1/* ssl/s3_pkt.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58/* ====================================================================
59 * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 *    notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 *    notice, this list of conditions and the following disclaimer in
70 *    the documentation and/or other materials provided with the
71 *    distribution.
72 *
73 * 3. All advertising materials mentioning features or use of this
74 *    software must display the following acknowledgment:
75 *    "This product includes software developed by the OpenSSL Project
76 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77 *
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 *    endorse or promote products derived from this software without
80 *    prior written permission. For written permission, please contact
81 *    openssl-core@openssl.org.
82 *
83 * 5. Products derived from this software may not be called "OpenSSL"
84 *    nor may "OpenSSL" appear in their names without prior written
85 *    permission of the OpenSSL Project.
86 *
87 * 6. Redistributions of any form whatsoever must retain the following
88 *    acknowledgment:
89 *    "This product includes software developed by the OpenSSL Project
90 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91 *
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
105 *
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com).  This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
109 *
110 */
111
112#include <stdio.h>
113#include <errno.h>
114#define USE_SOCKETS
115#include "ssl_locl.h"
116#include <openssl/evp.h>
117#include <openssl/buffer.h>
118
119static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
120			 unsigned int len, int create_empty_fragment);
121static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
122			      unsigned int len);
123static int ssl3_get_record(SSL *s);
124static int do_compress(SSL *ssl);
125static int do_uncompress(SSL *ssl);
126static int do_change_cipher_spec(SSL *ssl);
127
128/* used only by ssl3_get_record */
129static int ssl3_read_n(SSL *s, int n, int max, int extend)
130	{
131	/* If extend == 0, obtain new n-byte packet; if extend == 1, increase
132	 * packet by another n bytes.
133	 * The packet will be in the sub-array of s->s3->rbuf.buf specified
134	 * by s->packet and s->packet_length.
135	 * (If s->read_ahead is set, 'max' bytes may be stored in rbuf
136	 * [plus s->packet_length bytes if extend == 1].)
137	 */
138	int i,off,newb;
139
140	if (!extend)
141		{
142		/* start with empty packet ... */
143		if (s->s3->rbuf.left == 0)
144			s->s3->rbuf.offset = 0;
145		s->packet = s->s3->rbuf.buf + s->s3->rbuf.offset;
146		s->packet_length = 0;
147		/* ... now we can act as if 'extend' was set */
148		}
149
150	/* if there is enough in the buffer from a previous read, take some */
151	if (s->s3->rbuf.left >= (int)n)
152		{
153		s->packet_length+=n;
154		s->s3->rbuf.left-=n;
155		s->s3->rbuf.offset+=n;
156		return(n);
157		}
158
159	/* else we need to read more data */
160	if (!s->read_ahead)
161		max=n;
162
163	{
164		/* avoid buffer overflow */
165		int max_max = s->s3->rbuf.len - s->packet_length;
166		if (max > max_max)
167			max = max_max;
168	}
169	if (n > max) /* does not happen */
170		{
171		SSLerr(SSL_F_SSL3_READ_N,ERR_R_INTERNAL_ERROR);
172		return -1;
173		}
174
175	off = s->packet_length;
176	newb = s->s3->rbuf.left;
177	/* Move any available bytes to front of buffer:
178	 * 'off' bytes already pointed to by 'packet',
179	 * 'newb' extra ones at the end */
180	if (s->packet != s->s3->rbuf.buf)
181		{
182		/*  off > 0 */
183		memmove(s->s3->rbuf.buf, s->packet, off+newb);
184		s->packet = s->s3->rbuf.buf;
185		}
186
187	while (newb < n)
188		{
189		/* Now we have off+newb bytes at the front of s->s3->rbuf.buf and need
190		 * to read in more until we have off+n (up to off+max if possible) */
191
192		clear_sys_error();
193		if (s->rbio != NULL)
194			{
195			s->rwstate=SSL_READING;
196			i=BIO_read(s->rbio,	&(s->s3->rbuf.buf[off+newb]), max-newb);
197			}
198		else
199			{
200			SSLerr(SSL_F_SSL3_READ_N,SSL_R_READ_BIO_NOT_SET);
201			i = -1;
202			}
203
204		if (i <= 0)
205			{
206			s->s3->rbuf.left = newb;
207			return(i);
208			}
209		newb+=i;
210		}
211
212	/* done reading, now the book-keeping */
213	s->s3->rbuf.offset = off + n;
214	s->s3->rbuf.left = newb - n;
215	s->packet_length += n;
216	s->rwstate=SSL_NOTHING;
217	return(n);
218	}
219
220/* Call this to get a new input record.
221 * It will return <= 0 if more data is needed, normally due to an error
222 * or non-blocking IO.
223 * When it finishes, one packet has been decoded and can be found in
224 * ssl->s3->rrec.type    - is the type of record
225 * ssl->s3->rrec.data, 	 - data
226 * ssl->s3->rrec.length, - number of bytes
227 */
228/* used only by ssl3_read_bytes */
229static int ssl3_get_record(SSL *s)
230	{
231	int ssl_major,ssl_minor,al;
232	int enc_err,n,i,ret= -1;
233	SSL3_RECORD *rr;
234	SSL_SESSION *sess;
235	unsigned char *p;
236	unsigned char md[EVP_MAX_MD_SIZE];
237	short version;
238	unsigned int mac_size;
239	int clear=0;
240	size_t extra;
241	int decryption_failed_or_bad_record_mac = 0;
242	unsigned char *mac = NULL;
243
244	rr= &(s->s3->rrec);
245	sess=s->session;
246
247	if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
248		extra=SSL3_RT_MAX_EXTRA;
249	else
250		extra=0;
251	if (extra != s->s3->rbuf.len - SSL3_RT_MAX_PACKET_SIZE)
252		{
253		/* actually likely an application error: SLS_OP_MICROSOFT_BIG_SSLV3_BUFFER
254		 * set after ssl3_setup_buffers() was done */
255		SSLerr(SSL_F_SSL3_GET_RECORD, ERR_R_INTERNAL_ERROR);
256		return -1;
257		}
258
259again:
260	/* check if we have the header */
261	if (	(s->rstate != SSL_ST_READ_BODY) ||
262		(s->packet_length < SSL3_RT_HEADER_LENGTH))
263		{
264		n=ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
265		if (n <= 0) return(n); /* error or non-blocking */
266		s->rstate=SSL_ST_READ_BODY;
267
268		p=s->packet;
269
270		/* Pull apart the header into the SSL3_RECORD */
271		rr->type= *(p++);
272		ssl_major= *(p++);
273		ssl_minor= *(p++);
274		version=(ssl_major<<8)|ssl_minor;
275		n2s(p,rr->length);
276
277		/* Lets check version */
278		if (s->first_packet)
279			{
280			s->first_packet=0;
281			}
282		else
283			{
284			if (version != s->version)
285				{
286				SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
287				/* Send back error using their
288				 * version number :-) */
289				s->version=version;
290				al=SSL_AD_PROTOCOL_VERSION;
291				goto f_err;
292				}
293			}
294
295		if ((version>>8) != SSL3_VERSION_MAJOR)
296			{
297			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
298			goto err;
299			}
300
301		if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
302			{
303			al=SSL_AD_RECORD_OVERFLOW;
304			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PACKET_LENGTH_TOO_LONG);
305			goto f_err;
306			}
307
308		/* now s->rstate == SSL_ST_READ_BODY */
309		}
310
311	/* s->rstate == SSL_ST_READ_BODY, get and decode the data */
312
313	if (rr->length > s->packet_length-SSL3_RT_HEADER_LENGTH)
314		{
315		/* now s->packet_length == SSL3_RT_HEADER_LENGTH */
316		i=rr->length;
317		n=ssl3_read_n(s,i,i,1);
318		if (n <= 0) return(n); /* error or non-blocking io */
319		/* now n == rr->length,
320		 * and s->packet_length == SSL3_RT_HEADER_LENGTH + rr->length */
321		}
322
323	s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
324
325	/* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
326	 * and we have that many bytes in s->packet
327	 */
328	rr->input= &(s->packet[SSL3_RT_HEADER_LENGTH]);
329
330	/* ok, we can now read from 's->packet' data into 'rr'
331	 * rr->input points at rr->length bytes, which
332	 * need to be copied into rr->data by either
333	 * the decryption or by the decompression
334	 * When the data is 'copied' into the rr->data buffer,
335	 * rr->input will be pointed at the new buffer */
336
337	/* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
338	 * rr->length bytes of encrypted compressed stuff. */
339
340	/* check is not needed I believe */
341	if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
342		{
343		al=SSL_AD_RECORD_OVERFLOW;
344		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
345		goto f_err;
346		}
347
348	/* decrypt in place in 'rr->input' */
349	rr->data=rr->input;
350
351	enc_err = s->method->ssl3_enc->enc(s,0);
352	if (enc_err <= 0)
353		{
354		if (enc_err == 0)
355			/* SSLerr() and ssl3_send_alert() have been called */
356			goto err;
357
358		/* Otherwise enc_err == -1, which indicates bad padding
359		 * (rec->length has not been changed in this case).
360		 * To minimize information leaked via timing, we will perform
361		 * the MAC computation anyway. */
362		decryption_failed_or_bad_record_mac = 1;
363		}
364
365#ifdef TLS_DEBUG
366printf("dec %d\n",rr->length);
367{ unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
368printf("\n");
369#endif
370
371	/* r->length is now the compressed data plus mac */
372	if (	(sess == NULL) ||
373		(s->enc_read_ctx == NULL) ||
374		(s->read_hash == NULL))
375		clear=1;
376
377	if (!clear)
378		{
379		mac_size=EVP_MD_size(s->read_hash);
380
381		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
382			{
383#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
384			al=SSL_AD_RECORD_OVERFLOW;
385			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
386			goto f_err;
387#else
388			decryption_failed_or_bad_record_mac = 1;
389#endif
390			}
391		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
392		if (rr->length >= mac_size)
393			{
394			rr->length -= mac_size;
395			mac = &rr->data[rr->length];
396			}
397		else
398			{
399			/* record (minus padding) is too short to contain a MAC */
400#if 0 /* OK only for stream ciphers */
401			al=SSL_AD_DECODE_ERROR;
402			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
403			goto f_err;
404#else
405			decryption_failed_or_bad_record_mac = 1;
406			rr->length = 0;
407#endif
408			}
409		i=s->method->ssl3_enc->mac(s,md,0);
410		if (mac == NULL || memcmp(md, mac, mac_size) != 0)
411			{
412			decryption_failed_or_bad_record_mac = 1;
413			}
414		}
415
416	if (decryption_failed_or_bad_record_mac)
417		{
418		/* A separate 'decryption_failed' alert was introduced with TLS 1.0,
419		 * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
420		 * failure is directly visible from the ciphertext anyway,
421		 * we should not reveal which kind of error occured -- this
422		 * might become visible to an attacker (e.g. via a logfile) */
423		al=SSL_AD_BAD_RECORD_MAC;
424		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
425		goto f_err;
426		}
427
428	/* r->length is now just compressed */
429	if (s->expand != NULL)
430		{
431		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra)
432			{
433			al=SSL_AD_RECORD_OVERFLOW;
434			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
435			goto f_err;
436			}
437		if (!do_uncompress(s))
438			{
439			al=SSL_AD_DECOMPRESSION_FAILURE;
440			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_DECOMPRESSION);
441			goto f_err;
442			}
443		}
444
445	if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra)
446		{
447		al=SSL_AD_RECORD_OVERFLOW;
448		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
449		goto f_err;
450		}
451
452	rr->off=0;
453	/* So at this point the following is true
454	 * ssl->s3->rrec.type 	is the type of record
455	 * ssl->s3->rrec.length	== number of bytes in record
456	 * ssl->s3->rrec.off	== offset to first valid byte
457	 * ssl->s3->rrec.data	== where to take bytes from, increment
458	 *			   after use :-).
459	 */
460
461	/* we have pulled in a full packet so zero things */
462	s->packet_length=0;
463
464	/* just read a 0 length packet */
465	if (rr->length == 0) goto again;
466
467	return(1);
468
469f_err:
470	ssl3_send_alert(s,SSL3_AL_FATAL,al);
471err:
472	return(ret);
473	}
474
475static int do_uncompress(SSL *ssl)
476	{
477	int i;
478	SSL3_RECORD *rr;
479
480	rr= &(ssl->s3->rrec);
481	i=COMP_expand_block(ssl->expand,rr->comp,
482		SSL3_RT_MAX_PLAIN_LENGTH,rr->data,(int)rr->length);
483	if (i < 0)
484		return(0);
485	else
486		rr->length=i;
487	rr->data=rr->comp;
488
489	return(1);
490	}
491
492static int do_compress(SSL *ssl)
493	{
494	int i;
495	SSL3_RECORD *wr;
496
497	wr= &(ssl->s3->wrec);
498	i=COMP_compress_block(ssl->compress,wr->data,
499		SSL3_RT_MAX_COMPRESSED_LENGTH,
500		wr->input,(int)wr->length);
501	if (i < 0)
502		return(0);
503	else
504		wr->length=i;
505
506	wr->input=wr->data;
507	return(1);
508	}
509
510/* Call this to write data in records of type 'type'
511 * It will return <= 0 if not all data has been sent or non-blocking IO.
512 */
513int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
514	{
515	const unsigned char *buf=buf_;
516	unsigned int tot,n,nw;
517	int i;
518
519	s->rwstate=SSL_NOTHING;
520	tot=s->s3->wnum;
521	s->s3->wnum=0;
522
523	if (SSL_in_init(s) && !s->in_handshake)
524		{
525		i=s->handshake_func(s);
526		if (i < 0) return(i);
527		if (i == 0)
528			{
529			SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
530			return -1;
531			}
532		}
533
534	n=(len-tot);
535	for (;;)
536		{
537		if (n > SSL3_RT_MAX_PLAIN_LENGTH)
538			nw=SSL3_RT_MAX_PLAIN_LENGTH;
539		else
540			nw=n;
541
542		i=do_ssl3_write(s, type, &(buf[tot]), nw, 0);
543		if (i <= 0)
544			{
545			s->s3->wnum=tot;
546			return i;
547			}
548
549		if ((i == (int)n) ||
550			(type == SSL3_RT_APPLICATION_DATA &&
551			 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
552			{
553			/* next chunk of data should get another prepended empty fragment
554			 * in ciphersuites with known-IV weakness: */
555			s->s3->empty_fragment_done = 0;
556
557			return tot+i;
558			}
559
560		n-=i;
561		tot+=i;
562		}
563	}
564
565static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
566			 unsigned int len, int create_empty_fragment)
567	{
568	unsigned char *p,*plen;
569	int i,mac_size,clear=0;
570	int prefix_len = 0;
571	SSL3_RECORD *wr;
572	SSL3_BUFFER *wb;
573	SSL_SESSION *sess;
574
575	/* first check if there is a SSL3_BUFFER still being written
576	 * out.  This will happen with non blocking IO */
577	if (s->s3->wbuf.left != 0)
578		return(ssl3_write_pending(s,type,buf,len));
579
580	/* If we have an alert to send, lets send it */
581	if (s->s3->alert_dispatch)
582		{
583		i=ssl3_dispatch_alert(s);
584		if (i <= 0)
585			return(i);
586		/* if it went, fall through and send more stuff */
587		}
588
589	if (len == 0 && !create_empty_fragment)
590		return 0;
591
592	wr= &(s->s3->wrec);
593	wb= &(s->s3->wbuf);
594	sess=s->session;
595
596	if (	(sess == NULL) ||
597		(s->enc_write_ctx == NULL) ||
598		(s->write_hash == NULL))
599		clear=1;
600
601	if (clear)
602		mac_size=0;
603	else
604		mac_size=EVP_MD_size(s->write_hash);
605
606	/* 'create_empty_fragment' is true only when this function calls itself */
607	if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done)
608		{
609		/* countermeasure against known-IV weakness in CBC ciphersuites
610		 * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
611
612		if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
613			{
614			/* recursive function call with 'create_empty_fragment' set;
615			 * this prepares and buffers the data for an empty fragment
616			 * (these 'prefix_len' bytes are sent out later
617			 * together with the actual payload) */
618			prefix_len = do_ssl3_write(s, type, buf, 0, 1);
619			if (prefix_len <= 0)
620				goto err;
621
622			if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
623				{
624				/* insufficient space */
625				SSLerr(SSL_F_DO_SSL3_WRITE, ERR_R_INTERNAL_ERROR);
626				goto err;
627				}
628			}
629
630		s->s3->empty_fragment_done = 1;
631		}
632
633	p = wb->buf + prefix_len;
634
635	/* write the header */
636
637	*(p++)=type&0xff;
638	wr->type=type;
639
640	*(p++)=(s->version>>8);
641	*(p++)=s->version&0xff;
642
643	/* field where we are to write out packet length */
644	plen=p;
645	p+=2;
646
647	/* lets setup the record stuff. */
648	wr->data=p;
649	wr->length=(int)len;
650	wr->input=(unsigned char *)buf;
651
652	/* we now 'read' from wr->input, wr->length bytes into
653	 * wr->data */
654
655	/* first we compress */
656	if (s->compress != NULL)
657		{
658		if (!do_compress(s))
659			{
660			SSLerr(SSL_F_DO_SSL3_WRITE,SSL_R_COMPRESSION_FAILURE);
661			goto err;
662			}
663		}
664	else
665		{
666		memcpy(wr->data,wr->input,wr->length);
667		wr->input=wr->data;
668		}
669
670	/* we should still have the output to wr->data and the input
671	 * from wr->input.  Length should be wr->length.
672	 * wr->data still points in the wb->buf */
673
674	if (mac_size != 0)
675		{
676		s->method->ssl3_enc->mac(s,&(p[wr->length]),1);
677		wr->length+=mac_size;
678		wr->input=p;
679		wr->data=p;
680		}
681
682	/* ssl3_enc can only have an error on read */
683	s->method->ssl3_enc->enc(s,1);
684
685	/* record length after mac and block padding */
686	s2n(wr->length,plen);
687
688	/* we should now have
689	 * wr->data pointing to the encrypted data, which is
690	 * wr->length long */
691	wr->type=type; /* not needed but helps for debugging */
692	wr->length+=SSL3_RT_HEADER_LENGTH;
693
694	if (create_empty_fragment)
695		{
696		/* we are in a recursive call;
697		 * just return the length, don't write out anything here
698		 */
699		return wr->length;
700		}
701
702	/* now let's set up wb */
703	wb->left = prefix_len + wr->length;
704	wb->offset = 0;
705
706	/* memorize arguments so that ssl3_write_pending can detect bad write retries later */
707	s->s3->wpend_tot=len;
708	s->s3->wpend_buf=buf;
709	s->s3->wpend_type=type;
710	s->s3->wpend_ret=len;
711
712	/* we now just need to write the buffer */
713	return ssl3_write_pending(s,type,buf,len);
714err:
715	return -1;
716	}
717
718/* if s->s3->wbuf.left != 0, we need to call this */
719static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
720			      unsigned int len)
721	{
722	int i;
723
724/* XXXX */
725	if ((s->s3->wpend_tot > (int)len)
726		|| ((s->s3->wpend_buf != buf) &&
727			!(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER))
728		|| (s->s3->wpend_type != type))
729		{
730		SSLerr(SSL_F_SSL3_WRITE_PENDING,SSL_R_BAD_WRITE_RETRY);
731		return(-1);
732		}
733
734	for (;;)
735		{
736		clear_sys_error();
737		if (s->wbio != NULL)
738			{
739			s->rwstate=SSL_WRITING;
740			i=BIO_write(s->wbio,
741				(char *)&(s->s3->wbuf.buf[s->s3->wbuf.offset]),
742				(unsigned int)s->s3->wbuf.left);
743			}
744		else
745			{
746			SSLerr(SSL_F_SSL3_WRITE_PENDING,SSL_R_BIO_NOT_SET);
747			i= -1;
748			}
749		if (i == s->s3->wbuf.left)
750			{
751			s->s3->wbuf.left=0;
752			s->rwstate=SSL_NOTHING;
753			return(s->s3->wpend_ret);
754			}
755		else if (i <= 0)
756			return(i);
757		s->s3->wbuf.offset+=i;
758		s->s3->wbuf.left-=i;
759		}
760	}
761
762/* Return up to 'len' payload bytes received in 'type' records.
763 * 'type' is one of the following:
764 *
765 *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
766 *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
767 *   -  0 (during a shutdown, no data has to be returned)
768 *
769 * If we don't have stored data to work from, read a SSL/TLS record first
770 * (possibly multiple records if we still don't have anything to return).
771 *
772 * This function must handle any surprises the peer may have for us, such as
773 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
774 * a surprise, but handled as if it were), or renegotiation requests.
775 * Also if record payloads contain fragments too small to process, we store
776 * them until there is enough for the respective protocol (the record protocol
777 * may use arbitrary fragmentation and even interleaving):
778 *     Change cipher spec protocol
779 *             just 1 byte needed, no need for keeping anything stored
780 *     Alert protocol
781 *             2 bytes needed (AlertLevel, AlertDescription)
782 *     Handshake protocol
783 *             4 bytes needed (HandshakeType, uint24 length) -- we just have
784 *             to detect unexpected Client Hello and Hello Request messages
785 *             here, anything else is handled by higher layers
786 *     Application data protocol
787 *             none of our business
788 */
789int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
790	{
791	int al,i,j,ret;
792	unsigned int n;
793	SSL3_RECORD *rr;
794	void (*cb)(const SSL *ssl,int type2,int val)=NULL;
795
796	if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
797		if (!ssl3_setup_buffers(s))
798			return(-1);
799
800	if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE) && type) ||
801	    (peek && (type != SSL3_RT_APPLICATION_DATA)))
802		{
803		SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
804		return -1;
805		}
806
807	if ((type == SSL3_RT_HANDSHAKE) && (s->s3->handshake_fragment_len > 0))
808		/* (partially) satisfy request from storage */
809		{
810		unsigned char *src = s->s3->handshake_fragment;
811		unsigned char *dst = buf;
812		unsigned int k;
813
814		/* peek == 0 */
815		n = 0;
816		while ((len > 0) && (s->s3->handshake_fragment_len > 0))
817			{
818			*dst++ = *src++;
819			len--; s->s3->handshake_fragment_len--;
820			n++;
821			}
822		/* move any remaining fragment bytes: */
823		for (k = 0; k < s->s3->handshake_fragment_len; k++)
824			s->s3->handshake_fragment[k] = *src++;
825		return n;
826	}
827
828	/* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
829
830	if (!s->in_handshake && SSL_in_init(s))
831		{
832		/* type == SSL3_RT_APPLICATION_DATA */
833		i=s->handshake_func(s);
834		if (i < 0) return(i);
835		if (i == 0)
836			{
837			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
838			return(-1);
839			}
840		}
841start:
842	s->rwstate=SSL_NOTHING;
843
844	/* s->s3->rrec.type	    - is the type of record
845	 * s->s3->rrec.data,    - data
846	 * s->s3->rrec.off,     - offset into 'data' for next read
847	 * s->s3->rrec.length,  - number of bytes. */
848	rr = &(s->s3->rrec);
849
850	/* get new packet if necessary */
851	if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
852		{
853		ret=ssl3_get_record(s);
854		if (ret <= 0) return(ret);
855		}
856
857	/* we now have a packet which can be read and processed */
858
859	if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
860	                               * reset by ssl3_get_finished */
861		&& (rr->type != SSL3_RT_HANDSHAKE))
862		{
863		al=SSL_AD_UNEXPECTED_MESSAGE;
864		SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
865		goto f_err;
866		}
867
868	/* If the other end has shut down, throw anything we read away
869	 * (even in 'peek' mode) */
870	if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
871		{
872		rr->length=0;
873		s->rwstate=SSL_NOTHING;
874		return(0);
875		}
876
877
878	if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
879		{
880		/* make sure that we are not getting application data when we
881		 * are doing a handshake for the first time */
882		if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
883			(s->enc_read_ctx == NULL))
884			{
885			al=SSL_AD_UNEXPECTED_MESSAGE;
886			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
887			goto f_err;
888			}
889
890		if (len <= 0) return(len);
891
892		if ((unsigned int)len > rr->length)
893			n = rr->length;
894		else
895			n = (unsigned int)len;
896
897		memcpy(buf,&(rr->data[rr->off]),n);
898		if (!peek)
899			{
900			rr->length-=n;
901			rr->off+=n;
902			if (rr->length == 0)
903				{
904				s->rstate=SSL_ST_READ_HEADER;
905				rr->off=0;
906				}
907			}
908		return(n);
909		}
910
911
912	/* If we get here, then type != rr->type; if we have a handshake
913	 * message, then it was unexpected (Hello Request or Client Hello). */
914
915	/* In case of record types for which we have 'fragment' storage,
916	 * fill that so that we can process the data at a fixed place.
917	 */
918		{
919		unsigned int dest_maxlen = 0;
920		unsigned char *dest = NULL;
921		unsigned int *dest_len = NULL;
922
923		if (rr->type == SSL3_RT_HANDSHAKE)
924			{
925			dest_maxlen = sizeof s->s3->handshake_fragment;
926			dest = s->s3->handshake_fragment;
927			dest_len = &s->s3->handshake_fragment_len;
928			}
929		else if (rr->type == SSL3_RT_ALERT)
930			{
931			dest_maxlen = sizeof s->s3->alert_fragment;
932			dest = s->s3->alert_fragment;
933			dest_len = &s->s3->alert_fragment_len;
934			}
935
936		if (dest_maxlen > 0)
937			{
938			n = dest_maxlen - *dest_len; /* available space in 'dest' */
939			if (rr->length < n)
940				n = rr->length; /* available bytes */
941
942			/* now move 'n' bytes: */
943			while (n-- > 0)
944				{
945				dest[(*dest_len)++] = rr->data[rr->off++];
946				rr->length--;
947				}
948
949			if (*dest_len < dest_maxlen)
950				goto start; /* fragment was too small */
951			}
952		}
953
954	/* s->s3->handshake_fragment_len == 4  iff  rr->type == SSL3_RT_HANDSHAKE;
955	 * s->s3->alert_fragment_len == 2      iff  rr->type == SSL3_RT_ALERT.
956	 * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
957
958	/* If we are a client, check for an incoming 'Hello Request': */
959	if ((!s->server) &&
960		(s->s3->handshake_fragment_len >= 4) &&
961		(s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
962		(s->session != NULL) && (s->session->cipher != NULL))
963		{
964		s->s3->handshake_fragment_len = 0;
965
966		if ((s->s3->handshake_fragment[1] != 0) ||
967			(s->s3->handshake_fragment[2] != 0) ||
968			(s->s3->handshake_fragment[3] != 0))
969			{
970			al=SSL_AD_DECODE_ERROR;
971			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
972			goto f_err;
973			}
974
975		if (s->msg_callback)
976			s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->s3->handshake_fragment, 4, s, s->msg_callback_arg);
977
978		if (SSL_is_init_finished(s) &&
979			!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
980			!s->s3->renegotiate)
981			{
982			ssl3_renegotiate(s);
983			if (ssl3_renegotiate_check(s))
984				{
985				i=s->handshake_func(s);
986				if (i < 0) return(i);
987				if (i == 0)
988					{
989					SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
990					return(-1);
991					}
992
993				if (!(s->mode & SSL_MODE_AUTO_RETRY))
994					{
995					if (s->s3->rbuf.left == 0) /* no read-ahead left? */
996						{
997						BIO *bio;
998						/* In the case where we try to read application data,
999						 * but we trigger an SSL handshake, we return -1 with
1000						 * the retry option set.  Otherwise renegotiation may
1001						 * cause nasty problems in the blocking world */
1002						s->rwstate=SSL_READING;
1003						bio=SSL_get_rbio(s);
1004						BIO_clear_retry_flags(bio);
1005						BIO_set_retry_read(bio);
1006						return(-1);
1007						}
1008					}
1009				}
1010			}
1011		/* we either finished a handshake or ignored the request,
1012		 * now try again to obtain the (application) data we were asked for */
1013		goto start;
1014		}
1015
1016	if (s->s3->alert_fragment_len >= 2)
1017		{
1018		int alert_level = s->s3->alert_fragment[0];
1019		int alert_descr = s->s3->alert_fragment[1];
1020
1021		s->s3->alert_fragment_len = 0;
1022
1023		if (s->msg_callback)
1024			s->msg_callback(0, s->version, SSL3_RT_ALERT, s->s3->alert_fragment, 2, s, s->msg_callback_arg);
1025
1026		if (s->info_callback != NULL)
1027			cb=s->info_callback;
1028		else if (s->ctx->info_callback != NULL)
1029			cb=s->ctx->info_callback;
1030
1031		if (cb != NULL)
1032			{
1033			j = (alert_level << 8) | alert_descr;
1034			cb(s, SSL_CB_READ_ALERT, j);
1035			}
1036
1037		if (alert_level == 1) /* warning */
1038			{
1039			s->s3->warn_alert = alert_descr;
1040			if (alert_descr == SSL_AD_CLOSE_NOTIFY)
1041				{
1042				s->shutdown |= SSL_RECEIVED_SHUTDOWN;
1043				return(0);
1044				}
1045			}
1046		else if (alert_level == 2) /* fatal */
1047			{
1048			char tmp[16];
1049
1050			s->rwstate=SSL_NOTHING;
1051			s->s3->fatal_alert = alert_descr;
1052			SSLerr(SSL_F_SSL3_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
1053			BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
1054			ERR_add_error_data(2,"SSL alert number ",tmp);
1055			s->shutdown|=SSL_RECEIVED_SHUTDOWN;
1056			SSL_CTX_remove_session(s->ctx,s->session);
1057			return(0);
1058			}
1059		else
1060			{
1061			al=SSL_AD_ILLEGAL_PARAMETER;
1062			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
1063			goto f_err;
1064			}
1065
1066		goto start;
1067		}
1068
1069	if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
1070		{
1071		s->rwstate=SSL_NOTHING;
1072		rr->length=0;
1073		return(0);
1074		}
1075
1076	if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1077		{
1078		/* 'Change Cipher Spec' is just a single byte, so we know
1079		 * exactly what the record payload has to look like */
1080		if (	(rr->length != 1) || (rr->off != 0) ||
1081			(rr->data[0] != SSL3_MT_CCS))
1082			{
1083			al=SSL_AD_ILLEGAL_PARAMETER;
1084			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
1085			goto f_err;
1086			}
1087
1088		/* Check we have a cipher to change to */
1089		if (s->s3->tmp.new_cipher == NULL)
1090			{
1091			al=SSL_AD_UNEXPECTED_MESSAGE;
1092			SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,SSL_R_CCS_RECEIVED_EARLY);
1093			goto f_err;
1094			}
1095
1096		rr->length=0;
1097
1098		if (s->msg_callback)
1099			s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s, s->msg_callback_arg);
1100
1101		s->s3->change_cipher_spec=1;
1102		if (!do_change_cipher_spec(s))
1103			goto err;
1104		else
1105			goto start;
1106		}
1107
1108	/* Unexpected handshake message (Client Hello, or protocol violation) */
1109	if ((s->s3->handshake_fragment_len >= 4) &&	!s->in_handshake)
1110		{
1111		if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
1112			!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
1113			{
1114#if 0 /* worked only because C operator preferences are not as expected (and
1115       * because this is not really needed for clients except for detecting
1116       * protocol violations): */
1117			s->state=SSL_ST_BEFORE|(s->server)
1118				?SSL_ST_ACCEPT
1119				:SSL_ST_CONNECT;
1120#else
1121			s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
1122#endif
1123			s->new_session=1;
1124			}
1125		i=s->handshake_func(s);
1126		if (i < 0) return(i);
1127		if (i == 0)
1128			{
1129			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1130			return(-1);
1131			}
1132
1133		if (!(s->mode & SSL_MODE_AUTO_RETRY))
1134			{
1135			if (s->s3->rbuf.left == 0) /* no read-ahead left? */
1136				{
1137				BIO *bio;
1138				/* In the case where we try to read application data,
1139				 * but we trigger an SSL handshake, we return -1 with
1140				 * the retry option set.  Otherwise renegotiation may
1141				 * cause nasty problems in the blocking world */
1142				s->rwstate=SSL_READING;
1143				bio=SSL_get_rbio(s);
1144				BIO_clear_retry_flags(bio);
1145				BIO_set_retry_read(bio);
1146				return(-1);
1147				}
1148			}
1149		goto start;
1150		}
1151
1152	switch (rr->type)
1153		{
1154	default:
1155#ifndef OPENSSL_NO_TLS
1156		/* TLS just ignores unknown message types */
1157		if (s->version == TLS1_VERSION)
1158			{
1159			rr->length = 0;
1160			goto start;
1161			}
1162#endif
1163		al=SSL_AD_UNEXPECTED_MESSAGE;
1164		SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1165		goto f_err;
1166	case SSL3_RT_CHANGE_CIPHER_SPEC:
1167	case SSL3_RT_ALERT:
1168	case SSL3_RT_HANDSHAKE:
1169		/* we already handled all of these, with the possible exception
1170		 * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
1171		 * should not happen when type != rr->type */
1172		al=SSL_AD_UNEXPECTED_MESSAGE;
1173		SSLerr(SSL_F_SSL3_READ_BYTES,ERR_R_INTERNAL_ERROR);
1174		goto f_err;
1175	case SSL3_RT_APPLICATION_DATA:
1176		/* At this point, we were expecting handshake data,
1177		 * but have application data.  If the library was
1178		 * running inside ssl3_read() (i.e. in_read_app_data
1179		 * is set) and it makes sense to read application data
1180		 * at this point (session renegotiation not yet started),
1181		 * we will indulge it.
1182		 */
1183		if (s->s3->in_read_app_data &&
1184			(s->s3->total_renegotiations != 0) &&
1185			((
1186				(s->state & SSL_ST_CONNECT) &&
1187				(s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
1188				(s->state <= SSL3_ST_CR_SRVR_HELLO_A)
1189				) || (
1190					(s->state & SSL_ST_ACCEPT) &&
1191					(s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
1192					(s->state >= SSL3_ST_SR_CLNT_HELLO_A)
1193					)
1194				))
1195			{
1196			s->s3->in_read_app_data=2;
1197			return(-1);
1198			}
1199		else
1200			{
1201			al=SSL_AD_UNEXPECTED_MESSAGE;
1202			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1203			goto f_err;
1204			}
1205		}
1206	/* not reached */
1207
1208f_err:
1209	ssl3_send_alert(s,SSL3_AL_FATAL,al);
1210err:
1211	return(-1);
1212	}
1213
1214static int do_change_cipher_spec(SSL *s)
1215	{
1216	int i;
1217	const char *sender;
1218	int slen;
1219
1220	if (s->state & SSL_ST_ACCEPT)
1221		i=SSL3_CHANGE_CIPHER_SERVER_READ;
1222	else
1223		i=SSL3_CHANGE_CIPHER_CLIENT_READ;
1224
1225	if (s->s3->tmp.key_block == NULL)
1226		{
1227		s->session->cipher=s->s3->tmp.new_cipher;
1228		if (!s->method->ssl3_enc->setup_key_block(s)) return(0);
1229		}
1230
1231	if (!s->method->ssl3_enc->change_cipher_state(s,i))
1232		return(0);
1233
1234	/* we have to record the message digest at
1235	 * this point so we can get it before we read
1236	 * the finished message */
1237	if (s->state & SSL_ST_CONNECT)
1238		{
1239		sender=s->method->ssl3_enc->server_finished_label;
1240		slen=s->method->ssl3_enc->server_finished_label_len;
1241		}
1242	else
1243		{
1244		sender=s->method->ssl3_enc->client_finished_label;
1245		slen=s->method->ssl3_enc->client_finished_label_len;
1246		}
1247
1248	s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
1249		&(s->s3->finish_dgst1),
1250		&(s->s3->finish_dgst2),
1251		sender,slen,s->s3->tmp.peer_finish_md);
1252
1253	return(1);
1254	}
1255
1256void ssl3_send_alert(SSL *s, int level, int desc)
1257	{
1258	/* Map tls/ssl alert value to correct one */
1259	desc=s->method->ssl3_enc->alert_value(desc);
1260	if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION)
1261		desc = SSL_AD_HANDSHAKE_FAILURE; /* SSL 3.0 does not have protocol_version alerts */
1262	if (desc < 0) return;
1263	/* If a fatal one, remove from cache */
1264	if ((level == 2) && (s->session != NULL))
1265		SSL_CTX_remove_session(s->ctx,s->session);
1266
1267	s->s3->alert_dispatch=1;
1268	s->s3->send_alert[0]=level;
1269	s->s3->send_alert[1]=desc;
1270	if (s->s3->wbuf.left == 0) /* data still being written out? */
1271		ssl3_dispatch_alert(s);
1272	/* else data is still being written out, we will get written
1273	 * some time in the future */
1274	}
1275
1276int ssl3_dispatch_alert(SSL *s)
1277	{
1278	int i,j;
1279	void (*cb)(const SSL *ssl,int type,int val)=NULL;
1280
1281	s->s3->alert_dispatch=0;
1282	i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0);
1283	if (i <= 0)
1284		{
1285		s->s3->alert_dispatch=1;
1286		}
1287	else
1288		{
1289		/* Alert sent to BIO.  If it is important, flush it now.
1290		 * If the message does not get sent due to non-blocking IO,
1291		 * we will not worry too much. */
1292		if (s->s3->send_alert[0] == SSL3_AL_FATAL)
1293			(void)BIO_flush(s->wbio);
1294
1295		if (s->msg_callback)
1296			s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s, s->msg_callback_arg);
1297
1298		if (s->info_callback != NULL)
1299			cb=s->info_callback;
1300		else if (s->ctx->info_callback != NULL)
1301			cb=s->ctx->info_callback;
1302
1303		if (cb != NULL)
1304			{
1305			j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
1306			cb(s,SSL_CB_WRITE_ALERT,j);
1307			}
1308		}
1309	return(i);
1310	}
1311