1 /* 2 * MD5 hash implementation and interface functions 3 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 11 #include "common.h" 12 #include "md5.h" 13 #include "crypto.h" 14 15 16 /** 17 * hmac_md5_vector - HMAC-MD5 over data vector (RFC 2104) 18 * @key: Key for HMAC operations 19 * @key_len: Length of the key in bytes 20 * @num_elem: Number of elements in the data vector 21 * @addr: Pointers to the data areas 22 * @len: Lengths of the data blocks 23 * @mac: Buffer for the hash (16 bytes) 24 * Returns: 0 on success, -1 on failure 25 */ 26 int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem, 27 const u8 *addr[], const size_t *len, u8 *mac) 28 { 29 u8 k_pad[64]; /* padding - key XORd with ipad/opad */ 30 u8 tk[16]; 31 const u8 *_addr[6]; 32 size_t i, _len[6]; 33 int res; 34 35 if (num_elem > 5) { 36 /* 37 * Fixed limit on the number of fragments to avoid having to 38 * allocate memory (which could fail). 39 */ 40 return -1; 41 } 42 43 /* if key is longer than 64 bytes reset it to key = MD5(key) */ 44 if (key_len > 64) { 45 if (md5_vector(1, &key, &key_len, tk)) 46 return -1; 47 key = tk; 48 key_len = 16; 49 } 50 51 /* the HMAC_MD5 transform looks like: 52 * 53 * MD5(K XOR opad, MD5(K XOR ipad, text)) 54 * 55 * where K is an n byte key 56 * ipad is the byte 0x36 repeated 64 times 57 * opad is the byte 0x5c repeated 64 times 58 * and text is the data being protected */ 59 60 /* start out by storing key in ipad */ 61 os_memset(k_pad, 0, sizeof(k_pad)); 62 os_memcpy(k_pad, key, key_len); 63 64 /* XOR key with ipad values */ 65 for (i = 0; i < 64; i++) 66 k_pad[i] ^= 0x36; 67 68 /* perform inner MD5 */ 69 _addr[0] = k_pad; 70 _len[0] = 64; 71 for (i = 0; i < num_elem; i++) { 72 _addr[i + 1] = addr[i]; 73 _len[i + 1] = len[i]; 74 } 75 if (md5_vector(1 + num_elem, _addr, _len, mac)) 76 return -1; 77 78 os_memset(k_pad, 0, sizeof(k_pad)); 79 os_memcpy(k_pad, key, key_len); 80 /* XOR key with opad values */ 81 for (i = 0; i < 64; i++) 82 k_pad[i] ^= 0x5c; 83 84 /* perform outer MD5 */ 85 _addr[0] = k_pad; 86 _len[0] = 64; 87 _addr[1] = mac; 88 _len[1] = MD5_MAC_LEN; 89 res = md5_vector(2, _addr, _len, mac); 90 os_memset(k_pad, 0, sizeof(k_pad)); 91 os_memset(tk, 0, sizeof(tk)); 92 return res; 93 } 94 95 96 /** 97 * hmac_md5 - HMAC-MD5 over data buffer (RFC 2104) 98 * @key: Key for HMAC operations 99 * @key_len: Length of the key in bytes 100 * @data: Pointers to the data area 101 * @data_len: Length of the data area 102 * @mac: Buffer for the hash (16 bytes) 103 * Returns: 0 on success, -1 on failure 104 */ 105 int hmac_md5(const u8 *key, size_t key_len, const u8 *data, size_t data_len, 106 u8 *mac) 107 { 108 return hmac_md5_vector(key, key_len, 1, &data, &data_len, mac); 109 } 110