/*

ssh-keygen.c

Author: Tatu Ylonen <ylo@cs.hut.fi>

Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                   All rights reserved

Created: Mon Mar 27 02:26:40 1995 ylo

Identity and host key generation and maintenance.

*/

/*
 * $Id: ssh-keygen.c,v 1.13 1999/02/21 19:52:44 ylo Exp $
 * $Log: ssh-keygen.c,v $
 * Revision 1.13  1999/02/21 19:52:44  ylo
 * 	Intermediate commit of ssh1.2.27 stuff.
 * 	Main change is sprintf -> snprintf; however, there are also
 * 	many other changes.
 *
 * Revision 1.12  1998/05/23 20:37:28  kivinen
 *      Changed () -> (void).
 *
 * Revision 1.11  1997/04/27  21:54:52  kivinen
 *      Added F-SECURE stuff.
 *
 * Revision 1.10  1997/04/17 04:17:35  kivinen
 *      Removed extra variables.
 *
 * Revision 1.9  1997/04/05 21:59:56  kivinen
 *      Added checks that userfile_get_des_1_magic_phrase succeeded
 *      before using passphrase.
 *
 * Revision 1.8  1997/03/25 05:46:26  kivinen
 *      Fixed bug in SECURE_RPC code.
 *
 * Revision 1.7  1997/03/19 17:42:58  kivinen
 *      Added SECURE_RPC, SECURE_NFS and NIS_PLUS support from Andy
 *      Polyakov <appro@fy.chalmers.se>.
 *
 * Revision 1.6  1996/11/09 17:29:22  ttsalo
 *       Modified ssh-keygen to tell pw->pw_dir instead of '/u/ttsalo'
 *
 * Revision 1.5  1996/10/03 16:59:41  ttsalo
 *      Small fix in option-parsing
 *
 * Revision 1.4  1996/10/03 16:54:58  ttsalo
 *      New feature: updating the keyfiles' cipher type.
 *
 * Revision 1.3  1996/08/06 07:55:15  ylo
 *      Don't advertise the possibility of using an empty passphrase.
 *
 * Revision 1.2  1996/05/30 16:39:07  ylo
 *      Don't loop forever if -f given, and saving fails.
 *
 * Revision 1.1.1.1  1996/02/18 21:38:12  ylo
 *      Imported ssh-1.2.13.
 *
 * Revision 1.5  1995/08/31  09:22:50  ylo
 *      Use either passphrase when only one needed.
 *
 * Revision 1.4  1995/08/29  22:33:00  ylo
 *      Added support for -P, -N, -f, and -C.
 *
 * Revision 1.3  1995/07/26  17:11:31  ylo
 *      Print version number in the usage string.
 *
 * Revision 1.2  1995/07/13  01:39:53  ylo
 *      Removed "Last modified" header.
 *      Added cvs log.
 *
 * $Endlog$
 */

#include "includes.h"
#ifndef HAVE_GETHOSTNAME
#include <sys/utsname.h>
#endif
#include "randoms.h"
#include "rsa.h"
#include "ssh.h"
#include "xmalloc.h"
#include "userfile.h"

/* Generated private key. */
RSAPrivateKey private_key;

/* Generated public key. */
RSAPublicKey public_key;

/* Random number generator state. */
RandomState state;

/* Number of bits in the RSA key.  This value can be changed on the command
   line. */
int bits = 1024;

/* Flag indicating that we just want to change the passphrase.  This can be
   set on the command line. */
int change_passphrase = 0;

/* Flag indicating that we just want to change the comment.  This can be set
   on the command line. */
int change_comment = 0;

/* Flag indicating that we want to change cipher type to default in ssh.h */
int update_cipher = 0;

/* This is set to the identity file name if given on the command line. */
char *identity_file = NULL;

/* This is set to the passphrase if given on the command line. */
char *identity_passphrase = NULL;

/* This is set to the new passphrase if given on the command line. */
char *identity_new_passphrase = NULL;

/* This is set to the new comment if given on the command line. */
char *identity_comment = NULL;

/* Perform changing a passphrase.  The argument is the passwd structure
   for the current user. */

void do_change_passphrase(struct passwd *pw)
{
  char buf[1024], *comment;
  RSAPrivateKey private_key;
  char *old_passphrase, *passphrase1, *passphrase2;
  struct stat st;
  int done;

  /* Read key file name. */
  if (identity_file != NULL)
    {
      strncpy(buf, identity_file, sizeof(buf));
      buf[sizeof(buf) - 1] = '\0';
    }
  else
    {
      printf("Enter file key is in (%s/%s): ",
             pw->pw_dir, SSH_CLIENT_IDENTITY);
      fflush(stdout);
      if (fgets(buf, sizeof(buf), stdin) == NULL)
        exit(1);
      if (strchr(buf, '\n'))
        *strchr(buf, '\n') = 0;
      if (strcmp(buf, "") == 0)
        snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_CLIENT_IDENTITY);
    }

  /* Check if the file exists. */
  if (stat(buf, &st) < 0)
    {
      perror(buf);
      exit(1);
    }
  
  /* Try to load the public key from the file the verify that it is
     readable and of the proper format. */
  if (!load_public_key(geteuid(), buf, &public_key, NULL))
    {
      printf("%s is not a valid key file.\n", buf);
      exit(1);
    }
  /* Clear the public key since we are just about to load the whole file. */
  rsa_clear_public_key(&public_key);

  /* Try to load the file with empty passphrase. */
  done = load_private_key(geteuid(), buf, "", &private_key, &comment);
  
#ifdef SECURE_RPC
  if (!done)
    {
      old_passphrase = userfile_get_des_1_magic_phrase(geteuid());
      if (old_passphrase != NULL)
        {
          done = load_private_key(geteuid(), buf, old_passphrase,
                                  &private_key, &comment);
          if (done)
            printf ("Using SUN-DES-1 magic phrase to decrypt the private key.\n");
          memset(old_passphrase, 0, strlen(old_passphrase));
          xfree(old_passphrase);
          old_passphrase = NULL;
        }
    }
#endif
  if (!done)
    {
      /* Read passphrase from the user. */
      if (identity_passphrase)
        old_passphrase = xstrdup(identity_passphrase);
      else
        old_passphrase = read_passphrase(geteuid(), 
                                         "Enter old passphrase: ", 1);
      /* Try to load using the passphrase. */
      if (!load_private_key(geteuid(), buf, old_passphrase, &private_key, 
                            &comment))
        {
          memset(old_passphrase, 0, strlen(old_passphrase));
          xfree(old_passphrase);
          printf("Bad passphrase.\n");
          exit(1);
        }
      /* Destroy the passphrase. */
      memset(old_passphrase, 0, strlen(old_passphrase));
      xfree(old_passphrase);
    }
  printf("Key has comment '%s'\n", comment);
  
  /* Ask the new passphrase (twice). */
  if (identity_new_passphrase)
    {
      passphrase1 = xstrdup(identity_new_passphrase);
      passphrase2 = NULL;
    }
  else
    {
      passphrase1 = 
        read_passphrase(geteuid(),
                        "Enter new passphrase: ", 1);
      passphrase2 = read_passphrase(geteuid(), 
                                    "Enter the same passphrase again: ", 1);

      /* Verify that they are the same. */
      if (strcmp(passphrase1, passphrase2) != 0)
        {
          memset(passphrase1, 0, strlen(passphrase1));
          memset(passphrase2, 0, strlen(passphrase2));
          xfree(passphrase1);
          xfree(passphrase2);
          printf("Passphrases do not match.  Try again.\n");
          exit(1);
        }
      /* Destroy the other copy. */
      memset(passphrase2, 0, strlen(passphrase2));
      xfree(passphrase2);
    }

#ifdef SECURE_RPC
  if (!strcmp (passphrase1,"SUN-DES-1"))
    {
      memset(passphrase1, 0, strlen(passphrase1));
      xfree(passphrase1);
      passphrase1 = userfile_get_des_1_magic_phrase(geteuid());
      if (passphrase1 == NULL)
        {
          printf ("Failed to get SUN-DES-1 magic phrase. Run keylogin.\n");
          exit (1);
        }
      printf ("Using SUN-DES-1 magic phrase to encrypt the private key.\n");
    }
#endif
  /* Save the file using the new passphrase. */
  if (!save_private_key(geteuid(), buf, passphrase1, &private_key, comment, 
                        &state))
    {
      printf("Saving the key failed: %s: %s.\n",
             buf, strerror(errno));
      memset(passphrase1, 0, strlen(passphrase1));
      xfree(passphrase1);
      rsa_clear_private_key(&private_key);
      xfree(comment);
      exit(1);
    }
  /* Destroy the passphrase and the copy of the key in memory. */
  memset(passphrase1, 0, strlen(passphrase1));
  xfree(passphrase1);
  rsa_clear_private_key(&private_key);
  xfree(comment);

  printf("Your identification has been saved with the new passphrase.\n");
  exit(0);
}

/* Change the comment of a private key file. */

void do_change_comment(struct passwd *pw)
{
  char buf[1024], new_comment[1024], *comment;
  RSAPrivateKey private_key;
  char *passphrase = NULL;
  struct stat st;
  FILE *f;

  /* Read key file name. */
  if (identity_file)
    {
      strncpy(buf, identity_file, sizeof(buf));
      buf[sizeof(buf) - 1] = '\0';
    }
  else
    {
      printf("Enter file key is in (%s/%s): ",
             pw->pw_dir, SSH_CLIENT_IDENTITY);
      fflush(stdout);
      if (fgets(buf, sizeof(buf), stdin) == NULL)
        exit(1);
      if (strchr(buf, '\n'))
        *strchr(buf, '\n') = 0;
      if (strcmp(buf, "") == 0)
        snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_CLIENT_IDENTITY);
    }

  /* Check if the file exists. */
  if (stat(buf, &st) < 0)
    {
      perror(buf);
      exit(1);
    }
  
  /* Try to load the public key from the file the verify that it is
     readable and of the proper format. */
  if (!load_public_key(geteuid(), buf, &public_key, NULL))
    {
      printf("%s is not a valid key file.\n", buf);
      exit(1);
    }

  /* Try to load the file with empty passphrase. */
  if (load_private_key(geteuid(), buf, "", &private_key, &comment))
    passphrase = xstrdup("");
#ifdef SECURE_RPC
  if (passphrase == NULL)
    {
      passphrase = userfile_get_des_1_magic_phrase(geteuid());
      if (passphrase != NULL)
        {
          if (load_private_key(geteuid(), buf, passphrase,
                               &private_key, &comment))
            printf ("Using SUN-DES-1 magic phrase to decrypt the private key.\n");
          else
            {
              memset(passphrase, 0, strlen(passphrase));
              xfree(passphrase);
              passphrase = NULL;
            }
        }
    }
#endif
  if (passphrase == NULL)
    {
      /* Read passphrase from the user. */
      if (identity_passphrase)
        passphrase = xstrdup(identity_passphrase);
      else
        if (identity_new_passphrase)
          passphrase = xstrdup(identity_new_passphrase);
        else
          passphrase = read_passphrase(geteuid(), "Enter passphrase: ", 1);
      /* Try to load using the passphrase. */
      if (!load_private_key(geteuid(), buf, passphrase, &private_key, 
                            &comment))
        {
          memset(passphrase, 0, strlen(passphrase));
          xfree(passphrase);
          printf("Bad passphrase.\n");
          exit(1);
        }
    }
  printf("Key now has comment '%s'\n", comment);

  if (identity_comment)
    {
      strncpy(new_comment, identity_comment, sizeof(new_comment));
      new_comment[sizeof(new_comment) - 1] = '\0';
    }
  else
    {
      printf("Enter new comment: ");
      fflush(stdout);
      if (!fgets(new_comment, sizeof(new_comment), stdin))
        {
          memset(passphrase, 0, strlen(passphrase));
          rsa_clear_private_key(&private_key);
          exit(1);
        }
      
      /* Remove terminating newline from comment. */
      if (strchr(new_comment, '\n'))
        *strchr(new_comment, '\n') = 0;
    }
      
  /* Save the file using the new passphrase. */
  if (!save_private_key(geteuid(), buf, passphrase, &private_key, new_comment, 
                        &state))
    {
      printf("Saving the key failed: %s: %s.\n",
             buf, strerror(errno));
      memset(passphrase, 0, strlen(passphrase));
      xfree(passphrase);
      rsa_clear_private_key(&private_key);
      xfree(comment);
      exit(1);
    }

  /* Destroy the passphrase and the private key in memory. */
  memset(passphrase, 0, strlen(passphrase));
  xfree(passphrase);
  rsa_clear_private_key(&private_key);

  /* Save the public key in text format in a file with the same name but
     .pub appended. */
  strcat(buf, ".pub");
  f = fopen(buf, "w");
  if (!f)
    {
      printf("Could not save your public key in %s\n", buf);
      exit(1);
    }
  fprintf(f, "%d ", public_key.bits);
  mpz_out_str(f, 10, &public_key.e);
  fprintf(f, " ");
  mpz_out_str(f, 10, &public_key.n);
  fprintf(f, " %s\n", new_comment);
  fclose(f);

  xfree(comment);

  printf("The comment in your key file has been changed.\n");
  exit(0);
}

void do_update_cipher(struct passwd *pw)
{
  char buf[1024], *comment;
  RSAPrivateKey private_key;
  char *passphrase = NULL;
  struct stat st;

  /* Read key file name. */
  if (identity_file)
    {
      strncpy(buf, identity_file, sizeof(buf));
      buf[sizeof(buf) - 1] = '\0';
    }
  else
    {
      printf("Enter file key is in (%s/%s): ",
             pw->pw_dir, SSH_CLIENT_IDENTITY);
      fflush(stdout);
      if (fgets(buf, sizeof(buf), stdin) == NULL)
        exit(1);
      if (strchr(buf, '\n'))
        *strchr(buf, '\n') = 0;
      if (strcmp(buf, "") == 0)
        snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_CLIENT_IDENTITY);
    }

  /* Check if the file exists. */
  if (stat(buf, &st) < 0)
    {
      perror(buf);
      exit(1);
    }
  
  /* Try to load the file with empty passphrase. */
  if (load_private_key(geteuid(), buf, "", &private_key, &comment))
    passphrase = xstrdup("");
#ifdef SECURE_RPC
  if (passphrase == NULL)
    {
      passphrase = userfile_get_des_1_magic_phrase(geteuid());
      if (passphrase != NULL)
        {
          if (load_private_key(geteuid(), buf, passphrase,
                               &private_key, &comment))
            printf ("Using SUN-DES-1 magic phrase to decrypt the private key.\n");
          else
            {
              memset(passphrase, 0, strlen(passphrase));
              xfree(passphrase);
              passphrase = NULL;
            }
        }
    }
#endif 
  if (passphrase == NULL)
    {
      /* Read passphrase from the user. */
      if (identity_passphrase)
        passphrase = xstrdup(identity_passphrase);
      else
        if (identity_new_passphrase)
          passphrase = xstrdup(identity_new_passphrase);
        else
          passphrase = read_passphrase(geteuid(), "Enter passphrase: ", 1);
      /* Try to load using the passphrase. */
      if (!load_private_key(geteuid(), buf, passphrase, &private_key, 
                            &comment))
        {
          memset(passphrase, 0, strlen(passphrase));
          xfree(passphrase);
          printf("Bad passphrase.\n");
          exit(1);
        }
    }

  /* Save the file, using SSH_AUTHFILE_CIPHER (defined in ssh.h) */
  if (!save_private_key(geteuid(), buf, passphrase, &private_key, comment, 
                        &state))
    {
      printf("Saving the key failed: %s: %s.\n",
             buf, strerror(errno));
      memset(passphrase, 0, strlen(passphrase));
      xfree(passphrase);
      rsa_clear_private_key(&private_key);
      xfree(comment);
      exit(1);
    }

  /* Destroy the passphrase and the private key in memory. */
  memset(passphrase, 0, strlen(passphrase));
  xfree(passphrase);
  rsa_clear_private_key(&private_key);

  xfree(comment);

  printf("Key's cipher has been updated.\n");
  exit(0);
}
  
/* Main program for key management. */

int main(int ac, char **av)
{
  char buf[16384], buf2[1024], *passphrase1, *passphrase2;
  struct passwd *pw;
  int opt;
  struct stat st;
  FILE *f;
#ifdef HAVE_GETHOSTNAME
  char hostname[257];
#else
  struct utsname uts;
#endif
  extern int optind;
  extern char *optarg;

  /* Get user\'s passwd structure.  We need this for the home directory. */
  pw = getpwuid(getuid());
  if (!pw)
    {
      printf("You don't exist, go away!\n");
      exit(1);
    }

  /* Create ~/.ssh directory if it doesn\'t already exist. */
  snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_USER_DIR);
  if (stat(buf, &st) < 0)
    if (mkdir(buf, 0755) < 0)
      error("Could not create directory '%s'.", buf);

  /* Parse command line arguments. */
  while ((opt = getopt(ac, av, "pcub:f:P:N:C:")) != EOF)
    {
      switch (opt)
        {
        case 'b':
          bits = atoi(optarg);
          if (bits < 512 || bits > 32768)
            {
              printf("Bits has bad value.\n");
              exit(1);
            }
          break;

        case 'p':
          change_passphrase = 1;
          break;

        case 'c':
          change_comment = 1;
          break;

        case 'u':
          update_cipher = 1;
          break;

        case 'f':
          identity_file = optarg;
          break;
          
        case 'P':
          identity_passphrase = optarg;
          break;

        case 'N':
          identity_new_passphrase = optarg;
          break;

        case 'C':
          identity_comment = optarg;
          break;

        case '?':
        default:
#ifdef F_SECURE_COMMERCIAL

#endif /* F_SECURE_COMMERCIAL */
          printf("ssh-keygen version %s\n", SSH_VERSION);
          printf("Usage: %s [-b bits] [-p] [-c] [-u] [-f file] [-P pass]\n"
                 "          [-N new-pass] [-C comment]\n", av[0]);
          exit(1);
        }
    }
  if (optind < ac)
    {
      printf("Too many arguments.\n");
      exit(1);
    }
  if (change_passphrase + change_comment + update_cipher > 1)
    {
      printf("Can only have one of -p, -u and -c.\n");
      exit(1);
    }

  /* If the user requested to change the passphrase, do it now.  This
     function never returns. */
  if (change_passphrase)
    do_change_passphrase(pw);

  /* If the user requested to change the comment, do it now.  This function
     never returns. */
  if (change_comment)
    do_change_comment(pw);

  /* If the user requested to update the cipher, do it now.  This function
     never returns. */
  if (update_cipher)
    do_update_cipher(pw);
  
  /* Initialize random number generator.  This may take a while if the
     user has no seed file, so display a message to the user. */
  printf("Initializing random number generator...\n");
  snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_CLIENT_SEEDFILE);
  random_initialize(&state, geteuid(), buf);

  /* Save random seed so we don't need to do all that time-consuming
     environmental noise collection the next time. */
  random_save(&state, geteuid(), buf);

  /* Generate the rsa key pair. */
  rsa_generate_key(&private_key, &public_key, &state, bits);

  /* Save the state again, just to remove any fear that the previous state
     could be used to recreate the key.  (That should not be possible anyway
     since the pool is stirred after save and some noise is added.) */
  random_save(&state, geteuid(), buf);

 ask_file_again:

  /* Ask for a file to save the key in. */
  if (identity_file)
    {
      strncpy(buf, identity_file, sizeof(buf));
      buf[sizeof(buf) - 1] = '\0';
    }
  else
    {
      printf("Enter file in which to save the key (%s/%s): ",
             pw->pw_dir, SSH_CLIENT_IDENTITY);
      fflush(stdout);
      if (fgets(buf, sizeof(buf), stdin) == NULL)
        exit(1);
      if (strchr(buf, '\n'))
        *strchr(buf, '\n') = 0;
      if (strcmp(buf, "") == 0)
        snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, SSH_CLIENT_IDENTITY);
    }

  /* If the file aready exists, ask the user to confirm. */
  if (stat(buf, &st) >= 0)
    {
      printf("%s already exists.\n", buf);
      printf("Overwrite (y/n)? ");
      fflush(stdout);
      if (fgets(buf2, sizeof(buf2), stdin) == NULL)
        exit(1);
      if (buf2[0] != 'y' && buf2[0] != 'Y')
        exit(1);
    }
  
  /* Ask for a passphrase (twice). */
  if (identity_passphrase)
    passphrase1 = xstrdup(identity_passphrase);
  else
    if (identity_new_passphrase)
      passphrase1 = xstrdup(identity_new_passphrase);
    else
      {
      passphrase_again:
        passphrase1 = 
          read_passphrase(geteuid(), 
                          "Enter passphrase: ", 1);
        passphrase2 = read_passphrase(geteuid(),
                                      "Enter the same passphrase again: ", 1);
        if (strcmp(passphrase1, passphrase2) != 0)
          {
            /* The passphrases do not match.  Clear them and retry. */
            memset(passphrase1, 0, strlen(passphrase1));
            memset(passphrase2, 0, strlen(passphrase2));
            xfree(passphrase1);
            xfree(passphrase2);
            printf("Passphrases do not match.  Try again.\n");
            goto passphrase_again;
          }
        /* Clear the other copy of the passphrase. */
        memset(passphrase2, 0, strlen(passphrase2));
        xfree(passphrase2);
      }
  
#ifdef SECURE_RPC
  if (!strcmp (passphrase1,"SUN-DES-1"))
    {
      memset(passphrase1, 0, strlen(passphrase1));
      xfree(passphrase1);
      passphrase1 = userfile_get_des_1_magic_phrase(geteuid());
      if (passphrase1 == NULL)
        {
          printf ("Failed to get SUN-DES-1 magic phrase. Run keylogin.\n");
          exit (1);
        }
      printf ("Using SUN-DES-1 magic phrase to encrypt the private key.\n");
    }
#endif

  /* Create default commend field for the passphrase.  The user can later
     edit this field. */
  if (identity_comment)
    {
      strncpy(buf2, identity_comment, sizeof(buf2));
      buf2[sizeof(buf2) - 1] = '\0';
    }
  else
    {
#ifdef HAVE_GETHOSTNAME
      if (gethostname(hostname, sizeof(hostname)) < 0)
        {
          perror("gethostname");
          exit(1);
        }
      snprintf(buf2, sizeof(buf2), "%s@%s", pw->pw_name, hostname);
#else
      if (uname(&uts) < 0)
        {
          perror("uname");
          exit(1);
        }
      snprintf(buf2, sizeof(buf2), "%s@%s", pw->pw_name, uts.nodename);
#endif
    }

  /* Save the key with the given passphrase and comment. */
  if (!save_private_key(geteuid(), buf, passphrase1, &private_key, buf2, 
                        &state))
    {
      printf("Saving the key failed: %s: %s.\n",
             buf, strerror(errno));
      memset(passphrase1, 0, strlen(passphrase1));
      xfree(passphrase1);
      if (identity_file) /* Supplied on the command line. */
        exit(1);
      goto ask_file_again;
    }
  /* Clear the passphrase. */
  memset(passphrase1, 0, strlen(passphrase1));
  xfree(passphrase1);

  /* Clear the private key and the random number generator. */
  rsa_clear_private_key(&private_key);
  random_clear(&state);

  printf("Your identification has been saved in %s.\n", buf);

  /* Display the public key on the screen. */
  printf("Your public key is:\n");
  printf("%d ", public_key.bits);
  mpz_out_str(stdout, 10, &public_key.e);
  printf(" ");
  mpz_out_str(stdout, 10, &public_key.n);
  printf(" %s\n", buf2);

  /* Save the public key in text format in a file with the same name but
     .pub appended. */
  strcat(buf, ".pub");
  f = fopen(buf, "w");
  if (!f)
    {
      printf("Could not save your public key in %s\n", buf);
      exit(1);
    }
  fprintf(f, "%d ", public_key.bits);
  mpz_out_str(f, 10, &public_key.e);
  fprintf(f, " ");
  mpz_out_str(f, 10, &public_key.n);
  fprintf(f, " %s\n", buf2);
  fclose(f);

  printf("Your public key has been saved in %s\n", buf);
  
  exit(0);
}