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d1_enc.c

/* ssl/d1_enc.c */
/* 
 * DTLS implementation written by Nagendra Modadugu
 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
 */
/* ====================================================================
 * Copyright (c) 1998-2005 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).
 *
 */
/* 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.]
 */

#include <stdio.h>
#include "ssl_locl.h"
#ifndef OPENSSL_NO_COMP
#include <openssl/comp.h>
#endif
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/md5.h>
#include <openssl/rand.h>
#ifdef KSSL_DEBUG
#include <openssl/des.h>
#endif

int dtls1_enc(SSL *s, int send)
      {
      SSL3_RECORD *rec;
      EVP_CIPHER_CTX *ds;
      unsigned long l;
      int bs,i,ii,j,k,n=0;
      const EVP_CIPHER *enc;

      if (send)
            {
            if (s->write_hash != NULL)
                  n=EVP_MD_size(s->write_hash);
            ds=s->enc_write_ctx;
            rec= &(s->s3->wrec);
            if (s->enc_write_ctx == NULL)
                  enc=NULL;
            else
                  {
                  enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
                  if ( rec->data != rec->input)
                        /* we can't write into the input stream */
                        fprintf(stderr, "%s:%d: rec->data != rec->input\n",
                              __FILE__, __LINE__);
                  else if ( EVP_CIPHER_block_size(ds->cipher) > 1)
                        {
                        if (RAND_bytes(rec->input, EVP_CIPHER_block_size(ds->cipher)) <= 0)
                              return -1;
                        }
                  }
            }
      else
            {
            if (s->read_hash != NULL)
                  n=EVP_MD_size(s->read_hash);
            ds=s->enc_read_ctx;
            rec= &(s->s3->rrec);
            if (s->enc_read_ctx == NULL)
                  enc=NULL;
            else
                  enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
            }

#ifdef KSSL_DEBUG
      printf("dtls1_enc(%d)\n", send);
#endif    /* KSSL_DEBUG */

      if ((s->session == NULL) || (ds == NULL) ||
            (enc == NULL))
            {
            memmove(rec->data,rec->input,rec->length);
            rec->input=rec->data;
            }
      else
            {
            l=rec->length;
            bs=EVP_CIPHER_block_size(ds->cipher);

            if ((bs != 1) && send)
                  {
                  i=bs-((int)l%bs);

                  /* Add weird padding of upto 256 bytes */

                  /* we need to add 'i' padding bytes of value j */
                  j=i-1;
                  if (s->options & SSL_OP_TLS_BLOCK_PADDING_BUG)
                        {
                        if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
                              j++;
                        }
                  for (k=(int)l; k<(int)(l+i); k++)
                        rec->input[k]=j;
                  l+=i;
                  rec->length+=i;
                  }

#ifdef KSSL_DEBUG
            {
                unsigned long ui;
            printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",
                        (void *)ds,rec->data,rec->input,l);
            printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%ld %ld], %d iv_len\n",
                        ds->buf_len, ds->cipher->key_len,
                        (unsigned long)DES_KEY_SZ,
                  (unsigned long)DES_SCHEDULE_SZ,
                        ds->cipher->iv_len);
            printf("\t\tIV: ");
            for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);
            printf("\n");
            printf("\trec->input=");
            for (ui=0; ui<l; ui++) printf(" %02x", rec->input[ui]);
            printf("\n");
            }
#endif      /* KSSL_DEBUG */

            if (!send)
                  {
                  if (l == 0 || l%bs != 0)
                        {
                        SSLerr(SSL_F_DTLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
                        ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
                        return 0;
                        }
                  }
            
            EVP_Cipher(ds,rec->data,rec->input,l);

#ifdef KSSL_DEBUG
            {
                unsigned long ki;
                printf("\trec->data=");
            for (ki=0; ki<l; ki++)
                        printf(" %02x", rec->data[ki]);  printf("\n");
                }
#endif      /* KSSL_DEBUG */

            if ((bs != 1) && !send)
                  {
                  ii=i=rec->data[l-1]; /* padding_length */
                  i++;
                  if (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
                        {
                        /* First packet is even in size, so check */
                        if ((memcmp(s->s3->read_sequence,
                              "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
                              s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
                        if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
                              i--;
                        }
                  /* TLS 1.0 does not bound the number of padding bytes by the block size.
                   * All of them must have value 'padding_length'. */
                  if (i > (int)rec->length)
                        {
                        /* Incorrect padding. SSLerr() and ssl3_alert are done
                         * by caller: we don't want to reveal whether this is
                         * a decryption error or a MAC verification failure
                         * (see http://www.openssl.org/~bodo/tls-cbc.txt) 
                         */
                        return -1;
                        }
                  for (j=(int)(l-i); j<(int)l; j++)
                        {
                        if (rec->data[j] != ii)
                              {
                              /* Incorrect padding */
                              return -1;
                              }
                        }
                  rec->length-=i;

                  rec->data += bs;    /* skip the implicit IV */
                  rec->input += bs;
                  rec->length -= bs;
                  }
            }
      return(1);
      }


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