block: Support detached LUKS header creation using blockdev-create
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>
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 77d1f50..e4ef36d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -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' } }
