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 typedef struct {
  62         void      *key1, *key2;
  63         block128_f block1,block2;
  64 } XTS128_CONTEXT;
  65
  66 int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, u64 secno,
  67         const unsigned char *inp, unsigned char *out,
  68         size_t len, int enc)
  69 {
  70         const union { long one; char little; } is_endian = {1};
  71         union { u64 u[2]; u32 d[4]; u8 c[16]; } tweak, scratch;
  72
  73         if (len<16) return -1;
  74
  75         if (is_endian.little) {
  76                 tweak.u[0] = secno;
  77                 tweak.u[1] = 0;
  78         }
  79         else {
  80                 PUTU32(tweak.c,secno);
  81                 PUTU32(tweak.c+4,secno>>32);
  82                 tweak.u[1] = 0;
  83         }
  84
  85         (*ctx->block2)(tweak.c,tweak.c,ctx->key2);
  86
  87         if (!enc && len%16) len-=16;
  88
  89         while (len>=16) {
  90 #if defined(STRICT_ALIGNMENT)
  91                 memcpy(scratch.c,inp,16);
  92                 scratch.u[0] ^= tweak.u[0];
  93                 scratch.u[1] ^= tweak.u[1];
  94 #else
  95                 scratch.u[0] = ((u64*)inp)[0]^tweak.u[0];
  96                 scratch.u[1] = ((u64*)inp)[1]^tweak.u[1];
  97 #endif
  98                 (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
  99                 scratch.u[0] ^= tweak.u[0];
 100                 scratch.u[1] ^= tweak.u[1];
 101                 memcpy(out,scratch.c,16);
 102                 inp += 16;
 103                 out += 16;
 104                 len -= 16;
 105
 106                 if (is_endian.little) {
 107                         unsigned int carry,res;
 108
 109                         res = 0x87&(((int)tweak.d[3])>>31);
 110                         carry = tweak.u[0]>>63;
 111                         tweak.u[0] = (tweak.u[0]<<1)^res;
 112                         tweak.u[1] = (tweak.u[1]<<1)|carry;
 113                 }
 114                 else {
 115                         unsigned int carry,c,i;
 116
 117                         for (carry=0,i=0;i<16;++i) {
 118                                 c = tweak.c[i];
 119                                 tweak.c[i] = (c<<1)|carry;
 120                                 carry = c>>7;
 121                         }
 122                         tweak.c[0] ^= 0x87&(0-carry);
 123                 }
 124         }
 125         if (len) {
 126                 unsigned int i;
 127
 128                 if (enc) {
 129                         for (i=0;i<len;++i) {
 130                                 u8 c = inp[i];
 131                                 out[i] = scratch.c[i];
 132                                 scratch.c[i] = c;
 133                         }
 134                         scratch.u[0] ^= tweak.u[0];
 135                         scratch.u[1] ^= tweak.u[1];
 136                         (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 137                         scratch.u[0] ^= tweak.u[0];
 138                         scratch.u[1] ^= tweak.u[1];
 139                         memcpy(out-16,scratch.c,16);
 140                 }
 141                 else {
 142                         union { u64 u[2]; u8 c[16]; } tweak1;
 143
 144                         if (is_endian.little) {
 145                                 unsigned int carry,res;
 146
 147                                 res = 0x87&(((int)tweak.d[3])>>31);
 148                                 carry = tweak.u[0]>>63;
 149                                 tweak1.u[0] = (tweak.u[0]<<1)^res;
 150                                 tweak1.u[1] = (tweak.u[1]<<1)|carry;
 151                         }
 152                         else {
 153                                 unsigned int carry,c;
 154
 155                                 for (carry=0,i=0;i<16;++i) {
 156                                         c = tweak.c[i];
 157                                         tweak1.c[i] = (c<<1)|carry;
 158                                         carry = c>>7;
 159                                 }
 160                                 tweak1.c[0] ^= 0x87&(0-carry);
 161                         }
 162 #if defined(STRICT_ALIGNMENT)
 163                         memcpy(scratch.c,inp,16);
 164                         scratch.u[0] ^= tweak1.u[0];
 165                         scratch.u[1] ^= tweak1.u[1];
 166 #else
 167                         scratch.u[0] = ((u64*)inp)[0]^tweak1.u[0];
 168                         scratch.u[1] = ((u64*)inp)[1]^tweak1.u[1];
 169 #endif
 170                         (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 171                         scratch.u[0] ^= tweak1.u[0];
 172                         scratch.u[1] ^= tweak1.u[1];
 173
 174                         for (i=0;i<len;++i) {
 175                                 u8 c = inp[16+i];
 176                                 out[16+i] = scratch.c[i];
 177                                 scratch.c[i] = c;
 178                         }
 179                         scratch.u[0] ^= tweak.u[0];
 180                         scratch.u[1] ^= tweak.u[1];
 181                         (*ctx->block1)(scratch.c,scratch.c,ctx->key1);
 182                         scratch.u[0] ^= tweak.u[0];
 183                         scratch.u[1] ^= tweak.u[1];
 184                         memcpy (out,scratch.c,16);
 185                 }
 186         }
 187
 188         return 0;
 189 }