/* * 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 #include #include #include #include #include #include #include #include /* * 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"} }; static void zio_crypt_key_destroy_early(zio_crypt_key_t *key) { rw_destroy(&key->zk_salt_lock); /* free crypto templates */ memset(&key->zk_session, 0, sizeof (key->zk_session)); /* zero out sensitive data */ memset(key, 0, sizeof (zio_crypt_key_t)); } void zio_crypt_key_destroy(zio_crypt_key_t *key) { freebsd_crypt_freesession(&key->zk_session); zio_crypt_key_destroy_early(key); } int zio_crypt_key_init(uint64_t crypt, zio_crypt_key_t *key) { int ret; crypto_mechanism_t mech __unused; uint_t keydata_len; const zio_crypt_info_t *ci = NULL; ASSERT3P(key, !=, NULL); ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS); ci = &zio_crypt_table[crypt]; if (ci->ci_crypt_type != ZC_TYPE_GCM && ci->ci_crypt_type != ZC_TYPE_CCM) return (ENOTSUP); keydata_len = zio_crypt_table[crypt].ci_keylen; 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); ci = &zio_crypt_table[crypt]; if (ci->ci_crypt_type != ZC_TYPE_GCM && ci->ci_crypt_type != ZC_TYPE_CCM) return (ENOTSUP); ret = freebsd_crypt_newsession(&key->zk_session, ci, &key->zk_current_key); if (ret) goto error; key->zk_crypt = crypt; key->zk_version = ZIO_CRYPT_KEY_CURRENT_VERSION; key->zk_salt_count = 0; return (0); error: zio_crypt_key_destroy_early(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 __unused; 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; freebsd_crypt_freesession(&key->zk_session); ret = freebsd_crypt_newsession(&key->zk_session, &zio_crypt_table[key->zk_crypt], &key->zk_current_key); if (ret != 0) goto out_unlock; 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); } void *failed_decrypt_buf; int failed_decrypt_size; /* * 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. */ /* * The implementation for FreeBSD's OpenCrypto. * * The big difference between ICP and FOC is that FOC uses a single * buffer for input and output. This means that (for AES-GCM, the * only one supported right now) the source must be copied into the * destination, and the destination must have the AAD, and the tag/MAC, * already associated with it. (Both implementations can use a uio.) * * Since the auth data is part of the iovec array, all we need to know * is the length: 0 means there's no AAD. * */ static int zio_do_crypt_uio_opencrypto(boolean_t encrypt, freebsd_crypt_session_t *sess, uint64_t crypt, crypto_key_t *key, uint8_t *ivbuf, uint_t datalen, zfs_uio_t *uio, uint_t auth_len) { const zio_crypt_info_t *ci = &zio_crypt_table[crypt]; if (ci->ci_crypt_type != ZC_TYPE_GCM && ci->ci_crypt_type != ZC_TYPE_CCM) return (ENOTSUP); int ret = freebsd_crypt_uio(encrypt, sess, ci, uio, key, ivbuf, datalen, auth_len); if (ret != 0) { #ifdef FCRYPTO_DEBUG printf("%s(%d): Returning error %s\n", __FUNCTION__, __LINE__, encrypt ? "EIO" : "ECKSUM"); #endif ret = SET_ERROR(encrypt ? EIO : ECKSUM); } 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; uint64_t aad[3]; /* * With OpenCrypto in FreeBSD, the same buffer is used for * input and output. Also, the AAD (for AES-GMC at least) * needs to logically go in front. */ zfs_uio_t cuio; struct uio cuio_s; iovec_t iovecs[4]; uint64_t crypt = key->zk_crypt; uint_t enc_len, keydata_len, aad_len; ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS); zfs_uio_init(&cuio, &cuio_s); 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; /* * Since we only support one buffer, we need to copy * the plain text (source) to the cipher buffer (dest). * We set iovecs[0] -- the authentication data -- below. */ memcpy(keydata_out, key->zk_master_keydata, keydata_len); memcpy(hmac_keydata_out, key->zk_hmac_keydata, SHA512_HMAC_KEYLEN); iovecs[1].iov_base = keydata_out; iovecs[1].iov_len = keydata_len; iovecs[2].iov_base = hmac_keydata_out; iovecs[2].iov_len = SHA512_HMAC_KEYLEN; iovecs[3].iov_base = mac; iovecs[3].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); } iovecs[0].iov_base = aad; iovecs[0].iov_len = aad_len; enc_len = zio_crypt_table[crypt].ci_keylen + SHA512_HMAC_KEYLEN; GET_UIO_STRUCT(&cuio)->uio_iov = iovecs; zfs_uio_iovcnt(&cuio) = 4; zfs_uio_segflg(&cuio) = UIO_SYSSPACE; /* encrypt the keys and store the resulting ciphertext and mac */ ret = zio_do_crypt_uio_opencrypto(B_TRUE, NULL, crypt, cwkey, iv, enc_len, &cuio, 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) { int ret; uint64_t aad[3]; /* * With OpenCrypto in FreeBSD, the same buffer is used for * input and output. Also, the AAD (for AES-GMC at least) * needs to logically go in front. */ zfs_uio_t cuio; struct uio cuio_s; iovec_t iovecs[4]; void *src, *dst; uint_t enc_len, keydata_len, aad_len; ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS); keydata_len = zio_crypt_table[crypt].ci_keylen; rw_init(&key->zk_salt_lock, NULL, RW_DEFAULT, NULL); zfs_uio_init(&cuio, &cuio_s); /* * Since we only support one buffer, we need to copy * the encrypted buffer (source) to the plain buffer * (dest). We set iovecs[0] -- the authentication data -- * below. */ dst = key->zk_master_keydata; src = keydata; memcpy(dst, src, keydata_len); dst = key->zk_hmac_keydata; src = hmac_keydata; memcpy(dst, src, SHA512_HMAC_KEYLEN); iovecs[1].iov_base = key->zk_master_keydata; iovecs[1].iov_len = keydata_len; iovecs[2].iov_base = key->zk_hmac_keydata; iovecs[2].iov_len = SHA512_HMAC_KEYLEN; iovecs[3].iov_base = mac; iovecs[3].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; iovecs[0].iov_base = aad; iovecs[0].iov_len = aad_len; GET_UIO_STRUCT(&cuio)->uio_iov = iovecs; zfs_uio_iovcnt(&cuio) = 4; zfs_uio_segflg(&cuio) = UIO_SYSSPACE; /* decrypt the keys and store the result in the output buffers */ ret = zio_do_crypt_uio_opencrypto(B_FALSE, NULL, crypt, cwkey, iv, enc_len, &cuio, 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); ret = freebsd_crypt_newsession(&key->zk_session, &zio_crypt_table[crypt], &key->zk_current_key); if (ret != 0) goto error; key->zk_crypt = crypt; key->zk_version = version; key->zk_guid = guid; key->zk_salt_count = 0; return (0); error: zio_crypt_key_destroy_early(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) { uint8_t raw_digestbuf[SHA512_DIGEST_LENGTH]; ASSERT3U(digestlen, <=, SHA512_DIGEST_LENGTH); crypto_mac(&key->zk_hmac_key, data, datalen, raw_digestbuf, SHA512_DIGEST_LENGTH); memcpy(digestbuf, raw_digestbuf, digestlen); return (0); } 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) { int avoidlint = SPA_MINBLOCKSIZE; /* * 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, avoidlint); 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, avoidlint); } 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) { uint_t bab_len; blkptr_auth_buf_t bab; zio_crypt_bp_auth_init(version, should_bswap, bp, &bab, &bab_len); crypto_mac_update(ctx, &bab, bab_len); return (0); } 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; boolean_t le_bswap = (should_bswap == ZFS_HOST_BYTEORDER); uint8_t tmp_dncore[offsetof(dnode_phys_t, dn_blkptr)]; /* authenticate the core dnode (masking out non-portable bits) */ memcpy(tmp_dncore, dnp, sizeof (tmp_dncore)); adnp = (dnode_phys_t *)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; crypto_mac_update(ctx, adnp, sizeof (tmp_dncore)); 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; struct hmac_ctx hash_ctx; struct hmac_ctx *ctx = &hash_ctx; 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]; /* calculate the portable MAC from the portable fields and metadnode */ crypto_mac_init(ctx, &key->zk_hmac_key); /* add in the os_type */ intval = (le_bswap) ? osp->os_type : BSWAP_64(osp->os_type); crypto_mac_update(ctx, &intval, sizeof (uint64_t)); /* 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); crypto_mac_update(ctx, &intval, sizeof (uint64_t)); /* 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; crypto_mac_final(ctx, raw_portable_mac, SHA512_DIGEST_LENGTH); 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 */ crypto_mac_init(ctx, &key->zk_hmac_key); /* 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); crypto_mac_update(ctx, &intval, sizeof (uint64_t)); /* XXX check dnode type ... */ /* 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; } crypto_mac_final(ctx, raw_local_mac, SHA512_DIGEST_LENGTH); 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 (GET_UIO_STRUCT(uio)->uio_iov) kmem_free(GET_UIO_STRUCT(uio)->uio_iov, zfs_uio_iovcnt(uio) * 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) { #ifdef FCRYPTO_DEBUG printf("%s(%d): Setting ECKSUM\n", __FUNCTION__, __LINE__); #endif 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. */ /* * The OpenCrypto used in FreeBSD does not use separate source and * destination buffers; instead, the same buffer is used. Further, to * accommodate some of the drivers, the authbuf needs to be logically before * the data. This means that we need to copy the source to the destination, * and set up an extra iovec_t at the beginning to handle the authbuf. * It also means we'll only return one zfs_uio_t. */ 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 *out_uio, uint_t *enc_len, uint8_t **authbuf, uint_t *auth_len, boolean_t *no_crypt) { (void) puio; uint8_t *aadbuf = zio_buf_alloc(datalen); uint8_t *src, *dst, *slrp, *dlrp, *blkend, *aadp; iovec_t *dst_iovecs; zil_chain_t *zilc; lr_t *lr; uint64_t txtype, lr_len; uint_t crypt_len, nr_iovecs, vec; uint_t aad_len = 0, total_len = 0; if (encrypt) { src = plainbuf; dst = cipherbuf; } else { src = cipherbuf; dst = plainbuf; } memcpy(dst, src, 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. */ /* We need at least two iovecs -- one for the AAD, one for the MAC. */ nr_iovecs = 2; for (; slrp < blkend; slrp += lr_len) { lr = (lr_t *)slrp; if (byteswap) { txtype = BSWAP_64(lr->lrc_txtype); lr_len = BSWAP_64(lr->lrc_reclen); } else { txtype = lr->lrc_txtype; lr_len = lr->lrc_reclen; } nr_iovecs++; if (txtype == TX_WRITE && lr_len != sizeof (lr_write_t)) nr_iovecs++; } dst_iovecs = kmem_alloc(nr_iovecs * sizeof (iovec_t), KM_SLEEP); /* * 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(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); slrp = src + sizeof (zil_chain_t); dlrp = dst + sizeof (zil_chain_t); /* * Loop over records again, filling in iovecs. */ /* The first iovec will contain the authbuf. */ vec = 1; 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); /* * 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); dst_iovecs[vec].iov_base = (char *)dlrp + sizeof (lr_t); dst_iovecs[vec].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); vec++; total_len += crypt_len; if (lr_len != sizeof (lr_write_t)) { crypt_len = lr_len - sizeof (lr_write_t); dst_iovecs[vec].iov_base = (char *) dlrp + sizeof (lr_write_t); dst_iovecs[vec].iov_len = crypt_len; vec++; total_len += crypt_len; } } else { crypt_len = lr_len - sizeof (lr_t); dst_iovecs[vec].iov_base = (char *)dlrp + sizeof (lr_t); dst_iovecs[vec].iov_len = crypt_len; vec++; total_len += crypt_len; } } /* The last iovec will contain the MAC. */ ASSERT3U(vec, ==, nr_iovecs - 1); /* AAD */ dst_iovecs[0].iov_base = aadbuf; dst_iovecs[0].iov_len = aad_len; /* MAC */ dst_iovecs[vec].iov_base = 0; dst_iovecs[vec].iov_len = 0; *no_crypt = (vec == 1); *enc_len = total_len; *authbuf = aadbuf; *auth_len = aad_len; GET_UIO_STRUCT(out_uio)->uio_iov = dst_iovecs; zfs_uio_iovcnt(out_uio) = nr_iovecs; return (0); } /* * 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 *out_uio, uint_t *enc_len, uint8_t **authbuf, uint_t *auth_len, boolean_t *no_crypt) { uint8_t *aadbuf = zio_buf_alloc(datalen); uint8_t *src, *dst, *aadp; dnode_phys_t *dnp, *adnp, *sdnp, *ddnp; iovec_t *dst_iovecs; uint_t nr_iovecs, crypt_len, vec; uint_t aad_len = 0, total_len = 0; uint_t i, j, max_dnp = datalen >> DNODE_SHIFT; if (encrypt) { src = plainbuf; dst = cipherbuf; } else { src = cipherbuf; dst = plainbuf; } memcpy(dst, src, datalen); 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. */ /* We need at least two iovecs -- one for the AAD, one for the MAC. */ nr_iovecs = 2; 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++; } } dst_iovecs = kmem_alloc(nr_iovecs * sizeof (iovec_t), KM_SLEEP); /* * 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. */ /* The first iovec will contain the authbuf. */ vec = 1; 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) { dst_iovecs[vec].iov_base = DN_BONUS(&ddnp[i]); dst_iovecs[vec].iov_len = crypt_len; vec++; 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; } } /* The last iovec will contain the MAC. */ ASSERT3U(vec, ==, nr_iovecs - 1); /* AAD */ dst_iovecs[0].iov_base = aadbuf; dst_iovecs[0].iov_len = aad_len; /* MAC */ dst_iovecs[vec].iov_base = 0; dst_iovecs[vec].iov_len = 0; *no_crypt = (vec == 1); *enc_len = total_len; *authbuf = aadbuf; *auth_len = aad_len; GET_UIO_STRUCT(out_uio)->uio_iov = dst_iovecs; zfs_uio_iovcnt(out_uio) = nr_iovecs; return (0); } 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 *out_uio, uint_t *enc_len) { (void) puio; int ret; uint_t nr_plain = 1, nr_cipher = 2; iovec_t *plain_iovecs = NULL, *cipher_iovecs = NULL; void *src, *dst; cipher_iovecs = kmem_zalloc(nr_cipher * sizeof (iovec_t), KM_SLEEP); if (!cipher_iovecs) { ret = SET_ERROR(ENOMEM); goto error; } if (encrypt) { src = plainbuf; dst = cipherbuf; } else { src = cipherbuf; dst = plainbuf; } memcpy(dst, src, datalen); cipher_iovecs[0].iov_base = dst; cipher_iovecs[0].iov_len = datalen; *enc_len = datalen; GET_UIO_STRUCT(out_uio)->uio_iov = cipher_iovecs; zfs_uio_iovcnt(out_uio) = 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; GET_UIO_STRUCT(out_uio)->uio_iov = NULL; zfs_uio_iovcnt(out_uio) = 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 */ zfs_uio_segflg(cuio) = UIO_SYSSPACE; mac_iov = ((iovec_t *)&(GET_UIO_STRUCT(cuio)-> uio_iov[zfs_uio_iovcnt(cuio) - 1])); mac_iov->iov_base = (void *)mac; mac_iov->iov_len = ZIO_DATA_MAC_LEN; return (0); error: return (ret); } void *failed_decrypt_buf; int faile_decrypt_size; /* * 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; struct uio puio_s, cuio_s; uint8_t enc_keydata[MASTER_KEY_MAX_LEN]; crypto_key_t tmp_ckey, *ckey = NULL; freebsd_crypt_session_t *tmpl = NULL; uint8_t *authbuf = NULL; zfs_uio_init(&puio, &puio_s); zfs_uio_init(&cuio, &cuio_s); memset(GET_UIO_STRUCT(&puio), 0, sizeof (struct uio)); memset(GET_UIO_STRUCT(&cuio), 0, sizeof (struct uio)); #ifdef FCRYPTO_DEBUG printf("%s(%s, %p, %p, %d, %p, %p, %u, %s, %p, %p, %p)\n", __FUNCTION__, encrypt ? "encrypt" : "decrypt", key, salt, ot, iv, mac, datalen, byteswap ? "byteswap" : "native_endian", plainbuf, cipherbuf, no_crypt); printf("\tkey = {"); for (int i = 0; i < key->zk_current_key.ck_length/8; i++) printf("%02x ", ((uint8_t *)key->zk_current_key.ck_data)[i]); printf("}\n"); #endif /* 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) return (ret); /* * 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_session; } 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; } /* perform the encryption / decryption */ ret = zio_do_crypt_uio_opencrypto(encrypt, tmpl, key->zk_crypt, ckey, iv, enc_len, &cuio, 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 (!encrypt) { if (failed_decrypt_buf != NULL) kmem_free(failed_decrypt_buf, failed_decrypt_size); failed_decrypt_buf = kmem_alloc(datalen, KM_SLEEP); failed_decrypt_size = datalen; memcpy(failed_decrypt_buf, cipherbuf, datalen); } 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 (SET_ERROR(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 (SET_ERROR(ret)); } #if defined(_KERNEL) && defined(HAVE_SPL) /* 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