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/* mac-gmac.c - GMAC glue for MAC API
* Copyright (C) 2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser general Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "g10lib.h"
#include "cipher.h"
#include "./mac-internal.h"
static int
map_mac_algo_to_cipher (int mac_algo)
{
switch (mac_algo)
{
default:
return GCRY_CIPHER_NONE;
case GCRY_MAC_GMAC_AES:
return GCRY_CIPHER_AES;
case GCRY_MAC_GMAC_CAMELLIA:
return GCRY_CIPHER_CAMELLIA128;
case GCRY_MAC_GMAC_TWOFISH:
return GCRY_CIPHER_TWOFISH;
case GCRY_MAC_GMAC_SERPENT:
return GCRY_CIPHER_SERPENT128;
case GCRY_MAC_GMAC_SEED:
return GCRY_CIPHER_SEED;
}
}
static gcry_err_code_t
gmac_open (gcry_mac_hd_t h)
{
gcry_err_code_t err;
gcry_cipher_hd_t hd;
int secure = (h->magic == CTX_MAC_MAGIC_SECURE);
int cipher_algo;
unsigned int flags;
cipher_algo = map_mac_algo_to_cipher (h->spec->algo);
flags = (secure ? GCRY_CIPHER_SECURE : 0);
err = _gcry_cipher_open_internal (&hd, cipher_algo, GCRY_CIPHER_MODE_GCM,
flags);
if (err)
return err;
h->u.gmac.cipher_algo = cipher_algo;
h->u.gmac.ctx = hd;
return 0;
}
static void
gmac_close (gcry_mac_hd_t h)
{
_gcry_cipher_close (h->u.gmac.ctx);
h->u.gmac.ctx = NULL;
}
static gcry_err_code_t
gmac_setkey (gcry_mac_hd_t h, const unsigned char *key, size_t keylen)
{
return _gcry_cipher_setkey (h->u.gmac.ctx, key, keylen);
}
static gcry_err_code_t
gmac_setiv (gcry_mac_hd_t h, const unsigned char *iv, size_t ivlen)
{
return _gcry_cipher_setiv (h->u.gmac.ctx, iv, ivlen);
}
static gcry_err_code_t
gmac_reset (gcry_mac_hd_t h)
{
return _gcry_cipher_reset (h->u.gmac.ctx);
}
static gcry_err_code_t
gmac_write (gcry_mac_hd_t h, const unsigned char *buf, size_t buflen)
{
return _gcry_cipher_authenticate (h->u.gmac.ctx, buf, buflen);
}
static gcry_err_code_t
gmac_read (gcry_mac_hd_t h, unsigned char *outbuf, size_t * outlen)
{
if (*outlen > GCRY_GCM_BLOCK_LEN)
*outlen = GCRY_GCM_BLOCK_LEN;
return _gcry_cipher_gettag (h->u.gmac.ctx, outbuf, *outlen);
}
static gcry_err_code_t
gmac_verify (gcry_mac_hd_t h, const unsigned char *buf, size_t buflen)
{
return _gcry_cipher_checktag (h->u.gmac.ctx, buf, buflen);
}
static unsigned int
gmac_get_maclen (int algo)
{
(void)algo;
return GCRY_GCM_BLOCK_LEN;
}
static unsigned int
gmac_get_keylen (int algo)
{
return _gcry_cipher_get_algo_keylen (map_mac_algo_to_cipher (algo));
}
static gcry_mac_spec_ops_t gmac_ops = {
gmac_open,
gmac_close,
gmac_setkey,
gmac_setiv,
gmac_reset,
gmac_write,
gmac_read,
gmac_verify,
gmac_get_maclen,
gmac_get_keylen,
NULL,
NULL
};
#if USE_AES
gcry_mac_spec_t _gcry_mac_type_spec_gmac_aes = {
GCRY_MAC_GMAC_AES, {0, 1}, "GMAC_AES",
&gmac_ops
};
#endif
#if USE_TWOFISH
gcry_mac_spec_t _gcry_mac_type_spec_gmac_twofish = {
GCRY_MAC_GMAC_TWOFISH, {0, 0}, "GMAC_TWOFISH",
&gmac_ops
};
#endif
#if USE_SERPENT
gcry_mac_spec_t _gcry_mac_type_spec_gmac_serpent = {
GCRY_MAC_GMAC_SERPENT, {0, 0}, "GMAC_SERPENT",
&gmac_ops
};
#endif
#if USE_SEED
gcry_mac_spec_t _gcry_mac_type_spec_gmac_seed = {
GCRY_MAC_GMAC_SEED, {0, 0}, "GMAC_SEED",
&gmac_ops
};
#endif
#if USE_CAMELLIA
gcry_mac_spec_t _gcry_mac_type_spec_gmac_camellia = {
GCRY_MAC_GMAC_CAMELLIA, {0, 0}, "GMAC_CAMELLIA",
&gmac_ops
};
#endif