'zfs receive' fails with "dataset is busy"

[mirror_zfs.git] / module / zfs / dsl_crypt.c

/*
 * CDDL HEADER START
 *
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2017, Datto, Inc. All rights reserved.
 */

#include <sys/dsl_crypt.h>
#include <sys/dsl_pool.h>
#include <sys/zap.h>
#include <sys/zil.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_prop.h>
#include <sys/spa_impl.h>
#include <sys/dmu_objset.h>
#include <sys/zvol.h>

/*
 * This file's primary purpose is for managing master encryption keys in
 * memory and on disk. For more info on how these keys are used, see the
 * block comment in zio_crypt.c.
 *
 * All master keys are stored encrypted on disk in the form of the DSL
 * Crypto Key ZAP object. The binary key data in this object is always
 * randomly generated and is encrypted with the user's wrapping key. This
 * layer of indirection allows the user to change their key without
 * needing to re-encrypt the entire dataset. The ZAP also holds on to the
 * (non-encrypted) encryption algorithm identifier, IV, and MAC needed to
 * safely decrypt the master key. For more info on the user's key see the
 * block comment in libzfs_crypto.c
 *
 * In-memory encryption keys are managed through the spa_keystore. The
 * keystore consists of 3 AVL trees, which are as follows:
 *
 * The Wrapping Key Tree:
 * The wrapping key (wkey) tree stores the user's keys that are fed into the
 * kernel through 'zfs load-key' and related commands. Datasets inherit their
 * parent's wkey by default, so these structures are refcounted. The wrapping
 * keys remain in memory until they are explicitly unloaded (with
 * "zfs unload-key"). Unloading is only possible when no datasets are using
 * them (refcount=0).
 *
 * The DSL Crypto Key Tree:
 * The DSL Crypto Keys (DCK) are the in-memory representation of decrypted
 * master keys. They are used by the functions in zio_crypt.c to perform
 * encryption, decryption, and authentication. Snapshots and clones of a given
 * dataset will share a DSL Crypto Key, so they are also refcounted. Once the
 * refcount on a key hits zero, it is immediately zeroed out and freed.
 *
 * The Crypto Key Mapping Tree:
 * The zio layer needs to lookup master keys by their dataset object id. Since
 * the DSL Crypto Keys can belong to multiple datasets, we maintain a tree of
 * dsl_key_mapping_t's which essentially just map the dataset object id to its
 * appropriate DSL Crypto Key. The management for creating and destroying these
 * mappings hooks into the code for owning and disowning datasets. Usually,
 * there will only be one active dataset owner, but there are times
 * (particularly during dataset creation and destruction) when this may not be
 * true or the dataset may not be initialized enough to own. As a result, this
 * object is also refcounted.
 */

static void
dsl_wrapping_key_hold(dsl_wrapping_key_t *wkey, void *tag)
{
        (void) refcount_add(&wkey->wk_refcnt, tag);
}

static void
dsl_wrapping_key_rele(dsl_wrapping_key_t *wkey, void *tag)
{
        (void) refcount_remove(&wkey->wk_refcnt, tag);
}

static void
dsl_wrapping_key_free(dsl_wrapping_key_t *wkey)
{
        ASSERT0(refcount_count(&wkey->wk_refcnt));

        if (wkey->wk_key.ck_data) {
                bzero(wkey->wk_key.ck_data,
                    CRYPTO_BITS2BYTES(wkey->wk_key.ck_length));
                kmem_free(wkey->wk_key.ck_data,
                    CRYPTO_BITS2BYTES(wkey->wk_key.ck_length));
        }

        refcount_destroy(&wkey->wk_refcnt);
        kmem_free(wkey, sizeof (dsl_wrapping_key_t));
}

static int
dsl_wrapping_key_create(uint8_t *wkeydata, zfs_keyformat_t keyformat,
    uint64_t salt, uint64_t iters, dsl_wrapping_key_t **wkey_out)
{
        int ret;
        dsl_wrapping_key_t *wkey;

        /* allocate the wrapping key */
        wkey = kmem_alloc(sizeof (dsl_wrapping_key_t), KM_SLEEP);
        if (!wkey)
                return (SET_ERROR(ENOMEM));

        /* allocate and initialize the underlying crypto key */
        wkey->wk_key.ck_data = kmem_alloc(WRAPPING_KEY_LEN, KM_SLEEP);
        if (!wkey->wk_key.ck_data) {
                ret = ENOMEM;
                goto error;
        }

        wkey->wk_key.ck_format = CRYPTO_KEY_RAW;
        wkey->wk_key.ck_length = CRYPTO_BYTES2BITS(WRAPPING_KEY_LEN);
        bcopy(wkeydata, wkey->wk_key.ck_data, WRAPPING_KEY_LEN);

        /* initialize the rest of the struct */
        refcount_create(&wkey->wk_refcnt);
        wkey->wk_keyformat = keyformat;
        wkey->wk_salt = salt;
        wkey->wk_iters = iters;

        *wkey_out = wkey;
        return (0);

error:
        dsl_wrapping_key_free(wkey);

        *wkey_out = NULL;
        return (ret);
}

int
dsl_crypto_params_create_nvlist(dcp_cmd_t cmd, nvlist_t *props,
    nvlist_t *crypto_args, dsl_crypto_params_t **dcp_out)
{
        int ret;
        uint64_t crypt = ZIO_CRYPT_INHERIT;
        uint64_t keyformat = ZFS_KEYFORMAT_NONE;
        uint64_t salt = 0, iters = 0;
        dsl_crypto_params_t *dcp = NULL;
        dsl_wrapping_key_t *wkey = NULL;
        uint8_t *wkeydata = NULL;
        uint_t wkeydata_len = 0;
        char *keylocation = NULL;

        dcp = kmem_zalloc(sizeof (dsl_crypto_params_t), KM_SLEEP);
        if (!dcp) {
                ret = SET_ERROR(ENOMEM);
                goto error;
        }

        dcp->cp_cmd = cmd;

        /* get relevant arguments from the nvlists */
        if (props != NULL) {
                (void) nvlist_lookup_uint64(props,
                    zfs_prop_to_name(ZFS_PROP_ENCRYPTION), &crypt);
                (void) nvlist_lookup_uint64(props,
                    zfs_prop_to_name(ZFS_PROP_KEYFORMAT), &keyformat);
                (void) nvlist_lookup_string(props,
                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION), &keylocation);
                (void) nvlist_lookup_uint64(props,
                    zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT), &salt);
                (void) nvlist_lookup_uint64(props,
                    zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS), &iters);

                dcp->cp_crypt = crypt;
        }

        if (crypto_args != NULL) {
                (void) nvlist_lookup_uint8_array(crypto_args, "wkeydata",
                    &wkeydata, &wkeydata_len);
        }

        /* check for valid command */
        if (dcp->cp_cmd >= DCP_CMD_MAX) {
                ret = SET_ERROR(EINVAL);
                goto error;
        } else {
                dcp->cp_cmd = cmd;
        }

        /* check for valid crypt */
        if (dcp->cp_crypt >= ZIO_CRYPT_FUNCTIONS) {
                ret = SET_ERROR(EINVAL);
                goto error;
        } else {
                dcp->cp_crypt = crypt;
        }

        /* check for valid keyformat */
        if (keyformat >= ZFS_KEYFORMAT_FORMATS) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* check for a valid keylocation (of any kind) and copy it in */
        if (keylocation != NULL) {
                if (!zfs_prop_valid_keylocation(keylocation, B_FALSE)) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                dcp->cp_keylocation = spa_strdup(keylocation);
        }

        /* check wrapping key length, if given */
        if (wkeydata != NULL && wkeydata_len != WRAPPING_KEY_LEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* if the user asked for the deault crypt, determine that now */
        if (dcp->cp_crypt == ZIO_CRYPT_ON)
                dcp->cp_crypt = ZIO_CRYPT_ON_VALUE;

        /* create the wrapping key from the raw data */
        if (wkeydata != NULL) {
                /* create the wrapping key with the verified parameters */
                ret = dsl_wrapping_key_create(wkeydata, keyformat, salt,
                    iters, &wkey);
                if (ret != 0)
                        goto error;

                dcp->cp_wkey = wkey;
        }

        /*
         * Remove the encryption properties from the nvlist since they are not
         * maintained through the DSL.
         */
        (void) nvlist_remove_all(props, zfs_prop_to_name(ZFS_PROP_ENCRYPTION));
        (void) nvlist_remove_all(props, zfs_prop_to_name(ZFS_PROP_KEYFORMAT));
        (void) nvlist_remove_all(props, zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT));
        (void) nvlist_remove_all(props,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS));

        *dcp_out = dcp;

        return (0);

error:
        if (wkey != NULL)
                dsl_wrapping_key_free(wkey);
        if (dcp != NULL)
                kmem_free(dcp, sizeof (dsl_crypto_params_t));

        *dcp_out = NULL;
        return (ret);
}

void
dsl_crypto_params_free(dsl_crypto_params_t *dcp, boolean_t unload)
{
        if (dcp == NULL)
                return;

        if (dcp->cp_keylocation != NULL)
                spa_strfree(dcp->cp_keylocation);
        if (unload && dcp->cp_wkey != NULL)
                dsl_wrapping_key_free(dcp->cp_wkey);

        kmem_free(dcp, sizeof (dsl_crypto_params_t));
}

static int
spa_crypto_key_compare(const void *a, const void *b)
{
        const dsl_crypto_key_t *dcka = a;
        const dsl_crypto_key_t *dckb = b;

        if (dcka->dck_obj < dckb->dck_obj)
                return (-1);
        if (dcka->dck_obj > dckb->dck_obj)
                return (1);
        return (0);
}

static int
spa_key_mapping_compare(const void *a, const void *b)
{
        const dsl_key_mapping_t *kma = a;
        const dsl_key_mapping_t *kmb = b;

        if (kma->km_dsobj < kmb->km_dsobj)
                return (-1);
        if (kma->km_dsobj > kmb->km_dsobj)
                return (1);
        return (0);
}

static int
spa_wkey_compare(const void *a, const void *b)
{
        const dsl_wrapping_key_t *wka = a;
        const dsl_wrapping_key_t *wkb = b;

        if (wka->wk_ddobj < wkb->wk_ddobj)
                return (-1);
        if (wka->wk_ddobj > wkb->wk_ddobj)
                return (1);
        return (0);
}

void
spa_keystore_init(spa_keystore_t *sk)
{
        rw_init(&sk->sk_dk_lock, NULL, RW_DEFAULT, NULL);
        rw_init(&sk->sk_km_lock, NULL, RW_DEFAULT, NULL);
        rw_init(&sk->sk_wkeys_lock, NULL, RW_DEFAULT, NULL);
        avl_create(&sk->sk_dsl_keys, spa_crypto_key_compare,
            sizeof (dsl_crypto_key_t),
            offsetof(dsl_crypto_key_t, dck_avl_link));
        avl_create(&sk->sk_key_mappings, spa_key_mapping_compare,
            sizeof (dsl_key_mapping_t),
            offsetof(dsl_key_mapping_t, km_avl_link));
        avl_create(&sk->sk_wkeys, spa_wkey_compare, sizeof (dsl_wrapping_key_t),
            offsetof(dsl_wrapping_key_t, wk_avl_link));
}

void
spa_keystore_fini(spa_keystore_t *sk)
{
        dsl_wrapping_key_t *wkey;
        void *cookie = NULL;

        ASSERT(avl_is_empty(&sk->sk_dsl_keys));
        ASSERT(avl_is_empty(&sk->sk_key_mappings));

        while ((wkey = avl_destroy_nodes(&sk->sk_wkeys, &cookie)) != NULL)
                dsl_wrapping_key_free(wkey);

        avl_destroy(&sk->sk_wkeys);
        avl_destroy(&sk->sk_key_mappings);
        avl_destroy(&sk->sk_dsl_keys);
        rw_destroy(&sk->sk_wkeys_lock);
        rw_destroy(&sk->sk_km_lock);
        rw_destroy(&sk->sk_dk_lock);
}

static int
dsl_dir_get_encryption_root_ddobj(dsl_dir_t *dd, uint64_t *rddobj)
{
        if (dd->dd_crypto_obj == 0)
                return (SET_ERROR(ENOENT));

        return (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            DSL_CRYPTO_KEY_ROOT_DDOBJ, 8, 1, rddobj));
}

int
dsl_dir_get_encryption_version(dsl_dir_t *dd, uint64_t *version)
{
        *version = 0;

        if (dd->dd_crypto_obj == 0)
                return (SET_ERROR(ENOENT));

        /* version 0 is implied by ENOENT */
        (void) zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            DSL_CRYPTO_KEY_VERSION, 8, 1, version);

        return (0);
}

boolean_t
dsl_dir_incompatible_encryption_version(dsl_dir_t *dd)
{
        int ret;
        uint64_t version = 0;

        ret = dsl_dir_get_encryption_version(dd, &version);
        if (ret != 0)
                return (B_FALSE);

        return (version != ZIO_CRYPT_KEY_CURRENT_VERSION);
}

static int
spa_keystore_wkey_hold_ddobj_impl(spa_t *spa, uint64_t ddobj,
    void *tag, dsl_wrapping_key_t **wkey_out)
{
        int ret;
        dsl_wrapping_key_t search_wkey;
        dsl_wrapping_key_t *found_wkey;

        ASSERT(RW_LOCK_HELD(&spa->spa_keystore.sk_wkeys_lock));

        /* init the search wrapping key */
        search_wkey.wk_ddobj = ddobj;

        /* lookup the wrapping key */
        found_wkey = avl_find(&spa->spa_keystore.sk_wkeys, &search_wkey, NULL);
        if (!found_wkey) {
                ret = SET_ERROR(ENOENT);
                goto error;
        }

        /* increment the refcount */
        dsl_wrapping_key_hold(found_wkey, tag);

        *wkey_out = found_wkey;
        return (0);

error:
        *wkey_out = NULL;
        return (ret);
}

static int
spa_keystore_wkey_hold_dd(spa_t *spa, dsl_dir_t *dd, void *tag,
    dsl_wrapping_key_t **wkey_out)
{
        int ret;
        dsl_wrapping_key_t *wkey;
        uint64_t rddobj;
        boolean_t locked = B_FALSE;

        if (!RW_WRITE_HELD(&spa->spa_keystore.sk_wkeys_lock)) {
                rw_enter(&spa->spa_keystore.sk_wkeys_lock, RW_READER);
                locked = B_TRUE;
        }

        /* get the ddobj that the keylocation property was inherited from */
        ret = dsl_dir_get_encryption_root_ddobj(dd, &rddobj);
        if (ret != 0)
                goto error;

        /* lookup the wkey in the avl tree */
        ret = spa_keystore_wkey_hold_ddobj_impl(spa, rddobj, tag, &wkey);
        if (ret != 0)
                goto error;

        /* unlock the wkey tree if we locked it */
        if (locked)
                rw_exit(&spa->spa_keystore.sk_wkeys_lock);

        *wkey_out = wkey;
        return (0);

error:
        if (locked)
                rw_exit(&spa->spa_keystore.sk_wkeys_lock);

        *wkey_out = NULL;
        return (ret);
}

int
dsl_crypto_can_set_keylocation(const char *dsname, const char *keylocation)
{
        int ret = 0;
        dsl_dir_t *dd = NULL;
        dsl_pool_t *dp = NULL;
        uint64_t rddobj;

        /* hold the dsl dir */
        ret = dsl_pool_hold(dsname, FTAG, &dp);
        if (ret != 0)
                goto out;

        ret = dsl_dir_hold(dp, dsname, FTAG, &dd, NULL);
        if (ret != 0)
                goto out;

        /* if dd is not encrypted, the value may only be "none" */
        if (dd->dd_crypto_obj == 0) {
                if (strcmp(keylocation, "none") != 0) {
                        ret = SET_ERROR(EACCES);
                        goto out;
                }

                ret = 0;
                goto out;
        }

        /* check for a valid keylocation for encrypted datasets */
        if (!zfs_prop_valid_keylocation(keylocation, B_TRUE)) {
                ret = SET_ERROR(EINVAL);
                goto out;
        }

        /* check that this is an encryption root */
        ret = dsl_dir_get_encryption_root_ddobj(dd, &rddobj);
        if (ret != 0)
                goto out;

        if (rddobj != dd->dd_object) {
                ret = SET_ERROR(EACCES);
                goto out;
        }

        dsl_dir_rele(dd, FTAG);
        dsl_pool_rele(dp, FTAG);

        return (0);

out:
        if (dd != NULL)
                dsl_dir_rele(dd, FTAG);
        if (dp != NULL)
                dsl_pool_rele(dp, FTAG);

        return (ret);
}

static void
dsl_crypto_key_free(dsl_crypto_key_t *dck)
{
        ASSERT(refcount_count(&dck->dck_holds) == 0);

        /* destroy the zio_crypt_key_t */
        zio_crypt_key_destroy(&dck->dck_key);

        /* free the refcount, wrapping key, and lock */
        refcount_destroy(&dck->dck_holds);
        if (dck->dck_wkey)
                dsl_wrapping_key_rele(dck->dck_wkey, dck);

        /* free the key */
        kmem_free(dck, sizeof (dsl_crypto_key_t));
}

static void
dsl_crypto_key_rele(dsl_crypto_key_t *dck, void *tag)
{
        if (refcount_remove(&dck->dck_holds, tag) == 0)
                dsl_crypto_key_free(dck);
}

static int
dsl_crypto_key_open(objset_t *mos, dsl_wrapping_key_t *wkey,
    uint64_t dckobj, void *tag, dsl_crypto_key_t **dck_out)
{
        int ret;
        uint64_t crypt = 0, guid = 0, version = 0;
        uint8_t raw_keydata[MASTER_KEY_MAX_LEN];
        uint8_t raw_hmac_keydata[SHA512_HMAC_KEYLEN];
        uint8_t iv[WRAPPING_IV_LEN];
        uint8_t mac[WRAPPING_MAC_LEN];
        dsl_crypto_key_t *dck;

        /* allocate and initialize the key */
        dck = kmem_zalloc(sizeof (dsl_crypto_key_t), KM_SLEEP);
        if (!dck)
                return (SET_ERROR(ENOMEM));

        /* fetch all of the values we need from the ZAP */
        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_CRYPTO_SUITE, 8, 1,
            &crypt);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_GUID, 8, 1, &guid);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_MASTER_KEY, 1,
            MASTER_KEY_MAX_LEN, raw_keydata);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_HMAC_KEY, 1,
            SHA512_HMAC_KEYLEN, raw_hmac_keydata);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_IV, 1, WRAPPING_IV_LEN,
            iv);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_MAC, 1, WRAPPING_MAC_LEN,
            mac);
        if (ret != 0)
                goto error;

        /* the initial on-disk format for encryption did not have a version */
        (void) zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_VERSION, 8, 1, &version);

        /*
         * Unwrap the keys. If there is an error return EACCES to indicate
         * an authentication failure.
         */
        ret = zio_crypt_key_unwrap(&wkey->wk_key, crypt, version, guid,
            raw_keydata, raw_hmac_keydata, iv, mac, &dck->dck_key);
        if (ret != 0) {
                ret = SET_ERROR(EACCES);
                goto error;
        }

        /* finish initializing the dsl_crypto_key_t */
        refcount_create(&dck->dck_holds);
        dsl_wrapping_key_hold(wkey, dck);
        dck->dck_wkey = wkey;
        dck->dck_obj = dckobj;
        refcount_add(&dck->dck_holds, tag);

        *dck_out = dck;
        return (0);

error:
        if (dck != NULL) {
                bzero(dck, sizeof (dsl_crypto_key_t));
                kmem_free(dck, sizeof (dsl_crypto_key_t));
        }

        *dck_out = NULL;
        return (ret);
}

static int
spa_keystore_dsl_key_hold_impl(spa_t *spa, uint64_t dckobj, void *tag,
    dsl_crypto_key_t **dck_out)
{
        int ret;
        dsl_crypto_key_t search_dck;
        dsl_crypto_key_t *found_dck;

        ASSERT(RW_LOCK_HELD(&spa->spa_keystore.sk_dk_lock));

        /* init the search key */
        search_dck.dck_obj = dckobj;

        /* find the matching key in the keystore */
        found_dck = avl_find(&spa->spa_keystore.sk_dsl_keys, &search_dck, NULL);
        if (!found_dck) {
                ret = SET_ERROR(ENOENT);
                goto error;
        }

        /* increment the refcount */
        refcount_add(&found_dck->dck_holds, tag);

        *dck_out = found_dck;
        return (0);

error:
        *dck_out = NULL;
        return (ret);
}

static int
spa_keystore_dsl_key_hold_dd(spa_t *spa, dsl_dir_t *dd, void *tag,
    dsl_crypto_key_t **dck_out)
{
        int ret;
        avl_index_t where;
        dsl_crypto_key_t *dck_io = NULL, *dck_ks = NULL;
        dsl_wrapping_key_t *wkey = NULL;
        uint64_t dckobj = dd->dd_crypto_obj;

        /* Lookup the key in the tree of currently loaded keys */
        rw_enter(&spa->spa_keystore.sk_dk_lock, RW_READER);
        ret = spa_keystore_dsl_key_hold_impl(spa, dckobj, tag, &dck_ks);
        rw_exit(&spa->spa_keystore.sk_dk_lock);
        if (ret == 0) {
                *dck_out = dck_ks;
                return (0);
        }

        /* Lookup the wrapping key from the keystore */
        ret = spa_keystore_wkey_hold_dd(spa, dd, FTAG, &wkey);
        if (ret != 0) {
                *dck_out = NULL;
                return (SET_ERROR(EACCES));
        }

        /* Read the key from disk */
        ret = dsl_crypto_key_open(spa->spa_meta_objset, wkey, dckobj,
            tag, &dck_io);
        if (ret != 0) {
                dsl_wrapping_key_rele(wkey, FTAG);
                *dck_out = NULL;
                return (ret);
        }

        /*
         * Add the key to the keystore.  It may already exist if it was
         * added while performing the read from disk.  In this case discard
         * it and return the key from the keystore.
         */
        rw_enter(&spa->spa_keystore.sk_dk_lock, RW_WRITER);
        ret = spa_keystore_dsl_key_hold_impl(spa, dckobj, tag, &dck_ks);
        if (ret != 0) {
                avl_find(&spa->spa_keystore.sk_dsl_keys, dck_io, &where);
                avl_insert(&spa->spa_keystore.sk_dsl_keys, dck_io, where);
                *dck_out = dck_io;
        } else {
                dsl_crypto_key_free(dck_io);
                *dck_out = dck_ks;
        }

        /* Release the wrapping key (the dsl key now has a reference to it) */
        dsl_wrapping_key_rele(wkey, FTAG);
        rw_exit(&spa->spa_keystore.sk_dk_lock);

        return (0);
}

void
spa_keystore_dsl_key_rele(spa_t *spa, dsl_crypto_key_t *dck, void *tag)
{
        rw_enter(&spa->spa_keystore.sk_dk_lock, RW_WRITER);

        if (refcount_remove(&dck->dck_holds, tag) == 0) {
                avl_remove(&spa->spa_keystore.sk_dsl_keys, dck);
                dsl_crypto_key_free(dck);
        }

        rw_exit(&spa->spa_keystore.sk_dk_lock);
}

int
spa_keystore_load_wkey_impl(spa_t *spa, dsl_wrapping_key_t *wkey)
{
        int ret;
        avl_index_t where;
        dsl_wrapping_key_t *found_wkey;

        rw_enter(&spa->spa_keystore.sk_wkeys_lock, RW_WRITER);

        /* insert the wrapping key into the keystore */
        found_wkey = avl_find(&spa->spa_keystore.sk_wkeys, wkey, &where);
        if (found_wkey != NULL) {
                ret = SET_ERROR(EEXIST);
                goto error_unlock;
        }
        avl_insert(&spa->spa_keystore.sk_wkeys, wkey, where);

        rw_exit(&spa->spa_keystore.sk_wkeys_lock);

        return (0);

error_unlock:
        rw_exit(&spa->spa_keystore.sk_wkeys_lock);
        return (ret);
}

int
spa_keystore_load_wkey(const char *dsname, dsl_crypto_params_t *dcp,
    boolean_t noop)
{
        int ret;
        dsl_dir_t *dd = NULL;
        dsl_crypto_key_t *dck = NULL;
        dsl_wrapping_key_t *wkey = dcp->cp_wkey;
        dsl_pool_t *dp = NULL;
        uint64_t keyformat, salt, iters;

        /*
         * We don't validate the wrapping key's keyformat, salt, or iters
         * since they will never be needed after the DCK has been wrapped.
         */
        if (dcp->cp_wkey == NULL ||
            dcp->cp_cmd != DCP_CMD_NONE ||
            dcp->cp_crypt != ZIO_CRYPT_INHERIT ||
            dcp->cp_keylocation != NULL)
                return (SET_ERROR(EINVAL));

        ret = dsl_pool_hold(dsname, FTAG, &dp);
        if (ret != 0)
                goto error;

        if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ENCRYPTION)) {
                ret = (SET_ERROR(ENOTSUP));
                goto error;
        }

        /* hold the dsl dir */
        ret = dsl_dir_hold(dp, dsname, FTAG, &dd, NULL);
        if (ret != 0)
                goto error;

        /* initialize the wkey's ddobj */
        wkey->wk_ddobj = dd->dd_object;

        /* verify that the wkey is correct by opening its dsl key */
        ret = dsl_crypto_key_open(dp->dp_meta_objset, wkey,
            dd->dd_crypto_obj, FTAG, &dck);
        if (ret != 0)
                goto error;

        /* initialize the wkey encryption parameters from the DSL Crypto Key */
        ret = zap_lookup(dp->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_KEYFORMAT), 8, 1, &keyformat);
        if (ret != 0)
                goto error;

        ret = zap_lookup(dp->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT), 8, 1, &salt);
        if (ret != 0)
                goto error;

        ret = zap_lookup(dp->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS), 8, 1, &iters);
        if (ret != 0)
                goto error;

        ASSERT3U(keyformat, <, ZFS_KEYFORMAT_FORMATS);
        ASSERT3U(keyformat, !=, ZFS_KEYFORMAT_NONE);
        IMPLY(keyformat == ZFS_KEYFORMAT_PASSPHRASE, iters != 0);
        IMPLY(keyformat == ZFS_KEYFORMAT_PASSPHRASE, salt != 0);
        IMPLY(keyformat != ZFS_KEYFORMAT_PASSPHRASE, iters == 0);
        IMPLY(keyformat != ZFS_KEYFORMAT_PASSPHRASE, salt == 0);

        wkey->wk_keyformat = keyformat;
        wkey->wk_salt = salt;
        wkey->wk_iters = iters;

        /*
         * At this point we have verified the wkey and confirmed that it can
         * be used to decrypt a DSL Crypto Key. We can simply cleanup and
         * return if this is all the user wanted to do.
         */
        if (noop)
                goto error;

        /* insert the wrapping key into the keystore */
        ret = spa_keystore_load_wkey_impl(dp->dp_spa, wkey);
        if (ret != 0)
                goto error;

        dsl_crypto_key_rele(dck, FTAG);
        dsl_dir_rele(dd, FTAG);
        dsl_pool_rele(dp, FTAG);

        /* create any zvols under this ds */
        zvol_create_minors(dp->dp_spa, dsname, B_TRUE);

        return (0);

error:
        if (dck != NULL)
                dsl_crypto_key_rele(dck, FTAG);
        if (dd != NULL)
                dsl_dir_rele(dd, FTAG);
        if (dp != NULL)
                dsl_pool_rele(dp, FTAG);

        return (ret);
}

int
spa_keystore_unload_wkey_impl(spa_t *spa, uint64_t ddobj)
{
        int ret;
        dsl_wrapping_key_t search_wkey;
        dsl_wrapping_key_t *found_wkey;

        /* init the search wrapping key */
        search_wkey.wk_ddobj = ddobj;

        rw_enter(&spa->spa_keystore.sk_wkeys_lock, RW_WRITER);

        /* remove the wrapping key from the keystore */
        found_wkey = avl_find(&spa->spa_keystore.sk_wkeys,
            &search_wkey, NULL);
        if (!found_wkey) {
                ret = SET_ERROR(ENOENT);
                goto error_unlock;
        } else if (refcount_count(&found_wkey->wk_refcnt) != 0) {
                ret = SET_ERROR(EBUSY);
                goto error_unlock;
        }
        avl_remove(&spa->spa_keystore.sk_wkeys, found_wkey);

        rw_exit(&spa->spa_keystore.sk_wkeys_lock);

        /* free the wrapping key */
        dsl_wrapping_key_free(found_wkey);

        return (0);

error_unlock:
        rw_exit(&spa->spa_keystore.sk_wkeys_lock);
        return (ret);
}

int
spa_keystore_unload_wkey(const char *dsname)
{
        int ret = 0;
        dsl_dir_t *dd = NULL;
        dsl_pool_t *dp = NULL;

        /* hold the dsl dir */
        ret = dsl_pool_hold(dsname, FTAG, &dp);
        if (ret != 0)
                goto error;

        if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ENCRYPTION)) {
                ret = (SET_ERROR(ENOTSUP));
                goto error;
        }

        ret = dsl_dir_hold(dp, dsname, FTAG, &dd, NULL);
        if (ret != 0)
                goto error;

        /* unload the wkey */
        ret = spa_keystore_unload_wkey_impl(dp->dp_spa, dd->dd_object);
        if (ret != 0)
                goto error;

        dsl_dir_rele(dd, FTAG);
        dsl_pool_rele(dp, FTAG);

        /* remove any zvols under this ds */
        zvol_remove_minors(dp->dp_spa, dsname, B_TRUE);

        return (0);

error:
        if (dd != NULL)
                dsl_dir_rele(dd, FTAG);
        if (dp != NULL)
                dsl_pool_rele(dp, FTAG);

        return (ret);
}

int
spa_keystore_create_mapping_impl(spa_t *spa, uint64_t dsobj,
    dsl_dir_t *dd, void *tag)
{
        int ret;
        avl_index_t where;
        dsl_key_mapping_t *km, *found_km;
        boolean_t should_free = B_FALSE;

        /* Allocate and initialize the mapping */
        km = kmem_zalloc(sizeof (dsl_key_mapping_t), KM_SLEEP);
        refcount_create(&km->km_refcnt);

        ret = spa_keystore_dsl_key_hold_dd(spa, dd, km, &km->km_key);
        if (ret != 0) {
                refcount_destroy(&km->km_refcnt);
                kmem_free(km, sizeof (dsl_key_mapping_t));
                return (ret);
        }

        km->km_dsobj = dsobj;

        rw_enter(&spa->spa_keystore.sk_km_lock, RW_WRITER);

        /*
         * If a mapping already exists, simply increment its refcount and
         * cleanup the one we made. We want to allocate / free outside of
         * the lock because this lock is also used by the zio layer to lookup
         * key mappings. Otherwise, use the one we created. Normally, there will
         * only be one active reference at a time (the objset owner), but there
         * are times when there could be multiple async users.
         */
        found_km = avl_find(&spa->spa_keystore.sk_key_mappings, km, &where);
        if (found_km != NULL) {
                should_free = B_TRUE;
                refcount_add(&found_km->km_refcnt, tag);
        } else {
                refcount_add(&km->km_refcnt, tag);
                avl_insert(&spa->spa_keystore.sk_key_mappings, km, where);
        }

        rw_exit(&spa->spa_keystore.sk_km_lock);

        if (should_free) {
                spa_keystore_dsl_key_rele(spa, km->km_key, km);
                refcount_destroy(&km->km_refcnt);
                kmem_free(km, sizeof (dsl_key_mapping_t));
        }

        return (0);
}

int
spa_keystore_create_mapping(spa_t *spa, dsl_dataset_t *ds, void *tag)
{
        return (spa_keystore_create_mapping_impl(spa, ds->ds_object,
            ds->ds_dir, tag));
}

int
spa_keystore_remove_mapping(spa_t *spa, uint64_t dsobj, void *tag)
{
        int ret;
        dsl_key_mapping_t search_km;
        dsl_key_mapping_t *found_km;
        boolean_t should_free = B_FALSE;

        /* init the search key mapping */
        search_km.km_dsobj = dsobj;

        rw_enter(&spa->spa_keystore.sk_km_lock, RW_WRITER);

        /* find the matching mapping */
        found_km = avl_find(&spa->spa_keystore.sk_key_mappings,
            &search_km, NULL);
        if (found_km == NULL) {
                ret = SET_ERROR(ENOENT);
                goto error_unlock;
        }

        /*
         * Decrement the refcount on the mapping and remove it from the tree if
         * it is zero. Try to minimize time spent in this lock by deferring
         * cleanup work.
         */
        if (refcount_remove(&found_km->km_refcnt, tag) == 0) {
                should_free = B_TRUE;
                avl_remove(&spa->spa_keystore.sk_key_mappings, found_km);
        }

        rw_exit(&spa->spa_keystore.sk_km_lock);

        /* destroy the key mapping */
        if (should_free) {
                spa_keystore_dsl_key_rele(spa, found_km->km_key, found_km);
                kmem_free(found_km, sizeof (dsl_key_mapping_t));
        }

        return (0);

error_unlock:
        rw_exit(&spa->spa_keystore.sk_km_lock);
        return (ret);
}

/*
 * This function is primarily used by the zio and arc layer to lookup
 * DSL Crypto Keys for encryption. Callers must release the key with
 * spa_keystore_dsl_key_rele(). The function may also be called with
 * dck_out == NULL and tag == NULL to simply check that a key exists
 * without getting a reference to it.
 */
int
spa_keystore_lookup_key(spa_t *spa, uint64_t dsobj, void *tag,
    dsl_crypto_key_t **dck_out)
{
        int ret;
        dsl_key_mapping_t search_km;
        dsl_key_mapping_t *found_km;

        ASSERT((tag != NULL && dck_out != NULL) ||
            (tag == NULL && dck_out == NULL));

        /* init the search key mapping */
        search_km.km_dsobj = dsobj;

        rw_enter(&spa->spa_keystore.sk_km_lock, RW_READER);

        /* remove the mapping from the tree */
        found_km = avl_find(&spa->spa_keystore.sk_key_mappings, &search_km,
            NULL);
        if (found_km == NULL) {
                ret = SET_ERROR(ENOENT);
                goto error_unlock;
        }

        if (found_km && tag)
                refcount_add(&found_km->km_key->dck_holds, tag);

        rw_exit(&spa->spa_keystore.sk_km_lock);

        if (dck_out != NULL)
                *dck_out = found_km->km_key;
        return (0);

error_unlock:
        rw_exit(&spa->spa_keystore.sk_km_lock);

        if (dck_out != NULL)
                *dck_out = NULL;
        return (ret);
}

static int
dmu_objset_check_wkey_loaded(dsl_dir_t *dd)
{
        int ret;
        dsl_wrapping_key_t *wkey = NULL;

        ret = spa_keystore_wkey_hold_dd(dd->dd_pool->dp_spa, dd, FTAG,
            &wkey);
        if (ret != 0)
                return (SET_ERROR(EACCES));

        dsl_wrapping_key_rele(wkey, FTAG);

        return (0);
}

static zfs_keystatus_t
dsl_dataset_get_keystatus(dsl_dir_t *dd)
{
        /* check if this dd has a has a dsl key */
        if (dd->dd_crypto_obj == 0)
                return (ZFS_KEYSTATUS_NONE);

        return (dmu_objset_check_wkey_loaded(dd) == 0 ?
            ZFS_KEYSTATUS_AVAILABLE : ZFS_KEYSTATUS_UNAVAILABLE);
}

static int
dsl_dir_get_crypt(dsl_dir_t *dd, uint64_t *crypt)
{
        if (dd->dd_crypto_obj == 0) {
                *crypt = ZIO_CRYPT_OFF;
                return (0);
        }

        return (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            DSL_CRYPTO_KEY_CRYPTO_SUITE, 8, 1, crypt));
}

static void
dsl_crypto_key_sync_impl(objset_t *mos, uint64_t dckobj, uint64_t crypt,
    uint64_t root_ddobj, uint64_t guid, uint8_t *iv, uint8_t *mac,
    uint8_t *keydata, uint8_t *hmac_keydata, uint64_t keyformat,
    uint64_t salt, uint64_t iters, dmu_tx_t *tx)
{
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_CRYPTO_SUITE, 8, 1,
            &crypt, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_ROOT_DDOBJ, 8, 1,
            &root_ddobj, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_GUID, 8, 1,
            &guid, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_IV, 1, WRAPPING_IV_LEN,
            iv, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_MAC, 1, WRAPPING_MAC_LEN,
            mac, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_MASTER_KEY, 1,
            MASTER_KEY_MAX_LEN, keydata, tx));
        VERIFY0(zap_update(mos, dckobj, DSL_CRYPTO_KEY_HMAC_KEY, 1,
            SHA512_HMAC_KEYLEN, hmac_keydata, tx));
        VERIFY0(zap_update(mos, dckobj, zfs_prop_to_name(ZFS_PROP_KEYFORMAT),
            8, 1, &keyformat, tx));
        VERIFY0(zap_update(mos, dckobj, zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT),
            8, 1, &salt, tx));
        VERIFY0(zap_update(mos, dckobj, zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS),
            8, 1, &iters, tx));
}

static void
dsl_crypto_key_sync(dsl_crypto_key_t *dck, dmu_tx_t *tx)
{
        zio_crypt_key_t *key = &dck->dck_key;
        dsl_wrapping_key_t *wkey = dck->dck_wkey;
        uint8_t keydata[MASTER_KEY_MAX_LEN];
        uint8_t hmac_keydata[SHA512_HMAC_KEYLEN];
        uint8_t iv[WRAPPING_IV_LEN];
        uint8_t mac[WRAPPING_MAC_LEN];

        ASSERT(dmu_tx_is_syncing(tx));
        ASSERT3U(key->zk_crypt, <, ZIO_CRYPT_FUNCTIONS);

        /* encrypt and store the keys along with the IV and MAC */
        VERIFY0(zio_crypt_key_wrap(&dck->dck_wkey->wk_key, key, iv, mac,
            keydata, hmac_keydata));

        /* update the ZAP with the obtained values */
        dsl_crypto_key_sync_impl(tx->tx_pool->dp_meta_objset, dck->dck_obj,
            key->zk_crypt, wkey->wk_ddobj, key->zk_guid, iv, mac, keydata,
            hmac_keydata, wkey->wk_keyformat, wkey->wk_salt, wkey->wk_iters,
            tx);
}

typedef struct spa_keystore_change_key_args {
        const char *skcka_dsname;
        dsl_crypto_params_t *skcka_cp;
} spa_keystore_change_key_args_t;

static int
spa_keystore_change_key_check(void *arg, dmu_tx_t *tx)
{
        int ret;
        dsl_dir_t *dd = NULL;
        dsl_pool_t *dp = dmu_tx_pool(tx);
        spa_keystore_change_key_args_t *skcka = arg;
        dsl_crypto_params_t *dcp = skcka->skcka_cp;
        uint64_t rddobj;

        /* check for the encryption feature */
        if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ENCRYPTION)) {
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        /* check for valid key change command */
        if (dcp->cp_cmd != DCP_CMD_NEW_KEY &&
            dcp->cp_cmd != DCP_CMD_INHERIT &&
            dcp->cp_cmd != DCP_CMD_FORCE_NEW_KEY &&
            dcp->cp_cmd != DCP_CMD_FORCE_INHERIT) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* hold the dd */
        ret = dsl_dir_hold(dp, skcka->skcka_dsname, FTAG, &dd, NULL);
        if (ret != 0)
                goto error;

        /* verify that the dataset is encrypted */
        if (dd->dd_crypto_obj == 0) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* clones must always use their origin's key */
        if (dsl_dir_is_clone(dd)) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* lookup the ddobj we are inheriting the keylocation from */
        ret = dsl_dir_get_encryption_root_ddobj(dd, &rddobj);
        if (ret != 0)
                goto error;

        /* Handle inheritence */
        if (dcp->cp_cmd == DCP_CMD_INHERIT ||
            dcp->cp_cmd == DCP_CMD_FORCE_INHERIT) {
                /* no other encryption params should be given */
                if (dcp->cp_crypt != ZIO_CRYPT_INHERIT ||
                    dcp->cp_keylocation != NULL ||
                    dcp->cp_wkey != NULL) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                /* check that this is an encryption root */
                if (dd->dd_object != rddobj) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                /* check that the parent is encrypted */
                if (dd->dd_parent->dd_crypto_obj == 0) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                /* if we are rewrapping check that both keys are loaded */
                if (dcp->cp_cmd == DCP_CMD_INHERIT) {
                        ret = dmu_objset_check_wkey_loaded(dd);
                        if (ret != 0)
                                goto error;

                        ret = dmu_objset_check_wkey_loaded(dd->dd_parent);
                        if (ret != 0)
                                goto error;
                }

                dsl_dir_rele(dd, FTAG);
                return (0);
        }

        /* handle forcing an encryption root without rewrapping */
        if (dcp->cp_cmd == DCP_CMD_FORCE_NEW_KEY) {
                /* no other encryption params should be given */
                if (dcp->cp_crypt != ZIO_CRYPT_INHERIT ||
                    dcp->cp_keylocation != NULL ||
                    dcp->cp_wkey != NULL) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                /* check that this is not an encryption root */
                if (dd->dd_object == rddobj) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }

                dsl_dir_rele(dd, FTAG);
                return (0);
        }

        /* crypt cannot be changed after creation */
        if (dcp->cp_crypt != ZIO_CRYPT_INHERIT) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* we are not inheritting our parent's wkey so we need one ourselves */
        if (dcp->cp_wkey == NULL) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* check for a valid keyformat for the new wrapping key */
        if (dcp->cp_wkey->wk_keyformat >= ZFS_KEYFORMAT_FORMATS ||
            dcp->cp_wkey->wk_keyformat == ZFS_KEYFORMAT_NONE) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /*
         * If this dataset is not currently an encryption root we need a new
         * keylocation for this dataset's new wrapping key. Otherwise we can
         * just keep the one we already had.
         */
        if (dd->dd_object != rddobj && dcp->cp_keylocation == NULL) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* check that the keylocation is valid if it is not NULL */
        if (dcp->cp_keylocation != NULL &&
            !zfs_prop_valid_keylocation(dcp->cp_keylocation, B_TRUE)) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* passphrases require pbkdf2 salt and iters */
        if (dcp->cp_wkey->wk_keyformat == ZFS_KEYFORMAT_PASSPHRASE) {
                if (dcp->cp_wkey->wk_salt == 0 ||
                    dcp->cp_wkey->wk_iters < MIN_PBKDF2_ITERATIONS) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }
        } else {
                if (dcp->cp_wkey->wk_salt != 0 || dcp->cp_wkey->wk_iters != 0) {
                        ret = SET_ERROR(EINVAL);
                        goto error;
                }
        }

        /* make sure the dd's wkey is loaded */
        ret = dmu_objset_check_wkey_loaded(dd);
        if (ret != 0)
                goto error;

        dsl_dir_rele(dd, FTAG);

        return (0);

error:
        if (dd != NULL)
                dsl_dir_rele(dd, FTAG);

        return (ret);
}


static void
spa_keystore_change_key_sync_impl(uint64_t rddobj, uint64_t ddobj,
    uint64_t new_rddobj, dsl_wrapping_key_t *wkey, dmu_tx_t *tx)
{
        zap_cursor_t *zc;
        zap_attribute_t *za;
        dsl_pool_t *dp = dmu_tx_pool(tx);
        dsl_dir_t *dd = NULL;
        dsl_crypto_key_t *dck = NULL;
        uint64_t curr_rddobj;

        ASSERT(RW_WRITE_HELD(&dp->dp_spa->spa_keystore.sk_wkeys_lock));

        /* hold the dd */
        VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));

        /* ignore hidden dsl dirs */
        if (dd->dd_myname[0] == '$' || dd->dd_myname[0] == '%') {
                dsl_dir_rele(dd, FTAG);
                return;
        }

        /*
         * Stop recursing if this dsl dir didn't inherit from the root
         * or if this dd is a clone.
         */
        VERIFY0(dsl_dir_get_encryption_root_ddobj(dd, &curr_rddobj));
        if (curr_rddobj != rddobj || dsl_dir_is_clone(dd)) {
                dsl_dir_rele(dd, FTAG);
                return;
        }

        /*
         * If we don't have a wrapping key just update the dck to reflect the
         * new encryption root. Otherwise rewrap the entire dck and re-sync it
         * to disk.
         */
        if (wkey == NULL) {
                VERIFY0(zap_update(dp->dp_meta_objset, dd->dd_crypto_obj,
                    DSL_CRYPTO_KEY_ROOT_DDOBJ, 8, 1, &new_rddobj, tx));
        } else {
                VERIFY0(spa_keystore_dsl_key_hold_dd(dp->dp_spa, dd,
                    FTAG, &dck));
                dsl_wrapping_key_hold(wkey, dck);
                dsl_wrapping_key_rele(dck->dck_wkey, dck);
                dck->dck_wkey = wkey;
                dsl_crypto_key_sync(dck, tx);
                spa_keystore_dsl_key_rele(dp->dp_spa, dck, FTAG);
        }

        zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP);
        za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);

        /* Recurse into all child dsl dirs. */
        for (zap_cursor_init(zc, dp->dp_meta_objset,
            dsl_dir_phys(dd)->dd_child_dir_zapobj);
            zap_cursor_retrieve(zc, za) == 0;
            zap_cursor_advance(zc)) {
                spa_keystore_change_key_sync_impl(rddobj,
                    za->za_first_integer, new_rddobj, wkey, tx);
        }
        zap_cursor_fini(zc);

        kmem_free(za, sizeof (zap_attribute_t));
        kmem_free(zc, sizeof (zap_cursor_t));

        dsl_dir_rele(dd, FTAG);
}

static void
spa_keystore_change_key_sync(void *arg, dmu_tx_t *tx)
{
        dsl_dataset_t *ds;
        avl_index_t where;
        dsl_pool_t *dp = dmu_tx_pool(tx);
        spa_t *spa = dp->dp_spa;
        spa_keystore_change_key_args_t *skcka = arg;
        dsl_crypto_params_t *dcp = skcka->skcka_cp;
        dsl_wrapping_key_t *wkey = NULL, *found_wkey;
        dsl_wrapping_key_t wkey_search;
        char *keylocation = dcp->cp_keylocation;
        uint64_t rddobj, new_rddobj;

        /* create and initialize the wrapping key */
        VERIFY0(dsl_dataset_hold(dp, skcka->skcka_dsname, FTAG, &ds));
        ASSERT(!ds->ds_is_snapshot);

        if (dcp->cp_cmd == DCP_CMD_NEW_KEY ||
            dcp->cp_cmd == DCP_CMD_FORCE_NEW_KEY) {
                /*
                 * We are changing to a new wkey. Set additional properties
                 * which can be sent along with this ioctl. Note that this
                 * command can set keylocation even if it can't normally be
                 * set via 'zfs set' due to a non-local keylocation.
                 */
                if (dcp->cp_cmd == DCP_CMD_NEW_KEY) {
                        wkey = dcp->cp_wkey;
                        wkey->wk_ddobj = ds->ds_dir->dd_object;
                } else {
                        keylocation = "prompt";
                }

                if (keylocation != NULL) {
                        dsl_prop_set_sync_impl(ds,
                            zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
                            ZPROP_SRC_LOCAL, 1, strlen(keylocation) + 1,
                            keylocation, tx);
                }

                VERIFY0(dsl_dir_get_encryption_root_ddobj(ds->ds_dir, &rddobj));
                new_rddobj = ds->ds_dir->dd_object;
        } else {
                /*
                 * We are inheritting the parent's wkey. Unset any local
                 * keylocation and grab a reference to the wkey.
                 */
                if (dcp->cp_cmd == DCP_CMD_INHERIT) {
                        VERIFY0(spa_keystore_wkey_hold_dd(spa,
                            ds->ds_dir->dd_parent, FTAG, &wkey));
                }

                dsl_prop_set_sync_impl(ds,
                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION), ZPROP_SRC_NONE,
                    0, 0, NULL, tx);

                rddobj = ds->ds_dir->dd_object;
                VERIFY0(dsl_dir_get_encryption_root_ddobj(ds->ds_dir->dd_parent,
                    &new_rddobj));
        }

        if (wkey == NULL) {
                ASSERT(dcp->cp_cmd == DCP_CMD_FORCE_INHERIT ||
                    dcp->cp_cmd == DCP_CMD_FORCE_NEW_KEY);
        }

        rw_enter(&spa->spa_keystore.sk_wkeys_lock, RW_WRITER);

        /* recurse through all children and rewrap their keys */
        spa_keystore_change_key_sync_impl(rddobj, ds->ds_dir->dd_object,
            new_rddobj, wkey, tx);

        /*
         * All references to the old wkey should be released now (if it
         * existed). Replace the wrapping key.
         */
        wkey_search.wk_ddobj = ds->ds_dir->dd_object;
        found_wkey = avl_find(&spa->spa_keystore.sk_wkeys, &wkey_search, NULL);
        if (found_wkey != NULL) {
                ASSERT0(refcount_count(&found_wkey->wk_refcnt));
                avl_remove(&spa->spa_keystore.sk_wkeys, found_wkey);
                dsl_wrapping_key_free(found_wkey);
        }

        if (dcp->cp_cmd == DCP_CMD_NEW_KEY) {
                avl_find(&spa->spa_keystore.sk_wkeys, wkey, &where);
                avl_insert(&spa->spa_keystore.sk_wkeys, wkey, where);
        } else if (wkey != NULL) {
                dsl_wrapping_key_rele(wkey, FTAG);
        }

        rw_exit(&spa->spa_keystore.sk_wkeys_lock);

        dsl_dataset_rele(ds, FTAG);
}

int
spa_keystore_change_key(const char *dsname, dsl_crypto_params_t *dcp)
{
        spa_keystore_change_key_args_t skcka;

        /* initialize the args struct */
        skcka.skcka_dsname = dsname;
        skcka.skcka_cp = dcp;

        /*
         * Perform the actual work in syncing context. The blocks modified
         * here could be calculated but it would require holding the pool
         * lock and tarversing all of the datasets that will have their keys
         * changed.
         */
        return (dsl_sync_task(dsname, spa_keystore_change_key_check,
            spa_keystore_change_key_sync, &skcka, 15,
            ZFS_SPACE_CHECK_RESERVED));
}

int
dsl_dir_rename_crypt_check(dsl_dir_t *dd, dsl_dir_t *newparent)
{
        int ret;
        uint64_t curr_rddobj, parent_rddobj;

        if (dd->dd_crypto_obj == 0) {
                /* children of encrypted parents must be encrypted */
                if (newparent->dd_crypto_obj != 0) {
                        ret = SET_ERROR(EACCES);
                        goto error;
                }

                return (0);
        }

        ret = dsl_dir_get_encryption_root_ddobj(dd, &curr_rddobj);
        if (ret != 0)
                goto error;

        /*
         * if this is not an encryption root, we must make sure we are not
         * moving dd to a new encryption root
         */
        if (dd->dd_object != curr_rddobj) {
                ret = dsl_dir_get_encryption_root_ddobj(newparent,
                    &parent_rddobj);
                if (ret != 0)
                        goto error;

                if (parent_rddobj != curr_rddobj) {
                        ret = SET_ERROR(EACCES);
                        goto error;
                }
        }

        return (0);

error:
        return (ret);
}

/*
 * Check to make sure that a promote from targetdd to origindd will not require
 * any key rewraps.
 */
int
dsl_dataset_promote_crypt_check(dsl_dir_t *target, dsl_dir_t *origin)
{
        int ret;
        uint64_t rddobj, op_rddobj, tp_rddobj;

        /* If the dataset is not encrypted we don't need to check anything */
        if (origin->dd_crypto_obj == 0)
                return (0);

        /*
         * If we are not changing the first origin snapshot in a chain
         * the encryption root won't change either.
         */
        if (dsl_dir_is_clone(origin))
                return (0);

        /*
         * If the origin is the encryption root we will update
         * the DSL Crypto Key to point to the target instead.
         */
        ret = dsl_dir_get_encryption_root_ddobj(origin, &rddobj);
        if (ret != 0)
                return (ret);

        if (rddobj == origin->dd_object)
                return (0);

        /*
         * The origin is inheriting its encryption root from its parent.
         * Check that the parent of the target has the same encryption root.
         */
        ret = dsl_dir_get_encryption_root_ddobj(origin->dd_parent, &op_rddobj);
        if (ret != 0)
                return (ret);

        ret = dsl_dir_get_encryption_root_ddobj(target->dd_parent, &tp_rddobj);
        if (ret != 0)
                return (ret);

        if (op_rddobj != tp_rddobj)
                return (SET_ERROR(EACCES));

        return (0);
}

void
dsl_dataset_promote_crypt_sync(dsl_dir_t *target, dsl_dir_t *origin,
    dmu_tx_t *tx)
{
        uint64_t rddobj;
        dsl_pool_t *dp = target->dd_pool;
        dsl_dataset_t *targetds;
        dsl_dataset_t *originds;
        char *keylocation;

        if (origin->dd_crypto_obj == 0)
                return;
        if (dsl_dir_is_clone(origin))
                return;

        VERIFY0(dsl_dir_get_encryption_root_ddobj(origin, &rddobj));

        if (rddobj != origin->dd_object)
                return;

        /*
         * If the target is being promoted to the encyrption root update the
         * DSL Crypto Key and keylocation to reflect that. We also need to
         * update the DSL Crypto Keys of all children inheritting their
         * encryption root to point to the new target. Otherwise, the check
         * function ensured that the encryption root will not change.
         */
        keylocation = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);

        VERIFY0(dsl_dataset_hold_obj(dp,
            dsl_dir_phys(target)->dd_head_dataset_obj, FTAG, &targetds));
        VERIFY0(dsl_dataset_hold_obj(dp,
            dsl_dir_phys(origin)->dd_head_dataset_obj, FTAG, &originds));

        VERIFY0(dsl_prop_get_dd(origin, zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
            1, ZAP_MAXVALUELEN, keylocation, NULL, B_FALSE));
        dsl_prop_set_sync_impl(targetds, zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
            ZPROP_SRC_LOCAL, 1, strlen(keylocation) + 1, keylocation, tx);
        dsl_prop_set_sync_impl(originds, zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
            ZPROP_SRC_NONE, 0, 0, NULL, tx);

        rw_enter(&dp->dp_spa->spa_keystore.sk_wkeys_lock, RW_WRITER);
        spa_keystore_change_key_sync_impl(rddobj, origin->dd_object,
            target->dd_object, NULL, tx);
        rw_exit(&dp->dp_spa->spa_keystore.sk_wkeys_lock);

        dsl_dataset_rele(targetds, FTAG);
        dsl_dataset_rele(originds, FTAG);
        kmem_free(keylocation, ZAP_MAXVALUELEN);
}

int
dmu_objset_clone_crypt_check(dsl_dir_t *parentdd, dsl_dir_t *origindd)
{
        int ret;
        uint64_t pcrypt, crypt;

        /*
         * Check that we are not making an unencrypted child of an
         * encrypted parent.
         */
        ret = dsl_dir_get_crypt(parentdd, &pcrypt);
        if (ret != 0)
                return (ret);

        ret = dsl_dir_get_crypt(origindd, &crypt);
        if (ret != 0)
                return (ret);

        ASSERT3U(pcrypt, !=, ZIO_CRYPT_INHERIT);
        ASSERT3U(crypt, !=, ZIO_CRYPT_INHERIT);

        if (crypt == ZIO_CRYPT_OFF && pcrypt != ZIO_CRYPT_OFF)
                return (SET_ERROR(EINVAL));

        return (0);
}


int
dmu_objset_create_crypt_check(dsl_dir_t *parentdd, dsl_crypto_params_t *dcp)
{
        int ret;
        uint64_t pcrypt, crypt;

        if (dcp->cp_cmd != DCP_CMD_NONE)
                return (SET_ERROR(EINVAL));

        if (parentdd != NULL) {
                ret = dsl_dir_get_crypt(parentdd, &pcrypt);
                if (ret != 0)
                        return (ret);
        } else {
                pcrypt = ZIO_CRYPT_OFF;
        }

        crypt = (dcp->cp_crypt == ZIO_CRYPT_INHERIT) ? pcrypt : dcp->cp_crypt;

        ASSERT3U(pcrypt, !=, ZIO_CRYPT_INHERIT);
        ASSERT3U(crypt, !=, ZIO_CRYPT_INHERIT);

        /*
         * We can't create an unencrypted child of an encrypted parent
         * under any circumstances.
         */
        if (crypt == ZIO_CRYPT_OFF && pcrypt != ZIO_CRYPT_OFF)
                return (SET_ERROR(EINVAL));

        /* check for valid dcp with no encryption (inherited or local) */
        if (crypt == ZIO_CRYPT_OFF) {
                /* Must not specify encryption params */
                if (dcp->cp_wkey != NULL ||
                    (dcp->cp_keylocation != NULL &&
                    strcmp(dcp->cp_keylocation, "none") != 0))
                        return (SET_ERROR(EINVAL));

                return (0);
        }

        /*
         * We will now definitely be encrypting. Check the feature flag. When
         * creating the pool the caller will check this for us since we won't
         * technically have the fetaure activated yet.
         */
        if (parentdd != NULL &&
            !spa_feature_is_enabled(parentdd->dd_pool->dp_spa,
            SPA_FEATURE_ENCRYPTION)) {
                return (SET_ERROR(EOPNOTSUPP));
        }

        /* handle inheritence */
        if (dcp->cp_wkey == NULL) {
                ASSERT3P(parentdd, !=, NULL);

                /* key must be fully unspecified */
                if (dcp->cp_keylocation != NULL)
                        return (SET_ERROR(EINVAL));

                /* parent must have a key to inherit */
                if (pcrypt == ZIO_CRYPT_OFF)
                        return (SET_ERROR(EINVAL));

                /* check for parent key */
                ret = dmu_objset_check_wkey_loaded(parentdd);
                if (ret != 0)
                        return (ret);

                return (0);
        }

        /* At this point we should have a fully specified key. Check location */
        if (dcp->cp_keylocation == NULL ||
            !zfs_prop_valid_keylocation(dcp->cp_keylocation, B_TRUE))
                return (SET_ERROR(EINVAL));

        /* Must have fully specified keyformat */
        switch (dcp->cp_wkey->wk_keyformat) {
        case ZFS_KEYFORMAT_HEX:
        case ZFS_KEYFORMAT_RAW:
                /* requires no pbkdf2 iters and salt */
                if (dcp->cp_wkey->wk_salt != 0 || dcp->cp_wkey->wk_iters != 0)
                        return (SET_ERROR(EINVAL));
                break;
        case ZFS_KEYFORMAT_PASSPHRASE:
                /* requires pbkdf2 iters and salt */
                if (dcp->cp_wkey->wk_salt == 0 ||
                    dcp->cp_wkey->wk_iters < MIN_PBKDF2_ITERATIONS)
                        return (SET_ERROR(EINVAL));
                break;
        case ZFS_KEYFORMAT_NONE:
        default:
                /* keyformat must be specified and valid */
                return (SET_ERROR(EINVAL));
        }

        return (0);
}

void
dsl_dataset_create_crypt_sync(uint64_t dsobj, dsl_dir_t *dd,
    dsl_dataset_t *origin, dsl_crypto_params_t *dcp, dmu_tx_t *tx)
{
        dsl_pool_t *dp = dd->dd_pool;
        uint64_t crypt;
        dsl_wrapping_key_t *wkey;

        /* clones always use their origin's wrapping key */
        if (dsl_dir_is_clone(dd)) {
                ASSERT3P(dcp, ==, NULL);

                /*
                 * If this is an encrypted clone we just need to clone the
                 * dck into dd. Zapify the dd so we can do that.
                 */
                if (origin->ds_dir->dd_crypto_obj != 0) {
                        dmu_buf_will_dirty(dd->dd_dbuf, tx);
                        dsl_dir_zapify(dd, tx);

                        dd->dd_crypto_obj =
                            dsl_crypto_key_clone_sync(origin->ds_dir, tx);
                        VERIFY0(zap_add(dp->dp_meta_objset, dd->dd_object,
                            DD_FIELD_CRYPTO_KEY_OBJ, sizeof (uint64_t), 1,
                            &dd->dd_crypto_obj, tx));
                }

                return;
        }

        /*
         * A NULL dcp at this point indicates this is the origin dataset
         * which does not have an objset to encrypt. Raw receives will handle
         * encryption seperately later. In both cases we can simply return.
         */
        if (dcp == NULL || dcp->cp_cmd == DCP_CMD_RAW_RECV)
                return;

        crypt = dcp->cp_crypt;
        wkey = dcp->cp_wkey;

        /* figure out the effective crypt */
        if (crypt == ZIO_CRYPT_INHERIT && dd->dd_parent != NULL)
                VERIFY0(dsl_dir_get_crypt(dd->dd_parent, &crypt));

        /* if we aren't doing encryption just return */
        if (crypt == ZIO_CRYPT_OFF || crypt == ZIO_CRYPT_INHERIT)
                return;

        /* zapify the dd so that we can add the crypto key obj to it */
        dmu_buf_will_dirty(dd->dd_dbuf, tx);
        dsl_dir_zapify(dd, tx);

        /* use the new key if given or inherit from the parent */
        if (wkey == NULL) {
                VERIFY0(spa_keystore_wkey_hold_dd(dp->dp_spa,
                    dd->dd_parent, FTAG, &wkey));
        } else {
                wkey->wk_ddobj = dd->dd_object;
        }

        ASSERT3P(wkey, !=, NULL);

        /* Create or clone the DSL crypto key and activate the feature */
        dd->dd_crypto_obj = dsl_crypto_key_create_sync(crypt, wkey, tx);
        VERIFY0(zap_add(dp->dp_meta_objset, dd->dd_object,
            DD_FIELD_CRYPTO_KEY_OBJ, sizeof (uint64_t), 1, &dd->dd_crypto_obj,
            tx));
        dsl_dataset_activate_feature(dsobj, SPA_FEATURE_ENCRYPTION, tx);

        /*
         * If we inherited the wrapping key we release our reference now.
         * Otherwise, this is a new key and we need to load it into the
         * keystore.
         */
        if (dcp->cp_wkey == NULL) {
                dsl_wrapping_key_rele(wkey, FTAG);
        } else {
                VERIFY0(spa_keystore_load_wkey_impl(dp->dp_spa, wkey));
        }
}

typedef struct dsl_crypto_recv_key_arg {
        uint64_t dcrka_dsobj;
        nvlist_t *dcrka_nvl;
        dmu_objset_type_t dcrka_ostype;
} dsl_crypto_recv_key_arg_t;

int
dsl_crypto_recv_key_check(void *arg, dmu_tx_t *tx)
{
        int ret;
        objset_t *mos = tx->tx_pool->dp_meta_objset;
        objset_t *os;
        dnode_t *mdn;
        dsl_crypto_recv_key_arg_t *dcrka = arg;
        nvlist_t *nvl = dcrka->dcrka_nvl;
        dsl_dataset_t *ds = NULL;
        uint8_t *buf = NULL;
        uint_t len;
        uint64_t intval, guid, nlevels, blksz, ibs, nblkptr, maxblkid, version;
        boolean_t is_passphrase = B_FALSE;

        ret = dsl_dataset_hold_obj(tx->tx_pool, dcrka->dcrka_dsobj, FTAG, &ds);
        if (ret != 0)
                goto error;

        ASSERT(dsl_dataset_phys(ds)->ds_flags & DS_FLAG_INCONSISTENT);

        /*
         * Read and check all the encryption values from the nvlist. We need
         * all of the fields of a DSL Crypto Key, as well as a fully specified
         * wrapping key.
         */
        ret = nvlist_lookup_uint64(nvl, DSL_CRYPTO_KEY_CRYPTO_SUITE, &intval);
        if (ret != 0 || intval >= ZIO_CRYPT_FUNCTIONS ||
            intval <= ZIO_CRYPT_OFF) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, DSL_CRYPTO_KEY_GUID, &intval);
        if (ret != 0) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /*
         * If this is an incremental receive make sure the given key guid
         * matches the one we already have.
         */
        if (ds->ds_dir->dd_crypto_obj != 0) {
                ret = zap_lookup(mos, ds->ds_dir->dd_crypto_obj,
                    DSL_CRYPTO_KEY_GUID, 8, 1, &guid);
                if (ret != 0)
                        goto error;

                if (intval != guid) {
                        ret = SET_ERROR(EACCES);
                        goto error;
                }
        }

        ret = nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_MASTER_KEY,
            &buf, &len);
        if (ret != 0 || len != MASTER_KEY_MAX_LEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_HMAC_KEY,
            &buf, &len);
        if (ret != 0 || len != SHA512_HMAC_KEYLEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_IV, &buf, &len);
        if (ret != 0 || len != WRAPPING_IV_LEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_MAC, &buf, &len);
        if (ret != 0 || len != WRAPPING_MAC_LEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /*
         * We don't support receiving old on-disk formats. The version 0
         * implementation protected several fields in an objset that were
         * not always portable during a raw receive. As a result, we call
         * the old version an on-disk errata #3.
         */
        ret = nvlist_lookup_uint64(nvl, DSL_CRYPTO_KEY_VERSION, &version);
        if (ret != 0 || version != ZIO_CRYPT_KEY_CURRENT_VERSION) {
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        ret = nvlist_lookup_uint8_array(nvl, "portable_mac", &buf, &len);
        if (ret != 0 || len != ZIO_OBJSET_MAC_LEN) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, zfs_prop_to_name(ZFS_PROP_KEYFORMAT),
            &intval);
        if (ret != 0 || intval >= ZFS_KEYFORMAT_FORMATS ||
            intval == ZFS_KEYFORMAT_NONE) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        is_passphrase = (intval == ZFS_KEYFORMAT_PASSPHRASE);

        /*
         * for raw receives we allow any number of pbkdf2iters since there
         * won't be a chance for the user to change it.
         */
        ret = nvlist_lookup_uint64(nvl, zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS),
            &intval);
        if (ret != 0 || (is_passphrase == (intval == 0))) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT),
            &intval);
        if (ret != 0 || (is_passphrase == (intval == 0))) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        /* raw receives also need info about the structure of the metadnode */
        ret = nvlist_lookup_uint64(nvl, "mdn_checksum", &intval);
        if (ret != 0 || intval >= ZIO_CHECKSUM_LEGACY_FUNCTIONS) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_compress", &intval);
        if (ret != 0 || intval >= ZIO_COMPRESS_LEGACY_FUNCTIONS) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_nlevels", &nlevels);
        if (ret != 0 || nlevels > DN_MAX_LEVELS) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_blksz", &blksz);
        if (ret != 0 || blksz < SPA_MINBLOCKSIZE) {
                ret = SET_ERROR(EINVAL);
                goto error;
        } else if (blksz > spa_maxblocksize(tx->tx_pool->dp_spa)) {
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_indblkshift", &ibs);
        if (ret != 0 || ibs < DN_MIN_INDBLKSHIFT ||
            ibs > DN_MAX_INDBLKSHIFT) {
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_nblkptr", &nblkptr);
        if (ret != 0 || nblkptr != DN_MAX_NBLKPTR) {
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        ret = nvlist_lookup_uint64(nvl, "mdn_maxblkid", &maxblkid);
        if (ret != 0) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }

        ret = dmu_objset_from_ds(ds, &os);
        if (ret != 0)
                goto error;

        /*
         * Useraccounting is not portable and must be done with the keys loaded.
         * Therefore, whenever we do any kind of receive the useraccounting
         * must not be present.
         */
        ASSERT0(os->os_flags & OBJSET_FLAG_USERACCOUNTING_COMPLETE);
        ASSERT0(os->os_flags & OBJSET_FLAG_USEROBJACCOUNTING_COMPLETE);

        mdn = DMU_META_DNODE(os);

        /*
         * If we already created the objset, make sure its unchangable
         * properties match the ones received in the nvlist.
         */
        rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
        if (!BP_IS_HOLE(dsl_dataset_get_blkptr(ds)) &&
            (mdn->dn_nlevels != nlevels || mdn->dn_datablksz != blksz ||
            mdn->dn_indblkshift != ibs || mdn->dn_nblkptr != nblkptr)) {
                ret = SET_ERROR(EINVAL);
                goto error;
        }
        rrw_exit(&ds->ds_bp_rwlock, FTAG);

        dsl_dataset_rele(ds, FTAG);
        return (0);

error:
        if (ds != NULL)
                dsl_dataset_rele(ds, FTAG);
        return (ret);
}

static void
dsl_crypto_recv_key_sync(void *arg, dmu_tx_t *tx)
{
        dsl_crypto_recv_key_arg_t *dcrka = arg;
        uint64_t dsobj = dcrka->dcrka_dsobj;
        nvlist_t *nvl = dcrka->dcrka_nvl;
        dsl_pool_t *dp = tx->tx_pool;
        objset_t *mos = dp->dp_meta_objset;
        dsl_dataset_t *ds;
        objset_t *os;
        dnode_t *mdn;
        uint8_t *keydata, *hmac_keydata, *iv, *mac, *portable_mac;
        uint_t len;
        uint64_t rddobj, one = 1;
        uint64_t version = ZIO_CRYPT_KEY_CURRENT_VERSION;
        uint64_t crypt, guid, keyformat, iters, salt;
        uint64_t compress, checksum, nlevels, blksz, ibs, maxblkid;
        char *keylocation = "prompt";

        VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
        VERIFY0(dmu_objset_from_ds(ds, &os));
        mdn = DMU_META_DNODE(os);

        /* lookup the values we need to create the DSL Crypto Key and objset */
        crypt = fnvlist_lookup_uint64(nvl, DSL_CRYPTO_KEY_CRYPTO_SUITE);
        guid = fnvlist_lookup_uint64(nvl, DSL_CRYPTO_KEY_GUID);
        keyformat = fnvlist_lookup_uint64(nvl,
            zfs_prop_to_name(ZFS_PROP_KEYFORMAT));
        iters = fnvlist_lookup_uint64(nvl,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS));
        salt = fnvlist_lookup_uint64(nvl,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT));
        VERIFY0(nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_MASTER_KEY,
            &keydata, &len));
        VERIFY0(nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_HMAC_KEY,
            &hmac_keydata, &len));
        VERIFY0(nvlist_lookup_uint8_array(nvl, "portable_mac", &portable_mac,
            &len));
        VERIFY0(nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_IV, &iv, &len));
        VERIFY0(nvlist_lookup_uint8_array(nvl, DSL_CRYPTO_KEY_MAC, &mac, &len));
        compress = fnvlist_lookup_uint64(nvl, "mdn_compress");
        checksum = fnvlist_lookup_uint64(nvl, "mdn_checksum");
        nlevels = fnvlist_lookup_uint64(nvl, "mdn_nlevels");
        blksz = fnvlist_lookup_uint64(nvl, "mdn_blksz");
        ibs = fnvlist_lookup_uint64(nvl, "mdn_indblkshift");
        maxblkid = fnvlist_lookup_uint64(nvl, "mdn_maxblkid");

        /* if we haven't created an objset for the ds yet, do that now */
        rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
        if (BP_IS_HOLE(dsl_dataset_get_blkptr(ds))) {
                (void) dmu_objset_create_impl_dnstats(dp->dp_spa, ds,
                    dsl_dataset_get_blkptr(ds), dcrka->dcrka_ostype, nlevels,
                    blksz, ibs, tx);
        }
        rrw_exit(&ds->ds_bp_rwlock, FTAG);

        /*
         * Set the portable MAC. The local MAC will always be zero since the
         * incoming data will all be portable and user accounting will be
         * deferred until the next mount. Afterwards, flag the os to be
         * written out raw next time.
         */
        arc_release(os->os_phys_buf, &os->os_phys_buf);
        bcopy(portable_mac, os->os_phys->os_portable_mac, ZIO_OBJSET_MAC_LEN);
        bzero(os->os_phys->os_local_mac, ZIO_OBJSET_MAC_LEN);
        os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;

        /* set metadnode compression and checksum */
        mdn->dn_compress = compress;
        mdn->dn_checksum = checksum;

        rw_enter(&mdn->dn_struct_rwlock, RW_WRITER);
        dnode_new_blkid(mdn, maxblkid, tx, B_FALSE);
        rw_exit(&mdn->dn_struct_rwlock);

        dsl_dataset_dirty(ds, tx);

        /* if this is a new dataset setup the DSL Crypto Key. */
        if (ds->ds_dir->dd_crypto_obj == 0) {
                /* zapify the dsl dir so we can add the key object to it */
                dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
                dsl_dir_zapify(ds->ds_dir, tx);

                /* create the DSL Crypto Key on disk and activate the feature */
                ds->ds_dir->dd_crypto_obj = zap_create(mos,
                    DMU_OTN_ZAP_METADATA, DMU_OT_NONE, 0, tx);
                VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
                    ds->ds_dir->dd_crypto_obj, DSL_CRYPTO_KEY_REFCOUNT,
                    sizeof (uint64_t), 1, &one, tx));
                VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
                    ds->ds_dir->dd_crypto_obj, DSL_CRYPTO_KEY_VERSION,
                    sizeof (uint64_t), 1, &version, tx));

                dsl_dataset_activate_feature(dsobj, SPA_FEATURE_ENCRYPTION, tx);
                ds->ds_feature_inuse[SPA_FEATURE_ENCRYPTION] = B_TRUE;

                /* save the dd_crypto_obj on disk */
                VERIFY0(zap_add(mos, ds->ds_dir->dd_object,
                    DD_FIELD_CRYPTO_KEY_OBJ, sizeof (uint64_t), 1,
                    &ds->ds_dir->dd_crypto_obj, tx));

                /*
                 * Set the keylocation to prompt by default. If keylocation
                 * has been provided via the properties, this will be overriden
                 * later.
                 */
                dsl_prop_set_sync_impl(ds,
                    zfs_prop_to_name(ZFS_PROP_KEYLOCATION),
                    ZPROP_SRC_LOCAL, 1, strlen(keylocation) + 1,
                    keylocation, tx);

                rddobj = ds->ds_dir->dd_object;
        } else {
                VERIFY0(dsl_dir_get_encryption_root_ddobj(ds->ds_dir, &rddobj));
        }

        /* sync the key data to the ZAP object on disk */
        dsl_crypto_key_sync_impl(mos, ds->ds_dir->dd_crypto_obj, crypt,
            rddobj, guid, iv, mac, keydata, hmac_keydata, keyformat, salt,
            iters, tx);

        dsl_dataset_rele(ds, FTAG);
}

/*
 * This function is used to sync an nvlist representing a DSL Crypto Key and
 * the associated encryption parameters. The key will be written exactly as is
 * without wrapping it.
 */
int
dsl_crypto_recv_key(const char *poolname, uint64_t dsobj,
    dmu_objset_type_t ostype, nvlist_t *nvl)
{
        dsl_crypto_recv_key_arg_t dcrka;

        dcrka.dcrka_dsobj = dsobj;
        dcrka.dcrka_nvl = nvl;
        dcrka.dcrka_ostype = ostype;

        return (dsl_sync_task(poolname, dsl_crypto_recv_key_check,
            dsl_crypto_recv_key_sync, &dcrka, 1, ZFS_SPACE_CHECK_NORMAL));
}

int
dsl_crypto_populate_key_nvlist(dsl_dataset_t *ds, nvlist_t **nvl_out)
{
        int ret;
        objset_t *os;
        dnode_t *mdn;
        uint64_t rddobj;
        nvlist_t *nvl = NULL;
        uint64_t dckobj = ds->ds_dir->dd_crypto_obj;
        dsl_dir_t *rdd = NULL;
        dsl_pool_t *dp = ds->ds_dir->dd_pool;
        objset_t *mos = dp->dp_meta_objset;
        uint64_t crypt = 0, guid = 0, format = 0;
        uint64_t iters = 0, salt = 0, version = 0;
        uint8_t raw_keydata[MASTER_KEY_MAX_LEN];
        uint8_t raw_hmac_keydata[SHA512_HMAC_KEYLEN];
        uint8_t iv[WRAPPING_IV_LEN];
        uint8_t mac[WRAPPING_MAC_LEN];

        ASSERT(dckobj != 0);

        VERIFY0(dmu_objset_from_ds(ds, &os));
        mdn = DMU_META_DNODE(os);

        ret = nvlist_alloc(&nvl, NV_UNIQUE_NAME, KM_SLEEP);
        if (ret != 0)
                goto error;

        /* lookup values from the DSL Crypto Key */
        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_CRYPTO_SUITE, 8, 1,
            &crypt);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_GUID, 8, 1, &guid);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_MASTER_KEY, 1,
            MASTER_KEY_MAX_LEN, raw_keydata);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_HMAC_KEY, 1,
            SHA512_HMAC_KEYLEN, raw_hmac_keydata);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_IV, 1, WRAPPING_IV_LEN,
            iv);
        if (ret != 0)
                goto error;

        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_MAC, 1, WRAPPING_MAC_LEN,
            mac);
        if (ret != 0)
                goto error;

        /*
         * We don't support raw sends of legacy on-disk formats. See the
         * comment in dsl_crypto_recv_key_check() for details.
         */
        ret = zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_VERSION, 8, 1, &version);
        if (ret != 0 || version != ZIO_CRYPT_KEY_CURRENT_VERSION) {
                dp->dp_spa->spa_errata = ZPOOL_ERRATA_ZOL_6845_ENCRYPTION;
                ret = SET_ERROR(ENOTSUP);
                goto error;
        }

        /*
         * Lookup wrapping key properties. An early version of the code did
         * not correctly add these values to the wrapping key or the DSL
         * Crypto Key on disk for non encryption roots, so to be safe we
         * always take the slightly circuitous route of looking it up from
         * the encryption root's key.
         */
        ret = dsl_dir_get_encryption_root_ddobj(ds->ds_dir, &rddobj);
        if (ret != 0)
                goto error;

        dsl_pool_config_enter(dp, FTAG);

        ret = dsl_dir_hold_obj(dp, rddobj, NULL, FTAG, &rdd);
        if (ret != 0)
                goto error_unlock;

        ret = zap_lookup(dp->dp_meta_objset, rdd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_KEYFORMAT), 8, 1, &format);
        if (ret != 0)
                goto error_unlock;

        if (format == ZFS_KEYFORMAT_PASSPHRASE) {
                ret = zap_lookup(dp->dp_meta_objset, rdd->dd_crypto_obj,
                    zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS), 8, 1, &iters);
                if (ret != 0)
                        goto error_unlock;

                ret = zap_lookup(dp->dp_meta_objset, rdd->dd_crypto_obj,
                    zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT), 8, 1, &salt);
                if (ret != 0)
                        goto error_unlock;
        }

        dsl_dir_rele(rdd, FTAG);
        dsl_pool_config_exit(dp, FTAG);

        fnvlist_add_uint64(nvl, DSL_CRYPTO_KEY_CRYPTO_SUITE, crypt);
        fnvlist_add_uint64(nvl, DSL_CRYPTO_KEY_GUID, guid);
        fnvlist_add_uint64(nvl, DSL_CRYPTO_KEY_VERSION, version);
        VERIFY0(nvlist_add_uint8_array(nvl, DSL_CRYPTO_KEY_MASTER_KEY,
            raw_keydata, MASTER_KEY_MAX_LEN));
        VERIFY0(nvlist_add_uint8_array(nvl, DSL_CRYPTO_KEY_HMAC_KEY,
            raw_hmac_keydata, SHA512_HMAC_KEYLEN));
        VERIFY0(nvlist_add_uint8_array(nvl, DSL_CRYPTO_KEY_IV, iv,
            WRAPPING_IV_LEN));
        VERIFY0(nvlist_add_uint8_array(nvl, DSL_CRYPTO_KEY_MAC, mac,
            WRAPPING_MAC_LEN));
        VERIFY0(nvlist_add_uint8_array(nvl, "portable_mac",
            os->os_phys->os_portable_mac, ZIO_OBJSET_MAC_LEN));
        fnvlist_add_uint64(nvl, zfs_prop_to_name(ZFS_PROP_KEYFORMAT), format);
        fnvlist_add_uint64(nvl, zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS), iters);
        fnvlist_add_uint64(nvl, zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT), salt);
        fnvlist_add_uint64(nvl, "mdn_checksum", mdn->dn_checksum);
        fnvlist_add_uint64(nvl, "mdn_compress", mdn->dn_compress);
        fnvlist_add_uint64(nvl, "mdn_nlevels", mdn->dn_nlevels);
        fnvlist_add_uint64(nvl, "mdn_blksz", mdn->dn_datablksz);
        fnvlist_add_uint64(nvl, "mdn_indblkshift", mdn->dn_indblkshift);
        fnvlist_add_uint64(nvl, "mdn_nblkptr", mdn->dn_nblkptr);
        fnvlist_add_uint64(nvl, "mdn_maxblkid", mdn->dn_maxblkid);

        *nvl_out = nvl;
        return (0);

error_unlock:
        dsl_pool_config_exit(dp, FTAG);
error:
        if (rdd != NULL)
                dsl_dir_rele(rdd, FTAG);
        nvlist_free(nvl);

        *nvl_out = NULL;
        return (ret);
}

uint64_t
dsl_crypto_key_create_sync(uint64_t crypt, dsl_wrapping_key_t *wkey,
    dmu_tx_t *tx)
{
        dsl_crypto_key_t dck;
        uint64_t version = ZIO_CRYPT_KEY_CURRENT_VERSION;
        uint64_t one = 1ULL;

        ASSERT(dmu_tx_is_syncing(tx));
        ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
        ASSERT3U(crypt, >, ZIO_CRYPT_OFF);

        /* create the DSL Crypto Key ZAP object */
        dck.dck_obj = zap_create(tx->tx_pool->dp_meta_objset,
            DMU_OTN_ZAP_METADATA, DMU_OT_NONE, 0, tx);

        /* fill in the key (on the stack) and sync it to disk */
        dck.dck_wkey = wkey;
        VERIFY0(zio_crypt_key_init(crypt, &dck.dck_key));

        dsl_crypto_key_sync(&dck, tx);
        VERIFY0(zap_update(tx->tx_pool->dp_meta_objset, dck.dck_obj,
            DSL_CRYPTO_KEY_REFCOUNT, sizeof (uint64_t), 1, &one, tx));
        VERIFY0(zap_update(tx->tx_pool->dp_meta_objset, dck.dck_obj,
            DSL_CRYPTO_KEY_VERSION, sizeof (uint64_t), 1, &version, tx));

        zio_crypt_key_destroy(&dck.dck_key);
        bzero(&dck.dck_key, sizeof (zio_crypt_key_t));

        return (dck.dck_obj);
}

uint64_t
dsl_crypto_key_clone_sync(dsl_dir_t *origindd, dmu_tx_t *tx)
{
        objset_t *mos = tx->tx_pool->dp_meta_objset;

        ASSERT(dmu_tx_is_syncing(tx));

        VERIFY0(zap_increment(mos, origindd->dd_crypto_obj,
            DSL_CRYPTO_KEY_REFCOUNT, 1, tx));

        return (origindd->dd_crypto_obj);
}

void
dsl_crypto_key_destroy_sync(uint64_t dckobj, dmu_tx_t *tx)
{
        objset_t *mos = tx->tx_pool->dp_meta_objset;
        uint64_t refcnt;

        /* Decrement the refcount, destroy if this is the last reference */
        VERIFY0(zap_lookup(mos, dckobj, DSL_CRYPTO_KEY_REFCOUNT,
            sizeof (uint64_t), 1, &refcnt));

        if (refcnt != 1) {
                VERIFY0(zap_increment(mos, dckobj, DSL_CRYPTO_KEY_REFCOUNT,
                    -1, tx));
        } else {
                VERIFY0(zap_destroy(mos, dckobj, tx));
        }
}

void
dsl_dataset_crypt_stats(dsl_dataset_t *ds, nvlist_t *nv)
{
        uint64_t intval;
        dsl_dir_t *dd = ds->ds_dir;
        dsl_dir_t *enc_root;
        char buf[ZFS_MAX_DATASET_NAME_LEN];

        if (dd->dd_crypto_obj == 0)
                return;

        intval = dsl_dataset_get_keystatus(dd);
        dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_KEYSTATUS, intval);

        if (dsl_dir_get_crypt(dd, &intval) == 0)
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_ENCRYPTION, intval);
        if (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            DSL_CRYPTO_KEY_GUID, 8, 1, &intval) == 0) {
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_KEY_GUID, intval);
        }
        if (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_KEYFORMAT), 8, 1, &intval) == 0) {
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_KEYFORMAT, intval);
        }
        if (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_SALT), 8, 1, &intval) == 0) {
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_PBKDF2_SALT, intval);
        }
        if (zap_lookup(dd->dd_pool->dp_meta_objset, dd->dd_crypto_obj,
            zfs_prop_to_name(ZFS_PROP_PBKDF2_ITERS), 8, 1, &intval) == 0) {
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_PBKDF2_ITERS, intval);
        }

        if (dsl_dir_get_encryption_root_ddobj(dd, &intval) == 0) {
                VERIFY0(dsl_dir_hold_obj(dd->dd_pool, intval, NULL, FTAG,
                    &enc_root));
                dsl_dir_name(enc_root, buf);
                dsl_dir_rele(enc_root, FTAG);
                dsl_prop_nvlist_add_string(nv, ZFS_PROP_ENCRYPTION_ROOT, buf);
        }
}

int
spa_crypt_get_salt(spa_t *spa, uint64_t dsobj, uint8_t *salt)
{
        int ret;
        dsl_crypto_key_t *dck = NULL;

        /* look up the key from the spa's keystore */
        ret = spa_keystore_lookup_key(spa, dsobj, FTAG, &dck);
        if (ret != 0)
                goto error;

        ret = zio_crypt_key_get_salt(&dck->dck_key, salt);
        if (ret != 0)
                goto error;

        spa_keystore_dsl_key_rele(spa, dck, FTAG);
        return (0);

error:
        if (dck != NULL)
                spa_keystore_dsl_key_rele(spa, dck, FTAG);
        return (ret);
}

/*
 * Objset blocks are a special case for MAC generation. These blocks have 2
 * 256-bit MACs which are embedded within the block itself, rather than a
 * single 128 bit MAC. As a result, this function handles encoding and decoding
 * the MACs on its own, unlike other functions in this file.
 */
int
spa_do_crypt_objset_mac_abd(boolean_t generate, spa_t *spa, uint64_t dsobj,
    abd_t *abd, uint_t datalen, boolean_t byteswap)
{
        int ret;
        dsl_crypto_key_t *dck = NULL;
        void *buf = abd_borrow_buf_copy(abd, datalen);
        objset_phys_t *osp = buf;
        uint8_t portable_mac[ZIO_OBJSET_MAC_LEN];
        uint8_t local_mac[ZIO_OBJSET_MAC_LEN];

        /* look up the key from the spa's keystore */
        ret = spa_keystore_lookup_key(spa, dsobj, FTAG, &dck);
        if (ret != 0)
                goto error;

        /* calculate both HMACs */
        ret = zio_crypt_do_objset_hmacs(&dck->dck_key, buf, datalen,
            byteswap, portable_mac, local_mac);
        if (ret != 0)
                goto error;

        spa_keystore_dsl_key_rele(spa, dck, FTAG);

        /* if we are generating encode the HMACs in the objset_phys_t */
        if (generate) {
                bcopy(portable_mac, osp->os_portable_mac, ZIO_OBJSET_MAC_LEN);
                bcopy(local_mac, osp->os_local_mac, ZIO_OBJSET_MAC_LEN);
                abd_return_buf_copy(abd, buf, datalen);
                return (0);
        }

        if (bcmp(portable_mac, osp->os_portable_mac, ZIO_OBJSET_MAC_LEN) != 0 ||
            bcmp(local_mac, osp->os_local_mac, ZIO_OBJSET_MAC_LEN) != 0) {
                abd_return_buf(abd, buf, datalen);
                return (SET_ERROR(ECKSUM));
        }

        abd_return_buf(abd, buf, datalen);

        return (0);

error:
        if (dck != NULL)
                spa_keystore_dsl_key_rele(spa, dck, FTAG);
        abd_return_buf(abd, buf, datalen);
        return (ret);
}

int
spa_do_crypt_mac_abd(boolean_t generate, spa_t *spa, uint64_t dsobj, abd_t *abd,
    uint_t datalen, uint8_t *mac)
{
        int ret;
        dsl_crypto_key_t *dck = NULL;
        uint8_t *buf = abd_borrow_buf_copy(abd, datalen);
        uint8_t digestbuf[ZIO_DATA_MAC_LEN];

        /* look up the key from the spa's keystore */
        ret = spa_keystore_lookup_key(spa, dsobj, FTAG, &dck);
        if (ret != 0)
                goto error;

        /* perform the hmac */
        ret = zio_crypt_do_hmac(&dck->dck_key, buf, datalen,
            digestbuf, ZIO_DATA_MAC_LEN);
        if (ret != 0)
                goto error;

        abd_return_buf(abd, buf, datalen);
        spa_keystore_dsl_key_rele(spa, dck, FTAG);

        /*
         * Truncate and fill in mac buffer if we were asked to generate a MAC.
         * Otherwise verify that the MAC matched what we expected.
         */
        if (generate) {
                bcopy(digestbuf, mac, ZIO_DATA_MAC_LEN);
                return (0);
        }

        if (bcmp(digestbuf, mac, ZIO_DATA_MAC_LEN) != 0)
                return (SET_ERROR(ECKSUM));

        return (0);

error:
        if (dck != NULL)
                spa_keystore_dsl_key_rele(spa, dck, FTAG);
        abd_return_buf(abd, buf, datalen);
        return (ret);
}

/*
 * This function serves as a multiplexer for encryption and decryption of
 * all blocks (except the L2ARC). For encryption, it will populate the IV,
 * salt, MAC, and cabd (the ciphertext). On decryption it will simply use
 * these fields to populate pabd (the plaintext).
 */
int
spa_do_crypt_abd(boolean_t encrypt, spa_t *spa, uint64_t dsobj,
    const blkptr_t *bp, uint64_t txgid, uint_t datalen, abd_t *pabd,
    abd_t *cabd, uint8_t *iv, uint8_t *mac, uint8_t *salt, boolean_t *no_crypt)
{
        int ret;
        dmu_object_type_t ot = BP_GET_TYPE(bp);
        dsl_crypto_key_t *dck = NULL;
        uint8_t *plainbuf = NULL, *cipherbuf = NULL;

        ASSERT(spa_feature_is_active(spa, SPA_FEATURE_ENCRYPTION));
        ASSERT(!BP_IS_EMBEDDED(bp));
        ASSERT(BP_IS_ENCRYPTED(bp));

        /* look up the key from the spa's keystore */
        ret = spa_keystore_lookup_key(spa, dsobj, FTAG, &dck);
        if (ret != 0)
                return (ret);

        if (encrypt) {
                plainbuf = abd_borrow_buf_copy(pabd, datalen);
                cipherbuf = abd_borrow_buf(cabd, datalen);
        } else {
                plainbuf = abd_borrow_buf(pabd, datalen);
                cipherbuf = abd_borrow_buf_copy(cabd, datalen);
        }

        /*
         * Both encryption and decryption functions need a salt for key
         * generation and an IV. When encrypting a non-dedup block, we
         * generate the salt and IV randomly to be stored by the caller. Dedup
         * blocks perform a (more expensive) HMAC of the plaintext to obtain
         * the salt and the IV. ZIL blocks have their salt and IV generated
         * at allocation time in zio_alloc_zil(). On decryption, we simply use
         * the provided values.
         */
        if (encrypt && ot != DMU_OT_INTENT_LOG && !BP_GET_DEDUP(bp)) {
                ret = zio_crypt_key_get_salt(&dck->dck_key, salt);
                if (ret != 0)
                        goto error;

                ret = zio_crypt_generate_iv(iv);
                if (ret != 0)
                        goto error;
        } else if (encrypt && BP_GET_DEDUP(bp)) {
                ret = zio_crypt_generate_iv_salt_dedup(&dck->dck_key,
                    plainbuf, datalen, iv, salt);
                if (ret != 0)
                        goto error;
        }

        /* call lower level function to perform encryption / decryption */
        ret = zio_do_crypt_data(encrypt, &dck->dck_key, salt, ot, iv, mac,
            datalen, BP_SHOULD_BYTESWAP(bp), plainbuf, cipherbuf, no_crypt);
        if (ret != 0)
                goto error;

        if (encrypt) {
                abd_return_buf(pabd, plainbuf, datalen);
                abd_return_buf_copy(cabd, cipherbuf, datalen);
        } else {
                abd_return_buf_copy(pabd, plainbuf, datalen);
                abd_return_buf(cabd, cipherbuf, datalen);
        }

        spa_keystore_dsl_key_rele(spa, dck, FTAG);

        return (0);

error:
        if (encrypt) {
                /* zero out any state we might have changed while encrypting */
                bzero(salt, ZIO_DATA_SALT_LEN);
                bzero(iv, ZIO_DATA_IV_LEN);
                bzero(mac, ZIO_DATA_MAC_LEN);
                abd_return_buf(pabd, plainbuf, datalen);
                abd_return_buf_copy(cabd, cipherbuf, datalen);
        } else {
                abd_return_buf_copy(pabd, plainbuf, datalen);
                abd_return_buf(cabd, cipherbuf, datalen);
        }

        spa_keystore_dsl_key_rele(spa, dck, FTAG);

        return (ret);
}