FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/os/linux/zfs/zio_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/zio_crypt.h>
    #include <sys/dmu.h>
    #include <sys/dmu_objset.h>
    #include <sys/dnode.h>
    #include <sys/fs/zfs.h>
    #include <sys/zio.h>
    #include <sys/zil.h>
    #include <sys/sha2.h>
    #include <sys/hkdf.h>
    #include <sys/qat.h>
    
    /*
     * This file is responsible for handling all of the details of generating
     * encryption parameters and performing encryption and authentication.
     *
     * BLOCK ENCRYPTION PARAMETERS:
     * Encryption /Authentication Algorithm Suite (crypt):
     * The encryption algorithm, mode, and key length we are going to use. We
     * currently support AES in either GCM or CCM modes with 128, 192, and 256 bit
     * keys. All authentication is currently done with SHA512-HMAC.
     *
     * Plaintext:
     * The unencrypted data that we want to encrypt.
     *
     * Initialization Vector (IV):
     * An initialization vector for the encryption algorithms. This is used to
     * "tweak" the encryption algorithms so that two blocks of the same data are
     * encrypted into different ciphertext outputs, thus obfuscating block patterns.
     * The supported encryption modes (AES-GCM and AES-CCM) require that an IV is
     * never reused with the same encryption key. This value is stored unencrypted
     * and must simply be provided to the decryption function. We use a 96 bit IV
     * (as recommended by NIST) for all block encryption. For non-dedup blocks we
     * derive the IV randomly. The first 64 bits of the IV are stored in the second
     * word of DVA[2] and the remaining 32 bits are stored in the upper 32 bits of
     * blk_fill. This is safe because encrypted blocks can't use the upper 32 bits
     * of blk_fill. We only encrypt level 0 blocks, which normally have a fill count
     * of 1. The only exception is for DMU_OT_DNODE objects, where the fill count of
     * level 0 blocks is the number of allocated dnodes in that block. The on-disk
     * format supports at most 2^15 slots per L0 dnode block, because the maximum
     * block size is 16MB (2^24). In either case, for level 0 blocks this number
     * will still be smaller than UINT32_MAX so it is safe to store the IV in the
     * top 32 bits of blk_fill, while leaving the bottom 32 bits of the fill count
     * for the dnode code.
     *
     * Master key:
     * This is the most important secret data of an encrypted dataset. It is used
     * along with the salt to generate that actual encryption keys via HKDF. We
     * do not use the master key to directly encrypt any data because there are
     * theoretical limits on how much data can actually be safely encrypted with
     * any encryption mode. The master key is stored encrypted on disk with the
     * user's wrapping key. Its length is determined by the encryption algorithm.
     * For details on how this is stored see the block comment in dsl_crypt.c
     *
     * Salt:
     * Used as an input to the HKDF function, along with the master key. We use a
     * 64 bit salt, stored unencrypted in the first word of DVA[2]. Any given salt
     * can be used for encrypting many blocks, so we cache the current salt and the
     * associated derived key in zio_crypt_t so we do not need to derive it again
     * needlessly.
     *
     * Encryption Key:
     * A secret binary key, generated from an HKDF function used to encrypt and
     * decrypt data.
     *
     * Message Authentication Code (MAC)
     * The MAC is an output of authenticated encryption modes such as AES-GCM and
     * AES-CCM. Its purpose is to ensure that an attacker cannot modify encrypted
     * data on disk and return garbage to the application. Effectively, it is a
     * checksum that can not be reproduced by an attacker. We store the MAC in the
     * second 128 bits of blk_cksum, leaving the first 128 bits for a truncated
     * regular checksum of the ciphertext which can be used for scrubbing.
     *
     * OBJECT AUTHENTICATION:
     * Some object types, such as DMU_OT_MASTER_NODE cannot be encrypted because
     * they contain some info that always needs to be readable. To prevent this
     * data from being altered, we authenticate this data using SHA512-HMAC. This
     * will produce a MAC (similar to the one produced via encryption) which can
     * be used to verify the object was not modified. HMACs do not require key
     * rotation or IVs, so we can keep up to the full 3 copies of authenticated
     * data.
    *
    * ZIL ENCRYPTION:
    * ZIL blocks have their bp written to disk ahead of the associated data, so we
    * cannot store the MAC there as we normally do. For these blocks the MAC is
    * stored in the embedded checksum within the zil_chain_t header. The salt and
    * IV are generated for the block on bp allocation instead of at encryption
    * time. In addition, ZIL blocks have some pieces that must be left in plaintext
    * for claiming even though all of the sensitive user data still needs to be
    * encrypted. The function zio_crypt_init_uios_zil() handles parsing which
    * pieces of the block need to be encrypted. All data that is not encrypted is
    * authenticated using the AAD mechanisms that the supported encryption modes
    * provide for. In order to preserve the semantics of the ZIL for encrypted
    * datasets, the ZIL is not protected at the objset level as described below.
    *
    * DNODE ENCRYPTION:
    * Similarly to ZIL blocks, the core part of each dnode_phys_t needs to be left
    * in plaintext for scrubbing and claiming, but the bonus buffers might contain
    * sensitive user data. The function zio_crypt_init_uios_dnode() handles parsing
    * which pieces of the block need to be encrypted. For more details about
    * dnode authentication and encryption, see zio_crypt_init_uios_dnode().
    *
    * OBJECT SET AUTHENTICATION:
    * Up to this point, everything we have encrypted and authenticated has been
    * at level 0 (or -2 for the ZIL). If we did not do any further work the
    * on-disk format would be susceptible to attacks that deleted or rearranged
    * the order of level 0 blocks. Ideally, the cleanest solution would be to
    * maintain a tree of authentication MACs going up the bp tree. However, this
    * presents a problem for raw sends. Send files do not send information about
    * indirect blocks so there would be no convenient way to transfer the MACs and
    * they cannot be recalculated on the receive side without the master key which
    * would defeat one of the purposes of raw sends in the first place. Instead,
    * for the indirect levels of the bp tree, we use a regular SHA512 of the MACs
    * from the level below. We also include some portable fields from blk_prop such
    * as the lsize and compression algorithm to prevent the data from being
    * misinterpreted.
    *
    * At the objset level, we maintain 2 separate 256 bit MACs in the
    * objset_phys_t. The first one is "portable" and is the logical root of the
    * MAC tree maintained in the metadnode's bps. The second, is "local" and is
    * used as the root MAC for the user accounting objects, which are also not
    * transferred via "zfs send". The portable MAC is sent in the DRR_BEGIN payload
    * of the send file. The useraccounting code ensures that the useraccounting
    * info is not present upon a receive, so the local MAC can simply be cleared
    * out at that time. For more info about objset_phys_t authentication, see
    * zio_crypt_do_objset_hmacs().
    *
    * CONSIDERATIONS FOR DEDUP:
    * In order for dedup to work, blocks that we want to dedup with one another
    * need to use the same IV and encryption key, so that they will have the same
    * ciphertext. Normally, one should never reuse an IV with the same encryption
    * key or else AES-GCM and AES-CCM can both actually leak the plaintext of both
    * blocks. In this case, however, since we are using the same plaintext as
    * well all that we end up with is a duplicate of the original ciphertext we
    * already had. As a result, an attacker with read access to the raw disk will
    * be able to tell which blocks are the same but this information is given away
    * by dedup anyway. In order to get the same IVs and encryption keys for
    * equivalent blocks of data we use an HMAC of the plaintext. We use an HMAC
    * here so that a reproducible checksum of the plaintext is never available to
    * the attacker. The HMAC key is kept alongside the master key, encrypted on
    * disk. The first 64 bits of the HMAC are used in place of the random salt, and
    * the next 96 bits are used as the IV. As a result of this mechanism, dedup
    * will only work within a clone family since encrypted dedup requires use of
    * the same master and HMAC keys.
    */
   
   /*
    * After encrypting many blocks with the same key we may start to run up
    * against the theoretical limits of how much data can securely be encrypted
    * with a single key using the supported encryption modes. The most obvious
    * limitation is that our risk of generating 2 equivalent 96 bit IVs increases
    * the more IVs we generate (which both GCM and CCM modes strictly forbid).
    * This risk actually grows surprisingly quickly over time according to the
    * Birthday Problem. With a total IV space of 2^(96 bits), and assuming we have
    * generated n IVs with a cryptographically secure RNG, the approximate
    * probability p(n) of a collision is given as:
    *
    * p(n) ~= e^(-n*(n-1)/(2*(2^96)))
    *
    * [http://www.math.cornell.edu/~mec/2008-2009/TianyiZheng/Birthday.html]
    *
    * Assuming that we want to ensure that p(n) never goes over 1 / 1 trillion
    * we must not write more than 398,065,730 blocks with the same encryption key.
    * Therefore, we rotate our keys after 400,000,000 blocks have been written by
    * generating a new random 64 bit salt for our HKDF encryption key generation
    * function.
    */
   #define ZFS_KEY_MAX_SALT_USES_DEFAULT   400000000
   #define ZFS_CURRENT_MAX_SALT_USES       \
           (MIN(zfs_key_max_salt_uses, ZFS_KEY_MAX_SALT_USES_DEFAULT))
   static unsigned long zfs_key_max_salt_uses = ZFS_KEY_MAX_SALT_USES_DEFAULT;
   
   typedef struct blkptr_auth_buf {
           uint64_t bab_prop;                      /* blk_prop - portable mask */
           uint8_t bab_mac[ZIO_DATA_MAC_LEN];      /* MAC from blk_cksum */
           uint64_t bab_pad;                       /* reserved for future use */
   } blkptr_auth_buf_t;
   
   const zio_crypt_info_t zio_crypt_table[ZIO_CRYPT_FUNCTIONS] = {
           {"",                    ZC_TYPE_NONE,   0,      "inherit"},
           {"",                    ZC_TYPE_NONE,   0,      "on"},
           {"",                    ZC_TYPE_NONE,   0,      "off"},
           {SUN_CKM_AES_CCM,       ZC_TYPE_CCM,    16,     "aes-128-ccm"},
           {SUN_CKM_AES_CCM,       ZC_TYPE_CCM,    24,     "aes-192-ccm"},
           {SUN_CKM_AES_CCM,       ZC_TYPE_CCM,    32,     "aes-256-ccm"},
           {SUN_CKM_AES_GCM,       ZC_TYPE_GCM,    16,     "aes-128-gcm"},
           {SUN_CKM_AES_GCM,       ZC_TYPE_GCM,    24,     "aes-192-gcm"},
           {SUN_CKM_AES_GCM,       ZC_TYPE_GCM,    32,     "aes-256-gcm"}
   };
   
   void
   zio_crypt_key_destroy(zio_crypt_key_t *key)
   {
           rw_destroy(&key->zk_salt_lock);
   
           /* free crypto templates */
           crypto_destroy_ctx_template(key->zk_current_tmpl);
           crypto_destroy_ctx_template(key->zk_hmac_tmpl);
   
           /* zero out sensitive data */
           memset(key, 0, sizeof (zio_crypt_key_t));
   }
   
   int
   zio_crypt_key_init(uint64_t crypt, zio_crypt_key_t *key)
   {
           int ret;
           crypto_mechanism_t mech;
           uint_t keydata_len;
   
           ASSERT(key != NULL);
           ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
   
   /*
    * Workaround for GCC 12+ with UBSan enabled deficencies.
    *
    * GCC 12+ invoked with -fsanitize=undefined incorrectly reports the code
    * below as violating -Warray-bounds
    */
   #if defined(__GNUC__) && !defined(__clang__) && \
           ((!defined(_KERNEL) && defined(ZFS_UBSAN_ENABLED)) || \
               defined(CONFIG_UBSAN))
   #pragma GCC diagnostic push
   #pragma GCC diagnostic ignored "-Warray-bounds"
   #endif
           keydata_len = zio_crypt_table[crypt].ci_keylen;
   #if defined(__GNUC__) && !defined(__clang__) && \
           ((!defined(_KERNEL) && defined(ZFS_UBSAN_ENABLED)) || \
               defined(CONFIG_UBSAN))
   #pragma GCC diagnostic pop
   #endif
           memset(key, 0, sizeof (zio_crypt_key_t));
           rw_init(&key->zk_salt_lock, NULL, RW_DEFAULT, NULL);
   
           /* fill keydata buffers and salt with random data */
           ret = random_get_bytes((uint8_t *)&key->zk_guid, sizeof (uint64_t));
           if (ret != 0)
                   goto error;
   
           ret = random_get_bytes(key->zk_master_keydata, keydata_len);
           if (ret != 0)
                   goto error;
   
           ret = random_get_bytes(key->zk_hmac_keydata, SHA512_HMAC_KEYLEN);
           if (ret != 0)
                   goto error;
   
           ret = random_get_bytes(key->zk_salt, ZIO_DATA_SALT_LEN);
           if (ret != 0)
                   goto error;
   
           /* derive the current key from the master key */
           ret = hkdf_sha512(key->zk_master_keydata, keydata_len, NULL, 0,
               key->zk_salt, ZIO_DATA_SALT_LEN, key->zk_current_keydata,
               keydata_len);
           if (ret != 0)
                   goto error;
   
           /* initialize keys for the ICP */
           key->zk_current_key.ck_data = key->zk_current_keydata;
           key->zk_current_key.ck_length = CRYPTO_BYTES2BITS(keydata_len);
   
           key->zk_hmac_key.ck_data = &key->zk_hmac_key;
           key->zk_hmac_key.ck_length = CRYPTO_BYTES2BITS(SHA512_HMAC_KEYLEN);
   
           /*
            * Initialize the crypto templates. It's ok if this fails because
            * this is just an optimization.
            */
           mech.cm_type = crypto_mech2id(zio_crypt_table[crypt].ci_mechname);
           ret = crypto_create_ctx_template(&mech, &key->zk_current_key,
               &key->zk_current_tmpl);
           if (ret != CRYPTO_SUCCESS)
                   key->zk_current_tmpl = NULL;
   
           mech.cm_type = crypto_mech2id(SUN_CKM_SHA512_HMAC);
           ret = crypto_create_ctx_template(&mech, &key->zk_hmac_key,
               &key->zk_hmac_tmpl);
           if (ret != CRYPTO_SUCCESS)
                   key->zk_hmac_tmpl = NULL;
   
           key->zk_crypt = crypt;
           key->zk_version = ZIO_CRYPT_KEY_CURRENT_VERSION;
           key->zk_salt_count = 0;
   
           return (0);
   
   error:
           zio_crypt_key_destroy(key);
           return (ret);
   }
   
   static int
   zio_crypt_key_change_salt(zio_crypt_key_t *key)
   {
           int ret = 0;
           uint8_t salt[ZIO_DATA_SALT_LEN];
           crypto_mechanism_t mech;
           uint_t keydata_len = zio_crypt_table[key->zk_crypt].ci_keylen;
   
           /* generate a new salt */
           ret = random_get_bytes(salt, ZIO_DATA_SALT_LEN);
           if (ret != 0)
                   goto error;
   
           rw_enter(&key->zk_salt_lock, RW_WRITER);
   
           /* someone beat us to the salt rotation, just unlock and return */
           if (key->zk_salt_count < ZFS_CURRENT_MAX_SALT_USES)
                   goto out_unlock;
   
           /* derive the current key from the master key and the new salt */
           ret = hkdf_sha512(key->zk_master_keydata, keydata_len, NULL, 0,
               salt, ZIO_DATA_SALT_LEN, key->zk_current_keydata, keydata_len);
           if (ret != 0)
                   goto out_unlock;
   
           /* assign the salt and reset the usage count */
           memcpy(key->zk_salt, salt, ZIO_DATA_SALT_LEN);
           key->zk_salt_count = 0;
   
           /* destroy the old context template and create the new one */
           crypto_destroy_ctx_template(key->zk_current_tmpl);
           ret = crypto_create_ctx_template(&mech, &key->zk_current_key,
               &key->zk_current_tmpl);
           if (ret != CRYPTO_SUCCESS)
                   key->zk_current_tmpl = NULL;
   
           rw_exit(&key->zk_salt_lock);
   
           return (0);
   
   out_unlock:
           rw_exit(&key->zk_salt_lock);
   error:
           return (ret);
   }
   
   /* See comment above zfs_key_max_salt_uses definition for details */
   int
   zio_crypt_key_get_salt(zio_crypt_key_t *key, uint8_t *salt)
   {
           int ret;
           boolean_t salt_change;
   
           rw_enter(&key->zk_salt_lock, RW_READER);
   
           memcpy(salt, key->zk_salt, ZIO_DATA_SALT_LEN);
           salt_change = (atomic_inc_64_nv(&key->zk_salt_count) >=
               ZFS_CURRENT_MAX_SALT_USES);
   
           rw_exit(&key->zk_salt_lock);
   
           if (salt_change) {
                   ret = zio_crypt_key_change_salt(key);
                   if (ret != 0)
                           goto error;
           }
   
           return (0);
   
   error:
           return (ret);
   }
   
   /*
    * This function handles all encryption and decryption in zfs. When
    * encrypting it expects puio to reference the plaintext and cuio to
    * reference the ciphertext. cuio must have enough space for the
    * ciphertext + room for a MAC. datalen should be the length of the
    * plaintext / ciphertext alone.
    */
   static int
   zio_do_crypt_uio(boolean_t encrypt, uint64_t crypt, crypto_key_t *key,
       crypto_ctx_template_t tmpl, uint8_t *ivbuf, uint_t datalen,
       zfs_uio_t *puio, zfs_uio_t *cuio, uint8_t *authbuf, uint_t auth_len)
   {
           int ret;
           crypto_data_t plaindata, cipherdata;
           CK_AES_CCM_PARAMS ccmp;
           CK_AES_GCM_PARAMS gcmp;
           crypto_mechanism_t mech;
           zio_crypt_info_t crypt_info;
           uint_t plain_full_len, maclen;
   
           ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
   
           /* lookup the encryption info */
           crypt_info = zio_crypt_table[crypt];
   
           /* the mac will always be the last iovec_t in the cipher uio */
           maclen = cuio->uio_iov[cuio->uio_iovcnt - 1].iov_len;
   
           ASSERT(maclen <= ZIO_DATA_MAC_LEN);
   
           /* setup encryption mechanism (same as crypt) */
           mech.cm_type = crypto_mech2id(crypt_info.ci_mechname);
   
           /*
            * Strangely, the ICP requires that plain_full_len must include
            * the MAC length when decrypting, even though the UIO does not
            * need to have the extra space allocated.
            */
           if (encrypt) {
                   plain_full_len = datalen;
           } else {
                   plain_full_len = datalen + maclen;
           }
   
           /*
            * setup encryption params (currently only AES CCM and AES GCM
            * are supported)
            */
           if (crypt_info.ci_crypt_type == ZC_TYPE_CCM) {
                   ccmp.ulNonceSize = ZIO_DATA_IV_LEN;
                   ccmp.ulAuthDataSize = auth_len;
                   ccmp.authData = authbuf;
                   ccmp.ulMACSize = maclen;
                   ccmp.nonce = ivbuf;
                   ccmp.ulDataSize = plain_full_len;
   
                   mech.cm_param = (char *)(&ccmp);
                   mech.cm_param_len = sizeof (CK_AES_CCM_PARAMS);
           } else {
                   gcmp.ulIvLen = ZIO_DATA_IV_LEN;
                   gcmp.ulIvBits = CRYPTO_BYTES2BITS(ZIO_DATA_IV_LEN);
                   gcmp.ulAADLen = auth_len;
                   gcmp.pAAD = authbuf;
                   gcmp.ulTagBits = CRYPTO_BYTES2BITS(maclen);
                   gcmp.pIv = ivbuf;
   
                   mech.cm_param = (char *)(&gcmp);
                   mech.cm_param_len = sizeof (CK_AES_GCM_PARAMS);
           }
   
           /* populate the cipher and plain data structs. */
           plaindata.cd_format = CRYPTO_DATA_UIO;
           plaindata.cd_offset = 0;
           plaindata.cd_uio = puio;
           plaindata.cd_length = plain_full_len;
   
           cipherdata.cd_format = CRYPTO_DATA_UIO;
           cipherdata.cd_offset = 0;
           cipherdata.cd_uio = cuio;
           cipherdata.cd_length = datalen + maclen;
   
           /* perform the actual encryption */
           if (encrypt) {
                   ret = crypto_encrypt(&mech, &plaindata, key, tmpl, &cipherdata);
                   if (ret != CRYPTO_SUCCESS) {
                           ret = SET_ERROR(EIO);
                           goto error;
                   }
           } else {
                   ret = crypto_decrypt(&mech, &cipherdata, key, tmpl, &plaindata);
                   if (ret != CRYPTO_SUCCESS) {
                           ASSERT3U(ret, ==, CRYPTO_INVALID_MAC);
                           ret = SET_ERROR(ECKSUM);
                           goto error;
                   }
           }
   
           return (0);
   
   error:
           return (ret);
   }
   
   int
   zio_crypt_key_wrap(crypto_key_t *cwkey, zio_crypt_key_t *key, uint8_t *iv,
       uint8_t *mac, uint8_t *keydata_out, uint8_t *hmac_keydata_out)
   {
           int ret;
           zfs_uio_t puio, cuio;
           uint64_t aad[3];
           iovec_t plain_iovecs[2], cipher_iovecs[3];
           uint64_t crypt = key->zk_crypt;
           uint_t enc_len, keydata_len, aad_len;
   
           ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
   
           keydata_len = zio_crypt_table[crypt].ci_keylen;
   
           /* generate iv for wrapping the master and hmac key */
           ret = random_get_pseudo_bytes(iv, WRAPPING_IV_LEN);
           if (ret != 0)
                   goto error;
   
           /* initialize zfs_uio_ts */
           plain_iovecs[0].iov_base = key->zk_master_keydata;
           plain_iovecs[0].iov_len = keydata_len;
           plain_iovecs[1].iov_base = key->zk_hmac_keydata;
           plain_iovecs[1].iov_len = SHA512_HMAC_KEYLEN;
   
           cipher_iovecs[0].iov_base = keydata_out;
           cipher_iovecs[0].iov_len = keydata_len;
           cipher_iovecs[1].iov_base = hmac_keydata_out;
           cipher_iovecs[1].iov_len = SHA512_HMAC_KEYLEN;
           cipher_iovecs[2].iov_base = mac;
           cipher_iovecs[2].iov_len = WRAPPING_MAC_LEN;
   
           /*
            * Although we don't support writing to the old format, we do
            * support rewrapping the key so that the user can move and
            * quarantine datasets on the old format.
            */
           if (key->zk_version == 0) {
                   aad_len = sizeof (uint64_t);
                   aad[0] = LE_64(key->zk_guid);
           } else {
                   ASSERT3U(key->zk_version, ==, ZIO_CRYPT_KEY_CURRENT_VERSION);
                   aad_len = sizeof (uint64_t) * 3;
                   aad[0] = LE_64(key->zk_guid);
                   aad[1] = LE_64(crypt);
                   aad[2] = LE_64(key->zk_version);
           }
   
           enc_len = zio_crypt_table[crypt].ci_keylen + SHA512_HMAC_KEYLEN;
           puio.uio_iov = plain_iovecs;
           puio.uio_iovcnt = 2;
           puio.uio_segflg = UIO_SYSSPACE;
           cuio.uio_iov = cipher_iovecs;
           cuio.uio_iovcnt = 3;
           cuio.uio_segflg = UIO_SYSSPACE;
   
           /* encrypt the keys and store the resulting ciphertext and mac */
           ret = zio_do_crypt_uio(B_TRUE, crypt, cwkey, NULL, iv, enc_len,
               &puio, &cuio, (uint8_t *)aad, aad_len);
           if (ret != 0)
                   goto error;
   
           return (0);
   
   error:
           return (ret);
   }
   
   int
   zio_crypt_key_unwrap(crypto_key_t *cwkey, uint64_t crypt, uint64_t version,
       uint64_t guid, uint8_t *keydata, uint8_t *hmac_keydata, uint8_t *iv,
       uint8_t *mac, zio_crypt_key_t *key)
   {
           crypto_mechanism_t mech;
           zfs_uio_t puio, cuio;
           uint64_t aad[3];
           iovec_t plain_iovecs[2], cipher_iovecs[3];
           uint_t enc_len, keydata_len, aad_len;
           int ret;
   
           ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
   
           rw_init(&key->zk_salt_lock, NULL, RW_DEFAULT, NULL);
   
           keydata_len = zio_crypt_table[crypt].ci_keylen;
   
           /* initialize zfs_uio_ts */
           plain_iovecs[0].iov_base = key->zk_master_keydata;
           plain_iovecs[0].iov_len = keydata_len;
           plain_iovecs[1].iov_base = key->zk_hmac_keydata;
           plain_iovecs[1].iov_len = SHA512_HMAC_KEYLEN;
   
           cipher_iovecs[0].iov_base = keydata;
           cipher_iovecs[0].iov_len = keydata_len;
           cipher_iovecs[1].iov_base = hmac_keydata;
           cipher_iovecs[1].iov_len = SHA512_HMAC_KEYLEN;
           cipher_iovecs[2].iov_base = mac;
           cipher_iovecs[2].iov_len = WRAPPING_MAC_LEN;
   
           if (version == 0) {
                   aad_len = sizeof (uint64_t);
                   aad[0] = LE_64(guid);
           } else {
                   ASSERT3U(version, ==, ZIO_CRYPT_KEY_CURRENT_VERSION);
                   aad_len = sizeof (uint64_t) * 3;
                   aad[0] = LE_64(guid);
                   aad[1] = LE_64(crypt);
                   aad[2] = LE_64(version);
           }
   
           enc_len = keydata_len + SHA512_HMAC_KEYLEN;
           puio.uio_iov = plain_iovecs;
           puio.uio_segflg = UIO_SYSSPACE;
           puio.uio_iovcnt = 2;
           cuio.uio_iov = cipher_iovecs;
           cuio.uio_iovcnt = 3;
           cuio.uio_segflg = UIO_SYSSPACE;
   
           /* decrypt the keys and store the result in the output buffers */
           ret = zio_do_crypt_uio(B_FALSE, crypt, cwkey, NULL, iv, enc_len,
               &puio, &cuio, (uint8_t *)aad, aad_len);
           if (ret != 0)
                   goto error;
   
           /* generate a fresh salt */
           ret = random_get_bytes(key->zk_salt, ZIO_DATA_SALT_LEN);
           if (ret != 0)
                   goto error;
   
           /* derive the current key from the master key */
           ret = hkdf_sha512(key->zk_master_keydata, keydata_len, NULL, 0,
               key->zk_salt, ZIO_DATA_SALT_LEN, key->zk_current_keydata,
               keydata_len);
           if (ret != 0)
                   goto error;
   
           /* initialize keys for ICP */
           key->zk_current_key.ck_data = key->zk_current_keydata;
           key->zk_current_key.ck_length = CRYPTO_BYTES2BITS(keydata_len);
   
           key->zk_hmac_key.ck_data = key->zk_hmac_keydata;
           key->zk_hmac_key.ck_length = CRYPTO_BYTES2BITS(SHA512_HMAC_KEYLEN);
   
           /*
            * Initialize the crypto templates. It's ok if this fails because
            * this is just an optimization.
            */
           mech.cm_type = crypto_mech2id(zio_crypt_table[crypt].ci_mechname);
           ret = crypto_create_ctx_template(&mech, &key->zk_current_key,
               &key->zk_current_tmpl);
           if (ret != CRYPTO_SUCCESS)
                   key->zk_current_tmpl = NULL;
   
           mech.cm_type = crypto_mech2id(SUN_CKM_SHA512_HMAC);
           ret = crypto_create_ctx_template(&mech, &key->zk_hmac_key,
               &key->zk_hmac_tmpl);
           if (ret != CRYPTO_SUCCESS)
                   key->zk_hmac_tmpl = NULL;
   
           key->zk_crypt = crypt;
           key->zk_version = version;
           key->zk_guid = guid;
           key->zk_salt_count = 0;
   
           return (0);
   
   error:
           zio_crypt_key_destroy(key);
           return (ret);
   }
   
   int
   zio_crypt_generate_iv(uint8_t *ivbuf)
   {
           int ret;
   
           /* randomly generate the IV */
           ret = random_get_pseudo_bytes(ivbuf, ZIO_DATA_IV_LEN);
           if (ret != 0)
                   goto error;
   
           return (0);
   
   error:
           memset(ivbuf, 0, ZIO_DATA_IV_LEN);
           return (ret);
   }
   
   int
   zio_crypt_do_hmac(zio_crypt_key_t *key, uint8_t *data, uint_t datalen,
       uint8_t *digestbuf, uint_t digestlen)
   {
           int ret;
           crypto_mechanism_t mech;
           crypto_data_t in_data, digest_data;
           uint8_t raw_digestbuf[SHA512_DIGEST_LENGTH];
   
           ASSERT3U(digestlen, <=, SHA512_DIGEST_LENGTH);
   
           /* initialize sha512-hmac mechanism and crypto data */
           mech.cm_type = crypto_mech2id(SUN_CKM_SHA512_HMAC);
           mech.cm_param = NULL;
           mech.cm_param_len = 0;
   
           /* initialize the crypto data */
           in_data.cd_format = CRYPTO_DATA_RAW;
           in_data.cd_offset = 0;
           in_data.cd_length = datalen;
           in_data.cd_raw.iov_base = (char *)data;
           in_data.cd_raw.iov_len = in_data.cd_length;
   
           digest_data.cd_format = CRYPTO_DATA_RAW;
           digest_data.cd_offset = 0;
           digest_data.cd_length = SHA512_DIGEST_LENGTH;
           digest_data.cd_raw.iov_base = (char *)raw_digestbuf;
           digest_data.cd_raw.iov_len = digest_data.cd_length;
   
           /* generate the hmac */
           ret = crypto_mac(&mech, &in_data, &key->zk_hmac_key, key->zk_hmac_tmpl,
               &digest_data);
           if (ret != CRYPTO_SUCCESS) {
                   ret = SET_ERROR(EIO);
                   goto error;
           }
   
           memcpy(digestbuf, raw_digestbuf, digestlen);
   
           return (0);
   
   error:
           memset(digestbuf, 0, digestlen);
           return (ret);
   }
   
   int
   zio_crypt_generate_iv_salt_dedup(zio_crypt_key_t *key, uint8_t *data,
       uint_t datalen, uint8_t *ivbuf, uint8_t *salt)
   {
           int ret;
           uint8_t digestbuf[SHA512_DIGEST_LENGTH];
   
           ret = zio_crypt_do_hmac(key, data, datalen,
               digestbuf, SHA512_DIGEST_LENGTH);
           if (ret != 0)
                   return (ret);
   
           memcpy(salt, digestbuf, ZIO_DATA_SALT_LEN);
           memcpy(ivbuf, digestbuf + ZIO_DATA_SALT_LEN, ZIO_DATA_IV_LEN);
   
           return (0);
   }
   
   /*
    * The following functions are used to encode and decode encryption parameters
    * into blkptr_t and zil_header_t. The ICP wants to use these parameters as
    * byte strings, which normally means that these strings would not need to deal
    * with byteswapping at all. However, both blkptr_t and zil_header_t may be
    * byteswapped by lower layers and so we must "undo" that byteswap here upon
    * decoding and encoding in a non-native byteorder. These functions require
    * that the byteorder bit is correct before being called.
    */
   void
   zio_crypt_encode_params_bp(blkptr_t *bp, uint8_t *salt, uint8_t *iv)
   {
           uint64_t val64;
           uint32_t val32;
   
           ASSERT(BP_IS_ENCRYPTED(bp));
   
           if (!BP_SHOULD_BYTESWAP(bp)) {
                   memcpy(&bp->blk_dva[2].dva_word[0], salt, sizeof (uint64_t));
                   memcpy(&bp->blk_dva[2].dva_word[1], iv, sizeof (uint64_t));
                   memcpy(&val32, iv + sizeof (uint64_t), sizeof (uint32_t));
                   BP_SET_IV2(bp, val32);
           } else {
                   memcpy(&val64, salt, sizeof (uint64_t));
                   bp->blk_dva[2].dva_word[0] = BSWAP_64(val64);
   
                   memcpy(&val64, iv, sizeof (uint64_t));
                   bp->blk_dva[2].dva_word[1] = BSWAP_64(val64);
   
                   memcpy(&val32, iv + sizeof (uint64_t), sizeof (uint32_t));
                   BP_SET_IV2(bp, BSWAP_32(val32));
           }
   }
   
   void
   zio_crypt_decode_params_bp(const blkptr_t *bp, uint8_t *salt, uint8_t *iv)
   {
           uint64_t val64;
           uint32_t val32;
   
           ASSERT(BP_IS_PROTECTED(bp));
   
           /* for convenience, so callers don't need to check */
           if (BP_IS_AUTHENTICATED(bp)) {
                   memset(salt, 0, ZIO_DATA_SALT_LEN);
                   memset(iv, 0, ZIO_DATA_IV_LEN);
                   return;
           }
   
           if (!BP_SHOULD_BYTESWAP(bp)) {
                   memcpy(salt, &bp->blk_dva[2].dva_word[0], sizeof (uint64_t));
                   memcpy(iv, &bp->blk_dva[2].dva_word[1], sizeof (uint64_t));
   
                   val32 = (uint32_t)BP_GET_IV2(bp);
                   memcpy(iv + sizeof (uint64_t), &val32, sizeof (uint32_t));
           } else {
                   val64 = BSWAP_64(bp->blk_dva[2].dva_word[0]);
                   memcpy(salt, &val64, sizeof (uint64_t));
   
                   val64 = BSWAP_64(bp->blk_dva[2].dva_word[1]);
                   memcpy(iv, &val64, sizeof (uint64_t));
   
                   val32 = BSWAP_32((uint32_t)BP_GET_IV2(bp));
                   memcpy(iv + sizeof (uint64_t), &val32, sizeof (uint32_t));
           }
   }
   
   void
   zio_crypt_encode_mac_bp(blkptr_t *bp, uint8_t *mac)
   {
           uint64_t val64;
   
           ASSERT(BP_USES_CRYPT(bp));
           ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_OBJSET);
   
           if (!BP_SHOULD_BYTESWAP(bp)) {
                   memcpy(&bp->blk_cksum.zc_word[2], mac, sizeof (uint64_t));
                   memcpy(&bp->blk_cksum.zc_word[3], mac + sizeof (uint64_t),
                       sizeof (uint64_t));
           } else {
                   memcpy(&val64, mac, sizeof (uint64_t));
                   bp->blk_cksum.zc_word[2] = BSWAP_64(val64);
   
                   memcpy(&val64, mac + sizeof (uint64_t), sizeof (uint64_t));
                   bp->blk_cksum.zc_word[3] = BSWAP_64(val64);
           }
   }
   
   void
   zio_crypt_decode_mac_bp(const blkptr_t *bp, uint8_t *mac)
   {
           uint64_t val64;
   
           ASSERT(BP_USES_CRYPT(bp) || BP_IS_HOLE(bp));
   
           /* for convenience, so callers don't need to check */
           if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
                   memset(mac, 0, ZIO_DATA_MAC_LEN);
                   return;
           }
   
           if (!BP_SHOULD_BYTESWAP(bp)) {
                   memcpy(mac, &bp->blk_cksum.zc_word[2], sizeof (uint64_t));
                   memcpy(mac + sizeof (uint64_t), &bp->blk_cksum.zc_word[3],
                       sizeof (uint64_t));
           } else {
                   val64 = BSWAP_64(bp->blk_cksum.zc_word[2]);
                   memcpy(mac, &val64, sizeof (uint64_t));
   
                   val64 = BSWAP_64(bp->blk_cksum.zc_word[3]);
                   memcpy(mac + sizeof (uint64_t), &val64, sizeof (uint64_t));
           }
   }
   
   void
   zio_crypt_encode_mac_zil(void *data, uint8_t *mac)
   {
           zil_chain_t *zilc = data;
   
           memcpy(&zilc->zc_eck.zec_cksum.zc_word[2], mac, sizeof (uint64_t));
           memcpy(&zilc->zc_eck.zec_cksum.zc_word[3], mac + sizeof (uint64_t),
               sizeof (uint64_t));
   }
   
   void
   zio_crypt_decode_mac_zil(const void *data, uint8_t *mac)
   {
           /*
            * The ZIL MAC is embedded in the block it protects, which will
            * not have been byteswapped by the time this function has been called.
            * As a result, we don't need to worry about byteswapping the MAC.
            */
           const zil_chain_t *zilc = data;
   
           memcpy(mac, &zilc->zc_eck.zec_cksum.zc_word[2], sizeof (uint64_t));
           memcpy(mac + sizeof (uint64_t), &zilc->zc_eck.zec_cksum.zc_word[3],
               sizeof (uint64_t));
   }
   
   /*
    * This routine takes a block of dnodes (src_abd) and copies only the bonus
    * buffers to the same offsets in the dst buffer. datalen should be the size
    * of both the src_abd and the dst buffer (not just the length of the bonus
    * buffers).
    */
   void
   zio_crypt_copy_dnode_bonus(abd_t *src_abd, uint8_t *dst, uint_t datalen)
   {
           uint_t i, max_dnp = datalen >> DNODE_SHIFT;
           uint8_t *src;
           dnode_phys_t *dnp, *sdnp, *ddnp;
   
           src = abd_borrow_buf_copy(src_abd, datalen);
   
           sdnp = (dnode_phys_t *)src;
           ddnp = (dnode_phys_t *)dst;
   
           for (i = 0; i < max_dnp; i += sdnp[i].dn_extra_slots + 1) {
                   dnp = &sdnp[i];
                   if (dnp->dn_type != DMU_OT_NONE &&
                       DMU_OT_IS_ENCRYPTED(dnp->dn_bonustype) &&
                       dnp->dn_bonuslen != 0) {
                           memcpy(DN_BONUS(&ddnp[i]), DN_BONUS(dnp),
                               DN_MAX_BONUS_LEN(dnp));
                   }
           }
   
           abd_return_buf(src_abd, src, datalen);
   }
   
   /*
    * This function decides what fields from blk_prop are included in
    * the on-disk various MAC algorithms.
    */
   static void
   zio_crypt_bp_zero_nonportable_blkprop(blkptr_t *bp, uint64_t version)
   {
           /*
            * Version 0 did not properly zero out all non-portable fields
            * as it should have done. We maintain this code so that we can
            * do read-only imports of pools on this version.
            */
           if (version == 0) {
                   BP_SET_DEDUP(bp, 0);
                   BP_SET_CHECKSUM(bp, 0);
                   BP_SET_PSIZE(bp, SPA_MINBLOCKSIZE);
                   return;
           }
   
           ASSERT3U(version, ==, ZIO_CRYPT_KEY_CURRENT_VERSION);
   
           /*
            * The hole_birth feature might set these fields even if this bp
            * is a hole. We zero them out here to guarantee that raw sends
            * will function with or without the feature.
            */
           if (BP_IS_HOLE(bp)) {
                   bp->blk_prop = 0ULL;
                   return;
           }
   
           /*
            * At L0 we want to verify these fields to ensure that data blocks
            * can not be reinterpreted. For instance, we do not want an attacker
            * to trick us into returning raw lz4 compressed data to the user
            * by modifying the compression bits. At higher levels, we cannot
            * enforce this policy since raw sends do not convey any information
            * about indirect blocks, so these values might be different on the
            * receive side. Fortunately, this does not open any new attack
            * vectors, since any alterations that can be made to a higher level
            * bp must still verify the correct order of the layer below it.
            */
           if (BP_GET_LEVEL(bp) != 0) {
                   BP_SET_BYTEORDER(bp, 0);
                   BP_SET_COMPRESS(bp, 0);
   
                   /*
                    * psize cannot be set to zero or it will trigger
                    * asserts, but the value doesn't really matter as
                    * long as it is constant.
                    */
                   BP_SET_PSIZE(bp, SPA_MINBLOCKSIZE);
           }
   
           BP_SET_DEDUP(bp, 0);
           BP_SET_CHECKSUM(bp, 0);
   }
   
   static void
   zio_crypt_bp_auth_init(uint64_t version, boolean_t should_bswap, blkptr_t *bp,
       blkptr_auth_buf_t *bab, uint_t *bab_len)
   {
           blkptr_t tmpbp = *bp;
   
           if (should_bswap)
                   byteswap_uint64_array(&tmpbp, sizeof (blkptr_t));
   
           ASSERT(BP_USES_CRYPT(&tmpbp) || BP_IS_HOLE(&tmpbp));
           ASSERT0(BP_IS_EMBEDDED(&tmpbp));
   
           zio_crypt_decode_mac_bp(&tmpbp, bab->bab_mac);
   
           /*
            * We always MAC blk_prop in LE to ensure portability. This
            * must be done after decoding the mac, since the endianness
            * will get zero'd out here.
            */
           zio_crypt_bp_zero_nonportable_blkprop(&tmpbp, version);
           bab->bab_prop = LE_64(tmpbp.blk_prop);
           bab->bab_pad = 0ULL;
   
           /* version 0 did not include the padding */
           *bab_len = sizeof (blkptr_auth_buf_t);
           if (version == 0)
                   *bab_len -= sizeof (uint64_t);
   }
   
   static int
   zio_crypt_bp_do_hmac_updates(crypto_context_t ctx, uint64_t version,
       boolean_t should_bswap, blkptr_t *bp)
  {
          int ret;
          uint_t bab_len;
          blkptr_auth_buf_t bab;
          crypto_data_t cd;
  
          zio_crypt_bp_auth_init(version, should_bswap, bp, &bab, &bab_len);
          cd.cd_format = CRYPTO_DATA_RAW;
          cd.cd_offset = 0;
          cd.cd_length = bab_len;
          cd.cd_raw.iov_base = (char *)&bab;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_update(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          return (0);
  
  error:
          return (ret);
  }
  
  static void
  zio_crypt_bp_do_indrect_checksum_updates(SHA2_CTX *ctx, uint64_t version,
      boolean_t should_bswap, blkptr_t *bp)
  {
          uint_t bab_len;
          blkptr_auth_buf_t bab;
  
          zio_crypt_bp_auth_init(version, should_bswap, bp, &bab, &bab_len);
          SHA2Update(ctx, &bab, bab_len);
  }
  
  static void
  zio_crypt_bp_do_aad_updates(uint8_t **aadp, uint_t *aad_len, uint64_t version,
      boolean_t should_bswap, blkptr_t *bp)
  {
          uint_t bab_len;
          blkptr_auth_buf_t bab;
  
          zio_crypt_bp_auth_init(version, should_bswap, bp, &bab, &bab_len);
          memcpy(*aadp, &bab, bab_len);
          *aadp += bab_len;
          *aad_len += bab_len;
  }
  
  static int
  zio_crypt_do_dnode_hmac_updates(crypto_context_t ctx, uint64_t version,
      boolean_t should_bswap, dnode_phys_t *dnp)
  {
          int ret, i;
          dnode_phys_t *adnp, tmp_dncore;
          size_t dn_core_size = offsetof(dnode_phys_t, dn_blkptr);
          boolean_t le_bswap = (should_bswap == ZFS_HOST_BYTEORDER);
          crypto_data_t cd;
  
          cd.cd_format = CRYPTO_DATA_RAW;
          cd.cd_offset = 0;
  
          /*
           * Authenticate the core dnode (masking out non-portable bits).
           * We only copy the first 64 bytes we operate on to avoid the overhead
           * of copying 512-64 unneeded bytes. The compiler seems to be fine
           * with that.
           */
          memcpy(&tmp_dncore, dnp, dn_core_size);
          adnp = &tmp_dncore;
  
          if (le_bswap) {
                  adnp->dn_datablkszsec = BSWAP_16(adnp->dn_datablkszsec);
                  adnp->dn_bonuslen = BSWAP_16(adnp->dn_bonuslen);
                  adnp->dn_maxblkid = BSWAP_64(adnp->dn_maxblkid);
                  adnp->dn_used = BSWAP_64(adnp->dn_used);
          }
          adnp->dn_flags &= DNODE_CRYPT_PORTABLE_FLAGS_MASK;
          adnp->dn_used = 0;
  
          cd.cd_length = dn_core_size;
          cd.cd_raw.iov_base = (char *)adnp;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_update(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          for (i = 0; i < dnp->dn_nblkptr; i++) {
                  ret = zio_crypt_bp_do_hmac_updates(ctx, version,
                      should_bswap, &dnp->dn_blkptr[i]);
                  if (ret != 0)
                          goto error;
          }
  
          if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
                  ret = zio_crypt_bp_do_hmac_updates(ctx, version,
                      should_bswap, DN_SPILL_BLKPTR(dnp));
                  if (ret != 0)
                          goto error;
          }
  
          return (0);
  
  error:
          return (ret);
  }
  
  /*
   * objset_phys_t blocks introduce a number of exceptions to the normal
   * authentication process. objset_phys_t's contain 2 separate HMACS for
   * protecting the integrity of their data. The portable_mac protects the
   * metadnode. This MAC can be sent with a raw send and protects against
   * reordering of data within the metadnode. The local_mac protects the user
   * accounting objects which are not sent from one system to another.
   *
   * In addition, objset blocks are the only blocks that can be modified and
   * written to disk without the key loaded under certain circumstances. During
   * zil_claim() we need to be able to update the zil_header_t to complete
   * claiming log blocks and during raw receives we need to write out the
   * portable_mac from the send file. Both of these actions are possible
   * because these fields are not protected by either MAC so neither one will
   * need to modify the MACs without the key. However, when the modified blocks
   * are written out they will be byteswapped into the host machine's native
   * endianness which will modify fields protected by the MAC. As a result, MAC
   * calculation for objset blocks works slightly differently from other block
   * types. Where other block types MAC the data in whatever endianness is
   * written to disk, objset blocks always MAC little endian version of their
   * values. In the code, should_bswap is the value from BP_SHOULD_BYTESWAP()
   * and le_bswap indicates whether a byteswap is needed to get this block
   * into little endian format.
   */
  int
  zio_crypt_do_objset_hmacs(zio_crypt_key_t *key, void *data, uint_t datalen,
      boolean_t should_bswap, uint8_t *portable_mac, uint8_t *local_mac)
  {
          int ret;
          crypto_mechanism_t mech;
          crypto_context_t ctx;
          crypto_data_t cd;
          objset_phys_t *osp = data;
          uint64_t intval;
          boolean_t le_bswap = (should_bswap == ZFS_HOST_BYTEORDER);
          uint8_t raw_portable_mac[SHA512_DIGEST_LENGTH];
          uint8_t raw_local_mac[SHA512_DIGEST_LENGTH];
  
          /* initialize HMAC mechanism */
          mech.cm_type = crypto_mech2id(SUN_CKM_SHA512_HMAC);
          mech.cm_param = NULL;
          mech.cm_param_len = 0;
  
          cd.cd_format = CRYPTO_DATA_RAW;
          cd.cd_offset = 0;
  
          /* calculate the portable MAC from the portable fields and metadnode */
          ret = crypto_mac_init(&mech, &key->zk_hmac_key, NULL, &ctx);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          /* add in the os_type */
          intval = (le_bswap) ? osp->os_type : BSWAP_64(osp->os_type);
          cd.cd_length = sizeof (uint64_t);
          cd.cd_raw.iov_base = (char *)&intval;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_update(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          /* add in the portable os_flags */
          intval = osp->os_flags;
          if (should_bswap)
                  intval = BSWAP_64(intval);
          intval &= OBJSET_CRYPT_PORTABLE_FLAGS_MASK;
          if (!ZFS_HOST_BYTEORDER)
                  intval = BSWAP_64(intval);
  
          cd.cd_length = sizeof (uint64_t);
          cd.cd_raw.iov_base = (char *)&intval;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_update(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          /* add in fields from the metadnode */
          ret = zio_crypt_do_dnode_hmac_updates(ctx, key->zk_version,
              should_bswap, &osp->os_meta_dnode);
          if (ret)
                  goto error;
  
          /* store the final digest in a temporary buffer and copy what we need */
          cd.cd_length = SHA512_DIGEST_LENGTH;
          cd.cd_raw.iov_base = (char *)raw_portable_mac;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_final(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          memcpy(portable_mac, raw_portable_mac, ZIO_OBJSET_MAC_LEN);
  
          /*
           * This is necessary here as we check next whether
           * OBJSET_FLAG_USERACCOUNTING_COMPLETE is set in order to
           * decide if the local_mac should be zeroed out. That flag will always
           * be set by dmu_objset_id_quota_upgrade_cb() and
           * dmu_objset_userspace_upgrade_cb() if useraccounting has been
           * completed.
           */
          intval = osp->os_flags;
          if (should_bswap)
                  intval = BSWAP_64(intval);
          boolean_t uacct_incomplete =
              !(intval & OBJSET_FLAG_USERACCOUNTING_COMPLETE);
  
          /*
           * The local MAC protects the user, group and project accounting.
           * If these objects are not present, the local MAC is zeroed out.
           */
          if (uacct_incomplete ||
              (datalen >= OBJSET_PHYS_SIZE_V3 &&
              osp->os_userused_dnode.dn_type == DMU_OT_NONE &&
              osp->os_groupused_dnode.dn_type == DMU_OT_NONE &&
              osp->os_projectused_dnode.dn_type == DMU_OT_NONE) ||
              (datalen >= OBJSET_PHYS_SIZE_V2 &&
              osp->os_userused_dnode.dn_type == DMU_OT_NONE &&
              osp->os_groupused_dnode.dn_type == DMU_OT_NONE) ||
              (datalen <= OBJSET_PHYS_SIZE_V1)) {
                  memset(local_mac, 0, ZIO_OBJSET_MAC_LEN);
                  return (0);
          }
  
          /* calculate the local MAC from the userused and groupused dnodes */
          ret = crypto_mac_init(&mech, &key->zk_hmac_key, NULL, &ctx);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          /* add in the non-portable os_flags */
          intval = osp->os_flags;
          if (should_bswap)
                  intval = BSWAP_64(intval);
          intval &= ~OBJSET_CRYPT_PORTABLE_FLAGS_MASK;
          if (!ZFS_HOST_BYTEORDER)
                  intval = BSWAP_64(intval);
  
          cd.cd_length = sizeof (uint64_t);
          cd.cd_raw.iov_base = (char *)&intval;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_update(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          /* add in fields from the user accounting dnodes */
          if (osp->os_userused_dnode.dn_type != DMU_OT_NONE) {
                  ret = zio_crypt_do_dnode_hmac_updates(ctx, key->zk_version,
                      should_bswap, &osp->os_userused_dnode);
                  if (ret)
                          goto error;
          }
  
          if (osp->os_groupused_dnode.dn_type != DMU_OT_NONE) {
                  ret = zio_crypt_do_dnode_hmac_updates(ctx, key->zk_version,
                      should_bswap, &osp->os_groupused_dnode);
                  if (ret)
                          goto error;
          }
  
          if (osp->os_projectused_dnode.dn_type != DMU_OT_NONE &&
              datalen >= OBJSET_PHYS_SIZE_V3) {
                  ret = zio_crypt_do_dnode_hmac_updates(ctx, key->zk_version,
                      should_bswap, &osp->os_projectused_dnode);
                  if (ret)
                          goto error;
          }
  
          /* store the final digest in a temporary buffer and copy what we need */
          cd.cd_length = SHA512_DIGEST_LENGTH;
          cd.cd_raw.iov_base = (char *)raw_local_mac;
          cd.cd_raw.iov_len = cd.cd_length;
  
          ret = crypto_mac_final(ctx, &cd);
          if (ret != CRYPTO_SUCCESS) {
                  ret = SET_ERROR(EIO);
                  goto error;
          }
  
          memcpy(local_mac, raw_local_mac, ZIO_OBJSET_MAC_LEN);
  
          return (0);
  
  error:
          memset(portable_mac, 0, ZIO_OBJSET_MAC_LEN);
          memset(local_mac, 0, ZIO_OBJSET_MAC_LEN);
          return (ret);
  }
  
  static void
  zio_crypt_destroy_uio(zfs_uio_t *uio)
  {
          if (uio->uio_iov)
                  kmem_free(uio->uio_iov, uio->uio_iovcnt * sizeof (iovec_t));
  }
  
  /*
   * This function parses an uncompressed indirect block and returns a checksum
   * of all the portable fields from all of the contained bps. The portable
   * fields are the MAC and all of the fields from blk_prop except for the dedup,
   * checksum, and psize bits. For an explanation of the purpose of this, see
   * the comment block on object set authentication.
   */
  static int
  zio_crypt_do_indirect_mac_checksum_impl(boolean_t generate, void *buf,
      uint_t datalen, uint64_t version, boolean_t byteswap, uint8_t *cksum)
  {
          blkptr_t *bp;
          int i, epb = datalen >> SPA_BLKPTRSHIFT;
          SHA2_CTX ctx;
          uint8_t digestbuf[SHA512_DIGEST_LENGTH];
  
          /* checksum all of the MACs from the layer below */
          SHA2Init(SHA512, &ctx);
          for (i = 0, bp = buf; i < epb; i++, bp++) {
                  zio_crypt_bp_do_indrect_checksum_updates(&ctx, version,
                      byteswap, bp);
          }
          SHA2Final(digestbuf, &ctx);
  
          if (generate) {
                  memcpy(cksum, digestbuf, ZIO_DATA_MAC_LEN);
                  return (0);
          }
  
          if (memcmp(digestbuf, cksum, ZIO_DATA_MAC_LEN) != 0)
                  return (SET_ERROR(ECKSUM));
  
          return (0);
  }
  
  int
  zio_crypt_do_indirect_mac_checksum(boolean_t generate, void *buf,
      uint_t datalen, boolean_t byteswap, uint8_t *cksum)
  {
          int ret;
  
          /*
           * Unfortunately, callers of this function will not always have
           * easy access to the on-disk format version. This info is
           * normally found in the DSL Crypto Key, but the checksum-of-MACs
           * is expected to be verifiable even when the key isn't loaded.
           * Here, instead of doing a ZAP lookup for the version for each
           * zio, we simply try both existing formats.
           */
          ret = zio_crypt_do_indirect_mac_checksum_impl(generate, buf,
              datalen, ZIO_CRYPT_KEY_CURRENT_VERSION, byteswap, cksum);
          if (ret == ECKSUM) {
                  ASSERT(!generate);
                  ret = zio_crypt_do_indirect_mac_checksum_impl(generate,
                      buf, datalen, 0, byteswap, cksum);
          }
  
          return (ret);
  }
  
  int
  zio_crypt_do_indirect_mac_checksum_abd(boolean_t generate, abd_t *abd,
      uint_t datalen, boolean_t byteswap, uint8_t *cksum)
  {
          int ret;
          void *buf;
  
          buf = abd_borrow_buf_copy(abd, datalen);
          ret = zio_crypt_do_indirect_mac_checksum(generate, buf, datalen,
              byteswap, cksum);
          abd_return_buf(abd, buf, datalen);
  
          return (ret);
  }
  
  /*
   * Special case handling routine for encrypting / decrypting ZIL blocks.
   * We do not check for the older ZIL chain because the encryption feature
   * was not available before the newer ZIL chain was introduced. The goal
   * here is to encrypt everything except the blkptr_t of a lr_write_t and
   * the zil_chain_t header. Everything that is not encrypted is authenticated.
   */
  static int
  zio_crypt_init_uios_zil(boolean_t encrypt, uint8_t *plainbuf,
      uint8_t *cipherbuf, uint_t datalen, boolean_t byteswap, zfs_uio_t *puio,
      zfs_uio_t *cuio, uint_t *enc_len, uint8_t **authbuf, uint_t *auth_len,
      boolean_t *no_crypt)
  {
          int ret;
          uint64_t txtype, lr_len;
          uint_t nr_src, nr_dst, crypt_len;
          uint_t aad_len = 0, nr_iovecs = 0, total_len = 0;
          iovec_t *src_iovecs = NULL, *dst_iovecs = NULL;
          uint8_t *src, *dst, *slrp, *dlrp, *blkend, *aadp;
          zil_chain_t *zilc;
          lr_t *lr;
          uint8_t *aadbuf = zio_buf_alloc(datalen);
  
          /* cipherbuf always needs an extra iovec for the MAC */
          if (encrypt) {
                  src = plainbuf;
                  dst = cipherbuf;
                  nr_src = 0;
                  nr_dst = 1;
          } else {
                  src = cipherbuf;
                  dst = plainbuf;
                  nr_src = 1;
                  nr_dst = 0;
          }
          memset(dst, 0, datalen);
  
          /* find the start and end record of the log block */
          zilc = (zil_chain_t *)src;
          slrp = src + sizeof (zil_chain_t);
          aadp = aadbuf;
          blkend = src + ((byteswap) ? BSWAP_64(zilc->zc_nused) : zilc->zc_nused);
  
          /* calculate the number of encrypted iovecs we will need */
          for (; slrp < blkend; slrp += lr_len) {
                  lr = (lr_t *)slrp;
  
                  if (!byteswap) {
                          txtype = lr->lrc_txtype;
                          lr_len = lr->lrc_reclen;
                  } else {
                          txtype = BSWAP_64(lr->lrc_txtype);
                          lr_len = BSWAP_64(lr->lrc_reclen);
                  }
  
                  nr_iovecs++;
                  if (txtype == TX_WRITE && lr_len != sizeof (lr_write_t))
                          nr_iovecs++;
          }
  
          nr_src += nr_iovecs;
          nr_dst += nr_iovecs;
  
          /* allocate the iovec arrays */
          if (nr_src != 0) {
                  src_iovecs = kmem_alloc(nr_src * sizeof (iovec_t), KM_SLEEP);
                  if (src_iovecs == NULL) {
                          ret = SET_ERROR(ENOMEM);
                          goto error;
                  }
          }
  
          if (nr_dst != 0) {
                  dst_iovecs = kmem_alloc(nr_dst * sizeof (iovec_t), KM_SLEEP);
                  if (dst_iovecs == NULL) {
                          ret = SET_ERROR(ENOMEM);
                          goto error;
                  }
          }
  
          /*
           * Copy the plain zil header over and authenticate everything except
           * the checksum that will store our MAC. If we are writing the data
           * the embedded checksum will not have been calculated yet, so we don't
           * authenticate that.
           */
          memcpy(dst, src, sizeof (zil_chain_t));
          memcpy(aadp, src, sizeof (zil_chain_t) - sizeof (zio_eck_t));
          aadp += sizeof (zil_chain_t) - sizeof (zio_eck_t);
          aad_len += sizeof (zil_chain_t) - sizeof (zio_eck_t);
  
          /* loop over records again, filling in iovecs */
          nr_iovecs = 0;
          slrp = src + sizeof (zil_chain_t);
          dlrp = dst + sizeof (zil_chain_t);
  
          for (; slrp < blkend; slrp += lr_len, dlrp += lr_len) {
                  lr = (lr_t *)slrp;
  
                  if (!byteswap) {
                          txtype = lr->lrc_txtype;
                          lr_len = lr->lrc_reclen;
                  } else {
                          txtype = BSWAP_64(lr->lrc_txtype);
                          lr_len = BSWAP_64(lr->lrc_reclen);
                  }
  
                  /* copy the common lr_t */
                  memcpy(dlrp, slrp, sizeof (lr_t));
                  memcpy(aadp, slrp, sizeof (lr_t));
                  aadp += sizeof (lr_t);
                  aad_len += sizeof (lr_t);
  
                  ASSERT3P(src_iovecs, !=, NULL);
                  ASSERT3P(dst_iovecs, !=, NULL);
  
                  /*
                   * If this is a TX_WRITE record we want to encrypt everything
                   * except the bp if exists. If the bp does exist we want to
                   * authenticate it.
                   */
                  if (txtype == TX_WRITE) {
                          crypt_len = sizeof (lr_write_t) -
                              sizeof (lr_t) - sizeof (blkptr_t);
                          src_iovecs[nr_iovecs].iov_base = slrp + sizeof (lr_t);
                          src_iovecs[nr_iovecs].iov_len = crypt_len;
                          dst_iovecs[nr_iovecs].iov_base = dlrp + sizeof (lr_t);
                          dst_iovecs[nr_iovecs].iov_len = crypt_len;
  
                          /* copy the bp now since it will not be encrypted */
                          memcpy(dlrp + sizeof (lr_write_t) - sizeof (blkptr_t),
                              slrp + sizeof (lr_write_t) - sizeof (blkptr_t),
                              sizeof (blkptr_t));
                          memcpy(aadp,
                              slrp + sizeof (lr_write_t) - sizeof (blkptr_t),
                              sizeof (blkptr_t));
                          aadp += sizeof (blkptr_t);
                          aad_len += sizeof (blkptr_t);
                          nr_iovecs++;
                          total_len += crypt_len;
  
                          if (lr_len != sizeof (lr_write_t)) {
                                  crypt_len = lr_len - sizeof (lr_write_t);
                                  src_iovecs[nr_iovecs].iov_base =
                                      slrp + sizeof (lr_write_t);
                                  src_iovecs[nr_iovecs].iov_len = crypt_len;
                                  dst_iovecs[nr_iovecs].iov_base =
                                      dlrp + sizeof (lr_write_t);
                                  dst_iovecs[nr_iovecs].iov_len = crypt_len;
                                  nr_iovecs++;
                                  total_len += crypt_len;
                          }
                  } else {
                          crypt_len = lr_len - sizeof (lr_t);
                          src_iovecs[nr_iovecs].iov_base = slrp + sizeof (lr_t);
                          src_iovecs[nr_iovecs].iov_len = crypt_len;
                          dst_iovecs[nr_iovecs].iov_base = dlrp + sizeof (lr_t);
                          dst_iovecs[nr_iovecs].iov_len = crypt_len;
                          nr_iovecs++;
                          total_len += crypt_len;
                  }
          }
  
          *no_crypt = (nr_iovecs == 0);
          *enc_len = total_len;
          *authbuf = aadbuf;
          *auth_len = aad_len;
  
          if (encrypt) {
                  puio->uio_iov = src_iovecs;
                  puio->uio_iovcnt = nr_src;
                  cuio->uio_iov = dst_iovecs;
                  cuio->uio_iovcnt = nr_dst;
          } else {
                  puio->uio_iov = dst_iovecs;
                  puio->uio_iovcnt = nr_dst;
                  cuio->uio_iov = src_iovecs;
                  cuio->uio_iovcnt = nr_src;
          }
  
          return (0);
  
  error:
          zio_buf_free(aadbuf, datalen);
          if (src_iovecs != NULL)
                  kmem_free(src_iovecs, nr_src * sizeof (iovec_t));
          if (dst_iovecs != NULL)
                  kmem_free(dst_iovecs, nr_dst * sizeof (iovec_t));
  
          *enc_len = 0;
          *authbuf = NULL;
          *auth_len = 0;
          *no_crypt = B_FALSE;
          puio->uio_iov = NULL;
          puio->uio_iovcnt = 0;
          cuio->uio_iov = NULL;
          cuio->uio_iovcnt = 0;
          return (ret);
  }
  
  /*
   * Special case handling routine for encrypting / decrypting dnode blocks.
   */
  static int
  zio_crypt_init_uios_dnode(boolean_t encrypt, uint64_t version,
      uint8_t *plainbuf, uint8_t *cipherbuf, uint_t datalen, boolean_t byteswap,
      zfs_uio_t *puio, zfs_uio_t *cuio, uint_t *enc_len, uint8_t **authbuf,
      uint_t *auth_len, boolean_t *no_crypt)
  {
          int ret;
          uint_t nr_src, nr_dst, crypt_len;
          uint_t aad_len = 0, nr_iovecs = 0, total_len = 0;
          uint_t i, j, max_dnp = datalen >> DNODE_SHIFT;
          iovec_t *src_iovecs = NULL, *dst_iovecs = NULL;
          uint8_t *src, *dst, *aadp;
          dnode_phys_t *dnp, *adnp, *sdnp, *ddnp;
          uint8_t *aadbuf = zio_buf_alloc(datalen);
  
          if (encrypt) {
                  src = plainbuf;
                  dst = cipherbuf;
                  nr_src = 0;
                  nr_dst = 1;
          } else {
                  src = cipherbuf;
                  dst = plainbuf;
                  nr_src = 1;
                  nr_dst = 0;
          }
  
          sdnp = (dnode_phys_t *)src;
          ddnp = (dnode_phys_t *)dst;
          aadp = aadbuf;
  
          /*
           * Count the number of iovecs we will need to do the encryption by
           * counting the number of bonus buffers that need to be encrypted.
           */
          for (i = 0; i < max_dnp; i += sdnp[i].dn_extra_slots + 1) {
                  /*
                   * This block may still be byteswapped. However, all of the
                   * values we use are either uint8_t's (for which byteswapping
                   * is a noop) or a * != 0 check, which will work regardless
                   * of whether or not we byteswap.
                   */
                  if (sdnp[i].dn_type != DMU_OT_NONE &&
                      DMU_OT_IS_ENCRYPTED(sdnp[i].dn_bonustype) &&
                      sdnp[i].dn_bonuslen != 0) {
                          nr_iovecs++;
                  }
          }
  
          nr_src += nr_iovecs;
          nr_dst += nr_iovecs;
  
          if (nr_src != 0) {
                  src_iovecs = kmem_alloc(nr_src * sizeof (iovec_t), KM_SLEEP);
                  if (src_iovecs == NULL) {
                          ret = SET_ERROR(ENOMEM);
                          goto error;
                  }
          }
  
          if (nr_dst != 0) {
                  dst_iovecs = kmem_alloc(nr_dst * sizeof (iovec_t), KM_SLEEP);
                  if (dst_iovecs == NULL) {
                          ret = SET_ERROR(ENOMEM);
                          goto error;
                  }
          }
  
          nr_iovecs = 0;
  
          /*
           * Iterate through the dnodes again, this time filling in the uios
           * we allocated earlier. We also concatenate any data we want to
           * authenticate onto aadbuf.
           */
          for (i = 0; i < max_dnp; i += sdnp[i].dn_extra_slots + 1) {
                  dnp = &sdnp[i];
  
                  /* copy over the core fields and blkptrs (kept as plaintext) */
                  memcpy(&ddnp[i], dnp,
                      (uint8_t *)DN_BONUS(dnp) - (uint8_t *)dnp);
  
                  if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
                          memcpy(DN_SPILL_BLKPTR(&ddnp[i]), DN_SPILL_BLKPTR(dnp),
                              sizeof (blkptr_t));
                  }
  
                  /*
                   * Handle authenticated data. We authenticate everything in
                   * the dnode that can be brought over when we do a raw send.
                   * This includes all of the core fields as well as the MACs
                   * stored in the bp checksums and all of the portable bits
                   * from blk_prop. We include the dnode padding here in case it
                   * ever gets used in the future. Some dn_flags and dn_used are
                   * not portable so we mask those out values out of the
                   * authenticated data.
                   */
                  crypt_len = offsetof(dnode_phys_t, dn_blkptr);
                  memcpy(aadp, dnp, crypt_len);
                  adnp = (dnode_phys_t *)aadp;
                  adnp->dn_flags &= DNODE_CRYPT_PORTABLE_FLAGS_MASK;
                  adnp->dn_used = 0;
                  aadp += crypt_len;
                  aad_len += crypt_len;
  
                  for (j = 0; j < dnp->dn_nblkptr; j++) {
                          zio_crypt_bp_do_aad_updates(&aadp, &aad_len,
                              version, byteswap, &dnp->dn_blkptr[j]);
                  }
  
                  if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
                          zio_crypt_bp_do_aad_updates(&aadp, &aad_len,
                              version, byteswap, DN_SPILL_BLKPTR(dnp));
                  }
  
                  /*
                   * If this bonus buffer needs to be encrypted, we prepare an
                   * iovec_t. The encryption / decryption functions will fill
                   * this in for us with the encrypted or decrypted data.
                   * Otherwise we add the bonus buffer to the authenticated
                   * data buffer and copy it over to the destination. The
                   * encrypted iovec extends to DN_MAX_BONUS_LEN(dnp) so that
                   * we can guarantee alignment with the AES block size
                   * (128 bits).
                   */
                  crypt_len = DN_MAX_BONUS_LEN(dnp);
                  if (dnp->dn_type != DMU_OT_NONE &&
                      DMU_OT_IS_ENCRYPTED(dnp->dn_bonustype) &&
                      dnp->dn_bonuslen != 0) {
                          ASSERT3U(nr_iovecs, <, nr_src);
                          ASSERT3U(nr_iovecs, <, nr_dst);
                          ASSERT3P(src_iovecs, !=, NULL);
                          ASSERT3P(dst_iovecs, !=, NULL);
                          src_iovecs[nr_iovecs].iov_base = DN_BONUS(dnp);
                          src_iovecs[nr_iovecs].iov_len = crypt_len;
                          dst_iovecs[nr_iovecs].iov_base = DN_BONUS(&ddnp[i]);
                          dst_iovecs[nr_iovecs].iov_len = crypt_len;
  
                          nr_iovecs++;
                          total_len += crypt_len;
                  } else {
                          memcpy(DN_BONUS(&ddnp[i]), DN_BONUS(dnp), crypt_len);
                          memcpy(aadp, DN_BONUS(dnp), crypt_len);
                          aadp += crypt_len;
                          aad_len += crypt_len;
                  }
          }
  
          *no_crypt = (nr_iovecs == 0);
          *enc_len = total_len;
          *authbuf = aadbuf;
          *auth_len = aad_len;
  
          if (encrypt) {
                  puio->uio_iov = src_iovecs;
                  puio->uio_iovcnt = nr_src;
                  cuio->uio_iov = dst_iovecs;
                  cuio->uio_iovcnt = nr_dst;
          } else {
                  puio->uio_iov = dst_iovecs;
                  puio->uio_iovcnt = nr_dst;
                  cuio->uio_iov = src_iovecs;
                  cuio->uio_iovcnt = nr_src;
          }
  
          return (0);
  
  error:
          zio_buf_free(aadbuf, datalen);
          if (src_iovecs != NULL)
                  kmem_free(src_iovecs, nr_src * sizeof (iovec_t));
          if (dst_iovecs != NULL)
                  kmem_free(dst_iovecs, nr_dst * sizeof (iovec_t));
  
          *enc_len = 0;
          *authbuf = NULL;
          *auth_len = 0;
          *no_crypt = B_FALSE;
          puio->uio_iov = NULL;
          puio->uio_iovcnt = 0;
          cuio->uio_iov = NULL;
          cuio->uio_iovcnt = 0;
          return (ret);
  }
  
  static int
  zio_crypt_init_uios_normal(boolean_t encrypt, uint8_t *plainbuf,
      uint8_t *cipherbuf, uint_t datalen, zfs_uio_t *puio, zfs_uio_t *cuio,
      uint_t *enc_len)
  {
          (void) encrypt;
          int ret;
          uint_t nr_plain = 1, nr_cipher = 2;
          iovec_t *plain_iovecs = NULL, *cipher_iovecs = NULL;
  
          /* allocate the iovecs for the plain and cipher data */
          plain_iovecs = kmem_alloc(nr_plain * sizeof (iovec_t),
              KM_SLEEP);
          if (!plain_iovecs) {
                  ret = SET_ERROR(ENOMEM);
                  goto error;
          }
  
          cipher_iovecs = kmem_alloc(nr_cipher * sizeof (iovec_t),
              KM_SLEEP);
          if (!cipher_iovecs) {
                  ret = SET_ERROR(ENOMEM);
                  goto error;
          }
  
          plain_iovecs[0].iov_base = plainbuf;
          plain_iovecs[0].iov_len = datalen;
          cipher_iovecs[0].iov_base = cipherbuf;
          cipher_iovecs[0].iov_len = datalen;
  
          *enc_len = datalen;
          puio->uio_iov = plain_iovecs;
          puio->uio_iovcnt = nr_plain;
          cuio->uio_iov = cipher_iovecs;
          cuio->uio_iovcnt = nr_cipher;
  
          return (0);
  
  error:
          if (plain_iovecs != NULL)
                  kmem_free(plain_iovecs, nr_plain * sizeof (iovec_t));
          if (cipher_iovecs != NULL)
                  kmem_free(cipher_iovecs, nr_cipher * sizeof (iovec_t));
  
          *enc_len = 0;
          puio->uio_iov = NULL;
          puio->uio_iovcnt = 0;
          cuio->uio_iov = NULL;
          cuio->uio_iovcnt = 0;
          return (ret);
  }
  
  /*
   * This function builds up the plaintext (puio) and ciphertext (cuio) uios so
   * that they can be used for encryption and decryption by zio_do_crypt_uio().
   * Most blocks will use zio_crypt_init_uios_normal(), with ZIL and dnode blocks
   * requiring special handling to parse out pieces that are to be encrypted. The
   * authbuf is used by these special cases to store additional authenticated
   * data (AAD) for the encryption modes.
   */
  static int
  zio_crypt_init_uios(boolean_t encrypt, uint64_t version, dmu_object_type_t ot,
      uint8_t *plainbuf, uint8_t *cipherbuf, uint_t datalen, boolean_t byteswap,
      uint8_t *mac, zfs_uio_t *puio, zfs_uio_t *cuio, uint_t *enc_len,
      uint8_t **authbuf, uint_t *auth_len, boolean_t *no_crypt)
  {
          int ret;
          iovec_t *mac_iov;
  
          ASSERT(DMU_OT_IS_ENCRYPTED(ot) || ot == DMU_OT_NONE);
  
          /* route to handler */
          switch (ot) {
          case DMU_OT_INTENT_LOG:
                  ret = zio_crypt_init_uios_zil(encrypt, plainbuf, cipherbuf,
                      datalen, byteswap, puio, cuio, enc_len, authbuf, auth_len,
                      no_crypt);
                  break;
          case DMU_OT_DNODE:
                  ret = zio_crypt_init_uios_dnode(encrypt, version, plainbuf,
                      cipherbuf, datalen, byteswap, puio, cuio, enc_len, authbuf,
                      auth_len, no_crypt);
                  break;
          default:
                  ret = zio_crypt_init_uios_normal(encrypt, plainbuf, cipherbuf,
                      datalen, puio, cuio, enc_len);
                  *authbuf = NULL;
                  *auth_len = 0;
                  *no_crypt = B_FALSE;
                  break;
          }
  
          if (ret != 0)
                  goto error;
  
          /* populate the uios */
          puio->uio_segflg = UIO_SYSSPACE;
          cuio->uio_segflg = UIO_SYSSPACE;
  
          mac_iov = ((iovec_t *)&cuio->uio_iov[cuio->uio_iovcnt - 1]);
          mac_iov->iov_base = mac;
          mac_iov->iov_len = ZIO_DATA_MAC_LEN;
  
          return (0);
  
  error:
          return (ret);
  }
  
  /*
   * Primary encryption / decryption entrypoint for zio data.
   */
  int
  zio_do_crypt_data(boolean_t encrypt, zio_crypt_key_t *key,
      dmu_object_type_t ot, boolean_t byteswap, uint8_t *salt, uint8_t *iv,
      uint8_t *mac, uint_t datalen, uint8_t *plainbuf, uint8_t *cipherbuf,
      boolean_t *no_crypt)
  {
          int ret;
          boolean_t locked = B_FALSE;
          uint64_t crypt = key->zk_crypt;
          uint_t keydata_len = zio_crypt_table[crypt].ci_keylen;
          uint_t enc_len, auth_len;
          zfs_uio_t puio, cuio;
          uint8_t enc_keydata[MASTER_KEY_MAX_LEN];
          crypto_key_t tmp_ckey, *ckey = NULL;
          crypto_ctx_template_t tmpl;
          uint8_t *authbuf = NULL;
  
          memset(&puio, 0, sizeof (puio));
          memset(&cuio, 0, sizeof (cuio));
  
          /*
           * If the needed key is the current one, just use it. Otherwise we
           * need to generate a temporary one from the given salt + master key.
           * If we are encrypting, we must return a copy of the current salt
           * so that it can be stored in the blkptr_t.
           */
          rw_enter(&key->zk_salt_lock, RW_READER);
          locked = B_TRUE;
  
          if (memcmp(salt, key->zk_salt, ZIO_DATA_SALT_LEN) == 0) {
                  ckey = &key->zk_current_key;
                  tmpl = key->zk_current_tmpl;
          } else {
                  rw_exit(&key->zk_salt_lock);
                  locked = B_FALSE;
  
                  ret = hkdf_sha512(key->zk_master_keydata, keydata_len, NULL, 0,
                      salt, ZIO_DATA_SALT_LEN, enc_keydata, keydata_len);
                  if (ret != 0)
                          goto error;
  
                  tmp_ckey.ck_data = enc_keydata;
                  tmp_ckey.ck_length = CRYPTO_BYTES2BITS(keydata_len);
  
                  ckey = &tmp_ckey;
                  tmpl = NULL;
          }
  
          /*
           * Attempt to use QAT acceleration if we can. We currently don't
           * do this for metadnode and ZIL blocks, since they have a much
           * more involved buffer layout and the qat_crypt() function only
           * works in-place.
           */
          if (qat_crypt_use_accel(datalen) &&
              ot != DMU_OT_INTENT_LOG && ot != DMU_OT_DNODE) {
                  uint8_t *srcbuf, *dstbuf;
  
                  if (encrypt) {
                          srcbuf = plainbuf;
                          dstbuf = cipherbuf;
                  } else {
                          srcbuf = cipherbuf;
                          dstbuf = plainbuf;
                  }
  
                  ret = qat_crypt((encrypt) ? QAT_ENCRYPT : QAT_DECRYPT, srcbuf,
                      dstbuf, NULL, 0, iv, mac, ckey, key->zk_crypt, datalen);
                  if (ret == CPA_STATUS_SUCCESS) {
                          if (locked) {
                                  rw_exit(&key->zk_salt_lock);
                                  locked = B_FALSE;
                          }
  
                          return (0);
                  }
                  /* If the hardware implementation fails fall back to software */
          }
  
          /* create uios for encryption */
          ret = zio_crypt_init_uios(encrypt, key->zk_version, ot, plainbuf,
              cipherbuf, datalen, byteswap, mac, &puio, &cuio, &enc_len,
              &authbuf, &auth_len, no_crypt);
          if (ret != 0)
                  goto error;
  
          /* perform the encryption / decryption in software */
          ret = zio_do_crypt_uio(encrypt, key->zk_crypt, ckey, tmpl, iv, enc_len,
              &puio, &cuio, authbuf, auth_len);
          if (ret != 0)
                  goto error;
  
          if (locked) {
                  rw_exit(&key->zk_salt_lock);
          }
  
          if (authbuf != NULL)
                  zio_buf_free(authbuf, datalen);
          if (ckey == &tmp_ckey)
                  memset(enc_keydata, 0, keydata_len);
          zio_crypt_destroy_uio(&puio);
          zio_crypt_destroy_uio(&cuio);
  
          return (0);
  
  error:
          if (locked)
                  rw_exit(&key->zk_salt_lock);
          if (authbuf != NULL)
                  zio_buf_free(authbuf, datalen);
          if (ckey == &tmp_ckey)
                  memset(enc_keydata, 0, keydata_len);
          zio_crypt_destroy_uio(&puio);
          zio_crypt_destroy_uio(&cuio);
  
          return (ret);
  }
  
  /*
   * Simple wrapper around zio_do_crypt_data() to work with abd's instead of
   * linear buffers.
   */
  int
  zio_do_crypt_abd(boolean_t encrypt, zio_crypt_key_t *key, dmu_object_type_t ot,
      boolean_t byteswap, uint8_t *salt, uint8_t *iv, uint8_t *mac,
      uint_t datalen, abd_t *pabd, abd_t *cabd, boolean_t *no_crypt)
  {
          int ret;
          void *ptmp, *ctmp;
  
          if (encrypt) {
                  ptmp = abd_borrow_buf_copy(pabd, datalen);
                  ctmp = abd_borrow_buf(cabd, datalen);
          } else {
                  ptmp = abd_borrow_buf(pabd, datalen);
                  ctmp = abd_borrow_buf_copy(cabd, datalen);
          }
  
          ret = zio_do_crypt_data(encrypt, key, ot, byteswap, salt, iv, mac,
              datalen, ptmp, ctmp, no_crypt);
          if (ret != 0)
                  goto error;
  
          if (encrypt) {
                  abd_return_buf(pabd, ptmp, datalen);
                  abd_return_buf_copy(cabd, ctmp, datalen);
          } else {
                  abd_return_buf_copy(pabd, ptmp, datalen);
                  abd_return_buf(cabd, ctmp, datalen);
          }
  
          return (0);
  
  error:
          if (encrypt) {
                  abd_return_buf(pabd, ptmp, datalen);
                  abd_return_buf_copy(cabd, ctmp, datalen);
          } else {
                  abd_return_buf_copy(pabd, ptmp, datalen);
                  abd_return_buf(cabd, ctmp, datalen);
          }
  
          return (ret);
  }
  
  #if defined(_KERNEL)
  /* CSTYLED */
  module_param(zfs_key_max_salt_uses, ulong, 0644);
  MODULE_PARM_DESC(zfs_key_max_salt_uses, "Max number of times a salt value "
          "can be used for generating encryption keys before it is rotated");
  #endif

Cache object: eae9e4df2be2f20c588c4bdaa82162b2