diff options
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/Makefile.objs | 1 | ||||
| -rw-r--r-- | crypto/afsplit.c | 158 |
2 files changed, 159 insertions, 0 deletions
diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs index f28b00e549..454f9dba39 100644 --- a/crypto/Makefile.objs +++ b/crypto/Makefile.objs @@ -17,6 +17,7 @@ crypto-obj-y += ivgen.o crypto-obj-y += ivgen-essiv.o crypto-obj-y += ivgen-plain.o crypto-obj-y += ivgen-plain64.o +crypto-obj-y += afsplit.o # Let the userspace emulators avoid linking gnutls/etc crypto-aes-obj-y = aes.o diff --git a/crypto/afsplit.c b/crypto/afsplit.c new file mode 100644 index 0000000000..8074913cdd --- /dev/null +++ b/crypto/afsplit.c @@ -0,0 +1,158 @@ +/* + * 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 library 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 library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + * + */ + +#include "qemu/osdep.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; +} |