Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
---
crypto/block-luks.c | 356 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 354 insertions(+), 2 deletions(-)
diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index fed80e6646..26ce50b111 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -70,6 +70,9 @@ typedef struct QCryptoBlockLUKSKeySlot
QCryptoBlockLUKSKeySlot;
#define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL
+#define QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS 2000
+#define QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS 40
+
static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
'L', 'U', 'K', 'S', 0xBA, 0xBE
};
@@ -219,6 +222,9 @@ struct QCryptoBlockLUKS {
/* Hash algorithm used in pbkdf2 function */
QCryptoHashAlgorithm hash_alg;
+
+ /* Name of the secret that was used to open the image */
+ char *secret;
};
@@ -1070,6 +1076,170 @@ qcrypto_block_luks_find_key(QCryptoBlock *block,
}
+
+/*
+ * Returns true if a slot i is marked as active
+ * (contains encrypted copy of the master key)
+ */
+static bool
+qcrypto_block_luks_slot_active(const QCryptoBlockLUKS *luks,
+ unsigned int slot_idx)
+{
+ uint32_t val = luks->header.key_slots[slot_idx].active;
+ return val == QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED;
+}
+
+/*
+ * Returns the number of slots that are marked as active
+ * (contains encrypted copy of the master key)
+ */
+static unsigned int
+qcrypto_block_luks_count_active_slots(const QCryptoBlockLUKS *luks)
+{
+ size_t i = 0;
+ unsigned int ret = 0;
+
+ for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
+ if (qcrypto_block_luks_slot_active(luks, i)) {
+ ret++;
+ }
+ }
+ return ret;
+}
+
+
+/*
+ * Finds first key slot which is not active
+ * Returns the key slot index, or -1 if doesn't exist
+ */
+static int
+qcrypto_block_luks_find_free_keyslot(const QCryptoBlockLUKS *luks)
+{
+ size_t i;
+
+ for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
+ if (!qcrypto_block_luks_slot_active(luks, i)) {
+ return i;
+ }
+ }
+ return -1;
+
+}
+
+/*
+ * Erases an keyslot given its index
+ * Returns:
+ * 0 if the keyslot was erased successfully
+ * -1 if a error occurred while erasing the keyslot
+ *
+ */
+static int
+qcrypto_block_luks_erase_key(QCryptoBlock *block,
+ unsigned int slot_idx,
+ QCryptoBlockWriteFunc writefunc,
+ void *opaque,
+ Error **errp)
+{
+ QCryptoBlockLUKS *luks = block->opaque;
+ QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx];
+ g_autofree uint8_t *garbagesplitkey = NULL;
+ size_t splitkeylen = luks->header.master_key_len * slot->stripes;
+ size_t i;
+
+ assert(slot_idx < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
+ assert(splitkeylen > 0);
+
+ garbagesplitkey = g_new0(uint8_t, splitkeylen);
+
+ /* Reset the key slot header */
+ memset(slot->salt, 0, QCRYPTO_BLOCK_LUKS_SALT_LEN);
+ slot->iterations = 0;
+ slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
+
+ qcrypto_block_luks_store_header(block, writefunc, opaque, errp);
+
+ /*
+ * Now try to erase the key material, even if the header
+ * update failed
+ */
+
+ for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS ; i++) {
+ if (qcrypto_random_bytes(garbagesplitkey, splitkeylen, errp) < 0) {
+ /*
+ * If we failed to get the random data, still write
+ * at least zeros to the key slot at least once
+ */
+
+ if (i > 0) {
+ return -1;
+ }
+ }
+
+ if (writefunc(block,
+ slot->key_offset_sector * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
+ garbagesplitkey,
+ splitkeylen,
+ opaque,
+ errp) != splitkeylen) {
+ return -1;
+ }
+ }
+ return 0;
+}
+
+
+/*
+ * Erase all the keys that match the given password
+ * Will stop when only one keyslot is remaining
+ * Returns number of slots that were erased or -1 on failure
+ */
+static int
+qcrypto_block_luks_erase_matching_keys(QCryptoBlock *block,
+ const char *password,
+ QCryptoBlockReadFunc readfunc,
+ QCryptoBlockWriteFunc writefunc,
+ void *opaque,
+ bool force,
+ Error **errp)
+{
+ QCryptoBlockLUKS *luks = block->opaque;
+ size_t i;
+ int rv;
+ g_autofree uint8_t *masterkey = NULL;
+ unsigned int erased_cnt = 0;
+ unsigned int active_slot_cnt = qcrypto_block_luks_count_active_slots(luks);
+
+ masterkey = g_new0(uint8_t, luks->header.master_key_len);
+
+ for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
+
+ /* refuse to erase last key if not forced */
+ if (!force && active_slot_cnt == 1) {
+ break;
+ }
+
+ rv = qcrypto_block_luks_load_key(block, i, password, masterkey,
+ readfunc, opaque, errp);
+ if (rv < 0) {
+ return -1;
+ }
+ if (rv == 0) {
+ continue;
+ }
+
+ rv = qcrypto_block_luks_erase_key(block, i, writefunc, opaque, errp);
+ if (rv < 0) {
+ return -1;
+ }
+
+ erased_cnt++;
+ active_slot_cnt--;
+ }
+
+ return erased_cnt;
+}
+
+
static int
qcrypto_block_luks_open(QCryptoBlock *block,
QCryptoBlockOpenOptions *options,
@@ -1100,6 +1270,7 @@ qcrypto_block_luks_open(QCryptoBlock *block,
luks = g_new0(QCryptoBlockLUKS, 1);
block->opaque = luks;
+ luks->secret = g_strdup(options->u.luks.key_secret);
ret = qcrypto_block_luks_load_header(block, readfunc, opaque, errp);
if (ret < 0) {
@@ -1215,7 +1386,7 @@ qcrypto_block_luks_create(QCryptoBlock *block,
memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
if (!luks_opts.has_iter_time) {
- luks_opts.iter_time = 2000;
+ luks_opts.iter_time = QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS;
}
if (!luks_opts.has_cipher_alg) {
luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
@@ -1273,6 +1444,8 @@ qcrypto_block_luks_create(QCryptoBlock *block,
optprefix ? optprefix : "");
goto error;
}
+ luks->secret = g_strdup(options->u.luks.key_secret);
+
password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
if (!password) {
goto error;
@@ -1504,6 +1677,182 @@ qcrypto_block_luks_create(QCryptoBlock *block,
}
+#define CHECK_NON_AMEND_OPTION(luks, luks_opts, name) \
+ if (luks_opts.has_##name && luks_opts.name != luks->name) { \
+ error_setg(errp, "Option \"" #name "\" can't be amended"); \
+ goto cleanup; \
+ }
+
+static int
+qcrypto_block_luks_amend_options(QCryptoBlock *block,
+ QCryptoBlockReadFunc readfunc,
+ QCryptoBlockWriteFunc writefunc,
+ void *opaque,
+ QCryptoBlockCreateOptions *options,
+ bool force,
+ Error **errp)
+{
+ QCryptoBlockLUKS *luks = block->opaque;
+ QCryptoBlockCreateOptionsLUKS luks_opts;
+ g_autofree char *old_password = NULL;
+ g_autofree char *password = NULL;
+ const char *unlock_secret = luks->secret;
+ g_autofree uint8_t *masterkey = NULL;
+ int slot = -1;
+ int ret = -1;
+ bool active = true;
+ int64_t iter_time = QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS;
+
+ memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
+
+ CHECK_NON_AMEND_OPTION(luks, luks_opts, cipher_alg);
+ CHECK_NON_AMEND_OPTION(luks, luks_opts, cipher_mode);
+ CHECK_NON_AMEND_OPTION(luks, luks_opts, ivgen_alg);
+ CHECK_NON_AMEND_OPTION(luks, luks_opts, ivgen_hash_alg);
+ CHECK_NON_AMEND_OPTION(luks, luks_opts, hash_alg);
+
+ /* Read given slot and check it */
+ if (luks_opts.has_slot) {
+ slot = luks_opts.slot;
+ if (slot < 0 || slot >= QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS) {
+ error_setg(errp,
+ "Given key slot %i is not supported by LUKS", slot);
+ goto cleanup;
+ }
+ }
+
+ if (luks_opts.has_iter_time) {
+ iter_time = luks_opts.iter_time;
+ }
+
+ if (luks_opts.has_active && luks_opts.active == false) {
+ active = false;
+ }
+
+ if (active) {
+ /* Check that we are not overwriting an active slot */
+ if (!force && slot != -1 &&
+ qcrypto_block_luks_slot_active(luks, slot)) {
+
+ error_setg(errp, "Can't update an active key slot %i",
+ slot);
+ goto cleanup;
+ }
+
+ /* check that we have the passwords*/
+ if (!luks_opts.has_key_secret) {
+ error_setg(errp, "Can't add a key slot without a password");
+ goto cleanup;
+ }
+
+ if (luks_opts.has_unlock_secret) {
+ unlock_secret = luks_opts.unlock_secret;
+ }
+
+ /* Read the old password */
+ old_password = qcrypto_secret_lookup_as_utf8(unlock_secret, errp);
+ if (!old_password) {
+ goto cleanup;
+ }
+
+ masterkey = g_new0(uint8_t, luks->header.master_key_len);
+
+ /* Retrieve the master key*/
+ if (qcrypto_block_luks_find_key(block, old_password, masterkey,
+ readfunc, opaque,
+ errp) < 0) {
+ error_append_hint(errp,
+ "'unlock-secret' failed to unlock the image");
+ goto cleanup;
+ }
+
+ /* Read the new password*/
+ password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
+ if (!password) {
+ goto cleanup;
+ }
+
+ /* Find the new slot to write to */
+ if (slot == -1) {
+ slot = qcrypto_block_luks_find_free_keyslot(luks);
+
+ if (slot == -1) {
+ error_setg(errp,
+ "Can't add a keyslot - all key slots are in use");
+ goto cleanup;
+ }
+ }
+
+ /* Store the master key to the new slot */
+ if (qcrypto_block_luks_store_key(block, slot, password, masterkey,
+ iter_time, writefunc, opaque,
+ errp)) {
+ error_append_hint(errp, "Failed to store the keyslot %i", slot);
+ goto cleanup;
+ }
+
+ } else {
+ /* Check that we are not erasing last key slot */
+ if (qcrypto_block_luks_count_active_slots(luks) <= 1) {
+ if (!force) {
+ error_setg(errp, "Only one slot active - can't erase");
+ goto cleanup;
+ }
+ }
+
+ if (slot != -1) {
+ /* Check that we are not erasing an inactive slot */
+ if (!qcrypto_block_luks_slot_active(luks, luks_opts.slot)) {
+ if (!force) {
+ error_setg(errp, "Can't erase an inactive key slot %i",
+ slot);
+ goto cleanup;
+ }
+ }
+
+ /* Erase the given slot */
+ if (qcrypto_block_luks_erase_key(block, slot,
+ writefunc, opaque, errp)) {
+ goto cleanup;
+ }
+
+ } else {
+ if (!luks_opts.has_key_secret) {
+ error_setg(errp,
+ "To erase a keyslot you have to specify either the"
+ "slot index or a password "
+ "(to erase all slots that match it)");
+ goto cleanup;
+ }
+
+ password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret,
+ errp);
+ if (!password) {
+ goto cleanup;
+ }
+
+ ret = qcrypto_block_luks_erase_matching_keys(block, password,
+ readfunc, writefunc,
+ opaque, force, errp);
+ if (ret == 0) {
+ error_setg(errp,
+ "Didn't erase a keyslot, because no keyslots match"
+ " the given password");
+ ret = -EINVAL;
+ goto cleanup;
+ }
+
+ if (ret < 0) {
+ goto cleanup;
+ }
+ }
+ }
+ ret = 0;
+cleanup:
+ return ret;
+}
+
+
static int qcrypto_block_luks_get_info(QCryptoBlock *block,
QCryptoBlockInfo *info,
Error **errp)
@@ -1551,7 +1900,9 @@ static int qcrypto_block_luks_get_info(QCryptoBlock
*block,
static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
{
- g_free(block->opaque);
+ QCryptoBlockLUKS *luks = block->opaque;
+ g_free(luks->secret);
+ g_free(luks);
}
@@ -1588,6 +1939,7 @@ qcrypto_block_luks_encrypt(QCryptoBlock *block,
const QCryptoBlockDriver qcrypto_block_driver_luks = {
.open = qcrypto_block_luks_open,
.create = qcrypto_block_luks_create,
+ .amend = qcrypto_block_luks_amend_options,
.get_info = qcrypto_block_luks_get_info,
.cleanup = qcrypto_block_luks_cleanup,
.decrypt = qcrypto_block_luks_decrypt,
--
2.17.2
