Deal with the unlikely event that EVP_MD_CTX_size() returns an error.
[openssl.git] / ssl / d1_pkt.c
1 /* ssl/d1_pkt.c */
2 /* 
3  * DTLS implementation written by Nagendra Modadugu
4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
5  */
6 /* ====================================================================
7  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer. 
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in
18  *    the documentation and/or other materials provided with the
19  *    distribution.
20  *
21  * 3. All advertising materials mentioning features or use of this
22  *    software must display the following acknowledgment:
23  *    "This product includes software developed by the OpenSSL Project
24  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
25  *
26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27  *    endorse or promote products derived from this software without
28  *    prior written permission. For written permission, please contact
29  *    openssl-core@openssl.org.
30  *
31  * 5. Products derived from this software may not be called "OpenSSL"
32  *    nor may "OpenSSL" appear in their names without prior written
33  *    permission of the OpenSSL Project.
34  *
35  * 6. Redistributions of any form whatsoever must retain the following
36  *    acknowledgment:
37  *    "This product includes software developed by the OpenSSL Project
38  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51  * OF THE POSSIBILITY OF SUCH DAMAGE.
52  * ====================================================================
53  *
54  * This product includes cryptographic software written by Eric Young
55  * (eay@cryptsoft.com).  This product includes software written by Tim
56  * Hudson (tjh@cryptsoft.com).
57  *
58  */
59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
60  * All rights reserved.
61  *
62  * This package is an SSL implementation written
63  * by Eric Young (eay@cryptsoft.com).
64  * The implementation was written so as to conform with Netscapes SSL.
65  * 
66  * This library is free for commercial and non-commercial use as long as
67  * the following conditions are aheared to.  The following conditions
68  * apply to all code found in this distribution, be it the RC4, RSA,
69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
70  * included with this distribution is covered by the same copyright terms
71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
72  * 
73  * Copyright remains Eric Young's, and as such any Copyright notices in
74  * the code are not to be removed.
75  * If this package is used in a product, Eric Young should be given attribution
76  * as the author of the parts of the library used.
77  * This can be in the form of a textual message at program startup or
78  * in documentation (online or textual) provided with the package.
79  * 
80  * Redistribution and use in source and binary forms, with or without
81  * modification, are permitted provided that the following conditions
82  * are met:
83  * 1. Redistributions of source code must retain the copyright
84  *    notice, this list of conditions and the following disclaimer.
85  * 2. Redistributions in binary form must reproduce the above copyright
86  *    notice, this list of conditions and the following disclaimer in the
87  *    documentation and/or other materials provided with the distribution.
88  * 3. All advertising materials mentioning features or use of this software
89  *    must display the following acknowledgement:
90  *    "This product includes cryptographic software written by
91  *     Eric Young (eay@cryptsoft.com)"
92  *    The word 'cryptographic' can be left out if the rouines from the library
93  *    being used are not cryptographic related :-).
94  * 4. If you include any Windows specific code (or a derivative thereof) from 
95  *    the apps directory (application code) you must include an acknowledgement:
96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
97  * 
98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
108  * SUCH DAMAGE.
109  * 
110  * The licence and distribution terms for any publically available version or
111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
112  * copied and put under another distribution licence
113  * [including the GNU Public Licence.]
114  */
115
116 #include <stdio.h>
117 #include <errno.h>
118 #define USE_SOCKETS
119 #include "ssl_locl.h"
120 #include <openssl/evp.h>
121 #include <openssl/buffer.h>
122 #include <openssl/pqueue.h>
123 #include <openssl/rand.h>
124
125 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
126 static int satsub64be(const unsigned char *v1,const unsigned char *v2)
127 {       int ret,sat,brw,i;
128
129         if (sizeof(long) == 8) do
130         {       const union { long one; char little; } is_endian = {1};
131                 long l;
132
133                 if (is_endian.little)                   break;
134                 /* not reached on little-endians */
135                 /* following test is redundant, because input is
136                  * always aligned, but I take no chances... */
137                 if (((size_t)v1|(size_t)v2)&0x7)        break;
138
139                 l  = *((long *)v1);
140                 l -= *((long *)v2);
141                 if (l>128)              return 128;
142                 else if (l<-128)        return -128;
143                 else                    return (int)l;
144         } while (0);
145
146         ret = (int)v1[7]-(int)v2[7];
147         sat = 0;
148         brw = ret>>8;   /* brw is either 0 or -1 */
149         if (ret & 0x80)
150         {       for (i=6;i>=0;i--)
151                 {       brw += (int)v1[i]-(int)v2[i];
152                         sat |= ~brw;
153                         brw >>= 8;
154                 }
155         }
156         else
157         {       for (i=6;i>=0;i--)
158                 {       brw += (int)v1[i]-(int)v2[i];
159                         sat |= brw;
160                         brw >>= 8;
161                 }
162         }
163         brw <<= 8;      /* brw is either 0 or -256 */
164
165         if (sat&0xff)   return brw | 0x80;
166         else            return brw + (ret&0xFF);
167 }
168
169 static int have_handshake_fragment(SSL *s, int type, unsigned char *buf, 
170         int len, int peek);
171 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap);
172 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap);
173 static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, 
174     unsigned int *is_next_epoch);
175 #if 0
176 static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
177         unsigned short *priority, unsigned long *offset);
178 #endif
179 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
180         unsigned char *priority);
181 static int dtls1_process_record(SSL *s);
182 static void dtls1_clear_timeouts(SSL *s);
183
184 /* copy buffered record into SSL structure */
185 static int
186 dtls1_copy_record(SSL *s, pitem *item)
187     {
188     DTLS1_RECORD_DATA *rdata;
189
190     rdata = (DTLS1_RECORD_DATA *)item->data;
191     
192     if (s->s3->rbuf.buf != NULL)
193         OPENSSL_free(s->s3->rbuf.buf);
194     
195     s->packet = rdata->packet;
196     s->packet_length = rdata->packet_length;
197     memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
198     memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
199     
200     return(1);
201     }
202
203
204 static int
205 dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority)
206         {
207         DTLS1_RECORD_DATA *rdata;
208         pitem *item;
209
210         rdata = OPENSSL_malloc(sizeof(DTLS1_RECORD_DATA));
211         item = pitem_new(priority, rdata);
212         if (rdata == NULL || item == NULL)
213                 {
214                 if (rdata != NULL) OPENSSL_free(rdata);
215                 if (item != NULL) pitem_free(item);
216                 
217                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
218                 return(0);
219                 }
220         
221         rdata->packet = s->packet;
222         rdata->packet_length = s->packet_length;
223         memcpy(&(rdata->rbuf), &(s->s3->rbuf), sizeof(SSL3_BUFFER));
224         memcpy(&(rdata->rrec), &(s->s3->rrec), sizeof(SSL3_RECORD));
225
226         item->data = rdata;
227
228         /* insert should not fail, since duplicates are dropped */
229         if (pqueue_insert(queue->q, item) == NULL)
230                 {
231                 OPENSSL_free(rdata);
232                 pitem_free(item);
233                 return(0);
234                 }
235
236         s->packet = NULL;
237         s->packet_length = 0;
238         memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER));
239         memset(&(s->s3->rrec), 0, sizeof(SSL3_RECORD));
240         
241         if (!ssl3_setup_buffers(s))
242                 {
243                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
244                 OPENSSL_free(rdata);
245                 pitem_free(item);
246                 return(0);
247                 }
248         
249         return(1);
250         }
251
252
253 static int
254 dtls1_retrieve_buffered_record(SSL *s, record_pqueue *queue)
255     {
256     pitem *item;
257
258     item = pqueue_pop(queue->q);
259     if (item)
260         {
261         dtls1_copy_record(s, item);
262
263         OPENSSL_free(item->data);
264                 pitem_free(item);
265
266         return(1);
267         }
268
269     return(0);
270     }
271
272
273 /* retrieve a buffered record that belongs to the new epoch, i.e., not processed 
274  * yet */
275 #define dtls1_get_unprocessed_record(s) \
276                    dtls1_retrieve_buffered_record((s), \
277                    &((s)->d1->unprocessed_rcds))
278
279 /* retrieve a buffered record that belongs to the current epoch, ie, processed */
280 #define dtls1_get_processed_record(s) \
281                    dtls1_retrieve_buffered_record((s), \
282                    &((s)->d1->processed_rcds))
283
284 static int
285 dtls1_process_buffered_records(SSL *s)
286     {
287     pitem *item;
288     
289     item = pqueue_peek(s->d1->unprocessed_rcds.q);
290     if (item)
291         {
292         DTLS1_RECORD_DATA *rdata;
293         rdata = (DTLS1_RECORD_DATA *)item->data;
294         
295         /* Check if epoch is current. */
296         if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
297             return(1);  /* Nothing to do. */
298         
299         /* Process all the records. */
300         while (pqueue_peek(s->d1->unprocessed_rcds.q))
301             {
302             dtls1_get_unprocessed_record(s);
303             if ( ! dtls1_process_record(s))
304                 return(0);
305             dtls1_buffer_record(s, &(s->d1->processed_rcds), 
306                 s->s3->rrec.seq_num);
307             }
308         }
309
310     /* sync epoch numbers once all the unprocessed records 
311      * have been processed */
312     s->d1->processed_rcds.epoch = s->d1->r_epoch;
313     s->d1->unprocessed_rcds.epoch = s->d1->r_epoch + 1;
314
315     return(1);
316     }
317
318
319 #if 0
320
321 static int
322 dtls1_get_buffered_record(SSL *s)
323         {
324         pitem *item;
325         PQ_64BIT priority = 
326                 (((PQ_64BIT)s->d1->handshake_read_seq) << 32) | 
327                 ((PQ_64BIT)s->d1->r_msg_hdr.frag_off);
328         
329         if ( ! SSL_in_init(s))  /* if we're not (re)negotiating, 
330                                                            nothing buffered */
331                 return 0;
332
333
334         item = pqueue_peek(s->d1->rcvd_records);
335         if (item && item->priority == priority)
336                 {
337                 /* Check if we've received the record of interest.  It must be
338                  * a handshake record, since data records as passed up without
339                  * buffering */
340                 DTLS1_RECORD_DATA *rdata;
341                 item = pqueue_pop(s->d1->rcvd_records);
342                 rdata = (DTLS1_RECORD_DATA *)item->data;
343                 
344                 if (s->s3->rbuf.buf != NULL)
345                         OPENSSL_free(s->s3->rbuf.buf);
346                 
347                 s->packet = rdata->packet;
348                 s->packet_length = rdata->packet_length;
349                 memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
350                 memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
351                 
352                 OPENSSL_free(item->data);
353                 pitem_free(item);
354                 
355                 /* s->d1->next_expected_seq_num++; */
356                 return(1);
357                 }
358         
359         return 0;
360         }
361
362 #endif
363
364 static int
365 dtls1_process_record(SSL *s)
366 {
367         int i,al;
368         int clear=0;
369         int enc_err;
370         SSL_SESSION *sess;
371         SSL3_RECORD *rr;
372         unsigned int mac_size;
373         unsigned char md[EVP_MAX_MD_SIZE];
374
375
376         rr= &(s->s3->rrec);
377         sess = s->session;
378
379         /* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
380          * and we have that many bytes in s->packet
381          */
382         rr->input= &(s->packet[DTLS1_RT_HEADER_LENGTH]);
383
384         /* ok, we can now read from 's->packet' data into 'rr'
385          * rr->input points at rr->length bytes, which
386          * need to be copied into rr->data by either
387          * the decryption or by the decompression
388          * When the data is 'copied' into the rr->data buffer,
389          * rr->input will be pointed at the new buffer */ 
390
391         /* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
392          * rr->length bytes of encrypted compressed stuff. */
393
394         /* check is not needed I believe */
395         if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
396                 {
397                 al=SSL_AD_RECORD_OVERFLOW;
398                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
399                 goto f_err;
400                 }
401
402         /* decrypt in place in 'rr->input' */
403         rr->data=rr->input;
404
405         enc_err = s->method->ssl3_enc->enc(s,0);
406         if (enc_err <= 0)
407                 {
408                 if (enc_err == 0)
409                         /* SSLerr() and ssl3_send_alert() have been called */
410                         goto err;
411
412                 /* otherwise enc_err == -1 */
413                 goto decryption_failed_or_bad_record_mac;
414                 }
415
416 #ifdef TLS_DEBUG
417 printf("dec %d\n",rr->length);
418 { unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
419 printf("\n");
420 #endif
421
422         /* r->length is now the compressed data plus mac */
423         if (    (sess == NULL) ||
424                 (s->enc_read_ctx == NULL) ||
425                 (s->read_hash == NULL))
426         clear=1;
427
428         if (!clear)
429                 {
430                 mac_size=EVP_MD_CTX_size(s->read_hash);
431                 if (mac_size <= 0)
432                         {
433                         al=SSL_AD_INTERNAL_ERROR;
434                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_BAD_MAC_LENGTH);
435                         goto f_err;
436                         }
437
438                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
439                         {
440 #if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
441                         al=SSL_AD_RECORD_OVERFLOW;
442                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
443                         goto f_err;
444 #else
445                         goto decryption_failed_or_bad_record_mac;
446 #endif                  
447                         }
448                 /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
449                 if (rr->length < mac_size)
450                         {
451 #if 0 /* OK only for stream ciphers */
452                         al=SSL_AD_DECODE_ERROR;
453                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
454                         goto f_err;
455 #else
456                         goto decryption_failed_or_bad_record_mac;
457 #endif
458                         }
459                 rr->length-=mac_size;
460                 i=s->method->ssl3_enc->mac(s,md,0);
461                 if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
462                         {
463                         goto decryption_failed_or_bad_record_mac;
464                         }
465                 }
466
467         /* r->length is now just compressed */
468         if (s->expand != NULL)
469                 {
470                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH)
471                         {
472                         al=SSL_AD_RECORD_OVERFLOW;
473                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
474                         goto f_err;
475                         }
476                 if (!ssl3_do_uncompress(s))
477                         {
478                         al=SSL_AD_DECOMPRESSION_FAILURE;
479                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_BAD_DECOMPRESSION);
480                         goto f_err;
481                         }
482                 }
483
484         if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH)
485                 {
486                 al=SSL_AD_RECORD_OVERFLOW;
487                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
488                 goto f_err;
489                 }
490
491         rr->off=0;
492         /* So at this point the following is true
493          * ssl->s3->rrec.type   is the type of record
494          * ssl->s3->rrec.length == number of bytes in record
495          * ssl->s3->rrec.off    == offset to first valid byte
496          * ssl->s3->rrec.data   == where to take bytes from, increment
497          *                         after use :-).
498          */
499
500         /* we have pulled in a full packet so zero things */
501         s->packet_length=0;
502         dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
503         return(1);
504
505 decryption_failed_or_bad_record_mac:
506         /* Separate 'decryption_failed' alert was introduced with TLS 1.0,
507          * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
508          * failure is directly visible from the ciphertext anyway,
509          * we should not reveal which kind of error occured -- this
510          * might become visible to an attacker (e.g. via logfile) */
511         al=SSL_AD_BAD_RECORD_MAC;
512         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
513 f_err:
514         ssl3_send_alert(s,SSL3_AL_FATAL,al);
515 err:
516         return(0);
517 }
518
519
520 /* Call this to get a new input record.
521  * It will return <= 0 if more data is needed, normally due to an error
522  * or non-blocking IO.
523  * When it finishes, one packet has been decoded and can be found in
524  * ssl->s3->rrec.type    - is the type of record
525  * ssl->s3->rrec.data,   - data
526  * ssl->s3->rrec.length, - number of bytes
527  */
528 /* used only by dtls1_read_bytes */
529 int dtls1_get_record(SSL *s)
530         {
531         int ssl_major,ssl_minor,al;
532         int i,n;
533         SSL3_RECORD *rr;
534         SSL_SESSION *sess;
535         unsigned char *p;
536         unsigned short version;
537         DTLS1_BITMAP *bitmap;
538         unsigned int is_next_epoch;
539
540         rr= &(s->s3->rrec);
541         sess=s->session;
542
543         /* The epoch may have changed.  If so, process all the
544          * pending records.  This is a non-blocking operation. */
545         if ( ! dtls1_process_buffered_records(s))
546             return 0;
547
548         /* if we're renegotiating, then there may be buffered records */
549         if (dtls1_get_processed_record(s))
550                 return 1;
551
552         /* get something from the wire */
553 again:
554         /* check if we have the header */
555         if (    (s->rstate != SSL_ST_READ_BODY) ||
556                 (s->packet_length < DTLS1_RT_HEADER_LENGTH)) 
557                 {
558                 n=ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
559                 /* read timeout is handled by dtls1_read_bytes */
560                 if (n <= 0) return(n); /* error or non-blocking */
561
562                 OPENSSL_assert(s->packet_length == DTLS1_RT_HEADER_LENGTH);
563
564                 s->rstate=SSL_ST_READ_BODY;
565
566                 p=s->packet;
567
568                 /* Pull apart the header into the DTLS1_RECORD */
569                 rr->type= *(p++);
570                 ssl_major= *(p++);
571                 ssl_minor= *(p++);
572                 version=(ssl_major<<8)|ssl_minor;
573
574                 /* sequence number is 64 bits, with top 2 bytes = epoch */ 
575                 n2s(p,rr->epoch);
576
577                 memcpy(&(s->s3->read_sequence[2]), p, 6);
578                 p+=6;
579
580                 n2s(p,rr->length);
581
582                 /* Lets check version */
583                 if (!s->first_packet)
584                         {
585                         if (version != s->version)
586                                 {
587                                 SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
588                                 /* Send back error using their
589                                  * version number :-) */
590                                 s->version=version;
591                                 al=SSL_AD_PROTOCOL_VERSION;
592                                 goto f_err;
593                                 }
594                         }
595
596                 if ((version & 0xff00) != (DTLS1_VERSION & 0xff00))
597                         {
598                         SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
599                         goto err;
600                         }
601
602                 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
603                         {
604                         al=SSL_AD_RECORD_OVERFLOW;
605                         SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_PACKET_LENGTH_TOO_LONG);
606                         goto f_err;
607                         }
608
609                 /* now s->rstate == SSL_ST_READ_BODY */
610                 }
611
612         /* s->rstate == SSL_ST_READ_BODY, get and decode the data */
613
614         if (rr->length > s->packet_length-DTLS1_RT_HEADER_LENGTH)
615                 {
616                 /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
617                 i=rr->length;
618                 n=ssl3_read_n(s,i,i,1);
619                 if (n <= 0) return(n); /* error or non-blocking io */
620
621                 /* this packet contained a partial record, dump it */
622                 if ( n != i)
623                         {
624                         s->packet_length = 0;
625                         goto again;
626                         }
627
628                 /* now n == rr->length,
629                  * and s->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length */
630                 }
631         s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
632
633         /* match epochs.  NULL means the packet is dropped on the floor */
634         bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
635         if ( bitmap == NULL)
636                 {
637                 s->packet_length = 0;  /* dump this record */
638                 goto again;   /* get another record */
639                 }
640
641         /* check whether this is a repeat, or aged record */
642         if ( ! dtls1_record_replay_check(s, bitmap))
643                 {
644                 rr->length = 0;
645                 s->packet_length=0; /* dump this record */
646                 goto again;     /* get another record */
647                 }
648
649         /* just read a 0 length packet */
650         if (rr->length == 0) goto again;
651
652         /* If this record is from the next epoch (either HM or ALERT),
653          * buffer it since it cannot be processed at this time. Records
654          * from the next epoch are marked as received even though they
655          * are not processed, so as to prevent any potential resource
656          * DoS attack */
657         if (is_next_epoch)
658                 {
659                 dtls1_record_bitmap_update(s, bitmap);
660                 dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num);
661                 s->packet_length = 0;
662                 goto again;
663                 }
664
665         if ( ! dtls1_process_record(s))
666                 return(0);
667
668         dtls1_clear_timeouts(s);  /* done waiting */
669         return(1);
670
671 f_err:
672         ssl3_send_alert(s,SSL3_AL_FATAL,al);
673 err:
674         return(0);
675         }
676
677 /* Return up to 'len' payload bytes received in 'type' records.
678  * 'type' is one of the following:
679  *
680  *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
681  *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
682  *   -  0 (during a shutdown, no data has to be returned)
683  *
684  * If we don't have stored data to work from, read a SSL/TLS record first
685  * (possibly multiple records if we still don't have anything to return).
686  *
687  * This function must handle any surprises the peer may have for us, such as
688  * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
689  * a surprise, but handled as if it were), or renegotiation requests.
690  * Also if record payloads contain fragments too small to process, we store
691  * them until there is enough for the respective protocol (the record protocol
692  * may use arbitrary fragmentation and even interleaving):
693  *     Change cipher spec protocol
694  *             just 1 byte needed, no need for keeping anything stored
695  *     Alert protocol
696  *             2 bytes needed (AlertLevel, AlertDescription)
697  *     Handshake protocol
698  *             4 bytes needed (HandshakeType, uint24 length) -- we just have
699  *             to detect unexpected Client Hello and Hello Request messages
700  *             here, anything else is handled by higher layers
701  *     Application data protocol
702  *             none of our business
703  */
704 int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
705         {
706         int al,i,j,ret;
707         unsigned int n;
708         SSL3_RECORD *rr;
709         void (*cb)(const SSL *ssl,int type2,int val)=NULL;
710
711         if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
712                 if (!ssl3_setup_buffers(s))
713                         return(-1);
714
715     /* XXX: check what the second '&& type' is about */
716         if ((type && (type != SSL3_RT_APPLICATION_DATA) && 
717                 (type != SSL3_RT_HANDSHAKE) && type) ||
718             (peek && (type != SSL3_RT_APPLICATION_DATA)))
719                 {
720                 SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
721                 return -1;
722                 }
723
724         /* check whether there's a handshake message (client hello?) waiting */
725         if ( (ret = have_handshake_fragment(s, type, buf, len, peek)))
726                 return ret;
727
728         /* Now s->d1->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
729
730         if (!s->in_handshake && SSL_in_init(s))
731                 {
732                 /* type == SSL3_RT_APPLICATION_DATA */
733                 i=s->handshake_func(s);
734                 if (i < 0) return(i);
735                 if (i == 0)
736                         {
737                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
738                         return(-1);
739                         }
740                 }
741
742 start:
743         s->rwstate=SSL_NOTHING;
744
745         /* s->s3->rrec.type         - is the type of record
746          * s->s3->rrec.data,    - data
747          * s->s3->rrec.off,     - offset into 'data' for next read
748          * s->s3->rrec.length,  - number of bytes. */
749         rr = &(s->s3->rrec);
750
751         /* get new packet if necessary */
752         if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
753                 {
754                 ret=dtls1_get_record(s);
755                 if (ret <= 0) 
756                         {
757                         ret = dtls1_read_failed(s, ret);
758                         /* anything other than a timeout is an error */
759                         if (ret <= 0)  
760                                 return(ret);
761                         else
762                                 goto start;
763                         }
764                 }
765
766         /* we now have a packet which can be read and processed */
767
768         if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
769                                        * reset by ssl3_get_finished */
770                 && (rr->type != SSL3_RT_HANDSHAKE))
771                 {
772                 al=SSL_AD_UNEXPECTED_MESSAGE;
773                 SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
774                 goto err;
775                 }
776
777         /* If the other end has shut down, throw anything we read away
778          * (even in 'peek' mode) */
779         if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
780                 {
781                 rr->length=0;
782                 s->rwstate=SSL_NOTHING;
783                 return(0);
784                 }
785
786
787         if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
788                 {
789                 /* make sure that we are not getting application data when we
790                  * are doing a handshake for the first time */
791                 if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
792                         (s->enc_read_ctx == NULL))
793                         {
794                         al=SSL_AD_UNEXPECTED_MESSAGE;
795                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
796                         goto f_err;
797                         }
798
799                 if (len <= 0) return(len);
800
801                 if ((unsigned int)len > rr->length)
802                         n = rr->length;
803                 else
804                         n = (unsigned int)len;
805
806                 memcpy(buf,&(rr->data[rr->off]),n);
807                 if (!peek)
808                         {
809                         rr->length-=n;
810                         rr->off+=n;
811                         if (rr->length == 0)
812                                 {
813                                 s->rstate=SSL_ST_READ_HEADER;
814                                 rr->off=0;
815                                 }
816                         }
817                 return(n);
818                 }
819
820
821         /* If we get here, then type != rr->type; if we have a handshake
822          * message, then it was unexpected (Hello Request or Client Hello). */
823
824         /* In case of record types for which we have 'fragment' storage,
825          * fill that so that we can process the data at a fixed place.
826          */
827                 {
828                 unsigned int k, dest_maxlen = 0;
829                 unsigned char *dest = NULL;
830                 unsigned int *dest_len = NULL;
831
832                 if (rr->type == SSL3_RT_HANDSHAKE)
833                         {
834                         dest_maxlen = sizeof s->d1->handshake_fragment;
835                         dest = s->d1->handshake_fragment;
836                         dest_len = &s->d1->handshake_fragment_len;
837                         }
838                 else if (rr->type == SSL3_RT_ALERT)
839                         {
840                         dest_maxlen = sizeof(s->d1->alert_fragment);
841                         dest = s->d1->alert_fragment;
842                         dest_len = &s->d1->alert_fragment_len;
843                         }
844                 /* else it's a CCS message, or it's wrong */
845                 else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
846                         {
847                           /* Not certain if this is the right error handling */
848                           al=SSL_AD_UNEXPECTED_MESSAGE;
849                           SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
850                           goto f_err;
851                         }
852
853
854                 if (dest_maxlen > 0)
855                         {
856             /* XDTLS:  In a pathalogical case, the Client Hello
857              *  may be fragmented--don't always expect dest_maxlen bytes */
858                         if ( rr->length < dest_maxlen)
859                                 {
860 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
861                                 /*
862                                  * for normal alerts rr->length is 2, while
863                                  * dest_maxlen is 7 if we were to handle this
864                                  * non-existing alert...
865                                  */
866                                 FIX ME
867 #endif
868                                 s->rstate=SSL_ST_READ_HEADER;
869                                 rr->length = 0;
870                                 goto start;
871                                 }
872
873                         /* now move 'n' bytes: */
874                         for ( k = 0; k < dest_maxlen; k++)
875                                 {
876                                 dest[k] = rr->data[rr->off++];
877                                 rr->length--;
878                                 }
879                         *dest_len = dest_maxlen;
880                         }
881                 }
882
883         /* s->d1->handshake_fragment_len == 12  iff  rr->type == SSL3_RT_HANDSHAKE;
884          * s->d1->alert_fragment_len == 7      iff  rr->type == SSL3_RT_ALERT.
885          * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
886
887         /* If we are a client, check for an incoming 'Hello Request': */
888         if ((!s->server) &&
889                 (s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
890                 (s->d1->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
891                 (s->session != NULL) && (s->session->cipher != NULL))
892                 {
893                 s->d1->handshake_fragment_len = 0;
894
895                 if ((s->d1->handshake_fragment[1] != 0) ||
896                         (s->d1->handshake_fragment[2] != 0) ||
897                         (s->d1->handshake_fragment[3] != 0))
898                         {
899                         al=SSL_AD_DECODE_ERROR;
900                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
901                         goto err;
902                         }
903
904                 /* no need to check sequence number on HELLO REQUEST messages */
905
906                 if (s->msg_callback)
907                         s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 
908                                 s->d1->handshake_fragment, 4, s, s->msg_callback_arg);
909
910                 if (SSL_is_init_finished(s) &&
911                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
912                         !s->s3->renegotiate)
913                         {
914                         ssl3_renegotiate(s);
915                         if (ssl3_renegotiate_check(s))
916                                 {
917                                 i=s->handshake_func(s);
918                                 if (i < 0) return(i);
919                                 if (i == 0)
920                                         {
921                                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
922                                         return(-1);
923                                         }
924
925                                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
926                                         {
927                                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
928                                                 {
929                                                 BIO *bio;
930                                                 /* In the case where we try to read application data,
931                                                  * but we trigger an SSL handshake, we return -1 with
932                                                  * the retry option set.  Otherwise renegotiation may
933                                                  * cause nasty problems in the blocking world */
934                                                 s->rwstate=SSL_READING;
935                                                 bio=SSL_get_rbio(s);
936                                                 BIO_clear_retry_flags(bio);
937                                                 BIO_set_retry_read(bio);
938                                                 return(-1);
939                                                 }
940                                         }
941                                 }
942                         }
943                 /* we either finished a handshake or ignored the request,
944                  * now try again to obtain the (application) data we were asked for */
945                 goto start;
946                 }
947
948         if (s->d1->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH)
949                 {
950                 int alert_level = s->d1->alert_fragment[0];
951                 int alert_descr = s->d1->alert_fragment[1];
952
953                 s->d1->alert_fragment_len = 0;
954
955                 if (s->msg_callback)
956                         s->msg_callback(0, s->version, SSL3_RT_ALERT, 
957                                 s->d1->alert_fragment, 2, s, s->msg_callback_arg);
958
959                 if (s->info_callback != NULL)
960                         cb=s->info_callback;
961                 else if (s->ctx->info_callback != NULL)
962                         cb=s->ctx->info_callback;
963
964                 if (cb != NULL)
965                         {
966                         j = (alert_level << 8) | alert_descr;
967                         cb(s, SSL_CB_READ_ALERT, j);
968                         }
969
970                 if (alert_level == 1) /* warning */
971                         {
972                         s->s3->warn_alert = alert_descr;
973                         if (alert_descr == SSL_AD_CLOSE_NOTIFY)
974                                 {
975                                 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
976                                 return(0);
977                                 }
978 #if 0
979             /* XXX: this is a possible improvement in the future */
980                         /* now check if it's a missing record */
981                         if (alert_descr == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
982                                 {
983                                 unsigned short seq;
984                                 unsigned int frag_off;
985                                 unsigned char *p = &(s->d1->alert_fragment[2]);
986
987                                 n2s(p, seq);
988                                 n2l3(p, frag_off);
989
990                                 dtls1_retransmit_message(s, seq, frag_off, &found);
991                                 if ( ! found  && SSL_in_init(s))
992                                         {
993                                         /* fprintf( stderr,"in init = %d\n", SSL_in_init(s)); */
994                                         /* requested a message not yet sent, 
995                                            send an alert ourselves */
996                                         ssl3_send_alert(s,SSL3_AL_WARNING,
997                                                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
998                                         }
999                                 }
1000 #endif
1001                         }
1002                 else if (alert_level == 2) /* fatal */
1003                         {
1004                         char tmp[16];
1005
1006                         s->rwstate=SSL_NOTHING;
1007                         s->s3->fatal_alert = alert_descr;
1008                         SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
1009                         BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
1010                         ERR_add_error_data(2,"SSL alert number ",tmp);
1011                         s->shutdown|=SSL_RECEIVED_SHUTDOWN;
1012                         SSL_CTX_remove_session(s->ctx,s->session);
1013                         return(0);
1014                         }
1015                 else
1016                         {
1017                         al=SSL_AD_ILLEGAL_PARAMETER;
1018                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
1019                         goto f_err;
1020                         }
1021
1022                 goto start;
1023                 }
1024
1025         if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
1026                 {
1027                 s->rwstate=SSL_NOTHING;
1028                 rr->length=0;
1029                 return(0);
1030                 }
1031
1032         if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1033                 {
1034                 struct ccs_header_st ccs_hdr;
1035
1036                 dtls1_get_ccs_header(rr->data, &ccs_hdr);
1037
1038                 /* 'Change Cipher Spec' is just a single byte, so we know
1039                  * exactly what the record payload has to look like */
1040                 /* XDTLS: check that epoch is consistent */
1041                 if (    (rr->length != DTLS1_CCS_HEADER_LENGTH) || 
1042                         (rr->off != 0) || (rr->data[0] != SSL3_MT_CCS))
1043                         {
1044                         i=SSL_AD_ILLEGAL_PARAMETER;
1045                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
1046                         goto err;
1047                         }
1048
1049                 rr->length=0;
1050
1051                 if (s->msg_callback)
1052                         s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, 
1053                                 rr->data, 1, s, s->msg_callback_arg);
1054
1055                 s->s3->change_cipher_spec=1;
1056                 if (!ssl3_do_change_cipher_spec(s))
1057                         goto err;
1058
1059                 /* do this whenever CCS is processed */
1060                 dtls1_reset_seq_numbers(s, SSL3_CC_READ);
1061
1062                 goto start;
1063                 }
1064
1065         /* Unexpected handshake message (Client Hello, or protocol violation) */
1066         if ((s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) && 
1067                 !s->in_handshake)
1068                 {
1069                 struct hm_header_st msg_hdr;
1070                 
1071                 /* this may just be a stale retransmit */
1072                 dtls1_get_message_header(rr->data, &msg_hdr);
1073                 if( rr->epoch != s->d1->r_epoch)
1074                         {
1075                         rr->length = 0;
1076                         goto start;
1077                         }
1078
1079                 if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
1080                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
1081                         {
1082 #if 0 /* worked only because C operator preferences are not as expected (and
1083        * because this is not really needed for clients except for detecting
1084        * protocol violations): */
1085                         s->state=SSL_ST_BEFORE|(s->server)
1086                                 ?SSL_ST_ACCEPT
1087                                 :SSL_ST_CONNECT;
1088 #else
1089                         s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
1090 #endif
1091                         s->new_session=1;
1092                         }
1093                 i=s->handshake_func(s);
1094                 if (i < 0) return(i);
1095                 if (i == 0)
1096                         {
1097                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1098                         return(-1);
1099                         }
1100
1101                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
1102                         {
1103                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
1104                                 {
1105                                 BIO *bio;
1106                                 /* In the case where we try to read application data,
1107                                  * but we trigger an SSL handshake, we return -1 with
1108                                  * the retry option set.  Otherwise renegotiation may
1109                                  * cause nasty problems in the blocking world */
1110                                 s->rwstate=SSL_READING;
1111                                 bio=SSL_get_rbio(s);
1112                                 BIO_clear_retry_flags(bio);
1113                                 BIO_set_retry_read(bio);
1114                                 return(-1);
1115                                 }
1116                         }
1117                 goto start;
1118                 }
1119
1120         switch (rr->type)
1121                 {
1122         default:
1123 #ifndef OPENSSL_NO_TLS
1124                 /* TLS just ignores unknown message types */
1125                 if (s->version == TLS1_VERSION)
1126                         {
1127                         rr->length = 0;
1128                         goto start;
1129                         }
1130 #endif
1131                 al=SSL_AD_UNEXPECTED_MESSAGE;
1132                 SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1133                 goto f_err;
1134         case SSL3_RT_CHANGE_CIPHER_SPEC:
1135         case SSL3_RT_ALERT:
1136         case SSL3_RT_HANDSHAKE:
1137                 /* we already handled all of these, with the possible exception
1138                  * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
1139                  * should not happen when type != rr->type */
1140                 al=SSL_AD_UNEXPECTED_MESSAGE;
1141                 SSLerr(SSL_F_DTLS1_READ_BYTES,ERR_R_INTERNAL_ERROR);
1142                 goto f_err;
1143         case SSL3_RT_APPLICATION_DATA:
1144                 /* At this point, we were expecting handshake data,
1145                  * but have application data.  If the library was
1146                  * running inside ssl3_read() (i.e. in_read_app_data
1147                  * is set) and it makes sense to read application data
1148                  * at this point (session renegotiation not yet started),
1149                  * we will indulge it.
1150                  */
1151                 if (s->s3->in_read_app_data &&
1152                         (s->s3->total_renegotiations != 0) &&
1153                         ((
1154                                 (s->state & SSL_ST_CONNECT) &&
1155                                 (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
1156                                 (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
1157                                 ) || (
1158                                         (s->state & SSL_ST_ACCEPT) &&
1159                                         (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
1160                                         (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
1161                                         )
1162                                 ))
1163                         {
1164                         s->s3->in_read_app_data=2;
1165                         return(-1);
1166                         }
1167                 else
1168                         {
1169                         al=SSL_AD_UNEXPECTED_MESSAGE;
1170                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1171                         goto f_err;
1172                         }
1173                 }
1174         /* not reached */
1175
1176 f_err:
1177         ssl3_send_alert(s,SSL3_AL_FATAL,al);
1178 err:
1179         return(-1);
1180         }
1181
1182 int
1183 dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
1184         {
1185         unsigned int n,tot;
1186         int i;
1187
1188         if (SSL_in_init(s) && !s->in_handshake)
1189                 {
1190                 i=s->handshake_func(s);
1191                 if (i < 0) return(i);
1192                 if (i == 0)
1193                         {
1194                         SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1195                         return -1;
1196                         }
1197                 }
1198
1199         tot = s->s3->wnum;
1200         n = len - tot;
1201
1202         while( n)
1203                 {
1204                 /* dtls1_write_bytes sends one record at a time, sized according to 
1205                  * the currently known MTU */
1206                 i = dtls1_write_bytes(s, type, buf_, len);
1207                 if (i <= 0) return i;
1208                 
1209                 if ((i == (int)n) ||
1210                         (type == SSL3_RT_APPLICATION_DATA &&
1211                                 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
1212                         {
1213                         /* next chunk of data should get another prepended empty fragment
1214                          * in ciphersuites with known-IV weakness: */
1215                         s->s3->empty_fragment_done = 0;
1216                         return tot+i;
1217                         }
1218
1219                 tot += i;
1220                 n-=i;
1221                 }
1222
1223         return tot;
1224         }
1225
1226
1227         /* this only happens when a client hello is received and a handshake 
1228          * is started. */
1229 static int
1230 have_handshake_fragment(SSL *s, int type, unsigned char *buf, 
1231         int len, int peek)
1232         {
1233         
1234         if ((type == SSL3_RT_HANDSHAKE) && (s->d1->handshake_fragment_len > 0))
1235                 /* (partially) satisfy request from storage */
1236                 {
1237                 unsigned char *src = s->d1->handshake_fragment;
1238                 unsigned char *dst = buf;
1239                 unsigned int k,n;
1240                 
1241                 /* peek == 0 */
1242                 n = 0;
1243                 while ((len > 0) && (s->d1->handshake_fragment_len > 0))
1244                         {
1245                         *dst++ = *src++;
1246                         len--; s->d1->handshake_fragment_len--;
1247                         n++;
1248                         }
1249                 /* move any remaining fragment bytes: */
1250                 for (k = 0; k < s->d1->handshake_fragment_len; k++)
1251                         s->d1->handshake_fragment[k] = *src++;
1252                 return n;
1253                 }
1254         
1255         return 0;
1256         }
1257
1258
1259
1260
1261 /* Call this to write data in records of type 'type'
1262  * It will return <= 0 if not all data has been sent or non-blocking IO.
1263  */
1264 int dtls1_write_bytes(SSL *s, int type, const void *buf_, int len)
1265         {
1266         const unsigned char *buf=buf_;
1267         unsigned int tot,n,nw;
1268         int i;
1269         unsigned int mtu;
1270
1271         s->rwstate=SSL_NOTHING;
1272         tot=s->s3->wnum;
1273
1274         n=(len-tot);
1275
1276         /* handshake layer figures out MTU for itself, but data records
1277          * are also sent through this interface, so need to figure out MTU */
1278 #if 0
1279         mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_MTU, 0, NULL);
1280         mtu += DTLS1_HM_HEADER_LENGTH;  /* HM already inserted */
1281 #endif
1282         mtu = s->d1->mtu;
1283
1284         if (mtu > SSL3_RT_MAX_PLAIN_LENGTH)
1285                 mtu = SSL3_RT_MAX_PLAIN_LENGTH;
1286
1287         if (n > mtu)
1288                 nw=mtu;
1289         else
1290                 nw=n;
1291         
1292         i=do_dtls1_write(s, type, &(buf[tot]), nw, 0);
1293         if (i <= 0)
1294                 {
1295                 s->s3->wnum=tot;
1296                 return i;
1297                 }
1298
1299         if ( (int)s->s3->wnum + i == len)
1300                 s->s3->wnum = 0;
1301         else 
1302                 s->s3->wnum += i;
1303
1304         return i;
1305         }
1306
1307 int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len, int create_empty_fragment)
1308         {
1309         unsigned char *p,*pseq;
1310         int i,mac_size,clear=0;
1311         int prefix_len = 0;
1312         SSL3_RECORD *wr;
1313         SSL3_BUFFER *wb;
1314         SSL_SESSION *sess;
1315         int bs;
1316
1317         /* first check if there is a SSL3_BUFFER still being written
1318          * out.  This will happen with non blocking IO */
1319         if (s->s3->wbuf.left != 0)
1320                 {
1321                 OPENSSL_assert(0); /* XDTLS:  want to see if we ever get here */
1322                 return(ssl3_write_pending(s,type,buf,len));
1323                 }
1324
1325         /* If we have an alert to send, lets send it */
1326         if (s->s3->alert_dispatch)
1327                 {
1328                 i=s->method->ssl_dispatch_alert(s);
1329                 if (i <= 0)
1330                         return(i);
1331                 /* if it went, fall through and send more stuff */
1332                 }
1333
1334         if (len == 0 && !create_empty_fragment)
1335                 return 0;
1336
1337         wr= &(s->s3->wrec);
1338         wb= &(s->s3->wbuf);
1339         sess=s->session;
1340
1341         if (    (sess == NULL) ||
1342                 (s->enc_write_ctx == NULL) ||
1343                 (EVP_MD_CTX_md(s->write_hash) == NULL))
1344                 clear=1;
1345
1346         if (clear)
1347                 mac_size=0;
1348         else
1349                 mac_size=EVP_MD_CTX_size(s->write_hash);
1350
1351         /* DTLS implements explicit IV, so no need for empty fragments */
1352 #if 0
1353         /* 'create_empty_fragment' is true only when this function calls itself */
1354         if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done
1355                 && SSL_version(s) != DTLS1_VERSION)
1356                 {
1357                 /* countermeasure against known-IV weakness in CBC ciphersuites
1358                  * (see http://www.openssl.org/~bodo/tls-cbc.txt) 
1359                  */
1360
1361                 if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
1362                         {
1363                         /* recursive function call with 'create_empty_fragment' set;
1364                          * this prepares and buffers the data for an empty fragment
1365                          * (these 'prefix_len' bytes are sent out later
1366                          * together with the actual payload) */
1367                         prefix_len = s->method->do_ssl_write(s, type, buf, 0, 1);
1368                         if (prefix_len <= 0)
1369                                 goto err;
1370
1371                         if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
1372                                 {
1373                                 /* insufficient space */
1374                                 SSLerr(SSL_F_DO_DTLS1_WRITE, ERR_R_INTERNAL_ERROR);
1375                                 goto err;
1376                                 }
1377                         }
1378                 
1379                 s->s3->empty_fragment_done = 1;
1380                 }
1381 #endif
1382
1383         p = wb->buf + prefix_len;
1384
1385         /* write the header */
1386
1387         *(p++)=type&0xff;
1388         wr->type=type;
1389
1390         *(p++)=(s->version>>8);
1391         *(p++)=s->version&0xff;
1392
1393         /* field where we are to write out packet epoch, seq num and len */
1394         pseq=p; 
1395         p+=10;
1396
1397         /* lets setup the record stuff. */
1398
1399         /* Make space for the explicit IV in case of CBC.
1400          * (this is a bit of a boundary violation, but what the heck).
1401          */
1402         if ( s->enc_write_ctx && 
1403                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher ) & EVP_CIPH_CBC_MODE))
1404                 bs = EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
1405         else
1406                 bs = 0;
1407
1408         wr->data=p + bs;  /* make room for IV in case of CBC */
1409         wr->length=(int)len;
1410         wr->input=(unsigned char *)buf;
1411
1412         /* we now 'read' from wr->input, wr->length bytes into
1413          * wr->data */
1414
1415         /* first we compress */
1416         if (s->compress != NULL)
1417                 {
1418                 if (!ssl3_do_compress(s))
1419                         {
1420                         SSLerr(SSL_F_DO_DTLS1_WRITE,SSL_R_COMPRESSION_FAILURE);
1421                         goto err;
1422                         }
1423                 }
1424         else
1425                 {
1426                 memcpy(wr->data,wr->input,wr->length);
1427                 wr->input=wr->data;
1428                 }
1429
1430         /* we should still have the output to wr->data and the input
1431          * from wr->input.  Length should be wr->length.
1432          * wr->data still points in the wb->buf */
1433
1434         if (mac_size != 0)
1435                 {
1436                 s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1);
1437                 wr->length+=mac_size;
1438                 }
1439
1440         /* this is true regardless of mac size */
1441         wr->input=p;
1442         wr->data=p;
1443
1444
1445         /* ssl3_enc can only have an error on read */
1446         if (bs) /* bs != 0 in case of CBC */
1447                 {
1448                 RAND_pseudo_bytes(p,bs);
1449                 /* master IV and last CBC residue stand for
1450                  * the rest of randomness */
1451                 wr->length += bs;
1452                 }
1453
1454         s->method->ssl3_enc->enc(s,1);
1455
1456         /* record length after mac and block padding */
1457 /*      if (type == SSL3_RT_APPLICATION_DATA ||
1458         (type == SSL3_RT_ALERT && ! SSL_in_init(s))) */
1459         
1460         /* there's only one epoch between handshake and app data */
1461         
1462         s2n(s->d1->w_epoch, pseq);
1463
1464         /* XDTLS: ?? */
1465 /*      else
1466         s2n(s->d1->handshake_epoch, pseq); */
1467
1468         memcpy(pseq, &(s->s3->write_sequence[2]), 6);
1469         pseq+=6;
1470         s2n(wr->length,pseq);
1471
1472         /* we should now have
1473          * wr->data pointing to the encrypted data, which is
1474          * wr->length long */
1475         wr->type=type; /* not needed but helps for debugging */
1476         wr->length+=DTLS1_RT_HEADER_LENGTH;
1477
1478 #if 0  /* this is now done at the message layer */
1479         /* buffer the record, making it easy to handle retransmits */
1480         if ( type == SSL3_RT_HANDSHAKE || type == SSL3_RT_CHANGE_CIPHER_SPEC)
1481                 dtls1_buffer_record(s, wr->data, wr->length, 
1482                         *((PQ_64BIT *)&(s->s3->write_sequence[0])));
1483 #endif
1484
1485         ssl3_record_sequence_update(&(s->s3->write_sequence[0]));
1486
1487         if (create_empty_fragment)
1488                 {
1489                 /* we are in a recursive call;
1490                  * just return the length, don't write out anything here
1491                  */
1492                 return wr->length;
1493                 }
1494
1495         /* now let's set up wb */
1496         wb->left = prefix_len + wr->length;
1497         wb->offset = 0;
1498
1499         /* memorize arguments so that ssl3_write_pending can detect bad write retries later */
1500         s->s3->wpend_tot=len;
1501         s->s3->wpend_buf=buf;
1502         s->s3->wpend_type=type;
1503         s->s3->wpend_ret=len;
1504
1505         /* we now just need to write the buffer */
1506         return ssl3_write_pending(s,type,buf,len);
1507 err:
1508         return -1;
1509         }
1510
1511
1512
1513 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
1514         {
1515         int cmp;
1516         unsigned int shift;
1517         const unsigned char *seq = s->s3->read_sequence;
1518
1519         cmp = satsub64be(seq,bitmap->max_seq_num);
1520         if (cmp > 0)
1521                 {
1522                 memcpy (s->s3->rrec.seq_num,seq,8);
1523                 return 1; /* this record in new */
1524                 }
1525         shift = -cmp;
1526         if (shift >= sizeof(bitmap->map)*8)
1527                 return 0; /* stale, outside the window */
1528         else if (bitmap->map & (1UL<<shift))
1529                 return 0; /* record previously received */
1530
1531         memcpy (s->s3->rrec.seq_num,seq,8);
1532         return 1;
1533         }
1534
1535
1536 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
1537         {
1538         int cmp;
1539         unsigned int shift;
1540         const unsigned char *seq = s->s3->read_sequence;
1541
1542         cmp = satsub64be(seq,bitmap->max_seq_num);
1543         if (cmp > 0)
1544                 {
1545                 shift = cmp;
1546                 if (shift < sizeof(bitmap->map)*8)
1547                         bitmap->map <<= shift, bitmap->map |= 1UL;
1548                 else
1549                         bitmap->map = 1UL;
1550                 memcpy(bitmap->max_seq_num,seq,8);
1551                 }
1552         else    {
1553                 shift = -cmp;
1554                 if (shift < sizeof(bitmap->map)*8)
1555                         bitmap->map |= 1UL<<shift;
1556                 }
1557         }
1558
1559
1560 int dtls1_dispatch_alert(SSL *s)
1561         {
1562         int i,j;
1563         void (*cb)(const SSL *ssl,int type,int val)=NULL;
1564         unsigned char buf[DTLS1_AL_HEADER_LENGTH];
1565         unsigned char *ptr = &buf[0];
1566
1567         s->s3->alert_dispatch=0;
1568
1569         memset(buf, 0x00, sizeof(buf));
1570         *ptr++ = s->s3->send_alert[0];
1571         *ptr++ = s->s3->send_alert[1];
1572
1573 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1574         if (s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
1575                 {       
1576                 s2n(s->d1->handshake_read_seq, ptr);
1577 #if 0
1578                 if ( s->d1->r_msg_hdr.frag_off == 0)  /* waiting for a new msg */
1579
1580                 else
1581                         s2n(s->d1->r_msg_hdr.seq, ptr); /* partial msg read */
1582 #endif
1583
1584 #if 0
1585                 fprintf(stderr, "s->d1->handshake_read_seq = %d, s->d1->r_msg_hdr.seq = %d\n",s->d1->handshake_read_seq,s->d1->r_msg_hdr.seq);
1586 #endif
1587                 l2n3(s->d1->r_msg_hdr.frag_off, ptr);
1588                 }
1589 #endif
1590
1591         i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf), 0);
1592         if (i <= 0)
1593                 {
1594                 s->s3->alert_dispatch=1;
1595                 /* fprintf( stderr, "not done with alert\n" ); */
1596                 }
1597         else
1598                 {
1599                 if (s->s3->send_alert[0] == SSL3_AL_FATAL
1600 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1601                     || s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1602 #endif
1603                     )
1604                         (void)BIO_flush(s->wbio);
1605
1606                 if (s->msg_callback)
1607                         s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 
1608                                 2, s, s->msg_callback_arg);
1609
1610                 if (s->info_callback != NULL)
1611                         cb=s->info_callback;
1612                 else if (s->ctx->info_callback != NULL)
1613                         cb=s->ctx->info_callback;
1614
1615                 if (cb != NULL)
1616                         {
1617                         j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
1618                         cb(s,SSL_CB_WRITE_ALERT,j);
1619                         }
1620                 }
1621         return(i);
1622         }
1623
1624
1625 static DTLS1_BITMAP *
1626 dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, unsigned int *is_next_epoch)
1627     {
1628     
1629     *is_next_epoch = 0;
1630
1631     /* In current epoch, accept HM, CCS, DATA, & ALERT */
1632     if (rr->epoch == s->d1->r_epoch)
1633         return &s->d1->bitmap;
1634
1635     /* Only HM and ALERT messages can be from the next epoch */
1636     else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
1637         (rr->type == SSL3_RT_HANDSHAKE ||
1638             rr->type == SSL3_RT_ALERT))
1639         {
1640         *is_next_epoch = 1;
1641         return &s->d1->next_bitmap;
1642         }
1643
1644     return NULL;
1645     }
1646
1647 #if 0
1648 static int
1649 dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr, unsigned short *priority,
1650         unsigned long *offset)
1651         {
1652
1653         /* alerts are passed up immediately */
1654         if ( rr->type == SSL3_RT_APPLICATION_DATA ||
1655                 rr->type == SSL3_RT_ALERT)
1656                 return 0;
1657
1658         /* Only need to buffer if a handshake is underway.
1659          * (this implies that Hello Request and Client Hello are passed up
1660          * immediately) */
1661         if ( SSL_in_init(s))
1662                 {
1663                 unsigned char *data = rr->data;
1664                 /* need to extract the HM/CCS sequence number here */
1665                 if ( rr->type == SSL3_RT_HANDSHAKE ||
1666                         rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1667                         {
1668                         unsigned short seq_num;
1669                         struct hm_header_st msg_hdr;
1670                         struct ccs_header_st ccs_hdr;
1671
1672                         if ( rr->type == SSL3_RT_HANDSHAKE)
1673                                 {
1674                                 dtls1_get_message_header(data, &msg_hdr);
1675                                 seq_num = msg_hdr.seq;
1676                                 *offset = msg_hdr.frag_off;
1677                                 }
1678                         else
1679                                 {
1680                                 dtls1_get_ccs_header(data, &ccs_hdr);
1681                                 seq_num = ccs_hdr.seq;
1682                                 *offset = 0;
1683                                 }
1684                                 
1685                         /* this is either a record we're waiting for, or a
1686                          * retransmit of something we happened to previously 
1687                          * receive (higher layers will drop the repeat silently */
1688                         if ( seq_num < s->d1->handshake_read_seq)
1689                                 return 0;
1690                         if (rr->type == SSL3_RT_HANDSHAKE && 
1691                                 seq_num == s->d1->handshake_read_seq &&
1692                                 msg_hdr.frag_off < s->d1->r_msg_hdr.frag_off)
1693                                 return 0;
1694                         else if ( seq_num == s->d1->handshake_read_seq &&
1695                                 (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC ||
1696                                         msg_hdr.frag_off == s->d1->r_msg_hdr.frag_off))
1697                                 return 0;
1698                         else
1699                                 {
1700                                 *priority = seq_num;
1701                                 return 1;
1702                                 }
1703                         }
1704                 else /* unknown record type */
1705                         return 0;
1706                 }
1707
1708         return 0;
1709         }
1710 #endif
1711
1712 void
1713 dtls1_reset_seq_numbers(SSL *s, int rw)
1714         {
1715         unsigned char *seq;
1716         unsigned int seq_bytes = sizeof(s->s3->read_sequence);
1717
1718         if ( rw & SSL3_CC_READ)
1719                 {
1720                 seq = s->s3->read_sequence;
1721                 s->d1->r_epoch++;
1722                 memcpy(&(s->d1->bitmap), &(s->d1->next_bitmap), sizeof(DTLS1_BITMAP));
1723                 memset(&(s->d1->next_bitmap), 0x00, sizeof(DTLS1_BITMAP));
1724                 }
1725         else
1726                 {
1727                 seq = s->s3->write_sequence;
1728                 s->d1->w_epoch++;
1729                 }
1730
1731         memset(seq, 0x00, seq_bytes);
1732         }
1733
1734
1735 static void
1736 dtls1_clear_timeouts(SSL *s)
1737         {
1738         memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
1739         }