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openssh/ssh-keygen.c

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/*
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.
*/
#include "includes.h"
RCSID("$Id: ssh-keygen.c,v 1.3 1999/11/12 04:19:27 damien Exp $");
#include "rsa.h"
#include "ssh.h"
#include "xmalloc.h"
/* Generated private key. */
RSA *private_key;
/* Generated public key. */
RSA *public_key;
/* Number of bits in the RSA key. This value can be changed on the command
line. */
int bits = 1024;
/* Flag indicating that we just want to change the passphrase. This can be
set on the command line. */
int change_passphrase = 0;
/* Flag indicating that we just want to change the comment. This can be set
on the command line. */
int change_comment = 0;
int quiet = 0;
/* This is set to the identity file name if given on the command line. */
char *identity_file = NULL;
/* This is set to the passphrase if given on the command line. */
char *identity_passphrase = NULL;
/* This is set to the new passphrase if given on the command line. */
char *identity_new_passphrase = NULL;
/* This is set to the new comment if given on the command line. */
char *identity_comment = NULL;
/* Perform changing a passphrase. The argument is the passwd structure
for the current user. */
void
do_change_passphrase(struct passwd *pw)
{
char buf[1024], *comment;
char *old_passphrase, *passphrase1, *passphrase2;
struct stat st;
RSA *private_key;
/* Read key file name. */
if (identity_file != NULL) {
strncpy(buf, identity_file, sizeof(buf));
buf[sizeof(buf) - 1] = '\0';
} else {
printf("Enter file in which the key is ($HOME/%s): ", 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. */
public_key = RSA_new();
if (!load_public_key(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_free(public_key);
/* Try to load the file with empty passphrase. */
private_key = RSA_new();
if (!load_private_key(buf, "", private_key, &comment)) {
/* Read passphrase from the user. */
if (identity_passphrase)
old_passphrase = xstrdup(identity_passphrase);
else
old_passphrase = read_passphrase("Enter old passphrase: ", 1);
/* Try to load using the passphrase. */
if (!load_private_key(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("Enter new passphrase (empty for no passphrase): ", 1);
passphrase2 = read_passphrase("Enter 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("Pass phrases do not match. Try again.\n");
exit(1);
}
/* Destroy the other copy. */
memset(passphrase2, 0, strlen(passphrase2));
xfree(passphrase2);
}
/* Save the file using the new passphrase. */
if (!save_private_key(buf, passphrase1, private_key, comment))
{
printf("Saving the key failed: %s: %s.\n",
buf, strerror(errno));
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
RSA_free(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_free(private_key); /* Destroys contents */
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;
RSA *private_key;
char *passphrase;
struct stat st;
FILE *f;
char *tmpbuf;
/* Read key file name. */
if (identity_file)
{
strncpy(buf, identity_file, sizeof(buf));
buf[sizeof(buf) - 1] = '\0';
}
else
{
printf("Enter file in which the key is ($HOME/%s): ",
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. */
public_key = RSA_new();
if (!load_public_key(buf, public_key, NULL))
{
printf("%s is not a valid key file.\n", buf);
exit(1);
}
private_key = RSA_new();
/* Try to load the file with empty passphrase. */
if (load_private_key(buf, "", private_key, &comment))
passphrase = xstrdup("");
else
{
/* 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("Enter passphrase: ", 1);
/* Try to load using the passphrase. */
if (!load_private_key(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_free(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(buf, passphrase, private_key, new_comment))
{
printf("Saving the key failed: %s: %s.\n",
buf, strerror(errno));
memset(passphrase, 0, strlen(passphrase));
xfree(passphrase);
RSA_free(private_key);
xfree(comment);
exit(1);
}
/* Destroy the passphrase and the private key in memory. */
memset(passphrase, 0, strlen(passphrase));
xfree(passphrase);
RSA_free(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 ", BN_num_bits(public_key->n));
tmpbuf = BN_bn2dec(public_key->e);
fprintf(f, "%s ", tmpbuf);
free (tmpbuf);
tmpbuf = BN_bn2dec(public_key->n);
fprintf(f, "%s %s\n", tmpbuf, new_comment);
free (tmpbuf);
fclose(f);
xfree(comment);
printf("The comment in your key file has been changed.\n");
exit(0);
}
/* Main program for key management. */
int
main(int ac, char **av)
{
char buf[16384], buf2[1024], *passphrase1, *passphrase2;
struct passwd *pw;
char *tmpbuf;
int opt;
struct stat st;
FILE *f;
char hostname[MAXHOSTNAMELEN];
extern int optind;
extern char *optarg;
/* check if RSA support exists */
if (rsa_alive() == 0) {
extern char *__progname;
fprintf(stderr,
"%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
__progname);
exit(1);
}
/* 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, "qpcb: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 '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 'q':
quiet = 1;
break;
case '?':
default:
printf("ssh-keygen version %s\n", SSH_VERSION);
printf("Usage: %s [-b bits] [-p] [-c] [-f file] [-P pass] [-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)
{
printf("Can only have one of -p 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);
arc4random_stir();
if (quiet)
rsa_set_verbose(0);
/* Generate the rsa key pair. */
private_key = RSA_new();
public_key = RSA_new();
rsa_generate_key(private_key, public_key, bits);
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 ($HOME/%s): ",
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("Enter passphrase (empty for no passphrase): ", 1);
passphrase2 = read_passphrase("Enter 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);
}
/* Create default commend field for the passphrase. The user can later
edit this field. */
if (identity_comment)
{
strlcpy(buf2, identity_comment, sizeof(buf2));
}
else
{
if (gethostname(hostname, sizeof(hostname)) < 0)
{
perror("gethostname");
exit(1);
}
snprintf(buf2, sizeof buf2, "%s@%s", pw->pw_name, hostname);
}
/* Save the key with the given passphrase and comment. */
if (!save_private_key(buf, passphrase1, private_key, buf2))
{
printf("Saving the key failed: %s: %s.\n",
buf, strerror(errno));
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
goto ask_file_again;
}
/* Clear the passphrase. */
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
/* Clear the private key and the random number generator. */
RSA_free(private_key);
arc4random_stir();
if (!quiet)
printf("Your identification has been saved in %s.\n", buf);
/* Display the public key on the screen. */
if (!quiet) {
printf("Your public key is:\n");
printf("%d ", BN_num_bits(public_key->n));
tmpbuf = BN_bn2dec(public_key->e);
printf("%s ", tmpbuf);
free(tmpbuf);
tmpbuf = BN_bn2dec(public_key->n);
printf("%s %s\n", tmpbuf, buf2);
free(tmpbuf);
}
/* 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 ", BN_num_bits(public_key->n));
tmpbuf = BN_bn2dec(public_key->e);
fprintf(f, "%s ", tmpbuf);
free(tmpbuf);
tmpbuf = BN_bn2dec(public_key->n);
fprintf(f, "%s %s\n", tmpbuf, buf2);
free(tmpbuf);
fclose(f);
if (!quiet)
printf("Your public key has been saved in %s\n", buf);
exit(0);
}
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