1 /*
2 * EAP-PEAP common routines
3 * Copyright (c) 2008-2011, 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 "crypto/sha1.h"
13 #include "eap_peap_common.h"
14
peap_prfplus(int version,const u8 * key,size_t key_len,const char * label,const u8 * seed,size_t seed_len,u8 * buf,size_t buf_len)15 int peap_prfplus(int version, const u8 *key, size_t key_len,
16 const char *label, const u8 *seed, size_t seed_len,
17 u8 *buf, size_t buf_len)
18 {
19 unsigned char counter = 0;
20 size_t pos, plen;
21 u8 hash[SHA1_MAC_LEN];
22 size_t label_len = os_strlen(label);
23 u8 extra[2];
24 const unsigned char *addr[5];
25 size_t len[5];
26
27 addr[0] = hash;
28 len[0] = 0;
29 addr[1] = (unsigned char *) label;
30 len[1] = label_len;
31 addr[2] = seed;
32 len[2] = seed_len;
33
34 if (version == 0) {
35 /*
36 * PRF+(K, S, LEN) = T1 | T2 | ... | Tn
37 * T1 = HMAC-SHA1(K, S | 0x01 | 0x00 | 0x00)
38 * T2 = HMAC-SHA1(K, T1 | S | 0x02 | 0x00 | 0x00)
39 * ...
40 * Tn = HMAC-SHA1(K, Tn-1 | S | n | 0x00 | 0x00)
41 */
42
43 extra[0] = 0;
44 extra[1] = 0;
45
46 addr[3] = &counter;
47 len[3] = 1;
48 addr[4] = extra;
49 len[4] = 2;
50 } else {
51 /*
52 * PRF (K,S,LEN) = T1 | T2 | T3 | T4 | ... where:
53 * T1 = HMAC-SHA1(K, S | LEN | 0x01)
54 * T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02)
55 * T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03)
56 * T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04)
57 * ...
58 */
59
60 extra[0] = buf_len & 0xff;
61
62 addr[3] = extra;
63 len[3] = 1;
64 addr[4] = &counter;
65 len[4] = 1;
66 }
67
68 pos = 0;
69 while (pos < buf_len) {
70 counter++;
71 plen = buf_len - pos;
72 if (hmac_sha1_vector(key, key_len, 5, addr, len, hash) < 0)
73 return -1;
74 if (plen >= SHA1_MAC_LEN) {
75 os_memcpy(&buf[pos], hash, SHA1_MAC_LEN);
76 pos += SHA1_MAC_LEN;
77 } else {
78 os_memcpy(&buf[pos], hash, plen);
79 break;
80 }
81 len[0] = SHA1_MAC_LEN;
82 }
83
84 return 0;
85 }
86