1 | /* |
2 | * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved. |
3 | * |
4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
5 | * this file except in compliance with the License. You can obtain a copy |
6 | * in the file LICENSE in the source distribution or at |
7 | * https://www.openssl.org/source/license.html |
8 | */ |
9 | |
10 | #include "e_os.h" |
11 | #include <stdio.h> |
12 | #include <openssl/objects.h> |
13 | #include <openssl/rand.h> |
14 | #include "ssl_local.h" |
15 | |
16 | static void get_current_time(struct timeval *t); |
17 | static int dtls1_handshake_write(SSL *s); |
18 | static size_t dtls1_link_min_mtu(void); |
19 | |
20 | /* XDTLS: figure out the right values */ |
21 | static const size_t g_probable_mtu[] = { 1500, 512, 256 }; |
22 | |
23 | const SSL3_ENC_METHOD DTLSv1_enc_data = { |
24 | tls1_enc, |
25 | tls1_mac, |
26 | tls1_setup_key_block, |
27 | tls1_generate_master_secret, |
28 | tls1_change_cipher_state, |
29 | tls1_final_finish_mac, |
30 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, |
31 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, |
32 | tls1_alert_code, |
33 | tls1_export_keying_material, |
34 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV, |
35 | dtls1_set_handshake_header, |
36 | dtls1_close_construct_packet, |
37 | dtls1_handshake_write |
38 | }; |
39 | |
40 | const SSL3_ENC_METHOD DTLSv1_2_enc_data = { |
41 | tls1_enc, |
42 | tls1_mac, |
43 | tls1_setup_key_block, |
44 | tls1_generate_master_secret, |
45 | tls1_change_cipher_state, |
46 | tls1_final_finish_mac, |
47 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, |
48 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, |
49 | tls1_alert_code, |
50 | tls1_export_keying_material, |
51 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS |
52 | | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS, |
53 | dtls1_set_handshake_header, |
54 | dtls1_close_construct_packet, |
55 | dtls1_handshake_write |
56 | }; |
57 | |
58 | long dtls1_default_timeout(void) |
59 | { |
60 | /* |
61 | * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for |
62 | * http, the cache would over fill |
63 | */ |
64 | return (60 * 60 * 2); |
65 | } |
66 | |
67 | int dtls1_new(SSL *s) |
68 | { |
69 | DTLS1_STATE *d1; |
70 | |
71 | if (!DTLS_RECORD_LAYER_new(&s->rlayer)) { |
72 | return 0; |
73 | } |
74 | |
75 | if (!ssl3_new(s)) |
76 | return 0; |
77 | if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) { |
78 | ssl3_free(s); |
79 | return 0; |
80 | } |
81 | |
82 | d1->buffered_messages = pqueue_new(); |
83 | d1->sent_messages = pqueue_new(); |
84 | |
85 | if (s->server) { |
86 | d1->cookie_len = sizeof(s->d1->cookie); |
87 | } |
88 | |
89 | d1->link_mtu = 0; |
90 | d1->mtu = 0; |
91 | |
92 | if (d1->buffered_messages == NULL || d1->sent_messages == NULL) { |
93 | pqueue_free(d1->buffered_messages); |
94 | pqueue_free(d1->sent_messages); |
95 | OPENSSL_free(d1); |
96 | ssl3_free(s); |
97 | return 0; |
98 | } |
99 | |
100 | s->d1 = d1; |
101 | |
102 | if (!s->method->ssl_clear(s)) |
103 | return 0; |
104 | |
105 | return 1; |
106 | } |
107 | |
108 | static void dtls1_clear_queues(SSL *s) |
109 | { |
110 | dtls1_clear_received_buffer(s); |
111 | dtls1_clear_sent_buffer(s); |
112 | } |
113 | |
114 | void dtls1_clear_received_buffer(SSL *s) |
115 | { |
116 | pitem *item = NULL; |
117 | hm_fragment *frag = NULL; |
118 | |
119 | while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) { |
120 | frag = (hm_fragment *)item->data; |
121 | dtls1_hm_fragment_free(frag); |
122 | pitem_free(item); |
123 | } |
124 | } |
125 | |
126 | void dtls1_clear_sent_buffer(SSL *s) |
127 | { |
128 | pitem *item = NULL; |
129 | hm_fragment *frag = NULL; |
130 | |
131 | while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { |
132 | frag = (hm_fragment *)item->data; |
133 | dtls1_hm_fragment_free(frag); |
134 | pitem_free(item); |
135 | } |
136 | } |
137 | |
138 | |
139 | void dtls1_free(SSL *s) |
140 | { |
141 | DTLS_RECORD_LAYER_free(&s->rlayer); |
142 | |
143 | ssl3_free(s); |
144 | |
145 | dtls1_clear_queues(s); |
146 | |
147 | pqueue_free(s->d1->buffered_messages); |
148 | pqueue_free(s->d1->sent_messages); |
149 | |
150 | OPENSSL_free(s->d1); |
151 | s->d1 = NULL; |
152 | } |
153 | |
154 | int dtls1_clear(SSL *s) |
155 | { |
156 | pqueue *buffered_messages; |
157 | pqueue *sent_messages; |
158 | size_t mtu; |
159 | size_t link_mtu; |
160 | |
161 | DTLS_RECORD_LAYER_clear(&s->rlayer); |
162 | |
163 | if (s->d1) { |
164 | DTLS_timer_cb timer_cb = s->d1->timer_cb; |
165 | |
166 | buffered_messages = s->d1->buffered_messages; |
167 | sent_messages = s->d1->sent_messages; |
168 | mtu = s->d1->mtu; |
169 | link_mtu = s->d1->link_mtu; |
170 | |
171 | dtls1_clear_queues(s); |
172 | |
173 | memset(s->d1, 0, sizeof(*s->d1)); |
174 | |
175 | /* Restore the timer callback from previous state */ |
176 | s->d1->timer_cb = timer_cb; |
177 | |
178 | if (s->server) { |
179 | s->d1->cookie_len = sizeof(s->d1->cookie); |
180 | } |
181 | |
182 | if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { |
183 | s->d1->mtu = mtu; |
184 | s->d1->link_mtu = link_mtu; |
185 | } |
186 | |
187 | s->d1->buffered_messages = buffered_messages; |
188 | s->d1->sent_messages = sent_messages; |
189 | } |
190 | |
191 | if (!ssl3_clear(s)) |
192 | return 0; |
193 | |
194 | if (s->method->version == DTLS_ANY_VERSION) |
195 | s->version = DTLS_MAX_VERSION_INTERNAL; |
196 | #ifndef OPENSSL_NO_DTLS1_METHOD |
197 | else if (s->options & SSL_OP_CISCO_ANYCONNECT) |
198 | s->client_version = s->version = DTLS1_BAD_VER; |
199 | #endif |
200 | else |
201 | s->version = s->method->version; |
202 | |
203 | return 1; |
204 | } |
205 | |
206 | long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) |
207 | { |
208 | int ret = 0; |
209 | |
210 | switch (cmd) { |
211 | case DTLS_CTRL_GET_TIMEOUT: |
212 | if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) { |
213 | ret = 1; |
214 | } |
215 | break; |
216 | case DTLS_CTRL_HANDLE_TIMEOUT: |
217 | ret = dtls1_handle_timeout(s); |
218 | break; |
219 | case DTLS_CTRL_SET_LINK_MTU: |
220 | if (larg < (long)dtls1_link_min_mtu()) |
221 | return 0; |
222 | s->d1->link_mtu = larg; |
223 | return 1; |
224 | case DTLS_CTRL_GET_LINK_MIN_MTU: |
225 | return (long)dtls1_link_min_mtu(); |
226 | case SSL_CTRL_SET_MTU: |
227 | /* |
228 | * We may not have a BIO set yet so can't call dtls1_min_mtu() |
229 | * We'll have to make do with dtls1_link_min_mtu() and max overhead |
230 | */ |
231 | if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD) |
232 | return 0; |
233 | s->d1->mtu = larg; |
234 | return larg; |
235 | default: |
236 | ret = ssl3_ctrl(s, cmd, larg, parg); |
237 | break; |
238 | } |
239 | return ret; |
240 | } |
241 | |
242 | void dtls1_start_timer(SSL *s) |
243 | { |
244 | unsigned int sec, usec; |
245 | |
246 | #ifndef OPENSSL_NO_SCTP |
247 | /* Disable timer for SCTP */ |
248 | if (BIO_dgram_is_sctp(SSL_get_wbio(s))) { |
249 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); |
250 | return; |
251 | } |
252 | #endif |
253 | |
254 | /* |
255 | * If timer is not set, initialize duration with 1 second or |
256 | * a user-specified value if the timer callback is installed. |
257 | */ |
258 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { |
259 | |
260 | if (s->d1->timer_cb != NULL) |
261 | s->d1->timeout_duration_us = s->d1->timer_cb(s, 0); |
262 | else |
263 | s->d1->timeout_duration_us = 1000000; |
264 | } |
265 | |
266 | /* Set timeout to current time */ |
267 | get_current_time(&(s->d1->next_timeout)); |
268 | |
269 | /* Add duration to current time */ |
270 | |
271 | sec = s->d1->timeout_duration_us / 1000000; |
272 | usec = s->d1->timeout_duration_us - (sec * 1000000); |
273 | |
274 | s->d1->next_timeout.tv_sec += sec; |
275 | s->d1->next_timeout.tv_usec += usec; |
276 | |
277 | if (s->d1->next_timeout.tv_usec >= 1000000) { |
278 | s->d1->next_timeout.tv_sec++; |
279 | s->d1->next_timeout.tv_usec -= 1000000; |
280 | } |
281 | |
282 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, |
283 | &(s->d1->next_timeout)); |
284 | } |
285 | |
286 | struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft) |
287 | { |
288 | struct timeval timenow; |
289 | |
290 | /* If no timeout is set, just return NULL */ |
291 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { |
292 | return NULL; |
293 | } |
294 | |
295 | /* Get current time */ |
296 | get_current_time(&timenow); |
297 | |
298 | /* If timer already expired, set remaining time to 0 */ |
299 | if (s->d1->next_timeout.tv_sec < timenow.tv_sec || |
300 | (s->d1->next_timeout.tv_sec == timenow.tv_sec && |
301 | s->d1->next_timeout.tv_usec <= timenow.tv_usec)) { |
302 | memset(timeleft, 0, sizeof(*timeleft)); |
303 | return timeleft; |
304 | } |
305 | |
306 | /* Calculate time left until timer expires */ |
307 | memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval)); |
308 | timeleft->tv_sec -= timenow.tv_sec; |
309 | timeleft->tv_usec -= timenow.tv_usec; |
310 | if (timeleft->tv_usec < 0) { |
311 | timeleft->tv_sec--; |
312 | timeleft->tv_usec += 1000000; |
313 | } |
314 | |
315 | /* |
316 | * If remaining time is less than 15 ms, set it to 0 to prevent issues |
317 | * because of small divergences with socket timeouts. |
318 | */ |
319 | if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) { |
320 | memset(timeleft, 0, sizeof(*timeleft)); |
321 | } |
322 | |
323 | return timeleft; |
324 | } |
325 | |
326 | int dtls1_is_timer_expired(SSL *s) |
327 | { |
328 | struct timeval timeleft; |
329 | |
330 | /* Get time left until timeout, return false if no timer running */ |
331 | if (dtls1_get_timeout(s, &timeleft) == NULL) { |
332 | return 0; |
333 | } |
334 | |
335 | /* Return false if timer is not expired yet */ |
336 | if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) { |
337 | return 0; |
338 | } |
339 | |
340 | /* Timer expired, so return true */ |
341 | return 1; |
342 | } |
343 | |
344 | void dtls1_double_timeout(SSL *s) |
345 | { |
346 | s->d1->timeout_duration_us *= 2; |
347 | if (s->d1->timeout_duration_us > 60000000) |
348 | s->d1->timeout_duration_us = 60000000; |
349 | dtls1_start_timer(s); |
350 | } |
351 | |
352 | void dtls1_stop_timer(SSL *s) |
353 | { |
354 | /* Reset everything */ |
355 | memset(&s->d1->timeout, 0, sizeof(s->d1->timeout)); |
356 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); |
357 | s->d1->timeout_duration_us = 1000000; |
358 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, |
359 | &(s->d1->next_timeout)); |
360 | /* Clear retransmission buffer */ |
361 | dtls1_clear_sent_buffer(s); |
362 | } |
363 | |
364 | int dtls1_check_timeout_num(SSL *s) |
365 | { |
366 | size_t mtu; |
367 | |
368 | s->d1->timeout.num_alerts++; |
369 | |
370 | /* Reduce MTU after 2 unsuccessful retransmissions */ |
371 | if (s->d1->timeout.num_alerts > 2 |
372 | && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { |
373 | mtu = |
374 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); |
375 | if (mtu < s->d1->mtu) |
376 | s->d1->mtu = mtu; |
377 | } |
378 | |
379 | if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) { |
380 | /* fail the connection, enough alerts have been sent */ |
381 | SSLfatal(s, SSL_AD_NO_ALERT, 0, |
382 | SSL_R_READ_TIMEOUT_EXPIRED); |
383 | return -1; |
384 | } |
385 | |
386 | return 0; |
387 | } |
388 | |
389 | int dtls1_handle_timeout(SSL *s) |
390 | { |
391 | /* if no timer is expired, don't do anything */ |
392 | if (!dtls1_is_timer_expired(s)) { |
393 | return 0; |
394 | } |
395 | |
396 | if (s->d1->timer_cb != NULL) |
397 | s->d1->timeout_duration_us = s->d1->timer_cb(s, s->d1->timeout_duration_us); |
398 | else |
399 | dtls1_double_timeout(s); |
400 | |
401 | if (dtls1_check_timeout_num(s) < 0) { |
402 | /* SSLfatal() already called */ |
403 | return -1; |
404 | } |
405 | |
406 | s->d1->timeout.read_timeouts++; |
407 | if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) { |
408 | s->d1->timeout.read_timeouts = 1; |
409 | } |
410 | |
411 | dtls1_start_timer(s); |
412 | /* Calls SSLfatal() if required */ |
413 | return dtls1_retransmit_buffered_messages(s); |
414 | } |
415 | |
416 | static void get_current_time(struct timeval *t) |
417 | { |
418 | #if defined(_WIN32) |
419 | SYSTEMTIME st; |
420 | union { |
421 | unsigned __int64 ul; |
422 | FILETIME ft; |
423 | } now; |
424 | |
425 | GetSystemTime(&st); |
426 | SystemTimeToFileTime(&st, &now.ft); |
427 | /* re-bias to 1/1/1970 */ |
428 | # ifdef __MINGW32__ |
429 | now.ul -= 116444736000000000ULL; |
430 | # else |
431 | /* *INDENT-OFF* */ |
432 | now.ul -= 116444736000000000UI64; |
433 | /* *INDENT-ON* */ |
434 | # endif |
435 | t->tv_sec = (long)(now.ul / 10000000); |
436 | t->tv_usec = ((int)(now.ul % 10000000)) / 10; |
437 | #else |
438 | gettimeofday(t, NULL); |
439 | #endif |
440 | } |
441 | |
442 | #define LISTEN_SUCCESS 2 |
443 | #define LISTEN_SEND_VERIFY_REQUEST 1 |
444 | |
445 | #ifndef OPENSSL_NO_SOCK |
446 | int DTLSv1_listen(SSL *s, BIO_ADDR *client) |
447 | { |
448 | int next, n, ret = 0; |
449 | unsigned char cookie[DTLS1_COOKIE_LENGTH]; |
450 | unsigned char seq[SEQ_NUM_SIZE]; |
451 | const unsigned char *data; |
452 | unsigned char *buf, *wbuf; |
453 | size_t fragoff, fraglen, msglen, reclen, align = 0; |
454 | unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen; |
455 | BIO *rbio, *wbio; |
456 | BIO_ADDR *tmpclient = NULL; |
457 | PACKET pkt, msgpkt, msgpayload, session, cookiepkt; |
458 | |
459 | if (s->handshake_func == NULL) { |
460 | /* Not properly initialized yet */ |
461 | SSL_set_accept_state(s); |
462 | } |
463 | |
464 | /* Ensure there is no state left over from a previous invocation */ |
465 | if (!SSL_clear(s)) |
466 | return -1; |
467 | |
468 | ERR_clear_error(); |
469 | |
470 | rbio = SSL_get_rbio(s); |
471 | wbio = SSL_get_wbio(s); |
472 | |
473 | if (!rbio || !wbio) { |
474 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET); |
475 | return -1; |
476 | } |
477 | |
478 | /* |
479 | * Note: This check deliberately excludes DTLS1_BAD_VER because that version |
480 | * requires the MAC to be calculated *including* the first ClientHello |
481 | * (without the cookie). Since DTLSv1_listen is stateless that cannot be |
482 | * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via |
483 | * SSL_accept) |
484 | */ |
485 | if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) { |
486 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION); |
487 | return -1; |
488 | } |
489 | |
490 | if (!ssl3_setup_buffers(s)) { |
491 | /* SSLerr already called */ |
492 | return -1; |
493 | } |
494 | buf = RECORD_LAYER_get_rbuf(&s->rlayer)->buf; |
495 | wbuf = RECORD_LAYER_get_wbuf(&s->rlayer)[0].buf; |
496 | #if defined(SSL3_ALIGN_PAYLOAD) |
497 | # if SSL3_ALIGN_PAYLOAD != 0 |
498 | /* |
499 | * Using SSL3_RT_HEADER_LENGTH here instead of DTLS1_RT_HEADER_LENGTH for |
500 | * consistency with ssl3_read_n. In practice it should make no difference |
501 | * for sensible values of SSL3_ALIGN_PAYLOAD because the difference between |
502 | * SSL3_RT_HEADER_LENGTH and DTLS1_RT_HEADER_LENGTH is exactly 8 |
503 | */ |
504 | align = (size_t)buf + SSL3_RT_HEADER_LENGTH; |
505 | align = SSL3_ALIGN_PAYLOAD - 1 - ((align - 1) % SSL3_ALIGN_PAYLOAD); |
506 | # endif |
507 | #endif |
508 | buf += align; |
509 | |
510 | do { |
511 | /* Get a packet */ |
512 | |
513 | clear_sys_error(); |
514 | n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH |
515 | + DTLS1_RT_HEADER_LENGTH); |
516 | if (n <= 0) { |
517 | if (BIO_should_retry(rbio)) { |
518 | /* Non-blocking IO */ |
519 | goto end; |
520 | } |
521 | return -1; |
522 | } |
523 | |
524 | if (!PACKET_buf_init(&pkt, buf, n)) { |
525 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); |
526 | return -1; |
527 | } |
528 | |
529 | /* |
530 | * Parse the received record. If there are any problems with it we just |
531 | * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is |
532 | * resilient in the face of invalid records (e.g., invalid formatting, |
533 | * length, MAC, etc.). In general, invalid records SHOULD be silently |
534 | * discarded, thus preserving the association; however, an error MAY be |
535 | * logged for diagnostic purposes." |
536 | */ |
537 | |
538 | /* this packet contained a partial record, dump it */ |
539 | if (n < DTLS1_RT_HEADER_LENGTH) { |
540 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL); |
541 | goto end; |
542 | } |
543 | |
544 | if (s->msg_callback) |
545 | s->msg_callback(0, 0, SSL3_RT_HEADER, buf, |
546 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); |
547 | |
548 | /* Get the record header */ |
549 | if (!PACKET_get_1(&pkt, &rectype) |
550 | || !PACKET_get_1(&pkt, &versmajor)) { |
551 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
552 | goto end; |
553 | } |
554 | |
555 | if (rectype != SSL3_RT_HANDSHAKE) { |
556 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
557 | goto end; |
558 | } |
559 | |
560 | /* |
561 | * Check record version number. We only check that the major version is |
562 | * the same. |
563 | */ |
564 | if (versmajor != DTLS1_VERSION_MAJOR) { |
565 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); |
566 | goto end; |
567 | } |
568 | |
569 | if (!PACKET_forward(&pkt, 1) |
570 | /* Save the sequence number: 64 bits, with top 2 bytes = epoch */ |
571 | || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE) |
572 | || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) { |
573 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
574 | goto end; |
575 | } |
576 | reclen = PACKET_remaining(&msgpkt); |
577 | /* |
578 | * We allow data remaining at the end of the packet because there could |
579 | * be a second record (but we ignore it) |
580 | */ |
581 | |
582 | /* This is an initial ClientHello so the epoch has to be 0 */ |
583 | if (seq[0] != 0 || seq[1] != 0) { |
584 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
585 | goto end; |
586 | } |
587 | |
588 | /* Get a pointer to the raw message for the later callback */ |
589 | data = PACKET_data(&msgpkt); |
590 | |
591 | /* Finished processing the record header, now process the message */ |
592 | if (!PACKET_get_1(&msgpkt, &msgtype) |
593 | || !PACKET_get_net_3_len(&msgpkt, &msglen) |
594 | || !PACKET_get_net_2(&msgpkt, &msgseq) |
595 | || !PACKET_get_net_3_len(&msgpkt, &fragoff) |
596 | || !PACKET_get_net_3_len(&msgpkt, &fraglen) |
597 | || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen) |
598 | || PACKET_remaining(&msgpkt) != 0) { |
599 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
600 | goto end; |
601 | } |
602 | |
603 | if (msgtype != SSL3_MT_CLIENT_HELLO) { |
604 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
605 | goto end; |
606 | } |
607 | |
608 | /* Message sequence number can only be 0 or 1 */ |
609 | if (msgseq > 2) { |
610 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER); |
611 | goto end; |
612 | } |
613 | |
614 | /* |
615 | * We don't support fragment reassembly for ClientHellos whilst |
616 | * listening because that would require server side state (which is |
617 | * against the whole point of the ClientHello/HelloVerifyRequest |
618 | * mechanism). Instead we only look at the first ClientHello fragment |
619 | * and require that the cookie must be contained within it. |
620 | */ |
621 | if (fragoff != 0 || fraglen > msglen) { |
622 | /* Non initial ClientHello fragment (or bad fragment) */ |
623 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO); |
624 | goto end; |
625 | } |
626 | |
627 | if (s->msg_callback) |
628 | s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data, |
629 | fraglen + DTLS1_HM_HEADER_LENGTH, s, |
630 | s->msg_callback_arg); |
631 | |
632 | if (!PACKET_get_net_2(&msgpayload, &clientvers)) { |
633 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
634 | goto end; |
635 | } |
636 | |
637 | /* |
638 | * Verify client version is supported |
639 | */ |
640 | if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) && |
641 | s->method->version != DTLS_ANY_VERSION) { |
642 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER); |
643 | goto end; |
644 | } |
645 | |
646 | if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE) |
647 | || !PACKET_get_length_prefixed_1(&msgpayload, &session) |
648 | || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) { |
649 | /* |
650 | * Could be malformed or the cookie does not fit within the initial |
651 | * ClientHello fragment. Either way we can't handle it. |
652 | */ |
653 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
654 | goto end; |
655 | } |
656 | |
657 | /* |
658 | * Check if we have a cookie or not. If not we need to send a |
659 | * HelloVerifyRequest. |
660 | */ |
661 | if (PACKET_remaining(&cookiepkt) == 0) { |
662 | next = LISTEN_SEND_VERIFY_REQUEST; |
663 | } else { |
664 | /* |
665 | * We have a cookie, so lets check it. |
666 | */ |
667 | if (s->ctx->app_verify_cookie_cb == NULL) { |
668 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK); |
669 | /* This is fatal */ |
670 | return -1; |
671 | } |
672 | if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt), |
673 | (unsigned int)PACKET_remaining(&cookiepkt)) == 0) { |
674 | /* |
675 | * We treat invalid cookies in the same was as no cookie as |
676 | * per RFC6347 |
677 | */ |
678 | next = LISTEN_SEND_VERIFY_REQUEST; |
679 | } else { |
680 | /* Cookie verification succeeded */ |
681 | next = LISTEN_SUCCESS; |
682 | } |
683 | } |
684 | |
685 | if (next == LISTEN_SEND_VERIFY_REQUEST) { |
686 | WPACKET wpkt; |
687 | unsigned int version; |
688 | size_t wreclen; |
689 | |
690 | /* |
691 | * There was no cookie in the ClientHello so we need to send a |
692 | * HelloVerifyRequest. If this fails we do not worry about trying |
693 | * to resend, we just drop it. |
694 | */ |
695 | |
696 | /* Generate the cookie */ |
697 | if (s->ctx->app_gen_cookie_cb == NULL || |
698 | s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 || |
699 | cookielen > 255) { |
700 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE); |
701 | /* This is fatal */ |
702 | return -1; |
703 | } |
704 | |
705 | /* |
706 | * Special case: for hello verify request, client version 1.0 and we |
707 | * haven't decided which version to use yet send back using version |
708 | * 1.0 header: otherwise some clients will ignore it. |
709 | */ |
710 | version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION |
711 | : s->version; |
712 | |
713 | /* Construct the record and message headers */ |
714 | if (!WPACKET_init_static_len(&wpkt, |
715 | wbuf, |
716 | ssl_get_max_send_fragment(s) |
717 | + DTLS1_RT_HEADER_LENGTH, |
718 | 0) |
719 | || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE) |
720 | || !WPACKET_put_bytes_u16(&wpkt, version) |
721 | /* |
722 | * Record sequence number is always the same as in the |
723 | * received ClientHello |
724 | */ |
725 | || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE) |
726 | /* End of record, start sub packet for message */ |
727 | || !WPACKET_start_sub_packet_u16(&wpkt) |
728 | /* Message type */ |
729 | || !WPACKET_put_bytes_u8(&wpkt, |
730 | DTLS1_MT_HELLO_VERIFY_REQUEST) |
731 | /* |
732 | * Message length - doesn't follow normal TLS convention: |
733 | * the length isn't the last thing in the message header. |
734 | * We'll need to fill this in later when we know the |
735 | * length. Set it to zero for now |
736 | */ |
737 | || !WPACKET_put_bytes_u24(&wpkt, 0) |
738 | /* |
739 | * Message sequence number is always 0 for a |
740 | * HelloVerifyRequest |
741 | */ |
742 | || !WPACKET_put_bytes_u16(&wpkt, 0) |
743 | /* |
744 | * We never fragment a HelloVerifyRequest, so fragment |
745 | * offset is 0 |
746 | */ |
747 | || !WPACKET_put_bytes_u24(&wpkt, 0) |
748 | /* |
749 | * Fragment length is the same as message length, but |
750 | * this *is* the last thing in the message header so we |
751 | * can just start a sub-packet. No need to come back |
752 | * later for this one. |
753 | */ |
754 | || !WPACKET_start_sub_packet_u24(&wpkt) |
755 | /* Create the actual HelloVerifyRequest body */ |
756 | || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen) |
757 | /* Close message body */ |
758 | || !WPACKET_close(&wpkt) |
759 | /* Close record body */ |
760 | || !WPACKET_close(&wpkt) |
761 | || !WPACKET_get_total_written(&wpkt, &wreclen) |
762 | || !WPACKET_finish(&wpkt)) { |
763 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); |
764 | WPACKET_cleanup(&wpkt); |
765 | /* This is fatal */ |
766 | return -1; |
767 | } |
768 | |
769 | /* |
770 | * Fix up the message len in the message header. Its the same as the |
771 | * fragment len which has been filled in by WPACKET, so just copy |
772 | * that. Destination for the message len is after the record header |
773 | * plus one byte for the message content type. The source is the |
774 | * last 3 bytes of the message header |
775 | */ |
776 | memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1], |
777 | &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3], |
778 | 3); |
779 | |
780 | if (s->msg_callback) |
781 | s->msg_callback(1, 0, SSL3_RT_HEADER, buf, |
782 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); |
783 | |
784 | if ((tmpclient = BIO_ADDR_new()) == NULL) { |
785 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE); |
786 | goto end; |
787 | } |
788 | |
789 | /* |
790 | * This is unnecessary if rbio and wbio are one and the same - but |
791 | * maybe they're not. We ignore errors here - some BIOs do not |
792 | * support this. |
793 | */ |
794 | if (BIO_dgram_get_peer(rbio, tmpclient) > 0) { |
795 | (void)BIO_dgram_set_peer(wbio, tmpclient); |
796 | } |
797 | BIO_ADDR_free(tmpclient); |
798 | tmpclient = NULL; |
799 | |
800 | /* TODO(size_t): convert this call */ |
801 | if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) { |
802 | if (BIO_should_retry(wbio)) { |
803 | /* |
804 | * Non-blocking IO...but we're stateless, so we're just |
805 | * going to drop this packet. |
806 | */ |
807 | goto end; |
808 | } |
809 | return -1; |
810 | } |
811 | |
812 | if (BIO_flush(wbio) <= 0) { |
813 | if (BIO_should_retry(wbio)) { |
814 | /* |
815 | * Non-blocking IO...but we're stateless, so we're just |
816 | * going to drop this packet. |
817 | */ |
818 | goto end; |
819 | } |
820 | return -1; |
821 | } |
822 | } |
823 | } while (next != LISTEN_SUCCESS); |
824 | |
825 | /* |
826 | * Set expected sequence numbers to continue the handshake. |
827 | */ |
828 | s->d1->handshake_read_seq = 1; |
829 | s->d1->handshake_write_seq = 1; |
830 | s->d1->next_handshake_write_seq = 1; |
831 | DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq); |
832 | |
833 | /* |
834 | * We are doing cookie exchange, so make sure we set that option in the |
835 | * SSL object |
836 | */ |
837 | SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); |
838 | |
839 | /* |
840 | * Tell the state machine that we've done the initial hello verify |
841 | * exchange |
842 | */ |
843 | ossl_statem_set_hello_verify_done(s); |
844 | |
845 | /* |
846 | * Some BIOs may not support this. If we fail we clear the client address |
847 | */ |
848 | if (BIO_dgram_get_peer(rbio, client) <= 0) |
849 | BIO_ADDR_clear(client); |
850 | |
851 | /* Buffer the record in the processed_rcds queue */ |
852 | if (!dtls_buffer_listen_record(s, reclen, seq, align)) |
853 | return -1; |
854 | |
855 | ret = 1; |
856 | end: |
857 | BIO_ADDR_free(tmpclient); |
858 | return ret; |
859 | } |
860 | #endif |
861 | |
862 | static int dtls1_handshake_write(SSL *s) |
863 | { |
864 | return dtls1_do_write(s, SSL3_RT_HANDSHAKE); |
865 | } |
866 | |
867 | int dtls1_shutdown(SSL *s) |
868 | { |
869 | int ret; |
870 | #ifndef OPENSSL_NO_SCTP |
871 | BIO *wbio; |
872 | |
873 | wbio = SSL_get_wbio(s); |
874 | if (wbio != NULL && BIO_dgram_is_sctp(wbio) && |
875 | !(s->shutdown & SSL_SENT_SHUTDOWN)) { |
876 | ret = BIO_dgram_sctp_wait_for_dry(wbio); |
877 | if (ret < 0) |
878 | return -1; |
879 | |
880 | if (ret == 0) |
881 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, |
882 | NULL); |
883 | } |
884 | #endif |
885 | ret = ssl3_shutdown(s); |
886 | #ifndef OPENSSL_NO_SCTP |
887 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL); |
888 | #endif |
889 | return ret; |
890 | } |
891 | |
892 | int dtls1_query_mtu(SSL *s) |
893 | { |
894 | if (s->d1->link_mtu) { |
895 | s->d1->mtu = |
896 | s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); |
897 | s->d1->link_mtu = 0; |
898 | } |
899 | |
900 | /* AHA! Figure out the MTU, and stick to the right size */ |
901 | if (s->d1->mtu < dtls1_min_mtu(s)) { |
902 | if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { |
903 | s->d1->mtu = |
904 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); |
905 | |
906 | /* |
907 | * I've seen the kernel return bogus numbers when it doesn't know |
908 | * (initial write), so just make sure we have a reasonable number |
909 | */ |
910 | if (s->d1->mtu < dtls1_min_mtu(s)) { |
911 | /* Set to min mtu */ |
912 | s->d1->mtu = dtls1_min_mtu(s); |
913 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, |
914 | (long)s->d1->mtu, NULL); |
915 | } |
916 | } else |
917 | return 0; |
918 | } |
919 | return 1; |
920 | } |
921 | |
922 | static size_t dtls1_link_min_mtu(void) |
923 | { |
924 | return (g_probable_mtu[(sizeof(g_probable_mtu) / |
925 | sizeof(g_probable_mtu[0])) - 1]); |
926 | } |
927 | |
928 | size_t dtls1_min_mtu(SSL *s) |
929 | { |
930 | return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); |
931 | } |
932 | |
933 | size_t DTLS_get_data_mtu(const SSL *s) |
934 | { |
935 | size_t mac_overhead, int_overhead, blocksize, ext_overhead; |
936 | const SSL_CIPHER *ciph = SSL_get_current_cipher(s); |
937 | size_t mtu = s->d1->mtu; |
938 | |
939 | if (ciph == NULL) |
940 | return 0; |
941 | |
942 | if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead, |
943 | &blocksize, &ext_overhead)) |
944 | return 0; |
945 | |
946 | if (SSL_READ_ETM(s)) |
947 | ext_overhead += mac_overhead; |
948 | else |
949 | int_overhead += mac_overhead; |
950 | |
951 | /* Subtract external overhead (e.g. IV/nonce, separate MAC) */ |
952 | if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu) |
953 | return 0; |
954 | mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH; |
955 | |
956 | /* Round encrypted payload down to cipher block size (for CBC etc.) |
957 | * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */ |
958 | if (blocksize) |
959 | mtu -= (mtu % blocksize); |
960 | |
961 | /* Subtract internal overhead (e.g. CBC padding len byte) */ |
962 | if (int_overhead >= mtu) |
963 | return 0; |
964 | mtu -= int_overhead; |
965 | |
966 | return mtu; |
967 | } |
968 | |
969 | void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb) |
970 | { |
971 | s->d1->timer_cb = cb; |
972 | } |
973 | |