xref: /freebsd/contrib/wpa/src/crypto/md5.c (revision 313376588638950ba1e93c403dd8c97bc52fd3a2)
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 
34 	if (num_elem > 5) {
35 		/*
36 		 * Fixed limit on the number of fragments to avoid having to
37 		 * allocate memory (which could fail).
38 		 */
39 		return -1;
40 	}
41 
42         /* if key is longer than 64 bytes reset it to key = MD5(key) */
43         if (key_len > 64) {
44 		if (md5_vector(1, &key, &key_len, tk))
45 			return -1;
46 		key = tk;
47 		key_len = 16;
48         }
49 
50 	/* the HMAC_MD5 transform looks like:
51 	 *
52 	 * MD5(K XOR opad, MD5(K XOR ipad, text))
53 	 *
54 	 * where K is an n byte key
55 	 * ipad is the byte 0x36 repeated 64 times
56 	 * opad is the byte 0x5c repeated 64 times
57 	 * and text is the data being protected */
58 
59 	/* start out by storing key in ipad */
60 	os_memset(k_pad, 0, sizeof(k_pad));
61 	os_memcpy(k_pad, key, key_len);
62 
63 	/* XOR key with ipad values */
64 	for (i = 0; i < 64; i++)
65 		k_pad[i] ^= 0x36;
66 
67 	/* perform inner MD5 */
68 	_addr[0] = k_pad;
69 	_len[0] = 64;
70 	for (i = 0; i < num_elem; i++) {
71 		_addr[i + 1] = addr[i];
72 		_len[i + 1] = len[i];
73 	}
74 	if (md5_vector(1 + num_elem, _addr, _len, mac))
75 		return -1;
76 
77 	os_memset(k_pad, 0, sizeof(k_pad));
78 	os_memcpy(k_pad, key, key_len);
79 	/* XOR key with opad values */
80 	for (i = 0; i < 64; i++)
81 		k_pad[i] ^= 0x5c;
82 
83 	/* perform outer MD5 */
84 	_addr[0] = k_pad;
85 	_len[0] = 64;
86 	_addr[1] = mac;
87 	_len[1] = MD5_MAC_LEN;
88 	return md5_vector(2, _addr, _len, mac);
89 }
90 
91 
92 /**
93  * hmac_md5 - HMAC-MD5 over data buffer (RFC 2104)
94  * @key: Key for HMAC operations
95  * @key_len: Length of the key in bytes
96  * @data: Pointers to the data area
97  * @data_len: Length of the data area
98  * @mac: Buffer for the hash (16 bytes)
99  * Returns: 0 on success, -1 on failure
100  */
101 int hmac_md5(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
102 	      u8 *mac)
103 {
104 	return hmac_md5_vector(key, key_len, 1, &data, &data_len, mac);
105 }
106