/* * QEMU Crypto block device encryption QCow/QCow2 AES-CBC format * * 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/>. * */ /* * Note that the block encryption implemented in this file is broken * by design. This exists only to allow data to be liberated from * existing qcow[2] images and should not be used in any new areas. */ #include "qemu/osdep.h" #include "qapi/error.h" #include "block-qcow.h" #include "crypto/secret.h" #define QCRYPTO_BLOCK_QCOW_SECTOR_SIZE 512 static bool qcrypto_block_qcow_has_format(const uint8_t *buf G_GNUC_UNUSED, size_t buf_size G_GNUC_UNUSED) { return false; } static int qcrypto_block_qcow_init(QCryptoBlock *block, const char *keysecret, size_t n_threads, Error **errp) { char *password; int ret; uint8_t keybuf[16]; int len; memset(keybuf, 0, 16); password = qcrypto_secret_lookup_as_utf8(keysecret, errp); if (!password) { return -1; } len = strlen(password); memcpy(keybuf, password, MIN(len, sizeof(keybuf))); g_free(password); block->niv = qcrypto_cipher_get_iv_len(QCRYPTO_CIPHER_ALG_AES_128, QCRYPTO_CIPHER_MODE_CBC); block->ivgen = qcrypto_ivgen_new(QCRYPTO_IVGEN_ALG_PLAIN64, 0, 0, NULL, 0, errp); if (!block->ivgen) { ret = -ENOTSUP; goto fail; } ret = qcrypto_block_init_cipher(block, QCRYPTO_CIPHER_ALG_AES_128, QCRYPTO_CIPHER_MODE_CBC, keybuf, G_N_ELEMENTS(keybuf), n_threads, errp); if (ret < 0) { ret = -ENOTSUP; goto fail; } block->sector_size = QCRYPTO_BLOCK_QCOW_SECTOR_SIZE; block->payload_offset = 0; return 0; fail: qcrypto_block_free_cipher(block); qcrypto_ivgen_free(block->ivgen); return ret; } static int qcrypto_block_qcow_open(QCryptoBlock *block, QCryptoBlockOpenOptions *options, const char *optprefix, QCryptoBlockReadFunc readfunc G_GNUC_UNUSED, void *opaque G_GNUC_UNUSED, unsigned int flags, size_t n_threads, Error **errp) { if (flags & QCRYPTO_BLOCK_OPEN_NO_IO) { block->sector_size = QCRYPTO_BLOCK_QCOW_SECTOR_SIZE; block->payload_offset = 0; return 0; } else { if (!options->u.qcow.key_secret) { error_setg(errp, "Parameter '%skey-secret' is required for cipher", optprefix ? optprefix : ""); return -1; } return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, n_threads, errp); } } static int qcrypto_block_qcow_create(QCryptoBlock *block, QCryptoBlockCreateOptions *options, const char *optprefix, QCryptoBlockInitFunc initfunc G_GNUC_UNUSED, QCryptoBlockWriteFunc writefunc G_GNUC_UNUSED, void *opaque G_GNUC_UNUSED, Error **errp) { if (!options->u.qcow.key_secret) { error_setg(errp, "Parameter '%skey-secret' is required for cipher", optprefix ? optprefix : ""); return -1; } /* QCow2 has no special header, since everything is hardwired */ return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, 1, errp); } static void qcrypto_block_qcow_cleanup(QCryptoBlock *block) { } static int qcrypto_block_qcow_decrypt(QCryptoBlock *block, uint64_t offset, uint8_t *buf, size_t len, Error **errp) { assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); return qcrypto_block_decrypt_helper(block, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, offset, buf, len, errp); } static int qcrypto_block_qcow_encrypt(QCryptoBlock *block, uint64_t offset, uint8_t *buf, size_t len, Error **errp) { assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); return qcrypto_block_encrypt_helper(block, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, offset, buf, len, errp); } const QCryptoBlockDriver qcrypto_block_driver_qcow = { .open = qcrypto_block_qcow_open, .create = qcrypto_block_qcow_create, .cleanup = qcrypto_block_qcow_cleanup, .decrypt = qcrypto_block_qcow_decrypt, .encrypt = qcrypto_block_qcow_encrypt, .has_format = qcrypto_block_qcow_has_format, };