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 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