From 35286daeca43444aa1a9c7a36ffc499877eb6668 Mon Sep 17 00:00:00 2001 From: Hyman Huang Date: Tue, 30 Jan 2024 13:37:23 +0800 Subject: [PATCH] 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 ++++- block/crypto.c | 12 ++++++++++-- block/crypto.h | 8 ++++++++ qapi/crypto.json | 5 ++++- 4 files changed, 26 insertions(+), 4 deletions(-) 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; } diff --git a/block/crypto.c b/block/crypto.c index 8e7ee5e9ac..21eed909c1 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -231,6 +231,7 @@ static QemuOptsList block_crypto_create_opts_luks = { BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""), BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""), BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), + BLOCK_CRYPTO_OPT_DEF_LUKS_DETACHED_HEADER(""), { /* end of list */ } }, }; @@ -405,7 +406,7 @@ block_crypto_co_create_generic(BlockDriverState *bs, int64_t size, data = (struct BlockCryptoCreateData) { .blk = blk, - .size = size, + .size = flags & QCRYPTO_BLOCK_CREATE_DETACHED ? 0 : size, .prealloc = prealloc, }; @@ -791,6 +792,9 @@ block_crypto_co_create_opts_luks(BlockDriver *drv, const char *filename, PreallocMode prealloc; char *buf = NULL; int64_t size; + bool detached_hdr = + qemu_opt_get_bool(opts, "detached-header", false); + unsigned int cflags = 0; int ret; Error *local_err = NULL; @@ -830,9 +834,13 @@ block_crypto_co_create_opts_luks(BlockDriver *drv, const char *filename, goto fail; } + if (detached_hdr) { + cflags |= QCRYPTO_BLOCK_CREATE_DETACHED; + } + /* Create format layer */ ret = block_crypto_co_create_generic(bs, size, create_opts, - prealloc, 0, errp); + prealloc, cflags, errp); if (ret < 0) { goto fail; } diff --git a/block/crypto.h b/block/crypto.h index 72e792c9af..dc3d2d5ed9 100644 --- a/block/crypto.h +++ b/block/crypto.h @@ -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, \ diff --git a/qapi/crypto.json b/qapi/crypto.json index 2f2aeff5fd..22c6cce3ae 100644 --- a/qapi/crypto.json +++ b/qapi/crypto.json @@ -226,6 +226,8 @@ # @iter-time: number of milliseconds to spend in PBKDF passphrase # processing. Currently defaults to 2000. (since 2.8) # +# @detached-header: create a detached LUKS header. (since 9.0) +# # Since: 2.6 ## { 'struct': 'QCryptoBlockCreateOptionsLUKS', @@ -235,7 +237,8 @@ '*ivgen-alg': 'QCryptoIVGenAlgorithm', '*ivgen-hash-alg': 'QCryptoHashAlgorithm', '*hash-alg': 'QCryptoHashAlgorithm', - '*iter-time': 'int'}} + '*iter-time': 'int', + '*detached-header': 'bool'}} ## # @QCryptoBlockOpenOptions: