On Mon, Aug 26, 2019 at 04:51:01PM +0300, Maxim Levitsky wrote:
> Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
> ---
> crypto/block-luks.c | 64 +++++++++++++++++++++++++++++----------------
> 1 file changed, 41 insertions(+), 23 deletions(-)
>
> diff --git a/crypto/block-luks.c b/crypto/block-luks.c
> index d713125925..6a43d97ce5 100644
> --- a/crypto/block-luks.c
> +++ b/crypto/block-luks.c
> @@ -409,6 +409,32 @@ qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm
> cipher,
> }
> }
>
> +/*
> + * Returns number of sectors needed to store the key material
> + * given number of anti forensic stripes
> + */
> +static int
> +qcrypto_block_luks_splitkeylen_sectors(const QCryptoBlockLUKS *luks,
> + unsigned int stripes)
> +{
> + /*
> + * This calculation doesn't match that shown in the spec,
> + * but instead follows the cryptsetup implementation.
> + */
> +
> + size_t header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
The caller already calculated that so just pass it in
> +
> + size_t splitkeylen = luks->header.master_key_len * stripes;
> +
> + /* First align the key material size to block size*/
> + size_t splitkeylen_sectors =
> + DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE);
> +
> + /* Then also align the key material size to the size of the header */
> + return ROUND_UP(splitkeylen_sectors, header_sectors);
> +}
> +
> /*
> * Stores the main LUKS header, taking care of endianess
> */
> @@ -1151,7 +1177,8 @@ qcrypto_block_luks_create(QCryptoBlock *block,
> QCryptoBlockCreateOptionsLUKS luks_opts;
> Error *local_err = NULL;
> g_autofree uint8_t *masterkey = NULL;
> - size_t splitkeylen = 0;
> + size_t header_sectors;
> + size_t split_key_sectors;
> size_t i;
> g_autofree char *password;
> const char *cipher_alg;
> @@ -1370,37 +1397,28 @@ qcrypto_block_luks_create(QCryptoBlock *block,
> goto error;
> }
>
> + /* start with the sector that follows the header*/
> + header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
> +
> + split_key_sectors =
> + qcrypto_block_luks_splitkeylen_sectors(luks,
> + QCRYPTO_BLOCK_LUKS_STRIPES);
>
> - /* Although LUKS has multiple key slots, we're just going
> - * to use the first key slot */
> - splitkeylen = luks->header.master_key_len * QCRYPTO_BLOCK_LUKS_STRIPES;
> for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
> - luks->header.key_slots[i].active =
> QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
> - luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
> + QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[i];
> + slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
>
> - /* This calculation doesn't match that shown in the spec,
> - * but instead follows the cryptsetup implementation.
> - */
> - luks->header.key_slots[i].key_offset_sector =
> - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
> - (ROUND_UP(DIV_ROUND_UP(splitkeylen,
> QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
> - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
> + slot->key_offset_sector = header_sectors + i * split_key_sectors;
> + slot->stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
> }
>
> -
> /* The total size of the LUKS headers is the partition header + key
> * slot headers, rounded up to the nearest sector, combined with
> * the size of each master key material region, also rounded up
> * to the nearest sector */
> - luks->header.payload_offset_sector =
> - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
> - (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
> - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
> - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
> - QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
> + luks->header.payload_offset_sector = header_sectors +
> + QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS * split_key_sectors;
>
> block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
> block->payload_offset = luks->header.payload_offset_sector *
Reviewed-by: Daniel P. Berrangé <berra...@redhat.com>
Regards,
Daniel
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