path: root/src/util/crypto_rsa.c

/*
     This file is part of GNUnet.
     (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 2, or (at your
     option) any later version.

     GNUnet 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
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file util/crypto_rsa.c
 * @brief public key cryptography (RSA) with libgcrypt
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gcrypt.h>
#include "gnunet_common.h"
#include "gnunet_util_lib.h"

#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)

#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)

#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util", syscall, filename)

#define HOSTKEY_LEN 2048

#define EXTRA_CHECKS ALLOW_EXTRA_CHECKS


/**
 * The private information of an RSA key pair.
 * NOTE: this must match the definition in crypto_ksk.c and gnunet-rsa.c!
 */
struct GNUNET_CRYPTO_RsaPrivateKey
{
  /**
   * Libgcrypt S-expression for the ECC key.
   */
  gcry_sexp_t sexp;
};

/**
 * Log an error message at log-level 'level' that indicates
 * a failure of the command 'cmd' with the message given
 * by gcry_strerror(rc).
 */
#define LOG_GCRY(level, cmd, rc) do { LOG(level, _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0);

/**
 * If target != size, move target bytes to the
 * end of the size-sized buffer and zero out the
 * first target-size bytes.
 *
 * @param buf original buffer
 * @param size number of bytes in the buffer
 * @param target target size of the buffer
 */
static void
adjust (unsigned char *buf, size_t size, size_t target)
{
  if (size < target)
  {
    memmove (&buf[target - size], buf, size);
    memset (buf, 0, target - size);
  }
}


/**
 * Free memory occupied by RSA private key.
 *
 * @param key pointer to the memory to free
 */
void
GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *key)
{
  gcry_sexp_release (key->sexp);
  GNUNET_free (key);
}


/**
 * Extract values from an S-expression.
 *
 * @param array where to store the result(s)
 * @param sexp S-expression to parse
 * @param topname top-level name in the S-expression that is of interest
 * @param elems names of the elements to extract
 * @return 0 on success
 */
static int
key_from_sexp (gcry_mpi_t * array, gcry_sexp_t sexp, const char *topname,
               const char *elems)
{
  gcry_sexp_t list;
  gcry_sexp_t l2;
  const char *s;
  unsigned int i;
  unsigned int idx;

  if (! (list = gcry_sexp_find_token (sexp, topname, 0)))
    return 1;  
  l2 = gcry_sexp_cadr (list);
  gcry_sexp_release (list);
  list = l2;
  if (! list)  
    return 2;
  idx = 0