On Mon, Aug 26, 2019 at 04:51:00PM +0300, Maxim Levitsky wrote:
> This function will be used later to store
> new keys to the luks metadata
>
> Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
> ---
> crypto/block-luks.c | 310 ++++++++++++++++++++++++++------------------
> 1 file changed, 184 insertions(+), 126 deletions(-)
>
> diff --git a/crypto/block-luks.c b/crypto/block-luks.c
> index cc9a52c9af..d713125925 100644
> --- a/crypto/block-luks.c
> +++ b/crypto/block-luks.c
> @@ -650,6 +650,176 @@ out:
>
> }
>
> +/*
> + * Given a key slot, user password, and the master key,
> + * will store the encrypted master key there, and update the
> + * in-memory header. User must then write the in-memory header
> + *
> + * Returns:
> + * 0 if the keyslot was written successfully
> + * with the provided password
> + * -1 if a fatal error occurred while storing the key
> + */
> +static int
> +qcrypto_block_luks_store_key(QCryptoBlock *block,
> + unsigned int slot_idx,
> + const char *password,
> + uint8_t *masterkey,
> + uint64_t iter_time,
> + QCryptoBlockWriteFunc writefunc,
> + void *opaque,
> + Error **errp)
> +{
> + QCryptoBlockLUKS *luks = block->opaque;
> + QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx];
> + g_autofree uint8_t *splitkey = NULL;
> + size_t splitkeylen;
> + g_autofree uint8_t *slotkey = NULL;
> + g_autoptr(QCryptoCipher) cipher = NULL;
> + g_autoptr(QCryptoIVGen) ivgen = NULL;
> + Error *local_err = NULL;
> + uint64_t iters;
> + int ret = -1;
> +
> + if (qcrypto_random_bytes(slot->salt,
> + QCRYPTO_BLOCK_LUKS_SALT_LEN,
> + errp) < 0) {
> + goto cleanup;
> + }
> +
> + splitkeylen = luks->header.master_key_len * slot->stripes;
> +
> + /*
> + * Determine how many iterations are required to
> + * hash the user password while consuming 1 second of compute
> + * time
> + */
> + iters = qcrypto_pbkdf2_count_iters(luks->hash_alg,
> + (uint8_t *)password, strlen(password),
> + slot->salt,
> + QCRYPTO_BLOCK_LUKS_SALT_LEN,
> + luks->header.master_key_len,
> + &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + goto cleanup;
> + }
> +
> + if (iters > (ULLONG_MAX / iter_time)) {
> + error_setg_errno(errp, ERANGE,
> + "PBKDF iterations %llu too large to scale",
> + (unsigned long long)iters);
> + goto cleanup;
> + }
> +
> + /* iter_time was in millis, but count_iters reported for secs */
> + iters = iters * iter_time / 1000;
> +
> + if (iters > UINT32_MAX) {
> + error_setg_errno(errp, ERANGE,
> + "PBKDF iterations %llu larger than %u",
> + (unsigned long long)iters, UINT32_MAX);
> + goto cleanup;
> + }
> +
> + slot->iterations =
> + MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
> +
> +
> + /*
> + * Generate a key that we'll use to encrypt the master
> + * key, from the user's password
> + */
> + slotkey = g_new0(uint8_t, luks->header.master_key_len);
> + if (qcrypto_pbkdf2(luks->hash_alg,
> + (uint8_t *)password, strlen(password),
> + slot->salt,
> + QCRYPTO_BLOCK_LUKS_SALT_LEN,
> + slot->iterations,
> + slotkey, luks->header.master_key_len,
> + errp) < 0) {
> + goto cleanup;
> + }
> +
> +
> + /*
> + * Setup the encryption objects needed to encrypt the
> + * master key material
> + */
> + cipher = qcrypto_cipher_new(luks->cipher_alg,
> + luks->cipher_mode,
> + slotkey, luks->header.master_key_len,
> + errp);
> + if (!cipher) {
> + goto cleanup;
> + }
> +
> + ivgen = qcrypto_ivgen_new(luks->ivgen_alg,
> + luks->ivgen_cipher_alg,
> + luks->ivgen_hash_alg,
> + slotkey, luks->header.master_key_len,
> + errp);
> + if (!ivgen) {
> + goto cleanup;
> + }
> +
> + /*
> + * Before storing the master key, we need to vastly
> + * increase its size, as protection against forensic
> + * disk data recovery
> + */
> + splitkey = g_new0(uint8_t, splitkeylen);
> +
> + if (qcrypto_afsplit_encode(luks->hash_alg,
> + luks->header.master_key_len,
> + slot->stripes,
> + masterkey,
> + splitkey,
> + errp) < 0) {
> + goto cleanup;
> + }
> +
> + /*
> + * Now we encrypt the split master key with the key generated
> + * from the user's password, before storing it
> + */
> + if (qcrypto_block_cipher_encrypt_helper(cipher, block->niv, ivgen,
> + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
> + 0,
> + splitkey,
> + splitkeylen,
> + errp) < 0) {
> + goto cleanup;
> + }
> +
> + /* Write out the slot's master key material. */
> + if (writefunc(block,
> + slot->key_offset_sector *
> + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
> + splitkey, splitkeylen,
> + opaque,
> + errp) != splitkeylen) {
> + goto cleanup;
> + }
> +
> + slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED;
> +
> + if (qcrypto_block_luks_store_header(block, writefunc, opaque, errp)) {
Check < 0
> + goto cleanup;
> + }
> +
> + ret = 0;
> +
> +cleanup:
> + if (slotkey) {
> + memset(slotkey, 0, luks->header.master_key_len);
> + }
> + if (splitkey) {
> + memset(splitkey, 0, splitkeylen);
> + }
> + return ret;
> +}
> +
> + /* populate the slot 0 with the password encrypted master key*/
> + /* This will also store the header */
> + if (qcrypto_block_luks_store_key(block,
> + 0,
> + password,
> + masterkey,
> + luks_opts.iter_time,
> + writefunc,
> + opaque,
> + errp)) {
> goto error;
Check < 0
> - }
> + }
Indent off by one
>
> - memset(masterkey, 0, luks->header.master_key_len);
> - memset(slotkey, 0, luks->header.master_key_len);
>
> + memset(masterkey, 0, luks->header.master_key_len);
> return 0;
The blank line was moved by accident.
>
> error:
> if (masterkey) {
> memset(masterkey, 0, luks->header.master_key_len);
> }
> - if (slotkey) {
> - memset(slotkey, 0, luks->header.master_key_len);
> - }
>
>
Regards,
Daniel
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