d1_lib.c revision 296465 
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#if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS)
66# include <sys/timeb.h>
67#endif
68
69static void get_current_time(struct timeval *t);
70const char dtls1_version_str[] = "DTLSv1" OPENSSL_VERSION_PTEXT;
71int dtls1_listen(SSL *s, struct sockaddr *client);
72
73SSL3_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
87long dtls1_default_timeout(void)
88{
89    /*
90     * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
91     * http, the cache would over fill
92     */
93    return (60 * 60 * 2);
94}
95
96IMPLEMENT_dtls1_meth_func(dtlsv1_base_method,
97                          ssl_undefined_function,
98                          ssl_undefined_function, ssl_bad_method)
99
100int dtls1_new(SSL *s)
101{
102    DTLS1_STATE *d1;
103
104    if (!ssl3_new(s))
105        return (0);
106    if ((d1 = OPENSSL_malloc(sizeof *d1)) == NULL)
107        return (0);
108    memset(d1, 0, sizeof *d1);
109
110    /* d1->handshake_epoch=0; */
111#if defined(OPENSSL_SYS_VMS) || defined(VMS_TEST)
112    d1->bitmap.length = 64;
113#else
114    d1->bitmap.length = sizeof(d1->bitmap.map) * 8;
115#endif
116    pq_64bit_init(&(d1->bitmap.map));
117    pq_64bit_init(&(d1->bitmap.max_seq_num));
118
119    d1->next_bitmap.length = d1->bitmap.length;
120    pq_64bit_init(&(d1->next_bitmap.map));
121    pq_64bit_init(&(d1->next_bitmap.max_seq_num));
122
123    d1->unprocessed_rcds.q = pqueue_new();
124    d1->processed_rcds.q = pqueue_new();
125    d1->buffered_messages = pqueue_new();
126    d1->sent_messages = pqueue_new();
127    d1->buffered_app_data.q = pqueue_new();
128
129    if (s->server) {
130        d1->cookie_len = sizeof(s->d1->cookie);
131    }
132
133    if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q
134        || !d1->buffered_messages || !d1->sent_messages
135        || !d1->buffered_app_data.q) {
136        if (d1->unprocessed_rcds.q)
137            pqueue_free(d1->unprocessed_rcds.q);
138        if (d1->processed_rcds.q)
139            pqueue_free(d1->processed_rcds.q);
140        if (d1->buffered_messages)
141            pqueue_free(d1->buffered_messages);
142        if (d1->sent_messages)
143            pqueue_free(d1->sent_messages);
144        if (d1->buffered_app_data.q)
145            pqueue_free(d1->buffered_app_data.q);
146        OPENSSL_free(d1);
147        return (0);
148    }
149
150    s->d1 = d1;
151    s->method->ssl_clear(s);
152    return (1);
153}
154
155static void dtls1_clear_queues(SSL *s)
156{
157    pitem *item = NULL;
158    hm_fragment *frag = NULL;
159    DTLS1_RECORD_DATA *rdata;
160
161    while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) {
162        rdata = (DTLS1_RECORD_DATA *)item->data;
163        if (rdata->rbuf.buf) {
164            OPENSSL_free(rdata->rbuf.buf);
165        }
166        OPENSSL_free(item->data);
167        pitem_free(item);
168    }
169
170    while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
171        rdata = (DTLS1_RECORD_DATA *)item->data;
172        if (rdata->rbuf.buf) {
173            OPENSSL_free(rdata->rbuf.buf);
174        }
175        OPENSSL_free(item->data);
176        pitem_free(item);
177    }
178
179    while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
180        frag = (hm_fragment *)item->data;
181        OPENSSL_free(frag->fragment);
182        OPENSSL_free(frag);
183        pitem_free(item);
184    }
185
186    while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
187        frag = (hm_fragment *)item->data;
188        OPENSSL_free(frag->fragment);
189        OPENSSL_free(frag);
190        pitem_free(item);
191    }
192
193    while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) {
194        rdata = (DTLS1_RECORD_DATA *)item->data;
195        if (rdata->rbuf.buf) {
196            OPENSSL_free(rdata->rbuf.buf);
197        }
198        OPENSSL_free(item->data);
199        pitem_free(item);
200    }
201}
202
203void dtls1_free(SSL *s)
204{
205    ssl3_free(s);
206
207    dtls1_clear_queues(s);
208
209    pqueue_free(s->d1->unprocessed_rcds.q);
210    pqueue_free(s->d1->processed_rcds.q);
211    pqueue_free(s->d1->buffered_messages);
212    pqueue_free(s->d1->sent_messages);
213    pqueue_free(s->d1->buffered_app_data.q);
214
215    pq_64bit_free(&(s->d1->bitmap.map));
216    pq_64bit_free(&(s->d1->bitmap.max_seq_num));
217
218    pq_64bit_free(&(s->d1->next_bitmap.map));
219    pq_64bit_free(&(s->d1->next_bitmap.max_seq_num));
220
221    OPENSSL_free(s->d1);
222    s->d1 = NULL;
223}
224
225void dtls1_clear(SSL *s)
226{
227    pqueue unprocessed_rcds;
228    pqueue processed_rcds;
229    pqueue buffered_messages;
230    pqueue sent_messages;
231    pqueue buffered_app_data;
232    unsigned int mtu;
233
234    if (s->d1) {
235        unprocessed_rcds = s->d1->unprocessed_rcds.q;
236        processed_rcds = s->d1->processed_rcds.q;
237        buffered_messages = s->d1->buffered_messages;
238        sent_messages = s->d1->sent_messages;
239        buffered_app_data = s->d1->buffered_app_data.q;
240        mtu = s->d1->mtu;
241
242        dtls1_clear_queues(s);
243
244        pq_64bit_free(&(s->d1->bitmap.map));
245        pq_64bit_free(&(s->d1->bitmap.max_seq_num));
246
247        pq_64bit_free(&(s->d1->next_bitmap.map));
248        pq_64bit_free(&(s->d1->next_bitmap.max_seq_num));
249
250        memset(s->d1, 0, sizeof(*(s->d1)));
251
252        if (s->server) {
253            s->d1->cookie_len = sizeof(s->d1->cookie);
254        }
255
256        if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
257            s->d1->mtu = mtu;
258        }
259
260        s->d1->unprocessed_rcds.q = unprocessed_rcds;
261        s->d1->processed_rcds.q = processed_rcds;
262        s->d1->buffered_messages = buffered_messages;
263        s->d1->sent_messages = sent_messages;
264        s->d1->buffered_app_data.q = buffered_app_data;
265
266#if defined(OPENSSL_SYS_VMS) || defined(VMS_TEST)
267        s->d1->bitmap.length = 64;
268#else
269        s->d1->bitmap.length = sizeof(s->d1->bitmap.map) * 8;
270#endif
271        pq_64bit_init(&(s->d1->bitmap.map));
272        pq_64bit_init(&(s->d1->bitmap.max_seq_num));
273
274        s->d1->next_bitmap.length = s->d1->bitmap.length;
275        pq_64bit_init(&(s->d1->next_bitmap.map));
276        pq_64bit_init(&(s->d1->next_bitmap.max_seq_num));
277    }
278
279    ssl3_clear(s);
280    if (s->options & SSL_OP_CISCO_ANYCONNECT)
281        s->version = DTLS1_BAD_VER;
282    else
283        s->version = DTLS1_VERSION;
284}
285
286long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
287{
288    int ret = 0;
289
290    switch (cmd) {
291    case DTLS_CTRL_GET_TIMEOUT:
292        if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
293            ret = 1;
294        }
295        break;
296    case DTLS_CTRL_HANDLE_TIMEOUT:
297        ret = dtls1_handle_timeout(s);
298        break;
299    case DTLS_CTRL_LISTEN:
300        ret = dtls1_listen(s, parg);
301        break;
302    case SSL_CTRL_CHECK_PROTO_VERSION:
303        /*
304         * For library-internal use; checks that the current protocol is the
305         * highest enabled version (according to s->ctx->method, as version
306         * negotiation may have changed s->method).
307         */
308#if DTLS_MAX_VERSION != DTLS1_VERSION
309# error Code needs update for DTLS_method() support beyond DTLS1_VERSION.
310#endif
311        /*
312         * Just one protocol version is supported so far; fail closed if the
313         * version is not as expected.
314         */
315        return s->version == DTLS_MAX_VERSION;
316
317    default:
318        ret = ssl3_ctrl(s, cmd, larg, parg);
319        break;
320    }
321    return (ret);
322}
323
324/*
325 * As it's impossible to use stream ciphers in "datagram" mode, this
326 * simple filter is designed to disengage them in DTLS. Unfortunately
327 * there is no universal way to identify stream SSL_CIPHER, so we have
328 * to explicitly list their SSL_* codes. Currently RC4 is the only one
329 * available, but if new ones emerge, they will have to be added...
330 */
331SSL_CIPHER *dtls1_get_cipher(unsigned int u)
332{
333    SSL_CIPHER *ciph = ssl3_get_cipher(u);
334
335    if (ciph != NULL) {
336        if ((ciph->algorithms & SSL_ENC_MASK) == SSL_RC4)
337            return NULL;
338    }
339
340    return ciph;
341}
342
343void dtls1_start_timer(SSL *s)
344{
345    /* If timer is not set, initialize duration with 1 second */
346    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
347        s->d1->timeout_duration = 1;
348    }
349
350    /* Set timeout to current time */
351    get_current_time(&(s->d1->next_timeout));
352
353    /* Add duration to current time */
354    s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
355    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
356             &(s->d1->next_timeout));
357}
358
359struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
360{
361    struct timeval timenow;
362
363    /* If no timeout is set, just return NULL */
364    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
365        return NULL;
366    }
367
368    /* Get current time */
369    get_current_time(&timenow);
370
371    /* If timer already expired, set remaining time to 0 */
372    if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
373        (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
374         s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
375        memset(timeleft, 0, sizeof(struct timeval));
376        return timeleft;
377    }
378
379    /* Calculate time left until timer expires */
380    memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
381    timeleft->tv_sec -= timenow.tv_sec;
382    timeleft->tv_usec -= timenow.tv_usec;
383    if (timeleft->tv_usec < 0) {
384        timeleft->tv_sec--;
385        timeleft->tv_usec += 1000000;
386    }
387
388    /*
389     * If remaining time is less than 15 ms, set it to 0 to prevent issues
390     * because of small devergences with socket timeouts.
391     */
392    if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
393        memset(timeleft, 0, sizeof(struct timeval));
394    }
395
396    return timeleft;
397}
398
399int dtls1_is_timer_expired(SSL *s)
400{
401    struct timeval timeleft;
402
403    /* Get time left until timeout, return false if no timer running */
404    if (dtls1_get_timeout(s, &timeleft) == NULL) {
405        return 0;
406    }
407
408    /* Return false if timer is not expired yet */
409    if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
410        return 0;
411    }
412
413    /* Timer expired, so return true */
414    return 1;
415}
416
417void dtls1_double_timeout(SSL *s)
418{
419    s->d1->timeout_duration *= 2;
420    if (s->d1->timeout_duration > 60)
421        s->d1->timeout_duration = 60;
422    dtls1_start_timer(s);
423}
424
425void dtls1_stop_timer(SSL *s)
426{
427    /* Reset everything */
428    memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
429    memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
430    s->d1->timeout_duration = 1;
431    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
432             &(s->d1->next_timeout));
433    /* Clear retransmission buffer */
434    dtls1_clear_record_buffer(s);
435}
436
437int dtls1_check_timeout_num(SSL *s)
438{
439    s->d1->timeout.num_alerts++;
440
441    /* Reduce MTU after 2 unsuccessful retransmissions */
442    if (s->d1->timeout.num_alerts > 2) {
443        s->d1->mtu =
444            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
445                     NULL);
446    }
447
448    if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
449        /* fail the connection, enough alerts have been sent */
450        SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
451        return -1;
452    }
453
454    return 0;
455}
456
457int dtls1_handle_timeout(SSL *s)
458{
459    /* if no timer is expired, don't do anything */
460    if (!dtls1_is_timer_expired(s)) {
461        return 0;
462    }
463
464    dtls1_double_timeout(s);
465
466    if (dtls1_check_timeout_num(s) < 0)
467        return -1;
468
469    s->d1->timeout.read_timeouts++;
470    if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
471        s->d1->timeout.read_timeouts = 1;
472    }
473
474    dtls1_start_timer(s);
475    return dtls1_retransmit_buffered_messages(s);
476}
477
478static void get_current_time(struct timeval *t)
479{
480#ifdef OPENSSL_SYS_WIN32
481    struct _timeb tb;
482    _ftime(&tb);
483    t->tv_sec = (long)tb.time;
484    t->tv_usec = (long)tb.millitm * 1000;
485#elif defined(OPENSSL_SYS_VMS)
486    struct timeb tb;
487    ftime(&tb);
488    t->tv_sec = (long)tb.time;
489    t->tv_usec = (long)tb.millitm * 1000;
490#else
491    gettimeofday(t, NULL);
492#endif
493}
494
495int dtls1_listen(SSL *s, struct sockaddr *client)
496{
497    int ret;
498
499    /* Ensure there is no state left over from a previous invocation */
500    SSL_clear(s);
501
502    SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
503    s->d1->listen = 1;
504
505    ret = SSL_accept(s);
506    if (ret <= 0)
507        return ret;
508
509    (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
510    return 1;
511}
512