1 /* 2 * EAP-PEAP common routines 3 * Copyright (c) 2008, Jouni Malinen <j (at) w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15 #include "includes.h" 16 17 #include "common.h" 18 #include "crypto/sha1.h" 19 #include "eap_peap_common.h" 20 21 void peap_prfplus(int version, const u8 *key, size_t key_len, 22 const char *label, const u8 *seed, size_t seed_len, 23 u8 *buf, size_t buf_len) 24 { 25 unsigned char counter = 0; 26 size_t pos, plen; 27 u8 hash[SHA1_MAC_LEN]; 28 size_t label_len = os_strlen(label); 29 u8 extra[2]; 30 const unsigned char *addr[5]; 31 size_t len[5]; 32 33 addr[0] = hash; 34 len[0] = 0; 35 addr[1] = (unsigned char *) label; 36 len[1] = label_len; 37 addr[2] = seed; 38 len[2] = seed_len; 39 40 if (version == 0) { 41 /* 42 * PRF+(K, S, LEN) = T1 | T2 | ... | Tn 43 * T1 = HMAC-SHA1(K, S | 0x01 | 0x00 | 0x00) 44 * T2 = HMAC-SHA1(K, T1 | S | 0x02 | 0x00 | 0x00) 45 * ... 46 * Tn = HMAC-SHA1(K, Tn-1 | S | n | 0x00 | 0x00) 47 */ 48 49 extra[0] = 0; 50 extra[1] = 0; 51 52 addr[3] = &counter; 53 len[3] = 1; 54 addr[4] = extra; 55 len[4] = 2; 56 } else { 57 /* 58 * PRF (K,S,LEN) = T1 | T2 | T3 | T4 | ... where: 59 * T1 = HMAC-SHA1(K, S | LEN | 0x01) 60 * T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02) 61 * T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03) 62 * T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04) 63 * ... 64 */ 65 66 extra[0] = buf_len & 0xff; 67 68 addr[3] = extra; 69 len[3] = 1; 70 addr[4] = &counter; 71 len[4] = 1; 72 } 73 74 pos = 0; 75 while (pos < buf_len) { 76 counter++; 77 plen = buf_len - pos; 78 hmac_sha1_vector(key, key_len, 5, addr, len, hash); 79 if (plen >= SHA1_MAC_LEN) { 80 os_memcpy(&buf[pos], hash, SHA1_MAC_LEN); 81 pos += SHA1_MAC_LEN; 82 } else { 83 os_memcpy(&buf[pos], hash, plen); 84 break; 85 } 86 len[0] = SHA1_MAC_LEN; 87 } 88 } 89
