/* * QEMU Crypto block IV generator - essiv * * Copyright (c) 2015-2016 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 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 "qemu/bswap.h" #include "ivgen-essiv.h" typedef struct QCryptoIVGenESSIV QCryptoIVGenESSIV; struct QCryptoIVGenESSIV { QCryptoCipher *cipher; }; static int qcrypto_ivgen_essiv_init(QCryptoIVGen *ivgen, const uint8_t *key, size_t nkey, Error **errp) { uint8_t *salt; size_t nhash; size_t nsalt; QCryptoIVGenESSIV *essiv = g_new0(QCryptoIVGenESSIV, 1); /* Not necessarily the same as nkey */ nsalt = qcrypto_cipher_get_key_len(ivgen->cipher); nhash = qcrypto_hash_digest_len(ivgen->hash); /* Salt must be larger of hash size or key size */ salt = g_new0(uint8_t, MAX(nhash, nsalt)); if (qcrypto_hash_bytes(ivgen->hash, (const gchar *)key, nkey, &salt, &nhash, errp) < 0) { g_free(essiv); g_free(salt); return -1; } /* Now potentially truncate salt to match cipher key len */ essiv->cipher = qcrypto_cipher_new(ivgen->cipher, QCRYPTO_CIPHER_MODE_ECB, salt, MIN(nhash, nsalt), errp); if (!essiv->cipher) { g_free(essiv); g_free(salt); return -1; } g_free(salt); ivgen->private = essiv; return 0; } static int qcrypto_ivgen_essiv_calculate(QCryptoIVGen *ivgen, uint64_t sector, uint8_t *iv, size_t niv, Error **errp) { QCryptoIVGenESSIV *essiv = ivgen->private; size_t ndata = qcrypto_cipher_get_block_len(ivgen->cipher); uint8_t *data = g_new(uint8_t, ndata); sector = cpu_to_le64(sector); memcpy(data, (uint8_t *)§or, MIN(sizeof(sector), ndata)); if (sizeof(sector) < ndata) { memset(data + sizeof(sector), 0, ndata - sizeof(sector)); } if (qcrypto_cipher_encrypt(essiv->cipher, data, data, ndata, errp) < 0) { g_free(data); return -1; } if (ndata > niv) { ndata = niv; } memcpy(iv, data, ndata); if (ndata < niv) { memset(iv + ndata, 0, niv - ndata); } g_free(data); return 0; } static void qcrypto_ivgen_essiv_cleanup(QCryptoIVGen *ivgen) { QCryptoIVGenESSIV *essiv = ivgen->private; qcrypto_cipher_free(essiv->cipher); g_free(essiv); } struct QCryptoIVGenDriver qcrypto_ivgen_essiv = { .init = qcrypto_ivgen_essiv_init, .calculate = qcrypto_ivgen_essiv_calculate, .cleanup = qcrypto_ivgen_essiv_cleanup, };