// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * utils_crypt - cipher utilities for cryptsetup

 *

 * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>

 * Copyright (C) 2009-2025 Red Hat, Inc. All rights reserved.

 * Copyright (C) 2009-2025 Milan Broz

 */

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <strings.h>

#include <unistd.h>

#include <ctype.h>

#include <errno.h>

#include "libcryptsetup.h"

#include "utils_crypt.h"

#define MAX_CAPI_LEN_STR "143" /* for sscanf of crypto API string + 16  + \0 */

int crypt_parse_name_and_mode(const char *s, char *cipher, int *key_nums,

            char *cipher_mode)

{

  if (!s || !cipher || !cipher_mode)

    return -EINVAL;

  if (sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]-%" MAX_CIPHER_LEN_STR "s",

       cipher, cipher_mode) == 2) {

    if (!strncmp(cipher, "capi:", 5)) {

      /* CAPI must not use internal cipher driver names with dash */

      if (strchr(cipher_mode, ')'))

        return -EINVAL;

      if (key_nums)

        *key_nums = 1;

      return 0;

    }

    if (!strcmp(cipher_mode, "plain"))

      strcpy(cipher_mode, "cbc-plain");

    if (key_nums) {

      char *tmp = strchr(cipher, ':');

      *key_nums = tmp ? atoi(++tmp) : 1;

      if (!*key_nums)

        return -EINVAL;

    }

    return 0;

  }

  /* Short version for "empty" cipher */

  if (!strcmp(s, "null") || !strcmp(s, "cipher_null")) {

    strcpy(cipher, "cipher_null");

    strcpy(cipher_mode, "ecb");

    if (key_nums)

      *key_nums = 0;

    return 0;

  }

  if (sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]", cipher) == 1) {

    if (!strncmp(cipher, "capi:", 5))

      strcpy(cipher_mode, "");

    else

      strcpy(cipher_mode, "cbc-plain");

    if (key_nums)

      *key_nums = 1;

    return 0;

  }

  return -EINVAL;

}

int crypt_parse_hash_integrity_mode(const char *s, char *integrity)

{

  char mode[MAX_CIPHER_LEN], hash[MAX_CIPHER_LEN];

  int r;

  if (!s || !integrity || strchr(s, '(') || strchr(s, ')'))

    return -EINVAL;

  r = sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]-%" MAX_CIPHER_LEN_STR "s", mode, hash);

  if (r == 2 && !isdigit(hash[0]))

    r = snprintf(integrity, MAX_CIPHER_LEN, "%s(%s)", mode, hash);

  else if (r == 2)

    r = snprintf(integrity, MAX_CIPHER_LEN, "%s-%s", mode, hash);

  else if (r == 1)

    r = snprintf(integrity, MAX_CIPHER_LEN, "%s", mode);

  else

    return -EINVAL;

  if (r < 0 || r >= MAX_CIPHER_LEN)

    return -EINVAL;

  return 0;

}

int crypt_parse_integrity_mode(const char *s, char *integrity,

             int *integrity_key_size, int required_key_size)

{

  int ks = 0, r = 0;

  if (!s || !integrity)

    return -EINVAL;

  /* AEAD modes */

  if (!strcmp(s, "aead") ||

      !strcmp(s, "poly1305") ||

      !strcmp(s, "none")) {

    strncpy(integrity, s, MAX_CIPHER_LEN);

    ks = 0;

    if (required_key_size != ks)

      r = -EINVAL;

  } else if (!strcmp(s, "hmac-sha1")) {

    strncpy(integrity, "hmac(sha1)", MAX_CIPHER_LEN);

    ks = required_key_size ?: 20;

  } else if (!strcmp(s, "hmac-sha256")) {

    strncpy(integrity, "hmac(sha256)", MAX_CIPHER_LEN);

    ks = required_key_size ?: 32;

  } else if (!strcmp(s, "hmac-sha512")) {

    strncpy(integrity, "hmac(sha512)", MAX_CIPHER_LEN);

    ks = required_key_size ?: 64;

  } else if (!strcmp(s, "phmac-sha1")) {

    strncpy(integrity, "phmac(sha1)", MAX_CIPHER_LEN);

    ks = required_key_size;

    if (!required_key_size)

      r = -EINVAL;

  } else if (!strcmp(s, "phmac-sha256")) {

    strncpy(integrity, "phmac(sha256)", MAX_CIPHER_LEN);

    ks = required_key_size;

    if (!required_key_size)

      r = -EINVAL;

  } else if (!strcmp(s, "phmac-sha512")) {

    strncpy(integrity, "phmac(sha512)", MAX_CIPHER_LEN);

    ks = required_key_size;

    if (!required_key_size)

      r = -EINVAL;

  } else if (!strcmp(s, "cmac-aes")) {

    strncpy(integrity, "cmac(aes)", MAX_CIPHER_LEN);

    ks = 16;

    if (required_key_size && required_key_size != ks)

      r = -EINVAL;

  } else

    r = -EINVAL;

  if (integrity_key_size)

    *integrity_key_size = ks;

  return r;

}

int crypt_parse_pbkdf(const char *s, const char **pbkdf)

{

  const char *tmp = NULL;

  if (!s)

    return -EINVAL;

  if (!strcasecmp(s, CRYPT_KDF_PBKDF2))

    tmp = CRYPT_KDF_PBKDF2;

  else if (!strcasecmp(s, CRYPT_KDF_ARGON2I))

    tmp = CRYPT_KDF_ARGON2I;

  else if (!strcasecmp(s, CRYPT_KDF_ARGON2ID))

    tmp = CRYPT_KDF_ARGON2ID;

  if (!tmp)

    return -EINVAL;

  if (pbkdf)

    *pbkdf = tmp;

  return 0;

}

/*

 * Thanks Mikulas Patocka for these two char converting functions.

 *

 * This function is used to load cryptographic keys, so it is coded in such a

 * way that there are no conditions or memory accesses that depend on data.

 *

 * Explanation of the logic:

 * (ch - '9' - 1) is negative if ch <= '9'

 * ('0' - 1 - ch) is negative if ch >= '0'

 * we "and" these two values, so the result is negative if ch is in the range

 * '0' ... '9'

 * we are only interested in the sign, so we do a shift ">> 8"; note that right

 * shift of a negative value is implementation-defined, so we cast the

 * value to (unsigned) before the shift --- we have 0xffffff if ch is in

 * the range '0' ... '9', 0 otherwise

 * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is

 * in the range '0' ... '9', 0 otherwise

 * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'

 * ... '9', -1 otherwise

 * the next line is similar to the previous one, but we need to decode both

 * uppercase and lowercase letters, so we use (ch & 0xdf), which converts

 * lowercase to uppercase

 */

static int hex_to_bin(unsigned char ch)

{

  unsigned char cu = ch & 0xdf;

  return -1 +

    ((ch - '0' +  1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +

    ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);

}

static char hex2asc(unsigned char c)

{

  return c + '0' + ((unsigned)(9 - c) >> 4 & 0x27);

}

ssize_t crypt_hex_to_bytes(const char *hex, char **result, int safe_alloc)

{

  char *bytes;

  size_t i, len;

  int bl, bh;

  if (!hex || !result)

    return -EINVAL;

  len = strlen(hex);

  if (len % 2)

    return -EINVAL;

  len /= 2;

  bytes = safe_alloc ? crypt_safe_alloc(len) : malloc(len);

  if (!bytes)

    return -ENOMEM;

  for (i = 0; i < len; i++) {

    bh = hex_to_bin(hex[i * 2]);

    bl = hex_to_bin(hex[i * 2 + 1]);

    if (bh == -1 || bl == -1) {

      safe_alloc ? crypt_safe_free(bytes) : free(bytes);

      return -EINVAL;

    }

    bytes[i] = (bh << 4) | bl;

  }

  *result = bytes;

  return i;

}

char *crypt_bytes_to_hex(size_t size, const char *bytes)

{

  unsigned i;

  char *hex;

  if (size && !bytes)

    return NULL;

  /* Alloc adds trailing \0 */

  if (size == 0)

    hex = crypt_safe_alloc(2);

  else

    hex = crypt_safe_alloc(size * 2 + 1);

  if (!hex)

    return NULL;

  if (size == 0)

    hex[0] = '-';

  else for (i = 0; i < size; i++) {

    hex[i * 2]     = hex2asc((const unsigned char)bytes[i] >> 4);

    hex[i * 2 + 1] = hex2asc((const unsigned char)bytes[i] & 0xf);

  }

  return hex;

}

void crypt_log_hex(struct crypt_device *cd,

       const char *bytes, size_t size,

       const char *sep, int numwrap, const char *wrapsep)

{

  unsigned i;

  for (i = 0; i < size; i++) {

    if (wrapsep && numwrap && i && !(i % numwrap))

      crypt_logf(cd, CRYPT_LOG_NORMAL, wrapsep);

    crypt_logf(cd, CRYPT_LOG_NORMAL, "%c%c%s",

         hex2asc((const unsigned char)bytes[i] >> 4),

         hex2asc((const unsigned char)bytes[i] & 0xf), sep);

  }

}

bool crypt_is_cipher_null(const char *cipher_spec)

{

  if (!cipher_spec)

    return false;

  return (strstr(cipher_spec, "cipher_null") || !strcmp(cipher_spec, "null"));

}

int crypt_capi_to_cipher(char **org_c, char **org_i, const char *c_dm, const char *i_dm)

{

  char cipher[MAX_CAPI_ONE_LEN], mode[MAX_CAPI_ONE_LEN], iv[MAX_CAPI_ONE_LEN],

       auth[MAX_CAPI_ONE_LEN], tmp[MAX_CAPI_LEN], dmcrypt_tmp[MAX_CAPI_LEN*2],

       capi[MAX_CAPI_LEN+1];

  size_t len;

  int i;

  if (!c_dm)

    return -EINVAL;

  /* legacy mode */

  if (strncmp(c_dm, "capi:", 4)) {

    if (!(*org_c = strdup(c_dm)))

      return -ENOMEM;

    if (i_dm) {

      if (!(*org_i = strdup(i_dm))) {

        free(*org_c);

        *org_c = NULL;

        return -ENOMEM;

      }

    } else

      *org_i = NULL;

    return 0;

  }

  /* modes with capi: prefix */

  i = sscanf(c_dm, "capi:%" MAX_CAPI_LEN_STR "[^-]-%" MAX_CAPI_ONE_LEN_STR "s", tmp, iv);

  if (i != 2)

    return -EINVAL;

  /* non-cryptsetup compatible mode (generic driver with dash?) */

  if (strrchr(iv, ')')) {

    if (i_dm)

      return -EINVAL;

    if (!(*org_c = strdup(c_dm)))

      return -ENOMEM;

    return 0;

  }

  len = strlen(tmp);

  if (len < 2)

    return -EINVAL;

  if (tmp[len-1] == ')')

    tmp[len-1] = '\0';

  if (sscanf(tmp, "rfc4309(%" MAX_CAPI_LEN_STR "s", capi) == 1) {

    if (!(*org_i = strdup("aead")))

      return -ENOMEM;

  } else if (sscanf(tmp, "rfc7539(%" MAX_CAPI_LEN_STR "[^,],%" MAX_CAPI_ONE_LEN_STR "s", capi, auth) == 2) {

    if (!(*org_i = strdup(auth)))

      return -ENOMEM;

  } else if (sscanf(tmp, "authenc(%" MAX_CAPI_ONE_LEN_STR "[^,],%" MAX_CAPI_LEN_STR "s", auth, capi) == 2) {

    if (!(*org_i = strdup(auth)))

      return -ENOMEM;

  } else {

    if (i_dm) {

      if (!(*org_i = strdup(i_dm)))

        return -ENOMEM;

    } else

      *org_i = NULL;

    memset(capi, 0, sizeof(capi));

    strncpy(capi, tmp, sizeof(capi)-1);

  }

  i = sscanf(capi, "%" MAX_CAPI_ONE_LEN_STR "[^(](%" MAX_CAPI_ONE_LEN_STR "[^)])", mode, cipher);

  if (i == 2)

    i = snprintf(dmcrypt_tmp, sizeof(dmcrypt_tmp), "%s-%s-%s", cipher, mode, iv);

  else

    i = snprintf(dmcrypt_tmp, sizeof(dmcrypt_tmp), "%s-%s", capi, iv);

  if (i < 0 || (size_t)i >= sizeof(dmcrypt_tmp)) {

    free(*org_i);

    *org_i = NULL;

    return -EINVAL;

  }

  if (!(*org_c = strdup(dmcrypt_tmp))) {

    free(*org_i);

    *org_i = NULL;

    return -ENOMEM;

  }

  return 0;

}