ssh-add.c

/*

ssh-add.c

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

Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                   All rights reserved

Created: Thu Apr  6 00:52:24 1995 ylo

Adds an identity to the authentication server, or removes an identity.

*/

#include "includes.h"
RCSID("$Id: ssh-add.c,v 1.8 1999/11/15 06:10:57 damien Exp $");

#include "rsa.h"
#include "ssh.h"
#include "xmalloc.h"
#include "authfd.h"

#ifdef USE_EXTERNAL_ASKPASS
int askpass(const char *filename, RSA *key, const char *saved_comment, char **comment);
#endif /* USE_EXTERNAL_ASKPASS */

#ifdef HAVE___PROGNAME
extern char *__progname;
#else /* HAVE___PROGNAME */
const char *__progname = "ssh-add";
#endif /* HAVE___PROGNAME */

void
delete_file(AuthenticationConnection *ac, const char *filename)
{
  RSA *key;
  char *comment;

  key = RSA_new();
  if (!load_public_key(filename, key, &comment))
    {
      printf("Bad key file %s: %s\n", filename, strerror(errno));
      return;
    }

  if (ssh_remove_identity(ac, key))
    fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment);
  else
    fprintf(stderr, "Could not remove identity: %s\n", filename);
  RSA_free(key);
  xfree(comment);
}

void
delete_all(AuthenticationConnection *ac)
{
  /* Send a request to remove all identities. */
  if (ssh_remove_all_identities(ac))
    fprintf(stderr, "All identities removed.\n");
  else
    fprintf(stderr, "Failed to remove all identitities.\n");
}

void
add_file(AuthenticationConnection *ac, const char *filename)
{
  RSA *key;
  RSA *public_key;
  char *saved_comment, *comment;
  int success;
  
  key = RSA_new();
  public_key = RSA_new();
  if (!load_public_key(filename, public_key, &saved_comment))
    {
      printf("Bad key file %s: %s\n", filename, strerror(errno));
      return;
    }
  RSA_free(public_key);

  /* At first, try empty passphrase */
  success = load_private_key(filename, "", key, &comment);
  if (!success) {
    printf("Need passphrase for %s (%s).\n", filename, saved_comment);
    if (!isatty(STDIN_FILENO)) {
#ifdef USE_EXTERNAL_ASKPASS
      int prompts = 3;

      while (prompts && !success)
		{
        success = askpass(filename, key, saved_comment, &comment);
		  prompts--;
		}
		if (!success)
		{
        xfree(saved_comment);
        return;
		}
#else /* !USE_EXTERNAL_ASKPASS */
      xfree(saved_comment);
      return;
#endif /* USE_EXTERNAL_ASKPASS */
    }

    while (!success) {
      char *pass = read_passphrase("Enter passphrase: ", 1);
      if (strcmp(pass, "") == 0){
        xfree(pass);
        xfree(saved_comment);
        return;
      }
      success = load_private_key(filename, pass, key, &comment);
      memset(pass, 0, strlen(pass));
      xfree(pass);
      if (success)
	break;

      printf("Bad passphrase.\n");
    } 
  }
  xfree(saved_comment);

  if (ssh_add_identity(ac, key, comment))
    fprintf(stderr, "Identity added: %s (%s)\n", filename, comment);
  else
    fprintf(stderr, "Could not add identity: %s\n", filename);
  RSA_free(key);
  xfree(comment);
}

void
list_identities(AuthenticationConnection *ac)
{
  BIGNUM *e, *n;
  int bits, status;
  char *comment;
  int had_identities;

  e = BN_new();
  n = BN_new();
  had_identities = 0;
  for (status = ssh_get_first_identity(ac, &bits, e, n, &comment);
       status;
       status = ssh_get_next_identity(ac, &bits, e, n, &comment))
    {
      char *buf;
      had_identities = 1;
      printf("%d ", bits);
      buf = BN_bn2dec(e);
      if (buf != NULL) {
        printf("%s ", buf);
        free (buf);
      } else {
	error("list_identities: BN_bn2dec #1 failed.");
      }
      buf = BN_bn2dec(n);
      if (buf != NULL) {
        printf("%s %s\n", buf, comment);
        free (buf);
      } else {
	error("list_identities: BN_bn2dec #2 failed.");
      }
      xfree(comment);
    }
  BN_clear_free(e);
  BN_clear_free(n);
  if (!had_identities)
    printf("The agent has no identities.\n");
}

int
main(int argc, char **argv)
{
  AuthenticationConnection *ac = NULL;
  struct passwd *pw;
  char buf[1024];
  int no_files = 1;
  int i;
  int deleting = 0;

  /* check if RSA support exists */
  if (rsa_alive() == 0) {

    fprintf(stderr,
      "%s: no RSA support in libssl and libcrypto.  See ssl(8).\n",
      __progname);
    exit(1);
  }

  /* At first, get a connection to the authentication agent. */
  ac = ssh_get_authentication_connection();
  if (ac == NULL) {
    fprintf(stderr, "Could not open a connection to your authentication agent.\n");
    exit(1);
  }

  for (i = 1; i < argc; i++)
    {
      if (strcmp(argv[i], "-l") == 0)
	{
	  list_identities(ac);
	  no_files = 0; /* Don't default-add/delete if -l. */
	  continue;
	}
      if (strcmp(argv[i], "-d") == 0)
	{
	  deleting = 1;
	  continue;
	}
      if (strcmp(argv[i], "-D") == 0)
	{
	  delete_all(ac);
	  no_files = 0;
	  continue;
	}
      no_files = 0;
      if (deleting)
	delete_file(ac, argv[i]);
      else
	add_file(ac, argv[i]);
    }
  if (no_files)
    {
      pw = getpwuid(getuid());
      if (!pw)
	{
	  fprintf(stderr, "No user found with uid %d\n", (int)getuid());
	  ssh_close_authentication_connection(ac);
	  exit(1);
	}
      snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, SSH_CLIENT_IDENTITY);
      if (deleting)
	delete_file(ac, buf);
      else
	add_file(ac, buf);
    }
  ssh_close_authentication_connection(ac);
  exit(0);
}

#ifdef USE_EXTERNAL_ASKPASS
int askpass(const char *filename, RSA *key, const char *saved_comment, char **comment)
{
  int pipes[2];
  char buf[1024];
  int tmp;
  pid_t child;
  FILE *pipef;

  /* Check that we are X11-capable */
  if (getenv("DISPLAY") == NULL)
  	exit(1);

  if (pipe(pipes) == -1) {
    fprintf(stderr, "Creating pipes failed: %s\n", strerror(errno));
    exit(1);
  }

  if (fflush(NULL) == EOF) {
    fprintf(stderr, "Cannot flush buffers: %s\n", strerror(errno));
    exit(1);
  }

  child = fork();
  if (child == -1) {
    fprintf(stderr, "Cannot fork: %s\n", strerror(errno));
    exit(1);
  }
  
  if (child == 0) {
    /* In child */

    close(pipes[0]);
    if (dup2(pipes[1], 1) ==-1) {
      fprintf(stderr, "dup2 failed: %s\n", strerror(errno));
      exit(1);
    }

    tmp = snprintf(buf, sizeof(buf), "Need passphrase for %s (%s)", filename, saved_comment);
    /* skip the prompt if it won't fit */
    if ((tmp < 0) || (tmp >= sizeof(buf)))
      tmp = execlp(ASKPASS_PROGRAM, "ssh-askpass", 0);
    else
      tmp = execlp(ASKPASS_PROGRAM, "ssh-askpass", buf, 0);

    /* Shouldn't get this far */    
    fprintf(stderr, "Executing ssh-askpass failed: %s\n", strerror(errno));
    exit(1);
  } 

  /* In parent */
  close(pipes[1]);

  if ((pipef = fdopen(pipes[0], "r")) == NULL) {
    fprintf(stderr, "fdopen failed: %s\n", strerror(errno));
    exit(1);
  }
  
  /* Read passphrase back from child, abort if none presented */
  if(fgets(buf, sizeof(buf), pipef) == NULL)
    exit(1);

  fclose(pipef);

  if (strchr(buf, '\n'))
    *strchr(buf, '\n') = 0;

  if (waitpid(child, NULL, 0) == -1) {
    fprintf(stderr, "Waiting for child failed: %s\n",
    strerror(errno));
    exit(1);
  }

  /* Try password as it was presented */
  tmp = load_private_key(filename, buf, key, comment);

  memset(buf, 0, sizeof(buf));

  return(tmp);  
}
#endif /* USE_EXTERNAL_ASKPASS */