d1_lib.c revision 306195 
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    DTLS1_RECORD_DATA *rdata;
174
175    while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) {
176        rdata = (DTLS1_RECORD_DATA *)item->data;
177        if (rdata->rbuf.buf) {
178            OPENSSL_free(rdata->rbuf.buf);
179        }
180        OPENSSL_free(item->data);
181        pitem_free(item);
182    }
183
184    while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
185        rdata = (DTLS1_RECORD_DATA *)item->data;
186        if (rdata->rbuf.buf) {
187            OPENSSL_free(rdata->rbuf.buf);
188        }
189        OPENSSL_free(item->data);
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    dtls1_clear_received_buffer(s);
203    dtls1_clear_sent_buffer(s);
204}
205
206void dtls1_clear_received_buffer(SSL *s)
207{
208    pitem *item = NULL;
209    hm_fragment *frag = NULL;
210
211    while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
212        frag = (hm_fragment *)item->data;
213        dtls1_hm_fragment_free(frag);
214        pitem_free(item);
215    }
216}
217
218void dtls1_clear_sent_buffer(SSL *s)
219{
220    pitem *item = NULL;
221    hm_fragment *frag = NULL;
222
223    while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
224        frag = (hm_fragment *)item->data;
225        dtls1_hm_fragment_free(frag);
226        pitem_free(item);
227    }
228}
229
230
231void dtls1_free(SSL *s)
232{
233    ssl3_free(s);
234
235    dtls1_clear_queues(s);
236
237    pqueue_free(s->d1->unprocessed_rcds.q);
238    pqueue_free(s->d1->processed_rcds.q);
239    pqueue_free(s->d1->buffered_messages);
240    pqueue_free(s->d1->sent_messages);
241    pqueue_free(s->d1->buffered_app_data.q);
242
243    OPENSSL_free(s->d1);
244    s->d1 = NULL;
245}
246
247void dtls1_clear(SSL *s)
248{
249    pqueue unprocessed_rcds;
250    pqueue processed_rcds;
251    pqueue buffered_messages;
252    pqueue sent_messages;
253    pqueue buffered_app_data;
254    unsigned int mtu;
255    unsigned int link_mtu;
256
257    if (s->d1) {
258        unprocessed_rcds = s->d1->unprocessed_rcds.q;
259        processed_rcds = s->d1->processed_rcds.q;
260        buffered_messages = s->d1->buffered_messages;
261        sent_messages = s->d1->sent_messages;
262        buffered_app_data = s->d1->buffered_app_data.q;
263        mtu = s->d1->mtu;
264        link_mtu = s->d1->link_mtu;
265
266        dtls1_clear_queues(s);
267
268        memset(s->d1, 0, sizeof(*(s->d1)));
269
270        if (s->server) {
271            s->d1->cookie_len = sizeof(s->d1->cookie);
272        }
273
274        if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
275            s->d1->mtu = mtu;
276            s->d1->link_mtu = link_mtu;
277        }
278
279        s->d1->unprocessed_rcds.q = unprocessed_rcds;
280        s->d1->processed_rcds.q = processed_rcds;
281        s->d1->buffered_messages = buffered_messages;
282        s->d1->sent_messages = sent_messages;
283        s->d1->buffered_app_data.q = buffered_app_data;
284    }
285
286    ssl3_clear(s);
287    if (s->options & SSL_OP_CISCO_ANYCONNECT)
288        s->client_version = s->version = DTLS1_BAD_VER;
289    else if (s->method->version == DTLS_ANY_VERSION)
290        s->version = DTLS1_2_VERSION;
291    else
292        s->version = s->method->version;
293}
294
295long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
296{
297    int ret = 0;
298
299    switch (cmd) {
300    case DTLS_CTRL_GET_TIMEOUT:
301        if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
302            ret = 1;
303        }
304        break;
305    case DTLS_CTRL_HANDLE_TIMEOUT:
306        ret = dtls1_handle_timeout(s);
307        break;
308    case DTLS_CTRL_LISTEN:
309        ret = dtls1_listen(s, parg);
310        break;
311    case SSL_CTRL_CHECK_PROTO_VERSION:
312        /*
313         * For library-internal use; checks that the current protocol is the
314         * highest enabled version (according to s->ctx->method, as version
315         * negotiation may have changed s->method).
316         */
317        if (s->version == s->ctx->method->version)
318            return 1;
319        /*
320         * Apparently we're using a version-flexible SSL_METHOD (not at its
321         * highest protocol version).
322         */
323        if (s->ctx->method->version == DTLS_method()->version) {
324#if DTLS_MAX_VERSION != DTLS1_2_VERSION
325# error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
326#endif
327            if (!(s->options & SSL_OP_NO_DTLSv1_2))
328                return s->version == DTLS1_2_VERSION;
329            if (!(s->options & SSL_OP_NO_DTLSv1))
330                return s->version == DTLS1_VERSION;
331        }
332        return 0;               /* Unexpected state; fail closed. */
333    case DTLS_CTRL_SET_LINK_MTU:
334        if (larg < (long)dtls1_link_min_mtu())
335            return 0;
336        s->d1->link_mtu = larg;
337        return 1;
338    case DTLS_CTRL_GET_LINK_MIN_MTU:
339        return (long)dtls1_link_min_mtu();
340    case SSL_CTRL_SET_MTU:
341        /*
342         *  We may not have a BIO set yet so can't call dtls1_min_mtu()
343         *  We'll have to make do with dtls1_link_min_mtu() and max overhead
344         */
345        if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
346            return 0;
347        s->d1->mtu = larg;
348        return larg;
349    default:
350        ret = ssl3_ctrl(s, cmd, larg, parg);
351        break;
352    }
353    return (ret);
354}
355
356/*
357 * As it's impossible to use stream ciphers in "datagram" mode, this
358 * simple filter is designed to disengage them in DTLS. Unfortunately
359 * there is no universal way to identify stream SSL_CIPHER, so we have
360 * to explicitly list their SSL_* codes. Currently RC4 is the only one
361 * available, but if new ones emerge, they will have to be added...
362 */
363const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
364{
365    const SSL_CIPHER *ciph = ssl3_get_cipher(u);
366
367    if (ciph != NULL) {
368        if (ciph->algorithm_enc == SSL_RC4)
369            return NULL;
370    }
371
372    return ciph;
373}
374
375void dtls1_start_timer(SSL *s)
376{
377#ifndef OPENSSL_NO_SCTP
378    /* Disable timer for SCTP */
379    if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
380        memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
381        return;
382    }
383#endif
384
385    /* If timer is not set, initialize duration with 1 second */
386    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
387        s->d1->timeout_duration = 1;
388    }
389
390    /* Set timeout to current time */
391    get_current_time(&(s->d1->next_timeout));
392
393    /* Add duration to current time */
394    s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
395    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
396             &(s->d1->next_timeout));
397}
398
399struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
400{
401    struct timeval timenow;
402
403    /* If no timeout is set, just return NULL */
404    if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
405        return NULL;
406    }
407
408    /* Get current time */
409    get_current_time(&timenow);
410
411    /* If timer already expired, set remaining time to 0 */
412    if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
413        (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
414         s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
415        memset(timeleft, 0, sizeof(struct timeval));
416        return timeleft;
417    }
418
419    /* Calculate time left until timer expires */
420    memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
421    timeleft->tv_sec -= timenow.tv_sec;
422    timeleft->tv_usec -= timenow.tv_usec;
423    if (timeleft->tv_usec < 0) {
424        timeleft->tv_sec--;
425        timeleft->tv_usec += 1000000;
426    }
427
428    /*
429     * If remaining time is less than 15 ms, set it to 0 to prevent issues
430     * because of small devergences with socket timeouts.
431     */
432    if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
433        memset(timeleft, 0, sizeof(struct timeval));
434    }
435
436    return timeleft;
437}
438
439int dtls1_is_timer_expired(SSL *s)
440{
441    struct timeval timeleft;
442
443    /* Get time left until timeout, return false if no timer running */
444    if (dtls1_get_timeout(s, &timeleft) == NULL) {
445        return 0;
446    }
447
448    /* Return false if timer is not expired yet */
449    if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
450        return 0;
451    }
452
453    /* Timer expired, so return true */
454    return 1;
455}
456
457void dtls1_double_timeout(SSL *s)
458{
459    s->d1->timeout_duration *= 2;
460    if (s->d1->timeout_duration > 60)
461        s->d1->timeout_duration = 60;
462    dtls1_start_timer(s);
463}
464
465void dtls1_stop_timer(SSL *s)
466{
467    /* Reset everything */
468    memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
469    memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
470    s->d1->timeout_duration = 1;
471    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
472             &(s->d1->next_timeout));
473    /* Clear retransmission buffer */
474    dtls1_clear_sent_buffer(s);
475}
476
477int dtls1_check_timeout_num(SSL *s)
478{
479    unsigned int mtu;
480
481    s->d1->timeout.num_alerts++;
482
483    /* Reduce MTU after 2 unsuccessful retransmissions */
484    if (s->d1->timeout.num_alerts > 2
485        && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
486        mtu =
487            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
488                     NULL);
489        if (mtu < s->d1->mtu)
490            s->d1->mtu = mtu;
491    }
492
493    if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
494        /* fail the connection, enough alerts have been sent */
495        SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
496        return -1;
497    }
498
499    return 0;
500}
501
502int dtls1_handle_timeout(SSL *s)
503{
504    /* if no timer is expired, don't do anything */
505    if (!dtls1_is_timer_expired(s)) {
506        return 0;
507    }
508
509    dtls1_double_timeout(s);
510
511    if (dtls1_check_timeout_num(s) < 0)
512        return -1;
513
514    s->d1->timeout.read_timeouts++;
515    if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
516        s->d1->timeout.read_timeouts = 1;
517    }
518#ifndef OPENSSL_NO_HEARTBEATS
519    if (s->tlsext_hb_pending) {
520        s->tlsext_hb_pending = 0;
521        return dtls1_heartbeat(s);
522    }
523#endif
524
525    dtls1_start_timer(s);
526    return dtls1_retransmit_buffered_messages(s);
527}
528
529static void get_current_time(struct timeval *t)
530{
531#if defined(_WIN32)
532    SYSTEMTIME st;
533    union {
534        unsigned __int64 ul;
535        FILETIME ft;
536    } now;
537
538    GetSystemTime(&st);
539    SystemTimeToFileTime(&st, &now.ft);
540# ifdef  __MINGW32__
541    now.ul -= 116444736000000000ULL;
542# else
543    now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
544# endif
545    t->tv_sec = (long)(now.ul / 10000000);
546    t->tv_usec = ((int)(now.ul % 10000000)) / 10;
547#elif defined(OPENSSL_SYS_VMS)
548    struct timeb tb;
549    ftime(&tb);
550    t->tv_sec = (long)tb.time;
551    t->tv_usec = (long)tb.millitm * 1000;
552#else
553    gettimeofday(t, NULL);
554#endif
555}
556
557int dtls1_listen(SSL *s, struct sockaddr *client)
558{
559    int ret;
560
561    /* Ensure there is no state left over from a previous invocation */
562    SSL_clear(s);
563
564    SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
565    s->d1->listen = 1;
566
567    ret = SSL_accept(s);
568    if (ret <= 0)
569        return ret;
570
571    (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
572    return 1;
573}
574
575static void dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
576{
577    unsigned char *p = (unsigned char *)s->init_buf->data;
578    dtls1_set_message_header(s, p, htype, len, 0, len);
579    s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
580    s->init_off = 0;
581    /* Buffer the message to handle re-xmits */
582    dtls1_buffer_message(s, 0);
583}
584
585static int dtls1_handshake_write(SSL *s)
586{
587    return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
588}
589