wpa_supplicant_node: eap_peap_common.c Source File

00001 /*
00002  * EAP-PEAP common routines
00003  * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License version 2 as
00007  * published by the Free Software Foundation.
00008  *
00009  * Alternatively, this software may be distributed under the terms of BSD
00010  * license.
00011  *
00012  * See README and COPYING for more details.
00013  */
00014 
00015 #include "includes.h"
00016 
00017 #include "common.h"
00018 #include "crypto/sha1.h"
00019 #include "eap_peap_common.h"
00020 
00021 void peap_prfplus(int version, const u8 *key, size_t key_len,
00022                   const char *label, const u8 *seed, size_t seed_len,
00023                   u8 *buf, size_t buf_len)
00024 {
00025         unsigned char counter = 0;
00026         size_t pos, plen;
00027         u8 hash[SHA1_MAC_LEN];
00028         size_t label_len = os_strlen(label);
00029         u8 extra[2];
00030         const unsigned char *addr[5];
00031         size_t len[5];
00032 
00033         addr[0] = hash;
00034         len[0] = 0;
00035         addr[1] = (unsigned char *) label;
00036         len[1] = label_len;
00037         addr[2] = seed;
00038         len[2] = seed_len;
00039 
00040         if (version == 0) {
00041                 /*
00042                  * PRF+(K, S, LEN) = T1 | T2 | ... | Tn
00043                  * T1 = HMAC-SHA1(K, S | 0x01 | 0x00 | 0x00)
00044                  * T2 = HMAC-SHA1(K, T1 | S | 0x02 | 0x00 | 0x00)
00045                  * ...
00046                  * Tn = HMAC-SHA1(K, Tn-1 | S | n | 0x00 | 0x00)
00047                  */
00048 
00049                 extra[0] = 0;
00050                 extra[1] = 0;
00051 
00052                 addr[3] = &counter;
00053                 len[3] = 1;
00054                 addr[4] = extra;
00055                 len[4] = 2;
00056         } else {
00057                 /*
00058                  * PRF (K,S,LEN) = T1 | T2 | T3 | T4 | ... where:
00059                  * T1 = HMAC-SHA1(K, S | LEN | 0x01)
00060                  * T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02)
00061                  * T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03)
00062                  * T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04)
00063                  *   ...
00064                  */
00065 
00066                 extra[0] = buf_len & 0xff;
00067 
00068                 addr[3] = extra;
00069                 len[3] = 1;
00070                 addr[4] = &counter;
00071                 len[4] = 1;
00072         }
00073 
00074         pos = 0;
00075         while (pos < buf_len) {
00076                 counter++;
00077                 plen = buf_len - pos;
00078                 hmac_sha1_vector(key, key_len, 5, addr, len, hash);
00079                 if (plen >= SHA1_MAC_LEN) {
00080                         os_memcpy(&buf[pos], hash, SHA1_MAC_LEN);
00081                         pos += SHA1_MAC_LEN;
00082                 } else {
00083                         os_memcpy(&buf[pos], hash, plen);
00084                         break;
00085                 }
00086                 len[0] = SHA1_MAC_LEN;
00087         }
00088 }