8b3f5a8ad7
Instead of having our own copy of the AES code, use a good library to do that. Crypto++ is well-maintained, supports a lot of ciphers, works on many OSes, and is optimized for many architectures. Change-Id: I7d7d24b47993206d7338c5f9bac8bbdd3915a667
126 lines
4.2 KiB
C++
126 lines
4.2 KiB
C++
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2016 Amaury Pouly
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "crypto.h"
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#include "misc.h"
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#include <cryptopp/modes.h>
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#include <cryptopp/aes.h>
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using namespace CryptoPP;
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namespace
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{
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enum crypto_method_t g_cur_method = CRYPTO_NONE;
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byte g_key[16];
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CBC_Mode<AES>::Encryption g_aes_enc;
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CBC_Mode<AES>::Decryption g_aes_dec;
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bool g_aes_enc_key_dirty; /* true of g_aes_enc key needs to be updated */
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bool g_aes_dec_key_dirty; /* same for g_aes_dec */
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int cbc_mac2(
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const byte *in_data, /* Input data */
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byte *out_data, /* Output data (or NULL) */
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int nr_blocks, /* Number of blocks to encrypt/decrypt (one block=16 bytes) */
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byte key[16], /* Key */
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byte iv[16], /* Initialisation Vector */
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byte (*out_cbc_mac)[16], /* CBC-MAC of the result (or NULL) */
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bool encrypt /* 1 to encrypt, 0 to decrypt */
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)
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{
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/* encrypt */
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if(encrypt)
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{
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/* update keys if neeeded */
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if(g_aes_enc_key_dirty)
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{
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/* we need to provide an IV with the key, although we change it
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* everytime we run the cipher anyway */
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g_aes_enc.SetKeyWithIV(g_key, 16, iv, 16);
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g_aes_enc_key_dirty = false;
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}
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g_aes_enc.Resynchronize(iv, 16);
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byte tmp[16];
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/* we need some output buffer, either a temporary one if we are CBC-MACing
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* only, or use output buffer if available */
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byte *out_ptr = (out_data == NULL) ? tmp : out_data;
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while(nr_blocks-- > 0)
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{
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g_aes_enc.ProcessData(out_ptr, in_data, 16);
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/* if this is the last block, copy CBC-MAC */
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if(nr_blocks == 0 && out_cbc_mac)
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memcpy(out_cbc_mac, out_ptr, 16);
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/* if we are writing data to the output buffer, advance output pointer */
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if(out_data != NULL)
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out_ptr += 16;
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in_data += 16;
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}
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return CRYPTO_ERROR_SUCCESS;
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}
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/* decrypt */
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else
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{
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/* update keys if neeeded */
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if(g_aes_dec_key_dirty)
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{
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/* we need to provide an IV with the key, although we change it
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* everytime we run the cipher anyway */
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g_aes_dec.SetKeyWithIV(g_key, 16, iv, 16);
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g_aes_dec_key_dirty = false;
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}
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/* we cannot produce a CBC-MAC in decrypt mode, output buffer exists */
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if(out_cbc_mac || out_data == NULL)
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return CRYPTO_ERROR_INVALID_OP;
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g_aes_dec.Resynchronize(iv, 16);
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g_aes_dec.ProcessData(out_data, in_data, nr_blocks * 16);
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return CRYPTO_ERROR_SUCCESS;
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}
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}
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}
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int crypto_setup(struct crypto_key_t *key)
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{
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g_cur_method = key->method;
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switch(g_cur_method)
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{
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case CRYPTO_KEY:
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memcpy(g_key, key->u.key, 16);
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g_aes_dec_key_dirty = true;
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g_aes_enc_key_dirty = true;
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return CRYPTO_ERROR_SUCCESS;
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default:
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return CRYPTO_ERROR_BADSETUP;
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}
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}
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int crypto_apply(
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byte *in_data, /* Input data */
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byte *out_data, /* Output data (or NULL) */
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int nr_blocks, /* Number of blocks (one block=16 bytes) */
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byte iv[16], /* Key */
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byte (*out_cbc_mac)[16], /* CBC-MAC of the result (or NULL) */
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bool encrypt)
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{
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if(g_cur_method == CRYPTO_KEY)
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return cbc_mac2(in_data, out_data, nr_blocks, g_key, iv, out_cbc_mac, encrypt);
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else
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return CRYPTO_ERROR_BADSETUP;
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}
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