d93aa10bac
For consistency and safety, change the CMC and HSH functions to accept signed lengths and handle negative values as errors. Also, change the input data type to void * to not require casting in the caller.
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2019
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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Support for AES128 and AES256 CMAC in Nettle.
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*/
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#include "config.h"
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#include "sysincl.h"
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#include <nettle/cmac.h>
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#include "cmac.h"
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#include "memory.h"
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struct CMC_Instance_Record {
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int key_length;
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union {
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struct cmac_aes128_ctx aes128;
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struct cmac_aes256_ctx aes256;
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} context;
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};
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/* ================================================== */
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int
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CMC_GetKeyLength(CMC_Algorithm algorithm)
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{
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if (algorithm == CMC_AES128)
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return AES128_KEY_SIZE;
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else if (algorithm == CMC_AES256)
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return AES256_KEY_SIZE;
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return 0;
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}
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/* ================================================== */
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CMC_Instance
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CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key, int length)
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{
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CMC_Instance inst;
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if (length <= 0 || length != CMC_GetKeyLength(algorithm))
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return NULL;
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inst = MallocNew(struct CMC_Instance_Record);
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inst->key_length = length;
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switch (length) {
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case AES128_KEY_SIZE:
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cmac_aes128_set_key(&inst->context.aes128, key);
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break;
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case AES256_KEY_SIZE:
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cmac_aes256_set_key(&inst->context.aes256, key);
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break;
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default:
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assert(0);
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}
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return inst;
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}
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/* ================================================== */
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int
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CMC_Hash(CMC_Instance inst, const void *in, int in_len, unsigned char *out, int out_len)
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{
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if (in_len < 0 || out_len < 0)
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return 0;
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if (out_len > CMAC128_DIGEST_SIZE)
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out_len = CMAC128_DIGEST_SIZE;
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switch (inst->key_length) {
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case AES128_KEY_SIZE:
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cmac_aes128_update(&inst->context.aes128, in_len, in);
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cmac_aes128_digest(&inst->context.aes128, out_len, out);
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break;
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case AES256_KEY_SIZE:
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cmac_aes256_update(&inst->context.aes256, in_len, in);
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cmac_aes256_digest(&inst->context.aes256, out_len, out);
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break;
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default:
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assert(0);
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}
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return out_len;
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}
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/* ================================================== */
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void
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CMC_DestroyInstance(CMC_Instance inst)
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{
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Free(inst);
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}
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