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block: Support detached LUKS header creation using blockdev-create

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Firstly, enable the ability to choose the block device containing
a detachable LUKS header by adding the 'header' parameter to
BlockdevCreateOptionsLUKS.

Secondly, when formatting the LUKS volume with a detachable header,
truncate the payload volume to length without a header size.

Using the qmp blockdev command, create the LUKS volume with a
detachable header as follows:

1. add the secret to lock/unlock the cipher stored in the
   detached LUKS header
$ virsh qemu-monitor-command vm '{"execute":"object-add",
> "arguments":{"qom-type": "secret", "id": "sec0", "data": "foo"}}'

2. create a header img with 0 size
$ virsh qemu-monitor-command vm '{"execute":"blockdev-create",
> "arguments":{"job-id":"job0", "options":{"driver":"file",
> "filename":"/path/to/detached_luks_header.img", "size":0 }}}'

3. add protocol blockdev node for header
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments": {"driver":"file", "filename":
> "/path/to/detached_luks_header.img", "node-name":
> "detached-luks-header-storage"}}'

4. create a payload img with 0 size
$ virsh qemu-monitor-command vm '{"execute":"blockdev-create",
> "arguments":{"job-id":"job1", "options":{"driver":"file",
> "filename":"/path/to/detached_luks_payload_raw.img", "size":0}}}'

5. add protocol blockdev node for payload
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments": {"driver":"file", "filename":
> "/path/to/detached_luks_payload_raw.img", "node-name":
> "luks-payload-raw-storage"}}'

6. do the formatting with 128M size
$ virsh qemu-monitor-command c81_node1 '{"execute":"blockdev-create",
> "arguments":{"job-id":"job2", "options":{"driver":"luks", "header":
> "detached-luks-header-storage", "file":"luks-payload-raw-storage",
> "size":134217728, "preallocation":"full", "key-secret":"sec0" }}}'

Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Hyman Huang 2024-01-30 13:37:22 +08:00 committed by Daniel P. Berrangé
parent d74523a3b3
commit d0112eb415
2 changed files with 96 additions and 8 deletions
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101
block/crypto.c
View File

@ -162,6 +162,48 @@ error:
return ret;
}
static int coroutine_fn GRAPH_UNLOCKED
block_crypto_co_format_luks_payload(BlockdevCreateOptionsLUKS *luks_opts,
Error **errp)
{
BlockDriverState *bs = NULL;
BlockBackend *blk = NULL;
Error *local_error = NULL;
int ret;
if (luks_opts->size > INT64_MAX) {
return -EFBIG;
}
bs = bdrv_co_open_blockdev_ref(luks_opts->file, errp);
if (bs == NULL) {
return -EIO;
}
blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
BLK_PERM_ALL, errp);
if (!blk) {
ret = -EPERM;
goto fail;
}
ret = blk_truncate(blk, luks_opts->size, true,
luks_opts->preallocation, 0, &local_error);
if (ret < 0) {
if (ret == -EFBIG) {
/* Replace the error message with a better one */
error_free(local_error);
error_setg(errp, "The requested file size is too large");
}
goto fail;
}
ret = 0;
fail:
bdrv_co_unref(bs);
return ret;
}
static QemuOptsList block_crypto_runtime_opts_luks = {
.name = "crypto",
@ -341,7 +383,9 @@ static int block_crypto_open_generic(QCryptoBlockFormat format,
static int coroutine_fn GRAPH_UNLOCKED
block_crypto_co_create_generic(BlockDriverState *bs, int64_t size,
QCryptoBlockCreateOptions *opts,
PreallocMode prealloc, Error **errp)
PreallocMode prealloc,
unsigned int flags,
Error **errp)
{
int ret;
BlockBackend *blk;
@ -369,7 +413,7 @@ block_crypto_co_create_generic(BlockDriverState *bs, int64_t size,
block_crypto_create_init_func,
block_crypto_create_write_func,
&data,
0,
flags,
errp);
if (!crypto) {
@ -656,16 +700,26 @@ static int coroutine_fn GRAPH_UNLOCKED
block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
{
BlockdevCreateOptionsLUKS *luks_opts;
BlockDriverState *hdr_bs = NULL;
BlockDriverState *bs = NULL;
QCryptoBlockCreateOptions create_opts;
PreallocMode preallocation = PREALLOC_MODE_OFF;
unsigned int cflags = 0;
int ret;
assert(create_options->driver == BLOCKDEV_DRIVER_LUKS);
luks_opts = &create_options->u.luks;
if (luks_opts->file == NULL) {
error_setg(errp, "Formatting LUKS disk requires parameter 'file'");
if (luks_opts->header == NULL && luks_opts->file == NULL) {
error_setg(errp, "Either the parameter 'header' or 'file' must "
"be specified");
return -EINVAL;
}
if ((luks_opts->preallocation != PREALLOC_MODE_OFF) &&
(luks_opts->file == NULL)) {
error_setg(errp, "Parameter 'preallocation' requires 'file' to be "
"specified for formatting LUKS disk");
return -EINVAL;
}
@ -678,14 +732,38 @@ block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
preallocation = luks_opts->preallocation;
}
if (luks_opts->file) {
if (luks_opts->header) {
/* LUKS volume with detached header */
hdr_bs = bdrv_co_open_blockdev_ref(luks_opts->header, errp);
if (hdr_bs == NULL) {
return -EIO;
}
cflags |= QCRYPTO_BLOCK_CREATE_DETACHED;
/* Format the LUKS header node */
ret = block_crypto_co_create_generic(hdr_bs, 0, &create_opts,
PREALLOC_MODE_OFF, cflags, errp);
if (ret < 0) {
goto fail;
}
/* Format the LUKS payload node */
if (luks_opts->file) {
ret = block_crypto_co_format_luks_payload(luks_opts, errp);
if (ret < 0) {
goto fail;
}
}
} else if (luks_opts->file) {
/* LUKS volume with none-detached header */
bs = bdrv_co_open_blockdev_ref(luks_opts->file, errp);
if (bs == NULL) {
return -EIO;
}
ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
preallocation, errp);
preallocation, cflags, errp);
if (ret < 0) {
goto fail;
}
@ -693,7 +771,13 @@ block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
ret = 0;
fail:
bdrv_co_unref(bs);
if (hdr_bs != NULL) {
bdrv_co_unref(hdr_bs);
}
if (bs != NULL) {
bdrv_co_unref(bs);
}
return ret;
}
@ -747,7 +831,8 @@ block_crypto_co_create_opts_luks(BlockDriver *drv, const char *filename,
}
/* Create format layer */
ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp);
ret = block_crypto_co_create_generic(bs, size, create_opts,
prealloc, 0, errp);
if (ret < 0) {
goto fail;
}

3
qapi/block-core.json
View File

@ -4958,6 +4958,8 @@
# @file: Node to create the image format on, mandatory except when
# 'preallocation' is not requested
#
# @header: Block device holding a detached LUKS header. (since 9.0)
#
# @size: Size of the virtual disk in bytes
#
# @preallocation: Preallocation mode for the new image (since: 4.2)
@ -4968,6 +4970,7 @@
{ 'struct': 'BlockdevCreateOptionsLUKS',
'base': 'QCryptoBlockCreateOptionsLUKS',
'data': { '*file': 'BlockdevRef',
'*header': 'BlockdevRef',
'size': 'size',
'*preallocation': 'PreallocMode' } }