2 * TLSv1 server - write handshake message
3 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Alternatively, this software may be distributed under the terms of BSD
12 * See README and COPYING for more details.
22 #include "tlsv1_common.h"
23 #include "tlsv1_record.h"
24 #include "tlsv1_server.h"
25 #include "tlsv1_server_i.h"
28 static size_t tls_server_cert_chain_der_len(struct tlsv1_server *conn)
31 struct x509_certificate *cert;
33 cert = conn->cred->cert;
35 len += 3 + cert->cert_len;
36 if (x509_certificate_self_signed(cert))
38 cert = x509_certificate_get_subject(conn->cred->trusted_certs,
46 static int tls_write_server_hello(struct tlsv1_server *conn,
49 u8 *pos, *rhdr, *hs_start, *hs_length;
55 wpa_printf(MSG_DEBUG, "TLSv1: Send ServerHello");
57 pos += TLS_RECORD_HEADER_LEN;
60 WPA_PUT_BE32(conn->server_random, now.sec);
61 if (os_get_random(conn->server_random + 4, TLS_RANDOM_LEN - 4)) {
62 wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
66 wpa_hexdump(MSG_MSGDUMP, "TLSv1: server_random",
67 conn->server_random, TLS_RANDOM_LEN);
69 conn->session_id_len = TLS_SESSION_ID_MAX_LEN;
70 if (os_get_random(conn->session_id, conn->session_id_len)) {
71 wpa_printf(MSG_ERROR, "TLSv1: Could not generate "
75 wpa_hexdump(MSG_MSGDUMP, "TLSv1: session_id",
76 conn->session_id, conn->session_id_len);
78 /* opaque fragment[TLSPlaintext.length] */
82 /* HandshakeType msg_type */
83 *pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO;
84 /* uint24 length (to be filled) */
87 /* body - ServerHello */
88 /* ProtocolVersion server_version */
89 WPA_PUT_BE16(pos, TLS_VERSION);
91 /* Random random: uint32 gmt_unix_time, opaque random_bytes */
92 os_memcpy(pos, conn->server_random, TLS_RANDOM_LEN);
93 pos += TLS_RANDOM_LEN;
94 /* SessionID session_id */
95 *pos++ = conn->session_id_len;
96 os_memcpy(pos, conn->session_id, conn->session_id_len);
97 pos += conn->session_id_len;
98 /* CipherSuite cipher_suite */
99 WPA_PUT_BE16(pos, conn->cipher_suite);
101 /* CompressionMethod compression_method */
102 *pos++ = TLS_COMPRESSION_NULL;
104 if (conn->session_ticket && conn->session_ticket_cb) {
105 int res = conn->session_ticket_cb(
106 conn->session_ticket_cb_ctx,
107 conn->session_ticket, conn->session_ticket_len,
108 conn->client_random, conn->server_random,
109 conn->master_secret);
111 wpa_printf(MSG_DEBUG, "TLSv1: SessionTicket callback "
112 "indicated failure");
113 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
114 TLS_ALERT_HANDSHAKE_FAILURE);
117 conn->use_session_ticket = res;
119 if (conn->use_session_ticket) {
120 if (tlsv1_server_derive_keys(conn, NULL, 0) < 0) {
121 wpa_printf(MSG_DEBUG, "TLSv1: Failed to "
123 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
124 TLS_ALERT_INTERNAL_ERROR);
130 * RFC 4507 specifies that server would include an empty
131 * SessionTicket extension in ServerHello and a
132 * NewSessionTicket message after the ServerHello. However,
133 * EAP-FAST (RFC 4851), i.e., the only user of SessionTicket
134 * extension at the moment, does not use such extensions.
136 * TODO: Add support for configuring RFC 4507 behavior and make
137 * EAP-FAST disable it.
141 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
142 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
144 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
145 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
146 wpa_printf(MSG_DEBUG, "TLSv1: Failed to create TLS record");
147 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
148 TLS_ALERT_INTERNAL_ERROR);
159 static int tls_write_server_certificate(struct tlsv1_server *conn,
160 u8 **msgpos, u8 *end)
162 u8 *pos, *rhdr, *hs_start, *hs_length, *cert_start;
164 struct x509_certificate *cert;
165 const struct tls_cipher_suite *suite;
167 suite = tls_get_cipher_suite(conn->rl.cipher_suite);
168 if (suite && suite->key_exchange == TLS_KEY_X_DH_anon) {
169 wpa_printf(MSG_DEBUG, "TLSv1: Do not send Certificate when "
170 "using anonymous DH");
176 wpa_printf(MSG_DEBUG, "TLSv1: Send Certificate");
178 pos += TLS_RECORD_HEADER_LEN;
180 /* opaque fragment[TLSPlaintext.length] */
184 /* HandshakeType msg_type */
185 *pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE;
186 /* uint24 length (to be filled) */
189 /* body - Certificate */
190 /* uint24 length (to be filled) */
193 cert = conn->cred->cert;
195 if (pos + 3 + cert->cert_len > end) {
196 wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space "
197 "for Certificate (cert_len=%lu left=%lu)",
198 (unsigned long) cert->cert_len,
199 (unsigned long) (end - pos));
200 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
201 TLS_ALERT_INTERNAL_ERROR);
204 WPA_PUT_BE24(pos, cert->cert_len);
206 os_memcpy(pos, cert->cert_start, cert->cert_len);
207 pos += cert->cert_len;
209 if (x509_certificate_self_signed(cert))
211 cert = x509_certificate_get_subject(conn->cred->trusted_certs,
214 if (cert == conn->cred->cert || cert == NULL) {
216 * Server was not configured with all the needed certificates
217 * to form a full certificate chain. The client may fail to
218 * validate the chain unless it is configured with all the
219 * missing CA certificates.
221 wpa_printf(MSG_DEBUG, "TLSv1: Full server certificate chain "
222 "not configured - validation may fail");
224 WPA_PUT_BE24(cert_start, pos - cert_start - 3);
226 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
228 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
229 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
230 wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
231 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
232 TLS_ALERT_INTERNAL_ERROR);
237 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
245 static int tls_write_server_key_exchange(struct tlsv1_server *conn,
246 u8 **msgpos, u8 *end)
248 tls_key_exchange keyx;
249 const struct tls_cipher_suite *suite;
251 u8 *pos, *rhdr, *hs_start, *hs_length;
255 #endif /* EAP_FAST */
257 suite = tls_get_cipher_suite(conn->rl.cipher_suite);
259 keyx = TLS_KEY_X_NULL;
261 keyx = suite->key_exchange;
263 if (!tls_server_key_exchange_allowed(conn->rl.cipher_suite)) {
264 wpa_printf(MSG_DEBUG, "TLSv1: No ServerKeyExchange needed");
268 if (keyx != TLS_KEY_X_DH_anon) {
270 wpa_printf(MSG_DEBUG, "TLSv1: ServerKeyExchange not yet "
271 "supported with key exchange type %d", keyx);
276 if (conn->cred == NULL || conn->cred->dh_p == NULL ||
277 conn->cred->dh_g == NULL) {
278 wpa_printf(MSG_DEBUG, "TLSv1: No DH parameters available for "
279 "ServerKeyExhcange");
283 os_free(conn->dh_secret);
284 conn->dh_secret_len = conn->cred->dh_p_len;
285 conn->dh_secret = os_malloc(conn->dh_secret_len);
286 if (conn->dh_secret == NULL) {
287 wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate "
288 "memory for secret (Diffie-Hellman)");
289 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
290 TLS_ALERT_INTERNAL_ERROR);
293 if (os_get_random(conn->dh_secret, conn->dh_secret_len)) {
294 wpa_printf(MSG_DEBUG, "TLSv1: Failed to get random "
295 "data for Diffie-Hellman");
296 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
297 TLS_ALERT_INTERNAL_ERROR);
298 os_free(conn->dh_secret);
299 conn->dh_secret = NULL;
303 if (os_memcmp(conn->dh_secret, conn->cred->dh_p, conn->dh_secret_len) >
305 conn->dh_secret[0] = 0; /* make sure secret < p */
307 pos = conn->dh_secret;
308 while (pos + 1 < conn->dh_secret + conn->dh_secret_len && *pos == 0)
310 if (pos != conn->dh_secret) {
311 os_memmove(conn->dh_secret, pos,
312 conn->dh_secret_len - (pos - conn->dh_secret));
313 conn->dh_secret_len -= pos - conn->dh_secret;
315 wpa_hexdump_key(MSG_DEBUG, "TLSv1: DH server's secret value",
316 conn->dh_secret, conn->dh_secret_len);
318 /* Ys = g^secret mod p */
319 dh_ys_len = conn->cred->dh_p_len;
320 dh_ys = os_malloc(dh_ys_len);
322 wpa_printf(MSG_DEBUG, "TLSv1: Failed to allocate memory for "
324 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
325 TLS_ALERT_INTERNAL_ERROR);
328 if (crypto_mod_exp(conn->cred->dh_g, conn->cred->dh_g_len,
329 conn->dh_secret, conn->dh_secret_len,
330 conn->cred->dh_p, conn->cred->dh_p_len,
331 dh_ys, &dh_ys_len)) {
332 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
333 TLS_ALERT_INTERNAL_ERROR);
338 wpa_hexdump(MSG_DEBUG, "TLSv1: DH Ys (server's public value)",
343 * select (KeyExchangeAlgorithm) {
344 * case diffie_hellman:
345 * ServerDHParams params;
346 * Signature signed_params;
348 * ServerRSAParams params;
349 * Signature signed_params;
351 * } ServerKeyExchange;
354 * opaque dh_p<1..2^16-1>;
355 * opaque dh_g<1..2^16-1>;
356 * opaque dh_Ys<1..2^16-1>;
362 wpa_printf(MSG_DEBUG, "TLSv1: Send ServerKeyExchange");
364 pos += TLS_RECORD_HEADER_LEN;
366 /* opaque fragment[TLSPlaintext.length] */
370 /* HandshakeType msg_type */
371 *pos++ = TLS_HANDSHAKE_TYPE_SERVER_KEY_EXCHANGE;
372 /* uint24 length (to be filled) */
376 /* body - ServerDHParams */
378 if (pos + 2 + conn->cred->dh_p_len > end) {
379 wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
381 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
382 TLS_ALERT_INTERNAL_ERROR);
386 WPA_PUT_BE16(pos, conn->cred->dh_p_len);
388 os_memcpy(pos, conn->cred->dh_p, conn->cred->dh_p_len);
389 pos += conn->cred->dh_p_len;
392 if (pos + 2 + conn->cred->dh_g_len > end) {
393 wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
395 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
396 TLS_ALERT_INTERNAL_ERROR);
400 WPA_PUT_BE16(pos, conn->cred->dh_g_len);
402 os_memcpy(pos, conn->cred->dh_g, conn->cred->dh_g_len);
403 pos += conn->cred->dh_g_len;
406 if (pos + 2 + dh_ys_len > end) {
407 wpa_printf(MSG_DEBUG, "TLSv1: Not enough buffer space for "
409 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
410 TLS_ALERT_INTERNAL_ERROR);
414 WPA_PUT_BE16(pos, dh_ys_len);
416 os_memcpy(pos, dh_ys, dh_ys_len);
420 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
422 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
423 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
424 wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
425 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
426 TLS_ALERT_INTERNAL_ERROR);
431 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
438 #endif /* EAP_FAST */
442 static int tls_write_server_certificate_request(struct tlsv1_server *conn,
443 u8 **msgpos, u8 *end)
445 u8 *pos, *rhdr, *hs_start, *hs_length;
448 if (!conn->verify_peer) {
449 wpa_printf(MSG_DEBUG, "TLSv1: No CertificateRequest needed");
455 wpa_printf(MSG_DEBUG, "TLSv1: Send CertificateRequest");
457 pos += TLS_RECORD_HEADER_LEN;
459 /* opaque fragment[TLSPlaintext.length] */
463 /* HandshakeType msg_type */
464 *pos++ = TLS_HANDSHAKE_TYPE_CERTIFICATE_REQUEST;
465 /* uint24 length (to be filled) */
468 /* body - CertificateRequest */
472 * rsa_sign(1), dss_sign(2), rsa_fixed_dh(3), dss_fixed_dh(4),
474 * } ClientCertificateType;
475 * ClientCertificateType certificate_types<1..2^8-1>
478 *pos++ = 1; /* rsa_sign */
481 * opaque DistinguishedName<1..2^16-1>
482 * DistinguishedName certificate_authorities<3..2^16-1>
484 /* TODO: add support for listing DNs for trusted CAs */
485 WPA_PUT_BE16(pos, 0);
488 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
490 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
491 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
492 wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
493 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
494 TLS_ALERT_INTERNAL_ERROR);
499 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
507 static int tls_write_server_hello_done(struct tlsv1_server *conn,
508 u8 **msgpos, u8 *end)
510 u8 *pos, *rhdr, *hs_start, *hs_length;
515 wpa_printf(MSG_DEBUG, "TLSv1: Send ServerHelloDone");
517 pos += TLS_RECORD_HEADER_LEN;
519 /* opaque fragment[TLSPlaintext.length] */
523 /* HandshakeType msg_type */
524 *pos++ = TLS_HANDSHAKE_TYPE_SERVER_HELLO_DONE;
525 /* uint24 length (to be filled) */
528 /* body - ServerHelloDone (empty) */
530 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
532 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
533 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
534 wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate a record");
535 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
536 TLS_ALERT_INTERNAL_ERROR);
541 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
549 static int tls_write_server_change_cipher_spec(struct tlsv1_server *conn,
550 u8 **msgpos, u8 *end)
557 wpa_printf(MSG_DEBUG, "TLSv1: Send ChangeCipherSpec");
559 pos += TLS_RECORD_HEADER_LEN;
560 *pos = TLS_CHANGE_CIPHER_SPEC;
561 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC,
562 rhdr, end - rhdr, 1, &rlen) < 0) {
563 wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
564 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
565 TLS_ALERT_INTERNAL_ERROR);
569 if (tlsv1_record_change_write_cipher(&conn->rl) < 0) {
570 wpa_printf(MSG_DEBUG, "TLSv1: Failed to set write cipher for "
572 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
573 TLS_ALERT_INTERNAL_ERROR);
577 *msgpos = rhdr + rlen;
583 static int tls_write_server_finished(struct tlsv1_server *conn,
584 u8 **msgpos, u8 *end)
586 u8 *pos, *rhdr, *hs_start, *hs_length;
588 u8 verify_data[TLS_VERIFY_DATA_LEN];
589 u8 hash[MD5_MAC_LEN + SHA1_MAC_LEN];
593 wpa_printf(MSG_DEBUG, "TLSv1: Send Finished");
595 /* Encrypted Handshake Message: Finished */
598 if (conn->verify.md5_server == NULL ||
599 crypto_hash_finish(conn->verify.md5_server, hash, &hlen) < 0) {
600 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
601 TLS_ALERT_INTERNAL_ERROR);
602 conn->verify.md5_server = NULL;
603 crypto_hash_finish(conn->verify.sha1_server, NULL, NULL);
604 conn->verify.sha1_server = NULL;
607 conn->verify.md5_server = NULL;
609 if (conn->verify.sha1_server == NULL ||
610 crypto_hash_finish(conn->verify.sha1_server, hash + MD5_MAC_LEN,
612 conn->verify.sha1_server = NULL;
613 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
614 TLS_ALERT_INTERNAL_ERROR);
617 conn->verify.sha1_server = NULL;
619 if (tls_prf(conn->master_secret, TLS_MASTER_SECRET_LEN,
620 "server finished", hash, MD5_MAC_LEN + SHA1_MAC_LEN,
621 verify_data, TLS_VERIFY_DATA_LEN)) {
622 wpa_printf(MSG_DEBUG, "TLSv1: Failed to generate verify_data");
623 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
624 TLS_ALERT_INTERNAL_ERROR);
627 wpa_hexdump_key(MSG_DEBUG, "TLSv1: verify_data (server)",
628 verify_data, TLS_VERIFY_DATA_LEN);
631 pos += TLS_RECORD_HEADER_LEN;
634 /* HandshakeType msg_type */
635 *pos++ = TLS_HANDSHAKE_TYPE_FINISHED;
636 /* uint24 length (to be filled) */
639 os_memcpy(pos, verify_data, TLS_VERIFY_DATA_LEN);
640 pos += TLS_VERIFY_DATA_LEN;
641 WPA_PUT_BE24(hs_length, pos - hs_length - 3);
642 tls_verify_hash_add(&conn->verify, hs_start, pos - hs_start);
644 if (tlsv1_record_send(&conn->rl, TLS_CONTENT_TYPE_HANDSHAKE,
645 rhdr, end - rhdr, pos - hs_start, &rlen) < 0) {
646 wpa_printf(MSG_DEBUG, "TLSv1: Failed to create a record");
647 tlsv1_server_alert(conn, TLS_ALERT_LEVEL_FATAL,
648 TLS_ALERT_INTERNAL_ERROR);
660 static u8 * tls_send_server_hello(struct tlsv1_server *conn, size_t *out_len)
667 msglen = 1000 + tls_server_cert_chain_der_len(conn);
669 msg = os_malloc(msglen);
676 if (tls_write_server_hello(conn, &pos, end) < 0) {
681 if (conn->use_session_ticket) {
682 /* Abbreviated handshake using session ticket; RFC 4507 */
683 if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
684 tls_write_server_finished(conn, &pos, end) < 0) {
689 *out_len = pos - msg;
691 conn->state = CHANGE_CIPHER_SPEC;
697 if (tls_write_server_certificate(conn, &pos, end) < 0 ||
698 tls_write_server_key_exchange(conn, &pos, end) < 0 ||
699 tls_write_server_certificate_request(conn, &pos, end) < 0 ||
700 tls_write_server_hello_done(conn, &pos, end) < 0) {
705 *out_len = pos - msg;
707 conn->state = CLIENT_CERTIFICATE;
713 static u8 * tls_send_change_cipher_spec(struct tlsv1_server *conn,
720 msg = os_malloc(1000);
727 if (tls_write_server_change_cipher_spec(conn, &pos, end) < 0 ||
728 tls_write_server_finished(conn, &pos, end) < 0) {
733 *out_len = pos - msg;
735 wpa_printf(MSG_DEBUG, "TLSv1: Handshake completed successfully");
736 conn->state = ESTABLISHED;
742 u8 * tlsv1_server_handshake_write(struct tlsv1_server *conn, size_t *out_len)
744 switch (conn->state) {
746 return tls_send_server_hello(conn, out_len);
747 case SERVER_CHANGE_CIPHER_SPEC:
748 return tls_send_change_cipher_spec(conn, out_len);
750 if (conn->state == ESTABLISHED && conn->use_session_ticket) {
751 /* Abbreviated handshake was already completed. */
754 wpa_printf(MSG_DEBUG, "TLSv1: Unexpected state %d while "
755 "generating reply", conn->state);
761 u8 * tlsv1_server_send_alert(struct tlsv1_server *conn, u8 level,
762 u8 description, size_t *out_len)
764 u8 *alert, *pos, *length;
766 wpa_printf(MSG_DEBUG, "TLSv1: Send Alert(%d:%d)", level, description);
769 alert = os_malloc(10);
776 /* ContentType type */
777 *pos++ = TLS_CONTENT_TYPE_ALERT;
778 /* ProtocolVersion version */
779 WPA_PUT_BE16(pos, TLS_VERSION);
781 /* uint16 length (to be filled) */
784 /* opaque fragment[TLSPlaintext.length] */
787 /* AlertLevel level */
789 /* AlertDescription description */
790 *pos++ = description;
792 WPA_PUT_BE16(length, pos - length - 2);
793 *out_len = pos - alert;