crypto/modes/xts128.c

   1 /* ====================================================================
   2  * Copyright (c) 2011 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 #include <openssl/crypto.h>
  51 #include "modes_lcl.h"
  52 #include <string.h>
  53
  54 #ifndef MODES_DEBUG
  55 # ifndef NDEBUG
  56 #  define NDEBUG
  57 # endif
  58 #endif
  59 #include <assert.h>
  60
  61 int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, const unsigned char iv[16],
  62         const unsigned char *inp, unsigned char *out,
  63         size_t len, int enc)
  64 {
  65         const union { long one; char little; } is_endian = {1};
  66         union { u64 u[2]; u32 d[4]; u8 c[16]; } tweak, scratch;
  67         unsigned int i;
  68
  69         if (len<16) return -1;
  70
  71         memcpy(tweak.c, iv, 16);
  72
  73         (*ctx->block2)(tweak.c,tweak.c,ctx->key2);
  74
  75         if (!enc && (len%16)) len-=16;
  76
  77         while (len>=16) {
  78 #if defined(STRICT_ALIGNMENT)
  79                 memcpy(scratch.c,inp,16);
  80                 scratch.u[0] ^= tweak.u[0];
  81                 scratch.u[1] ^= tweak.u[1];
  82 #else
  83                 scratch.u[0] = ((u64*)inp)[0]^tweak.u[0];
  84                 scratch.u[1] = ((u64*)inp)[1]^tweak.u[1];
  85 #endif
  86                 (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
  87 #if defined(STRICT_ALIGNMENT)
  88                 scratch.u[0] ^= tweak.u[0];
  89                 scratch.u[1] ^= tweak.u[1];
  90                 memcpy(out,scratch.c,16);
  91 #else
  92                 ((u64*)out)[0] = scratch.u[0]^=tweak.u[0];
  93                 ((u64*)out)[1] = scratch.u[1]^=tweak.u[1];
  94 #endif
  95                 inp += 16;
  96                 out += 16;
  97                 len -= 16;
  98
  99                 if (len==0)     return 0;
 100
 101                 if (is_endian.little) {
 102                         unsigned int carry,res;
 103
 104                         res = 0x87&(((int)tweak.d[3])>>31);
 105                         carry = (unsigned int)(tweak.u[0]>>63);
 106                         tweak.u[0] = (tweak.u[0]<<1)^res;
 107                         tweak.u[1] = (tweak.u[1]<<1)|carry;
 108                 }
 109                 else {
 110                         size_t c;
 111
 112                         for (c=0,i=0;i<16;++i) {
 113                                 /*+ substitutes for |, because c is 1 bit */
 114                                 c += ((size_t)tweak.c[i])<<1;
 115                                 tweak.c[i] = (u8)c;
 116                                 c = c>>8;
 117                         }
 118                         tweak.c[0] ^= (u8)(0x87&(0-c));
 119                 }
 120         }
 121         if (enc) {
 122                 for (i=0;i<len;++i) {
 123                         u8 c = inp[i];
 124                         out[i] = scratch.c[i];
 125                         scratch.c[i] = c;
 126                 }
 127                 scratch.u[0] ^= tweak.u[0];
 128                 scratch.u[1] ^= tweak.u[1];
 129                 (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 130                 scratch.u[0] ^= tweak.u[0];
 131                 scratch.u[1] ^= tweak.u[1];
 132                 memcpy(out-16,scratch.c,16);
 133         }
 134         else {
 135                 union { u64 u[2]; u8 c[16]; } tweak1;
 136
 137                 if (is_endian.little) {
 138                         unsigned int carry,res;
 139
 140                         res = 0x87&(((int)tweak.d[3])>>31);
 141                         carry = (unsigned int)(tweak.u[0]>>63);
 142                         tweak1.u[0] = (tweak.u[0]<<1)^res;
 143                         tweak1.u[1] = (tweak.u[1]<<1)|carry;
 144                 }
 145                 else {
 146                         size_t c;
 147
 148                         for (c=0,i=0;i<16;++i) {
 149                                 /*+ substitutes for |, because c is 1 bit */
 150                                 c += ((size_t)tweak.c[i])<<1;
 151                                 tweak1.c[i] = (u8)c;
 152                                 c = c>>8;
 153                         }
 154                         tweak1.c[0] ^= (u8)(0x87&(0-c));
 155                 }
 156 #if defined(STRICT_ALIGNMENT)
 157                 memcpy(scratch.c,inp,16);
 158                 scratch.u[0] ^= tweak1.u[0];
 159                 scratch.u[1] ^= tweak1.u[1];
 160 #else
 161                 scratch.u[0] = ((u64*)inp)[0]^tweak1.u[0];
 162                 scratch.u[1] = ((u64*)inp)[1]^tweak1.u[1];
 163 #endif
 164                 (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 165                 scratch.u[0] ^= tweak1.u[0];
 166                 scratch.u[1] ^= tweak1.u[1];
 167
 168                 for (i=0;i<len;++i) {
 169                         u8 c = inp[16+i];
 170                         out[16+i] = scratch.c[i];
 171                         scratch.c[i] = c;
 172                 }
 173                 scratch.u[0] ^= tweak.u[0];
 174                 scratch.u[1] ^= tweak.u[1];
 175                 (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 176 #if defined(STRICT_ALIGNMENT)
 177                 scratch.u[0] ^= tweak.u[0];
 178                 scratch.u[1] ^= tweak.u[1];
 179                 memcpy (out,scratch.c,16);
 180 #else
 181                 ((u64*)out)[0] = scratch.u[0]^tweak.u[0];
 182                 ((u64*)out)[1] = scratch.u[1]^tweak.u[1];
 183 #endif
 184         }
 185
 186         return 0;
 187 }