// SPDX-License-Identifier: LGPL-2.1-or-later

/*

 * TCRYPT (TrueCrypt-compatible) and VeraCrypt volume handling

 *

 * Copyright (C) 2012-2025 Red Hat, Inc. All rights reserved.

 * Copyright (C) 2012-2025 Milan Broz

 */

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "libcryptsetup.h"

#include "tcrypt.h"

#include "internal.h"

/* TCRYPT PBKDF variants */

static const struct {

  bool legacy;

  bool veracrypt;

  const char *name;

  const char *hash;

  unsigned int iterations;

  uint32_t veracrypt_pim_const;

  uint32_t veracrypt_pim_mult;

} tcrypt_kdf[] = {

  { false, false, "pbkdf2", "ripemd160",   2000, 0, 0 },

  { false, false, "pbkdf2", "ripemd160",   1000, 0, 0 },

  { false, false, "pbkdf2", "sha512",      1000, 0, 0 },

  { false, false, "pbkdf2", "whirlpool",   1000, 0, 0 },

  {  true, false, "pbkdf2", "sha1",        2000, 0, 0 },

  { false,  true, "pbkdf2", "sha512",    500000, 15000, 1000 },

  { false,  true, "pbkdf2", "whirlpool", 500000, 15000, 1000 },

  { false,  true, "pbkdf2", "sha256",    500000, 15000, 1000 }, // VeraCrypt 1.0f

  { false,  true, "pbkdf2", "sha256",    200000,     0, 2048 }, // boot only

  { false,  true, "pbkdf2", "blake2s-256", 500000, 15000, 1000 }, // VeraCrypt 1.26.2

  { false,  true, "pbkdf2", "blake2s-256", 200000,     0, 2048 }, // boot only

  { false,  true, "pbkdf2", "ripemd160", 655331, 15000, 1000 },

  { false,  true, "pbkdf2", "ripemd160", 327661,     0, 2048 }, // boot only

  { false,  true, "pbkdf2", "stribog512",500000, 15000, 1000 },

//  { false,  true, "pbkdf2", "stribog512",200000,     0, 2048 }, // boot only

  { false, false,     NULL,        NULL,      0,     0,    0 }

};

struct tcrypt_alg {

    const char *name;

    unsigned int key_size;

    unsigned int iv_size;

    unsigned int key_offset;

    unsigned int iv_offset; /* or tweak key offset */

    unsigned int key_extra_size;

};

struct tcrypt_algs {

  bool legacy;

  unsigned int chain_count;

  unsigned int chain_key_size;

  const char *long_name;

  const char *mode;

  const struct tcrypt_alg cipher[3];

};

/* TCRYPT cipher variants */

static const struct tcrypt_algs tcrypt_cipher[] = {

/* XTS mode */

{false,1,64,"aes","xts-plain64",

  {{"aes",    64,16,0,32,0}}},

{false,1,64,"serpent","xts-plain64",

  {{"serpent",64,16,0,32,0}}},

{false,1,64,"twofish","xts-plain64",

  {{"twofish",64,16,0,32,0}}},

{false,2,128,"twofish-aes","xts-plain64",

  {{"twofish",64,16, 0,64,0},

   {"aes",    64,16,32,96,0}}},

{false,3,192,"serpent-twofish-aes","xts-plain64",

  {{"serpent",64,16, 0, 96,0},

   {"twofish",64,16,32,128,0},

   {"aes",    64,16,64,160,0}}},

{false,2,128,"aes-serpent","xts-plain64",

  {{"aes",    64,16, 0,64,0},

   {"serpent",64,16,32,96,0}}},

{false,3,192,"aes-twofish-serpent","xts-plain64",

  {{"aes",    64,16, 0, 96,0},

   {"twofish",64,16,32,128,0},

   {"serpent",64,16,64,160,0}}},

{false,2,128,"serpent-twofish","xts-plain64",

  {{"serpent",64,16, 0,64,0},

   {"twofish",64,16,32,96,0}}},

{false,1,64,"camellia","xts-plain64",

  {{"camellia",    64,16,0,32,0}}},

{false,1,64,"kuznyechik","xts-plain64",

  {{"kuznyechik",  64,16,0,32,0}}},

{false,2,128,"kuznyechik-camellia","xts-plain64",

  {{"kuznyechik",64,16, 0,64,0},

   {"camellia",  64,16,32,96,0}}},

{false,2,128,"twofish-kuznyechik","xts-plain64",

  {{"twofish",   64,16, 0,64,0},

   {"kuznyechik",64,16,32,96,0}}},

{false,2,128,"serpent-camellia","xts-plain64",

  {{"serpent",   64,16, 0,64,0},

   {"camellia",  64,16,32,96,0}}},

{false,2,128,"aes-kuznyechik","xts-plain64",

  {{"aes",       64,16, 0,64,0},

   {"kuznyechik",64,16,32,96,0}}},

{false,3,192,"camellia-serpent-kuznyechik","xts-plain64",

  {{"camellia",  64,16, 0, 96,0},

   {"serpent",   64,16,32,128,0},

   {"kuznyechik",64,16,64,160,0}}},

/* LRW mode */

{false,1,48,"aes","lrw-benbi",

  {{"aes",    48,16,32,0,0}}},

{false,1,48,"serpent","lrw-benbi",

  {{"serpent",48,16,32,0,0}}},

{false,1,48,"twofish","lrw-benbi",

  {{"twofish",48,16,32,0,0}}},

{false,2,96,"twofish-aes","lrw-benbi",

  {{"twofish",48,16,32,0,0},

   {"aes",    48,16,64,0,0}}},

{false,3,144,"serpent-twofish-aes","lrw-benbi",

  {{"serpent",48,16,32,0,0},

   {"twofish",48,16,64,0,0},

   {"aes",    48,16,96,0,0}}},

{false,2,96,"aes-serpent","lrw-benbi",

  {{"aes",    48,16,32,0,0},

   {"serpent",48,16,64,0,0}}},

{false,3,144,"aes-twofish-serpent","lrw-benbi",

  {{"aes",    48,16,32,0,0},

   {"twofish",48,16,64,0,0},

   {"serpent",48,16,96,0,0}}},

{false,2,96,"serpent-twofish", "lrw-benbi",

  {{"serpent",48,16,32,0,0},

   {"twofish",48,16,64,0,0}}},

/* Kernel LRW block size is fixed to 16 bytes for GF(2^128)

 * thus cannot be used with blowfish where block is 8 bytes.

 * There also no GF(2^64) support.

{true,1,64,"blowfish_le","lrw-benbi",

   {{"blowfish_le",64,8,32,0,0}}},

{true,2,112,"blowfish_le-aes","lrw-benbi",

   {{"blowfish_le",64, 8,32,0,0},

    {"aes",        48,16,88,0,0}}},

{true,3,160,"serpent-blowfish_le-aes","lrw-benbi",

    {{"serpent",    48,16, 32,0,0},

     {"blowfish_le",64, 8, 64,0,0},

     {"aes",        48,16,120,0,0}}},*/

/*

 * CBC + "outer" CBC (both with whitening)

 * chain_key_size: alg_keys_bytes + IV_seed_bytes + whitening_bytes

 */

{true,1,32+16+16,"aes","cbc-tcw",

  {{"aes",    32,16,32,0,32}}},

{true,1,32+16+16,"serpent","cbc-tcw",

  {{"serpent",32,16,32,0,32}}},

{true,1,32+16+16,"twofish","cbc-tcw",

  {{"twofish",32,16,32,0,32}}},

{true,2,64+16+16,"twofish-aes","cbci-tcrypt",

  {{"twofish",32,16,32,0,0},

   {"aes",    32,16,64,0,32}}},

{true,3,96+16+16,"serpent-twofish-aes","cbci-tcrypt",

  {{"serpent",32,16,32,0,0},

   {"twofish",32,16,64,0,0},

   {"aes",    32,16,96,0,32}}},

{true,2,64+16+16,"aes-serpent","cbci-tcrypt",

  {{"aes",    32,16,32,0,0},

   {"serpent",32,16,64,0,32}}},

{true,3,96+16+16,"aes-twofish-serpent", "cbci-tcrypt",

  {{"aes",    32,16,32,0,0},

   {"twofish",32,16,64,0,0},

   {"serpent",32,16,96,0,32}}},

{true,2,64+16+16,"serpent-twofish", "cbci-tcrypt",

  {{"serpent",32,16,32,0,0},

   {"twofish",32,16,64,0,32}}},

{true,1,16+8+16,"cast5","cbc-tcw",

  {{"cast5",   16,8,32,0,24}}},

{true,1,24+8+16,"des3_ede","cbc-tcw",

  {{"des3_ede",24,8,32,0,24}}},

{true,1,56+8+16,"blowfish_le","cbc-tcrypt",

  {{"blowfish_le",56,8,32,0,24}}},

{true,2,88+16+16,"blowfish_le-aes","cbc-tcrypt",

  {{"blowfish_le",56, 8,32,0,0},

   {"aes",        32,16,88,0,32}}},

{true,3,120+16+16,"serpent-blowfish_le-aes","cbc-tcrypt",

  {{"serpent",    32,16, 32,0,0},

   {"blowfish_le",56, 8, 64,0,0},

   {"aes",        32,16,120,0,32}}},

{}

};

static int TCRYPT_hdr_from_disk(struct crypt_device *cd,

        struct tcrypt_phdr *hdr,

        struct crypt_params_tcrypt *params,

        int kdf_index, int cipher_index)

{

  uint32_t crc32;

  size_t size;

  /* Check CRC32 of header */

  size = TCRYPT_HDR_LEN - sizeof(hdr->d.keys) - sizeof(hdr->d.header_crc32);

  crc32 = crypt_crc32(~0, (unsigned char*)&hdr->d, size) ^ ~0;

  if (be16_to_cpu(hdr->d.version) > 3 &&

      crc32 != be32_to_cpu(hdr->d.header_crc32)) {

    log_dbg(cd, "TCRYPT header CRC32 mismatch.");

    return -EINVAL;

  }

  /* Check CRC32 of keys */

  crc32 = crypt_crc32(~0, (unsigned char*)hdr->d.keys, sizeof(hdr->d.keys)) ^ ~0;

  if (crc32 != be32_to_cpu(hdr->d.keys_crc32)) {

    log_dbg(cd, "TCRYPT keys CRC32 mismatch.");

    return -EINVAL;

  }

  /* Convert header to cpu format */

  hdr->d.version  =  be16_to_cpu(hdr->d.version);

  hdr->d.version_tc = be16_to_cpu(hdr->d.version_tc);

  hdr->d.keys_crc32 = be32_to_cpu(hdr->d.keys_crc32);

  hdr->d.hidden_volume_size = be64_to_cpu(hdr->d.hidden_volume_size);

  hdr->d.volume_size        = be64_to_cpu(hdr->d.volume_size);

  hdr->d.mk_offset = be64_to_cpu(hdr->d.mk_offset);

  if (!hdr->d.mk_offset)

    hdr->d.mk_offset = 512;

  hdr->d.mk_size = be64_to_cpu(hdr->d.mk_size);

  hdr->d.flags = be32_to_cpu(hdr->d.flags);

  hdr->d.sector_size = be32_to_cpu(hdr->d.sector_size);

  if (!hdr->d.sector_size)

    hdr->d.sector_size = 512;

  hdr->d.header_crc32 = be32_to_cpu(hdr->d.header_crc32);

  /* Set params */

  params->passphrase = NULL;

  params->passphrase_size = 0;

  params->hash_name  = tcrypt_kdf[kdf_index].hash;

  params->key_size = tcrypt_cipher[cipher_index].chain_key_size;

  params->cipher = tcrypt_cipher[cipher_index].long_name;

  params->mode = tcrypt_cipher[cipher_index].mode;

  return 0;

}

/*

 * Kernel implements just big-endian version of blowfish, hack it here

 */

static void TCRYPT_swab_le(char *buf)

{

  uint32_t *l = VOIDP_CAST(uint32_t*)&buf[0];

  uint32_t *r = VOIDP_CAST(uint32_t*)&buf[4];

  *l = swab32(*l);

  *r = swab32(*r);

}

static int decrypt_blowfish_le_cbc(const struct tcrypt_alg *alg,

           const char *key, char *buf)

{

  int bs = alg->iv_size;

  char iv[8], iv_old[8];

  struct crypt_cipher *cipher = NULL;

  int i, j, r;

  assert(bs == 8);

  r = crypt_cipher_init(&cipher, "blowfish", "ecb",

            &key[alg->key_offset], alg->key_size);

  if (r < 0)

    return r;

  memcpy(iv, &key[alg->iv_offset], alg->iv_size);

  for (i = 0; i < TCRYPT_HDR_LEN; i += bs) {

    memcpy(iv_old, &buf[i], bs);

    TCRYPT_swab_le(&buf[i]);

    r = crypt_cipher_decrypt(cipher, &buf[i], &buf[i],

            bs, NULL, 0);

    TCRYPT_swab_le(&buf[i]);

    if (r < 0)

      break;

    for (j = 0; j < bs; j++)

      buf[i + j] ^= iv[j];

    memcpy(iv, iv_old, bs);

  }

  crypt_cipher_destroy(cipher);

  crypt_safe_memzero(iv, bs);

  crypt_safe_memzero(iv_old, bs);

  return r;

}

static void TCRYPT_remove_whitening(char *buf, const char *key)

{

  int j;

  for (j = 0; j < TCRYPT_HDR_LEN; j++)

    buf[j] ^= key[j % 8];

}

static void TCRYPT_copy_key(const struct tcrypt_alg *alg, const char *mode,

           char *out_key, const char *key)

{

  int ks2;

  if (!strncmp(mode, "xts", 3)) {

    ks2 = alg->key_size / 2;

    crypt_safe_memcpy(out_key, &key[alg->key_offset], ks2);

    crypt_safe_memcpy(&out_key[ks2], &key[alg->iv_offset], ks2);

  } else if (!strncmp(mode, "lrw", 3)) {

    ks2 = alg->key_size - TCRYPT_LRW_IKEY_LEN;

    crypt_safe_memcpy(out_key, &key[alg->key_offset], ks2);

    crypt_safe_memcpy(&out_key[ks2], key, TCRYPT_LRW_IKEY_LEN);

  } else if (!strncmp(mode, "cbc", 3)) {

    crypt_safe_memcpy(out_key, &key[alg->key_offset], alg->key_size);

    /* IV + whitening */

    crypt_safe_memcpy(&out_key[alg->key_size], &key[alg->iv_offset],

           alg->key_extra_size);

  }

}

static int TCRYPT_decrypt_hdr_one(const struct tcrypt_alg *alg, const char *mode,

           const char *key,struct tcrypt_phdr *hdr)

{

  char backend_key[TCRYPT_HDR_KEY_LEN];

  char iv[TCRYPT_HDR_IV_LEN] = {};

  char mode_name[MAX_CIPHER_LEN + 1];

  struct crypt_cipher *cipher;

  char *c, *buf = (char*)&hdr->e;

  int r;

  /* Remove IV if present */

  mode_name[MAX_CIPHER_LEN] = '\0';

  strncpy(mode_name, mode, MAX_CIPHER_LEN);

  c = strchr(mode_name, '-');

  if (c)

    *c = '\0';

  if (!strncmp(mode, "lrw", 3))

    iv[alg->iv_size - 1] = 1;

  else if (!strncmp(mode, "cbc", 3)) {

    TCRYPT_remove_whitening(buf, &key[8]);

    if (!strcmp(alg->name, "blowfish_le"))

      return decrypt_blowfish_le_cbc(alg, key, buf);

    memcpy(iv, &key[alg->iv_offset], alg->iv_size);

  }

  TCRYPT_copy_key(alg, mode, backend_key, key);

  r = crypt_cipher_init(&cipher, alg->name, mode_name,

            backend_key, alg->key_size);

  if (!r) {

    r = crypt_cipher_decrypt(cipher, buf, buf, TCRYPT_HDR_LEN,

           iv, alg->iv_size);

    crypt_cipher_destroy(cipher);

  }

  crypt_safe_memzero(backend_key, sizeof(backend_key));

  crypt_safe_memzero(iv, TCRYPT_HDR_IV_LEN);

  return r;

}

/*

 * For chained ciphers and CBC mode we need "outer" decryption.

 * Backend doesn't provide this, so implement it here directly using ECB.

 */

static int TCRYPT_decrypt_cbci(const struct tcrypt_algs *ciphers,

        const char *key, struct tcrypt_phdr *hdr)

{

  struct crypt_cipher *cipher[3];

  unsigned int bs = ciphers->cipher[0].iv_size;

  char *buf = (char*)&hdr->e, iv[16], iv_old[16];

  unsigned int i, j;

  int r = -EINVAL;

  assert(ciphers->chain_count <= 3);

  assert(bs <= 16);

  TCRYPT_remove_whitening(buf, &key[8]);

  memcpy(iv, &key[ciphers->cipher[0].iv_offset], bs);

  /* Initialize all ciphers in chain in ECB mode */

  for (j = 0; j < ciphers->chain_count; j++)

    cipher[j] = NULL;

  for (j = 0; j < ciphers->chain_count; j++) {

    r = crypt_cipher_init(&cipher[j], ciphers->cipher[j].name, "ecb",

              &key[ciphers->cipher[j].key_offset],

              ciphers->cipher[j].key_size);

    if (r < 0)

      goto out;

  }

  /* Implements CBC with chained ciphers in loop inside */

  for (i = 0; i < TCRYPT_HDR_LEN; i += bs) {

    memcpy(iv_old, &buf[i], bs);

    for (j = ciphers->chain_count; j > 0; j--) {

      r = crypt_cipher_decrypt(cipher[j - 1], &buf[i], &buf[i],

              bs, NULL, 0);

      if (r < 0)

        goto out;

    }

    for (j = 0; j < bs; j++)

      buf[i + j] ^= iv[j];

    memcpy(iv, iv_old, bs);

  }

out:

  for (j = 0; j < ciphers->chain_count; j++)

    if (cipher[j])

      crypt_cipher_destroy(cipher[j]);

  crypt_safe_memzero(iv, bs);

  crypt_safe_memzero(iv_old, bs);

  return r;

}

static int TCRYPT_decrypt_hdr(struct crypt_device *cd, struct tcrypt_phdr *hdr,

             const char *key, struct crypt_params_tcrypt *params)

{

  struct tcrypt_phdr hdr2;

  int i, j, r = -EINVAL;

  for (i = 0; tcrypt_cipher[i].chain_count; i++) {

    if (params->cipher && !strstr(tcrypt_cipher[i].long_name, params->cipher))

      continue;

    if (!(params->flags & CRYPT_TCRYPT_LEGACY_MODES) && tcrypt_cipher[i].legacy)

      continue;

    log_dbg(cd, "TCRYPT:  trying cipher %s-%s",

      tcrypt_cipher[i].long_name, tcrypt_cipher[i].mode);

    memcpy(&hdr2.e, &hdr->e, TCRYPT_HDR_LEN);

    if (!strncmp(tcrypt_cipher[i].mode, "cbci", 4))

      r = TCRYPT_decrypt_cbci(&tcrypt_cipher[i], key, &hdr2);

    else for (j = tcrypt_cipher[i].chain_count - 1; j >= 0 ; j--) {

      if (!tcrypt_cipher[i].cipher[j].name)

        continue;

      r = TCRYPT_decrypt_hdr_one(&tcrypt_cipher[i].cipher[j],

              tcrypt_cipher[i].mode, key, &hdr2);

      if (r < 0)

        break;

    }

    if (r < 0) {

      log_dbg(cd, "TCRYPT:   returned error %d, skipped.", r);

      if (r == -ENOTSUP)

        break;

      r = -ENOENT;

      continue;

    }

    if (!strncmp(hdr2.d.magic, TCRYPT_HDR_MAGIC, TCRYPT_HDR_MAGIC_LEN)) {

      log_dbg(cd, "TCRYPT: Signature magic detected.");

      memcpy(&hdr->e, &hdr2.e, TCRYPT_HDR_LEN);

      r = i;

      break;

    }

    if ((params->flags & CRYPT_TCRYPT_VERA_MODES) &&

         !strncmp(hdr2.d.magic, VCRYPT_HDR_MAGIC, TCRYPT_HDR_MAGIC_LEN)) {

      log_dbg(cd, "TCRYPT: Signature magic detected (Veracrypt).");

      memcpy(&hdr->e, &hdr2.e, TCRYPT_HDR_LEN);

      r = i;

      break;

    }

    r = -EPERM;

  }

  crypt_safe_memzero(&hdr2, sizeof(hdr2));

  return r;

}

static int TCRYPT_pool_keyfile(struct crypt_device *cd,

        unsigned char pool[VCRYPT_KEY_POOL_LEN],

        const char *keyfile, int keyfiles_pool_length)

{

  unsigned char *data;

  int i, j, fd, data_size, r = -EIO;

  uint32_t crc;

  log_dbg(cd, "TCRYPT: using keyfile %s.", keyfile);

  data = malloc(TCRYPT_KEYFILE_LEN);

  if (!data)

    return -ENOMEM;

  memset(data, 0, TCRYPT_KEYFILE_LEN);

  fd = open(keyfile, O_RDONLY);

  if (fd < 0) {

    log_err(cd, _("Failed to open key file."));

    goto out;

  }

  data_size = read_buffer(fd, data, TCRYPT_KEYFILE_LEN);

  close(fd);

  if (data_size < 0) {

    log_err(cd, _("Error reading keyfile %s."), keyfile);

    goto out;

  }

  for (i = 0, j = 0, crc = ~0U; i < data_size; i++) {

    crc = crypt_crc32(crc, &data[i], 1);

    pool[j++] += (unsigned char)(crc >> 24);

    pool[j++] += (unsigned char)(crc >> 16);

    pool[j++] += (unsigned char)(crc >>  8);

    pool[j++] += (unsigned char)(crc);

    j %= keyfiles_pool_length;

  }

  r = 0;

out:

  crypt_safe_memzero(&crc, sizeof(crc));

  crypt_safe_memzero(data, TCRYPT_KEYFILE_LEN);

  free(data);

  return r;

}

static int TCRYPT_init_hdr(struct crypt_device *cd,

         struct tcrypt_phdr *hdr,

         struct crypt_params_tcrypt *params)

{

  unsigned char pwd[VCRYPT_KEY_POOL_LEN] = {};

  size_t passphrase_size, max_passphrase_size;

  char *key;

  unsigned int i, skipped = 0, iterations;

  int r = -EPERM, keyfiles_pool_length;

  if (posix_memalign((void*)&key, crypt_getpagesize(), TCRYPT_HDR_KEY_LEN))

    return -ENOMEM;

  if (params->flags & CRYPT_TCRYPT_VERA_MODES &&

      params->passphrase_size > TCRYPT_KEY_POOL_LEN) {

    /* Really. Keyfile pool length depends on passphrase size in Veracrypt. */

    max_passphrase_size = VCRYPT_KEY_POOL_LEN;

    keyfiles_pool_length = VCRYPT_KEY_POOL_LEN;

  } else {

    max_passphrase_size = TCRYPT_KEY_POOL_LEN;

    keyfiles_pool_length = TCRYPT_KEY_POOL_LEN;

  }

  if (params->keyfiles_count)

    passphrase_size = max_passphrase_size;

  else

    passphrase_size = params->passphrase_size;

  if (params->passphrase_size > max_passphrase_size) {

    log_err(cd, _("Maximum TCRYPT passphrase length (%zu) exceeded."),

            max_passphrase_size);

    goto out;

  }

  /* Calculate pool content from keyfiles */

  for (i = 0; i < params->keyfiles_count; i++) {

    r = TCRYPT_pool_keyfile(cd, pwd, params->keyfiles[i], keyfiles_pool_length);

    if (r < 0)

      goto out;

  }

  /* If provided password, combine it with pool */

  for (i = 0; i < params->passphrase_size; i++)

    pwd[i] += params->passphrase[i];

  for (i = 0; tcrypt_kdf[i].name; i++) {

    if (params->hash_name && !strstr(tcrypt_kdf[i].hash, params->hash_name))

      continue;

    if (!(params->flags & CRYPT_TCRYPT_LEGACY_MODES) && tcrypt_kdf[i].legacy)

      continue;

    if (!(params->flags & CRYPT_TCRYPT_VERA_MODES) && tcrypt_kdf[i].veracrypt)

      continue;

    if ((params->flags & CRYPT_TCRYPT_VERA_MODES) && params->veracrypt_pim) {

      /* Do not try TrueCrypt modes if we have PIM value */

      if (!tcrypt_kdf[i].veracrypt)

        continue;

      /* adjust iterations to given PIM cmdline parameter */

      iterations = tcrypt_kdf[i].veracrypt_pim_const +

            (tcrypt_kdf[i].veracrypt_pim_mult * params->veracrypt_pim);

    } else

      iterations = tcrypt_kdf[i].iterations;

    /* Derive header key */

    log_dbg(cd, "TCRYPT: trying KDF: %s-%s-%d%s.",

      tcrypt_kdf[i].name, tcrypt_kdf[i].hash, tcrypt_kdf[i].iterations,

      params->veracrypt_pim && tcrypt_kdf[i].veracrypt ? "-PIM" : "");

    r = crypt_pbkdf(tcrypt_kdf[i].name, tcrypt_kdf[i].hash,

        (char*)pwd, passphrase_size,

        hdr->salt, TCRYPT_HDR_SALT_LEN,

        key, TCRYPT_HDR_KEY_LEN,

        iterations, 0, 0);

    if (r < 0) {

      log_verbose(cd, _("PBKDF2 hash algorithm %s not available, skipping."),

              tcrypt_kdf[i].hash);

      skipped++;

      r = -EPERM;

      continue;

    }

    /* Decrypt header */

    r = TCRYPT_decrypt_hdr(cd, hdr, key, params);

    if (r == -ENOENT) {

      skipped++;

      r = -EPERM;

      continue;

    }

    if (r != -EPERM)

      break;

  }

  if ((r < 0 && skipped && skipped == i) || r == -ENOTSUP) {

    log_err(cd, _("Required kernel crypto interface not available."));

#if ENABLE_AF_ALG

    log_err(cd, _("Ensure you have algif_skcipher kernel module loaded."));

#endif

    r = -ENOTSUP;

  }

  if (r < 0)

    goto out;

  r = TCRYPT_hdr_from_disk(cd, hdr, params, i, r);

  if (!r) {

    log_dbg(cd, "TCRYPT: Magic: %s, Header version: %d, req. %d, sector %d"

      ", mk_offset %" PRIu64 ", hidden_size %" PRIu64

      ", volume size %" PRIu64, tcrypt_kdf[i].veracrypt ?

      VCRYPT_HDR_MAGIC : TCRYPT_HDR_MAGIC,

      (int)hdr->d.version, (int)hdr->d.version_tc, (int)hdr->d.sector_size,

      hdr->d.mk_offset, hdr->d.hidden_volume_size, hdr->d.volume_size);

    log_dbg(cd, "TCRYPT: Header cipher %s-%s, key size %zu",

      params->cipher, params->mode, params->key_size);

  }

out:

  crypt_safe_memzero(pwd, TCRYPT_KEY_POOL_LEN);

  if (key)

    crypt_safe_memzero(key, TCRYPT_HDR_KEY_LEN);

  free(key);

  return r;

}

int TCRYPT_read_phdr(struct crypt_device *cd,

         struct tcrypt_phdr *hdr,

         struct crypt_params_tcrypt *params)

{

  struct device *base_device = NULL, *device = crypt_metadata_device(cd);

  ssize_t hdr_size = sizeof(struct tcrypt_phdr);

  char *base_device_path;

  int devfd, r;

  assert(sizeof(struct tcrypt_phdr) == 512);

  log_dbg(cd, "Reading TCRYPT header of size %zu bytes from device %s.",

    hdr_size, device_path(device));

  if (params->flags & CRYPT_TCRYPT_SYSTEM_HEADER &&

      crypt_dev_is_partition(device_path(device))) {

    base_device_path = crypt_get_base_device(device_path(device));

    log_dbg(cd, "Reading TCRYPT system header from device %s.", base_device_path ?: "?");

    if (!base_device_path)

      return -EINVAL;

    r = device_alloc(cd, &base_device, base_device_path);

    free(base_device_path);

    if (r < 0)

      return r;

    devfd = device_open(cd, base_device, O_RDONLY);

  } else

    devfd = device_open(cd, device, O_RDONLY);

  if (devfd < 0) {

    device_free(cd, base_device);

    log_err(cd, _("Cannot open device %s."), device_path(device));

    return -EINVAL;

  }

  r = -EIO;

  if (params->flags & CRYPT_TCRYPT_SYSTEM_HEADER) {

    if (read_lseek_blockwise(devfd, device_block_size(cd, device),

      device_alignment(device), hdr, hdr_size,

      TCRYPT_HDR_SYSTEM_OFFSET) == hdr_size) {

      r = TCRYPT_init_hdr(cd, hdr, params);

    }

  } else if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER) {

    if (params->flags & CRYPT_TCRYPT_BACKUP_HEADER) {

      if (read_lseek_blockwise(devfd, device_block_size(cd, device),

        device_alignment(device), hdr, hdr_size,

        TCRYPT_HDR_HIDDEN_OFFSET_BCK) == hdr_size)

        r = TCRYPT_init_hdr(cd, hdr, params);

    } else {

      if (read_lseek_blockwise(devfd, device_block_size(cd, device),

        device_alignment(device), hdr, hdr_size,

        TCRYPT_HDR_HIDDEN_OFFSET) == hdr_size)

        r = TCRYPT_init_hdr(cd, hdr, params);

      if (r && read_lseek_blockwise(devfd, device_block_size(cd, device),

        device_alignment(device), hdr, hdr_size,

        TCRYPT_HDR_HIDDEN_OFFSET_OLD) == hdr_size)

        r = TCRYPT_init_hdr(cd, hdr, params);

    }

  } else if (params->flags & CRYPT_TCRYPT_BACKUP_HEADER) {

    if (read_lseek_blockwise(devfd, device_block_size(cd, device),

      device_alignment(device), hdr, hdr_size,

      TCRYPT_HDR_OFFSET_BCK) == hdr_size)

      r = TCRYPT_init_hdr(cd, hdr, params);

  } else if (read_lseek_blockwise(devfd, device_block_size(cd, device),

      device_alignment(device), hdr, hdr_size, 0) == hdr_size)

    r = TCRYPT_init_hdr(cd, hdr, params);

  device_free(cd, base_device);

  if (r < 0)

    memset(hdr, 0, sizeof (*hdr));

  return r;

}

static const struct tcrypt_algs *TCRYPT_get_algs(const char *cipher, const char *mode)

{

  int i;

  if (!cipher || !mode)

    return NULL;

  for (i = 0; tcrypt_cipher[i].chain_count; i++)

    if (!strcmp(tcrypt_cipher[i].long_name, cipher) &&

        !strcmp(tcrypt_cipher[i].mode, mode))

        return &tcrypt_cipher[i];

  return NULL;

}

int TCRYPT_activate(struct crypt_device *cd,

         const char *name,

         struct tcrypt_phdr *hdr,

         struct crypt_params_tcrypt *params,

         uint32_t flags)

{

  char dm_name[PATH_MAX], dm_dev_name[PATH_MAX], cipher_spec[MAX_CIPHER_LEN*2+1];

  char *part_path;

  unsigned int i;

  int r;

  uint64_t req_flags, dmc_flags;

  const struct tcrypt_algs *algs;

  enum devcheck device_check;

  uint64_t offset, iv_offset;

  struct volume_key *vk = NULL;

  void *key = NULL;

  struct device  *ptr_dev = crypt_data_device(cd), *device = NULL, *part_device = NULL;

  struct crypt_dm_active_device dmd = {

    .flags = flags

  };

  if (!hdr->d.version) {

    log_dbg(cd, "TCRYPT: this function is not supported without encrypted header load.");

    return -ENOTSUP;

  }

  if (hdr->d.sector_size % SECTOR_SIZE) {

    log_err(cd, _("Activation is not supported for %d sector size."),

      hdr->d.sector_size);

    return -ENOTSUP;

  }

  if (strstr(params->mode, "-tcrypt")) {

    log_err(cd, _("Kernel does not support activation for this TCRYPT legacy mode."));

    return -ENOTSUP;

  }

  if (strstr(params->mode, "-tcw"))

    req_flags = DM_TCW_SUPPORTED;

  else

    req_flags = DM_PLAIN64_SUPPORTED;

  algs = TCRYPT_get_algs(params->cipher, params->mode);

  if (!algs)

    return -EINVAL;

  if (params->flags & CRYPT_TCRYPT_SYSTEM_HEADER)

    dmd.size = 0;

  else if (params->flags & CRYPT_TCRYPT_HIDDEN_HEADER)

    dmd.size = hdr->d.hidden_volume_size / SECTOR_SIZE;

  else

    dmd.size = hdr->d.volume_size / SECTOR_SIZE;

  if (dmd.flags & CRYPT_ACTIVATE_SHARED)

    device_check = DEV_OK;

  else

    device_check = DEV_EXCL;

  offset = crypt_get_data_offset(cd);

  iv_offset = crypt_get_iv_offset(cd);

  /*

   * System encryption is tricky, as the TCRYPT header is outside the partition area.

   * It can be a system partition only (TCRYPT header offset contains MK offset to

   * a particular partition) or the whole system (then MK offset starts on the header itself).

   * IV offset is always partition offset, but device offset depends on whether the user

   * copied the whole disk or just one encrypted partition.

   * This code tries to guess the most common situations but can still fail and use wrong offsets.

   * Recent UEFI systems never use whole system encryption.

   */

  if (params->flags & CRYPT_TCRYPT_SYSTEM_HEADER) {

    if (crypt_dev_is_partition(device_path(crypt_data_device(cd)))) {

      /* One partition */

      offset = 0;

      iv_offset = crypt_dev_partition_offset(device_path(crypt_data_device(cd)));

    } else if (crypt_dev_is_partition(device_path(crypt_metadata_device(cd)))) {

      /* One partition image, header is the original partition */

      offset = 0;

      iv_offset = crypt_dev_partition_offset(device_path(crypt_metadata_device(cd)));

    } else {

      /* No partition info, try partition-only mode searching for partition. */

      part_path = crypt_get_partition_device(device_path(crypt_data_device(cd)),

                     iv_offset, hdr->d.volume_size / SECTOR_SIZE);

      if (!part_path)

        part_path = crypt_get_partition_device(device_path(crypt_metadata_device(cd)),

                       iv_offset, hdr->d.volume_size / SECTOR_SIZE);

      if (part_path) {

        if (!device_alloc(cd, &part_device, part_path)) {

          log_verbose(cd, _("Activating TCRYPT system encryption for partition %s."),

            part_path);

          ptr_dev = part_device;

          offset = 0;

          iv_offset = crypt_dev_partition_offset(part_path);

        }

        free(part_path);

      } else if (device_is_identical(crypt_metadata_device(cd), crypt_data_device(cd))) {

        /*

         * We have no partition offset and TCRYPT system header is on the data device.

         * Use the whole device mapping.

         * There can be active partitions, do not use exclusive flag.

         */

        device_check = DEV_OK;

        dmd.size = hdr->d.volume_size / SECTOR_SIZE;

        log_err(cd, _("Cannot determine TCRYPT system partition offset, activating whole encrypted area."));

      } else {

        /*

         * We have no partition offset and TCRYPT system header is on the metadata device

         * (TCRYPT system header was NOT read from data device).

         * Expect that data device is a copy of partition and not the whole device.

         * This will not work for whole system encryption, though.

         */

        offset = 0;

        log_err(cd, _("Cannot determine TCRYPT system partition offset, activating device as a system partition."));

      }

    }

    log_dbg(cd, "TCRYPT system encryption data_offset %" PRIu64 ", iv_offset %" PRIu64 ".", offset, iv_offset);

  }

  r = device_block_adjust(cd, ptr_dev, device_check,

        offset, &dmd.size, &dmd.flags);

  if (r)

    goto out;

  /* From here, key size for every cipher must be the same */

  vk = crypt_alloc_volume_key(algs->cipher[0].key_size +

            algs->cipher[0].key_extra_size, NULL);

  if (!vk) {

    r = -ENOMEM;

    goto out;

  }

  for (i = algs->chain_count; i > 0; i--) {

    if (i == 1) {

      dm_name[sizeof(dm_name)-1] = '\0';

      strncpy(dm_name, name, sizeof(dm_name)-1);

      dmd.flags = flags;

    } else {

      if (snprintf(dm_name, sizeof(dm_name), "%s_%d", name, i-1) < 0) {

        r = -EINVAL;

        break;

      }

      dmd.flags = flags | CRYPT_ACTIVATE_PRIVATE;

    }

    key = crypt_safe_alloc(crypt_volume_key_length(vk));

    if (!key) {

      r = -ENOMEM;

      break;

    }

    TCRYPT_copy_key(&algs->cipher[i-1], algs->mode,

        key, hdr->d.keys);

    crypt_volume_key_pass_safe_alloc(vk, &key);

    if (algs->chain_count != i) {

      if (snprintf(dm_dev_name, sizeof(dm_dev_name), "%s/%s_%d", dm_get_dir(), name, i) < 0) {

        r = -EINVAL;

        break;

      }

      r = device_alloc(cd, &device, dm_dev_name);

      if (r)

        break;

      ptr_dev = device;