xref: /openbsd/lib/libssl/d1_lib.c (revision d415bd75) 
1 /* $OpenBSD: d1_lib.c,v 1.64 2022/11/26 16:08:55 tb 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 "dtls_local.h"
71 #include "pqueue.h"
72 #include "ssl_local.h"
73 
74 void dtls1_hm_fragment_free(hm_fragment *frag);
75 
76 static int dtls1_listen(SSL *s, struct sockaddr *client);
77 
78 int
79 dtls1_new(SSL *s)
80 {
81 	if (!ssl3_new(s))
82 		goto err;
83 
84 	if ((s->d1 = calloc(1, sizeof(*s->d1))) == NULL)
85 		goto err;
86 
87 	if ((s->d1->unprocessed_rcds.q = pqueue_new()) == NULL)
88 		goto err;
89 	if ((s->d1->buffered_messages = pqueue_new()) == NULL)
90 		goto err;
91 	if ((s->d1->sent_messages = pqueue_new()) == NULL)
92 		goto err;
93 	if ((s->d1->buffered_app_data.q = pqueue_new()) == NULL)
94 		goto err;
95 
96 	if (s->server)
97 		s->d1->cookie_len = sizeof(s->d1->cookie);
98 
99 	s->method->ssl_clear(s);
100 	return (1);
101 
102  err:
103 	dtls1_free(s);
104 	return (0);
105 }
106 
107 static void
108 dtls1_drain_rcontents(pqueue queue)
109 {
110 	DTLS1_RCONTENT_DATA_INTERNAL *rdata;
111 	pitem *item;
112 
113 	if (queue == NULL)
114 		return;
115 
116 	while ((item = pqueue_pop(queue)) != NULL) {
117 		rdata = (DTLS1_RCONTENT_DATA_INTERNAL *)item->data;
118 		tls_content_free(rdata->rcontent);
119 		free(item->data);
120 		pitem_free(item);
121 	}
122 }
123 
124 static void
125 dtls1_drain_records(pqueue queue)
126 {
127 	pitem *item;
128 	DTLS1_RECORD_DATA_INTERNAL *rdata;
129 
130 	if (queue == NULL)
131 		return;
132 
133 	while ((item = pqueue_pop(queue)) != NULL) {
134 		rdata = (DTLS1_RECORD_DATA_INTERNAL *)item->data;
135 		ssl3_release_buffer(&rdata->rbuf);
136 		free(item->data);
137 		pitem_free(item);
138 	}
139 }
140 
141 static void
142 dtls1_drain_fragments(pqueue queue)
143 {
144 	pitem *item;
145 
146 	if (queue == NULL)
147 		return;
148 
149 	while ((item = pqueue_pop(queue)) != NULL) {
150 		dtls1_hm_fragment_free(item->data);
151 		pitem_free(item);
152 	}
153 }
154 
155 static void
156 dtls1_clear_queues(SSL *s)
157 {
158 	dtls1_drain_records(s->d1->unprocessed_rcds.q);
159 	dtls1_drain_fragments(s->d1->buffered_messages);
160 	dtls1_drain_fragments(s->d1->sent_messages);
161 	dtls1_drain_rcontents(s->d1->buffered_app_data.q);
162 }
163 
164 void
165 dtls1_free(SSL *s)
166 {
167 	if (s == NULL)
168 		return;
169 
170 	ssl3_free(s);
171 
172 	if (s->d1 == NULL)
173 		return;
174 
175 	dtls1_clear_queues(s);
176 
177 	pqueue_free(s->d1->unprocessed_rcds.q);
178 	pqueue_free(s->d1->buffered_messages);
179 	pqueue_free(s->d1->sent_messages);
180 	pqueue_free(s->d1->buffered_app_data.q);
181 
182 	freezero(s->d1, sizeof(*s->d1));
183 	s->d1 = NULL;
184 }
185 
186 void
187 dtls1_clear(SSL *s)
188 {
189 	pqueue unprocessed_rcds;
190 	pqueue buffered_messages;
191 	pqueue sent_messages;
192 	pqueue buffered_app_data;
193 	unsigned int mtu;
194 
195 	if (s->d1) {
196 		unprocessed_rcds = s->d1->unprocessed_rcds.q;
197 		buffered_messages = s->d1->buffered_messages;
198 		sent_messages = s->d1->sent_messages;
199 		buffered_app_data = s->d1->buffered_app_data.q;
200 		mtu = s->d1->mtu;
201 
202 		dtls1_clear_queues(s);
203 
204 		memset(s->d1, 0, sizeof(*s->d1));
205 
206 		s->d1->unprocessed_rcds.epoch =
207 		    tls12_record_layer_read_epoch(s->rl) + 1;
208 
209 		if (s->server) {
210 			s->d1->cookie_len = sizeof(s->d1->cookie);
211 		}
212 
213 		if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
214 			s->d1->mtu = mtu;
215 		}
216 
217 		s->d1->unprocessed_rcds.q = unprocessed_rcds;
218 		s->d1->buffered_messages = buffered_messages;
219 		s->d1->sent_messages = sent_messages;
220 		s->d1->buffered_app_data.q = buffered_app_data;
221 	}
222 
223 	ssl3_clear(s);
224 
225 	s->version = DTLS1_VERSION;
226 }
227 
228 long
229 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
230 {
231 	int ret = 0;
232 
233 	switch (cmd) {
234 	case DTLS_CTRL_GET_TIMEOUT:
235 		if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) {
236 			ret = 1;
237 		}
238 		break;
239 	case DTLS_CTRL_HANDLE_TIMEOUT:
240 		ret = dtls1_handle_timeout(s);
241 		break;
242 	case DTLS_CTRL_LISTEN:
243 		ret = dtls1_listen(s, parg);
244 		break;
245 
246 	default:
247 		ret = ssl3_ctrl(s, cmd, larg, parg);
248 		break;
249 	}
250 	return (ret);
251 }
252 
253 /*
254  * As it's impossible to use stream ciphers in "datagram" mode, this
255  * simple filter is designed to disengage them in DTLS. Unfortunately
256  * there is no universal way to identify stream SSL_CIPHER, so we have
257  * to explicitly list their SSL_* codes. Currently RC4 is the only one
258  * available, but if new ones emerge, they will have to be added...
259  */
260 const SSL_CIPHER *
261 dtls1_get_cipher(unsigned int u)
262 {
263 	const SSL_CIPHER *cipher;
264 
265 	if ((cipher = ssl3_get_cipher(u)) == NULL)
266 		return NULL;
267 
268 	if (cipher->algorithm_enc == SSL_RC4)
269 		return NULL;
270 
271 	return cipher;
272 }
273 
274 void
275 dtls1_start_timer(SSL *s)
276 {
277 
278 	/* If timer is not set, initialize duration with 1 second */
279 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
280 		s->d1->timeout_duration = 1;
281 	}
282 
283 	/* Set timeout to current time */
284 	gettimeofday(&(s->d1->next_timeout), NULL);
285 
286 	/* Add duration to current time */
287 	s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
288 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
289 	    &s->d1->next_timeout);
290 }
291 
292 struct timeval*
293 dtls1_get_timeout(SSL *s, struct timeval* timeleft)
294 {
295 	struct timeval timenow;
296 
297 	/* If no timeout is set, just return NULL */
298 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
299 		return NULL;
300 	}
301 
302 	/* Get current time */
303 	gettimeofday(&timenow, NULL);
304 
305 	/* If timer already expired, set remaining time to 0 */
306 	if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
307 	    (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
308 	     s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
309 		memset(timeleft, 0, sizeof(struct timeval));
310 		return timeleft;
311 	}
312 
313 	/* Calculate time left until timer expires */
314 	memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
315 	timeleft->tv_sec -= timenow.tv_sec;
316 	timeleft->tv_usec -= timenow.tv_usec;
317 	if (timeleft->tv_usec < 0) {
318 		timeleft->tv_sec--;
319 		timeleft->tv_usec += 1000000;
320 	}
321 
322 	/* If remaining time is less than 15 ms, set it to 0
323 	 * to prevent issues because of small devergences with
324 	 * socket timeouts.
325 	 */
326 	if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
327 		memset(timeleft, 0, sizeof(struct timeval));
328 	}
329 
330 
331 	return timeleft;
332 }
333 
334 int
335 dtls1_is_timer_expired(SSL *s)
336 {
337 	struct timeval timeleft;
338 
339 	/* Get time left until timeout, return false if no timer running */
340 	if (dtls1_get_timeout(s, &timeleft) == NULL) {
341 		return 0;
342 	}
343 
344 	/* Return false if timer is not expired yet */
345 	if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
346 		return 0;
347 	}
348 
349 	/* Timer expired, so return true */
350 	return 1;
351 }
352 
353 void
354 dtls1_double_timeout(SSL *s)
355 {
356 	s->d1->timeout_duration *= 2;
357 	if (s->d1->timeout_duration > 60)
358 		s->d1->timeout_duration = 60;
359 	dtls1_start_timer(s);
360 }
361 
362 void
363 dtls1_stop_timer(SSL *s)
364 {
365 	/* Reset everything */
366 	memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
367 	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
368 	s->d1->timeout_duration = 1;
369 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
370 	    &(s->d1->next_timeout));
371 	/* Clear retransmission buffer */
372 	dtls1_clear_record_buffer(s);
373 }
374 
375 int
376 dtls1_check_timeout_num(SSL *s)
377 {
378 	s->d1->timeout.num_alerts++;
379 
380 	/* Reduce MTU after 2 unsuccessful retransmissions */
381 	if (s->d1->timeout.num_alerts > 2) {
382 		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
383 		    BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
384 
385 	}
386 
387 	if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
388 		/* fail the connection, enough alerts have been sent */
389 		SSLerror(s, SSL_R_READ_TIMEOUT_EXPIRED);
390 		return -1;
391 	}
392 
393 	return 0;
394 }
395 
396 int
397 dtls1_handle_timeout(SSL *s)
398 {
399 	/* if no timer is expired, don't do anything */
400 	if (!dtls1_is_timer_expired(s)) {
401 		return 0;
402 	}
403 
404 	dtls1_double_timeout(s);
405 
406 	if (dtls1_check_timeout_num(s) < 0)
407 		return -1;
408 
409 	s->d1->timeout.read_timeouts++;
410 	if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
411 		s->d1->timeout.read_timeouts = 1;
412 	}
413 
414 	dtls1_start_timer(s);
415 	return dtls1_retransmit_buffered_messages(s);
416 }
417 
418 int
419 dtls1_listen(SSL *s, struct sockaddr *client)
420 {
421 	int ret;
422 
423 	/* Ensure there is no state left over from a previous invocation */
424 	SSL_clear(s);
425 
426 	SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
427 	s->d1->listen = 1;
428 
429 	ret = SSL_accept(s);
430 	if (ret <= 0)
431 		return ret;
432 
433 	(void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
434 	return 1;
435 }
436