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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Miroslav Lichvar 2019
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
Support for AES128 and AES256 CMAC in Nettle.
*/
#include "config.h"
#include "sysincl.h"
#include <nettle/cmac.h>
#include "cmac.h"
#include "memory.h"
struct CMC_Instance_Record {
int key_length;
union {
struct cmac_aes128_ctx aes128;
struct cmac_aes256_ctx aes256;
} context;
};
/* ================================================== */
int
CMC_GetKeyLength(CMC_Algorithm algorithm)
{
if (algorithm == CMC_AES128)
return AES128_KEY_SIZE;
else if (algorithm == CMC_AES256)
return AES256_KEY_SIZE;
return 0;
}
/* ================================================== */
CMC_Instance
CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key, int length)
{
CMC_Instance inst;
if (length <= 0 || length != CMC_GetKeyLength(algorithm))
return NULL;
inst = MallocNew(struct CMC_Instance_Record);
inst->key_length = length;
switch (length) {
case AES128_KEY_SIZE:
cmac_aes128_set_key(&inst->context.aes128, key);
break;
case AES256_KEY_SIZE:
cmac_aes256_set_key(&inst->context.aes256, key);
break;
default:
assert(0);
}
return inst;
}
/* ================================================== */
int
CMC_Hash(CMC_Instance inst, const void *in, int in_len, unsigned char *out, int out_len)
{
if (in_len < 0 || out_len < 0)
return 0;
if (out_len > CMAC128_DIGEST_SIZE)
out_len = CMAC128_DIGEST_SIZE;
switch (inst->key_length) {
case AES128_KEY_SIZE:
cmac_aes128_update(&inst->context.aes128, in_len, in);
cmac_aes128_digest(&inst->context.aes128, out_len, out);
break;
case AES256_KEY_SIZE:
cmac_aes256_update(&inst->context.aes256, in_len, in);
cmac_aes256_digest(&inst->context.aes256, out_len, out);
break;
default:
assert(0);
}
return out_len;
}
/* ================================================== */
void
CMC_DestroyInstance(CMC_Instance inst)
{
Free(inst);
}
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