hostap/src/eap_common/eap_psk_common.c

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/*
* EAP server/peer: EAP-PSK shared routines
* Copyright (c) 2004-2006, 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/aes_wrap.h"
#include "eap_defs.h"
#include "eap_psk_common.h"
#define aes_block_size 16
int eap_psk_key_setup(const u8 *psk, u8 *ak, u8 *kdk)
{
os_memset(ak, 0, aes_block_size);
if (aes_128_encrypt_block(psk, ak, ak))
return -1;
os_memcpy(kdk, ak, aes_block_size);
ak[aes_block_size - 1] ^= 0x01;
kdk[aes_block_size - 1] ^= 0x02;
if (aes_128_encrypt_block(psk, ak, ak) ||
aes_128_encrypt_block(psk, kdk, kdk))
return -1;
return 0;
}
int eap_psk_derive_keys(const u8 *kdk, const u8 *rand_p, u8 *tek, u8 *msk,
u8 *emsk)
{
u8 hash[aes_block_size];
u8 counter = 1;
int i;
if (aes_128_encrypt_block(kdk, rand_p, hash))
return -1;
hash[aes_block_size - 1] ^= counter;
if (aes_128_encrypt_block(kdk, hash, tek))
return -1;
hash[aes_block_size - 1] ^= counter;
counter++;
for (i = 0; i < EAP_MSK_LEN / aes_block_size; i++) {
hash[aes_block_size - 1] ^= counter;
if (aes_128_encrypt_block(kdk, hash, &msk[i * aes_block_size]))
return -1;
hash[aes_block_size - 1] ^= counter;
counter++;
}
for (i = 0; i < EAP_EMSK_LEN / aes_block_size; i++) {
hash[aes_block_size - 1] ^= counter;
if (aes_128_encrypt_block(kdk, hash,
&emsk[i * aes_block_size]))
return -1;
hash[aes_block_size - 1] ^= counter;
counter++;
}
return 0;
}