| Dmitry Shmidt | 8d520ff | 2011-05-09 14:06:53 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * MD5 hash implementation and interface functions |
| 3 | * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * Alternatively, this software may be distributed under the terms of BSD |
| 10 | * license. |
| 11 | * |
| 12 | * See README and COPYING for more details. |
| 13 | */ |
| 14 | |
| 15 | #include "includes.h" |
| 16 | |
| 17 | #include "common.h" |
| 18 | #include "md5.h" |
| 19 | #include "crypto.h" |
| 20 | |
| 21 | |
| 22 | /** |
| 23 | * hmac_md5_vector - HMAC-MD5 over data vector (RFC 2104) |
| 24 | * @key: Key for HMAC operations |
| 25 | * @key_len: Length of the key in bytes |
| 26 | * @num_elem: Number of elements in the data vector |
| 27 | * @addr: Pointers to the data areas |
| 28 | * @len: Lengths of the data blocks |
| 29 | * @mac: Buffer for the hash (16 bytes) |
| 30 | * Returns: 0 on success, -1 on failure |
| 31 | */ |
| 32 | int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem, |
| 33 | const u8 *addr[], const size_t *len, u8 *mac) |
| 34 | { |
| 35 | u8 k_pad[64]; /* padding - key XORd with ipad/opad */ |
| 36 | u8 tk[16]; |
| 37 | const u8 *_addr[6]; |
| 38 | size_t i, _len[6]; |
| 39 | |
| 40 | if (num_elem > 5) { |
| 41 | /* |
| 42 | * Fixed limit on the number of fragments to avoid having to |
| 43 | * allocate memory (which could fail). |
| 44 | */ |
| 45 | return -1; |
| 46 | } |
| 47 | |
| 48 | /* if key is longer than 64 bytes reset it to key = MD5(key) */ |
| 49 | if (key_len > 64) { |
| 50 | if (md5_vector(1, &key, &key_len, tk)) |
| 51 | return -1; |
| 52 | key = tk; |
| 53 | key_len = 16; |
| 54 | } |
| 55 | |
| 56 | /* the HMAC_MD5 transform looks like: |
| 57 | * |
| 58 | * MD5(K XOR opad, MD5(K XOR ipad, text)) |
| 59 | * |
| 60 | * where K is an n byte key |
| 61 | * ipad is the byte 0x36 repeated 64 times |
| 62 | * opad is the byte 0x5c repeated 64 times |
| 63 | * and text is the data being protected */ |
| 64 | |
| 65 | /* start out by storing key in ipad */ |
| 66 | os_memset(k_pad, 0, sizeof(k_pad)); |
| 67 | os_memcpy(k_pad, key, key_len); |
| 68 | |
| 69 | /* XOR key with ipad values */ |
| 70 | for (i = 0; i < 64; i++) |
| 71 | k_pad[i] ^= 0x36; |
| 72 | |
| 73 | /* perform inner MD5 */ |
| 74 | _addr[0] = k_pad; |
| 75 | _len[0] = 64; |
| 76 | for (i = 0; i < num_elem; i++) { |
| 77 | _addr[i + 1] = addr[i]; |
| 78 | _len[i + 1] = len[i]; |
| 79 | } |
| 80 | if (md5_vector(1 + num_elem, _addr, _len, mac)) |
| 81 | return -1; |
| 82 | |
| 83 | os_memset(k_pad, 0, sizeof(k_pad)); |
| 84 | os_memcpy(k_pad, key, key_len); |
| 85 | /* XOR key with opad values */ |
| 86 | for (i = 0; i < 64; i++) |
| 87 | k_pad[i] ^= 0x5c; |
| 88 | |
| 89 | /* perform outer MD5 */ |
| 90 | _addr[0] = k_pad; |
| 91 | _len[0] = 64; |
| 92 | _addr[1] = mac; |
| 93 | _len[1] = MD5_MAC_LEN; |
| 94 | return md5_vector(2, _addr, _len, mac); |
| 95 | } |
| 96 | |
| 97 | |
| 98 | /** |
| 99 | * hmac_md5 - HMAC-MD5 over data buffer (RFC 2104) |
| 100 | * @key: Key for HMAC operations |
| 101 | * @key_len: Length of the key in bytes |
| 102 | * @data: Pointers to the data area |
| 103 | * @data_len: Length of the data area |
| 104 | * @mac: Buffer for the hash (16 bytes) |
| 105 | * Returns: 0 on success, -1 on failure |
| 106 | */ |
| 107 | int hmac_md5(const u8 *key, size_t key_len, const u8 *data, size_t data_len, |
| 108 | u8 *mac) |
| 109 | { |
| 110 | return hmac_md5_vector(key, key_len, 1, &data, &data_len, mac); |
| 111 | } |