d1_lib.c revision 296341 
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    tls1_export_keying_material,
86};
87
88long dtls1_default_timeout(void)
89{
90    /*
91     * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
92     * http, the cache would over fill
93     */
94    return (60 * 60 * 2);
95}
96
97int dtls1_new(SSL *s)
98{
99    DTLS1_STATE *d1;
100
101    if (!ssl3_new(s))
102        return (0);
103    if ((d1 = OPENSSL_malloc(sizeof *d1)) == NULL)
104        return (0);
105    memset(d1, 0, sizeof *d1);
106
107    /* d1->handshake_epoch=0; */
108
109    d1->unprocessed_rcds.q = pqueue_new();
110    d1->processed_rcds.q = pqueue_new();
111    d1->buffered_messages = pqueue_new();
112    d1->sent_messages = pqueue_new();
113    d1->buffered_app_data.q = pqueue_new();
114
115    if (s->server) {
116        d1->cookie_len = sizeof(s->d1->cookie);
117    }
118
119    d1->link_mtu = 0;
120    d1->mtu = 0;
121
122    if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q
123        || !d1->buffered_messages || !d1->sent_messages
124        || !d1->buffered_app_data.q) {
125        if (d1->unprocessed_rcds.q)
126            pqueue_free(d1->unprocessed_rcds.q);
127        if (d1->processed_rcds.q)
128            pqueue_free(d1->processed_rcds.q);
129        if (d1->buffered_messages)
130            pqueue_free(d1->buffered_messages);
131        if (d1->sent_messages)
132            pqueue_free(d1->sent_messages);
133        if (d1->buffered_app_data.q)
134            pqueue_free(d1->buffered_app_data.q);
135        OPENSSL_free(d1);
136        return (0);
137    }
138
139    s->d1 = d1;
140    s->method->ssl_clear(s);
141    return (1);
142}
143
144static void 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        if (rdata->rbuf.buf) {
153            OPENSSL_free(rdata->rbuf.buf);
154        }
155        OPENSSL_free(item->data);
156        pitem_free(item);
157    }
158
159    while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
160        rdata = (DTLS1_RECORD_DATA *)item->data;
161        if (rdata->rbuf.buf) {
162            OPENSSL_free(rdata->rbuf.buf);
163        }
164        OPENSSL_free(item->data);
165        pitem_free(item);
166    }
167
168    while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
169        frag = (hm_fragment *)item->data;
170        dtls1_hm_fragment_free(frag);
171        pitem_free(item);
172    }
173
174    while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
175        frag = (hm_fragment *)item->data;
176        dtls1_hm_fragment_free(frag);
177        pitem_free(item);
178    }
179
180    while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) {
181        rdata = (DTLS1_RECORD_DATA *)item->data;
182        if (rdata->rbuf.buf) {
183            OPENSSL_free(rdata->rbuf.buf);
184        }
185        OPENSSL_free(item->data);
186        pitem_free(item);
187    }
188}
189
190void dtls1_free(SSL *s)
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    OPENSSL_free(s->d1);
203    s->d1 = NULL;
204}
205
206void dtls1_clear(SSL *s)
207{
208    pqueue unprocessed_rcds;
209    pqueue processed_rcds;
210    pqueue buffered_messages;
211    pqueue sent_messages;
212    pqueue buffered_app_data;
213    unsigned int mtu;
214    unsigned int link_mtu;
215
216    if (s->d1) {
217        unprocessed_rcds = s->d1->unprocessed_rcds.q;
218        processed_rcds = s->d1->processed_rcds.q;
219        buffered_messages = s->d1->buffered_messages;
220        sent_messages = s->d1->sent_messages;
221        buffered_app_data = s->d1->buffered_app_data.q;
222        mtu = s->d1->mtu;
223        link_mtu = s->d1->link_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            s->d1->link_mtu = link_mtu;
236        }
237
238        s->d1->unprocessed_rcds.q = unprocessed_rcds;
239        s->d1->processed_rcds.q = processed_rcds;
240        s->d1->buffered_messages = buffered_messages;
241        s->d1->sent_messages = sent_messages;
242        s->d1->buffered_app_data.q = buffered_app_data;
243    }
244
245    ssl3_clear(s);
246    if (s->options & SSL_OP_CISCO_ANYCONNECT)
247        s->version = DTLS1_BAD_VER;
248    else
249        s->version = DTLS1_VERSION;
250}
251
252long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
253{
254    int ret = 0;
255
256    switch (cmd) {
257    case DTLS_CTRL_GET_TIMEOUT:
258        if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
259            ret = 1;
260        }
261        break;
262    case DTLS_CTRL_HANDLE_TIMEOUT:
263        ret = dtls1_handle_timeout(s);
264        break;
265    case DTLS_CTRL_LISTEN:
266        ret = dtls1_listen(s, parg);
267        break;
268    case SSL_CTRL_CHECK_PROTO_VERSION:
269        /*
270         * For library-internal use; checks that the current protocol is the
271         * highest enabled version (according to s->ctx->method, as version
272         * negotiation may have changed s->method).
273         */
274#if DTLS_MAX_VERSION != DTLS1_VERSION
275# error Code needs update for DTLS_method() support beyond DTLS1_VERSION.
276#endif
277        /*
278         * Just one protocol version is supported so far; fail closed if the
279         * version is not as expected.
280         */
281        return s->version == DTLS_MAX_VERSION;
282    case DTLS_CTRL_SET_LINK_MTU:
283        if (larg < (long)dtls1_link_min_mtu())
284            return 0;
285        s->d1->link_mtu = larg;
286        return 1;
287    case DTLS_CTRL_GET_LINK_MIN_MTU:
288        return (long)dtls1_link_min_mtu();
289    case SSL_CTRL_SET_MTU:
290        /*
291         *  We may not have a BIO set yet so can't call dtls1_min_mtu()
292         *  We'll have to make do with dtls1_link_min_mtu() and max overhead
293         */
294        if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
295            return 0;
296        s->d1->mtu = larg;
297        return larg;
298    default:
299        ret = ssl3_ctrl(s, cmd, larg, parg);
300        break;
301    }
302    return (ret);
303}
304
305/*
306 * As it's impossible to use stream ciphers in "datagram" mode, this
307 * simple filter is designed to disengage them in DTLS. Unfortunately
308 * there is no universal way to identify stream SSL_CIPHER, so we have
309 * to explicitly list their SSL_* codes. Currently RC4 is the only one
310 * available, but if new ones emerge, they will have to be added...
311 */
312const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
313{
314    const SSL_CIPHER *ciph = ssl3_get_cipher(u);
315
316    if (ciph != NULL) {
317        if (ciph->algorithm_enc == SSL_RC4)
318            return NULL;
319    }
320
321    return ciph;
322}
323
324void dtls1_start_timer(SSL *s)
325{
326#ifndef OPENSSL_NO_SCTP
327    /* Disable timer for SCTP */
328    if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
329        memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
330        return;
331    }
332#endif
333
334    /* If timer is not set, initialize duration with 1 second */
335    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
336        s->d1->timeout_duration = 1;
337    }
338
339    /* Set timeout to current time */
340    get_current_time(&(s->d1->next_timeout));
341
342    /* Add duration to current time */
343    s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
344    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
345             &(s->d1->next_timeout));
346}
347
348struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
349{
350    struct timeval timenow;
351
352    /* If no timeout is set, just return NULL */
353    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
354        return NULL;
355    }
356
357    /* Get current time */
358    get_current_time(&timenow);
359
360    /* If timer already expired, set remaining time to 0 */
361    if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
362        (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
363         s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
364        memset(timeleft, 0, sizeof(struct timeval));
365        return timeleft;
366    }
367
368    /* Calculate time left until timer expires */
369    memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
370    timeleft->tv_sec -= timenow.tv_sec;
371    timeleft->tv_usec -= timenow.tv_usec;
372    if (timeleft->tv_usec < 0) {
373        timeleft->tv_sec--;
374        timeleft->tv_usec += 1000000;
375    }
376
377    /*
378     * If remaining time is less than 15 ms, set it to 0 to prevent issues
379     * because of small devergences with socket timeouts.
380     */
381    if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
382        memset(timeleft, 0, sizeof(struct timeval));
383    }
384
385    return timeleft;
386}
387
388int dtls1_is_timer_expired(SSL *s)
389{
390    struct timeval timeleft;
391
392    /* Get time left until timeout, return false if no timer running */
393    if (dtls1_get_timeout(s, &timeleft) == NULL) {
394        return 0;
395    }
396
397    /* Return false if timer is not expired yet */
398    if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
399        return 0;
400    }
401
402    /* Timer expired, so return true */
403    return 1;
404}
405
406void dtls1_double_timeout(SSL *s)
407{
408    s->d1->timeout_duration *= 2;
409    if (s->d1->timeout_duration > 60)
410        s->d1->timeout_duration = 60;
411    dtls1_start_timer(s);
412}
413
414void dtls1_stop_timer(SSL *s)
415{
416    /* Reset everything */
417    memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
418    memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
419    s->d1->timeout_duration = 1;
420    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
421             &(s->d1->next_timeout));
422    /* Clear retransmission buffer */
423    dtls1_clear_record_buffer(s);
424}
425
426int dtls1_check_timeout_num(SSL *s)
427{
428    unsigned int mtu;
429
430    s->d1->timeout.num_alerts++;
431
432    /* Reduce MTU after 2 unsuccessful retransmissions */
433    if (s->d1->timeout.num_alerts > 2
434        && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
435        mtu =
436            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
437                     NULL);
438        if (mtu < s->d1->mtu)
439            s->d1->mtu = mtu;
440    }
441
442    if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
443        /* fail the connection, enough alerts have been sent */
444        SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
445        return -1;
446    }
447
448    return 0;
449}
450
451int dtls1_handle_timeout(SSL *s)
452{
453    /* if no timer is expired, don't do anything */
454    if (!dtls1_is_timer_expired(s)) {
455        return 0;
456    }
457
458    dtls1_double_timeout(s);
459
460    if (dtls1_check_timeout_num(s) < 0)
461        return -1;
462
463    s->d1->timeout.read_timeouts++;
464    if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
465        s->d1->timeout.read_timeouts = 1;
466    }
467#ifndef OPENSSL_NO_HEARTBEATS
468    if (s->tlsext_hb_pending) {
469        s->tlsext_hb_pending = 0;
470        return dtls1_heartbeat(s);
471    }
472#endif
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