/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2014 Roy Marples <roy@marples.name>
* All rights reserved
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <inttypes.h>
#include <string.h>
#include "crypt.h"
#ifdef HAVE_MD5_H
#include <md5.h>
#else
#include "md5.h"
#endif
#define HMAC_PAD_LEN 64
#define IPAD 0x36
#define OPAD 0x5C
/* hmac_md5 as per RFC3118 */
void
hmac_md5(const uint8_t *text, int text_len,
const uint8_t *key, int key_len,
uint8_t *digest)
{
uint8_t k_ipad[HMAC_PAD_LEN], k_opad[HMAC_PAD_LEN];
uint8_t tk[MD5_DIGEST_LENGTH];
int i;
MD5_CTX context;
/* Ensure key is no bigger than HMAC_PAD_LEN */
if (key_len > HMAC_PAD_LEN) {
MD5Init(&context);
MD5Update(&context, key, key_len);
MD5Final(tk, &context);
key = tk;
key_len = MD5_DIGEST_LENGTH;
}
/* store key in pads */
memcpy(k_ipad, key, key_len);
memcpy(k_opad, key, key_len);
memset(k_ipad + key_len, 0, sizeof(k_ipad) - key_len);
memset(k_opad + key_len, 0, sizeof(k_opad) - key_len);
/* XOR key with ipad and opad values */
for (i = 0; i < HMAC_PAD_LEN; i++) {
k_ipad[i] ^= IPAD;
k_opad[i] ^= OPAD;
}
/* inner MD5 */
MD5Init(&context);
MD5Update(&context, k_ipad, HMAC_PAD_LEN);
MD5Update(&context, text, text_len);
MD5Final(digest, &context);
/* outer MD5 */
MD5Init(&context);
MD5Update(&context, k_opad, HMAC_PAD_LEN);
MD5Update(&context, digest, MD5_DIGEST_LENGTH);
MD5Final(digest, &context);
}
