1/*
2 * DTLS implementation written by Nagendra Modadugu
3 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
4 */
5/* ====================================================================
6 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@openssl.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
59 * All rights reserved.
60 *
61 * This package is an SSL implementation written
62 * by Eric Young (eay@cryptsoft.com).
63 * The implementation was written so as to conform with Netscapes SSL.
64 *
65 * This library is free for commercial and non-commercial use as long as
66 * the following conditions are aheared to. The following conditions
67 * apply to all code found in this distribution, be it the RC4, RSA,
68 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
69 * included with this distribution is covered by the same copyright terms
70 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
71 *
72 * Copyright remains Eric Young's, and as such any Copyright notices in
73 * the code are not to be removed.
74 * If this package is used in a product, Eric Young should be given attribution
75 * as the author of the parts of the library used.
76 * This can be in the form of a textual message at program startup or
77 * in documentation (online or textual) provided with the package.
78 *
79 * Redistribution and use in source and binary forms, with or without
80 * modification, are permitted provided that the following conditions
81 * are met:
82 * 1. Redistributions of source code must retain the copyright
83 * notice, this list of conditions and the following disclaimer.
84 * 2. Redistributions in binary form must reproduce the above copyright
85 * notice, this list of conditions and the following disclaimer in the
86 * documentation and/or other materials provided with the distribution.
87 * 3. All advertising materials mentioning features or use of this software
88 * must display the following acknowledgement:
89 * "This product includes cryptographic software written by
90 * Eric Young (eay@cryptsoft.com)"
91 * The word 'cryptographic' can be left out if the rouines from the library
92 * being used are not cryptographic related :-).
93 * 4. If you include any Windows specific code (or a derivative thereof) from
94 * the apps directory (application code) you must include an acknowledgement:
95 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
96 *
97 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
98 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
99 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
100 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
101 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
102 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
103 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
104 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
105 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
106 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
107 * SUCH DAMAGE.
108 *
109 * The licence and distribution terms for any publically available version or
110 * derivative of this code cannot be changed. i.e. this code cannot simply be
111 * copied and put under another distribution licence
112 * [including the GNU Public Licence.] */
113
114#include <openssl/ssl.h>
115
116#include <assert.h>
117#include <limits.h>
118#include <string.h>
119
120#include <openssl/err.h>
121#include <openssl/evp.h>
122#include <openssl/mem.h>
123#include <openssl/rand.h>
124
125#include "../crypto/internal.h"
126#include "internal.h"
127
128
129BSSL_NAMESPACE_BEGIN
130
131// TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable
132// for these values? Notably, why is kMinMTU a function of the transport
133// protocol's overhead rather than, say, what's needed to hold a minimally-sized
134// handshake fragment plus protocol overhead.
135
136// kMinMTU is the minimum acceptable MTU value.
137static const unsigned int kMinMTU = 256 - 28;
138
139// kDefaultMTU is the default MTU value to use if neither the user nor
140// the underlying BIO supplies one.
141static const unsigned int kDefaultMTU = 1500 - 28;
142
143
144// Receiving handshake messages.
145
146hm_fragment::~hm_fragment() {
147 OPENSSL_free(ptr: data);
148 OPENSSL_free(ptr: reassembly);
149}
150
151static UniquePtr<hm_fragment> dtls1_hm_fragment_new(
152 const struct hm_header_st *msg_hdr) {
153 ScopedCBB cbb;
154 UniquePtr<hm_fragment> frag = MakeUnique<hm_fragment>();
155 if (!frag) {
156 return nullptr;
157 }
158 frag->type = msg_hdr->type;
159 frag->seq = msg_hdr->seq;
160 frag->msg_len = msg_hdr->msg_len;
161
162 // Allocate space for the reassembled message and fill in the header.
163 frag->data =
164 (uint8_t *)OPENSSL_malloc(DTLS1_HM_HEADER_LENGTH + msg_hdr->msg_len);
165 if (frag->data == NULL) {
166 return nullptr;
167 }
168
169 if (!CBB_init_fixed(cbb: cbb.get(), buf: frag->data, DTLS1_HM_HEADER_LENGTH) ||
170 !CBB_add_u8(cbb: cbb.get(), value: msg_hdr->type) ||
171 !CBB_add_u24(cbb: cbb.get(), value: msg_hdr->msg_len) ||
172 !CBB_add_u16(cbb: cbb.get(), value: msg_hdr->seq) ||
173 !CBB_add_u24(cbb: cbb.get(), value: 0 /* frag_off */) ||
174 !CBB_add_u24(cbb: cbb.get(), value: msg_hdr->msg_len) ||
175 !CBB_finish(cbb: cbb.get(), NULL, NULL)) {
176 return nullptr;
177 }
178
179 // If the handshake message is empty, |frag->reassembly| is NULL.
180 if (msg_hdr->msg_len > 0) {
181 // Initialize reassembly bitmask.
182 if (msg_hdr->msg_len + 7 < msg_hdr->msg_len) {
183 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
184 return nullptr;
185 }
186 size_t bitmask_len = (msg_hdr->msg_len + 7) / 8;
187 frag->reassembly = (uint8_t *)OPENSSL_malloc(size: bitmask_len);
188 if (frag->reassembly == NULL) {
189 return nullptr;
190 }
191 OPENSSL_memset(dst: frag->reassembly, c: 0, n: bitmask_len);
192 }
193
194 return frag;
195}
196
197// bit_range returns a |uint8_t| with bits |start|, inclusive, to |end|,
198// exclusive, set.
199static uint8_t bit_range(size_t start, size_t end) {
200 return (uint8_t)(~((1u << start) - 1) & ((1u << end) - 1));
201}
202
203// dtls1_hm_fragment_mark marks bytes |start|, inclusive, to |end|, exclusive,
204// as received in |frag|. If |frag| becomes complete, it clears
205// |frag->reassembly|. The range must be within the bounds of |frag|'s message
206// and |frag->reassembly| must not be NULL.
207static void dtls1_hm_fragment_mark(hm_fragment *frag, size_t start,
208 size_t end) {
209 size_t msg_len = frag->msg_len;
210
211 if (frag->reassembly == NULL || start > end || end > msg_len) {
212 assert(0);
213 return;
214 }
215 // A zero-length message will never have a pending reassembly.
216 assert(msg_len > 0);
217
218 if (start == end) {
219 return;
220 }
221
222 if ((start >> 3) == (end >> 3)) {
223 frag->reassembly[start >> 3] |= bit_range(start: start & 7, end: end & 7);
224 } else {
225 frag->reassembly[start >> 3] |= bit_range(start: start & 7, end: 8);
226 for (size_t i = (start >> 3) + 1; i < (end >> 3); i++) {
227 frag->reassembly[i] = 0xff;
228 }
229 if ((end & 7) != 0) {
230 frag->reassembly[end >> 3] |= bit_range(start: 0, end: end & 7);
231 }
232 }
233
234 // Check if the fragment is complete.
235 for (size_t i = 0; i < (msg_len >> 3); i++) {
236 if (frag->reassembly[i] != 0xff) {
237 return;
238 }
239 }
240 if ((msg_len & 7) != 0 &&
241 frag->reassembly[msg_len >> 3] != bit_range(start: 0, end: msg_len & 7)) {
242 return;
243 }
244
245 OPENSSL_free(ptr: frag->reassembly);
246 frag->reassembly = NULL;
247}
248
249// dtls1_is_current_message_complete returns whether the current handshake
250// message is complete.
251static bool dtls1_is_current_message_complete(const SSL *ssl) {
252 size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
253 hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
254 return frag != NULL && frag->reassembly == NULL;
255}
256
257// dtls1_get_incoming_message returns the incoming message corresponding to
258// |msg_hdr|. If none exists, it creates a new one and inserts it in the
259// queue. Otherwise, it checks |msg_hdr| is consistent with the existing one. It
260// returns NULL on failure. The caller does not take ownership of the result.
261static hm_fragment *dtls1_get_incoming_message(
262 SSL *ssl, uint8_t *out_alert, const struct hm_header_st *msg_hdr) {
263 if (msg_hdr->seq < ssl->d1->handshake_read_seq ||
264 msg_hdr->seq - ssl->d1->handshake_read_seq >= SSL_MAX_HANDSHAKE_FLIGHT) {
265 *out_alert = SSL_AD_INTERNAL_ERROR;
266 return NULL;
267 }
268
269 size_t idx = msg_hdr->seq % SSL_MAX_HANDSHAKE_FLIGHT;
270 hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
271 if (frag != NULL) {
272 assert(frag->seq == msg_hdr->seq);
273 // The new fragment must be compatible with the previous fragments from this
274 // message.
275 if (frag->type != msg_hdr->type ||
276 frag->msg_len != msg_hdr->msg_len) {
277 OPENSSL_PUT_ERROR(SSL, SSL_R_FRAGMENT_MISMATCH);
278 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
279 return NULL;
280 }
281 return frag;
282 }
283
284 // This is the first fragment from this message.
285 ssl->d1->incoming_messages[idx] = dtls1_hm_fragment_new(msg_hdr);
286 if (!ssl->d1->incoming_messages[idx]) {
287 *out_alert = SSL_AD_INTERNAL_ERROR;
288 return NULL;
289 }
290 return ssl->d1->incoming_messages[idx].get();
291}
292
293ssl_open_record_t dtls1_open_handshake(SSL *ssl, size_t *out_consumed,
294 uint8_t *out_alert, Span<uint8_t> in) {
295 uint8_t type;
296 Span<uint8_t> record;
297 auto ret = dtls_open_record(ssl, out_type: &type, out: &record, out_consumed, out_alert, in);
298 if (ret != ssl_open_record_success) {
299 return ret;
300 }
301
302 switch (type) {
303 case SSL3_RT_APPLICATION_DATA:
304 // Unencrypted application data records are always illegal.
305 if (ssl->s3->aead_read_ctx->is_null_cipher()) {
306 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
307 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
308 return ssl_open_record_error;
309 }
310
311 // Out-of-order application data may be received between ChangeCipherSpec
312 // and finished. Discard it.
313 return ssl_open_record_discard;
314
315 case SSL3_RT_CHANGE_CIPHER_SPEC:
316 // We do not support renegotiation, so encrypted ChangeCipherSpec records
317 // are illegal.
318 if (!ssl->s3->aead_read_ctx->is_null_cipher()) {
319 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
320 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
321 return ssl_open_record_error;
322 }
323
324 if (record.size() != 1u || record[0] != SSL3_MT_CCS) {
325 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_CHANGE_CIPHER_SPEC);
326 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
327 return ssl_open_record_error;
328 }
329
330 // Flag the ChangeCipherSpec for later.
331 ssl->d1->has_change_cipher_spec = true;
332 ssl_do_msg_callback(ssl, is_write: 0 /* read */, SSL3_RT_CHANGE_CIPHER_SPEC,
333 in: record);
334 return ssl_open_record_success;
335
336 case SSL3_RT_HANDSHAKE:
337 // Break out to main processing.
338 break;
339
340 default:
341 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
342 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
343 return ssl_open_record_error;
344 }
345
346 CBS cbs;
347 CBS_init(cbs: &cbs, data: record.data(), len: record.size());
348 while (CBS_len(cbs: &cbs) > 0) {
349 // Read a handshake fragment.
350 struct hm_header_st msg_hdr;
351 CBS body;
352 if (!dtls1_parse_fragment(cbs: &cbs, out_hdr: &msg_hdr, out_body: &body)) {
353 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HANDSHAKE_RECORD);
354 *out_alert = SSL_AD_DECODE_ERROR;
355 return ssl_open_record_error;
356 }
357
358 const size_t frag_off = msg_hdr.frag_off;
359 const size_t frag_len = msg_hdr.frag_len;
360 const size_t msg_len = msg_hdr.msg_len;
361 if (frag_off > msg_len || frag_off + frag_len < frag_off ||
362 frag_off + frag_len > msg_len ||
363 msg_len > ssl_max_handshake_message_len(ssl)) {
364 OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
365 *out_alert = SSL_AD_ILLEGAL_PARAMETER;
366 return ssl_open_record_error;
367 }
368
369 // The encrypted epoch in DTLS has only one handshake message.
370 if (ssl->d1->r_epoch == 1 && msg_hdr.seq != ssl->d1->handshake_read_seq) {
371 OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
372 *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
373 return ssl_open_record_error;
374 }
375
376 if (msg_hdr.seq < ssl->d1->handshake_read_seq ||
377 msg_hdr.seq >
378 (unsigned)ssl->d1->handshake_read_seq + SSL_MAX_HANDSHAKE_FLIGHT) {
379 // Ignore fragments from the past, or ones too far in the future.
380 continue;
381 }
382
383 hm_fragment *frag = dtls1_get_incoming_message(ssl, out_alert, msg_hdr: &msg_hdr);
384 if (frag == NULL) {
385 return ssl_open_record_error;
386 }
387 assert(frag->msg_len == msg_len);
388
389 if (frag->reassembly == NULL) {
390 // The message is already assembled.
391 continue;
392 }
393 assert(msg_len > 0);
394
395 // Copy the body into the fragment.
396 OPENSSL_memcpy(dst: frag->data + DTLS1_HM_HEADER_LENGTH + frag_off,
397 src: CBS_data(cbs: &body), n: CBS_len(cbs: &body));
398 dtls1_hm_fragment_mark(frag, start: frag_off, end: frag_off + frag_len);
399 }
400
401 return ssl_open_record_success;
402}
403
404bool dtls1_get_message(const SSL *ssl, SSLMessage *out) {
405 if (!dtls1_is_current_message_complete(ssl)) {
406 return false;
407 }
408
409 size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
410 hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
411 out->type = frag->type;
412 CBS_init(cbs: &out->body, data: frag->data + DTLS1_HM_HEADER_LENGTH, len: frag->msg_len);
413 CBS_init(cbs: &out->raw, data: frag->data, DTLS1_HM_HEADER_LENGTH + frag->msg_len);
414 out->is_v2_hello = false;
415 if (!ssl->s3->has_message) {
416 ssl_do_msg_callback(ssl, is_write: 0 /* read */, SSL3_RT_HANDSHAKE, in: out->raw);
417 ssl->s3->has_message = true;
418 }
419 return true;
420}
421
422void dtls1_next_message(SSL *ssl) {
423 assert(ssl->s3->has_message);
424 assert(dtls1_is_current_message_complete(ssl));
425 size_t index = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
426 ssl->d1->incoming_messages[index].reset();
427 ssl->d1->handshake_read_seq++;
428 ssl->s3->has_message = false;
429 // If we previously sent a flight, mark it as having a reply, so
430 // |on_handshake_complete| can manage post-handshake retransmission.
431 if (ssl->d1->outgoing_messages_complete) {
432 ssl->d1->flight_has_reply = true;
433 }
434}
435
436bool dtls_has_unprocessed_handshake_data(const SSL *ssl) {
437 size_t current = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
438 for (size_t i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) {
439 // Skip the current message.
440 if (ssl->s3->has_message && i == current) {
441 assert(dtls1_is_current_message_complete(ssl));
442 continue;
443 }
444 if (ssl->d1->incoming_messages[i] != nullptr) {
445 return true;
446 }
447 }
448 return false;
449}
450
451bool dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr,
452 CBS *out_body) {
453 OPENSSL_memset(dst: out_hdr, c: 0x00, n: sizeof(struct hm_header_st));
454
455 if (!CBS_get_u8(cbs, out: &out_hdr->type) ||
456 !CBS_get_u24(cbs, out: &out_hdr->msg_len) ||
457 !CBS_get_u16(cbs, out: &out_hdr->seq) ||
458 !CBS_get_u24(cbs, out: &out_hdr->frag_off) ||
459 !CBS_get_u24(cbs, out: &out_hdr->frag_len) ||
460 !CBS_get_bytes(cbs, out: out_body, len: out_hdr->frag_len)) {
461 return false;
462 }
463
464 return true;
465}
466
467ssl_open_record_t dtls1_open_change_cipher_spec(SSL *ssl, size_t *out_consumed,
468 uint8_t *out_alert,
469 Span<uint8_t> in) {
470 if (!ssl->d1->has_change_cipher_spec) {
471 // dtls1_open_handshake processes both handshake and ChangeCipherSpec.
472 auto ret = dtls1_open_handshake(ssl, out_consumed, out_alert, in);
473 if (ret != ssl_open_record_success) {
474 return ret;
475 }
476 }
477 if (ssl->d1->has_change_cipher_spec) {
478 ssl->d1->has_change_cipher_spec = false;
479 return ssl_open_record_success;
480 }
481 return ssl_open_record_discard;
482}
483
484
485// Sending handshake messages.
486
487void DTLS_OUTGOING_MESSAGE::Clear() { data.Reset(); }
488
489void dtls_clear_outgoing_messages(SSL *ssl) {
490 for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) {
491 ssl->d1->outgoing_messages[i].Clear();
492 }
493 ssl->d1->outgoing_messages_len = 0;
494 ssl->d1->outgoing_written = 0;
495 ssl->d1->outgoing_offset = 0;
496 ssl->d1->outgoing_messages_complete = false;
497 ssl->d1->flight_has_reply = false;
498}
499
500bool dtls1_init_message(const SSL *ssl, CBB *cbb, CBB *body, uint8_t type) {
501 // Pick a modest size hint to save most of the |realloc| calls.
502 if (!CBB_init(cbb, initial_capacity: 64) ||
503 !CBB_add_u8(cbb, value: type) ||
504 !CBB_add_u24(cbb, value: 0 /* length (filled in later) */) ||
505 !CBB_add_u16(cbb, value: ssl->d1->handshake_write_seq) ||
506 !CBB_add_u24(cbb, value: 0 /* offset */) ||
507 !CBB_add_u24_length_prefixed(cbb, out_contents: body)) {
508 return false;
509 }
510
511 return true;
512}
513
514bool dtls1_finish_message(const SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg) {
515 if (!CBBFinishArray(cbb, out: out_msg) ||
516 out_msg->size() < DTLS1_HM_HEADER_LENGTH) {
517 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
518 return false;
519 }
520
521 // Fix up the header. Copy the fragment length into the total message
522 // length.
523 OPENSSL_memcpy(dst: out_msg->data() + 1,
524 src: out_msg->data() + DTLS1_HM_HEADER_LENGTH - 3, n: 3);
525 return true;
526}
527
528// ssl_size_t_greater_than_32_bits returns whether |v| exceeds the bounds of a
529// 32-bit value. The obvious thing doesn't work because, in some 32-bit build
530// configurations, the compiler warns that the test is always false and breaks
531// the build.
532static bool ssl_size_t_greater_than_32_bits(size_t v) {
533#if defined(OPENSSL_64_BIT)
534 return v > 0xffffffff;
535#elif defined(OPENSSL_32_BIT)
536 return false;
537#else
538#error "Building for neither 32- nor 64-bits."
539#endif
540}
541
542// add_outgoing adds a new handshake message or ChangeCipherSpec to the current
543// outgoing flight. It returns true on success and false on error.
544static bool add_outgoing(SSL *ssl, bool is_ccs, Array<uint8_t> data) {
545 if (ssl->d1->outgoing_messages_complete) {
546 // If we've begun writing a new flight, we received the peer flight. Discard
547 // the timer and the our flight.
548 dtls1_stop_timer(ssl);
549 dtls_clear_outgoing_messages(ssl);
550 }
551
552 static_assert(SSL_MAX_HANDSHAKE_FLIGHT <
553 (1 << 8 * sizeof(ssl->d1->outgoing_messages_len)),
554 "outgoing_messages_len is too small");
555 if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT ||
556 ssl_size_t_greater_than_32_bits(v: data.size())) {
557 assert(false);
558 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
559 return false;
560 }
561
562 if (!is_ccs) {
563 // TODO(svaldez): Move this up a layer to fix abstraction for SSLTranscript
564 // on hs.
565 if (ssl->s3->hs != NULL &&
566 !ssl->s3->hs->transcript.Update(in: data)) {
567 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
568 return false;
569 }
570 ssl->d1->handshake_write_seq++;
571 }
572
573 DTLS_OUTGOING_MESSAGE *msg =
574 &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len];
575 msg->data = std::move(data);
576 msg->epoch = ssl->d1->w_epoch;
577 msg->is_ccs = is_ccs;
578
579 ssl->d1->outgoing_messages_len++;
580 return true;
581}
582
583bool dtls1_add_message(SSL *ssl, Array<uint8_t> data) {
584 return add_outgoing(ssl, is_ccs: false /* handshake */, data: std::move(data));
585}
586
587bool dtls1_add_change_cipher_spec(SSL *ssl) {
588 return add_outgoing(ssl, is_ccs: true /* ChangeCipherSpec */, data: Array<uint8_t>());
589}
590
591// dtls1_update_mtu updates the current MTU from the BIO, ensuring it is above
592// the minimum.
593static void dtls1_update_mtu(SSL *ssl) {
594 // TODO(davidben): No consumer implements |BIO_CTRL_DGRAM_SET_MTU| and the
595 // only |BIO_CTRL_DGRAM_QUERY_MTU| implementation could use
596 // |SSL_set_mtu|. Does this need to be so complex?
597 if (ssl->d1->mtu < dtls1_min_mtu() &&
598 !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
599 long mtu = BIO_ctrl(bio: ssl->wbio.get(), BIO_CTRL_DGRAM_QUERY_MTU, larg: 0, NULL);
600 if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
601 ssl->d1->mtu = (unsigned)mtu;
602 } else {
603 ssl->d1->mtu = kDefaultMTU;
604 BIO_ctrl(bio: ssl->wbio.get(), BIO_CTRL_DGRAM_SET_MTU, larg: ssl->d1->mtu, NULL);
605 }
606 }
607
608 // The MTU should be above the minimum now.
609 assert(ssl->d1->mtu >= dtls1_min_mtu());
610}
611
612enum seal_result_t {
613 seal_error,
614 seal_no_progress,
615 seal_partial,
616 seal_success,
617};
618
619// seal_next_message seals |msg|, which must be the next message, to |out|. If
620// progress was made, it returns |seal_partial| or |seal_success| and sets
621// |*out_len| to the number of bytes written.
622static enum seal_result_t seal_next_message(SSL *ssl, uint8_t *out,
623 size_t *out_len, size_t max_out,
624 const DTLS_OUTGOING_MESSAGE *msg) {
625 assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len);
626 assert(msg == &ssl->d1->outgoing_messages[ssl->d1->outgoing_written]);
627
628 enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch;
629 if (ssl->d1->w_epoch >= 1 && msg->epoch == ssl->d1->w_epoch - 1) {
630 use_epoch = dtls1_use_previous_epoch;
631 } else if (msg->epoch != ssl->d1->w_epoch) {
632 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
633 return seal_error;
634 }
635
636 size_t overhead = dtls_max_seal_overhead(ssl, use_epoch);
637 size_t prefix = dtls_seal_prefix_len(ssl, use_epoch);
638
639 if (msg->is_ccs) {
640 // Check there is room for the ChangeCipherSpec.
641 static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
642 if (max_out < sizeof(kChangeCipherSpec) + overhead) {
643 return seal_no_progress;
644 }
645
646 if (!dtls_seal_record(ssl, out, out_len, max_out,
647 SSL3_RT_CHANGE_CIPHER_SPEC, in: kChangeCipherSpec,
648 in_len: sizeof(kChangeCipherSpec), use_epoch)) {
649 return seal_error;
650 }
651
652 ssl_do_msg_callback(ssl, is_write: 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC,
653 in: kChangeCipherSpec);
654 return seal_success;
655 }
656
657 // DTLS messages are serialized as a single fragment in |msg|.
658 CBS cbs, body;
659 struct hm_header_st hdr;
660 CBS_init(cbs: &cbs, data: msg->data.data(), len: msg->data.size());
661 if (!dtls1_parse_fragment(cbs: &cbs, out_hdr: &hdr, out_body: &body) ||
662 hdr.frag_off != 0 ||
663 hdr.frag_len != CBS_len(cbs: &body) ||
664 hdr.msg_len != CBS_len(cbs: &body) ||
665 !CBS_skip(cbs: &body, len: ssl->d1->outgoing_offset) ||
666 CBS_len(cbs: &cbs) != 0) {
667 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
668 return seal_error;
669 }
670
671 // Determine how much progress can be made.
672 if (max_out < DTLS1_HM_HEADER_LENGTH + 1 + overhead || max_out < prefix) {
673 return seal_no_progress;
674 }
675 size_t todo = CBS_len(cbs: &body);
676 if (todo > max_out - DTLS1_HM_HEADER_LENGTH - overhead) {
677 todo = max_out - DTLS1_HM_HEADER_LENGTH - overhead;
678 }
679
680 // Assemble a fragment, to be sealed in-place.
681 ScopedCBB cbb;
682 CBB child;
683 uint8_t *frag = out + prefix;
684 size_t max_frag = max_out - prefix, frag_len;
685 if (!CBB_init_fixed(cbb: cbb.get(), buf: frag, len: max_frag) ||
686 !CBB_add_u8(cbb: cbb.get(), value: hdr.type) ||
687 !CBB_add_u24(cbb: cbb.get(), value: hdr.msg_len) ||
688 !CBB_add_u16(cbb: cbb.get(), value: hdr.seq) ||
689 !CBB_add_u24(cbb: cbb.get(), value: ssl->d1->outgoing_offset) ||
690 !CBB_add_u24_length_prefixed(cbb: cbb.get(), out_contents: &child) ||
691 !CBB_add_bytes(cbb: &child, data: CBS_data(cbs: &body), len: todo) ||
692 !CBB_finish(cbb: cbb.get(), NULL, out_len: &frag_len)) {
693 OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
694 return seal_error;
695 }
696
697 ssl_do_msg_callback(ssl, is_write: 1 /* write */, SSL3_RT_HANDSHAKE,
698 in: MakeSpan(ptr: frag, size: frag_len));
699
700 if (!dtls_seal_record(ssl, out, out_len, max_out, SSL3_RT_HANDSHAKE,
701 in: out + prefix, in_len: frag_len, use_epoch)) {
702 return seal_error;
703 }
704
705 if (todo == CBS_len(cbs: &body)) {
706 // The next message is complete.
707 ssl->d1->outgoing_offset = 0;
708 return seal_success;
709 }
710
711 ssl->d1->outgoing_offset += todo;
712 return seal_partial;
713}
714
715// seal_next_packet writes as much of the next flight as possible to |out| and
716// advances |ssl->d1->outgoing_written| and |ssl->d1->outgoing_offset| as
717// appropriate.
718static bool seal_next_packet(SSL *ssl, uint8_t *out, size_t *out_len,
719 size_t max_out) {
720 bool made_progress = false;
721 size_t total = 0;
722 assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len);
723 for (; ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len;
724 ssl->d1->outgoing_written++) {
725 const DTLS_OUTGOING_MESSAGE *msg =
726 &ssl->d1->outgoing_messages[ssl->d1->outgoing_written];
727 size_t len;
728 enum seal_result_t ret = seal_next_message(ssl, out, out_len: &len, max_out, msg);
729 switch (ret) {
730 case seal_error:
731 return false;
732
733 case seal_no_progress:
734 goto packet_full;
735
736 case seal_partial:
737 case seal_success:
738 out += len;
739 max_out -= len;
740 total += len;
741 made_progress = true;
742
743 if (ret == seal_partial) {
744 goto packet_full;
745 }
746 break;
747 }
748 }
749
750packet_full:
751 // The MTU was too small to make any progress.
752 if (!made_progress) {
753 OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL);
754 return false;
755 }
756
757 *out_len = total;
758 return true;
759}
760
761static int send_flight(SSL *ssl) {
762 if (ssl->s3->write_shutdown != ssl_shutdown_none) {
763 OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
764 return -1;
765 }
766
767 if (ssl->wbio == nullptr) {
768 OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET);
769 return -1;
770 }
771
772 dtls1_update_mtu(ssl);
773
774 Array<uint8_t> packet;
775 if (!packet.Init(new_size: ssl->d1->mtu)) {
776 return -1;
777 }
778
779 while (ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len) {
780 uint8_t old_written = ssl->d1->outgoing_written;
781 uint32_t old_offset = ssl->d1->outgoing_offset;
782
783 size_t packet_len;
784 if (!seal_next_packet(ssl, out: packet.data(), out_len: &packet_len, max_out: packet.size())) {
785 return -1;
786 }
787
788 int bio_ret = BIO_write(bio: ssl->wbio.get(), data: packet.data(), len: packet_len);
789 if (bio_ret <= 0) {
790 // Retry this packet the next time around.
791 ssl->d1->outgoing_written = old_written;
792 ssl->d1->outgoing_offset = old_offset;
793 ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
794 return bio_ret;
795 }
796 }
797
798 if (BIO_flush(bio: ssl->wbio.get()) <= 0) {
799 ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
800 return -1;
801 }
802
803 return 1;
804}
805
806int dtls1_flush_flight(SSL *ssl) {
807 ssl->d1->outgoing_messages_complete = true;
808 // Start the retransmission timer for the next flight (if any).
809 dtls1_start_timer(ssl);
810 return send_flight(ssl);
811}
812
813int dtls1_retransmit_outgoing_messages(SSL *ssl) {
814 // Rewind to the start of the flight and write it again.
815 //
816 // TODO(davidben): This does not allow retransmits to be resumed on
817 // non-blocking write.
818 ssl->d1->outgoing_written = 0;
819 ssl->d1->outgoing_offset = 0;
820
821 return send_flight(ssl);
822}
823
824unsigned int dtls1_min_mtu(void) {
825 return kMinMTU;
826}
827
828BSSL_NAMESPACE_END
829

source code of flutter_engine/third_party/boringssl/src/ssl/d1_both.cc