From 35286daeca43444aa1a9c7a36ffc499877eb6668 Mon Sep 17 00:00:00 2001 From: Hyman Huang Date: Tue, 30 Jan 2024 13:37:23 +0800 Subject: block: Support detached LUKS header creation using qemu-img MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Daniel P. Berrangé [changed to pass 'cflags' to block_crypto_co_create_generic] Signed-off-by: Daniel P. Berrangé --- block.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'block.c') diff --git a/block.c b/block.c index 30afdcbba6..1ed9214f66 100644 --- a/block.c +++ b/block.c @@ -7357,7 +7357,10 @@ void bdrv_img_create(const char *filename, const char *fmt, goto out; } - if (size == -1) { + /* Parameter 'size' is not needed for detached LUKS header */ + if (size == -1 && + !(!strcmp(fmt, "luks") && + qemu_opt_get_bool(opts, "detached-header", false))) { error_setg(errp, "Image creation needs a size parameter"); goto out; } -- cgit 1.4.1