release/src-rt-6.x.4708/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 /*
  63  * NOTE: the IV/counter CTR mode is big-endian.  The code itself is
  64  * endian-neutral.
  65  */
  66
  67 /* increment counter (128-bit int) by 1 */
  68 static void ctr128_inc(unsigned char *counter)
  69 {
  70     u32 n = 16;
  71     u8 c;
  72
  73     do {
  74         --n;
  75         c = counter[n];
  76         ++c;
  77         counter[n] = c;
  78         if (c)
  79             return;
  80     } while (n);
  81 }
  82
  83 #if !defined(OPENSSL_SMALL_FOOTPRINT)
  84 static void ctr128_inc_aligned(unsigned char *counter)
  85 {
  86     size_t *data, c, n;
  87     const union {
  88         long one;
  89         char little;
  90     } is_endian = {
  91         1
  92     };
  93
  94     if (is_endian.little) {
  95         ctr128_inc(counter);
  96         return;
  97     }
  98
  99     data = (size_t *)counter;
 100     n = 16 / sizeof(size_t);
 101     do {
 102         --n;
 103         c = data[n];
 104         ++c;
 105         data[n] = c;
 106         if (c)
 107             return;
 108     } while (n);
 109 }
 110 #endif
 111
 112 /*
 113  * The input encrypted as though 128bit counter mode is being used.  The
 114  * extra state information to record how much of the 128bit block we have
 115  * used is contained in *num, and the encrypted counter is kept in
 116  * ecount_buf.  Both *num and ecount_buf must be initialised with zeros
 117  * before the first call to CRYPTO_ctr128_encrypt(). This algorithm assumes
 118  * that the counter is in the x lower bits of the IV (ivec), and that the
 119  * application has full control over overflow and the rest of the IV.  This
 120  * implementation takes NO responsability for checking that the counter
 121  * doesn't overflow into the rest of the IV when incremented.
 122  */
 123 void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
 124                            size_t len, const void *key,
 125                            unsigned char ivec[16],
 126                            unsigned char ecount_buf[16], unsigned int *num,
 127                            block128_f block)
 128 {
 129     unsigned int n;
 130     size_t l = 0;
 131
 132     assert(in && out && key && ecount_buf && num);
 133     assert(*num < 16);
 134
 135     n = *num;
 136
 137 #if !defined(OPENSSL_SMALL_FOOTPRINT)
 138     if (16 % sizeof(size_t) == 0) { /* always true actually */
 139         do {
 140             while (n && len) {
 141                 *(out++) = *(in++) ^ ecount_buf[n];
 142                 --len;
 143                 n = (n + 1) % 16;
 144             }
 145
 146 # if defined(STRICT_ALIGNMENT)
 147             if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=
 148                 0)
 149                 break;
 150 # endif
 151             while (len >= 16) {
 152                 (*block) (ivec, ecount_buf, key);
 153                 ctr128_inc_aligned(ivec);
 154                 for (; n < 16; n += sizeof(size_t))
 155                     *(size_t *)(out + n) =
 156                         *(size_t *)(in + n) ^ *(size_t *)(ecount_buf + n);
 157                 len -= 16;
 158                 out += 16;
 159                 in += 16;
 160                 n = 0;
 161             }
 162             if (len) {
 163                 (*block) (ivec, ecount_buf, key);
 164                 ctr128_inc_aligned(ivec);
 165                 while (len--) {
 166                     out[n] = in[n] ^ ecount_buf[n];
 167                     ++n;
 168                 }
 169             }
 170             *num = n;
 171             return;
 172         } while (0);
 173     }
 174     /* the rest would be commonly eliminated by x86* compiler */
 175 #endif
 176     while (l < len) {
 177         if (n == 0) {
 178             (*block) (ivec, ecount_buf, key);
 179             ctr128_inc(ivec);
 180         }
 181         out[l] = in[l] ^ ecount_buf[n];
 182         ++l;
 183         n = (n + 1) % 16;
 184     }
 185
 186     *num = n;
 187 }
 188
 189 /* increment upper 96 bits of 128-bit counter by 1 */
 190 static void ctr96_inc(unsigned char *counter)
 191 {
 192     u32 n = 12;
 193     u8 c;
 194
 195     do {
 196         --n;
 197         c = counter[n];
 198         ++c;
 199         counter[n] = c;
 200         if (c)
 201             return;
 202     } while (n);
 203 }
 204
 205 void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
 206                                  size_t len, const void *key,
 207                                  unsigned char ivec[16],
 208                                  unsigned char ecount_buf[16],
 209                                  unsigned int *num, ctr128_f func)
 210 {
 211     unsigned int n, ctr32;
 212
 213     assert(in && out && key && ecount_buf && num);
 214     assert(*num < 16);
 215
 216     n = *num;
 217
 218     while (n && len) {
 219         *(out++) = *(in++) ^ ecount_buf[n];
 220         --len;
 221         n = (n + 1) % 16;
 222     }
 223
 224     ctr32 = GETU32(ivec + 12);
 225     while (len >= 16) {
 226         size_t blocks = len / 16;
 227         /*
 228          * 1<<28 is just a not-so-small yet not-so-large number...
 229          * Below condition is practically never met, but it has to
 230          * be checked for code correctness.
 231          */
 232         if (sizeof(size_t) > sizeof(unsigned int) && blocks > (1U << 28))
 233             blocks = (1U << 28);
 234         /*
 235          * As (*func) operates on 32-bit counter, caller
 236          * has to handle overflow. 'if' below detects the
 237          * overflow, which is then handled by limiting the
 238          * amount of blocks to the exact overflow point...
 239          */
 240         ctr32 += (u32)blocks;
 241         if (ctr32 < blocks) {
 242             blocks -= ctr32;
 243             ctr32 = 0;
 244         }
 245         (*func) (in, out, blocks, key, ivec);
 246         /* (*ctr) does not update ivec, caller does: */
 247         PUTU32(ivec + 12, ctr32);
 248         /* ... overflow was detected, propogate carry. */
 249         if (ctr32 == 0)
 250             ctr96_inc(ivec);
 251         blocks *= 16;
 252         len -= blocks;
 253         out += blocks;
 254         in += blocks;
 255     }
 256     if (len) {
 257         memset(ecount_buf, 0, 16);
 258         (*func) (ecount_buf, ecount_buf, 1, key, ivec);
 259         ++ctr32;
 260         PUTU32(ivec + 12, ctr32);
 261         if (ctr32 == 0)
 262             ctr96_inc(ivec);
 263         while (len--) {
 264             out[n] = in[n] ^ ecount_buf[n];
 265             ++n;
 266         }
 267     }
 268
 269     *num = n;
 270 }