On Tue, Jun 14, 2016 at 05:49:24PM +0200, Max Reitz wrote:
> On 14.06.2016 17:47, Daniel P. Berrange wrote:
> > On Tue, Jun 14, 2016 at 05:38:36PM +0200, Max Reitz wrote:
> >> On 14.06.2016 12:56, Daniel P. Berrange wrote:
> >>> 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 | 59
> >>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>> qapi/block-core.json | 7 ++++++-
> >>> 2 files changed, 65 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/block/crypto.c b/block/crypto.c
> >>> index 758e14e..823572f 100644
> >>> --- a/block/crypto.c
> >>> +++ b/block/crypto.c
> >>> @@ -565,6 +565,63 @@ 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;
> >>
> >> One space too many.
> >>
> >>> + spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
> >>> + spec_info->u.luks.data->cipher_alg = info->u.luks.cipher_alg;
> >>> + spec_info->u.luks.data->cipher_mode = info->u.luks.cipher_mode;
> >>> + spec_info->u.luks.data->ivgen_alg = info->u.luks.ivgen_alg;
> >>> + spec_info->u.luks.data->has_ivgen_hash_alg =
> >>> + info->u.luks.has_ivgen_hash_alg;
> >>> + spec_info->u.luks.data->ivgen_hash_alg = info->u.luks.ivgen_hash_alg;
> >>> + spec_info->u.luks.data->hash_alg = info->u.luks.hash_alg;
> >>> + spec_info->u.luks.data->payload_offset = info->u.luks.payload_offset;
> >>> + spec_info->u.luks.data->master_key_iters =
> >>> info->u.luks.master_key_iters;
> >>> + spec_info->u.luks.data->uuid = g_strdup(info->u.luks.uuid);
> >>> +
> >>> + /* Steal the pointer instead of bothering to copy */
> >>> + spec_info->u.luks.data->slots = info->u.luks.slots;
> >>> + info->u.luks.slots = NULL;
> >>
> >> Why not just steal everything by *spec_info->u.luks.data = info->u.luks
> >> and then making sure the qapi_free() call below won't free anything in
> >> there with a memset(&info->u.luks, 0, sizeof(info->u.luks))?
> >
> > I wish we could, but info->u.luks is an embedded QCryptoBlockInfoLUKS,
> > not merely a pointer to an independently allocated QCryptoBlockInfoLUKS :-(
>
> Yes, but note the asterisk I put there. Leave the g_new() and just make it:
>
> spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
> *spec_info->u.luks.data = info->u.luks;
Oh whoops, I mis-read your original reply. I see what you mean now.
Regards,
Daniel
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