view dropbearconvert.c @ 1851:7f549ee3df48

Use HOME before /etc/passwd to find id_dropbear (#137) Currently dbclient uses the value of HOME by default when looking for ~/.ssh/known_hosts, falling back to /etc/passwd if HOME is not set (so that people can work around broken values in /etc/passwd). However, when locating the default authentication key (defaults to ~/.ssh/id_dropbear), paths not starting with / are always prefixed with the value from /etc/passwd. Make the behaviour consistent by adjusting expand_homedir_path to use the value of HOME, falling back to /etc/passwd if HOME is not set.
author Matt Robinson <git@nerdoftheherd.com>
date Tue, 19 Oct 2021 06:02:47 +0100
parents 750ec4ec4cbe
children be236878efcf
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. */

/* This program converts to/from Dropbear and OpenSSH private-key formats */
#include "includes.h"
#include "signkey.h"
#include "buffer.h"
#include "dbutil.h"
#include "keyimport.h"
#include "crypto_desc.h" 
#include "dbrandom.h" 


static int do_convert(int intype, const char* infile, int outtype,
		const char* outfile);

static void printhelp(char * progname);

static void printhelp(char * progname) {

	fprintf(stderr, "Usage: %s <inputtype> <outputtype> <inputfile> <outputfile>\n\n"
					"CAUTION: This program is for convenience only, and is not secure if used on\n"
					"untrusted input files, ie it could allow arbitrary code execution.\n"
					"All parameters must be specified in order.\n"
					"\n"
					"The input and output types are one of:\n"
					"openssh\n"
					"dropbear\n"
					"\n"
					"Example:\n"
					"dropbearconvert openssh dropbear /etc/ssh/ssh_host_rsa_key /etc/dropbear_rsa_host_key\n",
					progname);
}

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

	int intype, outtype;
	const char* infile;
	const char* outfile;

	crypto_init();
	seedrandom();

#if DEBUG_TRACE
	/* It's hard for it to get in the way _too_ much */
	debug_trace = 1;
#endif

	/* get the commandline options */
	if (argc != 5) {
		fprintf(stderr, "All arguments must be specified\n");
		goto usage;
	}

	/* input type */
	if (argv[1][0] == 'd') {
		intype = KEYFILE_DROPBEAR;
	} else if (argv[1][0] == 'o') {
		intype = KEYFILE_OPENSSH;
	} else {
		fprintf(stderr, "Invalid input key type\n");
		goto usage;
	}

	/* output type */
	if (argv[2][0] == 'd') {
		outtype = KEYFILE_DROPBEAR;
	} else if (argv[2][0] == 'o') {
		outtype = KEYFILE_OPENSSH;
	} else {
		fprintf(stderr, "Invalid output key type\n");
		goto usage;
	}

	/* we don't want output readable by others */
	umask(077);

	infile = argv[3];
	outfile = argv[4];

	return do_convert(intype, infile, outtype, outfile);

usage:
	printhelp(argv[0]);
	return 1;
}
#endif

static int do_convert(int intype, const char* infile, int outtype,
		const char* outfile) {

	sign_key * key = NULL;
	const char * keytype = NULL;
	int ret = 1;

	key = import_read(infile, NULL, intype);
	if (!key) {
		fprintf(stderr, "Error reading key from '%s'\n",
				infile);
		goto out;
	}

	keytype = signkey_name_from_type(key->type, NULL);

	fprintf(stderr, "Key is a %s key\n", keytype);

	if (import_write(outfile, key, NULL, outtype) != 1) {
		fprintf(stderr, "Error writing key to '%s'\n", outfile);
	} else {
		fprintf(stderr, "Wrote key to '%s'\n", outfile);
		ret = 0;
	}

out:
	if (key) {
		sign_key_free(key);
	}
	return ret;
}