1/* 2 * dhcpcd - DHCP client daemon 3 * Copyright (c) 2006-2015 Roy Marples <roy@marples.name> 4 * All rights reserved 5 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <inttypes.h> 29#include <string.h> 30 31#include "crypt.h" 32 33#include "../config.h" 34#ifdef HAVE_MD5_H 35# ifndef DEPGEN 36# include <md5.h> 37# endif 38#else 39# include "md5.h" 40#endif 41 42#define HMAC_PAD_LEN 64 43#define IPAD 0x36 44#define OPAD 0x5C 45 46/* hmac_md5 as per RFC3118 */ 47void 48hmac_md5(const uint8_t *text, size_t text_len, 49 const uint8_t *key, size_t key_len, 50 uint8_t *digest) 51{ 52 uint8_t k_ipad[HMAC_PAD_LEN], k_opad[HMAC_PAD_LEN]; 53 uint8_t tk[MD5_DIGEST_LENGTH]; 54 int i; 55 MD5_CTX context; 56 57 /* Ensure key is no bigger than HMAC_PAD_LEN */ 58 if (key_len > HMAC_PAD_LEN) { 59 MD5Init(&context); 60 MD5Update(&context, key, (unsigned int)key_len); 61 MD5Final(tk, &context); 62 key = tk; 63 key_len = MD5_DIGEST_LENGTH; 64 } 65 66 /* store key in pads */ 67 memcpy(k_ipad, key, key_len); 68 memcpy(k_opad, key, key_len); 69 memset(k_ipad + key_len, 0, sizeof(k_ipad) - key_len); 70 memset(k_opad + key_len, 0, sizeof(k_opad) - key_len); 71 72 /* XOR key with ipad and opad values */ 73 for (i = 0; i < HMAC_PAD_LEN; i++) { 74 k_ipad[i] ^= IPAD; 75 k_opad[i] ^= OPAD; 76 } 77 78 /* inner MD5 */ 79 MD5Init(&context); 80 MD5Update(&context, k_ipad, HMAC_PAD_LEN); 81 MD5Update(&context, text, (unsigned int)text_len); 82 MD5Final(digest, &context); 83 84 /* outer MD5 */ 85 MD5Init(&context); 86 MD5Update(&context, k_opad, HMAC_PAD_LEN); 87 MD5Update(&context, digest, MD5_DIGEST_LENGTH); 88 MD5Final(digest, &context); 89} 90