block: Support detached LUKS header creation using qemu-img

Even though a LUKS header might be created with cryptsetup,
qemu-img should be enhanced to accommodate it as well.

Add the 'detached-header' option to specify the creation of
a detached LUKS header. This is how it is used:
$ qemu-img create --object secret,id=sec0,data=abc123 -f luks
> -o cipher-alg=aes-256,cipher-mode=xts -o key-secret=sec0
> -o detached-header=true header.luks

Using qemu-img or cryptsetup tools to query information of
an LUKS header image as follows:

Assume a detached LUKS header image has been created by:
$ dd if=/dev/zero of=test-header.img bs=1M count=32
$ dd if=/dev/zero of=test-payload.img bs=1M count=1000
$ cryptsetup luksFormat --header test-header.img test-payload.img
> --force-password --type luks1

Header image information could be queried using cryptsetup:
$ cryptsetup luksDump test-header.img

or qemu-img:
$ qemu-img info 'json:{"driver":"luks","file":{"filename":
> "test-payload.img"},"header":{"filename":"test-header.img"}}'

When using qemu-img, keep in mind that the entire disk
information specified by the JSON-format string above must be
supplied on the commandline; if not, an overlay check will reveal
a problem with the LUKS volume check logic.

Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[changed to pass 'cflags' to block_crypto_co_create_generic]
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Hyman Huang 2024-01-30 13:37:23 +08:00 committed by Daniel P. Berrangé
parent d0112eb415
commit 35286daeca
4 changed files with 26 additions and 4 deletions

View file

@ -41,6 +41,7 @@
#define BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG "ivgen-hash-alg"
#define BLOCK_CRYPTO_OPT_LUKS_HASH_ALG "hash-alg"
#define BLOCK_CRYPTO_OPT_LUKS_ITER_TIME "iter-time"
#define BLOCK_CRYPTO_OPT_LUKS_DETACHED_HEADER "detached-header"
#define BLOCK_CRYPTO_OPT_LUKS_KEYSLOT "keyslot"
#define BLOCK_CRYPTO_OPT_LUKS_STATE "state"
#define BLOCK_CRYPTO_OPT_LUKS_OLD_SECRET "old-secret"
@ -100,6 +101,13 @@
.help = "Select new state of affected keyslots (active/inactive)",\
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_DETACHED_HEADER(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_DETACHED_HEADER, \
.type = QEMU_OPT_BOOL, \
.help = "Create a detached LUKS header", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_KEYSLOT, \