ssh-keygen.c

OpenSSL Source code for SFTP, SSH, and many others

/*
 * Author: Tatu Ylonen <[e-mail]>
 * Copyright (c) 1994 Tatu Ylonen <[e-mail]>, 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 1.100 2002/06/19 00:27:55 deraadt Exp $");

#include <openssl/evp.h>
#include <openssl/pem.h>

#include "xmalloc.h"
#include "key.h"
#include "rsa.h"
#include "authfile.h"
#include "uuencode.h"
#include "buffer.h"
#include "bufaux.h"
#include "pathnames.h"
#include "log.h"
#include "readpass.h"

#ifdef SMARTCARD
#include "scard.h"
#endif

/* 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;
int print_bubblebabble = 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;

char *key_type_name = NULL;

/* argv0 */
#ifdef HAVE___PROGNAME
extern char *__progname;
#else
char *__progname;
#endif

char hostname[MAXHOSTNAMELEN];

static void
ask_filename(struct passwd *pw, const char *prompt)
{
	char buf[1024];
	char *name = NULL;

	if (key_type_name == NULL)
		name = _PATH_SSH_CLIENT_ID_RSA;
	else
		switch (key_type_from_name(key_type_name)) {
		case KEY_RSA1:
			name = _PATH_SSH_CLIENT_IDENTITY;
			break;
		case KEY_DSA:
			name = _PATH_SSH_CLIENT_ID_DSA;
			break;
		case KEY_RSA:
			name = _PATH_SSH_CLIENT_ID_RSA;
			break;
		default:
			fprintf(stderr, "bad key type");
			exit(1);
			break;
		}

	snprintf(identity_file, sizeof(identity_file), "%s/%s", pw->pw_dir, name);
	fprintf(stderr, "%s (%s): ", prompt, identity_file);
	fflush(stderr);
	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;
}

static Key *
load_identity(char *filename)
{
	char *pass;
	Key *prv;

	prv = key_load_private(filename, "", NULL);
	if (prv == NULL) {
		if (identity_passphrase)
			pass = xstrdup(identity_passphrase);
		else
			pass = read_passphrase("Enter passphrase: ",
			    RP_ALLOW_STDIN);
		prv = key_load_private(filename, pass, NULL);
		memset(pass, 0, strlen(pass));
		xfree(pass);
	}
	return prv;
}

#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

static void
do_convert_to_ssh2(struct passwd *pw)
{
	Key *k;
	u_int len;
	u_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);
	}
	if ((k = key_load_public(identity_file, NULL)) == NULL) {
		if ((k = load_identity(identity_file)) == NULL) {
			fprintf(stderr, "load failed\n");
			exit(1);
		}
	}
	if (key_to_blob(k, &blob, &len) <= 0) {
		fprintf(stderr, "key_to_blob failed\n");
		exit(1);
	}
	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);
}

static 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: "
		    "need %d have %d", bytes, buffer_len(b));
	BN_bin2bn(buffer_ptr(b), bytes, value);
	buffer_consume(b, bytes);
}

static Key *
do_convert_private_ssh2_from_blob(u_char *blob, u_int blen)
{
	Buffer b;
	Key *key = NULL;
	char *type, *cipher;
	u_char *sig, data[] = "abcde12345";
	int magic, rlen, ktype, i1, i2, i3, i4;
	u_int slen;
	u_long e;

	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;
	}
	i1 = buffer_get_int(&b);
	type   = buffer_get_string(&b, NULL);
	cipher = buffer_get_string(&b, NULL);
	i2 = buffer_get_int(&b);
	i3 = buffer_get_int(&b);
	i4 = buffer_get_int(&b);
	debug("ignore (%d %d %d %d)", i1,i2,i3,i4);
	if (strcmp(cipher, "none") != 0) {
		error("unsupported cipher %s", cipher);
		xfree(cipher);
		buffer_free(&b);
		xfree(type);
		return NULL;
	}
	xfree(cipher);

	if (strstr(type, "dsa")) {
		ktype = KEY_DSA;
	} else if (strstr(type, "rsa")) {
		ktype = KEY_RSA;
	} else {
		xfree(type);
		return NULL;
	}
	key = key_new_private(ktype);
	xfree(type);

	switch (key->type) {
	case KEY_DSA:
		buffer_get_bignum_bits(&b, key->dsa->p);
		buffer_get_bignum_bits(&b, key->dsa->g);
		buffer_get_bignum_bits(&b, key->dsa->q);
		buffer_get_bignum_bits(&b, key->dsa->pub_key);
		buffer_get_bignum_bits(&b, key->dsa->priv_key);
		break;
	case KEY_RSA:
		e  = buffer_get_char(&b);
		debug("e %lx", e);
		if (e < 30) {
			e <<= 8;
			e += buffer_get_char(&b);
			debug("e %lx", e);
			e <<= 8;
			e += buffer_get_char(&b);
			debug("e %lx", e);
		}
		if (!BN_set_word(key->rsa->e, e)) {
			buffer_free(&b);
			key_free(key);
			return NULL;
		}
		buffer_get_bignum_bits(&b, key->rsa->d);
		buffer_get_bignum_bits(&b, key->rsa->n);
		buffer_get_bignum_bits(&b, key->rsa->iqmp);
		buffer_get_bignum_bits(&b, key->rsa->q);
		buffer_get_bignum_bits(&b, key->rsa->p);
		rsa_generate_additional_parameters(key->rsa);
		break;
	}
	rlen = buffer_len(&b);
	if (rlen != 0)
		error("do_convert_private_ssh2_from_blob: "
		    "remaining bytes in key blob %d", rlen);
	buffer_free(&b);

	/* try the key */
	key_sign(key, &sig, &slen, data, sizeof(data));
	key_verify(key, sig, slen, data, sizeof(data));
	xfree(sig);
	return key;
}

static void
do_convert_from_ssh2(struct passwd *pw)
{
	Key *k;
	int blen;
	u_int len;
	char line[1024], *p;
	u_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;
			if (strstr(line, " END ") != NULL) {
				break;
			}
			/* fprintf(stderr, "ignore: %s", line); */
			continue;
		}
		if (escaped) {
			escaped--;
			/* fprintf(stderr, "escaped: %s", line); */
			continue;
		}
		*p = '\0';
		strlcat(encoded, line, sizeof(encoded));
	}
	len = strlen(encoded);
	if (((len % 4) == 3) &&
	    (encoded[len-1] == '=') &&
	    (encoded[len-2] == '=') &&
	    (encoded[len-3] == '='))
		encoded[len-3] = '\0';
	blen = uudecode(encoded, blob, sizeof(blob));
	if (blen < 0) {
		fprintf(stderr, "uudecode failed.\n");
		exit(1);
	}
	k = private ?
	    do_convert_private_ssh2_from_blob(blob, blen) :
	    key_from_blob(blob, blen);
	if (k == NULL) {
		fprintf(stderr, "decode blob failed.\n");
		exit(1);
	}
	ok = private ?
	    (k->type == KEY_DSA ?
		 PEM_write_DSAPrivateKey(stdout, k->dsa, NULL, NULL, 0, NULL, NULL) :
		 PEM_write_RSAPrivateKey(stdout, k->rsa, NULL, NULL, 0, NULL, NULL)) :
	    key_write(k, stdout);
	if (!ok) {
		fprintf(stderr, "key write failed");
		exit(1);
	}
	key_free(k);
	if (!private)
		fprintf(stdout, "\n");
	fclose(fp);
	exit(0);
}

static void
do_print_public(struct passwd *pw)
{
	Key *prv;
	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);
	}
	prv = load_identity(identity_file);
	if (prv == NULL) {
		fprintf(stderr, "load failed\n");
		exit(1);
	}
	if (!key_write(prv, stdout))
		fprintf(stderr, "key_write failed");
	key_free(prv);
	fprintf(stdout, "\n");
	exit(0);
}

#ifdef SMARTCARD
static void
do_upload(struct passwd *pw, const char *sc_reader_id)
{
	Key *prv = NULL;
	struct stat st;
	int ret;

	if (!have_identity)
		ask_filename(pw, "Enter file in which the key is");
	if (stat(identity_file, &st) < 0) {
		perror(identity_file);
		exit(1);
	}
	prv = load_identity(identity_file);
	if (prv == NULL) {
		error("load failed");
		exit(1);
	}
	ret = sc_put_key(prv, sc_reader_id);
	key_free(prv);
	if (ret < 0)
		exit(1);
	log("loading key done");
	exit(0);
}

static void
do_download(struct passwd *pw, const char *sc_reader_id)
{
	Key **keys = NULL;
	int i;

	keys = sc_get_keys(sc_reader_id, NULL);
	if (keys == NULL)
		fatal("cannot read public key from smartcard");
	for (i = 0; keys[i]; i++) {
		key_write(keys[i], stdout);
		key_free(keys[i]);
		fprintf(stdout, "\n");
	}
	xfree(keys);
	exit(0);
}
#endif /* SMARTCARD */

static void
do_fingerprint(struct passwd *pw)
{
	FILE *f;
	Key *public;
	char *comment = NULL, *cp, *ep, line[16*1024], *fp;
	int i, skip = 0, num = 1, invalid = 1;
	enum fp_rep rep;
	enum fp_type fptype;
	struct stat st;

	fptype = print_bubblebabble ? SSH_FP_SHA1 : SSH_FP_MD5;
	rep =    print_bubblebabble ? SSH_FP_BUBBLEBABBLE : SSH_FP_HEX;

	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_load_public(identity_file, &comment);
	if (public != NULL) {
		fp = key_fingerprint(public, fptype, rep);
		printf("%d %s %s\n", key_size(public), fp, comment);
		key_free(public);
		xfree(comment);
		xfree(fp);
		exit(0);
	}
	if (comment)
		xfree(comment);

	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 == '"')