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Commit | Line | Data |
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0f113f3e | 1 | /* |
c486283c | 2 | * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved. |
36d16f8e | 3 | * |
2c18d164 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
846e33c7 RS |
5 | * this file except in compliance with the License. You can obtain a copy |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
36d16f8e BL |
8 | */ |
9 | ||
07016a8a | 10 | #include "e_os.h" |
36d16f8e BL |
11 | #include <stdio.h> |
12 | #include <openssl/objects.h> | |
8ba708e5 | 13 | #include <openssl/rand.h> |
36d16f8e BL |
14 | #include "ssl_locl.h" |
15 | ||
eb38b26d | 16 | static void get_current_time(struct timeval *t); |
173e72e6 | 17 | static int dtls1_handshake_write(SSL *s); |
7ee8627f | 18 | static size_t dtls1_link_min_mtu(void); |
36d16f8e | 19 | |
8ba708e5 | 20 | /* XDTLS: figure out the right values */ |
7ee8627f | 21 | static const size_t g_probable_mtu[] = { 1500, 512, 256 }; |
8ba708e5 | 22 | |
0f113f3e MC |
23 | const SSL3_ENC_METHOD DTLSv1_enc_data = { |
24 | tls1_enc, | |
25 | tls1_mac, | |
26 | tls1_setup_key_block, | |
27 | tls1_generate_master_secret, | |
28 | tls1_change_cipher_state, | |
29 | tls1_final_finish_mac, | |
0f113f3e MC |
30 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, |
31 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, | |
32 | tls1_alert_code, | |
33 | tls1_export_keying_material, | |
34 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV, | |
a29fa98c | 35 | dtls1_set_handshake_header, |
2c7b4dbc | 36 | dtls1_close_construct_packet, |
0f113f3e MC |
37 | dtls1_handshake_write |
38 | }; | |
39 | ||
40 | const SSL3_ENC_METHOD DTLSv1_2_enc_data = { | |
41 | tls1_enc, | |
42 | tls1_mac, | |
43 | tls1_setup_key_block, | |
44 | tls1_generate_master_secret, | |
45 | tls1_change_cipher_state, | |
46 | tls1_final_finish_mac, | |
0f113f3e MC |
47 | TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, |
48 | TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, | |
49 | tls1_alert_code, | |
50 | tls1_export_keying_material, | |
51 | SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS | |
52 | | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS, | |
a29fa98c | 53 | dtls1_set_handshake_header, |
2c7b4dbc | 54 | dtls1_close_construct_packet, |
0f113f3e MC |
55 | dtls1_handshake_write |
56 | }; | |
c3b344e3 | 57 | |
f3b656b2 | 58 | long dtls1_default_timeout(void) |
0f113f3e MC |
59 | { |
60 | /* | |
61 | * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for | |
62 | * http, the cache would over fill | |
63 | */ | |
64 | return (60 * 60 * 2); | |
65 | } | |
36d16f8e | 66 | |
36d16f8e | 67 | int dtls1_new(SSL *s) |
0f113f3e MC |
68 | { |
69 | DTLS1_STATE *d1; | |
70 | ||
61986d32 | 71 | if (!DTLS_RECORD_LAYER_new(&s->rlayer)) { |
5fb6f80c MC |
72 | return 0; |
73 | } | |
0485d540 | 74 | |
0f113f3e | 75 | if (!ssl3_new(s)) |
a89325e4 | 76 | return 0; |
b51bce94 | 77 | if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) { |
0f113f3e | 78 | ssl3_free(s); |
a89325e4 | 79 | return 0; |
0f113f3e | 80 | } |
0f113f3e | 81 | |
0f113f3e MC |
82 | d1->buffered_messages = pqueue_new(); |
83 | d1->sent_messages = pqueue_new(); | |
0f113f3e MC |
84 | |
85 | if (s->server) { | |
86 | d1->cookie_len = sizeof(s->d1->cookie); | |
87 | } | |
88 | ||
89 | d1->link_mtu = 0; | |
90 | d1->mtu = 0; | |
91 | ||
a71edf3b | 92 | if (d1->buffered_messages == NULL || d1->sent_messages == NULL) { |
25aaa98a RS |
93 | pqueue_free(d1->buffered_messages); |
94 | pqueue_free(d1->sent_messages); | |
0f113f3e MC |
95 | OPENSSL_free(d1); |
96 | ssl3_free(s); | |
a89325e4 | 97 | return 0; |
0f113f3e MC |
98 | } |
99 | ||
100 | s->d1 = d1; | |
b77f3ed1 MC |
101 | |
102 | if (!s->method->ssl_clear(s)) | |
103 | return 0; | |
104 | ||
a89325e4 | 105 | return 1; |
0f113f3e | 106 | } |
36d16f8e | 107 | |
7832d6ab | 108 | static void dtls1_clear_queues(SSL *s) |
f5c7f5df MC |
109 | { |
110 | dtls1_clear_received_buffer(s); | |
111 | dtls1_clear_sent_buffer(s); | |
112 | } | |
113 | ||
114 | void dtls1_clear_received_buffer(SSL *s) | |
0f113f3e | 115 | { |
36d16f8e BL |
116 | pitem *item = NULL; |
117 | hm_fragment *frag = NULL; | |
0f113f3e | 118 | |
0f113f3e | 119 | while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) { |
36d16f8e | 120 | frag = (hm_fragment *)item->data; |
8a35dbb6 | 121 | dtls1_hm_fragment_free(frag); |
36d16f8e | 122 | pitem_free(item); |
0f113f3e | 123 | } |
f5c7f5df MC |
124 | } |
125 | ||
126 | void dtls1_clear_sent_buffer(SSL *s) | |
127 | { | |
128 | pitem *item = NULL; | |
129 | hm_fragment *frag = NULL; | |
36d16f8e | 130 | |
0f113f3e | 131 | while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { |
36d16f8e | 132 | frag = (hm_fragment *)item->data; |
8a35dbb6 | 133 | dtls1_hm_fragment_free(frag); |
36d16f8e | 134 | pitem_free(item); |
0f113f3e | 135 | } |
0f113f3e | 136 | } |
7832d6ab | 137 | |
f5c7f5df | 138 | |
7832d6ab | 139 | void dtls1_free(SSL *s) |
0f113f3e | 140 | { |
40f37188 MC |
141 | DTLS_RECORD_LAYER_free(&s->rlayer); |
142 | ||
0f113f3e | 143 | ssl3_free(s); |
7832d6ab | 144 | |
0f113f3e | 145 | dtls1_clear_queues(s); |
7832d6ab | 146 | |
7832d6ab | 147 | pqueue_free(s->d1->buffered_messages); |
0f113f3e | 148 | pqueue_free(s->d1->sent_messages); |
e5fa864f | 149 | |
0f113f3e MC |
150 | OPENSSL_free(s->d1); |
151 | s->d1 = NULL; | |
152 | } | |
36d16f8e | 153 | |
b77f3ed1 | 154 | int dtls1_clear(SSL *s) |
0f113f3e | 155 | { |
cf2cede4 RS |
156 | pqueue *buffered_messages; |
157 | pqueue *sent_messages; | |
7ee8627f MC |
158 | size_t mtu; |
159 | size_t link_mtu; | |
0f113f3e | 160 | |
40f37188 MC |
161 | DTLS_RECORD_LAYER_clear(&s->rlayer); |
162 | ||
0f113f3e | 163 | if (s->d1) { |
fa4b82cc AH |
164 | DTLS_timer_cb timer_cb = s->d1->timer_cb; |
165 | ||
0f113f3e MC |
166 | buffered_messages = s->d1->buffered_messages; |
167 | sent_messages = s->d1->sent_messages; | |
0f113f3e MC |
168 | mtu = s->d1->mtu; |
169 | link_mtu = s->d1->link_mtu; | |
170 | ||
171 | dtls1_clear_queues(s); | |
172 | ||
16f8d4eb | 173 | memset(s->d1, 0, sizeof(*s->d1)); |
0f113f3e | 174 | |
fa4b82cc AH |
175 | /* Restore the timer callback from previous state */ |
176 | s->d1->timer_cb = timer_cb; | |
177 | ||
0f113f3e MC |
178 | if (s->server) { |
179 | s->d1->cookie_len = sizeof(s->d1->cookie); | |
180 | } | |
181 | ||
182 | if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { | |
183 | s->d1->mtu = mtu; | |
184 | s->d1->link_mtu = link_mtu; | |
185 | } | |
186 | ||
0f113f3e MC |
187 | s->d1->buffered_messages = buffered_messages; |
188 | s->d1->sent_messages = sent_messages; | |
0f113f3e MC |
189 | } |
190 | ||
b77f3ed1 MC |
191 | if (!ssl3_clear(s)) |
192 | return 0; | |
032924c4 DW |
193 | |
194 | if (s->method->version == DTLS_ANY_VERSION) | |
5c587fb6 | 195 | s->version = DTLS_MAX_VERSION_INTERNAL; |
032924c4 DW |
196 | #ifndef OPENSSL_NO_DTLS1_METHOD |
197 | else if (s->options & SSL_OP_CISCO_ANYCONNECT) | |
198 | s->client_version = s->version = DTLS1_BAD_VER; | |
199 | #endif | |
0f113f3e MC |
200 | else |
201 | s->version = s->method->version; | |
b77f3ed1 MC |
202 | |
203 | return 1; | |
0f113f3e | 204 | } |
5d58f1bb | 205 | |
b972fbaa | 206 | long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) |
0f113f3e MC |
207 | { |
208 | int ret = 0; | |
209 | ||
210 | switch (cmd) { | |
211 | case DTLS_CTRL_GET_TIMEOUT: | |
212 | if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) { | |
213 | ret = 1; | |
214 | } | |
215 | break; | |
216 | case DTLS_CTRL_HANDLE_TIMEOUT: | |
217 | ret = dtls1_handle_timeout(s); | |
218 | break; | |
0f113f3e MC |
219 | case DTLS_CTRL_SET_LINK_MTU: |
220 | if (larg < (long)dtls1_link_min_mtu()) | |
221 | return 0; | |
222 | s->d1->link_mtu = larg; | |
223 | return 1; | |
224 | case DTLS_CTRL_GET_LINK_MIN_MTU: | |
225 | return (long)dtls1_link_min_mtu(); | |
226 | case SSL_CTRL_SET_MTU: | |
227 | /* | |
228 | * We may not have a BIO set yet so can't call dtls1_min_mtu() | |
229 | * We'll have to make do with dtls1_link_min_mtu() and max overhead | |
230 | */ | |
231 | if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD) | |
232 | return 0; | |
233 | s->d1->mtu = larg; | |
234 | return larg; | |
235 | default: | |
236 | ret = ssl3_ctrl(s, cmd, larg, parg); | |
237 | break; | |
238 | } | |
26a7d938 | 239 | return ret; |
0f113f3e | 240 | } |
b972fbaa | 241 | |
eb38b26d | 242 | void dtls1_start_timer(SSL *s) |
0f113f3e | 243 | { |
fa4b82cc AH |
244 | unsigned int sec, usec; |
245 | ||
7e159e01 | 246 | #ifndef OPENSSL_NO_SCTP |
0f113f3e MC |
247 | /* Disable timer for SCTP */ |
248 | if (BIO_dgram_is_sctp(SSL_get_wbio(s))) { | |
16f8d4eb | 249 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); |
0f113f3e MC |
250 | return; |
251 | } | |
7e159e01 DSH |
252 | #endif |
253 | ||
fa4b82cc AH |
254 | /* |
255 | * If timer is not set, initialize duration with 1 second or | |
256 | * a user-specified value if the timer callback is installed. | |
257 | */ | |
0f113f3e | 258 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { |
fa4b82cc AH |
259 | |
260 | if (s->d1->timer_cb != NULL) | |
261 | s->d1->timeout_duration_us = s->d1->timer_cb(s, 0); | |
262 | else | |
263 | s->d1->timeout_duration_us = 1000000; | |
0f113f3e MC |
264 | } |
265 | ||
266 | /* Set timeout to current time */ | |
267 | get_current_time(&(s->d1->next_timeout)); | |
268 | ||
269 | /* Add duration to current time */ | |
fa4b82cc AH |
270 | |
271 | sec = s->d1->timeout_duration_us / 1000000; | |
272 | usec = s->d1->timeout_duration_us - (sec * 1000000); | |
273 | ||
274 | s->d1->next_timeout.tv_sec += sec; | |
275 | s->d1->next_timeout.tv_usec += usec; | |
276 | ||
277 | if (s->d1->next_timeout.tv_usec >= 1000000) { | |
278 | s->d1->next_timeout.tv_sec++; | |
279 | s->d1->next_timeout.tv_usec -= 1000000; | |
280 | } | |
281 | ||
0f113f3e MC |
282 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, |
283 | &(s->d1->next_timeout)); | |
284 | } | |
285 | ||
286 | struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft) | |
287 | { | |
288 | struct timeval timenow; | |
289 | ||
290 | /* If no timeout is set, just return NULL */ | |
291 | if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { | |
292 | return NULL; | |
293 | } | |
294 | ||
295 | /* Get current time */ | |
296 | get_current_time(&timenow); | |
297 | ||
298 | /* If timer already expired, set remaining time to 0 */ | |
299 | if (s->d1->next_timeout.tv_sec < timenow.tv_sec || | |
300 | (s->d1->next_timeout.tv_sec == timenow.tv_sec && | |
301 | s->d1->next_timeout.tv_usec <= timenow.tv_usec)) { | |
16f8d4eb | 302 | memset(timeleft, 0, sizeof(*timeleft)); |
0f113f3e MC |
303 | return timeleft; |
304 | } | |
305 | ||
306 | /* Calculate time left until timer expires */ | |
307 | memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval)); | |
308 | timeleft->tv_sec -= timenow.tv_sec; | |
309 | timeleft->tv_usec -= timenow.tv_usec; | |
310 | if (timeleft->tv_usec < 0) { | |
311 | timeleft->tv_sec--; | |
312 | timeleft->tv_usec += 1000000; | |
313 | } | |
314 | ||
315 | /* | |
316 | * If remaining time is less than 15 ms, set it to 0 to prevent issues | |
f430ba31 | 317 | * because of small divergences with socket timeouts. |
0f113f3e MC |
318 | */ |
319 | if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) { | |
16f8d4eb | 320 | memset(timeleft, 0, sizeof(*timeleft)); |
0f113f3e MC |
321 | } |
322 | ||
323 | return timeleft; | |
324 | } | |
eb38b26d DSH |
325 | |
326 | int dtls1_is_timer_expired(SSL *s) | |
0f113f3e MC |
327 | { |
328 | struct timeval timeleft; | |
eb38b26d | 329 | |
0f113f3e MC |
330 | /* Get time left until timeout, return false if no timer running */ |
331 | if (dtls1_get_timeout(s, &timeleft) == NULL) { | |
332 | return 0; | |
333 | } | |
eb38b26d | 334 | |
0f113f3e MC |
335 | /* Return false if timer is not expired yet */ |
336 | if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) { | |
337 | return 0; | |
338 | } | |
eb38b26d | 339 | |
0f113f3e MC |
340 | /* Timer expired, so return true */ |
341 | return 1; | |
342 | } | |
eb38b26d DSH |
343 | |
344 | void dtls1_double_timeout(SSL *s) | |
0f113f3e | 345 | { |
fa4b82cc AH |
346 | s->d1->timeout_duration_us *= 2; |
347 | if (s->d1->timeout_duration_us > 60000000) | |
348 | s->d1->timeout_duration_us = 60000000; | |
0f113f3e MC |
349 | dtls1_start_timer(s); |
350 | } | |
eb38b26d DSH |
351 | |
352 | void dtls1_stop_timer(SSL *s) | |
0f113f3e MC |
353 | { |
354 | /* Reset everything */ | |
16f8d4eb RS |
355 | memset(&s->d1->timeout, 0, sizeof(s->d1->timeout)); |
356 | memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); | |
fa4b82cc | 357 | s->d1->timeout_duration_us = 1000000; |
0f113f3e MC |
358 | BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, |
359 | &(s->d1->next_timeout)); | |
360 | /* Clear retransmission buffer */ | |
f5c7f5df | 361 | dtls1_clear_sent_buffer(s); |
0f113f3e | 362 | } |
eb38b26d | 363 | |
ea6e3860 | 364 | int dtls1_check_timeout_num(SSL *s) |
0f113f3e | 365 | { |
7ee8627f | 366 | size_t mtu; |
0f113f3e MC |
367 | |
368 | s->d1->timeout.num_alerts++; | |
369 | ||
370 | /* Reduce MTU after 2 unsuccessful retransmissions */ | |
371 | if (s->d1->timeout.num_alerts > 2 | |
372 | && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { | |
373 | mtu = | |
a230b26e | 374 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); |
0f113f3e MC |
375 | if (mtu < s->d1->mtu) |
376 | s->d1->mtu = mtu; | |
377 | } | |
378 | ||
379 | if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) { | |
380 | /* fail the connection, enough alerts have been sent */ | |
c2853382 MC |
381 | SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_DTLS1_CHECK_TIMEOUT_NUM, |
382 | SSL_R_READ_TIMEOUT_EXPIRED); | |
0f113f3e MC |
383 | return -1; |
384 | } | |
385 | ||
386 | return 0; | |
387 | } | |
ea6e3860 DSH |
388 | |
389 | int dtls1_handle_timeout(SSL *s) | |
0f113f3e MC |
390 | { |
391 | /* if no timer is expired, don't do anything */ | |
392 | if (!dtls1_is_timer_expired(s)) { | |
393 | return 0; | |
394 | } | |
ea6e3860 | 395 | |
fa4b82cc AH |
396 | if (s->d1->timer_cb != NULL) |
397 | s->d1->timeout_duration_us = s->d1->timer_cb(s, s->d1->timeout_duration_us); | |
398 | else | |
399 | dtls1_double_timeout(s); | |
ea6e3860 | 400 | |
c2853382 MC |
401 | if (dtls1_check_timeout_num(s) < 0) { |
402 | /* SSLfatal() already called */ | |
0f113f3e | 403 | return -1; |
c2853382 | 404 | } |
62b6948a | 405 | |
0f113f3e MC |
406 | s->d1->timeout.read_timeouts++; |
407 | if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) { | |
408 | s->d1->timeout.read_timeouts = 1; | |
409 | } | |
4817504d | 410 | |
0f113f3e | 411 | dtls1_start_timer(s); |
c2853382 | 412 | /* Calls SSLfatal() if required */ |
0f113f3e MC |
413 | return dtls1_retransmit_buffered_messages(s); |
414 | } | |
b972fbaa | 415 | |
eb38b26d DSH |
416 | static void get_current_time(struct timeval *t) |
417 | { | |
a006fef7 | 418 | #if defined(_WIN32) |
0f113f3e MC |
419 | SYSTEMTIME st; |
420 | union { | |
421 | unsigned __int64 ul; | |
422 | FILETIME ft; | |
423 | } now; | |
424 | ||
425 | GetSystemTime(&st); | |
426 | SystemTimeToFileTime(&st, &now.ft); | |
a230b26e | 427 | /* re-bias to 1/1/1970 */ |
0f113f3e MC |
428 | # ifdef __MINGW32__ |
429 | now.ul -= 116444736000000000ULL; | |
430 | # else | |
a230b26e EK |
431 | /* *INDENT-OFF* */ |
432 | now.ul -= 116444736000000000UI64; | |
433 | /* *INDENT-ON* */ | |
0f113f3e MC |
434 | # endif |
435 | t->tv_sec = (long)(now.ul / 10000000); | |
436 | t->tv_usec = ((int)(now.ul % 10000000)) / 10; | |
eb38b26d | 437 | #else |
0f113f3e | 438 | gettimeofday(t, NULL); |
eb38b26d DSH |
439 | #endif |
440 | } | |
1fc3ac80 | 441 | |
e3d0dae7 MC |
442 | #define LISTEN_SUCCESS 2 |
443 | #define LISTEN_SEND_VERIFY_REQUEST 1 | |
444 | ||
f9e55034 | 445 | #ifndef OPENSSL_NO_SOCK |
3edeb622 | 446 | int DTLSv1_listen(SSL *s, BIO_ADDR *client) |
0f113f3e | 447 | { |
079ef6bd | 448 | int next, n, ret = 0; |
e3d0dae7 MC |
449 | unsigned char cookie[DTLS1_COOKIE_LENGTH]; |
450 | unsigned char seq[SEQ_NUM_SIZE]; | |
b6981744 | 451 | const unsigned char *data; |
2fc4c77c | 452 | unsigned char *buf, *wbuf; |
079ef6bd | 453 | size_t fragoff, fraglen, msglen, reclen, align = 0; |
e3d0dae7 MC |
454 | unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen; |
455 | BIO *rbio, *wbio; | |
d858c876 | 456 | BIO_ADDR *tmpclient = NULL; |
e3d0dae7 | 457 | PACKET pkt, msgpkt, msgpayload, session, cookiepkt; |
0f113f3e | 458 | |
5bdcd362 MC |
459 | if (s->handshake_func == NULL) { |
460 | /* Not properly initialized yet */ | |
461 | SSL_set_accept_state(s); | |
462 | } | |
463 | ||
e83ee04b | 464 | /* Ensure there is no state left over from a previous invocation */ |
61986d32 | 465 | if (!SSL_clear(s)) |
c7f5b5d7 | 466 | return -1; |
e83ee04b | 467 | |
e3d0dae7 MC |
468 | ERR_clear_error(); |
469 | ||
470 | rbio = SSL_get_rbio(s); | |
471 | wbio = SSL_get_wbio(s); | |
472 | ||
e8aa8b6c | 473 | if (!rbio || !wbio) { |
3edeb622 | 474 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET); |
e3d0dae7 MC |
475 | return -1; |
476 | } | |
477 | ||
e3d0dae7 MC |
478 | /* |
479 | * Note: This check deliberately excludes DTLS1_BAD_VER because that version | |
480 | * requires the MAC to be calculated *including* the first ClientHello | |
481 | * (without the cookie). Since DTLSv1_listen is stateless that cannot be | |
482 | * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via | |
483 | * SSL_accept) | |
484 | */ | |
485 | if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) { | |
3edeb622 | 486 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION); |
e3d0dae7 MC |
487 | return -1; |
488 | } | |
489 | ||
2fc4c77c MC |
490 | if (!ssl3_setup_buffers(s)) { |
491 | /* SSLerr already called */ | |
492 | return -1; | |
e3d0dae7 | 493 | } |
2fc4c77c MC |
494 | buf = RECORD_LAYER_get_rbuf(&s->rlayer)->buf; |
495 | wbuf = RECORD_LAYER_get_wbuf(&s->rlayer)[0].buf; | |
079ef6bd MC |
496 | #if defined(SSL3_ALIGN_PAYLOAD) |
497 | # if SSL3_ALIGN_PAYLOAD != 0 | |
498 | /* | |
499 | * Using SSL3_RT_HEADER_LENGTH here instead of DTLS1_RT_HEADER_LENGTH for | |
500 | * consistency with ssl3_read_n. In practice it should make no difference | |
501 | * for sensible values of SSL3_ALIGN_PAYLOAD because the difference between | |
502 | * SSL3_RT_HEADER_LENGTH and DTLS1_RT_HEADER_LENGTH is exactly 8 | |
503 | */ | |
504 | align = (size_t)buf + SSL3_RT_HEADER_LENGTH; | |
505 | align = SSL3_ALIGN_PAYLOAD - 1 - ((align - 1) % SSL3_ALIGN_PAYLOAD); | |
506 | # endif | |
507 | #endif | |
508 | buf += align; | |
e3d0dae7 MC |
509 | |
510 | do { | |
511 | /* Get a packet */ | |
512 | ||
513 | clear_sys_error(); | |
2fc4c77c MC |
514 | n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH |
515 | + DTLS1_RT_HEADER_LENGTH); | |
e3d0dae7 | 516 | if (n <= 0) { |
e8aa8b6c | 517 | if (BIO_should_retry(rbio)) { |
e3d0dae7 MC |
518 | /* Non-blocking IO */ |
519 | goto end; | |
520 | } | |
521 | return -1; | |
522 | } | |
523 | ||
e3d0dae7 | 524 | if (!PACKET_buf_init(&pkt, buf, n)) { |
3edeb622 | 525 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); |
e3d0dae7 MC |
526 | return -1; |
527 | } | |
528 | ||
529 | /* | |
530 | * Parse the received record. If there are any problems with it we just | |
531 | * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is | |
532 | * resilient in the face of invalid records (e.g., invalid formatting, | |
533 | * length, MAC, etc.). In general, invalid records SHOULD be silently | |
534 | * discarded, thus preserving the association; however, an error MAY be | |
535 | * logged for diagnostic purposes." | |
536 | */ | |
537 | ||
538 | /* this packet contained a partial record, dump it */ | |
539 | if (n < DTLS1_RT_HEADER_LENGTH) { | |
3edeb622 | 540 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL); |
e3d0dae7 MC |
541 | goto end; |
542 | } | |
543 | ||
544 | if (s->msg_callback) | |
545 | s->msg_callback(0, 0, SSL3_RT_HEADER, buf, | |
546 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); | |
547 | ||
548 | /* Get the record header */ | |
549 | if (!PACKET_get_1(&pkt, &rectype) | |
550 | || !PACKET_get_1(&pkt, &versmajor)) { | |
3edeb622 | 551 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
e3d0dae7 MC |
552 | goto end; |
553 | } | |
554 | ||
a230b26e | 555 | if (rectype != SSL3_RT_HANDSHAKE) { |
3edeb622 | 556 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
e3d0dae7 MC |
557 | goto end; |
558 | } | |
559 | ||
560 | /* | |
561 | * Check record version number. We only check that the major version is | |
562 | * the same. | |
563 | */ | |
564 | if (versmajor != DTLS1_VERSION_MAJOR) { | |
3edeb622 | 565 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); |
e3d0dae7 MC |
566 | goto end; |
567 | } | |
568 | ||
569 | if (!PACKET_forward(&pkt, 1) | |
570 | /* Save the sequence number: 64 bits, with top 2 bytes = epoch */ | |
571 | || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE) | |
4b1043ef | 572 | || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) { |
3edeb622 | 573 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
e3d0dae7 MC |
574 | goto end; |
575 | } | |
079ef6bd | 576 | reclen = PACKET_remaining(&msgpkt); |
4b1043ef MC |
577 | /* |
578 | * We allow data remaining at the end of the packet because there could | |
579 | * be a second record (but we ignore it) | |
580 | */ | |
e3d0dae7 MC |
581 | |
582 | /* This is an initial ClientHello so the epoch has to be 0 */ | |
583 | if (seq[0] != 0 || seq[1] != 0) { | |
3edeb622 | 584 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
e3d0dae7 MC |
585 | goto end; |
586 | } | |
587 | ||
588 | /* Get a pointer to the raw message for the later callback */ | |
589 | data = PACKET_data(&msgpkt); | |
590 | ||
591 | /* Finished processing the record header, now process the message */ | |
592 | if (!PACKET_get_1(&msgpkt, &msgtype) | |
153703df | 593 | || !PACKET_get_net_3_len(&msgpkt, &msglen) |
e3d0dae7 | 594 | || !PACKET_get_net_2(&msgpkt, &msgseq) |
153703df MC |
595 | || !PACKET_get_net_3_len(&msgpkt, &fragoff) |
596 | || !PACKET_get_net_3_len(&msgpkt, &fraglen) | |
4b1043ef | 597 | || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen) |
e3d0dae7 | 598 | || PACKET_remaining(&msgpkt) != 0) { |
3edeb622 | 599 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
e3d0dae7 MC |
600 | goto end; |
601 | } | |
602 | ||
603 | if (msgtype != SSL3_MT_CLIENT_HELLO) { | |
3edeb622 | 604 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); |
e3d0dae7 MC |
605 | goto end; |
606 | } | |
607 | ||
608 | /* Message sequence number can only be 0 or 1 */ | |
e8aa8b6c | 609 | if (msgseq > 2) { |
3edeb622 | 610 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER); |
e3d0dae7 MC |
611 | goto end; |
612 | } | |
613 | ||
4b1043ef MC |
614 | /* |
615 | * We don't support fragment reassembly for ClientHellos whilst | |
616 | * listening because that would require server side state (which is | |
617 | * against the whole point of the ClientHello/HelloVerifyRequest | |
618 | * mechanism). Instead we only look at the first ClientHello fragment | |
619 | * and require that the cookie must be contained within it. | |
620 | */ | |
621 | if (fragoff != 0 || fraglen > msglen) { | |
622 | /* Non initial ClientHello fragment (or bad fragment) */ | |
3edeb622 | 623 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO); |
e3d0dae7 MC |
624 | goto end; |
625 | } | |
626 | ||
627 | if (s->msg_callback) | |
628 | s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data, | |
4b1043ef | 629 | fraglen + DTLS1_HM_HEADER_LENGTH, s, |
e3d0dae7 MC |
630 | s->msg_callback_arg); |
631 | ||
632 | if (!PACKET_get_net_2(&msgpayload, &clientvers)) { | |
3edeb622 | 633 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
e3d0dae7 MC |
634 | goto end; |
635 | } | |
636 | ||
637 | /* | |
638 | * Verify client version is supported | |
639 | */ | |
4fa52141 VD |
640 | if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) && |
641 | s->method->version != DTLS_ANY_VERSION) { | |
3edeb622 | 642 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER); |
e3d0dae7 MC |
643 | goto end; |
644 | } | |
645 | ||
646 | if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE) | |
647 | || !PACKET_get_length_prefixed_1(&msgpayload, &session) | |
648 | || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) { | |
4b1043ef MC |
649 | /* |
650 | * Could be malformed or the cookie does not fit within the initial | |
651 | * ClientHello fragment. Either way we can't handle it. | |
652 | */ | |
3edeb622 | 653 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); |
e3d0dae7 MC |
654 | goto end; |
655 | } | |
656 | ||
657 | /* | |
658 | * Check if we have a cookie or not. If not we need to send a | |
659 | * HelloVerifyRequest. | |
660 | */ | |
661 | if (PACKET_remaining(&cookiepkt) == 0) { | |
662 | next = LISTEN_SEND_VERIFY_REQUEST; | |
663 | } else { | |
664 | /* | |
665 | * We have a cookie, so lets check it. | |
666 | */ | |
667 | if (s->ctx->app_verify_cookie_cb == NULL) { | |
3edeb622 | 668 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK); |
e3d0dae7 MC |
669 | /* This is fatal */ |
670 | return -1; | |
671 | } | |
31011544 | 672 | if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt), |
8b0e934a | 673 | (unsigned int)PACKET_remaining(&cookiepkt)) == 0) { |
e3d0dae7 MC |
674 | /* |
675 | * We treat invalid cookies in the same was as no cookie as | |
676 | * per RFC6347 | |
677 | */ | |
678 | next = LISTEN_SEND_VERIFY_REQUEST; | |
679 | } else { | |
680 | /* Cookie verification succeeded */ | |
681 | next = LISTEN_SUCCESS; | |
682 | } | |
683 | } | |
684 | ||
685 | if (next == LISTEN_SEND_VERIFY_REQUEST) { | |
c536b6be MC |
686 | WPACKET wpkt; |
687 | unsigned int version; | |
688 | size_t wreclen; | |
689 | ||
e3d0dae7 MC |
690 | /* |
691 | * There was no cookie in the ClientHello so we need to send a | |
692 | * HelloVerifyRequest. If this fails we do not worry about trying | |
693 | * to resend, we just drop it. | |
694 | */ | |
695 | ||
e3d0dae7 MC |
696 | /* Generate the cookie */ |
697 | if (s->ctx->app_gen_cookie_cb == NULL || | |
373dc6e1 MC |
698 | s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 || |
699 | cookielen > 255) { | |
3edeb622 | 700 | SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE); |
e3d0dae7 MC |
701 | /* This is fatal */ |
702 | return -1; | |
703 | } | |
704 | ||
e3d0dae7 MC |
705 | /* |
706 | * Special case: for hello verify request, client version 1.0 and we | |
707 | * haven't decided which version to use yet send back using version | |
708 | * 1.0 header: otherwise some clients will ignore it. | |
709 | */ | |
c536b6be MC |
710 | version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION |
711 | : s->version; | |
712 | ||
713 | /* Construct the record and message headers */ | |
2fc4c77c MC |
714 | if (!WPACKET_init_static_len(&wpkt, |
715 | wbuf, | |
079ef6bd | 716 | ssl_get_max_send_fragment(s) |
2fc4c77c MC |
717 | + DTLS1_RT_HEADER_LENGTH, |
718 | 0) | |
c536b6be MC |
719 | || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE) |
720 | || !WPACKET_put_bytes_u16(&wpkt, version) | |
721 | /* | |
722 | * Record sequence number is always the same as in the | |
723 | * received ClientHello | |
724 | */ | |
725 | || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE) | |
726 | /* End of record, start sub packet for message */ | |
727 | || !WPACKET_start_sub_packet_u16(&wpkt) | |
728 | /* Message type */ | |
729 | || !WPACKET_put_bytes_u8(&wpkt, | |
730 | DTLS1_MT_HELLO_VERIFY_REQUEST) | |
731 | /* | |
732 | * Message length - doesn't follow normal TLS convention: | |
733 | * the length isn't the last thing in the message header. | |
734 | * We'll need to fill this in later when we know the | |
735 | * length. Set it to zero for now | |
736 | */ | |
737 | || !WPACKET_put_bytes_u24(&wpkt, 0) | |
738 | /* | |
739 | * Message sequence number is always 0 for a | |
740 | * HelloVerifyRequest | |
741 | */ | |
742 | || !WPACKET_put_bytes_u16(&wpkt, 0) | |
743 | /* | |
744 | * We never fragment a HelloVerifyRequest, so fragment | |
745 | * offset is 0 | |
746 | */ | |
747 | || !WPACKET_put_bytes_u24(&wpkt, 0) | |
748 | /* | |
749 | * Fragment length is the same as message length, but | |
750 | * this *is* the last thing in the message header so we | |
751 | * can just start a sub-packet. No need to come back | |
752 | * later for this one. | |
753 | */ | |
754 | || !WPACKET_start_sub_packet_u24(&wpkt) | |
755 | /* Create the actual HelloVerifyRequest body */ | |
756 | || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen) | |
757 | /* Close message body */ | |
758 | || !WPACKET_close(&wpkt) | |
759 | /* Close record body */ | |
760 | || !WPACKET_close(&wpkt) | |
761 | || !WPACKET_get_total_written(&wpkt, &wreclen) | |
762 | || !WPACKET_finish(&wpkt)) { | |
763 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); | |
764 | WPACKET_cleanup(&wpkt); | |
765 | /* This is fatal */ | |
766 | return -1; | |
e3d0dae7 MC |
767 | } |
768 | ||
769 | /* | |
c536b6be MC |
770 | * Fix up the message len in the message header. Its the same as the |
771 | * fragment len which has been filled in by WPACKET, so just copy | |
772 | * that. Destination for the message len is after the record header | |
773 | * plus one byte for the message content type. The source is the | |
774 | * last 3 bytes of the message header | |
e3d0dae7 | 775 | */ |
2fc4c77c MC |
776 | memcpy(&wbuf[DTLS1_RT_HEADER_LENGTH + 1], |
777 | &wbuf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3], | |
c536b6be | 778 | 3); |
e3d0dae7 MC |
779 | |
780 | if (s->msg_callback) | |
781 | s->msg_callback(1, 0, SSL3_RT_HEADER, buf, | |
782 | DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); | |
783 | ||
ce0865d8 MC |
784 | if ((tmpclient = BIO_ADDR_new()) == NULL) { |
785 | SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE); | |
786 | goto end; | |
787 | } | |
788 | ||
e3d0dae7 | 789 | /* |
8483a003 | 790 | * This is unnecessary if rbio and wbio are one and the same - but |
ce0865d8 MC |
791 | * maybe they're not. We ignore errors here - some BIOs do not |
792 | * support this. | |
e3d0dae7 | 793 | */ |
e8aa8b6c | 794 | if (BIO_dgram_get_peer(rbio, tmpclient) > 0) { |
ce0865d8 | 795 | (void)BIO_dgram_set_peer(wbio, tmpclient); |
e3d0dae7 | 796 | } |
d858c876 RL |
797 | BIO_ADDR_free(tmpclient); |
798 | tmpclient = NULL; | |
e3d0dae7 | 799 | |
8b0e934a | 800 | /* TODO(size_t): convert this call */ |
2fc4c77c | 801 | if (BIO_write(wbio, wbuf, wreclen) < (int)wreclen) { |
e8aa8b6c | 802 | if (BIO_should_retry(wbio)) { |
e3d0dae7 MC |
803 | /* |
804 | * Non-blocking IO...but we're stateless, so we're just | |
805 | * going to drop this packet. | |
806 | */ | |
807 | goto end; | |
808 | } | |
809 | return -1; | |
810 | } | |
811 | ||
812 | if (BIO_flush(wbio) <= 0) { | |
e8aa8b6c | 813 | if (BIO_should_retry(wbio)) { |
e3d0dae7 MC |
814 | /* |
815 | * Non-blocking IO...but we're stateless, so we're just | |
816 | * going to drop this packet. | |
817 | */ | |
818 | goto end; | |
819 | } | |
820 | return -1; | |
821 | } | |
822 | } | |
823 | } while (next != LISTEN_SUCCESS); | |
824 | ||
825 | /* | |
826 | * Set expected sequence numbers to continue the handshake. | |
827 | */ | |
828 | s->d1->handshake_read_seq = 1; | |
829 | s->d1->handshake_write_seq = 1; | |
830 | s->d1->next_handshake_write_seq = 1; | |
831 | DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq); | |
832 | ||
833 | /* | |
834 | * We are doing cookie exchange, so make sure we set that option in the | |
835 | * SSL object | |
836 | */ | |
0f113f3e | 837 | SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); |
1fc3ac80 | 838 | |
31fd10e6 MC |
839 | /* |
840 | * Tell the state machine that we've done the initial hello verify | |
841 | * exchange | |
842 | */ | |
843 | ossl_statem_set_hello_verify_done(s); | |
e3d0dae7 | 844 | |
a230b26e EK |
845 | /* |
846 | * Some BIOs may not support this. If we fail we clear the client address | |
847 | */ | |
ce0865d8 MC |
848 | if (BIO_dgram_get_peer(rbio, client) <= 0) |
849 | BIO_ADDR_clear(client); | |
1fc3ac80 | 850 | |
079ef6bd MC |
851 | /* Buffer the record in the processed_rcds queue */ |
852 | if (!dtls_buffer_listen_record(s, reclen, seq, align)) | |
853 | return -1; | |
2fc4c77c | 854 | |
e3d0dae7 | 855 | ret = 1; |
a230b26e | 856 | end: |
d858c876 | 857 | BIO_ADDR_free(tmpclient); |
e3d0dae7 | 858 | return ret; |
0f113f3e | 859 | } |
f9e55034 | 860 | #endif |
173e72e6 | 861 | |
173e72e6 | 862 | static int dtls1_handshake_write(SSL *s) |
0f113f3e MC |
863 | { |
864 | return dtls1_do_write(s, SSL3_RT_HANDSHAKE); | |
865 | } | |
8ba708e5 | 866 | |
8ba708e5 MC |
867 | int dtls1_shutdown(SSL *s) |
868 | { | |
869 | int ret; | |
870 | #ifndef OPENSSL_NO_SCTP | |
871 | BIO *wbio; | |
872 | ||
873 | wbio = SSL_get_wbio(s); | |
874 | if (wbio != NULL && BIO_dgram_is_sctp(wbio) && | |
875 | !(s->shutdown & SSL_SENT_SHUTDOWN)) { | |
876 | ret = BIO_dgram_sctp_wait_for_dry(wbio); | |
877 | if (ret < 0) | |
878 | return -1; | |
879 | ||
880 | if (ret == 0) | |
881 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, | |
882 | NULL); | |
883 | } | |
884 | #endif | |
885 | ret = ssl3_shutdown(s); | |
886 | #ifndef OPENSSL_NO_SCTP | |
887 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL); | |
888 | #endif | |
889 | return ret; | |
890 | } | |
891 | ||
892 | int dtls1_query_mtu(SSL *s) | |
893 | { | |
894 | if (s->d1->link_mtu) { | |
895 | s->d1->mtu = | |
896 | s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); | |
897 | s->d1->link_mtu = 0; | |
898 | } | |
899 | ||
900 | /* AHA! Figure out the MTU, and stick to the right size */ | |
901 | if (s->d1->mtu < dtls1_min_mtu(s)) { | |
902 | if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { | |
903 | s->d1->mtu = | |
904 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); | |
905 | ||
906 | /* | |
907 | * I've seen the kernel return bogus numbers when it doesn't know | |
908 | * (initial write), so just make sure we have a reasonable number | |
909 | */ | |
910 | if (s->d1->mtu < dtls1_min_mtu(s)) { | |
911 | /* Set to min mtu */ | |
912 | s->d1->mtu = dtls1_min_mtu(s); | |
913 | BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, | |
8b0e934a | 914 | (long)s->d1->mtu, NULL); |
8ba708e5 MC |
915 | } |
916 | } else | |
917 | return 0; | |
918 | } | |
919 | return 1; | |
920 | } | |
921 | ||
7ee8627f | 922 | static size_t dtls1_link_min_mtu(void) |
8ba708e5 MC |
923 | { |
924 | return (g_probable_mtu[(sizeof(g_probable_mtu) / | |
925 | sizeof(g_probable_mtu[0])) - 1]); | |
926 | } | |
927 | ||
7ee8627f | 928 | size_t dtls1_min_mtu(SSL *s) |
8ba708e5 MC |
929 | { |
930 | return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); | |
931 | } | |
045bd047 DW |
932 | |
933 | size_t DTLS_get_data_mtu(const SSL *s) | |
934 | { | |
935 | size_t mac_overhead, int_overhead, blocksize, ext_overhead; | |
936 | const SSL_CIPHER *ciph = SSL_get_current_cipher(s); | |
937 | size_t mtu = s->d1->mtu; | |
938 | ||
939 | if (ciph == NULL) | |
940 | return 0; | |
941 | ||
942 | if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead, | |
943 | &blocksize, &ext_overhead)) | |
944 | return 0; | |
945 | ||
28a31a0a | 946 | if (SSL_READ_ETM(s)) |
045bd047 DW |
947 | ext_overhead += mac_overhead; |
948 | else | |
949 | int_overhead += mac_overhead; | |
950 | ||
951 | /* Subtract external overhead (e.g. IV/nonce, separate MAC) */ | |
952 | if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu) | |
953 | return 0; | |
954 | mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH; | |
955 | ||
956 | /* Round encrypted payload down to cipher block size (for CBC etc.) | |
957 | * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */ | |
958 | if (blocksize) | |
959 | mtu -= (mtu % blocksize); | |
960 | ||
961 | /* Subtract internal overhead (e.g. CBC padding len byte) */ | |
962 | if (int_overhead >= mtu) | |
963 | return 0; | |
964 | mtu -= int_overhead; | |
965 | ||
966 | return mtu; | |
967 | } | |
fa4b82cc AH |
968 | |
969 | void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb) | |
970 | { | |
971 | s->d1->timer_cb = cb; | |
972 | } |