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 "utils/includes.h"
10
11 #ifdef EAP_PEAP
12
13 #include "utils/common.h"
14 #include "crypto/sha1.h"
15 #include "eap_peer/eap_peap_common.h"
16
17 int
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)18 peap_prfplus(int version, const u8 *key, size_t key_len,
19 const char *label, const u8 *seed, size_t seed_len,
20 u8 *buf, size_t buf_len)
21 {
22 unsigned char counter = 0;
23 size_t pos, plen;
24 u8 hash[SHA1_MAC_LEN];
25 size_t label_len = os_strlen(label);
26 u8 extra[2];
27 const unsigned char *addr[5];
28 size_t len[5];
29
30 addr[0] = hash;
31 len[0] = 0;
32 addr[1] = (unsigned char *) label;
33 len[1] = label_len;
34 addr[2] = seed;
35 len[2] = seed_len;
36
37 if (version == 0) {
38 /*
39 * PRF+(K, S, LEN) = T1 | T2 | ... | Tn
40 * T1 = HMAC-SHA1(K, S | 0x01 | 0x00 | 0x00)
41 * T2 = HMAC-SHA1(K, T1 | S | 0x02 | 0x00 | 0x00)
42 * ...
43 * Tn = HMAC-SHA1(K, Tn-1 | S | n | 0x00 | 0x00)
44 */
45
46 extra[0] = 0;
47 extra[1] = 0;
48
49 addr[3] = &counter;
50 len[3] = 1;
51 addr[4] = extra;
52 len[4] = 2;
53 } else {
54 /*
55 * PRF (K,S,LEN) = T1 | T2 | T3 | T4 | ... where:
56 * T1 = HMAC-SHA1(K, S | LEN | 0x01)
57 * T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02)
58 * T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03)
59 * T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04)
60 * ...
61 */
62
63 extra[0] = buf_len & 0xff;
64
65 addr[3] = extra;
66 len[3] = 1;
67 addr[4] = &counter;
68 len[4] = 1;
69 }
70
71 pos = 0;
72 while (pos < buf_len) {
73 counter++;
74 plen = buf_len - pos;
75 if (hmac_sha1_vector(key, key_len, 5, addr, len, hash) < 0)
76 return -1;
77 if (plen >= SHA1_MAC_LEN) {
78 os_memcpy(&buf[pos], hash, SHA1_MAC_LEN);
79 pos += SHA1_MAC_LEN;
80 } else {
81 os_memcpy(&buf[pos], hash, plen);
82 break;
83 }
84 len[0] = SHA1_MAC_LEN;
85 }
86
87 return 0;
88 }
89
90 #endif /* EAP_PEAP */
91
