/* * QEMU block full disk encryption * * 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 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 "block/block_int.h" #include "sysemu/block-backend.h" #include "crypto/block.h" #include "qapi/opts-visitor.h" #include "qapi-visit.h" #include "qapi/error.h" #define BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET "key-secret" #define BLOCK_CRYPTO_OPT_LUKS_CIPHER_ALG "cipher-alg" #define BLOCK_CRYPTO_OPT_LUKS_CIPHER_MODE "cipher-mode" #define BLOCK_CRYPTO_OPT_LUKS_IVGEN_ALG "ivgen-alg" #define BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG "ivgen-hash-alg" #define BLOCK_CRYPTO_OPT_LUKS_HASH_ALG "hash-alg" typedef struct BlockCrypto BlockCrypto; struct BlockCrypto { QCryptoBlock *block; }; static int block_crypto_probe_generic(QCryptoBlockFormat format, const uint8_t *buf, int buf_size, const char *filename) { if (qcrypto_block_has_format(format, buf, buf_size)) { return 100; } else { return 0; } } static ssize_t block_crypto_read_func(QCryptoBlock *block, size_t offset, uint8_t *buf, size_t buflen, Error **errp, void *opaque) { BlockDriverState *bs = opaque; ssize_t ret; ret = bdrv_pread(bs->file, offset, buf, buflen); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read encryption header"); return ret; } return ret; } struct BlockCryptoCreateData { const char *filename; QemuOpts *opts; BlockBackend *blk; uint64_t size; }; static ssize_t block_crypto_write_func(QCryptoBlock *block, size_t offset, const uint8_t *buf, size_t buflen, Error **errp, void *opaque) { struct BlockCryptoCreateData *data = opaque; ssize_t ret; ret = blk_pwrite(data->blk, offset, buf, buflen, 0); if (ret < 0) { error_setg_errno(errp, -ret, "Could not write encryption header"); return ret; } return ret; } static ssize_t block_crypto_init_func(QCryptoBlock *block, size_t headerlen, Error **errp, void *opaque) { struct BlockCryptoCreateData *data = opaque; int ret; /* User provided size should reflect amount of space made * available to the guest, so we must take account of that * which will be used by the crypto header */ data->size += headerlen; qemu_opt_set_number(data->opts, BLOCK_OPT_SIZE, data->size, &error_abort); ret = bdrv_create_file(data->filename, data->opts, errp); if (ret < 0) { return -1; } data->blk = blk_new_open(data->filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, errp); if (!data->blk) { return -1; } return 0; } static QemuOptsList block_crypto_runtime_opts_luks = { .name = "crypto", .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head), .desc = { { .name = BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, .type = QEMU_OPT_STRING, .help = "ID of the secret that provides the encryption key", }, { /* end of list */ } }, }; static QemuOptsList block_crypto_create_opts_luks = { .name = "crypto", .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), .desc = { { .name = BLOCK_OPT_SIZE, .type = QEMU_OPT_SIZE, .help = "Virtual disk size" }, { .name = BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, .type = QEMU_OPT_STRING, .help = "ID of the secret that provides the encryption key", }, { .name = BLOCK_CRYPTO_OPT_LUKS_CIPHER_ALG, .type = QEMU_OPT_STRING, .help = "Name of encryption cipher algorithm", }, { .name = BLOCK_CRYPTO_OPT_LUKS_CIPHER_MODE, .type = QEMU_OPT_STRING, .help = "Name of encryption cipher mode", }, { .name = BLOCK_CRYPTO_OPT_LUKS_IVGEN_ALG, .type = QEMU_OPT_STRING, .help = "Name of IV generator algorithm", }, { .name = BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG, .type = QEMU_OPT_STRING, .help = "Name of IV generator hash algorithm", }, { .name = BLOCK_CRYPTO_OPT_LUKS_HASH_ALG, .type = QEMU_OPT_STRING, .help = "Name of encryption hash algorithm", }, { /* end of list */ } }, }; static QCryptoBlockOpenOptions * block_crypto_open_opts_init(QCryptoBlockFormat format, QemuOpts *opts, Error **errp) { Visitor *v; QCryptoBlockOpenOptions *ret = NULL; Error *local_err = NULL; ret = g_new0(QCryptoBlockOpenOptions, 1); ret->format = format; v = opts_visitor_new(opts); visit_start_struct(v, NULL, NULL, 0, &local_err); if (local_err) { goto out; } switch (format) { case Q_CRYPTO_BLOCK_FORMAT_LUKS: visit_type_QCryptoBlockOptionsLUKS_members( v, &ret->u.luks, &local_err); break; default: error_setg(&local_err, "Unsupported block format %d", format); break; } if (!local_err) { visit_check_struct(v, &local_err); } visit_end_struct(v, NULL); out: if (local_err) { error_propagate(errp, local_err); qapi_free_QCryptoBlockOpenOptions(ret); ret = NULL; } visit_free(v); return ret; } static QCryptoBlockCreateOptions * block_crypto_create_opts_init(QCryptoBlockFormat format, QemuOpts *opts, Error **errp) { Visitor *v; QCryptoBlockCreateOptions *ret = NULL; Error *local_err = NULL; ret = g_new0(QCryptoBlockCreateOptions, 1); ret->format = format; v = opts_visitor_new(opts); visit_start_struct(v, NULL, NULL, 0, &local_err); if (local_err) { goto out; } switch (format) { case Q_CRYPTO_BLOCK_FORMAT_LUKS: visit_type_QCryptoBlockCreateOptionsLUKS_members( v, &ret->u.luks, &local_err); break; default: error_setg(&local_err, "Unsupported block format %d", format); break; } if (!local_err) { visit_check_struct(v, &local_err); } visit_end_struct(v, NULL); out: if (local_err) { error_propagate(errp, local_err); qapi_free_QCryptoBlockCreateOptions(ret); ret = NULL; } visit_free(v); return ret; } static int block_crypto_open_generic(QCryptoBlockFormat format, QemuOptsList *opts_spec, BlockDriverState *bs, QDict *options, int flags, Error **errp) { BlockCrypto *crypto = bs->opaque; QemuOpts *opts = NULL; Error *local_err = NULL; int ret = -EINVAL; QCryptoBlockOpenOptions *open_opts = NULL; unsigned int cflags = 0; opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, options, &local_err); if (local_err) { error_propagate(errp, local_err); goto cleanup; } open_opts = block_crypto_open_opts_init(format, opts, errp); if (!open_opts) { goto cleanup; } if (flags & BDRV_O_NO_IO) { cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; } crypto->block = qcrypto_block_open(open_opts, block_crypto_read_func, bs, cflags, errp); if (!crypto->block) { ret = -EIO; goto cleanup; } bs->encrypted = true; bs->valid_key = true; ret = 0; cleanup: qapi_free_QCryptoBlockOpenOptions(open_opts); return ret; } static int block_crypto_create_generic(QCryptoBlockFormat format, const char *filename, QemuOpts *opts, Error **errp) { int ret = -EINVAL; QCryptoBlockCreateOptions *create_opts = NULL; QCryptoBlock *crypto = NULL; struct BlockCryptoCreateData data = { .size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), BDRV_SECTOR_SIZE), .opts = opts, .filename = filename, }; create_opts = block_crypto_create_opts_init(format, opts, errp); if (!create_opts) { return -1; } crypto = qcrypto_block_create(create_opts, block_crypto_init_func, block_crypto_write_func, &data, errp); if (!crypto) { ret = -EIO; goto cleanup; } ret = 0; cleanup: qcrypto_block_free(crypto); blk_unref(data.blk); qapi_free_QCryptoBlockCreateOptions(create_opts); return ret; } static int block_crypto_truncate(BlockDriverState *bs, int64_t offset) { BlockCrypto *crypto = bs->opaque; size_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); offset += payload_offset; return bdrv_truncate(bs->file->bs, offset); } static void block_crypto_close(BlockDriverState *bs) { BlockCrypto *crypto = bs->opaque; qcrypto_block_free(crypto->block); } #define BLOCK_CRYPTO_MAX_SECTORS 32 static coroutine_fn int block_crypto_co_readv(BlockDriverState *bs, int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) { BlockCrypto *crypto = bs->opaque; int cur_nr_sectors; /* number of sectors in current iteration */ uint64_t bytes_done = 0; uint8_t *cipher_data = NULL; QEMUIOVector hd_qiov; int ret = 0; size_t payload_offset = qcrypto_block_get_payload_offset(crypto->block) / 512; qemu_iovec_init(&hd_qiov, qiov->niov); /* Bounce buffer so we have a linear mem region for * entire sector. XXX optimize so we avoid bounce * buffer in case that qiov->niov == 1 */ cipher_data = qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_SECTORS * 512, qiov->size)); if (cipher_data == NULL) { ret = -ENOMEM; goto cleanup; } while (remaining_sectors) { cur_nr_sectors = remaining_sectors; if (cur_nr_sectors > BLOCK_CRYPTO_MAX_SECTORS) { cur_nr_sectors = BLOCK_CRYPTO_MAX_SECTORS; } qemu_iovec_reset(&hd_qiov); qemu_iovec_add(&hd_qiov, cipher_data, cur_nr_sectors * 512); ret = bdrv_co_readv(bs->file, payload_offset + sector_num, cur_nr_sectors, &hd_qiov); if (ret < 0) { goto cleanup; } if (qcrypto_block_decrypt(crypto->block, sector_num, cipher_data, cur_nr_sectors * 512, NULL) < 0) { ret = -EIO; goto cleanup; } qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_nr_sectors * 512); remaining_sectors -= cur_nr_sectors; sector_num += cur_nr_sectors; bytes_done += cur_nr_sectors * 512; } cleanup: qemu_iovec_destroy(&hd_qiov); qemu_vfree(cipher_data); return ret; } static coroutine_fn int block_crypto_co_writev(BlockDriverState *bs, int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) { BlockCrypto *crypto = bs->opaque; int cur_nr_sectors; /* number of sectors in current iteration */ uint64_t bytes_done = 0; uint8_t *cipher_data = NULL; QEMUIOVector hd_qiov; int ret = 0; size_t payload_offset = qcrypto_block_get_payload_offset(crypto->block) / 512; qemu_iovec_init(&hd_qiov, qiov->niov); /* Bounce buffer so we have a linear mem region for * entire sector. XXX optimize so we avoid bounce * buffer in case that qiov->niov == 1 */ cipher_data = qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_SECTORS * 512, qiov->size)); if (cipher_data == NULL) { ret = -ENOMEM; goto cleanup; } while (remaining_sectors) { cur_nr_sectors = remaining_sectors; if (cur_nr_sectors > BLOCK_CRYPTO_MAX_SECTORS) { cur_nr_sectors = BLOCK_CRYPTO_MAX_SECTORS; } qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_nr_sectors * 512); if (qcrypto_block_encrypt(crypto->block, sector_num, cipher_data, cur_nr_sectors * 512, NULL) < 0) { ret = -EIO; goto cleanup; } qemu_iovec_reset(&hd_qiov); qemu_iovec_add(&hd_qiov, cipher_data, cur_nr_sectors * 512); ret = bdrv_co_writev(bs->file, payload_offset + sector_num, cur_nr_sectors, &hd_qiov); if (ret < 0) { goto cleanup; } remaining_sectors -= cur_nr_sectors; sector_num += cur_nr_sectors; bytes_done += cur_nr_sectors * 512; } cleanup: qemu_iovec_destroy(&hd_qiov); qemu_vfree(cipher_data); return ret; } static int64_t block_crypto_getlength(BlockDriverState *bs) { BlockCrypto *crypto = bs->opaque; int64_t len = bdrv_getlength(bs->file->bs); ssize_t offset = qcrypto_block_get_payload_offset(crypto->block); len -= offset; return len; } static int block_crypto_probe_luks(const uint8_t *buf, int buf_size, const char *filename) { return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, buf, buf_size, filename); } static int block_crypto_open_luks(BlockDriverState *bs, QDict *options, int flags, Error **errp) { return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, &block_crypto_runtime_opts_luks, bs, options, flags, errp); } static int block_crypto_create_luks(const char *filename, QemuOpts *opts, Error **errp) { return block_crypto_create_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, filename, opts, errp); } BlockDriver bdrv_crypto_luks = { .format_name = "luks", .instance_size = sizeof(BlockCrypto), .bdrv_probe = block_crypto_probe_luks, .bdrv_open = block_crypto_open_luks, .bdrv_close = block_crypto_close, .bdrv_create = block_crypto_create_luks, .bdrv_truncate = block_crypto_truncate, .create_opts = &block_crypto_create_opts_luks, .bdrv_co_readv = block_crypto_co_readv, .bdrv_co_writev = block_crypto_co_writev, .bdrv_getlength = block_crypto_getlength, }; static void block_crypto_init(void) { bdrv_register(&bdrv_crypto_luks); } block_init(block_crypto_init);