC_LEN;
882 
883 #ifdef CONFIG_TLSV12
884 	}
885 #endif /* CONFIG_TLSV12 */
886 
887 	if (tls_prf(conn->rl.tls_version,
888 		    conn->master_secret, TLS_MASTER_SECRET_LEN,
889 		    "server finished", hash, hlen,
890 		    verify_data + 1 + 3, TLS_VERIFY_DATA_LEN)) {
891 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate verify_data");
892 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
893 				   TLS_ALERT_INTERNAL_ERROR);
894 		return -1;
895 	}
896 	wpa_hexdump_key(MSG_DEBUG, "TLSv1: verify_data (server)",
897 			verify_data + 1 + 3, TLS_VERIFY_DATA_LEN);
898 #ifdef CONFIG_TESTING_OPTIONS
899 	if (conn->test_flags & TLS_BREAK_VERIFY_DATA) {
900 		tlsv1_server_log(conn, "TESTING: Break verify_data (server)");
901 		verify_data[1 + 3 + 1] ^= 0x80;
902 	}
903 #endif /* CONFIG_TESTING_OPTIONS */
904 
905 	/* Handshake */
906 	pos = hs_start = verify_data;
907 	/* HandshakeType msg_type */
908 	*pos++ = TLS_HANDSHAKE_TYPE_FINISHED;
909 	/* uint24 length */
910 	WPA_PUT_BE24(pos, TLS_VERIFY_DATA_LEN);
911 	pos += 3;
912 	pos += TLS_VERIFY_DATA_LEN;
913 	tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
914 
915 	if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
916 			      *msgpos, end - *msgpos, hs_start, pos - hs_start,
917 			      &rlen) < 0) {
918 		wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
919 		tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
920 				   TLS_ALERT_INTERNAL_ERROR);
921 		return -1;
922 	}
923 
924 	*msgpos += rlen;
925 
926 	return 0;
927 }
928 
929 
tls_send_server_hello(struct tlsv1_server * conn,size_t * out_len)930 static u8 * tls_send_server_hello(struct tlsv1_server *conn, size_t *out_len)
931 {
932 	u8 *msg, *end, *pos;
933 	size_t msglen;
934 	int ocsp_multi = 0;
935 	char *ocsp_resp = NULL;
936 	size_t ocsp_resp_len = 0;
937 
938 	*out_len = 0;
939 
940 	if (conn->status_request_multi &&
941 	    conn->cred->ocsp_stapling_response_multi) {
942 		ocsp_resp = os_readfile(
943 			conn->cred->ocsp_stapling_response_multi,
944 			&ocsp_resp_len);
945 		ocsp_multi = 1;
946 	} else if ((conn->status_request || conn->status_request_v2) &&
947 		   conn->cred->ocsp_stapling_response) {
948 		ocsp_resp = os_readfile(conn->cred->ocsp_stapling_response,
949 					&ocsp_resp_len);
950 	}
951 	if (!ocsp_resp)
952 		ocsp_resp_len = 0;
953 
954 	msglen = 1000 + tls_server_cert_chain_der_len(conn) + ocsp_resp_len;
955 
956 	msg = os_malloc(msglen);
957 	if (msg == NULL) {
958 		os_free(ocsp_resp);
959 		return NULL;
960 	}
961 
962 	pos = msg;
963 	end = msg + msglen;
964 
965 	if (tls_write_server_hello(conn, &pos, end) < 0) {
966 		os_free(msg);
967 		os_free(ocsp_resp);
968 		return NULL;
969 	}
970 
971 	if (conn->use_session_ticket) {
972 		os_free(ocsp_resp);
973 
974 		/* Abbreviated handshake using session ticket; RFC 4507 */
975 		if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
976 		    tls_write_server_finished(conn, &pos, end) < 0) {
977 			os_free(msg);
978 			return NULL;
979 		}
980 
981 		*out_len = pos - msg;
982 
983 		conn->state = CHANGE_CIPHER_SPEC;
984 
985 		return msg;
986 	}
987 
988 	/* Full handshake */
989 	if (tls_write_server_certificate(conn, &pos, end) < 0 ||
990 	    tls_write_server_certificate_status(conn, &pos, end, ocsp_multi,
991 						ocsp_resp, ocsp_resp_len) < 0 ||
992 	    tls_write_server_key_exchange(conn, &pos, end) < 0 ||
993 	    tls_write_server_certificate_request(conn, &pos, end) < 0 ||
994 	    tls_write_server_hello_done(conn, &pos, end) < 0) {
995 		os_free(msg);
996 		os_free(ocsp_resp);
997 		return NULL;
998 	}
999 	os_free(ocsp_resp);
1000 
1001 	*out_len = pos - msg;
1002 
1003 	conn->state = CLIENT_CERTIFICATE;
1004 
1005 	return msg;
1006 }
1007 
1008 
tls_send_change_cipher_spec(struct tlsv1_server * conn,size_t * out_len)1009 static u8 * tls_send_change_cipher_spec(struct tlsv1_server *conn,
1010 					size_t *out_len)
1011 {
1012 	u8 *msg, *end, *pos;
1013 
1014 	*out_len = 0;
1015 
1016 	msg = os_malloc(1000);
1017 	if (msg == NULL)
1018 		return NULL;
1019 
1020 	pos = msg;
1021 	end = msg + 1000;
1022 
1023 	if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
1024 	    tls_write_server_finished(conn, &pos, end) < 0) {
1025 		os_free(msg);
1026 		return NULL;
1027 	}
1028 
1029 	*out_len = pos - msg;
1030 
1031 	tlsv1_server_log(conn, "Handshake completed successfully");
1032 	conn->state = ESTABLISHED;
1033 
1034 	return msg;
1035 }
1036 
1037 
tlsv1_server_handshake_write(struct tlsv1_server * conn,size_t * out_len)1038 u8 * tlsv1_server_handshake_write(struct tlsv1_server *conn, size_t *out_len)
1039 {
1040 	switch (conn->state) {
1041 	case SERVER_HELLO:
1042 		return tls_send_server_hello(conn, out_len);
1043 	case SERVER_CHANGE_CIPHER_SPEC:
1044 		return tls_send_change_cipher_spec(conn, out_len);
1045 	default:
1046 		if (conn->state == ESTABLISHED && conn->use_session_ticket) {
1047 			/* Abbreviated handshake was already completed. */
1048 			return NULL;
1049 		}
1050 		tlsv1_server_log(conn, "Unexpected state %d while generating reply",
1051 				 conn->state);
1052 		return NULL;
1053 	}
1054 }
1055 
1056 
tlsv1_server_send_alert(struct tlsv1_server * conn,u8 level,u8 description,size_t * out_len)1057 u8 * tlsv1_server_send_alert(struct tlsv1_server *conn, u8 level,
1058 			     u8 description, size_t *out_len)
1059 {
1060 	u8 *alert, *pos, *length;
1061 
1062 	tlsv1_server_log(conn, "Send Alert(%d:%d)", level, description);
1063 	*out_len = 0;
1064 
1065 	alert = os_malloc(10);
1066 	if (alert == NULL)
1067 		return NULL;
1068 
1069 	pos = alert;
1070 
1071 	/* TLSPlaintext */
1072 	/* ContentType type */
1073 	*pos++ = TLS_CONTENT_TYPE_ALERT;
1074 	/* ProtocolVersion version */
1075 	WPA_PUT_BE16(pos, conn->rl.tls_version ? conn->rl.tls_version :
1076 		     TLS_VERSION);
1077 	pos += 2;
1078 	/* uint16 length (to be filled) */
1079 	length = pos;
1080 	pos += 2;
1081 	/* opaque fragment[TLSPlaintext.length] */
1082 
1083 	/* Alert */
1084 	/* AlertLevel level */
1085 	*pos++ = level;
1086 	/* AlertDescription description */
1087 	*pos++ = description;
1088 
1089 	WPA_PUT_BE16(length, pos - length - 2);
1090 	*out_len = pos - alert;
1091 
1092 	return alert;
1093 }
1094