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00001 /* 00002 * SHA1 T-PRF for EAP-FAST 00003 * Copyright (c) 2003-2005, 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 "sha1.h" 00019 #include "crypto.h" 00020 00035 int sha1_t_prf(const u8 *key, size_t key_len, const char *label, 00036 const u8 *seed, size_t seed_len, u8 *buf, size_t buf_len) 00037 { 00038 unsigned char counter = 0; 00039 size_t pos, plen; 00040 u8 hash[SHA1_MAC_LEN]; 00041 size_t label_len = os_strlen(label); 00042 u8 output_len[2]; 00043 const unsigned char *addr[5]; 00044 size_t len[5]; 00045 00046 addr[0] = hash; 00047 len[0] = 0; 00048 addr[1] = (unsigned char *) label; 00049 len[1] = label_len + 1; 00050 addr[2] = seed; 00051 len[2] = seed_len; 00052 addr[3] = output_len; 00053 len[3] = 2; 00054 addr[4] = &counter; 00055 len[4] = 1; 00056 00057 output_len[0] = (buf_len >> 8) & 0xff; 00058 output_len[1] = buf_len & 0xff; 00059 pos = 0; 00060 while (pos < buf_len) { 00061 counter++; 00062 plen = buf_len - pos; 00063 if (hmac_sha1_vector(key, key_len, 5, addr, len, hash)) 00064 return -1; 00065 if (plen >= SHA1_MAC_LEN) { 00066 os_memcpy(&buf[pos], hash, SHA1_MAC_LEN); 00067 pos += SHA1_MAC_LEN; 00068 } else { 00069 os_memcpy(&buf[pos], hash, plen); 00070 break; 00071 } 00072 len[0] = SHA1_MAC_LEN; 00073 } 00074 00075 return 0; 00076 }