Cryptlib/OpenSSL/crypto/modes/cfb128.c

   1 /* ====================================================================
   2  * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  *
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in
  13  *    the documentation and/or other materials provided with the
  14  *    distribution.
  15  *
  16  * 3. All advertising materials mentioning features or use of this
  17  *    software must display the following acknowledgment:
  18  *    "This product includes software developed by the OpenSSL Project
  19  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  20  *
  21  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  22  *    endorse or promote products derived from this software without
  23  *    prior written permission. For written permission, please contact
  24  *    openssl-core@openssl.org.
  25  *
  26  * 5. Products derived from this software may not be called "OpenSSL"
  27  *    nor may "OpenSSL" appear in their names without prior written
  28  *    permission of the OpenSSL Project.
  29  *
  30  * 6. Redistributions of any form whatsoever must retain the following
  31  *    acknowledgment:
  32  *    "This product includes software developed by the OpenSSL Project
  33  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  36  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  38  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  39  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  40  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  41  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  42  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  43  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  44  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  45  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  46  * OF THE POSSIBILITY OF SUCH DAMAGE.
  47  * ====================================================================
  48  *
  49  */
  50
  51 #include <openssl/crypto.h>
  52 #include "modes_lcl.h"
  53 #include <string.h>
  54
  55 #ifndef MODES_DEBUG
  56 # ifndef NDEBUG
  57 #  define NDEBUG
  58 # endif
  59 #endif
  60 #include <assert.h>
  61
  62 /*
  63  * The input and output encrypted as though 128bit cfb mode is being used.
  64  * The extra state information to record how much of the 128bit block we have
  65  * used is contained in *num;
  66  */
  67 void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
  68                            size_t len, const void *key,
  69                            unsigned char ivec[16], int *num,
  70                            int enc, block128_f block)
  71 {
  72     unsigned int n;
  73     size_t l = 0;
  74
  75     assert(in && out && key && ivec && num);
  76
  77     n = *num;
  78
  79     if (enc) {
  80 #if !defined(OPENSSL_SMALL_FOOTPRINT)
  81         if (16 % sizeof(size_t) == 0) { /* always true actually */
  82             do {
  83                 while (n && len) {
  84                     *(out++) = ivec[n] ^= *(in++);
  85                     --len;
  86                     n = (n + 1) % 16;
  87                 }
  88 # if defined(STRICT_ALIGNMENT)
  89                 if (((size_t)in | (size_t)out | (size_t)ivec) %
  90                     sizeof(size_t) != 0)
  91                     break;
  92 # endif
  93                 while (len >= 16) {
  94                     (*block) (ivec, ivec, key);
  95                     for (; n < 16; n += sizeof(size_t)) {
  96                         *(size_t *)(out + n) =
  97                             *(size_t *)(ivec + n) ^= *(size_t *)(in + n);
  98                     }
  99                     len -= 16;
 100                     out += 16;
 101                     in += 16;
 102                     n = 0;
 103                 }
 104                 if (len) {
 105                     (*block) (ivec, ivec, key);
 106                     while (len--) {
 107                         out[n] = ivec[n] ^= in[n];
 108                         ++n;
 109                     }
 110                 }
 111                 *num = n;
 112                 return;
 113             } while (0);
 114         }
 115         /* the rest would be commonly eliminated by x86* compiler */
 116 #endif
 117         while (l < len) {
 118             if (n == 0) {
 119                 (*block) (ivec, ivec, key);
 120             }
 121             out[l] = ivec[n] ^= in[l];
 122             ++l;
 123             n = (n + 1) % 16;
 124         }
 125         *num = n;
 126     } else {
 127 #if !defined(OPENSSL_SMALL_FOOTPRINT)
 128         if (16 % sizeof(size_t) == 0) { /* always true actually */
 129             do {
 130                 while (n && len) {
 131                     unsigned char c;
 132                     *(out++) = ivec[n] ^ (c = *(in++));
 133                     ivec[n] = c;
 134                     --len;
 135                     n = (n + 1) % 16;
 136                 }
 137 # if defined(STRICT_ALIGNMENT)
 138                 if (((size_t)in | (size_t)out | (size_t)ivec) %
 139                     sizeof(size_t) != 0)
 140                     break;
 141 # endif
 142                 while (len >= 16) {
 143                     (*block) (ivec, ivec, key);
 144                     for (; n < 16; n += sizeof(size_t)) {
 145                         size_t t = *(size_t *)(in + n);
 146                         *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
 147                         *(size_t *)(ivec + n) = t;
 148                     }
 149                     len -= 16;
 150                     out += 16;
 151                     in += 16;
 152                     n = 0;
 153                 }
 154                 if (len) {
 155                     (*block) (ivec, ivec, key);
 156                     while (len--) {
 157                         unsigned char c;
 158                         out[n] = ivec[n] ^ (c = in[n]);
 159                         ivec[n] = c;
 160                         ++n;
 161                     }
 162                 }
 163                 *num = n;
 164                 return;
 165             } while (0);
 166         }
 167         /* the rest would be commonly eliminated by x86* compiler */
 168 #endif
 169         while (l < len) {
 170             unsigned char c;
 171             if (n == 0) {
 172                 (*block) (ivec, ivec, key);
 173             }
 174             out[l] = ivec[n] ^ (c = in[l]);
 175             ivec[n] = c;
 176             ++l;
 177             n = (n + 1) % 16;
 178         }
 179         *num = n;
 180     }
 181 }
 182
 183 /*
 184  * This expects a single block of size nbits for both in and out. Note that
 185  * it corrupts any extra bits in the last byte of out
 186  */
 187 static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out,
 188                                int nbits, const void *key,
 189                                unsigned char ivec[16], int enc,
 190                                block128_f block)
 191 {
 192     int n, rem, num;
 193     unsigned char ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't
 194                                      * use) one byte off the end */
 195
 196     if (nbits <= 0 || nbits > 128)
 197         return;
 198
 199     /* fill in the first half of the new IV with the current IV */
 200     memcpy(ovec, ivec, 16);
 201     /* construct the new IV */
 202     (*block) (ivec, ivec, key);
 203     num = (nbits + 7) / 8;
 204     if (enc)                    /* encrypt the input */
 205         for (n = 0; n < num; ++n)
 206             out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
 207     else                        /* decrypt the input */
 208         for (n = 0; n < num; ++n)
 209             out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
 210     /* shift ovec left... */
 211     rem = nbits % 8;
 212     num = nbits / 8;
 213     if (rem == 0)
 214         memcpy(ivec, ovec + num, 16);
 215     else
 216         for (n = 0; n < 16; ++n)
 217             ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
 218
 219     /* it is not necessary to cleanse ovec, since the IV is not secret */
 220 }
 221
 222 /* N.B. This expects the input to be packed, MS bit first */
 223 void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out,
 224                              size_t bits, const void *key,
 225                              unsigned char ivec[16], int *num,
 226                              int enc, block128_f block)
 227 {
 228     size_t n;
 229     unsigned char c[1], d[1];
 230
 231     assert(in && out && key && ivec && num);
 232     assert(*num == 0);
 233
 234     for (n = 0; n < bits; ++n) {
 235         c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
 236         cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
 237         out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
 238             ((d[0] & 0x80) >> (unsigned int)(n % 8));
 239     }
 240 }
 241
 242 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
 243                              size_t length, const void *key,
 244                              unsigned char ivec[16], int *num,
 245                              int enc, block128_f block)
 246 {
 247     size_t n;
 248
 249     assert(in && out && key && ivec && num);
 250     assert(*num == 0);
 251
 252     for (n = 0; n < length; ++n)
 253         cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);
 254 }