v2:
- Simplify the design by reusing the LUKS driver to implement
the generic Luks encryption, thank Daniel for the insightful
advice.
- rebase on master.
This functionality was motivated by the following to-do list seen
in crypto documents:
https://wiki.qemu.org/Features/Block/Crypto
The last chapter says we should "separate header volume":
The LUKS format has ability to store the header in a separate volume
from the payload. We should extend the LUKS driver in QEMU to support
this use case.
By enhancing the LUKS driver, it is possible to enable
the detachable LUKS header and, as a result, achieve
general encryption for any disk format that QEMU has
supported.
Take the qcow2 as an example, the usage of the generic
LUKS encryption as follows:
1. add a protocol blockdev node of data disk
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments":{"node-name":"libvirt-1-storage", "driver":"file",
> "filename":"/path/to/test_disk.qcow2"}}'
2. add a protocol blockdev node of LUKS header as above.
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments":{"node-name":"libvirt-2-storage", "driver":"file",
> "filename": "/path/to/cipher.gluks" }}'
3. add the secret for decrypting the cipher stored in LUKS
header above
$ virsh qemu-monitor-command vm '{"execute":"object-add",
> "arguments":{"qom-type":"secret", "id":
> "libvirt-2-storage-secret0", "data":"abc123"}}'
4. add the qcow2-drived blockdev format node
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments":{"node-name":"libvirt-1-format", "driver":"qcow2",
> "file":"libvirt-1-storage"}}'
5. add the luks-drived blockdev to link the qcow2 disk with
LUKS header by specifying the field "header"
$ virsh qemu-monitor-command vm '{"execute":"blockdev-add",
> "arguments":{"node-name":"libvirt-2-format", "driver":"luks",
> "file":"libvirt-1-format", "header":"libvirt-2-storage",
> "key-secret":"libvirt-2-format-secret0"}}'
6. add the virtio-blk device finally
$ virsh qemu-monitor-command vm '{"execute":"device_add",
> "arguments": {"num-queues":"1", "driver":"virtio-blk-pci",
> "drive": "libvirt-2-format", "id":"virtio-disk2"}}'
The generic LUKS encryption method of starting a virtual
machine (VM) is somewhat similar to hot-plug in that both
maintaining the same json command while the starting VM
changes the "blockdev-add/device_add" parameters to
"blockdev/device".
Please review, thanks
Best regared,
Yong
Hyman Huang (4):
crypto: Introduce option and structure for detached LUKS header
crypto: Introduce payload offset set function
crypto: Support generic LUKS encryption
block: Support detached LUKS header creation for blockdev-create
block/crypto.c | 47 ++++++++++++++++++++++++++++++++++++++++--
crypto/block.c | 4 ++++
include/crypto/block.h | 1 +
qapi/block-core.json | 11 ++++++++--
4 files changed, 59 insertions(+), 4 deletions(-)
--
2.39.1