release/src/router/openssl/crypto/modes/ctr128.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 /* NOTE: the IV/counter CTR mode is big-endian.  The code itself
  63  * is endian-neutral. */
  64
  65 /* increment counter (128-bit int) by 1 */
  66 static void ctr128_inc(unsigned char *counter) {
  67         u32 n=16;
  68         u8  c;
  69
  70         do {
  71                 --n;
  72                 c = counter[n];
  73                 ++c;
  74                 counter[n] = c;
  75                 if (c) return;
  76         } while (n);
  77 }
  78
  79 #if !defined(OPENSSL_SMALL_FOOTPRINT)
  80 static void ctr128_inc_aligned(unsigned char *counter) {
  81         size_t *data,c,n;
  82         const union { long one; char little; } is_endian = {1};
  83
  84         if (is_endian.little) {
  85                 ctr128_inc(counter);
  86                 return;
  87         }
  88
  89         data = (size_t *)counter;
  90         n = 16/sizeof(size_t);
  91         do {
  92                 --n;
  93                 c = data[n];
  94                 ++c;
  95                 data[n] = c;
  96                 if (c) return;
  97         } while (n);
  98 }
  99 #endif
 100
 101 /* The input encrypted as though 128bit counter mode is being
 102  * used.  The extra state information to record how much of the
 103  * 128bit block we have used is contained in *num, and the
 104  * encrypted counter is kept in ecount_buf.  Both *num and
 105  * ecount_buf must be initialised with zeros before the first
 106  * call to CRYPTO_ctr128_encrypt().
 107  *
 108  * This algorithm assumes that the counter is in the x lower bits
 109  * of the IV (ivec), and that the application has full control over
 110  * overflow and the rest of the IV.  This implementation takes NO
 111  * responsability for checking that the counter doesn't overflow
 112  * into the rest of the IV when incremented.
 113  */
 114 void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
 115                         size_t len, const void *key,
 116                         unsigned char ivec[16], unsigned char ecount_buf[16],
 117                         unsigned int *num, block128_f block)
 118 {
 119         unsigned int n;
 120         size_t l=0;
 121
 122         assert(in && out && key && ecount_buf && num);
 123         assert(*num < 16);
 124
 125         n = *num;
 126
 127 #if !defined(OPENSSL_SMALL_FOOTPRINT)
 128         if (16%sizeof(size_t) == 0) do { /* always true actually */
 129                 while (n && len) {
 130                         *(out++) = *(in++) ^ ecount_buf[n];
 131                         --len;
 132                         n = (n+1) % 16;
 133                 }
 134
 135 #if defined(STRICT_ALIGNMENT)
 136                 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
 137                         break;
 138 #endif
 139                 while (len>=16) {
 140                         (*block)(ivec, ecount_buf, key);
 141                         ctr128_inc_aligned(ivec);
 142                         for (; n<16; n+=sizeof(size_t))
 143                                 *(size_t *)(out+n) =
 144                                 *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n);
 145                         len -= 16;
 146                         out += 16;
 147                         in  += 16;
 148                         n = 0;
 149                 }
 150                 if (len) {
 151                         (*block)(ivec, ecount_buf, key);
 152                         ctr128_inc_aligned(ivec);
 153                         while (len--) {
 154                                 out[n] = in[n] ^ ecount_buf[n];
 155                                 ++n;
 156                         }
 157                 }
 158                 *num = n;
 159                 return;
 160         } while(0);
 161         /* the rest would be commonly eliminated by x86* compiler */
 162 #endif
 163         while (l<len) {
 164                 if (n==0) {
 165                         (*block)(ivec, ecount_buf, key);
 166                         ctr128_inc(ivec);
 167                 }
 168                 out[l] = in[l] ^ ecount_buf[n];
 169                 ++l;
 170                 n = (n+1) % 16;
 171         }
 172
 173         *num=n;
 174 }
 175
 176 /* increment upper 96 bits of 128-bit counter by 1 */
 177 static void ctr96_inc(unsigned char *counter) {
 178         u32 n=12;
 179         u8  c;
 180
 181         do {
 182                 --n;
 183                 c = counter[n];
 184                 ++c;
 185                 counter[n] = c;
 186                 if (c) return;
 187         } while (n);
 188 }
 189
 190 void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
 191                         size_t len, const void *key,
 192                         unsigned char ivec[16], unsigned char ecount_buf[16],
 193                         unsigned int *num, ctr128_f func)
 194 {
 195         unsigned int n,ctr32;
 196
 197         assert(in && out && key && ecount_buf && num);
 198         assert(*num < 16);
 199
 200         n = *num;
 201
 202         while (n && len) {
 203                 *(out++) = *(in++) ^ ecount_buf[n];
 204                 --len;
 205                 n = (n+1) % 16;
 206         }
 207
 208         ctr32 = GETU32(ivec+12);
 209         while (len>=16) {
 210                 size_t blocks = len/16;
 211                 /*
 212                  * 1<<28 is just a not-so-small yet not-so-large number...
 213                  * Below condition is practically never met, but it has to
 214                  * be checked for code correctness.
 215                  */
 216                 if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
 217                         blocks = (1U<<28);
 218                 /*
 219                  * As (*func) operates on 32-bit counter, caller
 220                  * has to handle overflow. 'if' below detects the
 221                  * overflow, which is then handled by limiting the
 222                  * amount of blocks to the exact overflow point...
 223                  */
 224                 ctr32 += (u32)blocks;
 225                 if (ctr32 < blocks) {
 226                         blocks -= ctr32;
 227                         ctr32   = 0;
 228                 }
 229                 (*func)(in,out,blocks,key,ivec);
 230                 /* (*ctr) does not update ivec, caller does: */
 231                 PUTU32(ivec+12,ctr32);
 232                 /* ... overflow was detected, propogate carry. */
 233                 if (ctr32 == 0) ctr96_inc(ivec);
 234                 blocks *= 16;
 235                 len -= blocks;
 236                 out += blocks;
 237                 in  += blocks;
 238         }
 239         if (len) {
 240                 memset(ecount_buf,0,16);
 241                 (*func)(ecount_buf,ecount_buf,1,key,ivec);
 242                 ++ctr32;
 243                 PUTU32(ivec+12,ctr32);
 244                 if (ctr32 == 0) ctr96_inc(ivec);
 245                 while (len--) {
 246                         out[n] = in[n] ^ ecount_buf[n];
 247                         ++n;
 248                 }
 249         }
 250
 251         *num=n;
 252 }