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/*
* hmac.c For the sake of illustration we provide the following
* sample code for the implementation of HMAC-MD5 as well
* as some corresponding test vectors (the code is based
* on MD5 code as described in [MD5]).
*
* This library 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.
*
* This library 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
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*
* Copyright 2000,2006 The FreeRADIUS server project
*/
/*
** Function: fr_hmac_md5
*/
RCSID("$Id$")
#ifdef HAVE_OPENSSL_EVP_H
#include <openssl/hmac.h>
#include <openssl/evp.h>
#endif
#include <freeradius-devel/libradius.h>
#include <freeradius-devel/md5.h>
#include <freeradius-devel/openssl3.h>
#if defined(HAVE_OPENSSL_EVP_H) && !defined(WITH_FIPS)
/** Calculate HMAC using OpenSSL's MD5 implementation
*
* @param digest Caller digest to be filled in.
* @param text Pointer to data stream.
* @param text_len length of data stream.
* @param key Pointer to authentication key.
* @param key_len Length of authentication key.
*
*/
void fr_hmac_md5(uint8_t digest[MD5_DIGEST_LENGTH], uint8_t const *text, size_t text_len,
uint8_t const *key, size_t key_len)
{
HMAC_CTX *ctx = HMAC_CTX_new();
unsigned int len = MD5_DIGEST_LENGTH;
#ifdef EVP_MD_CTX_FLAG_NON_FIPS_ALLOW
/* Since MD5 is not allowed by FIPS, explicitly allow it. */
HMAC_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
#endif /* EVP_MD_CTX_FLAG_NON_FIPS_ALLOW */
HMAC_Init_ex(ctx, key, key_len, EVP_md5(), NULL);
HMAC_Update(ctx, text, text_len);
HMAC_Final(ctx, digest, &len);
HMAC_CTX_free(ctx);
}
#else
/** Calculate HMAC using internal MD5 implementation
*
* @param digest Caller digest to be filled in.
* @param text Pointer to data stream.
* @param text_len length of data stream.
* @param key Pointer to authentication key.
* @param key_len Length of authentication key.
*
*/
void fr_hmac_md5(uint8_t digest[MD5_DIGEST_LENGTH], uint8_t const *text, size_t text_len,
uint8_t const *key, size_t key_len)
{
FR_MD5_CTX context;
uint8_t k_ipad[65]; /* inner padding - key XORd with ipad */
uint8_t k_opad[65]; /* outer padding - key XORd with opad */
uint8_t tk[16];
int i;
/* if key is longer than 64 bytes reset it to key=MD5(key) */
if (key_len > 64) {
FR_MD5_CTX tctx;
fr_md5_init(&tctx);
fr_md5_update(&tctx, key, key_len);
fr_md5_final(tk, &tctx);
key = tk;
key_len = 16;
}
/*
* the HMAC_MD5 transform looks like:
*
* MD5(K XOR opad, MD5(K XOR ipad, text))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected
*/
/* start out by storing key in pads */
memset( k_ipad, 0, sizeof(k_ipad));
memset( k_opad, 0, sizeof(k_opad));
memcpy( k_ipad, key, key_len);
memcpy( k_opad, key, key_len);
/* XOR key with ipad and opad values */
for (i = 0; i < 64; i++) {
k_ipad[i] ^= 0x36;
k_opad[i] ^= 0x5c;
}
/*
* perform inner MD5
*/
fr_md5_init(&context); /* init context for 1st
* pass */
fr_md5_update(&context, k_ipad, 64); /* start with inner pad */
fr_md5_update(&context, text, text_len); /* then text of datagram */
fr_md5_final(digest, &context); /* finish up 1st pass */
/*
* perform outer MD5
*/
fr_md5_init(&context); /* init context for 2nd
* pass */
fr_md5_update(&context, k_opad, 64); /* start with outer pad */
fr_md5_update(&context, digest, 16); /* then results of 1st
* hash */
fr_md5_final(digest, &context); /* finish up 2nd pass */
}
#endif /* HAVE_OPENSSL_EVP_H */
/*
Test Vectors (Trailing '\0' of a character string not included in test):
key = 0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
key_len = 16 bytes
data = "Hi There"
data_len = 8 bytes
digest = 0x9294727a3638bb1c13f48ef8158bfc9d
key = "Jefe"
data = "what do ya want for nothing?"
data_len = 28 bytes
digest = 0x750c783e6ab0b503eaa86e310a5db738
key = 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
key_len 16 bytes
data = 0xDDDDDDDDDDDDDDDDDDDD...
..DDDDDDDDDDDDDDDDDDDD...
..DDDDDDDDDDDDDDDDDDDD...
..DDDDDDDDDDDDDDDDDDDD...
..DDDDDDDDDDDDDDDDDDDD
data_len = 50 bytes
digest = 0x56be34521d144c88dbb8c733f0e8b3f6
*/
#ifdef TESTING
/*
* cc -DTESTING -I ../include/ hmac.c md5.c -o hmac
*
* ./hmac Jefe "what do ya want for nothing?"
*/
int main(int argc, char **argv)
{
uint8_t digest[16];
char *key;
int key_len;
char *text;
int text_len;
int i;
key = argv[1];
key_len = strlen(key);
text = argv[2];
text_len = strlen(text);
fr_hmac_md5(digest, text, text_len, key, key_len);
for (i = 0; i < 16; i++) {
printf("%02x", digest[i]);
}
printf("\n");
exit(0);
return 0;
}
#endif
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