1 /* ssl/d1_lib.c */
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 <stdio.h>
61 #define USE_SOCKETS
62 #include <openssl/objects.h>
63 #include "ssl_locl.h"
64 
65 #ifdef OPENSSL_SYS_WIN32
66 #include <sys/timeb.h>
67 #endif
68 
69 static void get_current_time(struct timeval *t);
70 const char dtls1_version_str[]="DTLSv1" OPENSSL_VERSION_PTEXT;
71 int dtls1_listen(SSL *s, struct sockaddr *client);
72 
73 SSL3_ENC_METHOD DTLSv1_enc_data={
74     dtls1_enc,
75 	tls1_mac,
76 	tls1_setup_key_block,
77 	tls1_generate_master_secret,
78 	tls1_change_cipher_state,
79 	tls1_final_finish_mac,
80 	TLS1_FINISH_MAC_LENGTH,
81 	tls1_cert_verify_mac,
82 	TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
83 	TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
84 	tls1_alert_code,
85 	};
86 
87 long dtls1_default_timeout(void)
88 	{
89 	/* 2 hours, the 24 hours mentioned in the DTLSv1 spec
90 	 * is way too long for http, the cache would over fill */
91 	return(60*60*2);
92 	}
93 
94 int dtls1_new(SSL *s)
95 	{
96 	DTLS1_STATE *d1;
97 
98 	if (!ssl3_new(s)) return(0);
99 	if ((d1=OPENSSL_malloc(sizeof *d1)) == NULL) return (0);
100 	memset(d1,0, sizeof *d1);
101 
102 	/* d1->handshake_epoch=0; */
103 
104 	d1->unprocessed_rcds.q=pqueue_new();
105 	d1->processed_rcds.q=pqueue_new();
106 	d1->buffered_messages = pqueue_new();
107 	d1->sent_messages=pqueue_new();
108 	d1->buffered_app_data.q=pqueue_new();
109 
110 	if ( s->server)
111 		{
112 		d1->cookie_len = sizeof(s->d1->cookie);
113 		}
114 
115 	if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q
116         || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q)
117 		{
118         if ( d1->unprocessed_rcds.q) pqueue_free(d1->unprocessed_rcds.q);
119         if ( d1->processed_rcds.q) pqueue_free(d1->processed_rcds.q);
120         if ( d1->buffered_messages) pqueue_free(d1->buffered_messages);
121 		if ( d1->sent_messages) pqueue_free(d1->sent_messages);
122 		if ( d1->buffered_app_data.q) pqueue_free(d1->buffered_app_data.q);
123 		OPENSSL_free(d1);
124 		return (0);
125 		}
126 
127 	s->d1=d1;
128 	s->method->ssl_clear(s);
129 	return(1);
130 	}
131 
132 void dtls1_free(SSL *s)
133 	{
134     pitem *item = NULL;
135     hm_fragment *frag = NULL;
136 
137 	ssl3_free(s);
138 
139     while( (item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL)
140         {
141         OPENSSL_free(item->data);
142         pitem_free(item);
143         }
144     pqueue_free(s->d1->unprocessed_rcds.q);
145 
146     while( (item = pqueue_pop(s->d1->processed_rcds.q)) != NULL)
147         {
148         OPENSSL_free(item->data);
149         pitem_free(item);
150         }
151     pqueue_free(s->d1->processed_rcds.q);
152 
153     while( (item = pqueue_pop(s->d1->buffered_messages)) != NULL)
154         {
155         frag = (hm_fragment *)item->data;
156         OPENSSL_free(frag->fragment);
157         OPENSSL_free(frag);
158         pitem_free(item);
159         }
160     pqueue_free(s->d1->buffered_messages);
161 
162     while ( (item = pqueue_pop(s->d1->sent_messages)) != NULL)
163         {
164         frag = (hm_fragment *)item->data;
165         OPENSSL_free(frag->fragment);
166         OPENSSL_free(frag);
167         pitem_free(item);
168         }
169 	pqueue_free(s->d1->sent_messages);
170 
171 	while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL)
172 		{
173 		frag = (hm_fragment *)item->data;
174 		OPENSSL_free(frag->fragment);
175 		OPENSSL_free(frag);
176 		pitem_free(item);
177 		}
178 	pqueue_free(s->d1->buffered_app_data.q);
179 
180 	OPENSSL_free(s->d1);
181 	}
182 
183 void dtls1_clear(SSL *s)
184 	{
185 	ssl3_clear(s);
186 	if (s->options & SSL_OP_CISCO_ANYCONNECT)
187 		s->version=DTLS1_BAD_VER;
188 	else
189 		s->version=DTLS1_VERSION;
190 	}
191 
192 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
193 	{
194 	int ret=0;
195 
196 	switch (cmd)
197 		{
198 	case DTLS_CTRL_GET_TIMEOUT:
199 		if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL)
200 			{
201 			ret = 1;
202 			}
203 		break;
204 	case DTLS_CTRL_HANDLE_TIMEOUT:
205 		ret = dtls1_handle_timeout(s);
206 		break;
207 	case DTLS_CTRL_LISTEN:
208 		ret = dtls1_listen(s, parg);
209 		break;
210 
211 	default:
212 		ret = ssl3_ctrl(s, cmd, larg, parg);
213 		break;
214 		}
215 	return(ret);
216 	}
217 
218 /*
219  * As it's impossible to use stream ciphers in "datagram" mode, this
220  * simple filter is designed to disengage them in DTLS. Unfortunately
221  * there is no universal way to identify stream SSL_CIPHER, so we have
222  * to explicitly list their SSL_* codes. Currently RC4 is the only one
223  * available, but if new ones emerge, they will have to be added...
224  */
225 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
226 	{
227 	const SSL_CIPHER *ciph = ssl3_get_cipher(u);
228 
229 	if (ciph != NULL)
230 		{
231 		if (ciph->algorithm_enc == SSL_RC4)
232 			return NULL;
233 		}
234 
235 	return ciph;
236 	}
237 
238 void dtls1_start_timer(SSL *s)
239 	{
240 	/* If timer is not set, initialize duration with 1 second */
241 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
242 		{
243 		s->d1->timeout_duration = 1;
244 		}
245 
246 	/* Set timeout to current time */
247 	get_current_time(&(s->d1->next_timeout));
248 
249 	/* Add duration to current time */
250 	s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
251 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
252 	}
253 
254 struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft)
255 	{
256 	struct timeval timenow;
257 
258 	/* If no timeout is set, just return NULL */
259 	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
260 		{
261 		return NULL;
262 		}
263 
264 	/* Get current time */
265 	get_current_time(&timenow);
266 
267 	/* If timer already expired, set remaining time to 0 */
268 	if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
269 		(s->d1->next_timeout.tv_sec == timenow.tv_sec &&
270 		 s->d1->next_timeout.tv_usec <= timenow.tv_usec))
271 		{
272 		memset(timeleft, 0, sizeof(struct timeval));
273 		return timeleft;
274 		}
275 
276 	/* Calculate time left until timer expires */
277 	memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
278 	timeleft->tv_sec -= timenow.tv_sec;
279 	timeleft->tv_usec -= timenow.tv_usec;
280 	if (timeleft->tv_usec < 0)
281 		{
282 		timeleft->tv_sec--;
283 		timeleft->tv_usec += 1000000;
284 		}
285 
286 	return timeleft;
287 	}
288 
289 int dtls1_is_timer_expired(SSL *s)
290 	{
291 	struct timeval timeleft;
292 
293 	/* Get time left until timeout, return false if no timer running */
294 	if (dtls1_get_timeout(s, &timeleft) == NULL)
295 		{
296 		return 0;
297 		}
298 
299 	/* Return false if timer is not expired yet */
300 	if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0)
301 		{
302 		return 0;
303 		}
304 
305 	/* Timer expired, so return true */
306 	return 1;
307 	}
308 
309 void dtls1_double_timeout(SSL *s)
310 	{
311 	s->d1->timeout_duration *= 2;
312 	if (s->d1->timeout_duration > 60)
313 		s->d1->timeout_duration = 60;
314 	dtls1_start_timer(s);
315 	}
316 
317 void dtls1_stop_timer(SSL *s)
318 	{
319 	/* Reset everything */
320 	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
321 	s->d1->timeout_duration = 1;
322 	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
323 	}
324 
325 int dtls1_handle_timeout(SSL *s)
326 	{
327 	DTLS1_STATE *state;
328 
329 	/* if no timer is expired, don't do anything */
330 	if (!dtls1_is_timer_expired(s))
331 		{
332 		return 0;
333 		}
334 
335 	dtls1_double_timeout(s);
336 	state = s->d1;
337 	state->timeout.num_alerts++;
338 	if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
339 		{
340 		/* fail the connection, enough alerts have been sent */
341 		SSLerr(SSL_F_DTLS1_HANDLE_TIMEOUT,SSL_R_READ_TIMEOUT_EXPIRED);
342 		return 0;
343 		}
344 
345 	state->timeout.read_timeouts++;
346 	if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
347 		{
348 		state->timeout.read_timeouts = 1;
349 		}
350 
351 	dtls1_start_timer(s);
352 	return dtls1_retransmit_buffered_messages(s);
353 	}
354 
355 static void get_current_time(struct timeval *t)
356 {
357 #ifdef OPENSSL_SYS_WIN32
358 	struct _timeb tb;
359 	_ftime(&tb);
360 	t->tv_sec = (long)tb.time;
361 	t->tv_usec = (long)tb.millitm * 1000;
362 #elif defined(OPENSSL_SYS_VMS)
363 	struct timeb tb;
364 	ftime(&tb);
365 	t->tv_sec = (long)tb.time;
366 	t->tv_usec = (long)tb.millitm * 1000;
367 #else
368 	gettimeofday(t, NULL);
369 #endif
370 }
371 
372 int dtls1_listen(SSL *s, struct sockaddr *client)
373 	{
374 	int ret;
375 
376 	SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
377 	s->d1->listen = 1;
378 
379 	ret = SSL_accept(s);
380 	if (ret <= 0) return ret;
381 
382 	(void) BIO_dgram_get_peer(SSL_get_rbio(s), client);
383 	return 1;
384 	}
385