spp_pkt.c

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

//#define DEBUG
#define MAX_EMPTY_RECORDS 10 /* Might not be needed */
/* Read record from the underlying communication medium 
 * This method attempts to read and decrypt the . */
static int spp_get_record(SSL *s) {
    int ssl_major,ssl_minor,al;
    int enc_err,n,i,ret= -1;
    SSL3_RECORD *rr;
    SSL_SESSION *sess;
    SPP_SLICE *slice;
    SPP_CTX ctx_tmp;
    SPP_CTX *spp_ctx;
    unsigned char *p;
    unsigned char md[EVP_MAX_MD_SIZE];
    short version;
    unsigned mac_size, orig_len;
    size_t extra;
    unsigned empty_record_count = 0;    
    
    rr= &(s->s3->rrec);
    sess=s->session;

    if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
        extra=SSL3_RT_MAX_EXTRA;
    else
        extra=0;
    if (extra && !s->s3->init_extra) {
        /* An application error: 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 < SPP_RT_HEADER_LENGTH)) {
            n=ssl3_read_n(s, SPP_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;
#ifdef DEBUG
            fprintf(stderr, "Received record header: ");
            spp_print_buffer(p, SPP_RT_HEADER_LENGTH);
#endif
            /* 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);
            /* New header fields: slice_id, proxy_id */
            rr->slice_id = *(p++);
            
            if (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
                s->read_stats.handshake_bytes += SPP_RT_HEADER_LENGTH;
            else
                s->read_stats.header_bytes += SPP_RT_HEADER_LENGTH;
            s->read_stats.bytes += rr->length + SPP_RT_HEADER_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) && !s->enc_write_ctx && !s->write_hash)
                        /* Send back error using their minor version number :-) */
                        s->version = (unsigned short)version;
                    al=SSL_AD_PROTOCOL_VERSION;
                    goto f_err;
                }
            }

            if ((version>>8) != SPP_VERSION_MAJOR) {
                SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
                goto err;
            }

            if (rr->length > s->s3->rbuf.len - SPP_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-SPP_RT_HEADER_LENGTH) {
        /* now s->packet_length == SPP_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 == SPP_RT_HEADER_LENGTH + rr->length */
    }

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

    /* At this point, s->packet_length == SPP_RT_HEADER_LNGTH + rr->length,
     * and we have that many bytes in s->packet
     */
    rr->input= &(s->packet[SPP_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 > SPP_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;
    slice = SPP_get_slice_by_id(s, rr->slice_id);
    //printf("Receiving record slice %d\n", rr->slice_id);
    /* Get slice from id if it can be found. */
    /*if (!slice) {
        SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
        goto f_err;
    } */    
    s->read_slice = slice;
    
    /* Setup up the ctx for this read 
     * provided that it is for a slice. */
    if (slice != NULL) {
#ifdef DEBUG
        printf("Encrypted packet:");
        spp_print_buffer(rr->data, rr->length);
#endif
        /* If we are not a proxy, use temporary state. */
        if (s->proxy == 1) {
            spp_ctx = (SPP_CTX*)OPENSSL_malloc(sizeof(SPP_CTX));
        } else {        
            spp_ctx = &(ctx_tmp);
        }
        spp_ctx->mac_length=0;
        spp_ctx->integrity_mac=spp_ctx->read_mac=spp_ctx->write_mac=NULL;
        s->spp_read_ctx = spp_ctx;
    } else {
        s->spp_read_ctx = NULL;
    }
    
    /* Send to ssp_enc for decryption. */
    enc_err = s->method->ssl3_enc->enc(s,0);
    
    /* enc_err is:
     *    0: (in non-constant time) if the record is publically invalid.
     *    1: if the padding is valid
     *    -1: if the padding is invalid */
    if (enc_err == 0) {
        al=SSL_AD_DECRYPTION_FAILED;
        SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
        goto f_err;
    }

#ifdef TLS_DEBUG
printf("dec %d\n",rr->length);
{ unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
printf("\n");
#endif
    
    /*if (slice != NULL) {
        printf("Slice not NULL\n");
        if (EVP_MD_CTX_md(slice->read_mac->read_hash) != NULL) {
            printf("MD not NULL\n");
        }
    }*/
    /* r->length is now the compressed data plus mac */
    /* We can read this record */
    if ((sess != NULL) &&
        (s->enc_read_ctx != NULL) &&
        (slice != NULL) &&
        (EVP_MD_CTX_md(slice->read_mac->read_hash) != NULL)) {
            /* s->read_hash != NULL => mac_size != -1 */
#ifdef DEBUG
            printf("Parsing 3MAC\n");
#endif
            unsigned char *mac = NULL;
            unsigned char mac_tmp[EVP_MAX_MD_SIZE*3];
            
            spp_copy_mac_state(s, slice->read_mac, 0);
            mac_size=EVP_MD_CTX_size(s->read_hash);
            spp_ctx->mac_length = mac_size;                        
            OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
            /* Going to fetch all three MACs at once */
            mac_size = mac_size*3;
                    
            /* kludge: *_cbc_remove_padding passes padding length in rr->type */
            orig_len = rr->length+((unsigned int)rr->type>>8);
            //printf("orig_len=%d, length=%d\n", orig_len, rr->length);

            /* orig_len is the length of the record before any padding was
             * removed. This is public information, as is the MAC in use,
             * therefore we can safely process the record in a different
             * amount of time if it's too short to possibly contain a MAC.
             */
            if (orig_len < mac_size ||
                /* CBC records must have a padding length byte too. */
                (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
                 orig_len < mac_size+1)) {
                    al=SSL_AD_DECODE_ERROR;
                    SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
                    goto f_err;
            }
#ifdef DEBUG
            printf("Decrypted packet:");
            spp_print_buffer(rr->data, rr->length);
#endif
            if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) {
                /* We update the length so that the TLS header bytes
                 * can be constructed correctly but we need to extract
                 * the MAC in constant time from within the record,
                 * without leaking the contents of the padding bytes.
                 * */
                mac = mac_tmp;
                spp_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
                rr->length -= mac_size;
            } else {
                /* In this case there's no padding, so |orig_len|
                 * equals |rec->length| and we checked that there's
                 * enough bytes for |mac_size| above. */
                rr->length -= mac_size;
                mac = &rr->data[rr->length];
            }
            /* Save the locations of the MACs into context. */
            /* We are creating a copy here that must be freed when writing the record out again. */
            if (s->proxy == 1) {
                spp_ctx->read_mac = (unsigned char*)OPENSSL_malloc(mac_size);
                memcpy(spp_ctx->read_mac, mac, mac_size);
            } else {
                spp_ctx->read_mac = mac;
            }
#ifdef DEBUG
            printf("mac: ");
            spp_print_buffer(mac, mac_size);
#endif
            //printf("Grabbed %d bytes of mac, for 3 %d sized macs\n", mac_size, spp_ctx->mac_length);
            s->read_stats.mac_bytes += mac_size;
            mac_size = spp_ctx->mac_length;
            spp_ctx->write_mac = &(spp_ctx->read_mac[mac_size]);
            spp_ctx->integrity_mac = &(spp_ctx->write_mac[mac_size]);

            /* Compute the read mac, the only one we must be able to verify. */
            
            i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
#ifdef DEBUG
            printf("md: ");
            spp_print_buffer(md, mac_size);
#endif
            if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
                enc_err = -1;
                printf("Read MAC failed!\n");
            }
            if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size) {
                enc_err = -1;
                printf("Record too long!\n");
            }            
            
            /* Compare the write mac to see if there have been any illegal writes. */
            if (enc_err >= 0 && slice->write_mac != NULL && EVP_MD_CTX_md(slice->write_mac->read_hash) != NULL) {
                spp_copy_mac_state(s, slice->write_mac, 0);
                mac = spp_ctx->write_mac;
                i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
                if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
                    printf("Write MAC failed!\n");
                    //enc_err = -1; 
                }
            }
            /* Compare the end-to-end integrity mac to see if there have been any writes at all */
            if (enc_err >= 0 && s->def_ctx->read_access && EVP_MD_CTX_md(s->def_ctx->read_mac->read_hash) != NULL) {
                spp_copy_mac_state(s, s->def_ctx->read_mac, 0);
                mac = spp_ctx->integrity_mac;
                i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
                if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) {
                    enc_err = 0;    /* This is not a fatal error. Just important information to know. Expose it somehow to the application */
                    printf("Integrity MAC failed!\n");
                }
            }
    } else if ((sess != NULL) &&
        (s->enc_read_ctx != NULL) &&
        (EVP_MD_CTX_md(s->read_hash) != NULL))
        {
            /* s->read_hash != NULL => mac_size != -1 */
            unsigned char *mac = NULL;
            unsigned char mac_tmp[EVP_MAX_MD_SIZE];
            mac_size=EVP_MD_CTX_size(s->read_hash);
            OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);

#ifdef DEBUG
            printf("Parsing old-style MAC\n");
#endif
            
            /* kludge: *_cbc_remove_padding passes padding length in rr->type */
            orig_len = rr->length+((unsigned int)rr->type>>8);

            /* orig_len is the length of the record before any padding was
             * removed. This is public information, as is the MAC in use,
             * therefore we can safely process the record in a different
             * amount of time if it's too short to possibly contain a MAC.
             */
            if (orig_len < mac_size ||
                /* CBC records must have a padding length byte too. */
                (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
                 orig_len < mac_size+1))
                    {
                    al=SSL_AD_DECODE_ERROR;
                    SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
                    goto f_err;
                    }

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

            s->read_stats.mac_bytes += mac_size;
            i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
            if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
                    enc_err = -1;
            if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
                    enc_err = -1;
    }

    if (enc_err < 0) {
        /* A separate 'decryption_failed' alert was introduced with TLS 1.0,
         * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
         * failure is directly visible from the ciphertext anyway,
         * we should not reveal which kind of error occured -- this
         * might become visible to an attacker (e.g. via a logfile) */
        al=SSL_AD_BAD_RECORD_MAC;
        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 ((s->proxy && rr->length > SPP_RT_MAX_PACKET_SIZE+extra) || (!s->proxy && rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra)) {
        printf("Data too big!!\n");
        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) {
        empty_record_count++;
        if (empty_record_count > MAX_EMPTY_RECORDS) {
            al=SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_RECORD_TOO_SMALL);
            goto f_err;
        }
        goto again;
    }

    if (rr->type == SSL3_RT_APPLICATION_DATA)
        s->read_stats.app_bytes += rr->length;
    else if (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
        s->read_stats.handshake_bytes += rr->length;
    else if (rr->type == SSL3_RT_ALERT)
        s->read_stats.alert_bytes += rr->length;
    
#if 0
    fprintf(stderr, "Ultimate Record type=%d, Length=%d\n", rr->type, rr->length);
#endif

done:
    return(1);

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

int spp_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)) /* Method OK to use with SPP */
            return(-1);

    if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE)) ||
        (peek && (type != SSL3_RT_APPLICATION_DATA))) {
            SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
            return -1;
    }

    /* We are in the middle of a handshake and a handshake msg 
     * has already been received. */
    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=spp_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 && s->s3->rbuf.left == 0)
                                    ssl3_release_read_buffer(s);
                            }
                    } else if (type == SSL3_RT_APPLICATION_DATA) {
                        printf("FATAL ERROR: Application buffer not large enough for record!\n");
                        return -1;
                    }
            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
                    else 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;
                    }

            if (!(s->s3->flags & SSL3_FLAGS_CCS_OK))
                    {
                    al=SSL_AD_UNEXPECTED_MESSAGE;
                    SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_CCS_RECEIVED_EARLY);
                    goto f_err;
                    }

            s->s3->flags &= ~SSL3_FLAGS_CCS_OK;

            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);

#ifdef DEBUG
            printf("Got change cipher spec\n");
#endif
            s->s3->change_cipher_spec=1;
            if (!ssl3_do_change_cipher_spec(s)) {
#ifdef DEBUG
                printf("Error in do cipher spec\n");
#endif
                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 spp_dispatch_alert(SSL *s) {
    int ret;
    SPP_CTX *spp_ctx = s->spp_write_ctx;
    SPP_SLICE *slice = s->write_slice;
    s->spp_write_ctx=NULL;
    s->write_slice=s->def_ctx;
    ret=ssl3_dispatch_alert(s);
    s->spp_write_ctx=spp_ctx;
    s->write_slice=slice;
    return ret;
}

static int do_spp_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;
    SPP_CTX *spp_ctx = s->spp_write_ctx;
    SPP_SLICE *slice = s->write_slice;

    /* 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));
    /* Above does not need to change since format of outgoing 
     * record already set. */

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

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

    if (len == 0 && !create_empty_fragment)
        return 0;

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

    if (slice != NULL) {
        s->enc_write_ctx = slice->read_ciph->enc_write_ctx;
        spp_copy_mac_state(s, slice->read_mac, 1);
    }
    if ((sess == NULL) ||
        (s->enc_write_ctx == NULL) ||
        (EVP_MD_CTX_md(s->write_hash) == NULL)) {
        /* No idea what this means... */
#if 1
            clear=s->enc_write_ctx?0:1;	/* must be AEAD cipher */
#else
            clear=1;
#endif
            mac_size=0;
    } else {
        if (spp_ctx != NULL) {
            mac_size = spp_ctx->mac_length;
        } else {
            mac_size=EVP_MD_CTX_size(s->write_hash);
        }