1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.]
56 */
57 /* ====================================================================
58 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
59 *
60 * Redistribution and use in source and binary forms, with or without
61 * modification, are permitted provided that the following conditions
62 * are met:
63 *
64 * 1. Redistributions of source code must retain the above copyright
65 * notice, this list of conditions and the following disclaimer.
66 *
67 * 2. Redistributions in binary form must reproduce the above copyright
68 * notice, this list of conditions and the following disclaimer in
69 * the documentation and/or other materials provided with the
70 * distribution.
71 *
72 * 3. All advertising materials mentioning features or use of this
73 * software must display the following acknowledgment:
74 * "This product includes software developed by the OpenSSL Project
75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76 *
77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78 * endorse or promote products derived from this software without
79 * prior written permission. For written permission, please contact
80 * openssl-core@openssl.org.
81 *
82 * 5. Products derived from this software may not be called "OpenSSL"
83 * nor may "OpenSSL" appear in their names without prior written
84 * permission of the OpenSSL Project.
85 *
86 * 6. Redistributions of any form whatsoever must retain the following
87 * acknowledgment:
88 * "This product includes software developed by the OpenSSL Project
89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90 *
91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102 * OF THE POSSIBILITY OF SUCH DAMAGE.
103 * ====================================================================
104 *
105 * This product includes cryptographic software written by Eric Young
106 * (eay@cryptsoft.com). This product includes software written by Tim
107 * Hudson (tjh@cryptsoft.com). */
108
109 #include <assert.h>
110 #include <limits.h>
111 #include <stdio.h>
112 #include <string.h>
113
114 #include <openssl/buf.h>
115 #include <openssl/err.h>
116 #include <openssl/evp.h>
117 #include <openssl/mem.h>
118 #include <openssl/rand.h>
119
120 #include "internal.h"
121
122
123 static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len,
124 char fragment);
125 static int ssl3_get_record(SSL *s);
126
ssl3_read_n(SSL * s,int n,int extend)127 int ssl3_read_n(SSL *s, int n, int extend) {
128 /* If |extend| is 0, obtain new n-byte packet;
129 * if |extend| is 1, increase packet by another n bytes.
130 *
131 * The packet will be in the sub-array of |s->s3->rbuf.buf| specified by
132 * |s->packet| and |s->packet_length|. (If DTLS and |extend| is 0, additional
133 * bytes will be read into |rbuf|, up to the size of the buffer.)
134 *
135 * TODO(davidben): |dtls1_get_record| and |ssl3_get_record| have very
136 * different needs. Separate the two record layers. In DTLS, |BIO_read| is
137 * called at most once, and only when |extend| is 0. In TLS, the buffer never
138 * contains more than one record. */
139 int i, len, left;
140 uintptr_t align = 0;
141 uint8_t *pkt;
142 SSL3_BUFFER *rb;
143
144 if (n <= 0) {
145 return n;
146 }
147
148 rb = &s->s3->rbuf;
149 if (rb->buf == NULL && !ssl3_setup_read_buffer(s)) {
150 return -1;
151 }
152
153 left = rb->left;
154
155 align = (uintptr_t)rb->buf + SSL3_RT_HEADER_LENGTH;
156 align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1);
157
158 if (!extend) {
159 /* start with empty packet ... */
160 if (left == 0) {
161 rb->offset = align;
162 } else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) {
163 /* check if next packet length is large enough to justify payload
164 * alignment... */
165 pkt = rb->buf + rb->offset;
166 if (pkt[0] == SSL3_RT_APPLICATION_DATA && (pkt[3] << 8 | pkt[4]) >= 128) {
167 /* Note that even if packet is corrupted and its length field is
168 * insane, we can only be led to wrong decision about whether memmove
169 * will occur or not. Header values has no effect on memmove arguments
170 * and therefore no buffer overrun can be triggered. */
171 memmove(rb->buf + align, pkt, left);
172 rb->offset = align;
173 }
174 }
175 s->packet = rb->buf + rb->offset;
176 s->packet_length = 0;
177 /* ... now we can act as if 'extend' was set */
178 }
179
180 /* In DTLS, if there is leftover data from the previous packet or |extend| is
181 * true, clamp to the previous read. DTLS records may not span packet
182 * boundaries. */
183 if (SSL_IS_DTLS(s) && n > left && (left > 0 || extend)) {
184 n = left;
185 }
186
187 /* if there is enough in the buffer from a previous read, take some */
188 if (left >= n) {
189 s->packet_length += n;
190 rb->left = left - n;
191 rb->offset += n;
192 return n;
193 }
194
195 /* else we need to read more data */
196
197 len = s->packet_length;
198 pkt = rb->buf + align;
199 /* Move any available bytes to front of buffer: |len| bytes already pointed
200 * to by |packet|, |left| extra ones at the end. */
201 if (s->packet != pkt) {
202 /* len > 0 */
203 memmove(pkt, s->packet, len + left);
204 s->packet = pkt;
205 rb->offset = len + align;
206 }
207
208 if (n > (int)(rb->len - rb->offset)) {
209 OPENSSL_PUT_ERROR(SSL, ssl3_read_n, ERR_R_INTERNAL_ERROR);
210 return -1;
211 }
212
213 int max = n;
214 if (SSL_IS_DTLS(s) && !extend) {
215 max = rb->len - rb->offset;
216 }
217
218 while (left < n) {
219 /* Now we have len+left bytes at the front of s->s3->rbuf.buf and need to
220 * read in more until we have len+n (up to len+max if possible). */
221 ERR_clear_system_error();
222 if (s->rbio != NULL) {
223 s->rwstate = SSL_READING;
224 i = BIO_read(s->rbio, pkt + len + left, max - left);
225 } else {
226 OPENSSL_PUT_ERROR(SSL, ssl3_read_n, SSL_R_READ_BIO_NOT_SET);
227 i = -1;
228 }
229
230 if (i <= 0) {
231 rb->left = left;
232 if (len + left == 0) {
233 ssl3_release_read_buffer(s);
234 }
235 return i;
236 }
237 left += i;
238 /* reads should *never* span multiple packets for DTLS because the
239 * underlying transport protocol is message oriented as opposed to byte
240 * oriented as in the TLS case. */
241 if (SSL_IS_DTLS(s) && n > left) {
242 n = left; /* makes the while condition false */
243 }
244 }
245
246 /* done reading, now the book-keeping */
247 rb->offset += n;
248 rb->left = left - n;
249 s->packet_length += n;
250 s->rwstate = SSL_NOTHING;
251
252 return n;
253 }
254
255 /* MAX_EMPTY_RECORDS defines the number of consecutive, empty records that will
256 * be processed per call to ssl3_get_record. Without this limit an attacker
257 * could send empty records at a faster rate than we can process and cause
258 * ssl3_get_record to loop forever. */
259 #define MAX_EMPTY_RECORDS 32
260
261 /* Call this to get a new input record. It will return <= 0 if more data is
262 * needed, normally due to an error or non-blocking IO. When it finishes, one
263 * packet has been decoded and can be found in
264 * ssl->s3->rrec.type - is the type of record
265 * ssl->s3->rrec.data - data
266 * ssl->s3->rrec.length - number of bytes */
267 /* used only by ssl3_read_bytes */
ssl3_get_record(SSL * s)268 static int ssl3_get_record(SSL *s) {
269 uint8_t ssl_major, ssl_minor;
270 int al, n, i, ret = -1;
271 SSL3_RECORD *rr = &s->s3->rrec;
272 uint8_t *p;
273 uint16_t version;
274 size_t extra;
275 unsigned empty_record_count = 0;
276
277 again:
278 /* check if we have the header */
279 if (s->rstate != SSL_ST_READ_BODY ||
280 s->packet_length < SSL3_RT_HEADER_LENGTH) {
281 n = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, 0);
282 if (n <= 0) {
283 return n; /* error or non-blocking */
284 }
285 s->rstate = SSL_ST_READ_BODY;
286
287 /* Some bytes were read, so the read buffer must be existant and
288 * |s->s3->init_extra| is defined. */
289 assert(s->s3->rbuf.buf != NULL);
290 extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0;
291
292 p = s->packet;
293 if (s->msg_callback) {
294 s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s, s->msg_callback_arg);
295 }
296
297 /* Pull apart the header into the SSL3_RECORD */
298 rr->type = *(p++);
299 ssl_major = *(p++);
300 ssl_minor = *(p++);
301 version = (((uint16_t)ssl_major) << 8) | ssl_minor;
302 n2s(p, rr->length);
303
304 if (s->s3->have_version && version != s->version) {
305 OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
306 al = SSL_AD_PROTOCOL_VERSION;
307 goto f_err;
308 }
309
310 if ((version >> 8) != SSL3_VERSION_MAJOR) {
311 OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
312 goto err;
313 }
314
315 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH + extra) {
316 al = SSL_AD_RECORD_OVERFLOW;
317 OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
318 goto f_err;
319 }
320
321 /* now s->rstate == SSL_ST_READ_BODY */
322 } else {
323 /* |packet_length| is non-zero and |s->rstate| is |SSL_ST_READ_BODY|. The
324 * read buffer must be existant and |s->s3->init_extra| is defined. */
325 assert(s->s3->rbuf.buf != NULL);
326 extra = s->s3->init_extra ? SSL3_RT_MAX_EXTRA : 0;
327 }
328
329 /* s->rstate == SSL_ST_READ_BODY, get and decode the data */
330
331 if (rr->length > s->packet_length - SSL3_RT_HEADER_LENGTH) {
332 /* now s->packet_length == SSL3_RT_HEADER_LENGTH */
333 i = rr->length;
334 n = ssl3_read_n(s, i, 1);
335 if (n <= 0) {
336 /* Error or non-blocking IO. Now |n| == |rr->length|, and
337 * |s->packet_length| == |SSL3_RT_HEADER_LENGTH| + |rr->length|. */
338 return n;
339 }
340 }
341
342 s->rstate = SSL_ST_READ_HEADER; /* set state for later operations */
343
344 /* |rr->data| points to |rr->length| bytes of ciphertext in |s->packet|. */
345 rr->data = &s->packet[SSL3_RT_HEADER_LENGTH];
346
347 /* Decrypt the packet in-place.
348 *
349 * TODO(davidben): This assumes |s->version| is the same as the record-layer
350 * version which isn't always true, but it only differs with the NULL cipher
351 * which ignores the parameter. */
352 size_t plaintext_len;
353 if (!SSL_AEAD_CTX_open(s->aead_read_ctx, rr->data, &plaintext_len, rr->length,
354 rr->type, s->version, s->s3->read_sequence, rr->data,
355 rr->length)) {
356 al = SSL_AD_BAD_RECORD_MAC;
357 OPENSSL_PUT_ERROR(SSL, ssl3_get_record,
358 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
359 goto f_err;
360 }
361 if (!ssl3_record_sequence_update(s->s3->read_sequence, 8)) {
362 goto err;
363 }
364 if (plaintext_len > SSL3_RT_MAX_PLAIN_LENGTH + extra) {
365 al = SSL_AD_RECORD_OVERFLOW;
366 OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DATA_LENGTH_TOO_LONG);
367 goto f_err;
368 }
369 assert(plaintext_len <= (1u << 16));
370 rr->length = plaintext_len;
371
372 rr->off = 0;
373 /* So at this point the following is true:
374 * ssl->s3->rrec.type is the type of record;
375 * ssl->s3->rrec.length is the number of bytes in the record;
376 * ssl->s3->rrec.off is the offset to first valid byte;
377 * ssl->s3->rrec.data the first byte of the record body. */
378
379 /* we have pulled in a full packet so zero things */
380 s->packet_length = 0;
381
382 /* just read a 0 length packet */
383 if (rr->length == 0) {
384 empty_record_count++;
385 if (empty_record_count > MAX_EMPTY_RECORDS) {
386 al = SSL_AD_UNEXPECTED_MESSAGE;
387 OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_TOO_MANY_EMPTY_FRAGMENTS);
388 goto f_err;
389 }
390 goto again;
391 }
392
393 return 1;
394
395 f_err:
396 ssl3_send_alert(s, SSL3_AL_FATAL, al);
397 err:
398 return ret;
399 }
400
ssl3_write_app_data(SSL * ssl,const void * buf,int len)401 int ssl3_write_app_data(SSL *ssl, const void *buf, int len) {
402 return ssl3_write_bytes(ssl, SSL3_RT_APPLICATION_DATA, buf, len);
403 }
404
405 /* Call this to write data in records of type |type|. It will return <= 0 if
406 * not all data has been sent or non-blocking IO. */
ssl3_write_bytes(SSL * s,int type,const void * buf_,int len)407 int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len) {
408 const uint8_t *buf = buf_;
409 unsigned int tot, n, nw;
410 int i;
411
412 s->rwstate = SSL_NOTHING;
413 assert(s->s3->wnum <= INT_MAX);
414 tot = s->s3->wnum;
415 s->s3->wnum = 0;
416
417 if (!s->in_handshake && SSL_in_init(s) && !SSL_in_false_start(s)) {
418 i = s->handshake_func(s);
419 if (i < 0) {
420 return i;
421 }
422 if (i == 0) {
423 OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
424 return -1;
425 }
426 }
427
428 /* Ensure that if we end up with a smaller value of data to write out than
429 * the the original len from a write which didn't complete for non-blocking
430 * I/O and also somehow ended up avoiding the check for this in
431 * ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as it must never be possible to
432 * end up with (len-tot) as a large number that will then promptly send
433 * beyond the end of the users buffer ... so we trap and report the error in
434 * a way the user will notice. */
435 if (len < 0 || (size_t)len < tot) {
436 OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_BAD_LENGTH);
437 return -1;
438 }
439
440 int record_split_done = 0;
441 n = (len - tot);
442 for (;;) {
443 /* max contains the maximum number of bytes that we can put into a
444 * record. */
445 unsigned max = s->max_send_fragment;
446 /* fragment is true if do_ssl3_write should send the first byte in its own
447 * record in order to randomise a CBC IV. */
448 int fragment = 0;
449 if (!record_split_done && s->s3->need_record_splitting &&
450 type == SSL3_RT_APPLICATION_DATA) {
451 /* Only the the first record per write call needs to be split. The
452 * remaining plaintext was determined before the IV was randomized. */
453 fragment = 1;
454 record_split_done = 1;
455 }
456 if (n > max) {
457 nw = max;
458 } else {
459 nw = n;
460 }
461
462 i = do_ssl3_write(s, type, &buf[tot], nw, fragment);
463 if (i <= 0) {
464 s->s3->wnum = tot;
465 return i;
466 }
467
468 if (i == (int)n || (type == SSL3_RT_APPLICATION_DATA &&
469 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE))) {
470 return tot + i;
471 }
472
473 n -= i;
474 tot += i;
475 }
476 }
477
478 /* ssl3_seal_record seals a new record of type |type| and plaintext |in| and
479 * writes it to |out|. At most |max_out| bytes will be written. It returns one
480 * on success and zero on error. On success, it updates the write sequence
481 * number. */
ssl3_seal_record(SSL * s,uint8_t * out,size_t * out_len,size_t max_out,uint8_t type,const uint8_t * in,size_t in_len)482 static int ssl3_seal_record(SSL *s, uint8_t *out, size_t *out_len,
483 size_t max_out, uint8_t type, const uint8_t *in,
484 size_t in_len) {
485 if (max_out < SSL3_RT_HEADER_LENGTH) {
486 OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, SSL_R_BUFFER_TOO_SMALL);
487 return 0;
488 }
489
490 out[0] = type;
491
492 /* Some servers hang if initial ClientHello is larger than 256 bytes and
493 * record version number > TLS 1.0. */
494 uint16_t wire_version = s->version;
495 if (!s->s3->have_version && s->version > SSL3_VERSION) {
496 wire_version = TLS1_VERSION;
497 }
498 out[1] = wire_version >> 8;
499 out[2] = wire_version & 0xff;
500
501 size_t ciphertext_len;
502 if (!SSL_AEAD_CTX_seal(s->aead_write_ctx, out + SSL3_RT_HEADER_LENGTH,
503 &ciphertext_len, max_out - SSL3_RT_HEADER_LENGTH,
504 type, wire_version, s->s3->write_sequence, in,
505 in_len) ||
506 !ssl3_record_sequence_update(s->s3->write_sequence, 8)) {
507 return 0;
508 }
509
510 if (ciphertext_len >= 1 << 16) {
511 OPENSSL_PUT_ERROR(SSL, ssl3_seal_record, ERR_R_OVERFLOW);
512 return 0;
513 }
514 out[3] = ciphertext_len >> 8;
515 out[4] = ciphertext_len & 0xff;
516
517 *out_len = SSL3_RT_HEADER_LENGTH + ciphertext_len;
518
519 if (s->msg_callback) {
520 s->msg_callback(1 /* write */, 0, SSL3_RT_HEADER, out, SSL3_RT_HEADER_LENGTH,
521 s, s->msg_callback_arg);
522 }
523
524 return 1;
525 }
526
527 /* do_ssl3_write writes an SSL record of the given type. If |fragment| is 1
528 * then it splits the record into a one byte record and a record with the rest
529 * of the data in order to randomise a CBC IV. */
do_ssl3_write(SSL * s,int type,const uint8_t * buf,unsigned int len,char fragment)530 static int do_ssl3_write(SSL *s, int type, const uint8_t *buf, unsigned int len,
531 char fragment) {
532 SSL3_BUFFER *wb = &s->s3->wbuf;
533
534 /* first check if there is a SSL3_BUFFER still being written out. This will
535 * happen with non blocking IO */
536 if (wb->left != 0) {
537 return ssl3_write_pending(s, type, buf, len);
538 }
539
540 /* If we have an alert to send, lets send it */
541 if (s->s3->alert_dispatch) {
542 int ret = s->method->ssl_dispatch_alert(s);
543 if (ret <= 0) {
544 return ret;
545 }
546 /* if it went, fall through and send more stuff */
547 }
548
549 if (wb->buf == NULL && !ssl3_setup_write_buffer(s)) {
550 return -1;
551 }
552
553 if (len == 0) {
554 return 0;
555 }
556 if (len == 1) {
557 /* No sense in fragmenting a one-byte record. */
558 fragment = 0;
559 }
560
561 /* Align the output so the ciphertext is aligned to |SSL3_ALIGN_PAYLOAD|. */
562 uintptr_t align;
563 if (fragment) {
564 /* Only CBC-mode ciphers require fragmenting. CBC-mode ciphertext is a
565 * multiple of the block size which we may assume is aligned. Thus we only
566 * need to account for a second copy of the record header. */
567 align = (uintptr_t)wb->buf + 2 * SSL3_RT_HEADER_LENGTH;
568 } else {
569 align = (uintptr_t)wb->buf + SSL3_RT_HEADER_LENGTH;
570 }
571 align = (0 - align) & (SSL3_ALIGN_PAYLOAD - 1);
572 uint8_t *out = wb->buf + align;
573 wb->offset = align;
574 size_t max_out = wb->len - wb->offset;
575
576 const uint8_t *orig_buf = buf;
577 unsigned int orig_len = len;
578 size_t fragment_len = 0;
579 if (fragment) {
580 /* Write the first byte in its own record as a countermeasure against
581 * known-IV weaknesses in CBC ciphersuites. (See
582 * http://www.openssl.org/~bodo/tls-cbc.txt.) */
583 if (!ssl3_seal_record(s, out, &fragment_len, max_out, type, buf, 1)) {
584 return -1;
585 }
586 out += fragment_len;
587 max_out -= fragment_len;
588 buf++;
589 len--;
590 }
591
592 assert((((uintptr_t)out + SSL3_RT_HEADER_LENGTH) & (SSL3_ALIGN_PAYLOAD - 1))
593 == 0);
594 size_t ciphertext_len;
595 if (!ssl3_seal_record(s, out, &ciphertext_len, max_out, type, buf, len)) {
596 return -1;
597 }
598 ciphertext_len += fragment_len;
599
600 /* now let's set up wb */
601 wb->left = ciphertext_len;
602
603 /* memorize arguments so that ssl3_write_pending can detect bad write retries
604 * later */
605 s->s3->wpend_tot = orig_len;
606 s->s3->wpend_buf = orig_buf;
607 s->s3->wpend_type = type;
608 s->s3->wpend_ret = orig_len;
609
610 /* we now just need to write the buffer */
611 return ssl3_write_pending(s, type, orig_buf, orig_len);
612 }
613
614 /* if s->s3->wbuf.left != 0, we need to call this */
ssl3_write_pending(SSL * s,int type,const uint8_t * buf,unsigned int len)615 int ssl3_write_pending(SSL *s, int type, const uint8_t *buf, unsigned int len) {
616 int i;
617 SSL3_BUFFER *wb = &(s->s3->wbuf);
618
619 if (s->s3->wpend_tot > (int)len ||
620 (s->s3->wpend_buf != buf &&
621 !(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)) ||
622 s->s3->wpend_type != type) {
623 OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BAD_WRITE_RETRY);
624 return -1;
625 }
626
627 for (;;) {
628 ERR_clear_system_error();
629 if (s->wbio != NULL) {
630 s->rwstate = SSL_WRITING;
631 i = BIO_write(s->wbio, (char *)&(wb->buf[wb->offset]),
632 (unsigned int)wb->left);
633 } else {
634 OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BIO_NOT_SET);
635 i = -1;
636 }
637 if (i == wb->left) {
638 wb->left = 0;
639 wb->offset += i;
640 ssl3_release_write_buffer(s);
641 s->rwstate = SSL_NOTHING;
642 return s->s3->wpend_ret;
643 } else if (i <= 0) {
644 if (SSL_IS_DTLS(s)) {
645 /* For DTLS, just drop it. That's kind of the whole point in
646 * using a datagram service */
647 wb->left = 0;
648 }
649 return i;
650 }
651 /* TODO(davidben): This codepath is used in DTLS, but the write
652 * payload may not split across packets. */
653 wb->offset += i;
654 wb->left -= i;
655 }
656 }
657
658 /* ssl3_expect_change_cipher_spec informs the record layer that a
659 * ChangeCipherSpec record is required at this point. If a Handshake record is
660 * received before ChangeCipherSpec, the connection will fail. Moreover, if
661 * there are unprocessed handshake bytes, the handshake will also fail and the
662 * function returns zero. Otherwise, the function returns one. */
ssl3_expect_change_cipher_spec(SSL * s)663 int ssl3_expect_change_cipher_spec(SSL *s) {
664 if (s->s3->handshake_fragment_len > 0 || s->s3->tmp.reuse_message) {
665 OPENSSL_PUT_ERROR(SSL, ssl3_expect_change_cipher_spec,
666 SSL_R_UNPROCESSED_HANDSHAKE_DATA);
667 return 0;
668 }
669
670 s->s3->flags |= SSL3_FLAGS_EXPECT_CCS;
671 return 1;
672 }
673
ssl3_read_app_data(SSL * ssl,uint8_t * buf,int len,int peek)674 int ssl3_read_app_data(SSL *ssl, uint8_t *buf, int len, int peek) {
675 return ssl3_read_bytes(ssl, SSL3_RT_APPLICATION_DATA, buf, len, peek);
676 }
677
ssl3_read_close_notify(SSL * ssl)678 void ssl3_read_close_notify(SSL *ssl) {
679 ssl3_read_bytes(ssl, 0, NULL, 0, 0);
680 }
681
682 /* Return up to 'len' payload bytes received in 'type' records.
683 * 'type' is one of the following:
684 *
685 * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
686 * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
687 * - 0 (during a shutdown, no data has to be returned)
688 *
689 * If we don't have stored data to work from, read a SSL/TLS record first
690 * (possibly multiple records if we still don't have anything to return).
691 *
692 * This function must handle any surprises the peer may have for us, such as
693 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
694 * a surprise, but handled as if it were), or renegotiation requests.
695 * Also if record payloads contain fragments too small to process, we store
696 * them until there is enough for the respective protocol (the record protocol
697 * may use arbitrary fragmentation and even interleaving):
698 * Change cipher spec protocol
699 * just 1 byte needed, no need for keeping anything stored
700 * Alert protocol
701 * 2 bytes needed (AlertLevel, AlertDescription)
702 * Handshake protocol
703 * 4 bytes needed (HandshakeType, uint24 length) -- we just have
704 * to detect unexpected Client Hello and Hello Request messages
705 * here, anything else is handled by higher layers
706 * Application data protocol
707 * none of our business
708 */
ssl3_read_bytes(SSL * s,int type,uint8_t * buf,int len,int peek)709 int ssl3_read_bytes(SSL *s, int type, uint8_t *buf, int len, int peek) {
710 int al, i, ret;
711 unsigned int n;
712 SSL3_RECORD *rr;
713 void (*cb)(const SSL *ssl, int type2, int val) = NULL;
714
715 if ((type && type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) ||
716 (peek && type != SSL3_RT_APPLICATION_DATA)) {
717 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR);
718 return -1;
719 }
720
721 if (type == SSL3_RT_HANDSHAKE && s->s3->handshake_fragment_len > 0) {
722 /* (partially) satisfy request from storage */
723 uint8_t *src = s->s3->handshake_fragment;
724 uint8_t *dst = buf;
725 unsigned int k;
726
727 /* peek == 0 */
728 n = 0;
729 while (len > 0 && s->s3->handshake_fragment_len > 0) {
730 *dst++ = *src++;
731 len--;
732 s->s3->handshake_fragment_len--;
733 n++;
734 }
735 /* move any remaining fragment bytes: */
736 for (k = 0; k < s->s3->handshake_fragment_len; k++) {
737 s->s3->handshake_fragment[k] = *src++;
738 }
739 return n;
740 }
741
742 /* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
743
744 /* This may require multiple iterations. False Start will cause
745 * |s->handshake_func| to signal success one step early, but the handshake
746 * must be completely finished before other modes are accepted.
747 *
748 * TODO(davidben): Move this check up to a higher level. */
749 while (!s->in_handshake && SSL_in_init(s)) {
750 assert(type == SSL3_RT_APPLICATION_DATA);
751 i = s->handshake_func(s);
752 if (i < 0) {
753 return i;
754 }
755 if (i == 0) {
756 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
757 return -1;
758 }
759 }
760
761 start:
762 s->rwstate = SSL_NOTHING;
763
764 /* s->s3->rrec.type - is the type of record
765 * s->s3->rrec.data - data
766 * s->s3->rrec.off - offset into 'data' for next read
767 * s->s3->rrec.length - number of bytes. */
768 rr = &s->s3->rrec;
769
770 /* get new packet if necessary */
771 if (rr->length == 0 || s->rstate == SSL_ST_READ_BODY) {
772 ret = ssl3_get_record(s);
773 if (ret <= 0) {
774 return ret;
775 }
776 }
777
778 /* we now have a packet which can be read and processed */
779
780 /* |change_cipher_spec is set when we receive a ChangeCipherSpec and reset by
781 * ssl3_get_finished. */
782 if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE &&
783 rr->type != SSL3_RT_ALERT) {
784 al = SSL_AD_UNEXPECTED_MESSAGE;
785 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes,
786 SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
787 goto f_err;
788 }
789
790 /* If we are expecting a ChangeCipherSpec, it is illegal to receive a
791 * Handshake record. */
792 if (rr->type == SSL3_RT_HANDSHAKE && (s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
793 al = SSL_AD_UNEXPECTED_MESSAGE;
794 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_HANDSHAKE_RECORD_BEFORE_CCS);
795 goto f_err;
796 }
797
798 /* If the other end has shut down, throw anything we read away (even in
799 * 'peek' mode) */
800 if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
801 rr->length = 0;
802 s->rwstate = SSL_NOTHING;
803 return 0;
804 }
805
806 if (type == rr->type) {
807 /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
808 /* make sure that we are not getting application data when we are doing a
809 * handshake for the first time */
810 if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA &&
811 s->aead_read_ctx == NULL) {
812 /* TODO(davidben): Is this check redundant with the handshake_func
813 * check? */
814 al = SSL_AD_UNEXPECTED_MESSAGE;
815 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_APP_DATA_IN_HANDSHAKE);
816 goto f_err;
817 }
818
819 if (len <= 0) {
820 return len;
821 }
822
823 if ((unsigned int)len > rr->length) {
824 n = rr->length;
825 } else {
826 n = (unsigned int)len;
827 }
828
829 memcpy(buf, &(rr->data[rr->off]), n);
830 if (!peek) {
831 rr->length -= n;
832 rr->off += n;
833 if (rr->length == 0) {
834 s->rstate = SSL_ST_READ_HEADER;
835 rr->off = 0;
836 if (s->s3->rbuf.left == 0) {
837 ssl3_release_read_buffer(s);
838 }
839 }
840 }
841
842 return n;
843 }
844
845 /* Process unexpected records. */
846
847 if (rr->type == SSL3_RT_HANDSHAKE) {
848 /* If peer renegotiations are disabled, all out-of-order handshake records
849 * are fatal. Renegotiations as a server are never supported. */
850 if (!s->accept_peer_renegotiations || s->server) {
851 al = SSL_AD_NO_RENEGOTIATION;
852 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
853 goto f_err;
854 }
855
856 /* HelloRequests may be fragmented across multiple records. */
857 const size_t size = sizeof(s->s3->handshake_fragment);
858 const size_t avail = size - s->s3->handshake_fragment_len;
859 const size_t todo = (rr->length < avail) ? rr->length : avail;
860 memcpy(s->s3->handshake_fragment + s->s3->handshake_fragment_len,
861 &rr->data[rr->off], todo);
862 rr->off += todo;
863 rr->length -= todo;
864 s->s3->handshake_fragment_len += todo;
865 if (s->s3->handshake_fragment_len < size) {
866 goto start; /* fragment was too small */
867 }
868
869 /* Parse out and consume a HelloRequest. */
870 if (s->s3->handshake_fragment[0] != SSL3_MT_HELLO_REQUEST ||
871 s->s3->handshake_fragment[1] != 0 ||
872 s->s3->handshake_fragment[2] != 0 ||
873 s->s3->handshake_fragment[3] != 0) {
874 al = SSL_AD_DECODE_ERROR;
875 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_HELLO_REQUEST);
876 goto f_err;
877 }
878 s->s3->handshake_fragment_len = 0;
879
880 if (s->msg_callback) {
881 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
882 s->s3->handshake_fragment, 4, s, s->msg_callback_arg);
883 }
884
885 if (!SSL_is_init_finished(s) || !s->s3->initial_handshake_complete) {
886 /* This cannot happen. If a handshake is in progress, |type| must be
887 * |SSL3_RT_HANDSHAKE|. */
888 assert(0);
889 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR);
890 goto err;
891 }
892
893 /* Renegotiation is only supported at quiescent points in the application
894 * protocol, namely in HTTPS, just before reading the HTTP response. Require
895 * the record-layer be idle and avoid complexities of sending a handshake
896 * record while an application_data record is being written. */
897 if (s->s3->wbuf.left != 0 || s->s3->rbuf.left != 0) {
898 al = SSL_AD_NO_RENEGOTIATION;
899 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
900 goto f_err;
901 }
902
903 /* Begin a new handshake. */
904 s->state = SSL_ST_CONNECT;
905 i = s->handshake_func(s);
906 if (i < 0) {
907 return i;
908 }
909 if (i == 0) {
910 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
911 return -1;
912 }
913
914 /* The handshake completed synchronously. Continue reading records. */
915 goto start;
916 }
917
918 /* If an alert record, process one alert out of the record. Note that we allow
919 * a single record to contain multiple alerts. */
920 if (rr->type == SSL3_RT_ALERT) {
921 /* Alerts may not be fragmented. */
922 if (rr->length < 2) {
923 al = SSL_AD_DECODE_ERROR;
924 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_ALERT);
925 goto f_err;
926 }
927
928 if (s->msg_callback) {
929 s->msg_callback(0, s->version, SSL3_RT_ALERT, &rr->data[rr->off], 2, s,
930 s->msg_callback_arg);
931 }
932 const uint8_t alert_level = rr->data[rr->off++];
933 const uint8_t alert_descr = rr->data[rr->off++];
934 rr->length -= 2;
935
936 if (s->info_callback != NULL) {
937 cb = s->info_callback;
938 } else if (s->ctx->info_callback != NULL) {
939 cb = s->ctx->info_callback;
940 }
941
942 if (cb != NULL) {
943 uint16_t alert = (alert_level << 8) | alert_descr;
944 cb(s, SSL_CB_READ_ALERT, alert);
945 }
946
947 if (alert_level == SSL3_AL_WARNING) {
948 s->s3->warn_alert = alert_descr;
949 if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
950 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
951 return 0;
952 }
953
954 /* This is a warning but we receive it if we requested renegotiation and
955 * the peer denied it. Terminate with a fatal alert because if
956 * application tried to renegotiatie it presumably had a good reason and
957 * expects it to succeed.
958 *
959 * In future we might have a renegotiation where we don't care if the
960 * peer refused it where we carry on. */
961 else if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
962 al = SSL_AD_HANDSHAKE_FAILURE;
963 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
964 goto f_err;
965 }
966 } else if (alert_level == SSL3_AL_FATAL) {
967 char tmp[16];
968
969 s->rwstate = SSL_NOTHING;
970 s->s3->fatal_alert = alert_descr;
971 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes,
972 SSL_AD_REASON_OFFSET + alert_descr);
973 BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr);
974 ERR_add_error_data(2, "SSL alert number ", tmp);
975 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
976 SSL_CTX_remove_session(s->ctx, s->session);
977 return 0;
978 } else {
979 al = SSL_AD_ILLEGAL_PARAMETER;
980 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNKNOWN_ALERT_TYPE);
981 goto f_err;
982 }
983
984 goto start;
985 }
986
987 if (s->shutdown & SSL_SENT_SHUTDOWN) {
988 /* but we have not received a shutdown */
989 s->rwstate = SSL_NOTHING;
990 rr->length = 0;
991 return 0;
992 }
993
994 if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
995 /* 'Change Cipher Spec' is just a single byte, so we know exactly what the
996 * record payload has to look like */
997 if (rr->length != 1 || rr->off != 0 || rr->data[0] != SSL3_MT_CCS) {
998 al = SSL_AD_ILLEGAL_PARAMETER;
999 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_CHANGE_CIPHER_SPEC);
1000 goto f_err;
1001 }
1002
1003 /* Check we have a cipher to change to */
1004 if (s->s3->tmp.new_cipher == NULL) {
1005 al = SSL_AD_UNEXPECTED_MESSAGE;
1006 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
1007 goto f_err;
1008 }
1009
1010 if (!(s->s3->flags & SSL3_FLAGS_EXPECT_CCS)) {
1011 al = SSL_AD_UNEXPECTED_MESSAGE;
1012 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
1013 goto f_err;
1014 }
1015
1016 s->s3->flags &= ~SSL3_FLAGS_EXPECT_CCS;
1017
1018 rr->length = 0;
1019
1020 if (s->msg_callback) {
1021 s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s,
1022 s->msg_callback_arg);
1023 }
1024
1025 s->s3->change_cipher_spec = 1;
1026 if (!ssl3_do_change_cipher_spec(s)) {
1027 goto err;
1028 } else {
1029 goto start;
1030 }
1031 }
1032
1033 /* We already handled these. */
1034 assert(rr->type != SSL3_RT_CHANGE_CIPHER_SPEC && rr->type != SSL3_RT_ALERT &&
1035 rr->type != SSL3_RT_HANDSHAKE);
1036
1037 al = SSL_AD_UNEXPECTED_MESSAGE;
1038 OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNEXPECTED_RECORD);
1039
1040 f_err:
1041 ssl3_send_alert(s, SSL3_AL_FATAL, al);
1042 err:
1043 return -1;
1044 }
1045
ssl3_do_change_cipher_spec(SSL * s)1046 int ssl3_do_change_cipher_spec(SSL *s) {
1047 int i;
1048
1049 if (s->state & SSL_ST_ACCEPT) {
1050 i = SSL3_CHANGE_CIPHER_SERVER_READ;
1051 } else {
1052 i = SSL3_CHANGE_CIPHER_CLIENT_READ;
1053 }
1054
1055 if (s->s3->tmp.key_block == NULL) {
1056 if (s->session == NULL || s->session->master_key_length == 0) {
1057 /* might happen if dtls1_read_bytes() calls this */
1058 OPENSSL_PUT_ERROR(SSL, ssl3_do_change_cipher_spec,
1059 SSL_R_CCS_RECEIVED_EARLY);
1060 return 0;
1061 }
1062
1063 s->session->cipher = s->s3->tmp.new_cipher;
1064 if (!s->enc_method->setup_key_block(s)) {
1065 return 0;
1066 }
1067 }
1068
1069 if (!s->enc_method->change_cipher_state(s, i)) {
1070 return 0;
1071 }
1072
1073 return 1;
1074 }
1075
ssl3_send_alert(SSL * s,int level,int desc)1076 int ssl3_send_alert(SSL *s, int level, int desc) {
1077 /* Map tls/ssl alert value to correct one */
1078 desc = s->enc_method->alert_value(desc);
1079 if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION) {
1080 /* SSL 3.0 does not have protocol_version alerts */
1081 desc = SSL_AD_HANDSHAKE_FAILURE;
1082 }
1083 if (desc < 0) {
1084 return -1;
1085 }
1086
1087 /* If a fatal one, remove from cache */
1088 if (level == 2 && s->session != NULL) {
1089 SSL_CTX_remove_session(s->ctx, s->session);
1090 }
1091
1092 s->s3->alert_dispatch = 1;
1093 s->s3->send_alert[0] = level;
1094 s->s3->send_alert[1] = desc;
1095 if (s->s3->wbuf.left == 0) {
1096 /* data is still being written out. */
1097 return s->method->ssl_dispatch_alert(s);
1098 }
1099
1100 /* else data is still being written out, we will get written some time in the
1101 * future */
1102 return -1;
1103 }
1104
ssl3_dispatch_alert(SSL * s)1105 int ssl3_dispatch_alert(SSL *s) {
1106 int i, j;
1107 void (*cb)(const SSL *ssl, int type, int val) = NULL;
1108
1109 s->s3->alert_dispatch = 0;
1110 i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0);
1111 if (i <= 0) {
1112 s->s3->alert_dispatch = 1;
1113 } else {
1114 /* Alert sent to BIO. If it is important, flush it now. If the message
1115 * does not get sent due to non-blocking IO, we will not worry too much. */
1116 if (s->s3->send_alert[0] == SSL3_AL_FATAL) {
1117 BIO_flush(s->wbio);
1118 }
1119
1120 if (s->msg_callback) {
1121 s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s,
1122 s->msg_callback_arg);
1123 }
1124
1125 if (s->info_callback != NULL) {
1126 cb = s->info_callback;
1127 } else if (s->ctx->info_callback != NULL) {
1128 cb = s->ctx->info_callback;
1129 }
1130
1131 if (cb != NULL) {
1132 j = (s->s3->send_alert[0] << 8) | s->s3->send_alert[1];
1133 cb(s, SSL_CB_WRITE_ALERT, j);
1134 }
1135 }
1136
1137 return i;
1138 }
1139