path: root/lib/algorithms/ciphers.c

/*
 * Copyright (C) 2011-2012 Free Software Foundation, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

#include <gnutls_int.h>
#include <algorithms.h>
#include <gnutls_errors.h>
#include <x509/common.h>

struct gnutls_cipher_entry
{
  const char *name;
  gnutls_cipher_algorithm_t id;
  uint16_t blocksize;
  uint16_t keysize;
  unsigned block:1;
  uint16_t iv; /* the size of IV */
  unsigned export_flag:1; /* 0 non export */
  unsigned auth:1; /* Whether it is authenc cipher */
};
typedef struct gnutls_cipher_entry gnutls_cipher_entry;

/* Note that all algorithms are in CBC or STREAM modes. 
 * Do not add any algorithms in other modes (avoid modified algorithms).
 * View first: "The order of encryption and authentication for
 * protecting communications" by Hugo Krawczyk - CRYPTO 2001
 *
 * Make sure to update MAX_CIPHER_BLOCK_SIZE and MAX_CIPHER_KEY_SIZE as well.
 */
static const gnutls_cipher_entry algorithms[] = {
  {"AES-256-CBC", GNUTLS_CIPHER_AES_256_CBC, 16, 32, CIPHER_BLOCK, 16, 0, 0},
  {"AES-192-CBC", GNUTLS_CIPHER_AES_192_CBC, 16, 24, CIPHER_BLOCK, 16, 0, 0},
  {"AES-128-CBC", GNUTLS_CIPHER_AES_128_CBC, 16, 16, CIPHER_BLOCK, 16, 0, 0},
  {"AES-128-GCM", GNUTLS_CIPHER_AES_128_GCM, 16, 16, CIPHER_STREAM, AEAD_IMPLICIT_DATA_SIZE, 0, 1},
  {"AES-256-GCM", GNUTLS_CIPHER_AES_256_GCM, 16, 32, CIPHER_STREAM, AEAD_IMPLICIT_DATA_SIZE, 0, 1},
  {"ARCFOUR-128", GNUTLS_CIPHER_ARCFOUR_128, 1, 16, CIPHER_STREAM, 0, 0, 0},
  {"CAMELLIA-256-CBC", GNUTLS_CIPHER_CAMELLIA_256_CBC, 16, 32, CIPHER_BLOCK,
   16, 0, 0},
  {"CAMELLIA-128-CBC", GNUTLS_CIPHER_CAMELLIA_128_CBC, 16, 16, CIPHER_BLOCK,
   16, 0, 0},
  {"3DES-CBC", GNUTLS_CIPHER_3DES_CBC, 8, 24, CIPHER_BLOCK, 8, 0, 0},
  {"DES-CBC", GNUTLS_CIPHER_DES_CBC, 8, 8, CIPHER_BLOCK, 8, 0, 0},
  {"ARCFOUR-40", GNUTLS_CIPHER_ARCFOUR_40, 1, 5, CIPHER_STREAM, 0, 1, 0},
  {"RC2-40", GNUTLS_CIPHER_RC2_40_CBC, 8, 5, CIPHER_BLOCK, 8, 1, 0},

#ifdef ENABLE_OPENPGP
  {"IDEA-PGP-CFB", GNUTLS_CIPHER_IDEA_PGP_CFB, 8, 16, CIPHER_BLOCK, 8, 0, 0},
  {"3DES-PGP-CFB", GNUTLS_CIPHER_3DES_PGP_CFB, 8, 24, CIPHER_BLOCK, 8, 0, 0},
  {"CAST5-PGP-CFB", GNUTLS_CIPHER_CAST5_PGP_CFB, 8, 16, CIPHER_BLOCK, 8, 0, 0},
  {"BLOWFISH-PGP-CFB", GNUTLS_CIPHER_BLOWFISH_PGP_CFB, 8,
   16 /*actually unlimited */ , CIPHER_BLOCK, 8, 0, 0},
  {"SAFER-SK128-PGP-CFB", GNUTLS_CIPHER_SAFER_SK128_PGP_CFB, 8, 16,
   CIPHER_BLOCK, 8, 0, 0},
  {"AES-128-PGP-CFB", GNUTLS_CIPHER_AES128_PGP_CFB, 16, 16, CIPHER_BLOCK, 16,
   0, 0},
  {"AES-192-PGP-CFB", GNUTLS_CIPHER_AES192_PGP_CFB, 16, 24, CIPHER_BLOCK, 16,
   0, 0},
  {"AES-256-PGP-CFB", GNUTLS_CIPHER_AES256_PGP_CFB, 16, 32, CIPHER_BLOCK, 16,
   0, 0},
  {"TWOFISH-PGP-CFB", GNUTLS_CIPHER_TWOFISH_PGP_CFB, 16, 16, CIPHER_BLOCK, 16,
   0, 0},
#endif
  {"NULL", GNUTLS_CIPHER_NULL, 1, 0, CIPHER_STREAM, 0, 0, 0},
  {0, 0, 0, 0, 0, 0, 0}
};

#define GNUTLS_CIPHER_LOOP(b) \
        const gnutls_cipher_entry *p; \
                for(p = algorithms; p->name != NULL; p++) { b ; }

#define GNUTLS_ALG_LOOP(a) \
                        GNUTLS_CIPHER_LOOP( if(p->id == algorithm) { a; break; } )

/* CIPHER functions */

/**
 * gnutls_cipher_get_block_size:
 * @algorithm: is an encryption algorithm
 *
 * Get block size for encryption algorithm.
 *
 * Returns: block size for encryption algorithm.
 *
 * Since: 2.10.0
 **/
int
gnutls_cipher_get_block_size (gnutls_cipher_algorithm_t algorithm)
{
  size_t ret = 0;
  GNUTLS_ALG_LOOP (ret = p->blocksize);
  return ret;

}

 /* returns the priority */
int
_gnutls_cipher_priority (gnutls_session_t session,
                         gnutls_cipher_algorithm_t algorithm)
{
  unsigned int i;
  for (i = 0; i < session->internals.priorities.cipher.algorithms; i++)
    {
      if (session->internals.priorities.cipher.priority[i] == algorithm)
        return i;
    }
  return -1;
}


int
_gnutls_cipher_is_block (gnutls_cipher_algorithm_t algorithm)
{
  size_t ret = 0;

  GNUTLS_ALG_LOOP (ret = p->block);
  return ret;

}

int
_gnutls_cipher_algo_is_aead (gnutls_cipher_algorithm_t algorithm)
{
  size_t ret = 0;

  GNUTLS_ALG_LOOP (ret = p->auth);
  return ret;

}

/**
 * gnutls_cipher_get_key_size:
 * @algorithm: is an encryption algorithm
 *
 * Get key size for cipher.
 *
 * Returns: length (in bytes) of the given cipher's key size, or 0 if
 *   the given cipher is invalid.
 **/
size_t
gnutls_cipher_get_key_size (gnutls_cipher_algorithm_t algorithm)
{                               /* In bytes */
  size_t ret = 0;
  GNUTLS_ALG_LOOP (ret = p->keysize);
  return ret;

}

int
_gnutls_cipher_get_iv_size (gnutls_cipher_algorithm_t algorithm)
{                               /* In bytes */
  size_t ret = 0;
  GNUTLS_ALG_LOOP (ret = p->iv);
  return ret;

}

int
_gnutls_cipher_get_export_flag (gnutls_cipher_algorithm_t algorithm)
{                               /* In bytes */
  size_t ret = 0;
  GNUTLS_ALG_LOOP (ret = p->export_flag);
  return ret;

}

/**
 * gnutls_cipher_get_name:
 * @algorithm: is an encryption algorithm
 *
 * Convert a #gnutls_cipher_algorithm_t type to a string.
 *
 * Returns: a pointer to a string that contains the name of the
 *   specified cipher, or %NULL.
 **/
const char *
gnutls_cipher_get_name (gnutls_cipher_algorithm_t algorithm)
{
  const char *ret = NULL;

  /* avoid prefix */
  GNUTLS_ALG_LOOP (ret = p->name);

  return ret;
}

/**
 * gnutls_cipher_get_id:
 * @name: is a cipher algorithm name
 *
 * The names are compared in a case insensitive way.
 *
 * Returns: return a #gnutls_cipher_algorithm_t value corresponding to
 *   the specified cipher, or %GNUTLS_CIPHER_UNKNOWN on error.
 **/
gnutls_cipher_algorithm_t
gnutls_cipher_get_id (const char *name)
{
  gnutls_cipher_algorithm_t ret = GNUTLS_CIPHER_UNKNOWN;

  GNUTLS_CIPHER_LOOP (
    if (strcasecmp (p->name, name) == 0) 
      {
        ret = p->id;
        break;
      }
  );

  return ret;
}

/**
 * gnutls_cipher_list:
 *
 * Get a list of supported cipher algorithms.  Note that not
 * necessarily all ciphers are supported as TLS cipher suites.  For
 * example, DES is not supported as a cipher suite, but is supported
 * for other purposes (e.g., PKCS#8 or similar).
 *
 * This function is not thread safe.
 *
 * Returns: a (0)-terminated list of #gnutls_cipher_algorithm_t
 *   integers indicating the available ciphers.
 *
 **/
const gnutls_cipher_algorithm_t *
gnutls_cipher_list (void)
{
static gnutls_cipher_algorithm_t supported_ciphers[MAX_ALGOS] = {0};

  if (supported_ciphers[0] == 0)
    {
      int i = 0;

      GNUTLS_CIPHER_LOOP (
        if (_gnutls_cipher_exists(p->id))
          supported_ciphers[i++]=p->id;
      );
      supported_ciphers[i++]=0;
    }

  return supported_ciphers;
}

int
_gnutls_cipher_is_ok (gnutls_cipher_algorithm_t algorithm)
{
  ssize_t ret = -1;
  GNUTLS_ALG_LOOP (ret = p->id);
  if (ret >= 0)
    ret = 0;
  else
    ret = 1;
  return ret;
}