release/src/router/nettle/umac96.c

   1 /* umac96.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 umac96_set_key (struct umac96_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, 3);
  40
  41   /* Clear nonce */
  42   memset (ctx->nonce, 0, sizeof(ctx->nonce));
  43   ctx->nonce_length = sizeof(ctx->nonce);
  44
  45   /* Initialize buffer */
  46   ctx->count = ctx->index = 0;
  47 }
  48
  49 void
  50 umac96_set_nonce (struct umac96_ctx *ctx,
  51                   unsigned nonce_length, const uint8_t *nonce)
  52 {
  53   assert (nonce_length > 0);
  54   assert (nonce_length <= AES_BLOCK_SIZE);
  55
  56   memcpy (ctx->nonce, nonce, nonce_length);
  57   memset (ctx->nonce + nonce_length, 0, AES_BLOCK_SIZE - nonce_length);
  58
  59   ctx->nonce_length = nonce_length;
  60 }
  61
  62 #define UMAC96_BLOCK(ctx, block) do {                                   \
  63     uint64_t __umac96_y[3];                                             \
  64     _umac_nh_n (__umac96_y, 3, ctx->l1_key, UMAC_DATA_SIZE, block);     \
  65     __umac96_y[0] += 8*UMAC_DATA_SIZE;                                  \
  66     __umac96_y[1] += 8*UMAC_DATA_SIZE;                                  \
  67     __umac96_y[2] += 8*UMAC_DATA_SIZE;                                  \
  68     _umac_l2 (ctx->l2_key, ctx->l2_state, 3, ctx->count++, __umac96_y); \
  69   } while (0)
  70
  71 void
  72 umac96_update (struct umac96_ctx *ctx,
  73                unsigned length, const uint8_t *data)
  74 {
  75   MD_UPDATE (ctx, length, data, UMAC96_BLOCK, (void)0);
  76 }
  77
  78
  79 void
  80 umac96_digest (struct umac96_ctx *ctx,
  81                unsigned length, uint8_t *digest)
  82 {
  83   uint32_t tag[4];
  84   unsigned i;
  85
  86   assert (length > 0);
  87   assert (length <= 12);
  88
  89   if (ctx->index > 0 || ctx->count == 0)
  90     {
  91       /* Zero pad to multiple of 32 */
  92       uint64_t y[3];
  93       unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
  94       memset (ctx->block + ctx->index, 0, pad);
  95
  96       _umac_nh_n (y, 3, ctx->l1_key, ctx->index + pad, ctx->block);
  97       y[0] += 8 * ctx->index;
  98       y[1] += 8 * ctx->index;
  99       y[2] += 8 * ctx->index;
 100       _umac_l2 (ctx->l2_key, ctx->l2_state, 3, ctx->count++, y);
 101     }
 102   assert (ctx->count > 0);
 103
 104   aes_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
 105                (uint8_t *) tag, ctx->nonce);
 106
 107   INCREMENT (ctx->nonce_length, ctx->nonce);
 108
 109   _umac_l2_final (ctx->l2_key, ctx->l2_state, 3, ctx->count);
 110   for (i = 0; i < 3; i++)
 111     tag[i] ^= ctx->l3_key2[i] ^ _umac_l3 (ctx->l3_key1 + 8*i,
 112                                           ctx->l2_state + 2*i);
 113
 114   memcpy (digest, tag, length);
 115
 116   /* Reinitialize */
 117   ctx->count = ctx->index = 0;
 118 }