/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005-2019 Pawel Jakub Dawidek <pawel@dawidek.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _G_ELI_H_
#define _G_ELI_H_

#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <crypto/sha2/sha256.h>
#include <crypto/sha2/sha512.h>
#include <opencrypto/cryptodev.h>
#ifdef _KERNEL
#include <sys/bio.h>
#include <sys/libkern.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <geom/geom.h>
#include <crypto/intake.h>
#else
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#endif
#include <sys/queue.h>
#include <sys/tree.h>
#ifndef _OpenSSL_
#include <sys/md5.h>
#endif

#define G_ELI_CLASS_NAME        "ELI"
#define G_ELI_MAGIC             "GEOM::ELI"
#define G_ELI_SUFFIX            ".eli"

/*
 * Version history:
 * 0 - Initial version number.
 * 1 - Added data authentication support (md_aalgo field and
 *     G_ELI_FLAG_AUTH flag).
 * 2 - Added G_ELI_FLAG_READONLY.
 * 3 - Added 'configure' subcommand.
 * 4 - IV is generated from offset converted to little-endian
 *     (the G_ELI_FLAG_NATIVE_BYTE_ORDER flag will be set for older versions).
 * 5 - Added multiple encrypton keys and AES-XTS support.
 * 6 - Fixed usage of multiple keys for authenticated providers (the
 *     G_ELI_FLAG_FIRST_KEY flag will be set for older versions).
 * 7 - Encryption keys are now generated from the Data Key and not from the
 *     IV Key (the G_ELI_FLAG_ENC_IVKEY flag will be set for older versions).
 */
#define G_ELI_VERSION_00        0
#define G_ELI_VERSION_01        1
#define G_ELI_VERSION_02        2
#define G_ELI_VERSION_03        3
#define G_ELI_VERSION_04        4
#define G_ELI_VERSION_05        5
#define G_ELI_VERSION_06        6
#define G_ELI_VERSION_07        7
#define G_ELI_VERSION           G_ELI_VERSION_07

/* ON DISK FLAGS. */
/* Use random, onetime keys. */
#define G_ELI_FLAG_ONETIME              0x00000001
/* Ask for the passphrase from the kernel, before mounting root. */
#define G_ELI_FLAG_BOOT                 0x00000002
/* Detach on last close, if we were open for writing. */
#define G_ELI_FLAG_WO_DETACH            0x00000004
/* Detach on last close. */
#define G_ELI_FLAG_RW_DETACH            0x00000008
/* Provide data authentication. */
#define G_ELI_FLAG_AUTH                 0x00000010
/* Provider is read-only, we should deny all write attempts. */
#define G_ELI_FLAG_RO                   0x00000020
/* Don't pass through BIO_DELETE requests. */
#define G_ELI_FLAG_NODELETE             0x00000040
/* This GELI supports GELIBoot */
#define G_ELI_FLAG_GELIBOOT             0x00000080
/* Hide passphrase length in GELIboot. */
#define G_ELI_FLAG_GELIDISPLAYPASS      0x00000100
/* Expand provider automatically. */
#define G_ELI_FLAG_AUTORESIZE           0x00000200

/* RUNTIME FLAGS. */
/* Provider was open for writing. */
#define G_ELI_FLAG_WOPEN                0x00010000
/* Destroy device. */
#define G_ELI_FLAG_DESTROY              0x00020000
/* Provider uses native byte-order for IV generation. */
#define G_ELI_FLAG_NATIVE_BYTE_ORDER    0x00040000
/* Provider uses single encryption key. */
#define G_ELI_FLAG_SINGLE_KEY           0x00080000
/* Device suspended. */
#define G_ELI_FLAG_SUSPEND              0x00100000
/* Provider uses first encryption key. */
#define G_ELI_FLAG_FIRST_KEY            0x00200000
/* Provider uses IV-Key for encryption key generation. */
#define G_ELI_FLAG_ENC_IVKEY            0x00400000

/* BIO pflag values. */
#define G_ELI_WORKER(pflags)    ((pflags) & 0xff)
#define G_ELI_MAX_WORKERS       255
#define G_ELI_NEW_BIO           G_ELI_MAX_WORKERS
#define G_ELI_SETWORKER(pflags, w)      \
    (pflags) = ((pflags) & 0xff00) | ((w) & 0xff)
#define G_ELI_SET_NEW_BIO(pflags)       G_ELI_SETWORKER((pflags), G_ELI_NEW_BIO)
#define G_ELI_IS_NEW_BIO(pflags)        (G_ELI_WORKER(pflags) == G_ELI_NEW_BIO)
#define G_ELI_UMA_ALLOC         0x100   /* bio_driver2 alloc came from UMA */

#define SHA512_MDLEN            64
#define G_ELI_AUTH_SECKEYLEN    SHA256_DIGEST_LENGTH

#define G_ELI_MAXMKEYS          2
#define G_ELI_MAXKEYLEN         64
#define G_ELI_USERKEYLEN        G_ELI_MAXKEYLEN
#define G_ELI_DATAKEYLEN        G_ELI_MAXKEYLEN
#define G_ELI_AUTHKEYLEN        G_ELI_MAXKEYLEN
#define G_ELI_IVKEYLEN          G_ELI_MAXKEYLEN
#define G_ELI_SALTLEN           64
#define G_ELI_DATAIVKEYLEN      (G_ELI_DATAKEYLEN + G_ELI_IVKEYLEN)
/* Data-Key, IV-Key, HMAC_SHA512(Derived-Key, Data-Key+IV-Key) */
#define G_ELI_MKEYLEN           (G_ELI_DATAIVKEYLEN + SHA512_MDLEN)
#define G_ELI_OVERWRITES        5
/* Switch data encryption key every 2^20 blocks. */
#define G_ELI_KEY_SHIFT         20

#define G_ELI_CRYPTO_UNKNOWN    0
#define G_ELI_CRYPTO_HW         1
#define G_ELI_CRYPTO_SW         2
#define G_ELI_CRYPTO_SW_ACCEL   3

#ifdef _KERNEL
#if (MAX_KEY_BYTES < G_ELI_DATAIVKEYLEN)
#error "MAX_KEY_BYTES is less than G_ELI_DATAKEYLEN"
#endif

extern int g_eli_debug;
extern u_int g_eli_overwrites;
extern u_int g_eli_batch;

#define G_ELI_DEBUG(lvl, ...) \
    _GEOM_DEBUG("GEOM_ELI", g_eli_debug, (lvl), NULL, __VA_ARGS__)
#define G_ELI_LOGREQ(lvl, bp, ...) \
    _GEOM_DEBUG("GEOM_ELI", g_eli_debug, (lvl), (bp), __VA_ARGS__)

struct g_eli_worker {
        struct g_eli_softc      *w_softc;
        struct proc             *w_proc;
        void                    *w_first_key;
        u_int                    w_number;
        crypto_session_t         w_sid;
        boolean_t                w_active;
        LIST_ENTRY(g_eli_worker) w_next;
};

#endif  /* _KERNEL */

struct g_eli_softc {
        struct g_geom   *sc_geom;
        u_int            sc_version;
        u_int            sc_crypto;
        uint8_t          sc_mkey[G_ELI_DATAIVKEYLEN];
        uint8_t          sc_ekey[G_ELI_DATAKEYLEN];
        TAILQ_HEAD(, g_eli_key) sc_ekeys_queue;
        RB_HEAD(g_eli_key_tree, g_eli_key) sc_ekeys_tree;
#ifndef _STANDALONE
        struct mtx       sc_ekeys_lock;
#endif
        uint64_t         sc_ekeys_total;
        uint64_t         sc_ekeys_allocated;
        u_int            sc_ealgo;
        u_int            sc_ekeylen;
        uint8_t          sc_akey[G_ELI_AUTHKEYLEN];
        u_int            sc_aalgo;
        u_int            sc_akeylen;
        u_int            sc_alen;
        SHA256_CTX       sc_akeyctx;
        uint8_t          sc_ivkey[G_ELI_IVKEYLEN];
        SHA256_CTX       sc_ivctx;
        int              sc_nkey;
        uint32_t         sc_flags;
        int              sc_inflight;
        off_t            sc_mediasize;
        size_t           sc_sectorsize;
        off_t            sc_provsize;
        u_int            sc_bytes_per_sector;
        u_int            sc_data_per_sector;
#ifndef _KERNEL
        int              sc_cpubind;
#else /* _KERNEL */
        boolean_t        sc_cpubind;

        /* Only for software cryptography. */
        struct bio_queue_head sc_queue;
        struct mtx       sc_queue_mtx;
        LIST_HEAD(, g_eli_worker) sc_workers;
#endif /* _KERNEL */
};
#define sc_name          sc_geom->name

#define G_ELI_KEY_MAGIC 0xe11341c

struct g_eli_key {
        /* Key value, must be first in the structure. */
        uint8_t         gek_key[G_ELI_DATAKEYLEN];
        /* Magic. */
        int             gek_magic;
        /* Key number. */
        uint64_t        gek_keyno;
        /* Reference counter. */
        int             gek_count;
        /* Keeps keys sorted by most recent use. */
        TAILQ_ENTRY(g_eli_key) gek_next;
        /* Keeps keys sorted by number. */
        RB_ENTRY(g_eli_key) gek_link;
};

struct g_eli_metadata {
        char            md_magic[16];   /* Magic value. */
        uint32_t        md_version;     /* Version number. */
        uint32_t        md_flags;       /* Additional flags. */
        uint16_t        md_ealgo;       /* Encryption algorithm. */
        uint16_t        md_keylen;      /* Key length. */
        uint16_t        md_aalgo;       /* Authentication algorithm. */
        uint64_t        md_provsize;    /* Provider's size. */
        uint32_t        md_sectorsize;  /* Sector size. */
        uint8_t         md_keys;        /* Available keys. */
        int32_t         md_iterations;  /* Number of iterations for PKCS#5v2. */
        uint8_t         md_salt[G_ELI_SALTLEN]; /* Salt. */
                        /* Encrypted master key (IV-key, Data-key, HMAC). */
        uint8_t         md_mkeys[G_ELI_MAXMKEYS * G_ELI_MKEYLEN];
        u_char          md_hash[16];    /* MD5 hash. */
} __packed;
#ifndef _OpenSSL_
static __inline void
eli_metadata_encode_v0(struct g_eli_metadata *md, u_char **datap)
{
        u_char *p;

        p = *datap;
        le32enc(p, md->md_flags);       p += sizeof(md->md_flags);
        le16enc(p, md->md_ealgo);       p += sizeof(md->md_ealgo);
        le16enc(p, md->md_keylen);      p += sizeof(md->md_keylen);
        le64enc(p, md->md_provsize);    p += sizeof(md->md_provsize);
        le32enc(p, md->md_sectorsize);  p += sizeof(md->md_sectorsize);
        *p = md->md_keys;               p += sizeof(md->md_keys);
        le32enc(p, md->md_iterations);  p += sizeof(md->md_iterations);
        bcopy(md->md_salt, p, sizeof(md->md_salt)); p += sizeof(md->md_salt);
        bcopy(md->md_mkeys, p, sizeof(md->md_mkeys)); p += sizeof(md->md_mkeys);
        *datap = p;
}
static __inline void
eli_metadata_encode_v1v2v3v4v5v6v7(struct g_eli_metadata *md, u_char **datap)
{
        u_char *p;

        p = *datap;
        le32enc(p, md->md_flags);       p += sizeof(md->md_flags);
        le16enc(p, md->md_ealgo);       p += sizeof(md->md_ealgo);
        le16enc(p, md->md_keylen);      p += sizeof(md->md_keylen);
        le16enc(p, md->md_aalgo);       p += sizeof(md->md_aalgo);
        le64enc(p, md->md_provsize);    p += sizeof(md->md_provsize);
        le32enc(p, md->md_sectorsize);  p += sizeof(md->md_sectorsize);
        *p = md->md_keys;               p += sizeof(md->md_keys);
        le32enc(p, md->md_iterations);  p += sizeof(md->md_iterations);
        bcopy(md->md_salt, p, sizeof(md->md_salt)); p += sizeof(md->md_salt);
        bcopy(md->md_mkeys, p, sizeof(md->md_mkeys)); p += sizeof(md->md_mkeys);
        *datap = p;
}
static __inline void
eli_metadata_encode(struct g_eli_metadata *md, u_char *data)
{
        uint32_t hash[4];
        MD5_CTX ctx;
        u_char *p;

        p = data;
        bcopy(md->md_magic, p, sizeof(md->md_magic));
        p += sizeof(md->md_magic);
        le32enc(p, md->md_version);
        p += sizeof(md->md_version);
        switch (md->md_version) {
        case G_ELI_VERSION_00:
                eli_metadata_encode_v0(md, &p);
                break;
        case G_ELI_VERSION_01:
        case G_ELI_VERSION_02:
        case G_ELI_VERSION_03:
        case G_ELI_VERSION_04:
        case G_ELI_VERSION_05:
        case G_ELI_VERSION_06:
        case G_ELI_VERSION_07:
                eli_metadata_encode_v1v2v3v4v5v6v7(md, &p);
                break;
        default:
#ifdef _KERNEL
                panic("%s: Unsupported version %u.", __func__,
                    (u_int)md->md_version);
#else
                assert(!"Unsupported metadata version.");
#endif
        }
        MD5Init(&ctx);
        MD5Update(&ctx, data, p - data);
        MD5Final((void *)hash, &ctx);
        bcopy(hash, md->md_hash, sizeof(md->md_hash));
        bcopy(md->md_hash, p, sizeof(md->md_hash));
}
static __inline int
eli_metadata_decode_v0(const u_char *data, struct g_eli_metadata *md)
{
        uint32_t hash[4];
        MD5_CTX ctx;
        const u_char *p;

        p = data + sizeof(md->md_magic) + sizeof(md->md_version);
        md->md_flags = le32dec(p);      p += sizeof(md->md_flags);
        md->md_ealgo = le16dec(p);      p += sizeof(md->md_ealgo);
        md->md_keylen = le16dec(p);     p += sizeof(md->md_keylen);
        md->md_provsize = le64dec(p);   p += sizeof(md->md_provsize);
        md->md_sectorsize = le32dec(p); p += sizeof(md->md_sectorsize);
        md->md_keys = *p;               p += sizeof(md->md_keys);
        md->md_iterations = le32dec(p); p += sizeof(md->md_iterations);
        bcopy(p, md->md_salt, sizeof(md->md_salt)); p += sizeof(md->md_salt);
        bcopy(p, md->md_mkeys, sizeof(md->md_mkeys)); p += sizeof(md->md_mkeys);
        MD5Init(&ctx);
        MD5Update(&ctx, data, p - data);
        MD5Final((void *)hash, &ctx);
        bcopy(hash, md->md_hash, sizeof(md->md_hash));
        if (bcmp(md->md_hash, p, 16) != 0)
                return (EINVAL);
        return (0);
}

static __inline int
eli_metadata_decode_v1v2v3v4v5v6v7(const u_char *data, struct g_eli_metadata *md)
{
        uint32_t hash[4];
        MD5_CTX ctx;
        const u_char *p;

        p = data + sizeof(md->md_magic) + sizeof(md->md_version);
        md->md_flags = le32dec(p);      p += sizeof(md->md_flags);
        md->md_ealgo = le16dec(p);      p += sizeof(md->md_ealgo);
        md->md_keylen = le16dec(p);     p += sizeof(md->md_keylen);
        md->md_aalgo = le16dec(p);      p += sizeof(md->md_aalgo);
        md->md_provsize = le64dec(p);   p += sizeof(md->md_provsize);
        md->md_sectorsize = le32dec(p); p += sizeof(md->md_sectorsize);
        md->md_keys = *p;               p += sizeof(md->md_keys);
        md->md_iterations = le32dec(p); p += sizeof(md->md_iterations);
        bcopy(p, md->md_salt, sizeof(md->md_salt)); p += sizeof(md->md_salt);
        bcopy(p, md->md_mkeys, sizeof(md->md_mkeys)); p += sizeof(md->md_mkeys);
        MD5Init(&ctx);
        MD5Update(&ctx, data, p - data);
        MD5Final((void *)hash, &ctx);
        bcopy(hash, md->md_hash, sizeof(md->md_hash));
        if (bcmp(md->md_hash, p, 16) != 0)
                return (EINVAL);
        return (0);
}
static __inline int
eli_metadata_decode(const u_char *data, struct g_eli_metadata *md)
{
        int error;

        bcopy(data, md->md_magic, sizeof(md->md_magic));
        if (strcmp(md->md_magic, G_ELI_MAGIC) != 0)
                return (EINVAL);
        md->md_version = le32dec(data + sizeof(md->md_magic));
        switch (md->md_version) {
        case G_ELI_VERSION_00:
                error = eli_metadata_decode_v0(data, md);
                break;
        case G_ELI_VERSION_01:
        case G_ELI_VERSION_02:
        case G_ELI_VERSION_03:
        case G_ELI_VERSION_04:
        case G_ELI_VERSION_05:
        case G_ELI_VERSION_06:
        case G_ELI_VERSION_07:
                error = eli_metadata_decode_v1v2v3v4v5v6v7(data, md);
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return (error);
}
#endif  /* !_OpenSSL */

static __inline u_int
g_eli_str2ealgo(const char *name)
{

        if (strcasecmp("null", name) == 0)
                return (CRYPTO_NULL_CBC);
        else if (strcasecmp("null-cbc", name) == 0)
                return (CRYPTO_NULL_CBC);
        else if (strcasecmp("aes", name) == 0)
                return (CRYPTO_AES_XTS);
        else if (strcasecmp("aes-cbc", name) == 0)
                return (CRYPTO_AES_CBC);
        else if (strcasecmp("aes-xts", name) == 0)
                return (CRYPTO_AES_XTS);
        else if (strcasecmp("camellia", name) == 0)
                return (CRYPTO_CAMELLIA_CBC);
        else if (strcasecmp("camellia-cbc", name) == 0)
                return (CRYPTO_CAMELLIA_CBC);
        return (CRYPTO_ALGORITHM_MIN - 1);
}

static __inline u_int
g_eli_str2aalgo(const char *name)
{

        if (strcasecmp("hmac/sha1", name) == 0)
                return (CRYPTO_SHA1_HMAC);
        else if (strcasecmp("hmac/ripemd160", name) == 0)
                return (CRYPTO_RIPEMD160_HMAC);
        else if (strcasecmp("hmac/sha256", name) == 0)
                return (CRYPTO_SHA2_256_HMAC);
        else if (strcasecmp("hmac/sha384", name) == 0)
                return (CRYPTO_SHA2_384_HMAC);
        else if (strcasecmp("hmac/sha512", name) == 0)
                return (CRYPTO_SHA2_512_HMAC);
        return (CRYPTO_ALGORITHM_MIN - 1);
}

static __inline const char *
g_eli_algo2str(u_int algo)
{

        switch (algo) {
        case CRYPTO_NULL_CBC:
                return ("NULL");
        case CRYPTO_AES_CBC:
                return ("AES-CBC");
        case CRYPTO_AES_XTS:
                return ("AES-XTS");
        case CRYPTO_CAMELLIA_CBC:
                return ("CAMELLIA-CBC");
        case CRYPTO_SHA1_HMAC:
                return ("HMAC/SHA1");
        case CRYPTO_RIPEMD160_HMAC:
                return ("HMAC/RIPEMD160");
        case CRYPTO_SHA2_256_HMAC:
                return ("HMAC/SHA256");
        case CRYPTO_SHA2_384_HMAC:
                return ("HMAC/SHA384");
        case CRYPTO_SHA2_512_HMAC:
                return ("HMAC/SHA512");
        }
        return ("unknown");
}

static __inline void
eli_metadata_dump(const struct g_eli_metadata *md)
{
        static const char hex[] = "0123456789abcdef";
        char str[sizeof(md->md_mkeys) * 2 + 1];
        u_int i;

        printf("     magic: %s\n", md->md_magic);
        printf("   version: %u\n", (u_int)md->md_version);
        printf("     flags: 0x%x\n", (u_int)md->md_flags);
        printf("     ealgo: %s\n", g_eli_algo2str(md->md_ealgo));
        printf("    keylen: %u\n", (u_int)md->md_keylen);
        if (md->md_flags & G_ELI_FLAG_AUTH)
                printf("     aalgo: %s\n", g_eli_algo2str(md->md_aalgo));
        printf("  provsize: %ju\n", (uintmax_t)md->md_provsize);
        printf("sectorsize: %u\n", (u_int)md->md_sectorsize);
        printf("      keys: 0x%02x\n", (u_int)md->md_keys);
        printf("iterations: %d\n", (int)md->md_iterations);
        bzero(str, sizeof(str));
        for (i = 0; i < sizeof(md->md_salt); i++) {
                str[i * 2] = hex[md->md_salt[i] >> 4];
                str[i * 2 + 1] = hex[md->md_salt[i] & 0x0f];
        }
        printf("      Salt: %s\n", str);
        bzero(str, sizeof(str));
        for (i = 0; i < sizeof(md->md_mkeys); i++) {
                str[i * 2] = hex[md->md_mkeys[i] >> 4];
                str[i * 2 + 1] = hex[md->md_mkeys[i] & 0x0f];
        }
        printf("Master Key: %s\n", str);
        bzero(str, sizeof(str));
        for (i = 0; i < 16; i++) {
                str[i * 2] = hex[md->md_hash[i] >> 4];
                str[i * 2 + 1] = hex[md->md_hash[i] & 0x0f];
        }
        printf("  MD5 hash: %s\n", str);
}

#ifdef _KERNEL
static __inline bool
eli_metadata_crypto_supported(const struct g_eli_metadata *md)
{

        switch (md->md_ealgo) {
        case CRYPTO_NULL_CBC:
        case CRYPTO_AES_CBC:
        case CRYPTO_CAMELLIA_CBC:
        case CRYPTO_AES_XTS:
                break;
        default:
                return (false);
        }
        if (md->md_flags & G_ELI_FLAG_AUTH) {
                switch (md->md_aalgo) {
                case CRYPTO_SHA1_HMAC:
                case CRYPTO_RIPEMD160_HMAC:
                case CRYPTO_SHA2_256_HMAC:
                case CRYPTO_SHA2_384_HMAC:
                case CRYPTO_SHA2_512_HMAC:
                        break;
                default:
                        return (false);
                }
        }
        return (true);
}
#endif

static __inline u_int
g_eli_keylen(u_int algo, u_int keylen)
{

        switch (algo) {
        case CRYPTO_NULL_CBC:
                if (keylen == 0)
                        keylen = 64 * 8;
                else {
                        if (keylen > 64 * 8)
                                keylen = 0;
                }
                return (keylen);
        case CRYPTO_AES_CBC:
        case CRYPTO_CAMELLIA_CBC:
                switch (keylen) {
                case 0:
                        return (128);
                case 128:
                case 192:
                case 256:
                        return (keylen);
                default:
                        return (0);
                }
        case CRYPTO_AES_XTS:
                switch (keylen) {
                case 0:
                        return (128);
                case 128:
                case 256:
                        return (keylen);
                default:
                        return (0);
                }
        default:
                return (0);
        }
}

static __inline u_int
g_eli_ivlen(u_int algo)
{

        switch (algo) {
        case CRYPTO_AES_XTS:
                return (AES_XTS_IV_LEN);
        case CRYPTO_AES_CBC:
                return (AES_BLOCK_LEN);
        case CRYPTO_CAMELLIA_CBC:
                return (CAMELLIA_BLOCK_LEN);
        }
        return (0);
}

static __inline u_int
g_eli_hashlen(u_int algo)
{

        switch (algo) {
        case CRYPTO_SHA1_HMAC:
                return (20);
        case CRYPTO_RIPEMD160_HMAC:
                return (20);
        case CRYPTO_SHA2_256_HMAC:
                return (32);
        case CRYPTO_SHA2_384_HMAC:
                return (48);
        case CRYPTO_SHA2_512_HMAC:
                return (64);
        }
        return (0);
}

static __inline off_t
eli_mediasize(const struct g_eli_softc *sc, off_t mediasize, u_int sectorsize)
{

        if ((sc->sc_flags & G_ELI_FLAG_ONETIME) == 0) {
                mediasize -= sectorsize;
        }
        if ((sc->sc_flags & G_ELI_FLAG_AUTH) == 0) {
                mediasize -= (mediasize % sc->sc_sectorsize);
        } else {
                mediasize /= sc->sc_bytes_per_sector;
                mediasize *= sc->sc_sectorsize;
        }

        return (mediasize);
}

static __inline void
eli_metadata_softc(struct g_eli_softc *sc, const struct g_eli_metadata *md,
    u_int sectorsize, off_t mediasize)
{

        sc->sc_version = md->md_version;
        sc->sc_inflight = 0;
        sc->sc_crypto = G_ELI_CRYPTO_UNKNOWN;
        sc->sc_flags = md->md_flags;
        /* Backward compatibility. */
        if (md->md_version < G_ELI_VERSION_04)
                sc->sc_flags |= G_ELI_FLAG_NATIVE_BYTE_ORDER;
        if (md->md_version < G_ELI_VERSION_05)
                sc->sc_flags |= G_ELI_FLAG_SINGLE_KEY;
        if (md->md_version < G_ELI_VERSION_06 &&
            (sc->sc_flags & G_ELI_FLAG_AUTH) != 0) {
                sc->sc_flags |= G_ELI_FLAG_FIRST_KEY;
        }
        if (md->md_version < G_ELI_VERSION_07)
                sc->sc_flags |= G_ELI_FLAG_ENC_IVKEY;
        sc->sc_ealgo = md->md_ealgo;

        if (sc->sc_flags & G_ELI_FLAG_AUTH) {
                sc->sc_akeylen = sizeof(sc->sc_akey) * 8;
                sc->sc_aalgo = md->md_aalgo;
                sc->sc_alen = g_eli_hashlen(sc->sc_aalgo);

                sc->sc_data_per_sector = sectorsize - sc->sc_alen;
                /*
                 * Some hash functions (like SHA1 and RIPEMD160) generates hash
                 * which length is not multiple of 128 bits, but we want data
                 * length to be multiple of 128, so we can encrypt without
                 * padding. The line below rounds down data length to multiple
                 * of 128 bits.
                 */
                sc->sc_data_per_sector -= sc->sc_data_per_sector % 16;

                sc->sc_bytes_per_sector =
                    (md->md_sectorsize - 1) / sc->sc_data_per_sector + 1;
                sc->sc_bytes_per_sector *= sectorsize;
        }
        sc->sc_provsize = mediasize;
        sc->sc_sectorsize = md->md_sectorsize;
        sc->sc_mediasize = eli_mediasize(sc, mediasize, sectorsize);
        sc->sc_ekeylen = md->md_keylen;
}

#ifdef _KERNEL
int g_eli_read_metadata(struct g_class *mp, struct g_provider *pp,
    struct g_eli_metadata *md);
struct g_geom *g_eli_create(struct gctl_req *req, struct g_class *mp,
    struct g_provider *bpp, const struct g_eli_metadata *md,
    const u_char *mkey, int nkey);
int g_eli_destroy(struct g_eli_softc *sc, boolean_t force);

int g_eli_access(struct g_provider *pp, int dr, int dw, int de);
void g_eli_config(struct gctl_req *req, struct g_class *mp, const char *verb);

void g_eli_read_done(struct bio *bp);
void g_eli_write_done(struct bio *bp);
int g_eli_crypto_rerun(struct cryptop *crp);

bool g_eli_alloc_data(struct bio *bp, int sz);
void g_eli_free_data(struct bio *bp);

void g_eli_crypto_read(struct g_eli_softc *sc, struct bio *bp, boolean_t fromworker);
void g_eli_crypto_run(struct g_eli_worker *wr, struct bio *bp);

void g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp);
void g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp);
#endif
void g_eli_crypto_ivgen(struct g_eli_softc *sc, off_t offset, u_char *iv,
    size_t size);

void g_eli_mkey_hmac(unsigned char *mkey, const unsigned char *key);
int g_eli_mkey_decrypt(const struct g_eli_metadata *md,
    const unsigned char *key, unsigned char *mkey, unsigned keyp);
int g_eli_mkey_decrypt_any(const struct g_eli_metadata *md,
    const unsigned char *key, unsigned char *mkey, unsigned *nkeyp);
int g_eli_mkey_encrypt(unsigned algo, const unsigned char *key, unsigned keylen,
    unsigned char *mkey);
#ifdef _KERNEL
void g_eli_mkey_propagate(struct g_eli_softc *sc, const unsigned char *mkey);
#endif

int g_eli_crypto_encrypt(u_int algo, u_char *data, size_t datasize,
    const u_char *key, size_t keysize);
int g_eli_crypto_decrypt(u_int algo, u_char *data, size_t datasize,
    const u_char *key, size_t keysize);

struct hmac_ctx {
        SHA512_CTX      innerctx;
        SHA512_CTX      outerctx;
};

void g_eli_crypto_hmac_init(struct hmac_ctx *ctx, const char *hkey,
    size_t hkeylen);
void g_eli_crypto_hmac_update(struct hmac_ctx *ctx, const uint8_t *data,
    size_t datasize);
void g_eli_crypto_hmac_final(struct hmac_ctx *ctx, uint8_t *md, size_t mdsize);
void g_eli_crypto_hmac(const char *hkey, size_t hkeysize,
    const uint8_t *data, size_t datasize, uint8_t *md, size_t mdsize);

void g_eli_key_fill(struct g_eli_softc *sc, struct g_eli_key *key,
    uint64_t keyno);
#ifdef _KERNEL
void g_eli_key_init(struct g_eli_softc *sc);
void g_eli_key_destroy(struct g_eli_softc *sc);
void g_eli_key_resize(struct g_eli_softc *sc);
uint8_t *g_eli_key_hold(struct g_eli_softc *sc, off_t offset, size_t blocksize);
void g_eli_key_drop(struct g_eli_softc *sc, uint8_t *rawkey);
#endif
#endif  /* !_G_ELI_H_ */