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_VMS)
66# include <sys/timeb.h>
67#endif
68
69static void get_current_time(struct timeval *t);
70static void dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
71static int dtls1_handshake_write(SSL *s);
72const char dtls1_version_str[] = "DTLSv1" OPENSSL_VERSION_PTEXT;
73int dtls1_listen(SSL *s, struct sockaddr *client);
74
75SSL3_ENC_METHOD DTLSv1_enc_data = {
76    tls1_enc,
77    tls1_mac,
78    tls1_setup_key_block,
79    tls1_generate_master_secret,
80    tls1_change_cipher_state,
81    tls1_final_finish_mac,
82    TLS1_FINISH_MAC_LENGTH,
83    tls1_cert_verify_mac,
84    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
85    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
86    tls1_alert_code,
87    tls1_export_keying_material,
88    SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
89    DTLS1_HM_HEADER_LENGTH,
90    dtls1_set_handshake_header,
91    dtls1_handshake_write
92};
93
94SSL3_ENC_METHOD DTLSv1_2_enc_data = {
95    tls1_enc,
96    tls1_mac,
97    tls1_setup_key_block,
98    tls1_generate_master_secret,
99    tls1_change_cipher_state,
100    tls1_final_finish_mac,
101    TLS1_FINISH_MAC_LENGTH,
102    tls1_cert_verify_mac,
103    TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
104    TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
105    tls1_alert_code,
106    tls1_export_keying_material,
107    SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
108        | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
109    DTLS1_HM_HEADER_LENGTH,
110    dtls1_set_handshake_header,
111    dtls1_handshake_write
112};
113
114long dtls1_default_timeout(void)
115{
116    /*
117     * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
118     * http, the cache would over fill
119     */
120    return (60 * 60 * 2);
121}
122
123int dtls1_new(SSL *s)
124{
125    DTLS1_STATE *d1;
126
127    if (!ssl3_new(s))
128        return (0);
129    if ((d1 = OPENSSL_malloc(sizeof *d1)) == NULL)
130        return (0);
131    memset(d1, 0, sizeof *d1);
132
133    /* d1->handshake_epoch=0; */
134
135    d1->unprocessed_rcds.q = pqueue_new();
136    d1->processed_rcds.q = pqueue_new();
137    d1->buffered_messages = pqueue_new();
138    d1->sent_messages = pqueue_new();
139    d1->buffered_app_data.q = pqueue_new();
140
141    if (s->server) {
142        d1->cookie_len = sizeof(s->d1->cookie);
143    }
144
145    d1->link_mtu = 0;
146    d1->mtu = 0;
147
148    if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q
149        || !d1->buffered_messages || !d1->sent_messages
150        || !d1->buffered_app_data.q) {
151        if (d1->unprocessed_rcds.q)
152            pqueue_free(d1->unprocessed_rcds.q);
153        if (d1->processed_rcds.q)
154            pqueue_free(d1->processed_rcds.q);
155        if (d1->buffered_messages)
156            pqueue_free(d1->buffered_messages);
157        if (d1->sent_messages)
158            pqueue_free(d1->sent_messages);
159        if (d1->buffered_app_data.q)
160            pqueue_free(d1->buffered_app_data.q);
161        OPENSSL_free(d1);
162        return (0);
163    }
164
165    s->d1 = d1;
166    s->method->ssl_clear(s);
167    return (1);
168}
169
170static void dtls1_clear_queues(SSL *s)
171{
172    pitem *item = NULL;
173    hm_fragment *frag = NULL;
174    DTLS1_RECORD_DATA *rdata;
175
176    while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) {
177        rdata = (DTLS1_RECORD_DATA *)item->data;
178        if (rdata->rbuf.buf) {
179            OPENSSL_free(rdata->rbuf.buf);
180        }
181        OPENSSL_free(item->data);
182        pitem_free(item);
183    }
184
185    while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
186        rdata = (DTLS1_RECORD_DATA *)item->data;
187        if (rdata->rbuf.buf) {
188            OPENSSL_free(rdata->rbuf.buf);
189        }
190        OPENSSL_free(item->data);
191        pitem_free(item);
192    }
193
194    while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
195        frag = (hm_fragment *)item->data;
196        dtls1_hm_fragment_free(frag);
197        pitem_free(item);
198    }
199
200    while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
201        frag = (hm_fragment *)item->data;
202        dtls1_hm_fragment_free(frag);
203        pitem_free(item);
204    }
205
206    while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) {
207        rdata = (DTLS1_RECORD_DATA *)item->data;
208        if (rdata->rbuf.buf) {
209            OPENSSL_free(rdata->rbuf.buf);
210        }
211        OPENSSL_free(item->data);
212        pitem_free(item);
213    }
214}
215
216void dtls1_free(SSL *s)
217{
218    ssl3_free(s);
219
220    dtls1_clear_queues(s);
221
222    pqueue_free(s->d1->unprocessed_rcds.q);
223    pqueue_free(s->d1->processed_rcds.q);
224    pqueue_free(s->d1->buffered_messages);
225    pqueue_free(s->d1->sent_messages);
226    pqueue_free(s->d1->buffered_app_data.q);
227
228    OPENSSL_free(s->d1);
229    s->d1 = NULL;
230}
231
232void dtls1_clear(SSL *s)
233{
234    pqueue unprocessed_rcds;
235    pqueue processed_rcds;
236    pqueue buffered_messages;
237    pqueue sent_messages;
238    pqueue buffered_app_data;
239    unsigned int mtu;
240    unsigned int link_mtu;
241
242    if (s->d1) {
243        unprocessed_rcds = s->d1->unprocessed_rcds.q;
244        processed_rcds = s->d1->processed_rcds.q;
245        buffered_messages = s->d1->buffered_messages;
246        sent_messages = s->d1->sent_messages;
247        buffered_app_data = s->d1->buffered_app_data.q;
248        mtu = s->d1->mtu;
249        link_mtu = s->d1->link_mtu;
250
251        dtls1_clear_queues(s);
252
253        memset(s->d1, 0, sizeof(*(s->d1)));
254
255        if (s->server) {
256            s->d1->cookie_len = sizeof(s->d1->cookie);
257        }
258
259        if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
260            s->d1->mtu = mtu;
261            s->d1->link_mtu = link_mtu;
262        }
263
264        s->d1->unprocessed_rcds.q = unprocessed_rcds;
265        s->d1->processed_rcds.q = processed_rcds;
266        s->d1->buffered_messages = buffered_messages;
267        s->d1->sent_messages = sent_messages;
268        s->d1->buffered_app_data.q = buffered_app_data;
269    }
270
271    ssl3_clear(s);
272    if (s->options & SSL_OP_CISCO_ANYCONNECT)
273        s->client_version = s->version = DTLS1_BAD_VER;
274    else if (s->method->version == DTLS_ANY_VERSION)
275        s->version = DTLS1_2_VERSION;
276    else
277        s->version = s->method->version;
278}
279
280long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
281{
282    int ret = 0;
283
284    switch (cmd) {
285    case DTLS_CTRL_GET_TIMEOUT:
286        if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
287            ret = 1;
288        }
289        break;
290    case DTLS_CTRL_HANDLE_TIMEOUT:
291        ret = dtls1_handle_timeout(s);
292        break;
293    case DTLS_CTRL_LISTEN:
294        ret = dtls1_listen(s, parg);
295        break;
296    case SSL_CTRL_CHECK_PROTO_VERSION:
297        /*
298         * For library-internal use; checks that the current protocol is the
299         * highest enabled version (according to s->ctx->method, as version
300         * negotiation may have changed s->method).
301         */
302        if (s->version == s->ctx->method->version)
303            return 1;
304        /*
305         * Apparently we're using a version-flexible SSL_METHOD (not at its
306         * highest protocol version).
307         */
308        if (s->ctx->method->version == DTLS_method()->version) {
309#if DTLS_MAX_VERSION != DTLS1_2_VERSION
310# error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
311#endif
312            if (!(s->options & SSL_OP_NO_DTLSv1_2))
313                return s->version == DTLS1_2_VERSION;
314            if (!(s->options & SSL_OP_NO_DTLSv1))
315                return s->version == DTLS1_VERSION;
316        }
317        return 0;               /* Unexpected state; fail closed. */
318    case DTLS_CTRL_SET_LINK_MTU:
319        if (larg < (long)dtls1_link_min_mtu())
320            return 0;
321        s->d1->link_mtu = larg;
322        return 1;
323    case DTLS_CTRL_GET_LINK_MIN_MTU:
324        return (long)dtls1_link_min_mtu();
325    case SSL_CTRL_SET_MTU:
326        /*
327         *  We may not have a BIO set yet so can't call dtls1_min_mtu()
328         *  We'll have to make do with dtls1_link_min_mtu() and max overhead
329         */
330        if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
331            return 0;
332        s->d1->mtu = larg;
333        return larg;
334    default:
335        ret = ssl3_ctrl(s, cmd, larg, parg);
336        break;
337    }
338    return (ret);
339}
340
341/*
342 * As it's impossible to use stream ciphers in "datagram" mode, this
343 * simple filter is designed to disengage them in DTLS. Unfortunately
344 * there is no universal way to identify stream SSL_CIPHER, so we have
345 * to explicitly list their SSL_* codes. Currently RC4 is the only one
346 * available, but if new ones emerge, they will have to be added...
347 */
348const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
349{
350    const SSL_CIPHER *ciph = ssl3_get_cipher(u);
351
352    if (ciph != NULL) {
353        if (ciph->algorithm_enc == SSL_RC4)
354            return NULL;
355    }
356
357    return ciph;
358}
359
360void dtls1_start_timer(SSL *s)
361{
362#ifndef OPENSSL_NO_SCTP
363    /* Disable timer for SCTP */
364    if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
365        memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
366        return;
367    }
368#endif
369
370    /* If timer is not set, initialize duration with 1 second */
371    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
372        s->d1->timeout_duration = 1;
373    }
374
375    /* Set timeout to current time */
376    get_current_time(&(s->d1->next_timeout));
377
378    /* Add duration to current time */
379    s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
380    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
381             &(s->d1->next_timeout));
382}
383
384struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
385{
386    struct timeval timenow;
387
388    /* If no timeout is set, just return NULL */
389    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
390        return NULL;
391    }
392
393    /* Get current time */
394    get_current_time(&timenow);
395
396    /* If timer already expired, set remaining time to 0 */
397    if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
398        (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
399         s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
400        memset(timeleft, 0, sizeof(struct timeval));
401        return timeleft;
402    }
403
404    /* Calculate time left until timer expires */
405    memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
406    timeleft->tv_sec -= timenow.tv_sec;
407    timeleft->tv_usec -= timenow.tv_usec;
408    if (timeleft->tv_usec < 0) {
409        timeleft->tv_sec--;
410        timeleft->tv_usec += 1000000;
411    }
412
413    /*
414     * If remaining time is less than 15 ms, set it to 0 to prevent issues
415     * because of small devergences with socket timeouts.
416     */
417    if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
418        memset(timeleft, 0, sizeof(struct timeval));
419    }
420
421    return timeleft;
422}
423
424int dtls1_is_timer_expired(SSL *s)
425{
426    struct timeval timeleft;
427
428    /* Get time left until timeout, return false if no timer running */
429    if (dtls1_get_timeout(s, &timeleft) == NULL) {
430        return 0;
431    }
432
433    /* Return false if timer is not expired yet */
434    if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
435        return 0;
436    }
437
438    /* Timer expired, so return true */
439    return 1;
440}
441
442void dtls1_double_timeout(SSL *s)
443{
444    s->d1->timeout_duration *= 2;
445    if (s->d1->timeout_duration > 60)
446        s->d1->timeout_duration = 60;
447    dtls1_start_timer(s);
448}
449
450void dtls1_stop_timer(SSL *s)
451{
452    /* Reset everything */
453    memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
454    memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
455    s->d1->timeout_duration = 1;
456    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
457             &(s->d1->next_timeout));
458    /* Clear retransmission buffer */
459    dtls1_clear_record_buffer(s);
460}
461
462int dtls1_check_timeout_num(SSL *s)
463{
464    unsigned int mtu;
465
466    s->d1->timeout.num_alerts++;
467
468    /* Reduce MTU after 2 unsuccessful retransmissions */
469    if (s->d1->timeout.num_alerts > 2
470        && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
471        mtu =
472            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
473                     NULL);
474        if (mtu < s->d1->mtu)
475            s->d1->mtu = mtu;
476    }
477
478    if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
479        /* fail the connection, enough alerts have been sent */
480        SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
481        return -1;
482    }
483
484    return 0;
485}
486
487int dtls1_handle_timeout(SSL *s)
488{
489    /* if no timer is expired, don't do anything */
490    if (!dtls1_is_timer_expired(s)) {
491        return 0;
492    }
493
494    dtls1_double_timeout(s);
495
496    if (dtls1_check_timeout_num(s) < 0)
497        return -1;
498
499    s->d1->timeout.read_timeouts++;
500    if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
501        s->d1->timeout.read_timeouts = 1;
502    }
503#ifndef OPENSSL_NO_HEARTBEATS
504    if (s->tlsext_hb_pending) {
505        s->tlsext_hb_pending = 0;
506        return dtls1_heartbeat(s);
507    }
508#endif
509
510    dtls1_start_timer(s);
511    return dtls1_retransmit_buffered_messages(s);
512}
513
514static void get_current_time(struct timeval *t)
515{
516#if defined(_WIN32)
517    SYSTEMTIME st;
518    union {
519        unsigned __int64 ul;
520        FILETIME ft;
521    } now;
522
523    GetSystemTime(&st);
524    SystemTimeToFileTime(&st, &now.ft);
525# ifdef  __MINGW32__
526    now.ul -= 116444736000000000ULL;
527# else
528    now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
529# endif
530    t->tv_sec = (long)(now.ul / 10000000);
531    t->tv_usec = ((int)(now.ul % 10000000)) / 10;
532#elif defined(OPENSSL_SYS_VMS)
533    struct timeb tb;
534    ftime(&tb);
535    t->tv_sec = (long)tb.time;
536    t->tv_usec = (long)tb.millitm * 1000;
537#else
538    gettimeofday(t, NULL);
539#endif
540}
541
542int dtls1_listen(SSL *s, struct sockaddr *client)
543{
544    int ret;
545
546    /* Ensure there is no state left over from a previous invocation */
547    SSL_clear(s);
548
549    SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
550    s->d1->listen = 1;
551
552    ret = SSL_accept(s);
553    if (ret <= 0)
554        return ret;
555
556    (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
557    return 1;
558}
559
560static void dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
561{
562    unsigned char *p = (unsigned char *)s->init_buf->data;
563    dtls1_set_message_header(s, p, htype, len, 0, len);
564    s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
565    s->init_off = 0;
566    /* Buffer the message to handle re-xmits */
567    dtls1_buffer_message(s, 0);
568}
569
570static int dtls1_handshake_write(SSL *s)
571{
572    return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
573}
574