| /* |
| * QEMU Crypto anti forensic information splitter |
| * |
| * Copyright (c) 2015-2016 Red Hat, Inc. |
| * |
| * Derived from cryptsetup package lib/luks1/af.c |
| * |
| * Copyright (C) 2004, Clemens Fruhwirth <clemens@endorphin.org> |
| * Copyright (C) 2009-2012, Red Hat, Inc. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version 2 |
| * of the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu/bswap.h" |
| #include "crypto/afsplit.h" |
| #include "crypto/random.h" |
| |
| |
| static void qcrypto_afsplit_xor(size_t blocklen, |
| const uint8_t *in1, |
| const uint8_t *in2, |
| uint8_t *out) |
| { |
| size_t i; |
| for (i = 0; i < blocklen; i++) { |
| out[i] = in1[i] ^ in2[i]; |
| } |
| } |
| |
| |
| static int qcrypto_afsplit_hash(QCryptoHashAlgorithm hash, |
| size_t blocklen, |
| uint8_t *block, |
| Error **errp) |
| { |
| size_t digestlen = qcrypto_hash_digest_len(hash); |
| |
| size_t hashcount = blocklen / digestlen; |
| size_t finallen = blocklen % digestlen; |
| uint32_t i; |
| |
| if (finallen) { |
| hashcount++; |
| } else { |
| finallen = digestlen; |
| } |
| |
| for (i = 0; i < hashcount; i++) { |
| uint8_t *out = NULL; |
| size_t outlen = 0; |
| uint32_t iv = cpu_to_be32(i); |
| struct iovec in[] = { |
| { .iov_base = &iv, |
| .iov_len = sizeof(iv) }, |
| { .iov_base = block + (i * digestlen), |
| .iov_len = (i == (hashcount - 1)) ? finallen : digestlen }, |
| }; |
| |
| if (qcrypto_hash_bytesv(hash, |
| in, |
| G_N_ELEMENTS(in), |
| &out, &outlen, |
| errp) < 0) { |
| return -1; |
| } |
| |
| assert(outlen == digestlen); |
| memcpy(block + (i * digestlen), out, |
| (i == (hashcount - 1)) ? finallen : digestlen); |
| g_free(out); |
| } |
| |
| return 0; |
| } |
| |
| |
| int qcrypto_afsplit_encode(QCryptoHashAlgorithm hash, |
| size_t blocklen, |
| uint32_t stripes, |
| const uint8_t *in, |
| uint8_t *out, |
| Error **errp) |
| { |
| uint8_t *block = g_new0(uint8_t, blocklen); |
| size_t i; |
| int ret = -1; |
| |
| for (i = 0; i < (stripes - 1); i++) { |
| if (qcrypto_random_bytes(out + (i * blocklen), blocklen, errp) < 0) { |
| goto cleanup; |
| } |
| |
| qcrypto_afsplit_xor(blocklen, |
| out + (i * blocklen), |
| block, |
| block); |
| if (qcrypto_afsplit_hash(hash, blocklen, block, |
| errp) < 0) { |
| goto cleanup; |
| } |
| } |
| qcrypto_afsplit_xor(blocklen, |
| in, |
| block, |
| out + (i * blocklen)); |
| ret = 0; |
| |
| cleanup: |
| g_free(block); |
| return ret; |
| } |
| |
| |
| int qcrypto_afsplit_decode(QCryptoHashAlgorithm hash, |
| size_t blocklen, |
| uint32_t stripes, |
| const uint8_t *in, |
| uint8_t *out, |
| Error **errp) |
| { |
| uint8_t *block = g_new0(uint8_t, blocklen); |
| size_t i; |
| int ret = -1; |
| |
| for (i = 0; i < (stripes - 1); i++) { |
| qcrypto_afsplit_xor(blocklen, |
| in + (i * blocklen), |
| block, |
| block); |
| if (qcrypto_afsplit_hash(hash, blocklen, block, |
| errp) < 0) { |
| goto cleanup; |
| } |
| } |
| |
| qcrypto_afsplit_xor(blocklen, |
| in + (i * blocklen), |
| block, |
| out); |
| |
| ret = 0; |
| |
| cleanup: |
| g_free(block); |
| return ret; |
| } |