Fix warnings: computed value not use, incompatible pointer initialization

[thirdparty/openssl.git] / ssl / s3_pkt.c

/* 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 <stdio.h>
#include <errno.h>
#define USE_SOCKETS
#include "ssl_locl.h"
#include <openssl/evp.h>
#include <openssl/buffer.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);
        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 */
                }

        /* extend reads should not span multiple packets for DTLS */
        if ( SSL_version(s) == DTLS1_VERSION &&
                extend)
                {
                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;
                }

        max = rb->len - rb->offset;
        if (n > max) /* does not happen */
                {
                SSLerr(SSL_F_SSL3_READ_N,ERR_R_INTERNAL_ERROR);
                return -1;
                }

        if (!s->read_ahead)
                max=n;

        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;
                        return(i);
                        }
                left+=i;
                }

        /* 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;
        unsigned 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);
                                /* Send back error using their
                                 * version number :-) */
                                s->version=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)
                {
                mac_size=EVP_MD_CTX_size(s->read_hash);

                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 >= 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 (mac == NULL || memcmp(md, mac, 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;
        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 (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))
                clear=1;

        if (clear)
                mac_size=0;
        else
                mac_size=EVP_MD_CTX_size(s->write_hash);

        /* '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);
        *(p++)=s->version&0xff;

        /* field where we are to write out packet length */
        plen=p; 
        p+=2;

        /* lets setup the record stuff. */
        wr->data=p;
        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)
                {
                s->method->ssl3_enc->mac(s,&(p[wr->length]),1);
                wr->length+=mac_size;
                wr->input=p;
                wr->data=p;
                }

        /* 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;
                        s->rwstate=SSL_NOTHING;
                        return(s->s3->wpend_ret);
                        }
                else if (i <= 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_buffers(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;
                                }
                        }
                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;
                        }

                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 (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);
                                }
                        }
                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->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 just ignores unknown message types */
                if (s->version == TLS1_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)
                {
                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);
        }

void 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;
        /* 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? */
                s->method->ssl_dispatch_alert(s);
        /* else data is still being written out, we will get written
         * some time in the future */
        }

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);
        }