119 lines
3.9 KiB
C
119 lines
3.9 KiB
C
/**
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* @file OTPCalculator.c
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <limits.h>
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#include <misc/balloc.h>
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#include <security/OTPCalculator.h>
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int OTPCalculator_Init (OTPCalculator *calc, int num_otps, int cipher)
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{
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ASSERT(num_otps >= 0)
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ASSERT(BEncryption_cipher_valid(cipher))
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// init arguments
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calc->num_otps = num_otps;
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calc->cipher = cipher;
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// remember block size
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calc->block_size = BEncryption_cipher_block_size(calc->cipher);
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// calculate number of blocks
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if (calc->num_otps > SIZE_MAX / sizeof(otp_t)) {
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goto fail0;
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}
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calc->num_blocks = bdivide_up(calc->num_otps * sizeof(otp_t), calc->block_size);
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// allocate buffer
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if (!(calc->data = (otp_t *)BAllocArray(calc->num_blocks, calc->block_size))) {
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goto fail0;
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}
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// init debug object
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DebugObject_Init(&calc->d_obj);
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return 1;
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fail0:
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return 0;
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}
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void OTPCalculator_Free (OTPCalculator *calc)
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{
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// free debug object
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DebugObject_Free(&calc->d_obj);
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// free buffer
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BFree(calc->data);
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}
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otp_t * OTPCalculator_Generate (OTPCalculator *calc, uint8_t *key, uint8_t *iv, int shuffle)
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{
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ASSERT(shuffle == 0 || shuffle == 1)
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// copy IV so it can be updated
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uint8_t iv_work[BENCRYPTION_MAX_BLOCK_SIZE];
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memcpy(iv_work, iv, calc->block_size);
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// create zero block
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uint8_t zero[BENCRYPTION_MAX_BLOCK_SIZE];
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memset(zero, 0, calc->block_size);
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// init encryptor
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BEncryption encryptor;
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BEncryption_Init(&encryptor, BENCRYPTION_MODE_ENCRYPT, calc->cipher, key);
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// encrypt zero blocks
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for (size_t i = 0; i < calc->num_blocks; i++) {
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BEncryption_Encrypt(&encryptor, zero, (uint8_t *)calc->data + i * calc->block_size, calc->block_size, iv_work);
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}
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// free encryptor
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BEncryption_Free(&encryptor);
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// shuffle if requested
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if (shuffle) {
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int i = 0;
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while (i < calc->num_otps) {
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uint16_t ints[256];
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BRandom_randomize((uint8_t *)ints, sizeof(ints));
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for (int j = 0; j < 256 && i < calc->num_otps; j++) {
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int newIndex = i + (ints[j] % (calc->num_otps - i));
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otp_t temp = calc->data[i];
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calc->data[i] = calc->data[newIndex];
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calc->data[newIndex] = temp;
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i++;
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}
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}
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}
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return calc->data;
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}
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