1 /*
2 * MD5 hash implementation and interface functions (non-FIPS allowed cases)
3 * Copyright (c) 2003-2009, 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_non_fips_allow - 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 */
hmac_md5_vector_non_fips_allow(const u8 * key,size_t key_len,size_t num_elem,const u8 * addr[],const size_t * len,u8 * mac)32 int hmac_md5_vector_non_fips_allow(const u8 *key, size_t key_len,
33 size_t num_elem, const u8 *addr[],
34 const size_t *len, u8 *mac)
35 {
36 u8 k_pad[64]; /* padding - key XORd with ipad/opad */
37 u8 tk[16];
38 const u8 *_addr[6];
39 size_t i, _len[6];
40
41 if (num_elem > 5) {
42 /*
43 * Fixed limit on the number of fragments to avoid having to
44 * allocate memory (which could fail).
45 */
46 return -1;
47 }
48
49 /* if key is longer than 64 bytes reset it to key = MD5(key) */
50 if (key_len > 64) {
51 if (md5_vector_non_fips_allow(1, &key, &key_len, tk))
52 return -1;
53 key = tk;
54 key_len = 16;
55 }
56
57 /* the HMAC_MD5 transform looks like:
58 *
59 * MD5(K XOR opad, MD5(K XOR ipad, text))
60 *
61 * where K is an n byte key
62 * ipad is the byte 0x36 repeated 64 times
63 * opad is the byte 0x5c repeated 64 times
64 * and text is the data being protected */
65
66 /* start out by storing key in ipad */
67 os_memset(k_pad, 0, sizeof(k_pad));
68 os_memcpy(k_pad, key, key_len);
69
70 /* XOR key with ipad values */
71 for (i = 0; i < 64; i++)
72 k_pad[i] ^= 0x36;
73
74 /* perform inner MD5 */
75 _addr[0] = k_pad;
76 _len[0] = 64;
77 for (i = 0; i < num_elem; i++) {
78 _addr[i + 1] = addr[i];
79 _len[i + 1] = len[i];
80 }
81 if (md5_vector_non_fips_allow(1 + num_elem, _addr, _len, mac))
82 return -1;
83
84 os_memset(k_pad, 0, sizeof(k_pad));
85 os_memcpy(k_pad, key, key_len);
86 /* XOR key with opad values */
87 for (i = 0; i < 64; i++)
88 k_pad[i] ^= 0x5c;
89
90 /* perform outer MD5 */
91 _addr[0] = k_pad;
92 _len[0] = 64;
93 _addr[1] = mac;
94 _len[1] = MD5_MAC_LEN;
95 return md5_vector_non_fips_allow(2, _addr, _len, mac);
96 }
97
98
99 /**
100 * hmac_md5_non_fips_allow - HMAC-MD5 over data buffer (RFC 2104)
101 * @key: Key for HMAC operations
102 * @key_len: Length of the key in bytes
103 * @data: Pointers to the data area
104 * @data_len: Length of the data area
105 * @mac: Buffer for the hash (16 bytes)
106 * Returns: 0 on success, -1 on failure
107 */
hmac_md5_non_fips_allow(const u8 * key,size_t key_len,const u8 * data,size_t data_len,u8 * mac)108 int hmac_md5_non_fips_allow(const u8 *key, size_t key_len, const u8 *data,
109 size_t data_len, u8 *mac)
110 {
111 return hmac_md5_vector_non_fips_allow(key, key_len, 1, &data,
112 &data_len, mac);
113 }
114