/*

  silcapputil.c

  Author: Pekka Riikonen <priikone@silcnet.org>

  Copyright (C) 2002 - 2005 Pekka Riikonen

  The contents of this file are subject to one of the Licenses specified 
  in the COPYING file;  You may not use this file except in compliance 
  with the License.

  The software distributed under the License is distributed on an "AS IS"
  basis, in the hope that it will be useful, but WITHOUT WARRANTY OF ANY
  KIND, either expressed or implied.  See the COPYING file for more
  information.

*/
/* $Id: silcapputil.c,v 1.5.2.3 2005/04/22 14:39:59 priikone Exp $ */

#include "silcincludes.h"

static char *silc_create_pk_identifier(void)
{
  char *username = NULL, *realname = NULL;
  char *hostname, email[256];
  char *ident;

  /* Get realname */
  realname = silc_get_real_name();

  /* Get hostname */
  hostname = silc_net_localhost();
  if (!hostname)
    return NULL;

  /* Get username (mandatory) */
  username = silc_get_username();
  if (!username)
    return NULL;

  /* Create default email address, whether it is right or not */
  snprintf(email, sizeof(email), "%s@%s", username, hostname);

  ident = silc_pkcs_encode_identifier(username, hostname, realname, email,
				      NULL, NULL);
  if (realname)
    silc_free(realname);
  silc_free(hostname);
  silc_free(username);

  return ident;
}

/* Generate key pair */

bool silc_create_key_pair(const char *pkcs_name,
			  SilcUInt32 key_len_bits,
			  const char *pub_filename,
			  const char *prv_filename,
			  const char *pub_identifier,
			  const char *passphrase,
			  SilcPKCS *return_pkcs,
			  SilcPublicKey *return_public_key,
			  SilcPrivateKey *return_private_key,
			  bool interactive)
{
  SilcPKCS pkcs;
  SilcPublicKey pub_key;
  SilcPrivateKey prv_key;
  SilcRng rng;
  unsigned char *key;
  SilcUInt32 key_len;
  char line[256];
  char *pkfile = pub_filename ? strdup(pub_filename) : NULL;
  char *prvfile = prv_filename ? strdup(prv_filename) : NULL;
  char *alg = pkcs_name ? strdup(pkcs_name) : NULL;
  char *identifier = pub_identifier ? strdup(pub_identifier) : NULL;
  char *pass = passphrase ? strdup(passphrase) : NULL;

  if (interactive && (!alg || !pub_filename || !prv_filename))
    printf("\
New pair of keys will be created.  Please, answer to following questions.\n\
");

  if (!alg) {
    if (interactive) {
      while (!alg) {
	alg = silc_get_input("PKCS name (l to list names) [rsa]: ", FALSE);
	if (!alg)
	  alg = strdup("rsa");

	if (*alg == 'l' || *alg == 'L') {
	  char *list = silc_pkcs_get_supported();
	  printf("%s\n", list);
	  silc_free(list);
	  silc_free(alg);
	  alg = NULL;
	}
      }
    } else {
      alg = strdup("rsa");
    }
  }

  if (!silc_pkcs_is_supported(alg)) {
    fprintf(stderr, "Unknown PKCS algorithm `%s' or crypto library"
	    "is not initialized", alg);
    return FALSE;
  }

  if (!key_len_bits) {
    if (interactive) {
      char *length = NULL;
      length = silc_get_input("Key length in key_len_bits [2048]: ", FALSE);
      if (length)
	key_len_bits = atoi(length);
      silc_free(length);
    }
    if (!key_len_bits)
      key_len_bits = 2048;
  }

  if (!identifier) {
    char *def = silc_create_pk_identifier();

    if (interactive) {
      memset(line, 0, sizeof(line));
      if (def)
	snprintf(line, sizeof(line), "Identifier [%s]: ", def);
      else
	snprintf(line, sizeof(line),
	       "Identifier (eg. UN=jon, HN=jon.dummy.com, "
	       "RN=Jon Johnson, E=jon@dummy.com): ");

      while (!identifier) {
	identifier = silc_get_input(line, FALSE);
	if (!identifier && def)
	  identifier = strdup(def);
      }
    } else {
      if (!def) {
	fprintf(stderr, "Could not create public key identifier: %s\n",
		strerror(errno));
	return FALSE;
      }
      identifier = strdup(def);
    }

    silc_free(def);
  }

  rng = silc_rng_alloc();
  silc_rng_init(rng);
  silc_rng_global_init(rng);

  if (!pkfile) {
    if (interactive) {
      memset(line, 0, sizeof(line));
      snprintf(line, sizeof(line), "Public key filename [public_key.pub]: ");
      pkfile = silc_get_input(line, FALSE);
    }
    if (!pkfile)
      pkfile = strdup("public_key.pub");
  }

  if (!prvfile) {
    if (interactive) {
      memset(line, 0, sizeof(line));
      snprintf(line, sizeof(line), "Private key filename [private_key.prv]: ");
      prvfile = silc_get_input(line, FALSE);
    }
    if (!prvfile)
      prvfile = strdup("private_key.prv");
  }

  if (!pass) {
    while (TRUE) {
      char *pass2 = NULL;
      pass = silc_get_input("Private key passphrase: ", TRUE);
      if (!pass) {
        pass = strdup("");
	break;
      } else {
	bool match;
	printf("\n");
	pass2 = silc_get_input("Retype private key passphrase: ", TRUE);
	if (!pass2)
	  pass2 = strdup("");
	match = !strcmp(pass, pass2);
	silc_free(pass2);
	if (match)
	  break;
	fprintf(stderr, "\nPassphrases do not match\n\n");
      }
    }
  }

  /* Generate keys */
  silc_pkcs_alloc(alg, &pkcs);
  silc_pkcs_generate_key(pkcs, key_len_bits, rng);

  /* Save public key into file */
  key = silc_pkcs_get_public_key(pkcs, &key_len);
  pub_key = silc_pkcs_public_key_alloc(silc_pkcs_get_name(pkcs),
				       identifier, key, key_len);
  silc_pkcs_save_public_key(pkfile, pub_key, SILC_PKCS_FILE_PEM);
  if (return_public_key)
    *return_public_key = pub_key;
  else
    silc_pkcs_public_key_free(pub_key);
  memset(key, 0, key_len);
  silc_free(key);

  /* Save private key into file */
  key = silc_pkcs_get_private_key(pkcs, &key_len);
  prv_key = silc_pkcs_private_key_alloc(silc_pkcs_get_name(pkcs),
					key, key_len);
  silc_pkcs_save_private_key(prvfile, prv_key,
			     (unsigned char *)pass, strlen(pass),
			     SILC_PKCS_FILE_BIN);
  if (return_private_key)
    *return_private_key = prv_key;
  else
    silc_pkcs_private_key_free(prv_key);
  memset(key, 0, key_len);
  silc_free(key);

  printf("Public key has been saved into `%s'.\n", pkfile);
  printf("Private key has been saved into `%s'.\n", prvfile);
  if (interactive) {
    printf("Press <Enter> to continue...\n");
    getchar();
  }

  if (return_pkcs)
    *return_pkcs = pkcs;
  else
    silc_pkcs_free(pkcs);

  silc_rng_free(rng);
  silc_free(alg);
  silc_free(pkfile);
  silc_free(prvfile);
  silc_free(identifier);
  memset(pass, 0, strlen(pass));
  silc_free(pass);

  return TRUE;
}

/* Load key pair */

bool silc_load_key_pair(const char *pub_filename,
			const char *prv_filename,
			const char *passphrase,
			SilcPKCS *return_pkcs,
			SilcPublicKey *return_public_key,
			SilcPrivateKey *return_private_key)
{
  char *pass = passphrase ? strdup(passphrase) : NULL;

  SILC_LOG_DEBUG(("Loading public and private keys"));

  if (silc_pkcs_load_public_key((char *)pub_filename, return_public_key,
				SILC_PKCS_FILE_PEM) == FALSE)
    if (silc_pkcs_load_public_key((char *)pub_filename, return_public_key,
				  SILC_PKCS_FILE_BIN) == FALSE) {
      if (pass)
	memset(pass, 0, strlen(pass));
      silc_free(pass);
      return FALSE;
    }

  if (!pass) {
    pass = silc_get_input("Private key passphrase: ", TRUE);
    if (!pass)
      pass = strdup("");
  }

  if (silc_pkcs_load_private_key((char *)prv_filename, return_private_key,
				 (unsigned char *)pass, strlen(pass),
				 SILC_PKCS_FILE_BIN) == FALSE)
    if (silc_pkcs_load_private_key((char *)prv_filename, return_private_key,
				   (unsigned char *)pass, strlen(pass),
				   SILC_PKCS_FILE_PEM) == FALSE) {
      memset(pass, 0, strlen(pass));
      silc_free(pass);
      return FALSE;
    }

  if (return_pkcs) {
    silc_pkcs_alloc((*return_public_key)->name, return_pkcs);
    silc_pkcs_public_key_set(*return_pkcs, *return_public_key);
    silc_pkcs_private_key_set(*return_pkcs, *return_private_key);
  }

  memset(pass, 0, strlen(pass));
  silc_free(pass);
  return TRUE;
}

/* Dump public key into stdout */

bool silc_show_public_key(const char *pub_filename)
{
  SilcPublicKey public_key;
  SilcPublicKeyIdentifier ident;
  char *fingerprint, *babbleprint;
  unsigned char *pk;
  SilcUInt32 pk_len;
  SilcPKCS pkcs;
  SilcUInt32 key_len = 0;

  if (silc_pkcs_load_public_key((char *)pub_filename, &public_key,
				SILC_PKCS_FILE_PEM) == FALSE)
    if (silc_pkcs_load_public_key((char *)pub_filename, &public_key,
				  SILC_PKCS_FILE_BIN) == FALSE) {
      fprintf(stderr, "Could not load public key file `%s'\n", pub_filename);
      return FALSE;
    }

  ident = silc_pkcs_decode_identifier(public_key->identifier);

  pk = silc_pkcs_public_key_encode(public_key, &pk_len);
  fingerprint = silc_hash_fingerprint(NULL, pk, pk_len);
  babbleprint = silc_hash_babbleprint(NULL, pk, pk_len);

  if (silc_pkcs_alloc(public_key->name, &pkcs)) {
    key_len = silc_pkcs_public_key_set(pkcs, public_key);
    silc_pkcs_free(pkcs);
  }

  printf("Public key file    : %s\n", pub_filename);
  printf("Algorithm          : %s\n", public_key->name);
  if (key_len)
    printf("Key length (bits)  : %d\n", (unsigned int)key_len);
  if (ident->realname)
    printf("Real name          : %s\n", ident->realname);
  if (ident->username)
    printf("Username           : %s\n", ident->username);
  if (ident->host)
    printf("Hostname           : %s\n", ident->host);
  if (ident->email)
    printf("Email              : %s\n", ident->email);
  if (ident->org)
    printf("Organization       : %s\n", ident->org);
  if (ident->country)
    printf("Country            : %s\n", ident->country);
  printf("Fingerprint (SHA1) : %s\n", fingerprint);
  printf("Babbleprint (SHA1) : %s\n", babbleprint);

  fflush(stdout);

  silc_free(fingerprint);
  silc_free(babbleprint);
  silc_free(pk);
  silc_pkcs_public_key_free(public_key);
  silc_pkcs_free_identifier(ident);

  return TRUE;
}

/* Change private key passphrase */

bool silc_change_private_key_passphrase(const char *prv_filename,
					const char *old_passphrase,
					const char *new_passphrase)
{
  SilcPrivateKey private_key;
  bool base64 = FALSE;
  char *pass;

  pass = old_passphrase ? strdup(old_passphrase) : NULL;
  if (!pass) {
    pass = silc_get_input("Old passphrase: ", TRUE);
    if (!pass)
      pass = strdup("");
  }

  if (silc_pkcs_load_private_key((char *)prv_filename, &private_key,
				 (unsigned char *)pass, strlen(pass),
				 SILC_PKCS_FILE_BIN) == FALSE) {
    base64 = TRUE;
    if (silc_pkcs_load_private_key((char *)prv_filename, &private_key,
				   (unsigned char *)pass, strlen(pass),
				   SILC_PKCS_FILE_PEM) == FALSE) {
      memset(pass, 0, strlen(pass));
      silc_free(pass);
      fprintf(stderr, "Could not load private key `%s' file\n", prv_filename);
      return FALSE;
    }
  }

  memset(pass, 0, strlen(pass));
  silc_free(pass);

  pass = new_passphrase ? strdup(new_passphrase) : NULL;
  if (!pass) {
    char *pass2 = NULL;
    fprintf(stdout, "\n");
    pass = silc_get_input("New passphrase: ", TRUE);
    if (!pass) {
      pass = strdup("");
    } else {
      while (TRUE) {
	printf("\n");
	pass2 = silc_get_input("Retype new passphrase: ", TRUE);
	if (!pass2)
	  pass2 = strdup("");
	if (!strcmp(pass, pass2))
	  break;
	fprintf(stderr, "\nPassphrases do not match");
      }
      silc_free(pass2);
    }
  }

  silc_pkcs_save_private_key((char *)prv_filename, private_key,
			     (unsigned char *)pass, strlen(pass),
			     base64 ? SILC_PKCS_FILE_PEM : SILC_PKCS_FILE_BIN);

  fprintf(stdout, "\nPassphrase changed\n");

  memset(pass, 0, strlen(pass));
  silc_free(pass);

  silc_pkcs_private_key_free(private_key);
  return TRUE;
}