s3_pkt.c

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/* ssl/s3_pkt.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * 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 ([email protected]).
 * 
 * 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 ([email protected])"
 *    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 ([email protected])"
 * 
 * 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include <stdio.h>
#include <errno.h>
#define USE_SOCKETS
#include "ssl_locl.h"
#include <openssl/evp.h>
#include <openssl/buffer.h>
#include <openssl/rand.h>

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
             unsigned int len, int create_empty_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_version(s) == DTLS1_VERSION || SSL_version(s) == DTLS1_BAD_VER)
        {
        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 */
        {
        SSLerr(SSL_F_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) */

        clear_sys_error();
        if (s->rbio != NULL)
            {
            s->rwstate=SSL_READING;
            i=BIO_read(s->rbio,pkt+len+left, max-left);
            }
        else
            {
            SSLerr(SSL_F_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_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
                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_version(s) == DTLS1_VERSION || SSL_version(s) == DTLS1_BAD_VER)
            {
            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);
    }

/* 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;
    int mac_size;
    int clear=0;
    size_t extra;
    int decryption_failed_or_bad_record_mac = 0;
    unsigned char *mac = NULL;

    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: SLS_OP_MICROSOFT_BIG_SSLV3_BUFFER
         * set after ssl3_setup_buffers() was done */
        SSLerr(SSL_F_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;

        /* 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->first_packet)
            {
            if (version != s->version)
                {
                SSLerr(SSL_F_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)
            {
            SSLerr(SSL_F_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;
            SSLerr(SSL_F_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;
        SSLerr(SSL_F_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->method->ssl3_enc->enc(s,0);
    if (enc_err <= 0)
        {
        if (enc_err == 0)
            /* SSLerr() and ssl3_send_alert() have been called */
            goto err;

        /* Otherwise enc_err == -1, which indicates bad padding
         * (rec->length has not been changed in this case).
         * To minimize information leaked via timing, we will perform
         * the MAC computation anyway. */
        decryption_failed_or_bad_record_mac = 1;
        }

#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))
        clear=1;

    if (!clear)
        {
        /* !clear => s->read_hash != NULL => mac_size != -1 */
        mac_size=EVP_MD_CTX_size(s->read_hash);
        OPENSSL_assert(mac_size >= 0);

        if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
            {
#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
            al=SSL_AD_RECORD_OVERFLOW;
            SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
            goto f_err;
#else
            decryption_failed_or_bad_record_mac = 1;
#endif          
            }
        /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
        if (rr->length >= (unsigned int)mac_size)
            {
            rr->length -= mac_size;
            mac = &rr->data[rr->length];
            }
        else
            {
            /* record (minus padding) is too short to contain a MAC */
#if 0 /* OK only for stream ciphers */
            al=SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
            goto f_err;
#else
            decryption_failed_or_bad_record_mac = 1;
            rr->length = 0;
#endif
            }
        i=s->method->ssl3_enc->mac(s,md,0);
        if (i < 0 || mac == NULL || memcmp(md, mac, (size_t)mac_size) != 0)
            {
            decryption_failed_or_bad_record_mac = 1;
            }
        }

    if (decryption_failed_or_bad_record_mac)
        {
        /* 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;
        SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
        goto f_err;
        }

    /* r->length is now just compressed */
    if (s->expand != NULL)
        {
        if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra)
            {
            al=SSL_AD_RECORD_OVERFLOW;
            SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
            goto f_err;
            }
        if (!ssl3_do_uncompress(s))
            {
            al=SSL_AD_DECOMPRESSION_FAILURE;
            SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_DECOMPRESSION);
            goto f_err;
            }
        }

    if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra)
        {
        al=SSL_AD_RECORD_OVERFLOW;
        SSLerr(SSL_F_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) 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);
    }

int ssl3_do_uncompress(SSL *ssl)
    {
#ifndef OPENSSL_NO_COMP
    int i;
    SSL3_RECORD *rr;

    rr= &(ssl->s3->rrec);
    i=COMP_expand_block(ssl->expand,rr->comp,
        SSL3_RT_MAX_PLAIN_LENGTH,rr->data,(int)rr->length);
    if (i < 0)
        return(0);
    else
        rr->length=i;
    rr->data=rr->comp;
#endif
    return(1);
    }

int ssl3_do_compress(SSL *ssl)
    {
#ifndef OPENSSL_NO_COMP
    int i;
    SSL3_RECORD *wr;

    wr= &(ssl->s3->wrec);
    i=COMP_compress_block(ssl->compress,wr->data,
        SSL3_RT_MAX_COMPRESSED_LENGTH,
        wr->input,(int)wr->length);
    if (i < 0)
        return(0);
    else
        wr->length=i;

    wr->input=wr->data;
#endif
    return(1);
    }

/* 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;
    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)
            {
            SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
            return -1;
            }
        }

    n=(len-tot);
    for (;;)
        {
        if (n > s->max_send_fragment)
            nw=s->max_send_fragment;
        else
            nw=n;

        i=do_ssl3_write(s, type, &(buf[tot]), nw, 0);
        if (i <= 0)
            {
            s->s3->wnum=tot;
            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 empty fragment
             * in ciphersuites with known-IV weakness: */
            s->s3->empty_fragment_done = 0;
            
            return tot+i;
            }

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

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
             unsigned int len, int create_empty_fragment)
    {
    unsigned char *p,*plen;
    int i,mac_size,clear=0;
    int prefix_len=0;
    int eivlen;
    long align=0;
    SSL3_RECORD *wr;
    SSL3_BUFFER *wb=&(s->s3->wbuf);
    SSL_SESSION *sess;

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

    /* 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 (len == 0 && !create_empty_fragment)
        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))
        {
#if 1
        clear=s->enc_write_ctx?0:1; /* must be AEAD cipher */
#else
        clear=1;
#endif
        mac_size=0;
        }
    else
        {
        mac_size=EVP_MD_CTX_size(s->write_hash);
        if (mac_size < 0)
            goto err;
        }

    /* 'create_empty_fragment' is true only when this function calls itself */
    if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done)
        {
        /* countermeasure against known-IV weakness in CBC ciphersuites
         * (see http://www.openssl.org/~bodo/tls-cbc.txt) */

        if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
            {
            /* recursive function call with 'create_empty_fragment' set;
             * this prepares and buffers the data for an empty fragment
             * (these 'prefix_len' bytes are sent out later
             * together with the actual payload) */
            prefix_len = do_ssl3_write(s, type, buf, 0, 1);
            if (prefix_len <= 0)
                goto err;

            if (prefix_len >
        (SSL3_RT_HEADER_LENGTH + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD))
                {
                /* insufficient space */
                SSLerr(SSL_F_DO_SSL3_WRITE, ERR_R_INTERNAL_ERROR);
                goto err;
                }
            }
        
        s->s3->empty_fragment_done = 1;
        }

    if (create_empty_fragment)
        {
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
        /* extra fragment would be couple of cipher blocks,
         * which would be multiple of SSL3_ALIGN_PAYLOAD, so
         * if we want to align the real payload, then we can
         * just pretent we simply have two headers. */
        align = (long)wb->buf + 2*SSL3_RT_HEADER_LENGTH;
        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;

    *(p++)=(s->version>>8);
    /* Some servers hang if iniatial client hello is larger than 256
     * bytes and record version number > TLS 1.0
     */
    if (s->state == SSL3_ST_CW_CLNT_HELLO_B
                && TLS1_get_version(s) > TLS1_VERSION)
        *(p++) = 0x1;
    else
        *(p++)=s->version&0xff;

    /* field where we are to write out packet length */
    plen=p; 
    p+=2;
    /* Explicit IV length, block ciphers and TLS version 1.1 or later */
    if (s->enc_write_ctx && s->version >= TLS1_1_VERSION)
        {
        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;
            }
        /* Need explicit part of IV for GCM mode */
        else if (mode == EVP_CIPH_GCM_MODE)
            eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
        else
            eivlen = 0;
        }
    else 
        eivlen = 0;

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

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

    /* first we compress */
    if (s->compress != NULL)
        {
        if (!ssl3_do_compress(s))
            {
            SSLerr(SSL_F_DO_SSL3_WRITE,SSL_R_COMPRESSION_FAILURE);
            goto err;
            }
        }
    else
        {
        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->method->ssl3_enc->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;
        }

    /* ssl3_enc can only have an error on read */
    s->method->ssl3_enc->enc(s,1);

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

    /* 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 (create_empty_fragment)
        {
        /* we are in a recursive call;
         * just return the length, don't write out anything here
         */
        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))
        {
        SSLerr(SSL_F_SSL3_WRITE_PENDING,SSL_R_BAD_WRITE_RETRY);
        return(-1);
        }

    for (;;)
        {
        clear_sys_error();
        if (s->wbio != NULL)
            {
            s->rwstate=SSL_WRITING;
            i=BIO_write(s->wbio,
                (char *)&(wb->buf[wb->offset]),
                (unsigned int)wb->left);
            }
        else
            {
            SSLerr(SSL_F_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_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
                ssl3_release_write_buffer(s);
            s->rwstate=SSL_NOTHING;
            return(s->s3->wpend_ret);
            }
        else if (i <= 0) {
            if (s->version == DTLS1_VERSION ||
                s->version == DTLS1_BAD_VER) {
                /* 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;
        }
    }

/* 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;

    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) && type) ||
        (peek && (type != SSL3_RT_APPLICATION_DATA)))
        {
        SSLerr(SSL_F_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)
            {
            SSLerr(SSL_F_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;
        SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
        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;
            SSLerr(SSL_F_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)
                    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.
     */
        {
        unsigned int dest_maxlen = 0;
        unsigned char *dest = NULL;
        unsigned int *dest_len = NULL;

        if (rr->type == SSL3_RT_HANDSHAKE)
            {
            dest_maxlen = sizeof s->s3->handshake_fragment;
            dest = s->s3->handshake_fragment;
            dest_len = &s->s3->handshake_fragment_len;
            }
        else if (rr->type == SSL3_RT_ALERT)
            {
            dest_maxlen = sizeof s->s3->alert_fragment;
            dest = s->s3->alert_fragment;
            dest_len = &s->s3->alert_fragment_len;
            }
#ifndef OPENSSL_NO_HEARTBEATS
        else if (rr->type == TLS1_RT_HEARTBEAT)
            {
            tls1_process_heartbeat(s);

            /* Exit and notify application to read again */
            rr->length = 0;
            s->rwstate=SSL_READING;
            BIO_clear_retry_flags(SSL_get_rbio(s));
            BIO_set_retry_read(SSL_get_rbio(s));
            return(-1);
            }
#endif

        if (dest_maxlen > 0)
            {
            n = dest_maxlen - *dest_len; /* available space in 'dest' */
            if (rr->length < n)
                n = rr->length; /* available bytes */

            /* now move 'n' bytes: */
            while (n-- > 0)
                {
                dest[(*dest_len)++] = rr->data[rr->off++];
                rr->length--;
                }

            if (*dest_len < dest_maxlen)
                goto start; /* fragment was too small */
            }
        }

    /* s->s3->handshake_fragment_len == 4  iff  rr->type == SSL3_RT_HANDSHAKE;
     * s->s3->alert_fragment_len == 2      iff  rr->type == SSL3_RT_ALERT.
     * (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;
            SSLerr(SSL_F_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->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
            !s->s3->renegotiate)
            {
            ssl3_renegotiate(s);
            if (ssl3_renegotiate_check(s))
                {
                i=s->handshake_func(s);
                if (i < 0) return(i);
                if (i == 0)
                    {
                    SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
                    return(-1);
                    }

                if (!(s->mode & SSL_MODE_AUTO_RETRY))
                    {
                    if (s->s3->rbuf.left == 0) /* no read-ahead left? */
                        {
                        BIO *bio;
                        /* In the case where we try to read application data,
                         * but we trigger an SSL handshake, we return -1 with
                         * the retry option set.  Otherwise renegotiation may
                         * cause nasty problems in the blocking world */
                        s->rwstate=SSL_READING;
                        bio=SSL_get_rbio(s);
                        BIO_clear_retry_flags(bio);
                        BIO_set_retry_read(bio);
                        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 we are a server and get a client hello when renegotiation isn't
     * allowed send back a no renegotiation alert and carry on.
     * WARNING: experimental code, needs reviewing (steve)
     */
    if (s->server &&
        SSL_is_init_finished(s) &&
            !s->s3->send_connection_binding &&
        (s->version > SSL3_VERSION) &&
        (s->s3->handshake_fragment_len >= 4) &&
        (s->s3->handshake_fragment[0] == SSL3_MT_CLIENT_HELLO) &&
        (s->session != NULL) && (s->session->cipher != NULL) &&
        !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
        
        {
        /*s->s3->handshake_fragment_len = 0;*/
        rr->length = 0;
        ssl3_send_alert(s,SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
        goto start;
        }
    if (s->s3->alert_fragment_len >= 2)
        {
        int alert_level = s->s3->alert_fragment[0];
        int alert_descr = s->s3->alert_fragment[1];

        s->s3->alert_fragment_len = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_ALERT, s->s3->alert_fragment, 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;
                SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_NO_RENEGOTIATION);
                goto f_err;
                }
#ifdef SSL_AD_MISSING_SRP_USERNAME
            if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
                return(0);
#endif
            }
        else if (alert_level == 2) /* fatal */
            {
            char tmp[16];

            s->rwstate=SSL_NOTHING;
            s->s3->fatal_alert = alert_descr;
            SSLerr(SSL_F_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;
            SSLerr(SSL_F_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;
            SSLerr(SSL_F_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;
            SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_CCS_RECEIVED_EARLY);
            goto f_err;
            }

        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->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
            {
#if 0 /* worked only because C operator preferences are not as expected (and
       * because this is not really needed for clients except for detecting
       * protocol violations): */
            s->state=SSL_ST_BEFORE|(s->server)
                ?SSL_ST_ACCEPT
                :SSL_ST_CONNECT;
#else
            s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#endif
            s->renegotiate=1;
            s->new_session=1;
            }
        i=s->handshake_func(s);
        if (i < 0) return(i);
        if (i == 0)
            {
            SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
            return(-1);
            }

        if (!(s->mode & SSL_MODE_AUTO_RETRY))
            {
            if (s->s3->rbuf.left == 0) /* no read-ahead left? */
                {
                BIO *bio;
                /* In the case where we try to read application data,
                 * but we trigger an SSL handshake, we return -1 with
                 * the retry option set.  Otherwise renegotiation may
                 * cause nasty problems in the blocking world */
                s->rwstate=SSL_READING;
                bio=SSL_get_rbio(s);
                BIO_clear_retry_flags(bio);
                BIO_set_retry_read(bio);
                return(-1);
                }
            }
        goto start;
        }

    switch (rr->type)
        {
    default:
#ifndef OPENSSL_NO_TLS
        /* 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;
            }
#endif
        al=SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_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;
        SSLerr(SSL_F_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;
            SSLerr(SSL_F_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;
    const char *sender;
    int slen;

    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) 
            {
            /* might happen if dtls1_read_bytes() calls this */
            SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC,SSL_R_CCS_RECEIVED_EARLY);
            return (0);
            }

        s->session->cipher=s->s3->tmp.new_cipher;
        if (!s->method->ssl3_enc->setup_key_block(s)) return(0);
        }

    if (!s->method->ssl3_enc->change_cipher_state(s,i))
        return(0);

    /* we have to record the message digest at
     * this point so we can get it before we read
     * the finished message */
    if (s->state & SSL_ST_CONNECT)
        {
        sender=s->method->ssl3_enc->server_finished_label;
        slen=s->method->ssl3_enc->server_finished_label_len;
        }
    else
        {
        sender=s->method->ssl3_enc->client_finished_label;
        slen=s->method->ssl3_enc->client_finished_label_len;
        }

    s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
        sender,slen,s->s3->tmp.peer_finish_md);

    return(1);
    }

int ssl3_send_alert(SSL *s, int level, int desc)
    {
    /* Map tls/ssl alert value to correct one */
    desc=s->method->ssl3_enc->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);
    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);
    }