block/crypto.c - qemu - Git at Google

 /*
  * 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);
	/*
	* 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);