The qemu-img info command has the ability to expose format specific metadata about volumes. Wire up this facility for the LUKS driver to report on cipher configuration and key slot usage.
$ qemu-img info ~/VirtualMachines/demo.luks image: /home/berrange/VirtualMachines/demo.luks file format: luks virtual size: 98M (102760448 bytes) disk size: 100M encrypted: yes Format specific information: ivgen alg: plain64 hash alg: sha1 cipher alg: aes-128 uuid: 6ddee74b-3a22-408c-8909-6789d4fa2594 cipher mode: xts slots: [0]: active: true iters: 572706 key offset: 4096 stripes: 4000 [1]: active: false key offset: 135168 [2]: active: false key offset: 266240 [3]: active: false key offset: 397312 [4]: active: false key offset: 528384 [5]: active: false key offset: 659456 [6]: active: false key offset: 790528 [7]: active: false key offset: 921600 payload offset: 2097152 master key iters: 142375 One somewhat undesirable artifact is that the data fields are printed out in (apparently) random order. This will be addressed later by changing the way the block layer pretty-prints the image specific data. Signed-off-by: Daniel P. Berrange <berra...@redhat.com> --- block/crypto.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ qapi/block-core.json | 6 +++++- 2 files changed, 54 insertions(+), 1 deletion(-) diff --git a/block/crypto.c b/block/crypto.c index 7eaa057..7f61e12 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -563,6 +563,53 @@ static int block_crypto_create_luks(const char *filename, filename, opts, errp); } +static int block_crypto_get_info_luks(BlockDriverState *bs, + BlockDriverInfo *bdi) +{ + BlockDriverInfo subbdi; + int ret; + + ret = bdrv_get_info(bs->file->bs, &subbdi); + if (ret != 0) { + return ret; + } + + bdi->unallocated_blocks_are_zero = false; + bdi->can_write_zeroes_with_unmap = false; + bdi->cluster_size = subbdi.cluster_size; + + return 0; +} + +static ImageInfoSpecific * +block_crypto_get_specific_info_luks(BlockDriverState *bs) +{ + BlockCrypto *crypto = bs->opaque; + ImageInfoSpecific *spec_info; + QCryptoBlockInfo *info; + + info = qcrypto_block_get_info(crypto->block, NULL); + if (!info) { + return NULL; + } + if (info->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) { + qapi_free_QCryptoBlockInfo(info); + return NULL; + } + + spec_info = g_new(ImageInfoSpecific, 1); + spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; + spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); + *spec_info->u.luks.data = info->u.luks; + + /* Blank out pointers we've just stolen to avoid double free */ + memset(&info->u.luks, 0, sizeof(info->u.luks)); + + qapi_free_QCryptoBlockInfo(info); + + return spec_info; +} + BlockDriver bdrv_crypto_luks = { .format_name = "luks", .instance_size = sizeof(BlockCrypto), @@ -576,6 +623,8 @@ BlockDriver bdrv_crypto_luks = { .bdrv_co_readv = block_crypto_co_readv, .bdrv_co_writev = block_crypto_co_writev, .bdrv_getlength = block_crypto_getlength, + .bdrv_get_info = block_crypto_get_info_luks, + .bdrv_get_specific_info = block_crypto_get_specific_info_luks, }; static void block_crypto_init(void) diff --git a/qapi/block-core.json b/qapi/block-core.json index f462345..d4bab5d 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -85,7 +85,11 @@ { 'union': 'ImageInfoSpecific', 'data': { 'qcow2': 'ImageInfoSpecificQCow2', - 'vmdk': 'ImageInfoSpecificVmdk' + 'vmdk': 'ImageInfoSpecificVmdk', + # If we need to add block driver specific parameters for + # LUKS in future, then we'll subclass QCryptoBlockInfoLUKS + # to define a ImageInfoSpecificLUKS + 'luks': 'QCryptoBlockInfoLUKS' } } ## -- 2.7.4