release/src/router/nettle/umac32.c

   1 /* umac32.c
   2  */
   3
   4 /* nettle, low-level cryptographics library
   5  *
   6  * Copyright (C) 2013 Niels Möller
   7  *
   8  * The nettle library is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or (at your
  11  * option) any later version.
  12  *
  13  * The nettle library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16  * License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  20  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  21  * MA 02111-1301, USA.
  22  */
  23
  24 #if HAVE_CONFIG_H
  25 # include "config.h"
  26 #endif
  27
  28 #include <assert.h>
  29 #include <string.h>
  30
  31 #include "umac.h"
  32
  33 #include "macros.h"
  34
  35 void
  36 umac32_set_key (struct umac32_ctx *ctx, const uint8_t *key)
  37 {
  38   _umac_set_key (ctx->l1_key, ctx->l2_key, ctx->l3_key1, ctx->l3_key2,
  39                  &ctx->pdf_key, key, 1);
  40
  41   /* Clear nonce */
  42   memset (ctx->nonce, 0, sizeof(ctx->nonce));
  43   ctx->nonce_low = 0;
  44   ctx->nonce_length = sizeof(ctx->nonce);
  45
  46   /* Initialize buffer */
  47   ctx->count = ctx->index = 0;
  48 }
  49
  50 void
  51 umac32_set_nonce (struct umac32_ctx *ctx,
  52                   unsigned nonce_length, const uint8_t *nonce)
  53 {
  54   assert (nonce_length > 0);
  55   assert (nonce_length <= AES_BLOCK_SIZE);
  56
  57   memcpy (ctx->nonce, nonce, nonce_length);
  58   memset (ctx->nonce + nonce_length, 0, AES_BLOCK_SIZE - nonce_length);
  59
  60   ctx->nonce_low = ctx->nonce[nonce_length - 1] & 3;
  61   ctx->nonce[nonce_length - 1] &= ~3;
  62   ctx->nonce_length = nonce_length;
  63 }
  64
  65 #define UMAC32_BLOCK(ctx, block) do {                                   \
  66     uint64_t __umac32_y                                                 \
  67       = _umac_nh (ctx->l1_key, UMAC_DATA_SIZE, block)                   \
  68       + 8*UMAC_DATA_SIZE ;                                              \
  69     _umac_l2 (ctx->l2_key, ctx->l2_state, 1, ctx->count++, &__umac32_y); \
  70   } while (0)
  71
  72 void
  73 umac32_update (struct umac32_ctx *ctx,
  74                unsigned length, const uint8_t *data)
  75 {
  76   MD_UPDATE (ctx, length, data, UMAC32_BLOCK, (void)0);
  77 }
  78
  79
  80 void
  81 umac32_digest (struct umac32_ctx *ctx,
  82                unsigned length, uint8_t *digest)
  83 {
  84   uint32_t pad;
  85
  86   assert (length > 0);
  87   assert (length <= 4);
  88
  89   if (ctx->index > 0 || ctx->count == 0)
  90     {
  91       /* Zero pad to multiple of 32 */
  92       uint64_t y;
  93       unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
  94       memset (ctx->block + ctx->index, 0, pad);
  95
  96       y = _umac_nh (ctx->l1_key, ctx->index + pad, ctx->block)
  97         + 8 * ctx->index;
  98       _umac_l2 (ctx->l2_key, ctx->l2_state, 1, ctx->count++, &y);
  99     }
 100   assert (ctx->count > 0);
 101   if ( !(ctx->nonce_low & _UMAC_NONCE_CACHED))
 102     {
 103       aes_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
 104                    (uint8_t *) ctx->pad_cache, ctx->nonce);
 105       ctx->nonce_low |= _UMAC_NONCE_CACHED;
 106     }
 107
 108   pad = ctx->pad_cache[ctx->nonce_low & 3];
 109
 110   /* Increment nonce */
 111   ctx->nonce_low++;
 112   if ( !(ctx->nonce_low & 3))
 113     {
 114       unsigned i = ctx->nonce_length - 1;
 115
 116       ctx->nonce_low = 0;
 117       ctx->nonce[i] += 4;
 118
 119       if (ctx->nonce[i] == 0 && i > 0)
 120         INCREMENT (i, ctx->nonce);
 121     }
 122
 123   _umac_l2_final (ctx->l2_key, ctx->l2_state, 1, ctx->count);
 124   pad ^= ctx->l3_key2[0] ^ _umac_l3 (ctx->l3_key1, ctx->l2_state);
 125   memcpy (digest, &pad, length);
 126
 127   /* Reinitialize */
 128   ctx->count = ctx->index = 0;
 129 }