lib/libcrypto/des/cfb_enc.c

   1 /* $OpenBSD: cfb_enc.c,v 1.13 2015/02/10 09:46:30 miod Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include "des_locl.h"
  60 #include <machine/endian.h>
  61
  62 /* The input and output are loaded in multiples of 8 bits.
  63  * What this means is that if you hame numbits=12 and length=2
  64  * the first 12 bits will be retrieved from the first byte and half
  65  * the second.  The second 12 bits will come from the 3rd and half the 4th
  66  * byte.
  67  */
  68 /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
  69  * will not be compatible with any encryption prior to that date. Ben. */
  70 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
  71                      long length, DES_key_schedule *schedule, DES_cblock *ivec,
  72                      int enc)
  73         {
  74         DES_LONG d0,d1,v0,v1;
  75         unsigned long l=length;
  76         int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8;
  77         DES_LONG ti[2];
  78         unsigned char *iv;
  79 #if BYTE_ORDER != LITTLE_ENDIAN
  80         unsigned char ovec[16];
  81 #else
  82         unsigned int  sh[4];
  83         unsigned char *ovec=(unsigned char *)sh;
  84 #endif
  85
  86         if (numbits<=0 || numbits > 64) return;
  87         iv = &(*ivec)[0];
  88         c2l(iv,v0);
  89         c2l(iv,v1);
  90         if (enc)
  91                 {
  92                 while (l >= (unsigned long)n)
  93                         {
  94                         l-=n;
  95                         ti[0]=v0;
  96                         ti[1]=v1;
  97                         DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
  98                         c2ln(in,d0,d1,n);
  99                         in+=n;
 100                         d0^=ti[0];
 101                         d1^=ti[1];
 102                         l2cn(d0,d1,out,n);
 103                         out+=n;
 104                         /* 30-08-94 - eay - changed because l>>32 and
 105                          * l<<32 are bad under gcc :-( */
 106                         if (numbits == 32)
 107                                 { v0=v1; v1=d0; }
 108                         else if (numbits == 64)
 109                                 { v0=d0; v1=d1; }
 110                         else
 111                                 {
 112 #if BYTE_ORDER != LITTLE_ENDIAN
 113                                 iv=&ovec[0];
 114                                 l2c(v0,iv);
 115                                 l2c(v1,iv);
 116                                 l2c(d0,iv);
 117                                 l2c(d1,iv);
 118 #else
 119                                 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
 120 #endif
 121                                 if (rem==0)
 122                                         memmove(ovec,ovec+num,8);
 123                                 else
 124                                         for(i=0 ; i < 8 ; ++i)
 125                                                 ovec[i]=ovec[i+num]<<rem |
 126                                                         ovec[i+num+1]>>(8-rem);
 127 #if BYTE_ORDER == LITTLE_ENDIAN
 128                                 v0=sh[0], v1=sh[1];
 129 #else
 130                                 iv=&ovec[0];
 131                                 c2l(iv,v0);
 132                                 c2l(iv,v1);
 133 #endif
 134                                 }
 135                         }
 136                 }
 137         else
 138                 {
 139                 while (l >= (unsigned long)n)
 140                         {
 141                         l-=n;
 142                         ti[0]=v0;
 143                         ti[1]=v1;
 144                         DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
 145                         c2ln(in,d0,d1,n);
 146                         in+=n;
 147                         /* 30-08-94 - eay - changed because l>>32 and
 148                          * l<<32 are bad under gcc :-( */
 149                         if (numbits == 32)
 150                                 { v0=v1; v1=d0; }
 151                         else if (numbits == 64)
 152                                 { v0=d0; v1=d1; }
 153                         else
 154                                 {
 155 #if BYTE_ORDER != LITTLE_ENDIAN
 156                                 iv=&ovec[0];
 157                                 l2c(v0,iv);
 158                                 l2c(v1,iv);
 159                                 l2c(d0,iv);
 160                                 l2c(d1,iv);
 161 #else
 162                                 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
 163 #endif
 164                                 if (rem==0)
 165                                         memmove(ovec,ovec+num,8);
 166                                 else
 167                                         for(i=0 ; i < 8 ; ++i)
 168                                                 ovec[i]=ovec[i+num]<<rem |
 169                                                         ovec[i+num+1]>>(8-rem);
 170 #if BYTE_ORDER == LITTLE_ENDIAN
 171                                 v0=sh[0], v1=sh[1];
 172 #else
 173                                 iv=&ovec[0];
 174                                 c2l(iv,v0);
 175                                 c2l(iv,v1);
 176 #endif
 177                                 }
 178                         d0^=ti[0];
 179                         d1^=ti[1];
 180                         l2cn(d0,d1,out,n);
 181                         out+=n;
 182                         }
 183                 }
 184         iv = &(*ivec)[0];
 185         l2c(v0,iv);
 186         l2c(v1,iv);
 187         v0=v1=d0=d1=ti[0]=ti[1]=0;
 188         }
 189