mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
0cebabd5e8
qemu/block/crypto.c
Daniel P. Berrange c7c4cf498f block: export LUKS specific data to qemu-img info 
The qemu-img info command has the ability to expose format
specific metadata about volumes. Wire up this facility for
the LUKS driver to report on cipher configuration and key
slot usage.

    $ qemu-img info ~/VirtualMachines/demo.luks
    image: /home/berrange/VirtualMachines/demo.luks
    file format: luks
    virtual size: 98M (102760448 bytes)
    disk size: 100M
    encrypted: yes
    Format specific information:
        ivgen alg: plain64
        hash alg: sha1
        cipher alg: aes-128
        uuid: 6ddee74b-3a22-408c-8909-6789d4fa2594
        cipher mode: xts
        slots:
            [0]:
                active: true
                iters: 572706
                key offset: 4096
                stripes: 4000
            [1]:
                active: false
                key offset: 135168
            [2]:
                active: false
                key offset: 266240
            [3]:
                active: false
                key offset: 397312
            [4]:
                active: false
                key offset: 528384
            [5]:
                active: false
                key offset: 659456
            [6]:
                active: false
                key offset: 790528
            [7]:
                active: false
                key offset: 921600
        payload offset: 2097152
        master key iters: 142375

One somewhat undesirable artifact is that the data fields are
printed out in (apparently) random order. This will be addressed
later by changing the way the block layer pretty-prints the
image specific data.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1469192015-16487-3-git-send-email-berrange@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-07-26 17:46:37 +02:00

636 lines
18 KiB
C
Raw Blame History

/*
* 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);
}
static int block_crypto_get_info_luks(BlockDriverState *bs,
BlockDriverInfo *bdi)
{
BlockDriverInfo subbdi;
int ret;
ret = bdrv_get_info(bs->file->bs, &subbdi);
if (ret != 0) {
return ret;
}
bdi->unallocated_blocks_are_zero = false;
bdi->can_write_zeroes_with_unmap = false;
bdi->cluster_size = subbdi.cluster_size;
return 0;
}
static ImageInfoSpecific *
block_crypto_get_specific_info_luks(BlockDriverState *bs)
{
BlockCrypto *crypto = bs->opaque;
ImageInfoSpecific *spec_info;
QCryptoBlockInfo *info;
info = qcrypto_block_get_info(crypto->block, NULL);
if (!info) {
return NULL;
}
if (info->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) {
qapi_free_QCryptoBlockInfo(info);
return NULL;
}
spec_info = g_new(ImageInfoSpecific, 1);
spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
*spec_info->u.luks.data = info->u.luks;
/* Blank out pointers we've just stolen to avoid double free */
memset(&info->u.luks, 0, sizeof(info->u.luks));
qapi_free_QCryptoBlockInfo(info);
return spec_info;
}
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,
.bdrv_get_info = block_crypto_get_info_luks,
.bdrv_get_specific_info = block_crypto_get_specific_info_luks,
};
static void block_crypto_init(void)
{
bdrv_register(&bdrv_crypto_luks);
}
block_init(block_crypto_init);
Reference in New Issue View Git Blame Copy Permalink