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openssh/ssh-keygen.c

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/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Identity and host key generation and maintenance.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#include "includes.h"
RCSID("$OpenBSD: ssh-keygen.c,v 1.32 2000/10/09 21:30:44 markus Exp $");
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include "ssh.h"
#include "xmalloc.h"
#include "key.h"
#include "rsa.h"
#include "dsa.h"
#include "authfile.h"
#include "uuencode.h"
#include "buffer.h"
#include "bufaux.h"
/* Number of bits in the RSA/DSA 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;
/* Flag indicating that we just want to see the key fingerprint */
int print_fingerprint = 0;
/* The identity file name, given on the command line or entered by the user. */
char identity_file[1024];
int have_identity = 0;
/* 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;
/* Dump public key file in format used by real and the original SSH 2 */
int convert_to_ssh2 = 0;
int convert_from_ssh2 = 0;
int print_public = 0;
int dsa_mode = 0;
/* argv0 */
#ifdef HAVE___PROGNAME
extern char *__progname;
#else /* HAVE___PROGNAME */
static const char *__progname = "ssh-keygen";
#endif /* HAVE___PROGNAME */
char hostname[MAXHOSTNAMELEN];
void
ask_filename(struct passwd *pw, const char *prompt)
{
char buf[1024];
snprintf(identity_file, sizeof(identity_file), "%s/%s",
pw->pw_dir,
dsa_mode ? SSH_CLIENT_ID_DSA: SSH_CLIENT_IDENTITY);
printf("%s (%s): ", prompt, identity_file);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
exit(1);
if (strchr(buf, '\n'))
*strchr(buf, '\n') = 0;
if (strcmp(buf, "") != 0)
strlcpy(identity_file, buf, sizeof(identity_file));
have_identity = 1;
}
int
try_load_key(char *filename, Key *k)
{
int success = 1;
if (!load_private_key(filename, "", k, NULL)) {
char *pass = read_passphrase("Enter passphrase: ", 1);
if (!load_private_key(filename, pass, k, NULL)) {
success = 0;
}
memset(pass, 0, strlen(pass));
xfree(pass);
}
return success;
}
#define SSH_COM_PUBLIC_BEGIN "---- BEGIN SSH2 PUBLIC KEY ----"
#define SSH_COM_PUBLIC_END "---- END SSH2 PUBLIC KEY ----"
#define SSH_COM_PRIVATE_BEGIN "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----"
#define SSH_COM_PRIVATE_KEY_MAGIC 0x3f6ff9eb
void
do_convert_to_ssh2(struct passwd *pw)
{
Key *k;
int len;
unsigned char *blob;
struct stat st;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
k = key_new(KEY_DSA);
if (!try_load_key(identity_file, k)) {
fprintf(stderr, "load failed\n");
exit(1);
}
dsa_make_key_blob(k, &blob, &len);
fprintf(stdout, "%s\n", SSH_COM_PUBLIC_BEGIN);
fprintf(stdout,
"Comment: \"%d-bit %s, converted from OpenSSH by %s@%s\"\n",
key_size(k), key_type(k),
pw->pw_name, hostname);
dump_base64(stdout, blob, len);
fprintf(stdout, "%s\n", SSH_COM_PUBLIC_END);
key_free(k);
xfree(blob);
exit(0);
}
void
buffer_get_bignum_bits(Buffer *b, BIGNUM *value)
{
int bits = buffer_get_int(b);
int bytes = (bits + 7) / 8;
if (buffer_len(b) < bytes)
fatal("buffer_get_bignum_bits: input buffer too small");
BN_bin2bn((unsigned char *)buffer_ptr(b), bytes, value);
buffer_consume(b, bytes);
}
Key *
do_convert_private_ssh2_from_blob(char *blob, int blen)
{
Buffer b;
DSA *dsa;
Key *key = NULL;
int ignore, magic, rlen;
char *type, *cipher;
buffer_init(&b);
buffer_append(&b, blob, blen);
magic = buffer_get_int(&b);
if (magic != SSH_COM_PRIVATE_KEY_MAGIC) {
error("bad magic 0x%x != 0x%x", magic, SSH_COM_PRIVATE_KEY_MAGIC);
buffer_free(&b);
return NULL;
}
ignore = buffer_get_int(&b);
type = buffer_get_string(&b, NULL);
cipher = buffer_get_string(&b, NULL);
ignore = buffer_get_int(&b);
ignore = buffer_get_int(&b);
ignore = buffer_get_int(&b);
xfree(type);
if (strcmp(cipher, "none") != 0) {
error("unsupported cipher %s", cipher);
xfree(cipher);
buffer_free(&b);
return NULL;
}
xfree(cipher);
key = key_new(KEY_DSA);
dsa = key->dsa;
dsa->priv_key = BN_new();
if (dsa->priv_key == NULL) {
error("alloc priv_key failed");
key_free(key);
return NULL;
}
buffer_get_bignum_bits(&b, dsa->p);
buffer_get_bignum_bits(&b, dsa->g);
buffer_get_bignum_bits(&b, dsa->q);
buffer_get_bignum_bits(&b, dsa->pub_key);
buffer_get_bignum_bits(&b, dsa->priv_key);
rlen = buffer_len(&b);
if(rlen != 0)
error("do_convert_private_ssh2_from_blob: remaining bytes in key blob %d", rlen);
buffer_free(&b);
return key;
}
void
do_convert_from_ssh2(struct passwd *pw)
{
Key *k;
int blen;
char line[1024], *p;
char blob[8096];
char encoded[8096];
struct stat st;
int escaped = 0, private = 0, ok;
FILE *fp;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
fp = fopen(identity_file, "r");
if (fp == NULL) {
perror(identity_file);
exit(1);
}
encoded[0] = '\0';
while (fgets(line, sizeof(line), fp)) {
if (!(p = strchr(line, '\n'))) {
fprintf(stderr, "input line too long.\n");
exit(1);
}
if (p > line && p[-1] == '\\')
escaped++;
if (strncmp(line, "----", 4) == 0 ||
strstr(line, ": ") != NULL) {
if (strstr(line, SSH_COM_PRIVATE_BEGIN) != NULL)
private = 1;
fprintf(stderr, "ignore: %s", line);
continue;
}
if (escaped) {
escaped--;
fprintf(stderr, "escaped: %s", line);
continue;
}
*p = '\0';
strlcat(encoded, line, sizeof(encoded));
}
blen = uudecode(encoded, (unsigned char *)blob, sizeof(blob));
if (blen < 0) {
fprintf(stderr, "uudecode failed.\n");
exit(1);
}
k = private ?
do_convert_private_ssh2_from_blob(blob, blen) :
dsa_key_from_blob(blob, blen);
if (k == NULL) {
fprintf(stderr, "decode blob failed.\n");
exit(1);
}
ok = private ?
PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
key_write(k, stdout);
if (!ok) {
fprintf(stderr, "key write failed");
exit(1);
}
key_free(k);
fprintf(stdout, "\n");
fclose(fp);
exit(0);
}
void
do_print_public(struct passwd *pw)
{
Key *k;
int len;
unsigned char *blob;
struct stat st;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
k = key_new(KEY_DSA);
if (!try_load_key(identity_file, k)) {
fprintf(stderr, "load failed\n");
exit(1);
}
dsa_make_key_blob(k, &blob, &len);
if (!key_write(k, stdout))
fprintf(stderr, "key_write failed");
key_free(k);
xfree(blob);
fprintf(stdout, "\n");
exit(0);
}
void
do_fingerprint(struct passwd *pw)
{
/* XXX RSA1 only */
FILE *f;
Key *public;
char *comment = NULL, *cp, *ep, line[16*1024];
int i, skip = 0, num = 1, invalid = 1;
unsigned int ignore;
struct stat st;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
public = key_new(KEY_RSA);
if (load_public_key(identity_file, public, &comment)) {
printf("%d %s %s\n", BN_num_bits(public->rsa->n),
key_fingerprint(public), comment);
key_free(public);
exit(0);
}
f = fopen(identity_file, "r");
if (f != NULL) {
while (fgets(line, sizeof(line), f)) {
i = strlen(line) - 1;
if (line[i] != '\n') {
error("line %d too long: %.40s...", num, line);
skip = 1;
continue;
}
num++;
if (skip) {
skip = 0;
continue;
}
line[i] = '\0';
/* Skip leading whitespace, empty and comment lines. */
for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
;
if (!*cp || *cp == '\n' || *cp == '#')
continue ;
i = strtol(cp, &ep, 10);
if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
int quoted = 0;
comment = cp;
for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
if (*cp == '\\' && cp[1] == '"')
cp++; /* Skip both */
else if (*cp == '"')
quoted = !quoted;
}
if (!*cp)
continue;
*cp++ = '\0';
}
ep = cp;
if (auth_rsa_read_key(&cp, &ignore, public->rsa->e, public->rsa->n)) {
invalid = 0;
comment = *cp ? cp : comment;
printf("%d %s %s\n", key_size(public),
key_fingerprint(public),
comment ? comment : "no comment");
}
}
fclose(f);
}
key_free(public);
if (invalid) {
printf("%s is not a valid key file.\n", identity_file);
exit(1);
}
exit(0);
}
/*
* Perform changing a passphrase. The argument is the passwd structure
* for the current user.
*/
void
do_change_passphrase(struct passwd *pw)
{
char *comment;
char *old_passphrase, *passphrase1, *passphrase2;
struct stat st;
Key *private;
Key *public;
int type = dsa_mode ? KEY_DSA : KEY_RSA;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
if (type == KEY_RSA) {
/* XXX this works currently only for RSA */
public = key_new(type);
if (!load_public_key(identity_file, public, NULL)) {
printf("%s is not a valid key file.\n", identity_file);
exit(1);
}
/* Clear the public key since we are just about to load the whole file. */
key_free(public);
}
/* Try to load the file with empty passphrase. */
private = key_new(type);
if (!load_private_key(identity_file, "", private, &comment)) {
if (identity_passphrase)
old_passphrase = xstrdup(identity_passphrase);
else
old_passphrase = read_passphrase("Enter old passphrase: ", 1);
if (!load_private_key(identity_file, old_passphrase, private, &comment)) {
memset(old_passphrase, 0, strlen(old_passphrase));
xfree(old_passphrase);
printf("Bad passphrase.\n");
exit(1);
}
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(identity_file, passphrase1, private, comment)) {
printf("Saving the key failed: %s: %s.\n",
identity_file, strerror(errno));
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
key_free(private);
xfree(comment);
exit(1);
}
/* Destroy the passphrase and the copy of the key in memory. */
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
key_free(private); /* 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 new_comment[1024], *comment;
Key *private;
Key *public;
char *passphrase;
struct stat st;
FILE *f;
if (!have_identity)
ask_filename(pw, "Enter file in which the key is");
if (stat(identity_file, &st) < 0) {
perror(identity_file);
exit(1);
}
/*
* Try to load the public key from the file the verify that it is
* readable and of the proper format.
*/
public = key_new(KEY_RSA);
if (!load_public_key(identity_file, public, NULL)) {
printf("%s is not a valid key file.\n", identity_file);
exit(1);
}
private = key_new(KEY_RSA);
if (load_private_key(identity_file, "", private, &comment))
passphrase = xstrdup("");
else {
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(identity_file, passphrase, private, &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) {
strlcpy(new_comment, identity_comment, sizeof(new_comment));
} else {
printf("Enter new comment: ");
fflush(stdout);
if (!fgets(new_comment, sizeof(new_comment), stdin)) {
memset(passphrase, 0, strlen(passphrase));
key_free(private);
exit(1);
}
if (strchr(new_comment, '\n'))
*strchr(new_comment, '\n') = 0;
}
/* Save the file using the new passphrase. */
if (!save_private_key(identity_file, passphrase, private, new_comment)) {
printf("Saving the key failed: %s: %s.\n",
identity_file, strerror(errno));
memset(passphrase, 0, strlen(passphrase));
xfree(passphrase);
key_free(private);
xfree(comment);
exit(1);
}
memset(passphrase, 0, strlen(passphrase));
xfree(passphrase);
key_free(private);
strlcat(identity_file, ".pub", sizeof(identity_file));
f = fopen(identity_file, "w");
if (!f) {
printf("Could not save your public key in %s\n", identity_file);
exit(1);
}
if (!key_write(public, f))
fprintf(stderr, "write key failed");
key_free(public);
fprintf(f, " %s\n", new_comment);
fclose(f);
xfree(comment);
printf("The comment in your key file has been changed.\n");
exit(0);
}
void
usage(void)
{
printf("Usage: %s [-lpqxXydc] [-b bits] [-f file] [-C comment] [-N new-pass] [-P pass]\n", __progname);
exit(1);
}
/*
* Main program for key management.
*/
int
main(int ac, char **av)
{
char dotsshdir[16 * 1024], comment[1024], *passphrase1, *passphrase2;
struct passwd *pw;
int opt;
struct stat st;
FILE *f;
Key *private;
Key *public;
extern int optind;
extern char *optarg;
init_rng();
SSLeay_add_all_algorithms();
/* we need this for the home * directory. */
pw = getpwuid(getuid());
if (!pw) {
printf("You don't exist, go away!\n");
exit(1);
}
if (gethostname(hostname, sizeof(hostname)) < 0) {
perror("gethostname");
exit(1);
}
while ((opt = getopt(ac, av, "dqpclRxXyb: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 'l':
print_fingerprint = 1;
break;
case 'p':
change_passphrase = 1;
break;
case 'c':
change_comment = 1;
break;
case 'f':
strlcpy(identity_file, optarg, sizeof(identity_file));
have_identity = 1;
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 'R':
if (rsa_alive() == 0)
exit(1);
else
exit(0);
break;
case 'x':
convert_to_ssh2 = 1;
break;
case 'X':
convert_from_ssh2 = 1;
break;
case 'y':
print_public = 1;
break;
case 'd':
dsa_mode = 1;
break;
case '?':
default:
usage();
}
}
if (optind < ac) {
printf("Too many arguments.\n");
usage();
}
if (change_passphrase && change_comment) {
printf("Can only have one of -p and -c.\n");
usage();
}
/* check if RSA support is needed and exists */
if (dsa_mode == 0 && rsa_alive() == 0) {
fprintf(stderr,
"%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
__progname);
exit(1);
}
if (print_fingerprint)
do_fingerprint(pw);
if (change_passphrase)
do_change_passphrase(pw);
if (change_comment)
do_change_comment(pw);
if (convert_to_ssh2)
do_convert_to_ssh2(pw);
if (convert_from_ssh2)
do_convert_from_ssh2(pw);
if (print_public)
do_print_public(pw);
arc4random_stir();
if (dsa_mode != 0) {
if (!quiet)
printf("Generating DSA parameter and key.\n");
public = private = dsa_generate_key(bits);
if (private == NULL) {
fprintf(stderr, "dsa_generate_keys failed");
exit(1);
}
} else {
if (quiet)
rsa_set_verbose(0);
/* Generate the rsa key pair. */
public = key_new(KEY_RSA);
private = key_new(KEY_RSA);
rsa_generate_key(private->rsa, public->rsa, bits);
}
if (!have_identity)
ask_filename(pw, "Enter file in which to save the key");
/* Create ~/.ssh directory if it doesn\'t already exist. */
snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, SSH_USER_DIR);
if (strstr(identity_file, dotsshdir) != NULL &&
stat(dotsshdir, &st) < 0) {
if (mkdir(dotsshdir, 0700) < 0)
error("Could not create directory '%s'.", dotsshdir);
else if (!quiet)
printf("Created directory '%s'.\n", dotsshdir);
}
/* If the file already exists, ask the user to confirm. */
if (stat(identity_file, &st) >= 0) {
char yesno[3];
printf("%s already exists.\n", identity_file);
printf("Overwrite (y/n)? ");
fflush(stdout);
if (fgets(yesno, sizeof(yesno), stdin) == NULL)
exit(1);
if (yesno[0] != 'y' && yesno[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);
}
if (identity_comment) {
strlcpy(comment, identity_comment, sizeof(comment));
} else {
/* Create default commend field for the passphrase. */
snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
}
/* Save the key with the given passphrase and comment. */
if (!save_private_key(identity_file, passphrase1, private, comment)) {
printf("Saving the key failed: %s: %s.\n",
identity_file, strerror(errno));
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
exit(1);
}
/* Clear the passphrase. */
memset(passphrase1, 0, strlen(passphrase1));
xfree(passphrase1);
/* Clear the private key and the random number generator. */
if (private != public) {
key_free(private);
}
arc4random_stir();
if (!quiet)
printf("Your identification has been saved in %s.\n", identity_file);
strlcat(identity_file, ".pub", sizeof(identity_file));
f = fopen(identity_file, "w");
if (!f) {
printf("Could not save your public key in %s\n", identity_file);
exit(1);
}
if (!key_write(public, f))
fprintf(stderr, "write key failed");
fprintf(f, " %s\n", comment);
fclose(f);
if (!quiet) {
printf("Your public key has been saved in %s.\n",
identity_file);
printf("The key fingerprint is:\n");
printf("%s %s\n", key_fingerprint(public), comment);
}
key_free(public);
exit(0);
}
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