view dropbearkey.c @ 1659:d32bcb5c557d

Add Ed25519 support (#91) * Add support for Ed25519 as a public key type Ed25519 is a elliptic curve signature scheme that offers better security than ECDSA and DSA and good performance. It may be used for both user and host keys. OpenSSH key import and fuzzer are not supported yet. Initially inspired by Peter Szabo. * Add curve25519 and ed25519 fuzzers * Add import and export of Ed25519 keys
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Wed, 11 Mar 2020 21:09:45 +0500
parents bdd3802c8ac6
children 435cfb9ec96e
line wrap: on
line source
/*
 * Dropbear - a SSH2 server
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE. */

/* The format of the keyfiles is basically a raw dump of the buffer. Data types
 * are specified in the transport rfc 4253 - string is a 32-bit len then the
 * non-null-terminated string, mp_int is a 32-bit len then the bignum data.
 * The actual functions are buf_put_rsa_priv_key() and buf_put_dss_priv_key()

 * RSA:
 * string	"ssh-rsa"
 * mp_int	e
 * mp_int	n
 * mp_int	d
 * mp_int	p (newer versions only)
 * mp_int	q (newer versions only) 
 *
 * DSS:
 * string	"ssh-dss"
 * mp_int	p
 * mp_int	q
 * mp_int	g
 * mp_int	y
 * mp_int	x
 *
 * Ed25519:
 * string	"ssh-ed25519"
 * string	k (32 bytes) + A (32 bytes)
 *
 */
#include "includes.h"
#include "signkey.h"
#include "buffer.h"
#include "dbutil.h"

#include "genrsa.h"
#include "gendss.h"
#include "gened25519.h"
#include "ecdsa.h"
#include "crypto_desc.h"
#include "dbrandom.h"
#include "gensignkey.h"

static void printhelp(char * progname);


static void printpubkey(sign_key * key, int keytype);
static int printpubfile(const char* filename);

/* Print a help message */
static void printhelp(char * progname) {

	fprintf(stderr, "Usage: %s -t <type> -f <filename> [-s bits]\n"
					"-t type	Type of key to generate. One of:\n"
#if DROPBEAR_RSA
					"		rsa\n"
#endif
#if DROPBEAR_DSS
					"		dss\n"
#endif
#if DROPBEAR_ECDSA
					"		ecdsa\n"
#endif
#if DROPBEAR_ED25519
					"		ed25519\n"
#endif
					"-f filename    Use filename for the secret key.\n"
					"               ~/.ssh/id_dropbear is recommended for client keys.\n"
					"-s bits	Key size in bits, should be a multiple of 8 (optional)\n"
#if DROPBEAR_DSS
					"           DSS has a fixed size of 1024 bits\n"
#endif
#if DROPBEAR_ECDSA
					"           ECDSA has sizes "
#if DROPBEAR_ECC_256
					"256 "
#endif
#if DROPBEAR_ECC_384
					"384 "
#endif
#if DROPBEAR_ECC_521
					"521 "
#endif
					"\n"
#endif
#if DROPBEAR_ED25519
					"           Ed25519 has a fixed size of 256 bits\n"
#endif
					"-y		Just print the publickey and fingerprint for the\n		private key in <filename>.\n"
#if DEBUG_TRACE
					"-v		verbose\n"
#endif
					,progname);
}

/* fails fatally */
static void check_signkey_bits(enum signkey_type type, int bits)
{
	switch (type) {
#if DROPBEAR_ED25519
		case DROPBEAR_SIGNKEY_ED25519:
			if (bits != 256) {
				dropbear_exit("Ed25519 keys have a fixed size of 256 bits\n");
				exit(EXIT_FAILURE);
			}
			break;
#endif
#if DROPBEAR_RSA
		case DROPBEAR_SIGNKEY_RSA:
			if (bits < 512 || bits > 4096 || (bits % 8 != 0)) {
				dropbear_exit("Bits must satisfy 512 <= bits <= 4096, and be a"
				              " multiple of 8\n");
			}
			break;
#endif
#ifdef DROPEAR_DSS
		case DROPBEAR_SIGNKEY_DSS:
			if (bits != 1024) {
				dropbear_exit("DSS keys have a fixed size of 1024 bits\n");
				exit(EXIT_FAILURE);
			}
#endif
		default:
			(void)0; /* quiet, compiler. ecdsa handles checks itself */
	}
}

#if defined(DBMULTI_dropbearkey) || !DROPBEAR_MULTI
#if defined(DBMULTI_dropbearkey) && DROPBEAR_MULTI
int dropbearkey_main(int argc, char ** argv) {
#else
int main(int argc, char ** argv) {
#endif

	int i;
	char ** next = NULL;
	char * filename = NULL;
	enum signkey_type keytype = DROPBEAR_SIGNKEY_NONE;
	char * typetext = NULL;
	char * sizetext = NULL;
	unsigned int bits = 0, genbits;
	int printpub = 0;

	crypto_init();
	seedrandom();

	/* get the commandline options */
	for (i = 1; i < argc; i++) {
		if (argv[i] == NULL) {
			continue; /* Whack */
		} 
		if (next) {
			*next = argv[i];
			next = NULL;
			continue;
		}

		if (argv[i][0] == '-') {
			switch (argv[i][1]) {
				case 'f':
					next = &filename;
					break;
				case 't':
					next = &typetext;
					break;
				case 's':
					next = &sizetext;
					break;
				case 'y':
					printpub = 1;
					break;
				case 'h':
					printhelp(argv[0]);
					exit(EXIT_SUCCESS);
					break;
#if DEBUG_TRACE
				case 'v':
					debug_trace = 1;
					break;
#endif
				default:
					fprintf(stderr, "Unknown argument %s\n", argv[i]);
					printhelp(argv[0]);
					exit(EXIT_FAILURE);
					break;
			}
		}
	}

	if (!filename) {
		fprintf(stderr, "Must specify a key filename\n");
		printhelp(argv[0]);
		exit(EXIT_FAILURE);
	}

	if (printpub) {
		int ret = printpubfile(filename);
		exit(ret);
	}

	/* check/parse args */
	if (!typetext) {
		fprintf(stderr, "Must specify key type\n");
		printhelp(argv[0]);
		exit(EXIT_FAILURE);
	}

#if DROPBEAR_RSA
	if (strcmp(typetext, "rsa") == 0)
	{
		keytype = DROPBEAR_SIGNKEY_RSA;
	}
#endif
#if DROPBEAR_DSS
	if (strcmp(typetext, "dss") == 0)
	{
		keytype = DROPBEAR_SIGNKEY_DSS;
	}
#endif
#if DROPBEAR_ECDSA
	if (strcmp(typetext, "ecdsa") == 0)
	{
		keytype = DROPBEAR_SIGNKEY_ECDSA_KEYGEN;
	}
#endif
#if DROPBEAR_ED25519
	if (strcmp(typetext, "ed25519") == 0)
	{
		keytype = DROPBEAR_SIGNKEY_ED25519;
	}
#endif

	if (keytype == DROPBEAR_SIGNKEY_NONE) {
		fprintf(stderr, "Unknown key type '%s'\n", typetext);
		printhelp(argv[0]);
		exit(EXIT_FAILURE);
	}

	if (sizetext) {
		if (sscanf(sizetext, "%u", &bits) != 1) {
			fprintf(stderr, "Bits must be an integer\n");
			exit(EXIT_FAILURE);
		}
		
		check_signkey_bits(keytype, bits);;
	}

	genbits = signkey_generate_get_bits(keytype, bits);
	fprintf(stderr, "Generating %u bit %s key, this may take a while...\n", genbits, typetext);
	if (signkey_generate(keytype, bits, filename, 0) == DROPBEAR_FAILURE)
	{
		dropbear_exit("Failed to generate key.\n");
	}

	printpubfile(filename);

	return EXIT_SUCCESS;
}
#endif

static int printpubfile(const char* filename) {

	buffer *buf = NULL;
	sign_key *key = NULL;
	enum signkey_type keytype;
	int ret;
	int err = DROPBEAR_FAILURE;

	buf = buf_new(MAX_PRIVKEY_SIZE);
	ret = buf_readfile(buf, filename);

	if (ret != DROPBEAR_SUCCESS) {
		fprintf(stderr, "Failed reading '%s'\n", filename);
		goto out;
	}

	key = new_sign_key();
	keytype = DROPBEAR_SIGNKEY_ANY;

	buf_setpos(buf, 0);
	ret = buf_get_priv_key(buf, key, &keytype);
	if (ret == DROPBEAR_FAILURE) {
		fprintf(stderr, "Bad key in '%s'\n", filename);
		goto out;
	}

	printpubkey(key, keytype);

	err = DROPBEAR_SUCCESS;

out:
	buf_burn(buf);
	buf_free(buf);
	buf = NULL;
	if (key) {
		sign_key_free(key);
		key = NULL;
	}
	return err;
}

static void printpubkey(sign_key * key, int keytype) {

	buffer * buf = NULL;
	unsigned char base64key[MAX_PUBKEY_SIZE*2];
	unsigned long base64len;
	int err;
	const char * typestring = NULL;
	char *fp = NULL;
	int len;
	struct passwd * pw = NULL;
	char * username = NULL;
	char hostname[100];

	buf = buf_new(MAX_PUBKEY_SIZE);
	buf_put_pub_key(buf, key, keytype);
	buf_setpos(buf, 4);

	len = buf->len - buf->pos;

	base64len = sizeof(base64key);
	err = base64_encode(buf_getptr(buf, len), len, base64key, &base64len);

	if (err != CRYPT_OK) {
		fprintf(stderr, "base64 failed");
	}

	typestring = signkey_name_from_type(keytype, NULL);

	fp = sign_key_fingerprint(buf_getptr(buf, len), len);

	/* a [email protected] comment is informative */
	username = "";
	pw = getpwuid(getuid());
	if (pw) {
		username = pw->pw_name;
	}

	gethostname(hostname, sizeof(hostname));
	hostname[sizeof(hostname)-1] = '\0';

	printf("Public key portion is:\n%s %s %[email protected]%s\nFingerprint: %s\n",
			typestring, base64key, username, hostname, fp);

	m_free(fp);
	buf_free(buf);
}