hostap/src/eap_common/eap_peap_common.c

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/*
* EAP-PEAP common routines
* Copyright (c) 2008-2011, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/sha1.h"
#include "eap_peap_common.h"
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)
{
unsigned char counter = 0;
size_t pos, plen;
u8 hash[SHA1_MAC_LEN];
size_t label_len = os_strlen(label);
u8 extra[2];
const unsigned char *addr[5];
size_t len[5];
addr[0] = hash;
len[0] = 0;
addr[1] = (unsigned char *) label;
len[1] = label_len;
addr[2] = seed;
len[2] = seed_len;
if (version == 0) {
/*
* PRF+(K, S, LEN) = T1 | T2 | ... | Tn
* T1 = HMAC-SHA1(K, S | 0x01 | 0x00 | 0x00)
* T2 = HMAC-SHA1(K, T1 | S | 0x02 | 0x00 | 0x00)
* ...
* Tn = HMAC-SHA1(K, Tn-1 | S | n | 0x00 | 0x00)
*/
extra[0] = 0;
extra[1] = 0;
addr[3] = &counter;
len[3] = 1;
addr[4] = extra;
len[4] = 2;
} else {
/*
* PRF (K,S,LEN) = T1 | T2 | T3 | T4 | ... where:
* T1 = HMAC-SHA1(K, S | LEN | 0x01)
* T2 = HMAC-SHA1 (K, T1 | S | LEN | 0x02)
* T3 = HMAC-SHA1 (K, T2 | S | LEN | 0x03)
* T4 = HMAC-SHA1 (K, T3 | S | LEN | 0x04)
* ...
*/
extra[0] = buf_len & 0xff;
addr[3] = extra;
len[3] = 1;
addr[4] = &counter;
len[4] = 1;
}
pos = 0;
while (pos < buf_len) {
counter++;
plen = buf_len - pos;
if (hmac_sha1_vector(key, key_len, 5, addr, len, hash) < 0)
return -1;
if (plen >= SHA1_MAC_LEN) {
os_memcpy(&buf[pos], hash, SHA1_MAC_LEN);
pos += SHA1_MAC_LEN;
} else {
os_memcpy(&buf[pos], hash, plen);
break;
}
len[0] = SHA1_MAC_LEN;
}
return 0;
}