1/*
2 * SHA1 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 "sha1.h"
13#include "crypto.h"
14
15
16/**
17 * hmac_sha1_vector - HMAC-SHA1 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 (20 bytes)
24 * Returns: 0 on success, -1 on failure
25 */
26int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
27		     const u8 *addr[], const size_t *len, u8 *mac)
28{
29	unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
30	unsigned char tk[20];
31	const u8 *_addr[6];
32	size_t _len[6], i;
33	int ret;
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 = SHA1(key) */
44        if (key_len > 64) {
45		if (sha1_vector(1, &key, &key_len, tk))
46			return -1;
47		key = tk;
48		key_len = 20;
49        }
50
51	/* the HMAC_SHA1 transform looks like:
52	 *
53	 * SHA1(K XOR opad, SHA1(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	/* XOR key with ipad values */
64	for (i = 0; i < 64; i++)
65		k_pad[i] ^= 0x36;
66
67	/* perform inner SHA1 */
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 (sha1_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 SHA1 */
84	_addr[0] = k_pad;
85	_len[0] = 64;
86	_addr[1] = mac;
87	_len[1] = SHA1_MAC_LEN;
88	ret = sha1_vector(2, _addr, _len, mac);
89	forced_memzero(k_pad, sizeof(k_pad));
90	forced_memzero(tk, sizeof(tk));
91	return ret;
92}
93
94
95/**
96 * hmac_sha1 - HMAC-SHA1 over data buffer (RFC 2104)
97 * @key: Key for HMAC operations
98 * @key_len: Length of the key in bytes
99 * @data: Pointers to the data area
100 * @data_len: Length of the data area
101 * @mac: Buffer for the hash (20 bytes)
102 * Returns: 0 on success, -1 of failure
103 */
104int hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
105	       u8 *mac)
106{
107	return hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
108}
109