boringssl/ssl/s3_pkt.c

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com). */

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>

#include <openssl/buf.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/rand.h>

#include "ssl_locl.h"

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
			 unsigned int len, char fragment, char is_fragment);
static int ssl3_get_record(SSL *s);

int ssl3_read_n(SSL *s, int n, int max, int extend)
	{
	/* If extend == 0, obtain new n-byte packet; if extend == 1, increase
	 * packet by another n bytes.
	 * The packet will be in the sub-array of s->s3->rbuf.buf specified
	 * by s->packet and s->packet_length.
	 * (If s->read_ahead is set, 'max' bytes may be stored in rbuf
	 * [plus s->packet_length bytes if extend == 1].)
	 */
	int i,len,left;
	long align=0;
	unsigned char *pkt;
	SSL3_BUFFER *rb;

	if (n <= 0) return n;

	rb    = &(s->s3->rbuf);
	if (rb->buf == NULL)
		if (!ssl3_setup_read_buffer(s))
			return -1;

	left  = rb->left;
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
	align = (long)rb->buf + SSL3_RT_HEADER_LENGTH;
	align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
#endif

	if (!extend)
		{
		/* start with empty packet ... */
		if (left == 0)
			rb->offset = align;
		else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH)
			{
			/* check if next packet length is large
			 * enough to justify payload alignment... */
			pkt = rb->buf + rb->offset;
			if (pkt[0] == SSL3_RT_APPLICATION_DATA
			    && (pkt[3]<<8|pkt[4]) >= 128)
				{
				/* Note that even if packet is corrupted
				 * and its length field is insane, we can
				 * only be led to wrong decision about
				 * whether memmove will occur or not.
				 * Header values has no effect on memmove
				 * arguments and therefore no buffer
				 * overrun can be triggered. */
				memmove (rb->buf+align,pkt,left);
				rb->offset = align;
				}
			}
		s->packet = rb->buf + rb->offset;
		s->packet_length = 0;
		/* ... now we can act as if 'extend' was set */
		}

	/* For DTLS/UDP reads should not span multiple packets
	 * because the read operation returns the whole packet
	 * at once (as long as it fits into the buffer). */
	if (SSL_IS_DTLS(s))
		{
		if (left > 0 && n > left)
			n = left;
		}

	/* if there is enough in the buffer from a previous read, take some */
	if (left >= n)
		{
		s->packet_length+=n;
		rb->left=left-n;
		rb->offset+=n;
		return(n);
		}

	/* else we need to read more data */

	len = s->packet_length;
	pkt = rb->buf+align;
	/* Move any available bytes to front of buffer:
	 * 'len' bytes already pointed to by 'packet',
	 * 'left' extra ones at the end */
	if (s->packet != pkt) /* len > 0 */
		{
		memmove(pkt, s->packet, len+left);
		s->packet = pkt;
		rb->offset = len + align;
		}

	if (n > (int)(rb->len - rb->offset)) /* does not happen */
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_read_n, ERR_R_INTERNAL_ERROR);
		return -1;
		}

	if (!s->read_ahead)
		/* ignore max parameter */
		max = n;
	else
		{
		if (max < n)
			max = n;
		if (max > (int)(rb->len - rb->offset))
			max = rb->len - rb->offset;
		}

	while (left < n)
		{
		/* Now we have len+left bytes at the front of s->s3->rbuf.buf
		 * and need to read in more until we have len+n (up to
		 * len+max if possible) */

		ERR_clear_system_error();
		if (s->rbio != NULL)
			{
			s->rwstate=SSL_READING;
			i=BIO_read(s->rbio,pkt+len+left, max-left);
			}
		else
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_read_n, SSL_R_READ_BIO_NOT_SET);
			i = -1;
			}

		if (i <= 0)
			{
			rb->left = left;
			if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
				!SSL_IS_DTLS(s))
				if (len+left == 0)
					ssl3_release_read_buffer(s);
			return(i);
			}
		left+=i;
		/* reads should *never* span multiple packets for DTLS because
		 * the underlying transport protocol is message oriented as opposed
		 * to byte oriented as in the TLS case. */
		if (SSL_IS_DTLS(s))
			{
			if (n > left)
				n = left; /* makes the while condition false */
			}
		}

	/* done reading, now the book-keeping */
	rb->offset += n;
	rb->left = left - n;
	s->packet_length += n;
	s->rwstate=SSL_NOTHING;
	return(n);
	}

/* MAX_EMPTY_RECORDS defines the number of consecutive, empty records that will
 * be processed per call to ssl3_get_record. Without this limit an attacker
 * could send empty records at a faster rate than we can process and cause
 * ssl3_get_record to loop forever. */
#define MAX_EMPTY_RECORDS 32

/* Call this to get a new input record.
 * It will return <= 0 if more data is needed, normally due to an error
 * or non-blocking IO.
 * When it finishes, one packet has been decoded and can be found in
 * ssl->s3->rrec.type    - is the type of record
 * ssl->s3->rrec.data, 	 - data
 * ssl->s3->rrec.length, - number of bytes
 */
/* used only by ssl3_read_bytes */
static int ssl3_get_record(SSL *s)
	{
	int ssl_major,ssl_minor,al;
	int enc_err,n,i,ret= -1;
	SSL3_RECORD *rr;
	SSL_SESSION *sess;
	unsigned char *p;
	unsigned char md[EVP_MAX_MD_SIZE];
	short version;
	unsigned mac_size, orig_len;
	size_t extra;
	unsigned empty_record_count = 0;

	rr= &(s->s3->rrec);
	sess=s->session;

	if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
		extra=SSL3_RT_MAX_EXTRA;
	else
		extra=0;
	if (extra && !s->s3->init_extra)
		{
		/* An application error: SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
		 * set after ssl3_setup_buffers() was done */
		OPENSSL_PUT_ERROR(SSL, ssl3_get_record, ERR_R_INTERNAL_ERROR);
		return -1;
		}

again:
	/* check if we have the header */
	if (	(s->rstate != SSL_ST_READ_BODY) ||
		(s->packet_length < SSL3_RT_HEADER_LENGTH)) 
		{
		n=ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
		if (n <= 0) return(n); /* error or non-blocking */
		s->rstate=SSL_ST_READ_BODY;

		p=s->packet;
		if (s->msg_callback)
			s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s, s->msg_callback_arg);

		/* Pull apart the header into the SSL3_RECORD */
		rr->type= *(p++);
		ssl_major= *(p++);
		ssl_minor= *(p++);
		version=(ssl_major<<8)|ssl_minor;
		n2s(p,rr->length);
#if 0
fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
#endif

		/* Lets check version */
		if (s->s3->have_version)
			{
			if (version != s->version)
				{
				OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
                                if ((s->version & 0xFF00) == (version & 0xFF00))
                                	/* Send back error using their minor version number :-) */
					s->version = (unsigned short)version;
				al=SSL_AD_PROTOCOL_VERSION;
				goto f_err;
				}
			}

		if ((version>>8) != SSL3_VERSION_MAJOR)
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_WRONG_VERSION_NUMBER);
			goto err;
			}

		if (rr->length > s->s3->rbuf.len - SSL3_RT_HEADER_LENGTH)
			{
			al=SSL_AD_RECORD_OVERFLOW;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_PACKET_LENGTH_TOO_LONG);
			goto f_err;
			}

		/* now s->rstate == SSL_ST_READ_BODY */
		}

	/* s->rstate == SSL_ST_READ_BODY, get and decode the data */

	if (rr->length > s->packet_length-SSL3_RT_HEADER_LENGTH)
		{
		/* now s->packet_length == SSL3_RT_HEADER_LENGTH */
		i=rr->length;
		n=ssl3_read_n(s,i,i,1);
		if (n <= 0) return(n); /* error or non-blocking io */
		/* now n == rr->length,
		 * and s->packet_length == SSL3_RT_HEADER_LENGTH + rr->length */
		}

	s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */

	/* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
	 * and we have that many bytes in s->packet
	 */
	rr->input= &(s->packet[SSL3_RT_HEADER_LENGTH]);

	/* ok, we can now read from 's->packet' data into 'rr'
	 * rr->input points at rr->length bytes, which
	 * need to be copied into rr->data by either
	 * the decryption or by the decompression
	 * When the data is 'copied' into the rr->data buffer,
	 * rr->input will be pointed at the new buffer */ 

	/* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
	 * rr->length bytes of encrypted compressed stuff. */

	/* check is not needed I believe */
	if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
		{
		al=SSL_AD_RECORD_OVERFLOW;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
		goto f_err;
		}

	/* decrypt in place in 'rr->input' */
	rr->data=rr->input;

	enc_err = s->enc_method->enc(s,0);
	/* enc_err is:
	 *    0: (in non-constant time) if the record is publically invalid.
	 *    1: if the padding is valid
	 *    -1: if the padding is invalid */
	if (enc_err == 0)
		{
		al=SSL_AD_DECRYPTION_FAILED;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
		goto f_err;
		}

#ifdef TLS_DEBUG
printf("dec %d\n",rr->length);
{ unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
printf("\n");
#endif

	/* r->length is now the compressed data plus mac */
	if ((sess != NULL) &&
	    (s->enc_read_ctx != NULL) &&
	    (EVP_MD_CTX_md(s->read_hash) != NULL))
		{
		/* s->read_hash != NULL => mac_size != -1 */
		unsigned char *mac = NULL;
		unsigned char mac_tmp[EVP_MAX_MD_SIZE];
		mac_size=EVP_MD_CTX_size(s->read_hash);
		assert(mac_size <= EVP_MAX_MD_SIZE);

		/* kludge: *_cbc_remove_padding passes padding length in rr->type */
		orig_len = rr->length+((unsigned int)rr->type>>8);

		/* orig_len is the length of the record before any padding was
		 * removed. This is public information, as is the MAC in use,
		 * therefore we can safely process the record in a different
		 * amount of time if it's too short to possibly contain a MAC.
		 */
		if (orig_len < mac_size ||
		    /* CBC records must have a padding length byte too. */
		    (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
		     orig_len < mac_size+1))
			{
			al=SSL_AD_DECODE_ERROR;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_LENGTH_TOO_SHORT);
			goto f_err;
			}

		if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
			{
			/* We update the length so that the TLS header bytes
			 * can be constructed correctly but we need to extract
			 * the MAC in constant time from within the record,
			 * without leaking the contents of the padding bytes.
			 * */
			mac = mac_tmp;
			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
			rr->length -= mac_size;
			}
		else
			{
			/* In this case there's no padding, so |orig_len|
			 * equals |rec->length| and we checked that there's
			 * enough bytes for |mac_size| above. */
			rr->length -= mac_size;
			mac = &rr->data[rr->length];
			}

		i=s->enc_method->mac(s,md,0 /* not send */);
		if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
			enc_err = -1;
		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
			enc_err = -1;
		}

	if (enc_err < 0)
		{
		/* A separate 'decryption_failed' alert was introduced with TLS 1.0,
		 * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
		 * failure is directly visible from the ciphertext anyway,
		 * we should not reveal which kind of error occured -- this
		 * might become visible to an attacker (e.g. via a logfile) */
		al=SSL_AD_BAD_RECORD_MAC;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
		goto f_err;
		}

	if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra)
		{
		al=SSL_AD_RECORD_OVERFLOW;
		OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_DATA_LENGTH_TOO_LONG);
		goto f_err;
		}

	rr->off=0;
	/* So at this point the following is true
	 * ssl->s3->rrec.type 	is the type of record
	 * ssl->s3->rrec.length	== number of bytes in record
	 * ssl->s3->rrec.off	== offset to first valid byte
	 * ssl->s3->rrec.data	== where to take bytes from, increment
	 *			   after use :-).
	 */

	/* we have pulled in a full packet so zero things */
	s->packet_length=0;

	/* just read a 0 length packet */
	if (rr->length == 0)
		{
		empty_record_count++;
		if (empty_record_count > MAX_EMPTY_RECORDS)
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_get_record, SSL_R_TOO_MANY_EMPTY_FRAGMENTS);
			goto f_err;
			}
		goto again;
		}

#if 0
fprintf(stderr, "Ultimate Record type=%d, Length=%d\n", rr->type, rr->length);
#endif

	return(1);

f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
	return(ret);
	}

/* Call this to write data in records of type 'type'
 * It will return <= 0 if not all data has been sent or non-blocking IO.
 */
int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
	{
	const unsigned char *buf=buf_;
	unsigned int tot,n,nw;
	int i;

	s->rwstate=SSL_NOTHING;
	assert(s->s3->wnum <= INT_MAX);
	tot=s->s3->wnum;
	s->s3->wnum=0;

	if (SSL_in_init(s) && !s->in_handshake)
		{
		i=s->handshake_func(s);
		if (i < 0) return(i);
		if (i == 0)
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
			return -1;
			}
		}

	/* ensure that if we end up with a smaller value of data to write 
	 * out than the the original len from a write which didn't complete 
	 * for non-blocking I/O and also somehow ended up avoiding 
	 * the check for this in ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as
	 * it must never be possible to end up with (len-tot) as a large
	 * number that will then promptly send beyond the end of the users
	 * buffer ... so we trap and report the error in a way the user
	 * will notice
	 */
	if (len < 0 || (size_t)len < tot)
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_write_bytes, SSL_R_BAD_LENGTH);
		return(-1);
		}

	n=(len-tot);
	for (;;)
		{
		/* max contains the maximum number of bytes that we can put
		 * into a record. */
		unsigned max = s->max_send_fragment;
		/* fragment is true if do_ssl3_write should send the first byte
		 * in its own record in order to randomise a CBC IV. */
		int fragment = 0;

		if (n > 1 &&
		    s->s3->need_record_splitting &&
		    type == SSL3_RT_APPLICATION_DATA &&
		    !s->s3->record_split_done)
			{
			fragment = 1;
			/* record_split_done records that the splitting has
			 * been done in case we hit an SSL_WANT_WRITE condition.
			 * In that case, we don't need to do the split again. */
			s->s3->record_split_done = 1;
			}

		if (n > max)
			nw=max;
		else
			nw=n;

		i=do_ssl3_write(s, type, &(buf[tot]), nw, fragment, 0);
		if (i <= 0)
			{
			s->s3->wnum=tot;
			s->s3->record_split_done = 0;
			return i;
			}

		if ((i == (int)n) ||
			(type == SSL3_RT_APPLICATION_DATA &&
			 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
			{
			/* next chunk of data should get another prepended,
			 * one-byte fragment in ciphersuites with known-IV
			 * weakness. */
			s->s3->record_split_done = 0;
			return tot+i;
			}

		n-=i;
		tot+=i;
		}
	}

/* do_ssl3_write writes an SSL record of the given type. If |fragment| is 1
 * then it splits the record into a one byte record and a record with the rest
 * of the data in order to randomise a CBC IV. If |is_fragment| is true then
 * this call resulted from do_ssl3_write calling itself in order to create that
 * one byte fragment. */
static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
			 unsigned int len, char fragment, char is_fragment)
	{
	unsigned char *p,*plen;
	int i,mac_size;
	int prefix_len=0;
	int eivlen;
	long align=0;
	SSL3_RECORD *wr;
	SSL3_BUFFER *wb=&(s->s3->wbuf);
	SSL_SESSION *sess;

	/* first check if there is a SSL3_BUFFER still being written
	 * out.  This will happen with non blocking IO */
	if (wb->left != 0)
		return(ssl3_write_pending(s,type,buf,len));

	/* If we have an alert to send, lets send it */
	if (s->s3->alert_dispatch)
		{
		i=s->method->ssl_dispatch_alert(s);
		if (i <= 0)
			return(i);
		/* if it went, fall through and send more stuff */
		}

	if (wb->buf == NULL)
		if (!ssl3_setup_write_buffer(s))
			return -1;

	if (len == 0)
		return 0;

	wr= &(s->s3->wrec);
	sess=s->session;

	if (	(sess == NULL) ||
		(s->enc_write_ctx == NULL) ||
		(EVP_MD_CTX_md(s->write_hash) == NULL))
		{
		mac_size=0;
		}
	else
		{
		mac_size=EVP_MD_CTX_size(s->write_hash);
		if (mac_size < 0)
			goto err;
		}

	if (fragment)
		{
		/* countermeasure against known-IV weakness in CBC ciphersuites
		 * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
		prefix_len = do_ssl3_write(s, type, buf, 1 /* length */,
					   0 /* fragment */,
					   1 /* is_fragment */);
		if (prefix_len <= 0)
			goto err;

		if (prefix_len > (SSL3_RT_HEADER_LENGTH +
				  SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD))
			{
			/* insufficient space */
			OPENSSL_PUT_ERROR(SSL, do_ssl3_write, ERR_R_INTERNAL_ERROR);
			goto err;
			}
		}

	if (is_fragment)
		{
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
		/* The extra fragment would be couple of cipher blocks, and
		 * that will be a multiple of SSL3_ALIGN_PAYLOAD. So, if we
		 * want to align the real payload, we can just pretend that we
		 * have two headers and a byte. */
		align = (long)wb->buf + 2*SSL3_RT_HEADER_LENGTH + 1;
		align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
#endif
		p = wb->buf + align;
		wb->offset  = align;
		}
	else if (prefix_len)
		{
		p = wb->buf + wb->offset + prefix_len;
		}
	else
		{
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
		align = (long)wb->buf + SSL3_RT_HEADER_LENGTH;
		align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
#endif
		p = wb->buf + align;
		wb->offset  = align;
		}

	/* write the header */

	*(p++)=type&0xff;
	wr->type=type;

	/* Some servers hang if initial ClientHello is larger than 256
	 * bytes and record version number > TLS 1.0. */
	if (!s->s3->have_version && s->version > SSL3_VERSION)
		{
		*(p++) = TLS1_VERSION >> 8;
		*(p++) = TLS1_VERSION & 0xff;
		}
	else
		{
		*(p++) = s->version >> 8;
		*(p++) = s->version & 0xff;
		}

	/* field where we are to write out packet length */
	plen=p;
	p+=2;
	/* Explicit IV length, block ciphers appropriate version flag */
	if (s->enc_write_ctx && SSL_USE_EXPLICIT_IV(s))
		{
		int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
		if (mode == EVP_CIPH_CBC_MODE)
			{
			eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
			if (eivlen <= 1)
				eivlen = 0;
			}
		else
			eivlen = 0;
		}
	else if (s->aead_write_ctx != NULL &&
		 s->aead_write_ctx->variable_nonce_included_in_record)
		{
		eivlen = s->aead_write_ctx->variable_nonce_len;
		}
	else
		eivlen = 0;

	/* lets setup the record stuff. */
	wr->data=p + eivlen;
	wr->length=(int)(len - (fragment != 0));
	wr->input=(unsigned char *)buf + (fragment != 0);

	/* we now 'read' from wr->input, wr->length bytes into
	 * wr->data */

        memcpy(wr->data,wr->input,wr->length);
        wr->input=wr->data;

	/* we should still have the output to wr->data and the input
	 * from wr->input.  Length should be wr->length.
	 * wr->data still points in the wb->buf */

	if (mac_size != 0)
		{
		if (s->enc_method->mac(s,&(p[wr->length + eivlen]),1) < 0)
			goto err;
		wr->length+=mac_size;
		}

	wr->input=p;
	wr->data=p;

	if (eivlen)
		{
	/*	if (RAND_pseudo_bytes(p, eivlen) <= 0)
			goto err; */
		wr->length += eivlen;
		}

	if (s->enc_method->enc(s, 1) < 1)
		goto err;

	/* record length after mac and block padding */
	s2n(wr->length,plen);

	if (s->msg_callback)
		s->msg_callback(1, 0, SSL3_RT_HEADER, plen - 5, 5, s, s->msg_callback_arg);

	/* we should now have
	 * wr->data pointing to the encrypted data, which is
	 * wr->length long */
	wr->type=type; /* not needed but helps for debugging */
	wr->length+=SSL3_RT_HEADER_LENGTH;

	if (is_fragment)
		{
		/* we are in a recursive call; just return the length, don't
		 * write out anything. */
		return wr->length;
		}

	/* now let's set up wb */
	wb->left = prefix_len + wr->length;

	/* memorize arguments so that ssl3_write_pending can detect bad write retries later */
	s->s3->wpend_tot=len;
	s->s3->wpend_buf=buf;
	s->s3->wpend_type=type;
	s->s3->wpend_ret=len;

	/* we now just need to write the buffer */
	return ssl3_write_pending(s,type,buf,len);
err:
	return -1;
	}

/* if s->s3->wbuf.left != 0, we need to call this */
int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
	unsigned int len)
	{
	int i;
	SSL3_BUFFER *wb=&(s->s3->wbuf);

/* XXXX */
	if ((s->s3->wpend_tot > (int)len)
		|| ((s->s3->wpend_buf != buf) &&
			!(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER))
		|| (s->s3->wpend_type != type))
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BAD_WRITE_RETRY);
		return(-1);
		}

	for (;;)
		{
		ERR_clear_system_error();
		if (s->wbio != NULL)
			{
			s->rwstate=SSL_WRITING;
			i=BIO_write(s->wbio,
				(char *)&(wb->buf[wb->offset]),
				(unsigned int)wb->left);
			}
		else
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_write_pending, SSL_R_BIO_NOT_SET);
			i= -1;
			}
		if (i == wb->left)
			{
			wb->left=0;
			wb->offset+=i;
			if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
				!SSL_IS_DTLS(s))
				ssl3_release_write_buffer(s);
			s->rwstate=SSL_NOTHING;
			return(s->s3->wpend_ret);
			}
		else if (i <= 0) {
			if (SSL_IS_DTLS(s)) {
				/* For DTLS, just drop it. That's kind of the whole
				   point in using a datagram service */
				wb->left = 0;
			}
			return(i);
		}
		wb->offset+=i;
		wb->left-=i;
		}
	}

/* ssl3_expect_change_cipher_spec informs the record layer that a
 * ChangeCipherSpec record is required at this point. If a Handshake record is
 * received before ChangeCipherSpec, the connection will fail. Moreover, if
 * there are unprocessed handshake bytes, the handshake will also fail and the
 * function returns zero. Otherwise, the function returns one. */
int ssl3_expect_change_cipher_spec(SSL *s)
	{
	if (s->s3->handshake_fragment_len > 0 || s->s3->tmp.reuse_message)
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_expect_change_cipher_spec, SSL_R_UNPROCESSED_HANDSHAKE_DATA);
		return 0;
		}
	s->s3->flags |= SSL3_FLAGS_EXPECT_CCS;
	return 1;
	}

/* Return up to 'len' payload bytes received in 'type' records.
 * 'type' is one of the following:
 *
 *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
 *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
 *   -  0 (during a shutdown, no data has to be returned)
 *
 * If we don't have stored data to work from, read a SSL/TLS record first
 * (possibly multiple records if we still don't have anything to return).
 *
 * This function must handle any surprises the peer may have for us, such as
 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
 * a surprise, but handled as if it were), or renegotiation requests.
 * Also if record payloads contain fragments too small to process, we store
 * them until there is enough for the respective protocol (the record protocol
 * may use arbitrary fragmentation and even interleaving):
 *     Change cipher spec protocol
 *             just 1 byte needed, no need for keeping anything stored
 *     Alert protocol
 *             2 bytes needed (AlertLevel, AlertDescription)
 *     Handshake protocol
 *             4 bytes needed (HandshakeType, uint24 length) -- we just have
 *             to detect unexpected Client Hello and Hello Request messages
 *             here, anything else is handled by higher layers
 *     Application data protocol
 *             none of our business
 */
int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
	{
	int al,i,j,ret;
	unsigned int n;
	SSL3_RECORD *rr;
	void (*cb)(const SSL *ssl,int type2,int val)=NULL;
	uint8_t alert_buffer[2];

	if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
		if (!ssl3_setup_read_buffer(s))
			return(-1);

	if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE)) ||
	    (peek && (type != SSL3_RT_APPLICATION_DATA)))
		{
		OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR);
		return -1;
		}

	if ((type == SSL3_RT_HANDSHAKE) && (s->s3->handshake_fragment_len > 0))
		/* (partially) satisfy request from storage */
		{
		unsigned char *src = s->s3->handshake_fragment;
		unsigned char *dst = buf;
		unsigned int k;

		/* peek == 0 */
		n = 0;
		while ((len > 0) && (s->s3->handshake_fragment_len > 0))
			{
			*dst++ = *src++;
			len--; s->s3->handshake_fragment_len--;
			n++;
			}
		/* move any remaining fragment bytes: */
		for (k = 0; k < s->s3->handshake_fragment_len; k++)
			s->s3->handshake_fragment[k] = *src++;
		return n;
	}

	/* Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */

	if (!s->in_handshake && SSL_in_init(s))
		{
		/* type == SSL3_RT_APPLICATION_DATA */
		i=s->handshake_func(s);
		if (i < 0) return(i);
		if (i == 0)
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
			return(-1);
			}
		}
start:
	s->rwstate=SSL_NOTHING;

	/* s->s3->rrec.type	    - is the type of record
	 * s->s3->rrec.data,    - data
	 * s->s3->rrec.off,     - offset into 'data' for next read
	 * s->s3->rrec.length,  - number of bytes. */
	rr = &(s->s3->rrec);

	/* get new packet if necessary */
	if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
		{
		ret=ssl3_get_record(s);
		if (ret <= 0) return(ret);
		}

	/* we now have a packet which can be read and processed */

	if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
	                               * reset by ssl3_get_finished */
		&& (rr->type != SSL3_RT_HANDSHAKE))
		{
		al=SSL_AD_UNEXPECTED_MESSAGE;
		OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
		goto f_err;
		}

	/* If we are expecting a ChangeCipherSpec, it is illegal to receive a
	 * Handshake record. */
	if (rr->type == SSL3_RT_HANDSHAKE && (s->s3->flags & SSL3_FLAGS_EXPECT_CCS))
		{
		al = SSL_AD_UNEXPECTED_MESSAGE;
		OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_HANDSHAKE_RECORD_BEFORE_CCS);
		goto f_err;
		}

	/* If the other end has shut down, throw anything we read away
	 * (even in 'peek' mode) */
	if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
		{
		rr->length=0;
		s->rwstate=SSL_NOTHING;
		return(0);
		}

	if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
		{
		/* make sure that we are not getting application data when we
		 * are doing a handshake for the first time */
		if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
			(s->enc_read_ctx == NULL))
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_APP_DATA_IN_HANDSHAKE);
			goto f_err;
			}

		if (len <= 0) return(len);

		if ((unsigned int)len > rr->length)
			n = rr->length;
		else
			n = (unsigned int)len;

		memcpy(buf,&(rr->data[rr->off]),n);
		if (!peek)
			{
			rr->length-=n;
			rr->off+=n;
			if (rr->length == 0)
				{
				s->rstate=SSL_ST_READ_HEADER;
				rr->off=0;
				if (s->mode & SSL_MODE_RELEASE_BUFFERS && s->s3->rbuf.left == 0)
					ssl3_release_read_buffer(s);
				}
			}
		return(n);
		}


	/* If we get here, then type != rr->type; if we have a handshake
	 * message, then it was unexpected (Hello Request or Client Hello). */

	/* In case of record types for which we have 'fragment' storage,
	 * fill that so that we can process the data at a fixed place.
	 */

	if (rr->type == SSL3_RT_HANDSHAKE)
		{
		const size_t size = sizeof(s->s3->handshake_fragment);
		const size_t avail = size - s->s3->handshake_fragment_len;
		const size_t todo = (rr->length < avail) ? rr->length : avail;
		memcpy(s->s3->handshake_fragment + s->s3->handshake_fragment_len,
			&rr->data[rr->off], todo);
		rr->off += todo;
		rr->length -= todo;
		s->s3->handshake_fragment_len += todo;
		if (s->s3->handshake_fragment_len < size)
			{
			goto start; /* fragment was too small */
			}
		}
	else if (rr->type == SSL3_RT_ALERT)
		{
		/* Note that this will still allow multiple alerts to
		 * be processed in the same record */
		if (rr->length < sizeof(alert_buffer))
			{
			al = SSL_AD_DECODE_ERROR;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_ALERT);
			goto f_err;
			}
		memcpy(alert_buffer, &rr->data[rr->off], sizeof(alert_buffer));
		rr->off += sizeof(alert_buffer);
		rr->length -= sizeof(alert_buffer);
		}

	/* s->s3->handshake_fragment_len == 4  iff  rr->type == SSL3_RT_HANDSHAKE;
	 * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */

	/* If we are a client, check for an incoming 'Hello Request': */
	if ((!s->server) &&
		(s->s3->handshake_fragment_len >= 4) &&
		(s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
		(s->session != NULL) && (s->session->cipher != NULL))
		{
		s->s3->handshake_fragment_len = 0;

		if ((s->s3->handshake_fragment[1] != 0) ||
			(s->s3->handshake_fragment[2] != 0) ||
			(s->s3->handshake_fragment[3] != 0))
			{
			al=SSL_AD_DECODE_ERROR;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_HELLO_REQUEST);
			goto f_err;
			}

		if (s->msg_callback)
			s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->s3->handshake_fragment, 4, s, s->msg_callback_arg);

		if (SSL_is_init_finished(s) && !s->s3->renegotiate)
			{
			ssl3_renegotiate(s);
			if (ssl3_renegotiate_check(s))
				{
				i=s->handshake_func(s);
				if (i < 0) return(i);
				if (i == 0)
					{
					OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
					return(-1);
					}
				}
			}
		/* we either finished a handshake or ignored the request,
		 * now try again to obtain the (application) data we were asked for */
		goto start;
		}

	if (rr->type == SSL3_RT_ALERT)
		{
		uint8_t alert_level = alert_buffer[0];
		uint8_t alert_descr = alert_buffer[1];

		if (s->msg_callback)
			s->msg_callback(0, s->version, SSL3_RT_ALERT, alert_buffer, 2, s, s->msg_callback_arg);

		if (s->info_callback != NULL)
			cb=s->info_callback;
		else if (s->ctx->info_callback != NULL)
			cb=s->ctx->info_callback;

		if (cb != NULL)
			{
			j = (alert_level << 8) | alert_descr;
			cb(s, SSL_CB_READ_ALERT, j);
			}

		if (alert_level == 1) /* warning */
			{
			s->s3->warn_alert = alert_descr;
			if (alert_descr == SSL_AD_CLOSE_NOTIFY)
				{
				s->shutdown |= SSL_RECEIVED_SHUTDOWN;
				return(0);
				}
			/* This is a warning but we receive it if we requested
			 * renegotiation and the peer denied it. Terminate with
			 * a fatal alert because if application tried to
			 * renegotiatie it presumably had a good reason and
			 * expects it to succeed.
			 *
			 * In future we might have a renegotiation where we
			 * don't care if the peer refused it where we carry on.
			 */
			else if (alert_descr == SSL_AD_NO_RENEGOTIATION)
				{
				al = SSL_AD_HANDSHAKE_FAILURE;
				OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_NO_RENEGOTIATION);
				goto f_err;
				}
			}
		else if (alert_level == 2) /* fatal */
			{
			char tmp[16];

			s->rwstate=SSL_NOTHING;
			s->s3->fatal_alert = alert_descr;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_AD_REASON_OFFSET + alert_descr);
			BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
			ERR_add_error_data(2,"SSL alert number ",tmp);
			s->shutdown|=SSL_RECEIVED_SHUTDOWN;
			SSL_CTX_remove_session(s->ctx,s->session);
			return(0);
			}
		else
			{
			al=SSL_AD_ILLEGAL_PARAMETER;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNKNOWN_ALERT_TYPE);
			goto f_err;
			}

		goto start;
		}

	if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
		{
		s->rwstate=SSL_NOTHING;
		rr->length=0;
		return(0);
		}

	if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
		{
		/* 'Change Cipher Spec' is just a single byte, so we know
		 * exactly what the record payload has to look like */
		if (	(rr->length != 1) || (rr->off != 0) ||
			(rr->data[0] != SSL3_MT_CCS))
			{
			al=SSL_AD_ILLEGAL_PARAMETER;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_CHANGE_CIPHER_SPEC);
			goto f_err;
			}

		/* Check we have a cipher to change to */
		if (s->s3->tmp.new_cipher == NULL)
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
			goto f_err;
			}

		if (!(s->s3->flags & SSL3_FLAGS_EXPECT_CCS))
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_CCS_RECEIVED_EARLY);
			goto f_err;
			}

		s->s3->flags &= ~SSL3_FLAGS_EXPECT_CCS;

		rr->length=0;

		if (s->msg_callback)
			s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s, s->msg_callback_arg);

		s->s3->change_cipher_spec=1;
		if (!ssl3_do_change_cipher_spec(s))
			goto err;
		else
			goto start;
		}

	/* Unexpected handshake message (Client Hello, or protocol violation) */
	if ((s->s3->handshake_fragment_len >= 4) &&	!s->in_handshake)
		{
		if ((s->state&SSL_ST_MASK) == SSL_ST_OK)
			{
			s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
			s->renegotiate=1;
			s->new_session=1;
			}
		i=s->handshake_func(s);
		if (i < 0) return(i);
		if (i == 0)
			{
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
			return(-1);
			}

		goto start;
		}

	switch (rr->type)
		{
	default:
		/* TLS up to v1.1 just ignores unknown message types:
		 * TLS v1.2 give an unexpected message alert.
		 */
		if (s->version >= TLS1_VERSION && s->version <= TLS1_1_VERSION)
			{
			rr->length = 0;
			goto start;
			}
		al=SSL_AD_UNEXPECTED_MESSAGE;
		OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNEXPECTED_RECORD);
		goto f_err;
	case SSL3_RT_CHANGE_CIPHER_SPEC:
	case SSL3_RT_ALERT:
	case SSL3_RT_HANDSHAKE:
		/* we already handled all of these, with the possible exception
		 * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
		 * should not happen when type != rr->type */
		al=SSL_AD_UNEXPECTED_MESSAGE;
		OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, ERR_R_INTERNAL_ERROR);
		goto f_err;
	case SSL3_RT_APPLICATION_DATA:
		/* At this point, we were expecting handshake data,
		 * but have application data.  If the library was
		 * running inside ssl3_read() (i.e. in_read_app_data
		 * is set) and it makes sense to read application data
		 * at this point (session renegotiation not yet started),
		 * we will indulge it.
		 */
		if (s->s3->in_read_app_data &&
			(s->s3->total_renegotiations != 0) &&
			((
				(s->state & SSL_ST_CONNECT) &&
				(s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
				(s->state <= SSL3_ST_CR_SRVR_HELLO_A)
				) || (
					(s->state & SSL_ST_ACCEPT) &&
					(s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
					(s->state >= SSL3_ST_SR_CLNT_HELLO_A)
					)
				))
			{
			s->s3->in_read_app_data=2;
			return(-1);
			}
		else
			{
			al=SSL_AD_UNEXPECTED_MESSAGE;
			OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_UNEXPECTED_RECORD);
			goto f_err;
			}
		}
	/* not reached */

f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
	return(-1);
	}

int ssl3_do_change_cipher_spec(SSL *s)
	{
	int i;

	if (s->state & SSL_ST_ACCEPT)
		i=SSL3_CHANGE_CIPHER_SERVER_READ;
	else
		i=SSL3_CHANGE_CIPHER_CLIENT_READ;

	if (s->s3->tmp.key_block == NULL)
		{
		if (s->session == NULL || s->session->master_key_length == 0)
			{
			/* might happen if dtls1_read_bytes() calls this */
			OPENSSL_PUT_ERROR(SSL, ssl3_do_change_cipher_spec, SSL_R_CCS_RECEIVED_EARLY);
			return (0);
			}

		s->session->cipher=s->s3->tmp.new_cipher;
		if (!s->enc_method->setup_key_block(s)) return(0);
		}

	if (!s->enc_method->change_cipher_state(s,i))
		return(0);

	return(1);
	}

int ssl3_send_alert(SSL *s, int level, int desc)
	{
	/* Map tls/ssl alert value to correct one */
	desc=s->enc_method->alert_value(desc);
	if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION)
		desc = SSL_AD_HANDSHAKE_FAILURE; /* SSL 3.0 does not have protocol_version alerts */
	if (desc < 0) return -1;
	/* If a fatal one, remove from cache */
	if ((level == 2) && (s->session != NULL))
		SSL_CTX_remove_session(s->ctx,s->session);

	s->s3->alert_dispatch=1;
	s->s3->send_alert[0]=level;
	s->s3->send_alert[1]=desc;
	if (s->s3->wbuf.left == 0) /* data still being written out? */
		return s->method->ssl_dispatch_alert(s);
	/* else data is still being written out, we will get written
	 * some time in the future */
	return -1;
	}

int ssl3_dispatch_alert(SSL *s)
	{
	int i,j;
	void (*cb)(const SSL *ssl,int type,int val)=NULL;

	s->s3->alert_dispatch=0;
	i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0, 0);
	if (i <= 0)
		{
		s->s3->alert_dispatch=1;
		}
	else
		{
		/* Alert sent to BIO.  If it is important, flush it now.
		 * If the message does not get sent due to non-blocking IO,
		 * we will not worry too much. */
		if (s->s3->send_alert[0] == SSL3_AL_FATAL)
			(void)BIO_flush(s->wbio);

		if (s->msg_callback)
			s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s, s->msg_callback_arg);

		if (s->info_callback != NULL)
			cb=s->info_callback;
		else if (s->ctx->info_callback != NULL)
			cb=s->ctx->info_callback;

		if (cb != NULL)
			{
			j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
			cb(s,SSL_CB_WRITE_ALERT,j);
			}
		}
	return(i);
	}