294 lines
6.6 KiB
C
294 lines
6.6 KiB
C
/*
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* Copyright (C) 2009-2011 Martin Willi
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include "simaka_crypto.h"
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#include "simaka_manager.h"
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#include <utils/debug.h>
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/** length of the k_encr key */
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#define KENCR_LEN 16
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/** length of the k_auth key */
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#define KAUTH_LEN 16
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/** length of the MSK */
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#define MSK_LEN 64
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/** length of the EMSK */
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#define EMSK_LEN 64
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typedef struct private_simaka_crypto_t private_simaka_crypto_t;
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/**
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* Private data of an simaka_crypto_t object.
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*/
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struct private_simaka_crypto_t {
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/**
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* Public simaka_crypto_t interface.
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*/
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simaka_crypto_t public;
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/**
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* EAP type this crypto is used, SIM or AKA
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*/
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eap_type_t type;
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/**
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* signer to create/verify AT_MAC
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*/
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signer_t *signer;
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/**
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* crypter to encrypt/decrypt AT_ENCR_DATA
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*/
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crypter_t *crypter;
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/**
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* hasher used in key derivation
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*/
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hasher_t *hasher;
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/**
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* PRF function used in key derivation
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*/
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prf_t *prf;
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/**
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* Random number generator to generate nonces
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*/
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rng_t *rng;
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/**
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* Have k_encr/k_auth been derived?
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*/
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bool derived;
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};
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METHOD(simaka_crypto_t, get_signer, signer_t*,
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private_simaka_crypto_t *this)
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{
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return this->derived ? this->signer : NULL;
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}
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METHOD(simaka_crypto_t, get_crypter, crypter_t*,
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private_simaka_crypto_t *this)
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{
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return this->derived ? this->crypter : NULL;
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}
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METHOD(simaka_crypto_t, get_rng, rng_t*,
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private_simaka_crypto_t *this)
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{
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return this->rng;
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}
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/**
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* Call SIM/AKA key hook
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*/
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static void call_hook(private_simaka_crypto_t *this, chunk_t encr, chunk_t auth)
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{
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simaka_manager_t *mgr;
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switch (this->type)
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{
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case EAP_SIM:
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mgr = lib->get(lib, "sim-manager");
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break;
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case EAP_AKA:
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mgr = lib->get(lib, "aka-manager");
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break;
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default:
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return;
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}
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mgr->key_hook(mgr, encr, auth);
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}
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METHOD(simaka_crypto_t, derive_keys_full, bool,
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private_simaka_crypto_t *this, identification_t *id,
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chunk_t data, chunk_t *mk, chunk_t *msk)
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{
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chunk_t str, k_encr, k_auth;
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int i;
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/* For SIM: MK = SHA1(Identity|n*Kc|NONCE_MT|Version List|Selected Version)
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* For AKA: MK = SHA1(Identity|IK|CK) */
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if (!this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL) ||
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!this->hasher->allocate_hash(this->hasher, data, mk))
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{
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return FALSE;
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}
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DBG3(DBG_LIB, "MK %B", mk);
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/* K_encr | K_auth | MSK | EMSK = prf() | prf() | prf() | prf() */
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if (!this->prf->set_key(this->prf, *mk))
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{
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chunk_clear(mk);
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return FALSE;
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}
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str = chunk_alloca(this->prf->get_block_size(this->prf) * 3);
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for (i = 0; i < 3; i++)
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{
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if (!this->prf->get_bytes(this->prf, chunk_empty,
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str.ptr + str.len / 3 * i))
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{
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chunk_clear(mk);
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return FALSE;
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}
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}
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k_encr = chunk_create(str.ptr, KENCR_LEN);
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k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
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if (!this->signer->set_key(this->signer, k_auth) ||
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!this->crypter->set_key(this->crypter, k_encr))
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{
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chunk_clear(mk);
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return FALSE;
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}
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*msk = chunk_clone(chunk_create(str.ptr + KENCR_LEN + KAUTH_LEN, MSK_LEN));
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DBG3(DBG_LIB, "K_encr %B\nK_auth %B\nMSK %B", &k_encr, &k_auth, msk);
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call_hook(this, k_encr, k_auth);
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this->derived = TRUE;
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return TRUE;
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}
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METHOD(simaka_crypto_t, derive_keys_reauth, bool,
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private_simaka_crypto_t *this, chunk_t mk)
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{
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chunk_t str, k_encr, k_auth;
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int i;
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/* K_encr | K_auth = prf() | prf() */
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if (!this->prf->set_key(this->prf, mk))
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{
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return FALSE;
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}
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str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
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for (i = 0; i < 2; i++)
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{
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if (!this->prf->get_bytes(this->prf, chunk_empty,
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str.ptr + str.len / 2 * i))
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{
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return FALSE;
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}
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}
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k_encr = chunk_create(str.ptr, KENCR_LEN);
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k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
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DBG3(DBG_LIB, "K_encr %B\nK_auth %B", &k_encr, &k_auth);
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if (!this->signer->set_key(this->signer, k_auth) ||
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!this->crypter->set_key(this->crypter, k_encr))
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{
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return FALSE;
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}
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call_hook(this, k_encr, k_auth);
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this->derived = TRUE;
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return TRUE;
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}
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METHOD(simaka_crypto_t, derive_keys_reauth_msk, bool,
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private_simaka_crypto_t *this, identification_t *id, chunk_t counter,
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chunk_t nonce_s, chunk_t mk, chunk_t *msk)
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{
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char xkey[HASH_SIZE_SHA1];
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chunk_t str;
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int i;
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if (!this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL) ||
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!this->hasher->get_hash(this->hasher, counter, NULL) ||
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!this->hasher->get_hash(this->hasher, nonce_s, NULL) ||
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!this->hasher->get_hash(this->hasher, mk, xkey))
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{
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return FALSE;
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}
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/* MSK | EMSK = prf() | prf() | prf() | prf() */
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if (!this->prf->set_key(this->prf, chunk_create(xkey, sizeof(xkey))))
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{
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return FALSE;
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}
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str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
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for (i = 0; i < 2; i++)
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{
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if (!this->prf->get_bytes(this->prf, chunk_empty,
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str.ptr + str.len / 2 * i))
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{
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return FALSE;
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}
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}
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*msk = chunk_clone(chunk_create(str.ptr, MSK_LEN));
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DBG3(DBG_LIB, "MSK %B", msk);
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return TRUE;
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}
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METHOD(simaka_crypto_t, clear_keys, void,
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private_simaka_crypto_t *this)
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{
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this->derived = FALSE;
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}
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METHOD(simaka_crypto_t, destroy, void,
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private_simaka_crypto_t *this)
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{
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DESTROY_IF(this->rng);
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DESTROY_IF(this->hasher);
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DESTROY_IF(this->prf);
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DESTROY_IF(this->signer);
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DESTROY_IF(this->crypter);
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free(this);
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}
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/**
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* See header
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*/
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simaka_crypto_t *simaka_crypto_create(eap_type_t type)
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{
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private_simaka_crypto_t *this;
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INIT(this,
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.public = {
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.get_signer = _get_signer,
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.get_crypter = _get_crypter,
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.get_rng = _get_rng,
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.derive_keys_full = _derive_keys_full,
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.derive_keys_reauth = _derive_keys_reauth,
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.derive_keys_reauth_msk = _derive_keys_reauth_msk,
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.clear_keys = _clear_keys,
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.destroy = _destroy,
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},
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.type = type,
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.rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
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.hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1),
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.prf = lib->crypto->create_prf(lib->crypto, PRF_FIPS_SHA1_160),
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.signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_SHA1_128),
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.crypter = lib->crypto->create_crypter(lib->crypto, ENCR_AES_CBC, 16),
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);
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if (!this->rng || !this->hasher || !this->prf ||
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!this->signer || !this->crypter)
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{
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DBG1(DBG_LIB, "unable to use %N, missing algorithms",
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eap_type_names, type);
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destroy(this);
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return NULL;
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}
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return &this->public;
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}
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