/*
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* EAP server/peer: EAP-PSK shared routines
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* Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "crypto/aes_wrap.h"
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#include "eap_defs.h"
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#include "eap_psk_common.h"
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#define aes_block_size 16
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int eap_psk_key_setup(const u8 *psk, u8 *ak, u8 *kdk)
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{
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os_memset(ak, 0, aes_block_size);
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if (aes_128_encrypt_block(psk, ak, ak))
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return -1;
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os_memcpy(kdk, ak, aes_block_size);
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ak[aes_block_size - 1] ^= 0x01;
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kdk[aes_block_size - 1] ^= 0x02;
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if (aes_128_encrypt_block(psk, ak, ak) ||
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aes_128_encrypt_block(psk, kdk, kdk))
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return -1;
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return 0;
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}
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int eap_psk_derive_keys(const u8 *kdk, const u8 *rand_p, u8 *tek, u8 *msk,
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u8 *emsk)
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{
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u8 hash[aes_block_size];
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u8 counter = 1;
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int i;
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if (aes_128_encrypt_block(kdk, rand_p, hash))
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return -1;
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hash[aes_block_size - 1] ^= counter;
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if (aes_128_encrypt_block(kdk, hash, tek))
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return -1;
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hash[aes_block_size - 1] ^= counter;
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counter++;
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for (i = 0; i < EAP_MSK_LEN / aes_block_size; i++) {
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hash[aes_block_size - 1] ^= counter;
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if (aes_128_encrypt_block(kdk, hash, &msk[i * aes_block_size]))
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return -1;
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hash[aes_block_size - 1] ^= counter;
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counter++;
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}
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for (i = 0; i < EAP_EMSK_LEN / aes_block_size; i++) {
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hash[aes_block_size - 1] ^= counter;
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if (aes_128_encrypt_block(kdk, hash,
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&emsk[i * aes_block_size]))
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return -1;
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hash[aes_block_size - 1] ^= counter;
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counter++;
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}
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return 0;
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}
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