xref: /dragonfly/crypto/libressl/ssl/d1_lib.c (revision 07ed7d32) 
1 /* $OpenBSD: d1_lib.c,v 1.32 2015/10/07 13:20:48 bcook Exp $ */
2 /*
3  * DTLS implementation written by Nagendra Modadugu
4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5  */
6 /* ====================================================================
7  * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in
18  *    the documentation and/or other materials provided with the
19  *    distribution.
20  *
21  * 3. All advertising materials mentioning features or use of this
22  *    software must display the following acknowledgment:
23  *    "This product includes software developed by the OpenSSL Project
24  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25  *
26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27  *    endorse or promote products derived from this software without
28  *    prior written permission. For written permission, please contact
29  *    openssl-core@OpenSSL.org.
30  *
31  * 5. Products derived from this software may not be called "OpenSSL"
32  *    nor may "OpenSSL" appear in their names without prior written
33  *    permission of the OpenSSL Project.
34  *
35  * 6. Redistributions of any form whatsoever must retain the following
36  *    acknowledgment:
37  *    "This product includes software developed by the OpenSSL Project
38  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51  * OF THE POSSIBILITY OF SUCH DAMAGE.
52  * ====================================================================
53  *
54  * This product includes cryptographic software written by Eric Young
55  * (eay@cryptsoft.com).  This product includes software written by Tim
56  * Hudson (tjh@cryptsoft.com).
57  *
58  */
59 
60 #include <sys/types.h>
61 #include <sys/socket.h>
62 #include <sys/time.h>
63 
64 #include <netinet/in.h>
65 
66 #include <stdio.h>
67 
68 #include <openssl/objects.h>
69 
70 #include "pqueue.h"
71 #include "ssl_locl.h"
72 
73 int dtls1_listen(SSL *s, struct sockaddr *client);
74 
75 SSL3_ENC_METHOD DTLSv1_enc_data = {
76 	.enc = dtls1_enc,
77 	.mac = tls1_mac,
78 	.setup_key_block = tls1_setup_key_block,
79 	.generate_master_secret = tls1_generate_master_secret,
80 	.change_cipher_state = tls1_change_cipher_state,
81 	.final_finish_mac = tls1_final_finish_mac,
82 	.finish_mac_length = TLS1_FINISH_MAC_LENGTH,
83 	.cert_verify_mac = tls1_cert_verify_mac,
84 	.client_finished_label = TLS_MD_CLIENT_FINISH_CONST,
85 	.client_finished_label_len = TLS_MD_CLIENT_FINISH_CONST_SIZE,
86 	.server_finished_label = TLS_MD_SERVER_FINISH_CONST,
87 	.server_finished_label_len = TLS_MD_SERVER_FINISH_CONST_SIZE,
88 	.alert_value = tls1_alert_code,
89 	.export_keying_material = tls1_export_keying_material,
90 	.enc_flags = SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV,
91 };
92 
93 long
94 dtls1_default_timeout(void)
95 {
96 	/* 2 hours, the 24 hours mentioned in the DTLSv1 spec
97 	 * is way too long for http, the cache would over fill */
98 	return (60*60*2);
99 }
100 
101 int
102 dtls1_new(SSL *s)
103 {
104 	DTLS1_STATE *d1;
105 
106 	if (!ssl3_new(s))
107 		return (0);
108 	if ((d1 = calloc(1, sizeof *d1)) == NULL) {
109 		ssl3_free(s);
110 		return (0);
111 	}
112 
113 	/* d1->handshake_epoch=0; */
114 
115 	d1->unprocessed_rcds.q = pqueue_new();
116 	d1->processed_rcds.q = pqueue_new();
117 	d1->buffered_messages = pqueue_new();
118 	d1->sent_messages = pqueue_new();
119 	d1->buffered_app_data.q = pqueue_new();
120 
121 	if (s->server) {
122 		d1->cookie_len = sizeof(s->d1->cookie);
123 	}
124 
125 	if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q ||
126 	    !d1->buffered_messages || !d1->sent_messages ||
127 	    !d1->buffered_app_data.q) {
128 		pqueue_free(d1->unprocessed_rcds.q);
129 		pqueue_free(d1->processed_rcds.q);
130 		pqueue_free(d1->buffered_messages);
131 		pqueue_free(d1->sent_messages);
132 		pqueue_free(d1->buffered_app_data.q);
133 		free(d1);
134 		ssl3_free(s);
135 		return (0);
136 	}
137 
138 	s->d1 = d1;
139 	s->method->ssl_clear(s);
140 	return (1);
141 }
142 
143 static void
144 dtls1_clear_queues(SSL *s)
145 {
146 	pitem *item = NULL;
147 	hm_fragment *frag = NULL;
148 	DTLS1_RECORD_DATA *rdata;
149 
150 	while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) {
151 		rdata = (DTLS1_RECORD_DATA *) item->data;
152 		free(rdata->rbuf.buf);
153 		free(item->data);
154 		pitem_free(item);
155 	}
156 
157 	while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
158 		rdata = (DTLS1_RECORD_DATA *) item->data;
159 		free(rdata->rbuf.buf);
160 		free(item->data);
161 		pitem_free(item);
162 	}
163 
164 	while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
165 		frag = (hm_fragment *)item->data;
166 		free(frag->fragment);
167 		free(frag);
168 		pitem_free(item);
169 	}
170 
171 	while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
172 		frag = (hm_fragment *)item->data;
173 		free(frag->fragment);
174 		free(frag);
175 		pitem_free(item);
176 	}
177 
178 	while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) {
179 		rdata = (DTLS1_RECORD_DATA *) item->data;
180 		free(rdata->rbuf.buf);
181 		free(item->data);
182 		pitem_free(item);
183 	}
184 }
185 
186 void
187 dtls1_free(SSL *s)
188 {
189 	if (s == NULL)
190 		return;
191 
192 	ssl3_free(s);
193 
194 	dtls1_clear_queues(s);
195 
196 	pqueue_free(s->d1->unprocessed_rcds.q);
197 	pqueue_free(s->d1->processed_rcds.q);
198 	pqueue_free(s->d1->buffered_messages);
199 	pqueue_free(s->d1->sent_messages);
200 	pqueue_free(s->d1->buffered_app_data.q);
201 
202 	explicit_bzero(s->d1, sizeof *s->d1);
203 	free(s->d1);
204 	s->d1 = NULL;
205 }
206 
207 void
208 dtls1_clear(SSL *s)
209 {
210 	pqueue unprocessed_rcds;
211 	pqueue processed_rcds;
212 	pqueue buffered_messages;
213 	pqueue sent_messages;
214 	pqueue buffered_app_data;
215 	unsigned int mtu;
216 
217 	if (s->d1) {
218 		unprocessed_rcds = s->d1->unprocessed_rcds.q;
219 		processed_rcds = s->d1->processed_rcds.q;
220 		buffered_messages = s->d1->buffered_messages;
221 		sent_messages = s->d1->sent_messages;
222 		buffered_app_data = s->d1->buffered_app_data.q;
223 		mtu = s->d1->mtu;
224 
225 		dtls1_clear_queues(s);
226 
227 		memset(s->d1, 0, sizeof(*(s->d1)));
228 
229 		if (s->server) {
230 			s->d1->cookie_len = sizeof(s->d1->cookie);
231 		}
232 
233 		if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
234 			s->d1->mtu = mtu;
235 		}
236 
237 		s->d1->unprocessed_rcds.q = unprocessed_rcds;
238 		s->d1->processed_rcds.q = processed_rcds;
239 		s->d1->buffered_messages = buffered_messages;
240 		s->d1->sent_messages = sent_messages;
241 		s->d1->buffered_app_data.q = buffered_app_data;
242 	}
243 
244 	ssl3_clear(s);
245 
246 	s->version = DTLS1_VERSION;
247 }
248 
249 long
250 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
251 {
252 	int ret = 0;
253 
254 	switch (cmd) {
255 	case DTLS_CTRL_GET_TIMEOUT:
256 		if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) {
257 			ret = 1;
258 		}
259 		break;
260 	case DTLS_CTRL_HANDLE_TIMEOUT:
261 		ret = dtls1_handle_timeout(s);
262 		break;
263 	case DTLS_CTRL_LISTEN:
264 		ret = dtls1_listen(s, parg);
265 		break;
266 
267 	default:
268 		ret = ssl3_ctrl(s, cmd, larg, parg);
269 		break;
270 	}
271 	return (ret);
272 }
273 
274 /*
275  * As it's impossible to use stream ciphers in "datagram" mode, this
276  * simple filter is designed to disengage them in DTLS. Unfortunately
277  * there is no universal way to identify stream SSL_CIPHER, so we have
278  * to explicitly list their SSL_* codes. Currently RC4 is the only one
279  * available, but if new ones emerge, they will have to be added...
280  */
281 const SSL_CIPHER *
282 dtls1_get_cipher(unsigned int u)
283 {
284 	const SSL_CIPHER *ciph = ssl3_get_cipher(u);
285 
286 	if (ciph != NULL) {
287 		if (ciph->algorithm_enc == SSL_RC4)
288 			return NULL;
289 	}
290 
291 	return ciph;
292 }
293 
294 void
295 dtls1_start_timer(SSL *s)
296 {
297 
298 	/* If timer is not set, initialize duration with 1 second */
299 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
300 		s->d1->timeout_duration = 1;
301 	}
302 
303 	/* Set timeout to current time */
304 	gettimeofday(&(s->d1->next_timeout), NULL);
305 
306 	/* Add duration to current time */
307 	s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
308 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
309 	    &(s->d1->next_timeout));
310 }
311 
312 struct timeval*
313 dtls1_get_timeout(SSL *s, struct timeval* timeleft)
314 {
315 	struct timeval timenow;
316 
317 	/* If no timeout is set, just return NULL */
318 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
319 		return NULL;
320 	}
321 
322 	/* Get current time */
323 	gettimeofday(&timenow, NULL);
324 
325 	/* If timer already expired, set remaining time to 0 */
326 	if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
327 	    (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
328 	     s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
329 		memset(timeleft, 0, sizeof(struct timeval));
330 		return timeleft;
331 	}
332 
333 	/* Calculate time left until timer expires */
334 	memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
335 	timeleft->tv_sec -= timenow.tv_sec;
336 	timeleft->tv_usec -= timenow.tv_usec;
337 	if (timeleft->tv_usec < 0) {
338 		timeleft->tv_sec--;
339 		timeleft->tv_usec += 1000000;
340 	}
341 
342 	/* If remaining time is less than 15 ms, set it to 0
343 	 * to prevent issues because of small devergences with
344 	 * socket timeouts.
345 	 */
346 	if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
347 		memset(timeleft, 0, sizeof(struct timeval));
348 	}
349 
350 
351 	return timeleft;
352 }
353 
354 int
355 dtls1_is_timer_expired(SSL *s)
356 {
357 	struct timeval timeleft;
358 
359 	/* Get time left until timeout, return false if no timer running */
360 	if (dtls1_get_timeout(s, &timeleft) == NULL) {
361 		return 0;
362 	}
363 
364 	/* Return false if timer is not expired yet */
365 	if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
366 		return 0;
367 	}
368 
369 	/* Timer expired, so return true */
370 	return 1;
371 }
372 
373 void
374 dtls1_double_timeout(SSL *s)
375 {
376 	s->d1->timeout_duration *= 2;
377 	if (s->d1->timeout_duration > 60)
378 		s->d1->timeout_duration = 60;
379 	dtls1_start_timer(s);
380 }
381 
382 void
383 dtls1_stop_timer(SSL *s)
384 {
385 	/* Reset everything */
386 	memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
387 	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
388 	s->d1->timeout_duration = 1;
389 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
390 	    &(s->d1->next_timeout));
391 	/* Clear retransmission buffer */
392 	dtls1_clear_record_buffer(s);
393 }
394 
395 int
396 dtls1_check_timeout_num(SSL *s)
397 {
398 	s->d1->timeout.num_alerts++;
399 
400 	/* Reduce MTU after 2 unsuccessful retransmissions */
401 	if (s->d1->timeout.num_alerts > 2) {
402 		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
403 		    BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
404 
405 	}
406 
407 	if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
408 		/* fail the connection, enough alerts have been sent */
409 		SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
410 		return -1;
411 	}
412 
413 	return 0;
414 }
415 
416 int
417 dtls1_handle_timeout(SSL *s)
418 {
419 	/* if no timer is expired, don't do anything */
420 	if (!dtls1_is_timer_expired(s)) {
421 		return 0;
422 	}
423 
424 	dtls1_double_timeout(s);
425 
426 	if (dtls1_check_timeout_num(s) < 0)
427 		return -1;
428 
429 	s->d1->timeout.read_timeouts++;
430 	if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
431 		s->d1->timeout.read_timeouts = 1;
432 	}
433 
434 	dtls1_start_timer(s);
435 	return dtls1_retransmit_buffered_messages(s);
436 }
437 
438 int
439 dtls1_listen(SSL *s, struct sockaddr *client)
440 {
441 	int ret;
442 
443 	/* Ensure there is no state left over from a previous invocation */
444 	SSL_clear(s);
445 
446 	SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
447 	s->d1->listen = 1;
448 
449 	ret = SSL_accept(s);
450 	if (ret <= 0)
451 		return ret;
452 
453 	(void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
454 	return 1;
455 }
456 
457 void
458 dtls1_build_sequence_number(unsigned char *dst, unsigned char *seq,
459     unsigned short epoch)
460 {
461 	unsigned char dtlsseq[SSL3_SEQUENCE_SIZE];
462 	unsigned char *p;
463 
464 	p = dtlsseq;
465 	s2n(epoch, p);
466 	memcpy(p, &seq[2], SSL3_SEQUENCE_SIZE - 2);
467 	memcpy(dst, dtlsseq, SSL3_SEQUENCE_SIZE);
468 }
469