crypto_ecc_setup.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2012, 2013, 2015, 2020, 2023 GNUnet e.V.
 
     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.
 
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include <gcrypt.h>
#include "gnunet_util_lib.h"
 
#define LOG(kind, ...) GNUNET_log_from (kind, "util-crypto-ecc", __VA_ARGS__)
 
#define LOG_STRERROR(kind, syscall) \
  GNUNET_log_from_strerror (kind, "util-crypto-ecc", syscall)
 
#define LOG_STRERROR_FILE(kind, syscall, filename) \
  GNUNET_log_from_strerror_file (kind, "util-crypto-ecc", syscall, filename)
 
#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)
 
 
static enum GNUNET_GenericReturnValue
read_from_file (const char *filename,
                void *buf,
                size_t buf_size)
{
  int fd;
  struct stat sb;
 
  fd = open (filename,
             O_RDONLY);
  if (-1 == fd)
  {
    memset (buf,
            0,
            buf_size);
    return GNUNET_SYSERR;
  }
  if (0 != fstat (fd,
                  &sb))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
                              "stat",
                              filename);
    GNUNET_assert (0 == close (fd));
    memset (buf,
            0,
            buf_size);
    return GNUNET_SYSERR;
  }
  if (sb.st_size != buf_size)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "File `%s' has wrong size (%llu), expected %llu bytes\n",
                filename,
                (unsigned long long) sb.st_size,
                (unsigned long long) buf_size);
    GNUNET_assert (0 == close (fd));
    memset (buf,
            0,
            buf_size);
    return GNUNET_SYSERR;
  }
  if (buf_size !=
      read (fd,
            buf,
            buf_size))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
                              "read",
                              filename);
    GNUNET_assert (0 == close (fd));
    memset (buf,
            0,
            buf_size);
    return GNUNET_SYSERR;
  }
  GNUNET_assert (0 == close (fd));
  return GNUNET_OK;
}
 
 
enum GNUNET_GenericReturnValue
GNUNET_CRYPTO_eddsa_key_from_file (const char *filename,
                                   int do_create,
                                   struct GNUNET_CRYPTO_EddsaPrivateKey *pkey)
{
  enum GNUNET_GenericReturnValue ret;
 
  if (GNUNET_OK ==
      read_from_file (filename,
                      pkey,
                      sizeof (*pkey)))
  {
    /* file existed, report that we didn't create it... */
    return (do_create) ? GNUNET_NO : GNUNET_OK;
  }
  else if (! do_create)
  {
    return GNUNET_SYSERR;
  }
 
  GNUNET_CRYPTO_eddsa_key_create (pkey);
  ret = GNUNET_DISK_fn_write (filename,
                              pkey,
                              sizeof (*pkey),
                              GNUNET_DISK_PERM_USER_READ);
  if ( (GNUNET_OK == ret) ||
       (GNUNET_SYSERR == ret) )
    return ret;
  /* maybe another process succeeded in the meantime, try reading one more time */
  if (GNUNET_OK ==
      read_from_file (filename,
                      pkey,
                      sizeof (*pkey)))
  {
    /* file existed, report that *we* didn't create it... */
    return GNUNET_NO;
  }
  /* give up */
  return GNUNET_SYSERR;
}
 
 
enum GNUNET_GenericReturnValue
GNUNET_CRYPTO_ecdsa_key_from_file (const char *filename,
                                   int do_create,
                                   struct GNUNET_CRYPTO_EcdsaPrivateKey *pkey)
{
  if (GNUNET_OK ==
      read_from_file (filename,
                      pkey,
                      sizeof (*pkey)))
  {
    /* file existed, report that we didn't create it... */
    return (do_create) ? GNUNET_NO : GNUNET_OK;
  }
  else if (! do_create)
  {
    return GNUNET_SYSERR;
  }
  GNUNET_CRYPTO_ecdsa_key_create (pkey);
  if (GNUNET_OK ==
      GNUNET_DISK_fn_write (filename,
                            pkey,
                            sizeof (*pkey),
                            GNUNET_DISK_PERM_USER_READ))
    return GNUNET_OK;
  /* maybe another process succeeded in the meantime, try reading one more time */
  if (GNUNET_OK ==
      read_from_file (filename,
                      pkey,
                      sizeof (*pkey)))
  {
    /* file existed, report that *we* didn't create it... */
    return GNUNET_NO;
  }
  /* give up */
  return GNUNET_SYSERR;
}
 
 
struct GNUNET_CRYPTO_EddsaPrivateKey *
GNUNET_CRYPTO_eddsa_key_create_from_configuration (
  const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
  char *fn;
 
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cfg,
                                               "PEER",
                                               "PRIVATE_KEY",
                                               &fn))
    return NULL;
  priv = GNUNET_new (struct GNUNET_CRYPTO_EddsaPrivateKey);
  if (GNUNET_SYSERR == GNUNET_CRYPTO_eddsa_key_from_file (fn,
                                                          GNUNET_YES,
                                                          priv))
  {
    GNUNET_free (fn);
    GNUNET_free (priv);
    return NULL;
  }
  GNUNET_free (fn);
  return priv;
}
 
 
enum GNUNET_GenericReturnValue
GNUNET_CRYPTO_get_peer_identity (const struct GNUNET_CONFIGURATION_Handle *cfg,
                                 struct GNUNET_PeerIdentity *dst)
{
  struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
 
  if (NULL == (priv = GNUNET_CRYPTO_eddsa_key_create_from_configuration (cfg)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("Could not load peer's private key\n"));
    return GNUNET_SYSERR;
  }
  GNUNET_CRYPTO_eddsa_key_get_public (priv,
                                      &dst->public_key);
  GNUNET_free (priv);
  return GNUNET_OK;
}
 
 
enum GNUNET_GenericReturnValue
GNUNET_CRYPTO_sign_by_peer_identity (const struct
                                     GNUNET_CONFIGURATION_Handle *cfg,
                                     const struct
                                     GNUNET_CRYPTO_EccSignaturePurpose *purpose,
                                     struct GNUNET_CRYPTO_EddsaSignature *sig)
{
  struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
  enum GNUNET_GenericReturnValue result;
 
  if (NULL == (priv = GNUNET_CRYPTO_eddsa_key_create_from_configuration (cfg)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("Could not load peer's private key\n"));
    return GNUNET_SYSERR;
  }
 
  result = GNUNET_CRYPTO_eddsa_sign_ (priv, purpose, sig);
  GNUNET_CRYPTO_eddsa_key_clear (priv);
  return result;
}
 
 
enum GNUNET_GenericReturnValue
GNUNET_CRYPTO_verify_peer_identity (uint32_t purpose,
                                    const struct
                                    GNUNET_CRYPTO_EccSignaturePurpose *validate,
                                    const struct
                                    GNUNET_CRYPTO_EddsaSignature *sig,
                                    const struct GNUNET_PeerIdentity *identity)
{
  return GNUNET_CRYPTO_eddsa_verify_ (purpose, validate, sig,
                                      &identity->public_key);
}
 
 
/* end of crypto_ecc_setup.c */